95 results on '"Fleming SD"'
Search Results
2. Cryopreservation-induced human sperm DNA damage is predominantly mediated by oxidative stress rather than apoptosis
- Author
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Thomson, LK, Fleming, SD, Aitken, RJ, De Iuliis, GN, Zieschang, J-A, and Clark, AM
- Published
- 2009
3. Action of hypoxanthine and meiosis-activating sterol on oocyte maturation in the mouse is strain specific
- Author
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Griffin, AM, Grondahl, C, and Fleming, SD
- Published
- 2004
- Full Text
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4. The predictive value of the zone-free hamster egg penetration test in relation to in-vitro fertilization at various insemination concentrations.
- Author
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Rashid, MRZ, Fishel, SB, Thornton, S, Hall, JA, Ndukwe, G, Aloum, M, and Fleming, SD
- Abstract
The aim of the study was to evaluate the predictive value of the zone-free hamster egg penetration test (ZHEPT) for success in in-vitro fertilization (IVF) at various insemination concentrations ranging between 0.1 and >0.6 x 106/ml. The ZHEPT was assessed using sperm samples from 87 couples undergoing IVF treatment. A similar test was simultaneously performed on the same semen sample following ionophore induction of the acrosome reaction (ZHEPTii test). Both the tests were poorly correlated with the fertilization rate of IVF at all the insemination concentrations except at >0.6 x 106/ml, when there was good correlation between the ZHEPTii test and the fertilization rate. Following exclusion of two cases with an oocyte problem, further statistical analysis revealed that both the ZHEPT and ZHEPTii tests were poorly correlated with fertilization rate in IVF in this treatment group. This study suggests that the ZHEPT (with and without ionophore induction of the acrosome reaction) has a poor predictive value for the success of fertilization in IVF treatment at any insemination concentration. [ABSTRACT FROM PUBLISHER]
- Published
- 1998
- Full Text
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5. Clinical Burden and Health Care Resource Utilization Associated With Managing Sickle Cell Disease With Recurrent Vaso-occlusive Crises in England.
- Author
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Udeze C, Ly NF, Ingleby FC, Fleming SD, Conner SC, Howard J, Li N, and Shah F
- Abstract
Purpose: Sickle cell disease (SCD) is an inherited red blood cell disease caused by a mutation in the gene encoding the β-subunit of adult hemoglobin that leads to hemolysis, anemia, vaso-occlusive crises (VOCs), morbidity, and mortality. This study provides a real-world assessment of the clinical burden and health care resource utilization (HCRU) associated with SCD with recurrent VOCs in England., Methods: This retrospective study linked primary care records from the Clinical Practice Research Datalink database with secondary care records from the Hospital Episode Statistics database to identify patients with SCD with recurrent VOCs between July 1, 2008, and June 30, 2018. A VOC was defined as SCD with crisis, acute chest syndrome, or priapism. Eligible patients had SCD, ≥2 VOCs/year in any 2 consecutive years after a diagnosis of SCD, and ≥1 year of follow-up data from the index date. Patients were exact matched with 5 controls from the general population in the databases. Demographics were assessed at index. Mortality, clinical complications, and HCRU were summarized during follow-up., Findings: After applying eligibility criteria, 1117 patients with SCD with recurrent VOCs and 5585 controls were included in the study. Mean age at index was 25 years in both groups. The proportion of deaths (3.67% vs 0.68%; P < 0.001) and mortality rate (0.78 deaths per 100 person-years vs 0.16 deaths per 100 person-years) were substantially higher in patients with SCD with recurrent VOCs versus matched controls. Mean (standard deviation [SD]) age of death in patients with SCD with recurrent VOCs who died during the follow-up period was 40.17 (14.09) years. The mean (SD) rate of VOCs for patients with SCD with recurrent VOCs was 5.84 (12.50) per patient per year (PPPY) during follow-up. Compared with matched controls, patients with SCD with recurrent VOCs had substantially higher mean [SD] rates PPPY of inpatient hospitalizations (7.59 [14.50] vs 0.32 [2.71]), prescriptions (31.06 [60.62] vs 7.58 [27.77]), and outpatient visits (9.60 [10.69] vs 1.78 [4.18]). Older patients and those with increased numbers of VOCs had increased mortality, frequency of clinical complications, and HCRU., Implications: Despite currently available care, patients with SCD with recurrent VOCs in England have increased mortality, substantial clinical complications, and significant HCRU driven by VOCs and hospitalizations. Elevated mortality and clinical complications in patients with SCD with recurrent VOCs highlight the need for novel therapies in this space., Competing Interests: Declaration of competing interest C. Udeze and N. Li are employees of Vertex Pharmaceuticals Incorporated and hold stock or stock options in the company. N.F. Ly, F.C. Ingleby, and S.D. Fleming are employees of IQVIA. S.C. Conner is an employee of Vertex Pharmaceuticals Incorporated and holds stock or stock options in the company and received a grant from the National Heart, Lung, and Blood Institute. J. Howard is an employee of Vertex Pharmaceuticals Incorporated and may hold stock or stock options in the company; reports advisory board and Delphi panel participation for Global Blood Therapeutics/Pfizer; advisory board participation for Novo Nordisk; was a member of a speaker's bureau and a steering committee for Novartis Pharma AG; and received research funding from bluebird bio. F. Shah received payment or honoraria from Bristol Myers Squibb, Chiesi Limited, Novartis Pharma AG, bluebird bio, Global Blood Therapeutics/Pfizer, Agios Pharmaceuticals, Abfero Pharmaceuticals, Silence Therapeutics, and Roche; served as an adjudication or data monitoring committee member for Agios, IQVIA, and Abfero Pharmaceuticals. This study was supported by Vertex Pharmaceuticals Incorporated., (Copyright © 2024 Vertex Pharmaceuticals Funded the Research. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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6. Clinical Burden and Healthcare Resource Utilization Associated With Managing Transfusion-dependent β-Thalassemia in England.
- Author
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Udeze C, Ly NF, Ingleby FC, Fleming SD, Conner SC, Howard J, Li N, and Shah F
- Abstract
Purpose: Patients with transfusion-dependent β-thalassemia (TDT) have reduced levels of β-globin, leading to ineffective erythropoiesis and iron overload. Patients with TDT depend on regular red blood cell transfusions (RBCTs) and iron chelation therapy for survival and management of disease- and treatment-related clinical complications. This study describes the clinical and economic burden in patients with TDT in England., Methods: This longitudinal, retrospective study linked the Clinical Practice Research Datalink (CPRD) database with secondary care data from the Hospital Episode Statistics database to identify patients with a diagnosis of β-thalassemia between July 1, 2008, and June 30, 2018. Included patients had a diagnosis of β-thalassemia prior to the index date, ≥8 RBCTs per year for ≥2 consecutive years, and ≥1 year of follow-up data available from the index date. Each eligible patient was exact matched with up to 5 controls in the CPRD. Proportions of deaths and rates of mortality, acute and chronic complications, and healthcare resource utilization (HCRU) were calculated during the follow-up period., Findings: Of 11,359 identified patients with β-thalassemia, 237 patients with TDT met the eligibility criteria and were matched with 1184 controls. The mean age at the index date was approximately 25 years in the patient and control groups. The proportion of deaths (7.17% vs 1.18%; P < 0.05) and mortality rate (1.19 deaths per 100 person-years vs 0.20 deaths per 100 person-years) were higher among patients with TDT compared to controls. Endocrine complications and bone disorders were the most prevalent complications among patients with TDT (58.23%) and included osteoporosis (29.11%), diabetes mellitus (28.27%), and hypopituitarism (28.27%). Patients with TDT had a mean of 13.62 RBCTs per patient per year (PPPY). HCRU was substantially higher among patients with TDT, wherein patients with TDT had higher rates of prescriptions recorded in primary care (24.09 vs 8.61 PPPY), outpatient visits (16.69 vs 1.31 PPPY), and inpatient hospitalizations (17.41 vs 0.24 PPPY) than controls. Inpatient hospitalizations were primarily <1 day, with 16.62 events PPPY lasting <1 day and 0.79 events PPPY lasting ≥1 day. Patients with TDT aged ≥18 years had increased rates of mortality, clinical complications, and HCRU than those aged <18 years., Implications: Patients with TDT in England have higher mortality than matched controls, substantial disease-related clinical complications, and substantial HCRU. High mortality and clinical complications highlight the need for additional innovative therapies for TDT., Competing Interests: Declaration of competing interest C. Udeze and N. Li are employees of Vertex Pharmaceuticals Incorporated and hold stock or stock options in the company. N.F. Ly, F.C. Ingleby, and S.D. Fleming are employees of IQVIA. S.C. Conner is an employee of Vertex Pharmaceuticals Incorporated and holds stock or stock options in the company and received a grant from the National Heart, Lung, and Blood Institute. J. Howard is an employee of Vertex Pharmaceuticals Incorporated and may hold stock or stock options in the company; reports advisory board and Delphi panel participation for Global Blood Therapeutics/Pfizer; advisory board participation for Novo Nordisk; was a member of a speaker's bureau and a steering committee for Novartis Pharma AG; and received research funding from Bluebird Bio. F. Shah received payment or honoraria from Bristol Myers Squibb, Chiesi Limited, Novartis Pharma AG, Bluebird Bio, Global Blood Therapeutics/Pfizer, Agios Pharmaceuticals, Abfero Pharmaceuticals, Silence Therapeutics, and Roche; served as an adjudication or data monitoring committee member for Agios, IQVIA, and Abfero Pharmaceuticals., (Copyright © 2024 Vertex Pharmaceuticals Incorporated. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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7. Biodistribution Analysis of Peptide-Coated Magnetic Iron Nanoparticles: A Simple and Quantitative Method.
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Natarajan P, Horak K, Rowe J, Yoon S, Lingo J, Tomich JM, and Fleming SD
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- Mice, Animals, Tissue Distribution, Peptides chemistry, Magnetic Iron Oxide Nanoparticles, Nanoparticles chemistry, Magnetite Nanoparticles chemistry, Benzenesulfonates
- Abstract
Biodistribution tracks compounds or molecules of interest in vivo to understand a compound's anticipated efficacy and safety. Nanoparticles deliver nucleic acid and drug payloads and enhance tumor permeability due to multiple properties such as high surface area to volume ratio, surface functionalization, and modifications. Studying the in vivo biodistribution of nanoparticles documents the effectiveness and safety of nanoparticles and facilitates a more application-driven approach for nanoparticle development that allows for more successful translation into clinical use. In this study, we present a relatively simple method to determine the biodistribution of magnetic iron nanoparticles in mice. In vitro, cells take up branched amphiphilic peptide-coated magnetic nanobeads (BAPc-MNBs) like their counterparts, i.e., branched amphiphilic peptide capsules (BAPCs) with a hollow water-filled core. Both BAPc-MNBs and BAPCs have widespread applications as a nanodelivery system. We evaluated the BAPc-MNBs tissue distribution in wild-type mice injected intravenously (i.v.), intraperitoneally (i.p.), or orally gavaged to understand the biological interactions and to further the development of branched amphiphilic peptide-based nanoparticles. The magnetic nanoparticles allowed collection of the BAPc-MNBs from multiple organs by magnetic bead sorting, followed by a high-throughput screening for iron content. When injected i.v., nanoparticles were distributed widely to various organs before elimination from the system via the intestines in feces. The spleen accumulated the highest amount of BAPc-MNBs in mice administered NPs via i.v. and i.p. but not via oral gavage. Taken together, these data demonstrate that the magnetic sorting not only allowed quantification of the BAPc-MNBs but also identified the distribution of BAPc-MNBs after distinct administration methods.
- Published
- 2024
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8. Intracytoplasmic sperm injection vs. in-vitro fertilization in couples in whom the male partners had a semen analysis within normal reference ranges: An open debate.
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Sciorio R and Fleming SD
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- Male, Humans, Reference Values, Semen, Fertilization in Vitro methods, Semen Analysis, Fertilization, Retrospective Studies, Sperm Injections, Intracytoplasmic, Infertility, Male therapy
- Abstract
During recent decades, the application of intracytoplasmic sperm injection has increased considerably worldwide, especially in couples with non-male factor infertility. However, several studies analyzing the broad use of intracytoplasmic sperm injection, even in cases with a normal semen analysis, have collectively demonstrated no benefits compared to conventional in-vitro fertilization. Currently, there is insufficient evidence to support the intracytoplasmic sperm injection technique vs. in-vitro fertilization in cases of poor ovarian response or a low number of oocytes collected, or in patients with advanced maternal age. Since the intracytoplasmic sperm injection technique is more operator-dependent and invasive, its use should only be recommended in cases of male-factor infertility. There is some evidence showing that intracytoplasmic sperm injection is linked with an increased risk of birth defects. Albeit this evidence is limited, and currently it is not possible to draw a firm conclusion on these concerns, we do believe that these risks should be rigorously investigated. Thus, this review aims to clarify the debate on the application of the intracytoplasmic sperm injection procedure, as compared to standard in-vitro fertilization, in those assisted reproductive technology cycles without a clear male factor infertility. Furthermore, we try to clarify whether intracytoplasmic sperm injection would result in a higher live birth rate than in-vitro fertilization, in couples with non-male factor infertility., (© 2023 American Society of Andrology and European Academy of Andrology.)
- Published
- 2024
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9. Biodistribution Analysis of Peptide-Coated Magnetic Iron Nanoparticles: A Simple and Quantitative Method.
- Author
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Natarajan P, Horak K, Rowe J, Lingo J, Tomich JM, and Fleming SD
- Abstract
Biodistribution is the tracking of compounds or molecules of interest in the subject which is integral to understanding their anticipated efficacy and safety. Nanoparticles are highly desirable delivery systems which have the ability to deliver higher nucleic acid and drug payloads and they have enhanced tumor permeability due to their unique properties such as high surface area to volume ratio. Studying the biodistribution of nanoparticles is crucial to understand their effectiveness and safety in vivo, facilitate a more application driven approach for nanoparticle development which will lead to their successful translation into clinical use. In this study, we present a relatively simple method to determine the biodistribution of magnetic iron nanoparticles in mice. Branched Amphiphilic Peptide coated Magnetic Nanobeads BAPc-MNBs like their counterpart i.e., Branched Amphiphilic Peptide capsules (BAPCs) with a hollow water-filled core, are readily taken up by cells in vitro and have widespread application as a nanodelivery systems. We evaluated the BAPc-MNBs tissue distribution in wildtype mice injected intravenously (i.v.), intraperitoneally (i.p.) or orally gavaged to understand the biological interactions of the peptide nanoparticles and to further the development of branched amphiphilic peptides-based nanoparticles. BAPc-MNBs were distributed widely to various organs when injected i.v. and were eliminated from the system via the intestines in feces. The spleen was found to accumulate the highest amount of BAPc-MNBs in mice administered the NPs i.v. and i.p. while they were not absorbed into the system via oral gavage. This study not only presents a relatively simple quantification method to determine in vivo biodistribution of magnetic iron nanoparticles that can be widely applied but also demonstrates the potential of Branched Amphiphilic Peptides in the form of BAPCs or BAPc-MNBs as a delivery system.
- Published
- 2023
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10. Tick Intrastadial Feeding and Its Role on IgE Production in the Murine Model of Alpha-gal Syndrome: The Tick "Transmission" Hypothesis.
- Author
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Maldonado-Ruiz LP, Boorgula GD, Kim D, Fleming SD, and Park Y
- Subjects
- Amblyomma, Animals, Cattle, Disease Models, Animal, Female, Food Hypersensitivity, Galactose, Immunoglobulin E, Male, Mammals, Mice, Mice, Inbred C57BL, Mice, Knockout, United States, Ticks
- Abstract
Recent studies have provided strong evidence indicating that lone star tick bites are a cause of AGS (alpha-gal syndrome, also known as red meat allergy RMA) in humans. AGS is characterized by an increase in IgE antibody production against galactose-alpha-1,3-galactose (aGal), which is a common glycan found in mammalian tissue, except in Old World monkeys and humans. The main causative factor of AGS, the lone star tick ( Amblyomma americanum ), is broadly distributed throughout the east and midwest of the United States and is a vector of a wide range of human and animal pathogens. Our earlier glycomics study of the salivary glands of partially fed male and female ticks revealed relatively high levels of aGal epitopes. In this study, we found that partially fed males of A. americanum on bovine blood, which engage in multiple intrastadial feedings, carry a large amount of aGal in the salivary glands. In our current work, we aimed to test whether ticks mediate the transmission of the aGal sensitizer acquired from nonhuman blood to humans in the intrastadial host switch (referred to as the "transmission" hypothesis). To test this hypothesis, we used an alpha-galactosyltransferase knockout mutant mouse (aGT-KO) model system infested with ticks that were unfed or partially fed on bovine blood. Based on the levels of total IgE and specific IgG and IgE antibodies against aGal after tick feedings, aGT-KO mice significantly responded to tick feeding and injection of aGal (Galα1-3Galβ1-4GlcNAc) conjugated to human serum albumin or mouse serum albumin (aGal-HSA or aGal-MSA) by increasing total IgE and aGal-specific IgE levels compared to those in C57BL/6 control mice. All of the treatments of aGT-KO mice involving the feeding of partially fed and unfed ticks functioned as sensitizers that increased the levels of specific IgE against aGal, with large individual variations. The data in this study do not support the "transmission" component of AGS, although they confirmed that aGT-KO mice can be used as a model for RMA studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Maldonado-Ruiz, Boorgula, Kim, Fleming and Park.)
- Published
- 2022
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11. Complement Initiation Varies by Sex in Intestinal Ischemia Reperfusion Injury.
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Wu M, Rowe JM, and Fleming SD
- Subjects
- Animals, Complement C1q genetics, Disease Models, Animal, Female, Humans, Intestines blood supply, Intestines immunology, Intestines pathology, Male, Mannose-Binding Lectin genetics, Mice, Mice, Knockout, Properdin genetics, Properdin metabolism, Reperfusion Injury pathology, Sex Factors, Complement C1q metabolism, Complement Pathway, Classical physiology, Complement Pathway, Mannose-Binding Lectin physiology, Mannose-Binding Lectin metabolism, Reperfusion Injury immunology
- Abstract
Intestinal ischemia reperfusion (IR)-induced tissue injury represents an acute inflammatory response with significant morbidity and mortality. The mechanism of IR-induced injury is not fully elucidated, but recent studies suggest a critical role for complement activation and for differences between sexes. To test the hypothesis that complement initiation differs by sex in intestinal IR, we performed intestinal IR on male and female WT C57B6L/, C1q
-/- , MBL-/- , or properdin (P)-/- mice. Intestinal injury, C3b and C5a production and ex vivo secretions were analyzed. Initial studies demonstrated a difference in complement mRNA and protein in male and female WT mice. In response to IR, male C1q-, MBL- and P-deficient mice sustained less injury than male WT mice. In contrast, only female MBL-/- mice sustained significantly less injury than female wildtype mice. Importantly, wildtype, C1q-/- and P-/- female mice sustained significant less injury than the corresponding male mice. In addition, both C1q and MBL expression and deposition increased in WT male mice, while only elevated MBL expression and deposition occurred in WT female mice. These data suggested that males use both C1q and MBL pathways, while females tend to depend on lectin pathway during intestinal IR. Females produced significantly less serum C5a in MBL-/- and P-/- mice. Our findings suggested that complement activation plays a critical role in intestinal IR in a sex-dependent manner., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wu, Rowe and Fleming.)- Published
- 2021
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12. Editorial: Innate Immunity in Normal and Adverse Pregnancy.
- Author
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Burwick RM, Lokki AI, Fleming SD, and Regal JF
- Subjects
- Female, Humans, Models, Immunological, Pregnancy, Adaptive Immunity immunology, Complement System Proteins immunology, Immunity, Innate immunology, Pregnancy Complications, Infectious immunology
- Abstract
Competing Interests: Alexion Pharmaceuticals has supported speaking fees (AL and RB) and research grants (RB) in the past. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Published
- 2021
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13. Beta2 glycoprotein I-derived therapeutic peptides induce sFlt-1 secretion to reduce melanoma vascularity and growth.
- Author
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Smalley H, Rowe JM, Nieto F, Zeledon J, Pollard K, Tomich JM, and Fleming SD
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- Animals, Cell Line, Tumor, Cell Movement drug effects, Coculture Techniques, Dose-Response Relationship, Drug, Female, Melanoma, Experimental blood supply, Melanoma, Experimental metabolism, Mice, Peptides pharmacology, Phospholipids metabolism, Protein Domains, Tumor Microenvironment drug effects, Xenograft Model Antitumor Assays, beta 2-Glycoprotein I metabolism, Endothelial Cells cytology, Melanoma, Experimental drug therapy, Peptides administration & dosage, Vascular Endothelial Growth Factor Receptor-1 metabolism, beta 2-Glycoprotein I chemistry
- Abstract
Melanoma, a form of skin cancer, is one of the most common cancers in young men and women. Tumors require angiogenesis to provide oxygen and nutrients for growth. Pro-angiogenic molecules such as VEGF and anti-angiogenic molecules such as sFlt-1 control angiogenesis. In addition, the serum protein, Beta2 Glycoprotein I (β2-GPI) induces or inhibits angiogenesis depending on conformation and concentration. β2-GPI binds to proteins and negatively charged phospholipids on hypoxic endothelial cells present in the tumor microenvironment. We hypothesized that peptides derived from the binding domain of β2-GPI would regulate angiogenesis and melanoma growth. In vitro analyses determined the peptides reduced endothelial cell migration and sFlt-1 secretion. In a syngeneic, immunocompetent mouse melanoma model, β2-GPI-derived peptides also reduced melanoma growth in a dose-dependent response with increased sFlt-1 and attenuated vascular markers compared to negative controls. Importantly, administration of peptide with sFlt-1 antibody resulted in tumor growth. These data demonstrate the therapeutic potential of novel β2-GPI-derived peptides to attenuate tumor growth and endothelial migration is sFlt-1 dependent., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
- Full Text
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14. Eicosanoid production varies by sex in mesenteric ischemia reperfusion injury.
- Author
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Wu M, Rowe JM, and Fleming SD
- Subjects
- Animals, Complement C5a immunology, Cytokines immunology, Eicosanoids immunology, Female, Intestinal Mucosa immunology, Intestinal Mucosa pathology, Intestine, Small immunology, Intestine, Small pathology, Macrophages immunology, Male, Mice, Inbred C57BL, Neutrophil Infiltration, Peroxidase immunology, Reperfusion Injury pathology, Dinoprostone immunology, Leukotriene B4 immunology, Mesentery blood supply, Reperfusion Injury immunology, Sex Characteristics
- Abstract
Intestinal ischemia/reperfusion (I/R)-induced injury is an inflammatory response with significant morbidity and mortality. The early inflammatory response includes neutrophil infiltration. However, the majority of rodent studies utilize male mice despite a sexual dimorphism in intestinal I/R-related diseases. We hypothesized that sex may alter inflammation by changing neutrophil infiltration and eicosanoid production. To test this hypothesis, male and female C57Bl/6 mice were subjected to sham treatment or 30 min intestinal ischemia followed by a time course of reperfusion. We demonstrate that compared to male mice, females sustain significantly less intestinal I/R-induced tissue damage and produced significant LTB
4 concentrations. Male mice release PGE2 . Finally, treatment with a COX-2 specific inhibitor, NS-398, attenuated I/R-induced injury, total peroxidase level, and PGE2 production in males, but not in similarly treated female mice. Thus, I/R-induced eicosanoid production and neutrophil infiltration varies between sexes suggesting that distinct therapeutic intervention may be needed in clinical ischemic diseases., Competing Interests: Declaration of Competing Interest None of the authors has any potential financial conflict of interest related to this manuscript., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2020
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15. Essential Role of Complement in Pregnancy: From Implantation to Parturition and Beyond.
- Author
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Girardi G, Lingo JJ, Fleming SD, and Regal JF
- Subjects
- Complement System Proteins immunology, Female, Fetal Development immunology, Humans, Complement Activation immunology, Embryo Implantation immunology, Parturition immunology, Pregnancy immunology, Pregnancy Complications immunology
- Abstract
The complement cascade was identified over 100 years ago, yet investigation of its role in pregnancy remains an area of intense research. Complement inhibitors at the maternal-fetal interface prevent inappropriate complement activation to protect the fetus. However, this versatile proteolytic cascade also favorably influences numerous stages of pregnancy, including implantation, fetal development, and labor. Inappropriate complement activation in pregnancy can have adverse lifelong sequelae for both mother and child. This review summarizes the current understanding of complement activation during all stages of pregnancy. In addition, consequences of complement dysregulation during adverse pregnancy outcomes from miscarriage, preeclampsia, and pre-term birth are examined. Finally, future research directions into complement activation during pregnancy are considered., (Copyright © 2020 Girardi, Lingo, Fleming and Regal.)
- Published
- 2020
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16. A Study of the Cellular Uptake of Magnetic Branched Amphiphilic Peptide Capsules.
- Author
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Natarajan P, Roberts JD, Kunte N, Hunter WB, Fleming SD, Tomich JM, and Avila LA
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- Endocytosis physiology, Flow Cytometry, Microscopy, Confocal, Nanoparticles chemistry, Reactive Nitrogen Species metabolism, Reactive Oxygen Species metabolism, Peptides chemistry
- Abstract
Understanding cellular uptake mechanisms of nanoparticles with therapeutic potential has become critical in the field of drug delivery. Elucidation of cellular entry routes can aid in the dissection of the complex intracellular trafficking and potentially allow for the manipulation of nanoparticle fate after cellular delivery (i.e., avoid lysosomal degradation). Branched amphiphilic peptide capsules (BAPCs) are peptide nanoparticles that have been and are being explored as delivery systems for nucleic acids and other therapeutic molecules in vitro and in vivo. In the present study, we determined the cellular uptake routes of BAPCs with and without a magnetic nanobead core (BAPc-MNBs) in two cell lines: macrophages and intestinal epithelial cells. We also studied the influence of size and growth media composition in this cellular process. Substituting the water-filled core with magnetic nanobeads might provide the peptide bilayer nanocapsules with added functionalities, facilitating their use in bio/immunoassays, magnetic field guided drug delivery, and magnetofection among others. Results suggest that BAPc-MNBs are internalized into the cytosol using more than one endocytic pathway. Flow cytometry and analysis of reactive oxygen and nitrogen species (ROS/RNS) demonstrated that cell viability was minimally impacted by BAPc-MNBs. Cellular uptake pathways of peptide vesicles remain poorly understood, particularly with respect to endocytosis and intracellular trafficking. Outcomes from these studies provide a fundamental understanding of the cellular uptake of this peptide-based delivery system which will allow for strengthening of their delivery capabilities and expanding their applications both in vitro and in vivo.
- Published
- 2020
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17. Drivers and regulators of humoral innate immune responses to infection and cancer.
- Author
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Kumar D, Romero Y, Schuck KN, Smalley H, Subedi B, and Fleming SD
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- Antigens, Bacterial immunology, Antigens, Bacterial metabolism, Antigens, Neoplasm immunology, Antigens, Neoplasm metabolism, Antigens, Viral immunology, Antigens, Viral metabolism, Apoptosis immunology, B-Lymphocytes immunology, B-Lymphocytes metabolism, Complement Activation, Complement System Proteins immunology, Complement System Proteins metabolism, Humans, Immunoglobulin M immunology, Immunoglobulin M metabolism, Receptors, Complement immunology, Receptors, Complement metabolism, Tumor Escape, Bacterial Infections immunology, Immunity, Humoral, Immunity, Innate, Neoplasms immunology, Virus Diseases immunology
- Abstract
The complement cascade consists of cell bound and serum proteins acting together to protect the host from pathogens, remove cancerous cells and effectively links innate and adaptive immune responses. Despite its usefulness in microbial neutralization and clearance of cancerous cells, excessive complement activation causes an immune imbalance and tissue damage in the host. Hence, a series of complement regulatory proteins present at a higher concentration in blood plasma and on cell surfaces tightly regulate the cascade. The complement cascade can be initiated by B-1 B cell production of natural antibodies. Natural antibodies arise spontaneously without any known exogenous antigenic or microbial stimulus and protect against invading pathogens, clear apoptotic cells, provide tissue homeostasis, and modulate adaptive immune functions. Natural IgM antibodies recognize microbial and cancer antigens and serve as an activator of complement mediated lysis. This review will discuss advances in complement activation and regulation in bacterial and viral infections, and cancer. We will also explore the crosstalk of natural antibodies with bacterial populations and cancer., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
- Full Text
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18. Reply to "Letter to the Editor: Importance of B cells in response to placental ischemia".
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Regal JF, Laule CF, Root KM, Gilbert JS, and Fleming SD
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- B-Lymphocytes, Female, Humans, Ischemia, Placenta, Pregnancy, B-Lymphocyte Subsets, Hypertension
- Published
- 2020
- Full Text
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19. Interactions of viruses and the humoral innate immune response.
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Maloney BE, Perera KD, Saunders DRD, Shadipeni N, and Fleming SD
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- Animals, Humans, Immune Evasion immunology, Antibodies immunology, Blood Coagulation immunology, Complement Activation immunology, Immunity, Humoral immunology, Immunity, Innate immunology, Virus Diseases immunology, Viruses pathogenicity
- Abstract
The innate immune response is crucial for defense against virus infections where the complement system, coagulation cascade and natural antibodies play key roles. These immune components are interconnected in an intricate network and are tightly regulated to maintain homeostasis and avoid uncontrolled immune responses. Many viruses in turn have evolved to modulate these interactions through various strategies to evade innate immune activation. This review summarizes the current understanding on viral strategies to inhibit the activation of complement and coagulation cascades, evade natural antibody-mediated clearance and utilize complement regulatory mechanisms to their advantage., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
20. Interactions between the complement and endothelin systems in normal pregnancy and following placental ischemia.
- Author
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Regal JF, Lund JM, Wing CR, Root KM, McCutcheon L, Bemis LT, Gilbert JS, and Fleming SD
- Subjects
- Animals, Cell Line, Complement Activation immunology, Disease Models, Animal, Female, Pre-Eclampsia immunology, Pregnancy, Rats, Rats, Sprague-Dawley, Uterus immunology, Vascular Endothelial Growth Factor A immunology, Complement System Proteins immunology, Endothelins immunology, Ischemia immunology, Placenta immunology
- Abstract
Preeclampsia is characterized by new onset hypertension and fetal growth restriction and is associated with aberrant activation of the innate immune complement system and stressed or ischemic placenta. Previous studies have suggested a role for both endothelin and complement system activation products in new onset hypertension in pregnancy, but inter-relationships of the pathways are unclear. We hypothesized that complement activation following placental ischemia stimulates the endothelin pathway to cause hypertension and impair fetal growth. The Reduced Uterine Perfusion Pressure (RUPP) model results in hypertension and fetal growth restriction in a pregnant rat due to placental ischemia caused by mechanical obstruction of blood flow to uterus and placenta. The effect of inhibitor of complement activation soluble Complement Receptor 1 (sCR1) and endothelin A receptor (ET
A ) antagonist atrasentan on hypertension, fetal weight, complement activation (systemic circulating C3a and local C3 placental deposition) and endothelin [circulating endothelin and message for preproendothelin (PPE), ETA and endothelin B receptor (ETB) in placenta] in the RUPP rat model were determined. Following placental ischemia, sCR1 attenuated hypertension but increased message for PPE and ETA in placenta, suggesting complement activation causes hypertension via an endothelin independent pathway. With ETA antagonism the placental ischemia-induced increase in circulating C3a was unaffected despite inhibition of hypertension, indicating systemic C3a alone is not sufficient. In normal pregnancy, inhibiting complement activation increased plasma endothelin but not placental PPE message. Atrasentan treatment increased fetal weight, circulating endothelin and placental ETA message, and unexpectedly increased local complement activation in placenta (C3 deposition) but not C3a in circulation, suggesting endothelin controls local placental complement activation in normal pregnancy. Atrasentan also significantly decreased message for endogenous complement regulators Crry and CD55 in placenta and kidney in normal pregnancy. Results of our study indicate that complement/endothelin interactions differ in pregnancies complicated with placental ischemia vs normal pregnancy, as well as locally vs systemically. These data clearly illustrate the complex interplay between complement and endothelin indicating that perturbations of either pathway may affect pregnancy outcomes., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
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21. Role of B1 and B2 lymphocytes in placental ischemia-induced hypertension.
- Author
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Laule CF, Odean EJ, Wing CR, Root KM, Towner KJ, Hamm CM, Gilbert JS, Fleming SD, and Regal JF
- Subjects
- Animals, Antibodies, Monoclonal pharmacology, Antigens, CD20 immunology, B-Lymphocyte Subsets drug effects, B-Lymphocyte Subsets metabolism, Disease Models, Animal, Endothelin-1 metabolism, Female, Fetal Growth Retardation immunology, Fetal Growth Retardation physiopathology, Gestational Age, Immunoglobulin M blood, Lymphocyte Depletion, Pre-Eclampsia blood, Pre-Eclampsia physiopathology, Pregnancy, Rats, Sprague-Dawley, Arterial Pressure, B-Lymphocyte Subsets immunology, Placental Circulation, Pre-Eclampsia immunology
- Abstract
Preeclampsia is a prevalent pregnancy complication characterized by new-onset maternal hypertension and inflammation, with placental ischemia as the initiating event. Studies of others have provided evidence for the importance of lymphocytes in placental ischemia-induced hypertension; however, the contributions of B1 versus B2 lymphocytes are unknown. We hypothesized that peritoneal B1 lymphocytes are important for placental ischemia-induced hypertension. As an initial test of this hypothesis, the effect of anti-CD20 depletion on both B-cell populations was determined in a reduced utero-placental perfusion pressure (RUPP) model of preeclampsia. Anti-murine CD20 monoclonal antibody (5 mg/kg, Clone 5D2) or corresponding mu IgG2a isotype control was administered intraperitoneally to timed pregnant Sprague-Dawley rats on gestation day (GD)10 and 13. RUPP or sham control surgeries were performed on GD14, and mean arterial pressure (MAP) was measured on GD19 from a carotid catheter. As anticipated, RUPP surgery increased MAP and heart rate and decreased mean fetal and placental weight. However, anti-CD20 treatment did not affect these responses. On GD19, B-cell populations were enumerated in the blood, peritoneal cavity, spleen, and placenta with flow cytometry. B1 and B2 cells were not significantly increased following RUPP. Anti-CD20 depleted B1 and B2 cells in peritoneum and circulation but depleted only B2 lymphocytes in spleen and placenta, with no effect on circulating or peritoneal IgM. Overall, these data do not exclude a role for antibodies produced by B cells before depletion but indicate the presence of B lymphocytes in the last trimester of pregnancy is not critical for placental ischemia-induced hypertension. NEW & NOTEWORTHY The adaptive and innate immune systems are implicated in hypertension, including the pregnancy-specific hypertensive condition preeclampsia. However, the mechanism of immune system dysfunction leading to pregnancy-induced hypertension is unresolved. In contrast to previous reports, this study reveals that the presence of classic B2 lymphocytes and peritoneal and circulating B1 lymphocytes is not required for development of hypertension following third trimester placental ischemia in a rat model of pregnancy-induced hypertension.
- Published
- 2019
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22. Proteomic analysis reveals greater abundance of complement and inflammatory proteins in subcutaneous adipose tissue from postpartum cows treated with sodium salicylate.
- Author
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Takiya CS, Montgomery SR, Mamedova LK, Kra G, Nemes-Navon N, Levin Y, Fleming SD, Bradford BJ, and Zachut M
- Subjects
- Animals, Cattle, Female, Complement System Proteins metabolism, Postpartum Period metabolism, Proteomics, Sodium Salicylate pharmacology, Subcutaneous Fat metabolism
- Abstract
This study aimed to investigate sodium salicylate (SS) treatment effects on the proteome of adipose tissue (AT) in postpartum cows. Twenty Holstein cows were assigned to control (CON, n = 10) or SS (n = 10) provided via drinking water (2.3 g/L) during the first 7 d of lactation. Subcutaneous AT was collected on d 7 of treatment and label-free quantitative shotgun proteomics and immunoblotting were analyzed in a subset of 5 AT per group. Eighty out of 1422 proteins (5.6%) were differentially abundant between CON and SS [fold change ±1.5, P < 0.05]. Top canonical pathways differing between CON and SS (Ingenuity) were complement system, interleukin-10 signaling, and acute phase response signaling. The abundances of complement C1r, C1qC, C1qB and C6 were greater in SS than CON. Regarding IL-10 signaling, the abundances of BLVRB, STAT3, and lipopolysaccharide binding protein (LBP) were greater in SS AT compared to CON. Immunoblots revealed increased abundance of paraoxanase-1 and tumor necrosis factor-alpha, as well as a tendency for greater abundance of cluster differentiation 172a in SS AT, which may indicate of increased macrophage infiltration. SS treatment postpartum likely promotes inflammatory signaling in AT of dairy cows, perhaps due to immune cell recruitment. SIGNIFICANCE: This work demonstrates that treating early lactating cows with sodium salicylate, an anti-inflammatory agent that has been shown to have metabolic effects and increase milk production in dairy cows, affects the proteome of subcutaneous adipose tissue in early lactating dairy cows. Unexpectedly, sodium salicylate treatment enriched inflammatory pathways of the complement system, cytokine signaling, and acute phase response, as revealed by proteomic analysis of subcutaneous adipose tissues from cows at 7 d postpartum. These findings imply that SS treatment during the first 7 d of lactation likely promotes inflammatory signaling in AT of the dairy cow, perhaps due to immune cell recruitment. Tissue-specific impacts of systemic sodium salicylate requires further scrutiny., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
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23. Transforming Growth Factor Beta Signaling in Dendritic Cells Is Required for Immunotolerance to Sperm in the Epididymis.
- Author
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Pierucci-Alves F, Midura-Kiela MT, Fleming SD, Schultz BD, and Kiela PR
- Subjects
- Animals, Autoantibodies immunology, Autoimmunity, Gene Expression Profiling, Immunohistochemistry, Leukocytosis, Male, Mice, Mice, Transgenic, Sperm Maturation genetics, Sperm Maturation immunology, Spermatozoa cytology, Transcriptome, Dendritic Cells immunology, Dendritic Cells metabolism, Epididymis immunology, Epididymis metabolism, Immune Tolerance, Signal Transduction, Spermatozoa immunology, Spermatozoa metabolism, Transforming Growth Factor beta metabolism
- Abstract
The epididymis exhibits a less restrictive physical blood-tissue barrier than the testis and, while numerous immunosuppressive factors have been identified in the latter, no mechanisms for epididymal immunotolerance have been identified to date. Therefore, data are currently insufficient to explain how the immune system tolerates the extremely large load of novel antigens expressed on sperm, which become present in the male body after puberty, i.e., long after central tolerance was established. This study tested the hypothesis that transforming growth factor beta (TGFβ) signaling in dendritic cells (DCs) is required for immunotolerance to sperm located in the epididymis, and that male mice lacking TGFβ signaling in DCs would develop severe epididymal inflammation. To test this, we employed adult Tgfbr2
ΔDC males, which exhibit a significant reduction of Tgfbr 2 expression and TGFβ signaling in DCs, as reported previously. Results show that Tgfbr2ΔDC males exhibit sperm-specific immune response and severe epididymal leukocytosis. This phenotype is consistent with epididymal loss of immunotolerance to sperm and suggests that TGFβ signaling in DCs is a factor required for a non-inflammatory steady state in the epididymis, and therefore for male tract homeostasis and function.- Published
- 2018
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24. The Complement System and Preeclampsia.
- Author
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Regal JF, Burwick RM, and Fleming SD
- Subjects
- Animals, Complement C5a physiology, Complement Membrane Attack Complex physiology, Disease Models, Animal, Endothelium, Vascular physiopathology, Female, Fetal Growth Retardation physiopathology, Homeostasis, Humans, Hypertension physiopathology, Mice, Neovascularization, Pathologic physiopathology, Pregnancy, Proteinuria physiopathology, Rats, Complement Activation physiology, Placenta physiopathology, Pre-Eclampsia physiopathology
- Abstract
Purpose of Review: Preeclampsia affects 3-4% of pregnancies with few treatment options to reduce maternal and fetal harm. Recent evidence that targeting the complement system may be an effective therapeutic strategy in prevention or treatment of preeclampsia will be reviewed., Recent Findings: Studies in humans confirm the safety and efficacy of C5 blockade in complement-mediated disorders of pregnancy, including preeclampsia. Animal models mimic the placental abnormalities and/or the maternal symptoms which characterize preeclampsia. These models in mouse and rat have defined a role for complement and its regulators in placental dysfunction, hypertension, proteinuria, endothelial dysfunction, fetal growth restriction, and angiogenic imbalance, thus informing future human studies. Targeting excessive complement activation, particularly the terminal complement complex (C5b-9) and C5a may be an effective strategy to prolong pregnancy in women with preeclampsia. Continued research is needed to identify the initiator(s) of activation, the pathways involved, and the key component(s) in the pathophysiology to allow development of safe and effective therapeutics to target complement without compromising its role in homeostasis and host defense.
- Published
- 2017
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25. Overexpression of eIF5 or its protein mimic 5MP perturbs eIF2 function and induces ATF4 translation through delayed re-initiation.
- Author
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Kozel C, Thompson B, Hustak S, Moore C, Nakashima A, Singh CR, Reid M, Cox C, Papadopoulos E, Luna RE, Anderson A, Tagami H, Hiraishi H, Slone EA, Yoshino KI, Asano M, Gillaspie S, Nietfeld J, Perchellet JP, Rothenburg S, Masai H, Wagner G, Beeser A, Kikkawa U, Fleming SD, and Asano K
- Subjects
- Animals, Carcinogenesis pathology, Cell Line, Tumor, Drosophila melanogaster metabolism, Eukaryotic Initiation Factor-3, Fibrosarcoma pathology, Gene Knockdown Techniques, HEK293 Cells, HeLa Cells, Humans, Male, Mass Spectrometry, Mice, Nude, Activating Transcription Factor 4 metabolism, DNA-Binding Proteins metabolism, Eukaryotic Initiation Factor-2 metabolism, Eukaryotic Initiation Factor-5 metabolism, Peptide Chain Initiation, Translational
- Abstract
ATF4 is a pro-oncogenic transcription factor whose translation is activated by eIF2 phosphorylation through delayed re-initiation involving two uORFs in the mRNA leader. However, in yeast, the effect of eIF2 phosphorylation can be mimicked by eIF5 overexpression, which turns eIF5 into translational inhibitor, thereby promoting translation of GCN4, the yeast ATF4 equivalent. Furthermore, regulatory protein termed eIF5-mimic protein (5MP) can bind eIF2 and inhibit general translation. Here, we show that 5MP1 overexpression in human cells leads to strong formation of 5MP1:eIF2 complex, nearly comparable to that of eIF5:eIF2 complex produced by eIF5 overexpression. Overexpression of eIF5, 5MP1 and 5MP2, the second human paralog, promotes ATF4 expression in certain types of human cells including fibrosarcoma. 5MP overexpression also induces ATF4 expression in Drosophila The knockdown of 5MP1 in fibrosarcoma attenuates ATF4 expression and its tumor formation on nude mice. Since 5MP2 is overproduced in salivary mucoepidermoid carcinoma, we propose that overexpression of eIF5 and 5MP induces translation of ATF4 and potentially other genes with uORFs in their mRNA leaders through delayed re-initiation, thereby enhancing the survival of normal and cancer cells under stress conditions., (© The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2016
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26. Role of IgM and angiotensin II Type I receptor autoantibodies in local complement activation in placental ischemia-induced hypertension in the rat.
- Author
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Regal JF, Strehlke ME, Peterson JM, Wing CR, Parker JE, Nieto NF, Bemis LT, Gilbert JS, and Fleming SD
- Subjects
- Animals, Autoantigens immunology, Disease Models, Animal, Female, Immunoglobulin M, Immunohistochemistry, Ischemia complications, Placenta blood supply, Pre-Eclampsia physiopathology, Pregnancy, Rats, Rats, Sprague-Dawley, Real-Time Polymerase Chain Reaction, Autoantibodies immunology, Complement Activation immunology, Hypertension immunology, Pre-Eclampsia immunology, Receptor, Angiotensin, Type 1 immunology
- Abstract
Preeclampsia is characterized by development of hypertension during pregnancy and reduced placental perfusion. Previous studies in a rat model of placental ischemia-induced hypertension demonstrated that inhibiting complement activation attenuated increased maternal blood pressure with C3a and C5a identified as the important products of complement activation. Given that in other forms of ischemia both natural IgM and antigen antibody complexes initiate complement activation, we hypothesized that placental ischemia exposes neoepitopes recognized by IgM to cause local complement activation and hypertension. Alternatively, we postulated that autoantibody to angiotensin II Type 1 receptor (AT1-AA) interacts with AT1 receptors to cause complement activation. Since complement activation occurs in kidney and placenta in preeclampsia, we used immunohistochemistry to determine IgM deposition and local complement activation in each organ (C3 deposition), and quantitative real-time polymerase chain reaction (qRT-PCR) to quantitate mRNA for endogenous regulators of complement activation CD55, CD59 and Complement receptor 1-related gene/protein y (Crry). On gestation day (GD)14.5, timed pregnant Sprague Dawley rats underwent Sham surgery or placement of clips on inferior abdominal aorta and ovarian arteries to create placental ischemia using the reduced utero-placental perfusion pressure (RUPP) model. As previously reported, RUPP surgery increased mean arterial pressure and circulating C3a on GD19.5. In placenta, IgM and C3 deposition increased, whereas mRNA for complement regulators Crry and CD59 decreased along with Crry protein in RUPP compared to Sham treated animals. In kidney, IgM deposition increased in animals subjected to RUPP vs Sham surgery without a significant change in C3 deposition and coincident with an increase in mRNA for CD55 and CD59. The AT1 receptor antagonist losartan prevents placental ischemia-induced hypertension as well as AT1-AA interaction with AT1 receptors. However, losartan did not attenuate complement activation as measured by circulating C3a or placental C3 deposition. Importantly, our studies indicate that following placental ischemia, complement activation is not due to AT1-AA but is associated with IgM deposition. These studies suggest a role for natural antibodies interacting with placental ischemia-induced neoepitopes to activate complement and contribute to hypertension., Competing Interests: or Conflict of Interest The authors have no conflicts to report, (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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27. Radiotherapy: killing with complement.
- Author
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Regal JF, Dornfeld KJ, and Fleming SD
- Published
- 2016
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28. TLR2 Regulates Complement-Mediated Inflammation Induced by Blood Loss During Hemorrhage.
- Author
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Goering J, Pope MR, and Fleming SD
- Subjects
- Animals, Complement Activation immunology, Inflammation etiology, Inflammation pathology, Intestines blood supply, Intestines pathology, Male, Mice, Inbred C57BL, Mice, Knockout, Regional Blood Flow, Shock, Hemorrhagic complications, Toll-Like Receptor 2 deficiency, Complement System Proteins immunology, Inflammation immunology, Inflammation Mediators immunology, Shock, Hemorrhagic immunology, Toll-Like Receptor 2 immunology
- Abstract
Hemorrhagic shock resulting from blood loss directs the majority of the blood to the vital organs, dramatically reducing blood flow to the intestines and resulting in damage and inflammation. The excessive intestinal inflammatory response includes pro-inflammatory cytokines and complement activation, although the mechanism is not clear. Toll-like receptors play a vital role in the innate immune response and toll-like receptor 2 (TLR2) is required for intestinal ischemia/reperfusion-induced injury. We hypothesized that TLR2 plays an integral role in the intestinal inflammatory response after hemorrhage and subjected C57Bl/6 wild-type and Tlr2(-/-) mice to atraumatic loss of ∼30% total blood volume. Two hours after blood removal, the intestinal injury and inflammation were assessed. We demonstrate that compared with wild-type control mice, Tlr2(-/-) mice sustain less intestinal damage and inflammation. Importantly, TLR2 regulated eicosanoid and complement activation and IL-12 and TNFα secretions, indicating interactions between TLR2 and complement in response to significant blood loss.
- Published
- 2016
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29. Phospholipid scramblase 1 is required for β2-glycoprotein I binding in hypoxia and reoxygenation-induced endothelial inflammation.
- Author
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Slone EA, Pope MR, and Fleming SD
- Subjects
- Animals, Cell Hypoxia, Cell Line, Endothelium, Vascular pathology, Immunoglobulin M genetics, Immunoglobulin M metabolism, Inflammation genetics, Inflammation metabolism, Inflammation pathology, Mice, Phospholipid Transfer Proteins genetics, Reperfusion Injury genetics, Reperfusion Injury pathology, Vasculitis genetics, Vasculitis pathology, beta 2-Glycoprotein I genetics, Endothelium, Vascular metabolism, Phospholipid Transfer Proteins metabolism, Reperfusion Injury metabolism, Vasculitis metabolism, beta 2-Glycoprotein I metabolism
- Abstract
Multiple pathologic conditions, including hemorrhage, tumor angiogenesis, and ischemia-reperfusion events, will result in hypoxia and subsequent reperfusion. Previous studies have analyzed the lipid changes within whole tissues and indicated that ischemia-reperfusion altered tissue and cellular phospholipids. Using an in vitro cell culture model of hypoxia and reoxygenation, we examined the endothelial lipid changes. We hypothesized that phospholipid scramblase 1, a protein that regulates bilayer asymmetry, is involved in altering the phospholipids of endothelial cells during hypoxia, a component of ischemia, leading to β2-glycoprotein I and IgM binding and subsequent lipid-mediated, inflammatory responses. We have completed the first comprehensive study of steady-state phospholipid scramblase 1 mRNA levels, protein expression, and activity under conditions of hypoxia and reoxygenation. Phospholipid scramblase 1 regulates phosphatidylserine exposure in response to oxygen stress, leading to β2-glycoprotein I and IgM binding and lipid-mediated, inflammatory responses., (© Society for Leukocyte Biology.)
- Published
- 2015
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30. Evasion and interactions of the humoral innate immune response in pathogen invasion, autoimmune disease, and cancer.
- Author
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Rettig TA, Harbin JN, Harrington A, Dohmen L, and Fleming SD
- Subjects
- Antibodies immunology, Cohort Studies, Complement System Proteins immunology, Humans, Autoimmune Diseases immunology, Gram-Positive Bacterial Infections immunology, Immune Evasion immunology, Immunity, Humoral immunology, Immunity, Innate immunology, Neoplasms immunology, Tumor Escape immunology, Virus Diseases immunology
- Abstract
The humoral innate immune system is composed of three major branches, complement, coagulation, and natural antibodies. To persist in the host, pathogens, such as bacteria, viruses, and cancers must evade parts of the innate humoral immune system. Disruptions in the humoral innate immune system also play a role in the development of autoimmune diseases. This review will examine how Gram positive bacteria, viruses, cancer, and the autoimmune conditions systemic lupus erythematosus and anti-phospholipid syndrome, interact with these immune system components. Through examining evasion techniques it becomes clear that an interplay between these three systems exists. By exploring the interplay and the evasion/disruption of the humoral innate immune system, we can develop a better understanding of pathogenic infections, cancer, and autoimmune disease development., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
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31. TLR2 modulates antibodies required for intestinal ischemia/reperfusion-induced damage and inflammation.
- Author
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Pope MR and Fleming SD
- Subjects
- Animals, Antibodies blood, Complement System Proteins immunology, Cytokines biosynthesis, Disease Models, Animal, Eicosanoids biosynthesis, Immunoglobulin M blood, Immunoglobulin M immunology, Inflammation genetics, Inflammation pathology, Intestinal Mucosa immunology, Intestinal Mucosa pathology, Intestines pathology, Mice, Mice, Knockout, Reperfusion Injury genetics, Toll-Like Receptor 2 genetics, beta 2-Glycoprotein I immunology, beta 2-Glycoprotein I metabolism, Antibodies immunology, Inflammation immunology, Inflammation metabolism, Intestinal Mucosa metabolism, Intestines immunology, Reperfusion Injury immunology, Reperfusion Injury metabolism, Toll-Like Receptor 2 metabolism
- Abstract
In multiple clinical conditions, including trauma and hemorrhage, reperfusion magnifies ischemic tissue damage. Ischemia induces expression of multiple neoantigens, including lipid alterations that are recognized by the serum protein, β2-glycoprotein I (β2-GPI). During reperfusion, binding of β2-GPI by naturally occurring Abs results in an excessive inflammatory response that may lead to death. As β2-GPI is critical for intestinal ischemia/reperfusion (IR)-induced tissue damage and TLR2 is one of the proposed receptors for β2-GPI, we hypothesized that IR-induced intestinal damage and inflammation require TLR2. Using TLR2(-/-) mice, we demonstrate that TLR2 is required for IR-induced mucosal damage, as well as complement activation and proinflammatory cytokine production. In response to IR, TLR2(-/-) mice have increased serum β2-GPI compared with wild-type mice, but β2-GPI is not deposited on ischemic intestinal tissue. In addition, TLR2(-/-) mice also did not express other novel Ags, suggesting a sequential response. Unlike other TLRs, TLR2(-/-) mice lacked the appropriate Ab repertoire to induce intestinal IR tissue damage or inflammation. Together, these data suggest that, in addition to the inflammatory response, IR-induced injury requires TLR2 for naturally occurring Ab production., (Copyright © 2015 by The American Association of Immunologists, Inc.)
- Published
- 2015
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32. Membrane lipid interactions in intestinal ischemia/reperfusion-induced Injury.
- Author
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Slone EA and Fleming SD
- Subjects
- Animals, Antibodies immunology, Antigens immunology, Humans, Hypoxia metabolism, Intestines blood supply, Intestines immunology, Phospholipid Transfer Proteins metabolism, Reperfusion Injury immunology, Signal Transduction, Intestinal Mucosa metabolism, Intestines pathology, Membrane Lipids metabolism, Reperfusion Injury metabolism
- Abstract
Ischemia, lack of blood flow, and reperfusion, return of blood flow, are a common phenomenon affecting millions of Americans each year. Roughly 30,000 Americans per year experience intestinal ischemia-reperfusion (IR), which is associated with a high mortality rate. Previous studies of the intestine established a role for neutrophils, eicosanoids, the complement system and naturally occurring antibodies in IR-induced pathology. Furthermore, data indicate involvement of a lipid or lipid-like moiety in mediating IR-induced damage. It has been proposed that antibodies recognize exposure of neo-antigens, triggering action of the complement cascade. While it is evident that the pathophysiology of IR-induced injury is complex and multi-factorial, we focus this review on the involvement of eicosanoids, phospholipids and neo-antigens in the early pathogenesis. Lipid changes occurring in response to IR, neo-antigens exposed and the role of a phospholipid transporter, phospholipid scramblase 1 will be discussed., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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33. Bone marrow leptin signaling mediates obesity-associated adipose tissue inflammation in male mice.
- Author
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Dib LH, Ortega MT, Fleming SD, Chapes SK, and Melgarejo T
- Subjects
- Animal Feed, Animals, Body Composition, Diet, High-Fat, Disease Models, Animal, Gene Expression Profiling, Immunohistochemistry, Inflammation, Macrophages metabolism, Male, Mice, Mice, Inbred C57BL, Obesity metabolism, Receptors, Leptin metabolism, Signal Transduction, Adipose Tissue metabolism, Bone Marrow metabolism, Gene Expression Regulation, Leptin metabolism, Receptors, Leptin genetics
- Abstract
Obesity is characterized by an increased recruitment of proinflammatory macrophages to the adipose tissue (AT), leading to systemic inflammation and metabolic disease. The pathogenesis of this AT inflammation, however, remains to be elucidated. The circulating adipokine leptin is increased in obesity and is involved in immune cell function and activation. In the present study, we investigated the role of leptin in the induction of obesity-associated inflammation. We generated radiation chimeric C57BL/6J mice reconstituted with either leptin receptor-deficient (db/db) or wild-type (WT) bone marrow and challenged them with a high-fat diet (HFD) for 16 weeks. Mice reconstituted with db/db bone marrow (WT/db), had significantly lower body weight and adiposity compared with mice with WT bone marrow (WT/WT). Gonadal AT in WT/db mice displayed a 2-fold lower expression of the inflammatory genes Tnfa, Il6, and Ccl2. In addition, gonadal fat of WT/db mice contained significantly fewer crown-like structures compared with WT/WT mice, and most of their AT macrophages expressed macrophage galactose-type C type lectin 1 (MGL1) and were C-C chemokine receptor type 2 (CCR2)-negative, indicative of an anti-inflammatory phenotype. Moreover, WT/db mice exhibited greater insulin sensitivity compared with WT/WT mice. These data show that disrupted leptin signaling in bone marrow-derived cells attenuates the proinflammatory conditions that mediate many of the metabolic complications that characterize obesity. Our findings establish a novel mechanism involved in the regulation of obesity-associated systemic inflammation and support the hypothesis that leptin is a proinflammatory cytokine.
- Published
- 2014
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34. Normal live births after intracytoplasmic sperm injection in a man with the rare condition of Eagle-Barrett syndrome (prune-belly syndrome).
- Author
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Fleming SD, Varughese E, Hua VK, Robertson A, Dalzell F, and Boothroyd CV
- Subjects
- Female, Humans, In Vitro Techniques, Infant, Newborn, Male, Pregnancy, Treatment Outcome, Infertility genetics, Infertility therapy, Live Birth, Prune Belly Syndrome genetics, Prune Belly Syndrome therapy, Sperm Injections, Intracytoplasmic methods
- Abstract
Objective: To report the first live births of male infants resulting from intracytoplasmic sperm injection (ICSI) using spermatozoa from a man with Eagle-Barrett syndrome (EBS)., Design: Case report., Setting: Assisted conception unit within a private hospital., Patient(s): An infertile couple., Interventions: An infertile couple received repeated treatment with ICSI., Main Outcome Measure(s): Clinical pregnancy and a normal live birth., Result(s): In 2008, after microinjection of ten oocytes, the transfer of a single expanded blastocyst led to the premature birth of a morphologically normal male infant at 18 weeks' gestation. This outcome followed preterm rupture of membranes and possible cervical incompetence. In 2009, after microinjection of six oocytes, transfer of a single 5-cell embryo led to a singleton pregnancy, with emergency cervical cerclage being performed at 21 weeks. A healthy male infant was born at 30 weeks, with no evidence of EBS, by lower-segment cesarean section for breech presentation and premature labor. In 2012, after elective laparoscopic placement of cervical suture, microinjection of ten oocytes and transfer of a single 4-cell embryo led to a singleton pregnancy with a healthy male infant, with no evidence of EBS, being born by cesarean section at 38 weeks., Conclusion(s): This report suggests that EBS is not transmitted to male offspring via ICSI., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.)
- Published
- 2013
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35. Toll-like receptor 4 signaling is required for induction of gluconeogenic gene expression by palmitate in human hepatic carcinoma cells.
- Author
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Mamedova LK, Yuan K, Laudick AN, Fleming SD, Mashek DG, and Bradford BJ
- Subjects
- Cell Line, Tumor, Cyclic AMP Response Element-Binding Protein genetics, Cyclic AMP Response Element-Binding Protein metabolism, Glucose-6-Phosphatase genetics, Glucose-6-Phosphatase metabolism, Hep G2 Cells, Hepatocytes drug effects, Hepatocytes metabolism, Humans, Intracellular Signaling Peptides and Proteins genetics, Intracellular Signaling Peptides and Proteins metabolism, Lipid A adverse effects, Lipid A analogs & derivatives, Lipopolysaccharides adverse effects, Liver Neoplasms metabolism, Phosphoenolpyruvate Carboxykinase (GTP) genetics, Phosphoenolpyruvate Carboxykinase (GTP) metabolism, Promoter Regions, Genetic, RNA, Messenger genetics, RNA, Messenger metabolism, Reproducibility of Results, Signal Transduction, Toll-Like Receptor 4 genetics, Up-Regulation, Fatty Acids, Nonesterified adverse effects, Gene Expression, Gluconeogenesis genetics, Palmitates adverse effects, Toll-Like Receptor 4 metabolism
- Abstract
Saturated free fatty acids (FFA) can activate inflammatory cascades including the toll-like receptor 4 (TLR4) pathway. TLR4 is expressed by hepatocytes and may help link FFA to altered hepatic gluconeogenesis in type 2 diabetes mellitus. This study examined the role of TLR4 in mediating palmitate effects on the expression of phosphoenolpyruvate carboxykinase (PCK1) and the catalytic subunit of glucose-6-phosphatase (G6PC), rate-determining gluconeogenic enzymes. Human hepatocellular carcinoma cells (HepG2 and HuH7) were incubated in media including 2% bovine serum albumin and 250 to 1000 μM palmitate for 24 h. Signaling mediated by TLR4 was blocked by a TLR4 decoy peptide or small interfering RNA knockdown of TLR4. Palmitate induced dose-dependent increases in PCK1 and G6PC mRNA abundance, which were prevented by the TLR4 decoy peptide. Palmitate doubled PCK1 promoter activity, and TLR4 knockdown ablated this response. Lipopolysaccharide and monophosphoryl lipid A also up-regulated G6PC and PCK1 transcript abundance in a TLR4-dependent manner. Addition of oleate attenuated palmitate-induced increases in G6PC and PCK1 mRNA abundance. Palmitate increased nuclear factor κ-light-chain-enhancer of activated B cells reporter gene activity, which was unaffected by TLR4 blockade, but increased mRNA abundance of hepatocyte-specific cyclic AMP response element binding protein, a transcriptional regulator of PCK1, in a TLR4-dependent manner. Finally, TLR4 activation by palmitate increased subsequent cellular uptake of palmitate, and inhibiting ceramide synthesis ablated palmitate effects on PCK1 mRNA abundance and promoter activity. These results suggest that TLR4 signaling could play a critical role in linking elevated saturated FFA to increased transcription of gluconeogenic genes., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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36. Small β2-glycoprotein I peptides protect from intestinal ischemia reperfusion injury.
- Author
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Pope MR, Bukovnik U, Tomich JM, and Fleming SD
- Subjects
- Animals, Disease Models, Animal, Endothelium, Vascular immunology, Endothelium, Vascular pathology, Inflammation immunology, Inflammation pathology, Inflammation prevention & control, Intestines pathology, Mice, Peptides immunology, Protein Structure, Tertiary, Reperfusion Injury pathology, Time Factors, beta 2-Glycoprotein I immunology, Intestines immunology, Peptides pharmacology, Reperfusion Injury immunology, Reperfusion Injury prevention & control, beta 2-Glycoprotein I pharmacology
- Abstract
Intestinal ischemic events, which are followed by reperfusion, induce significant tissue damage and frequently result in multiple organ failure, with >70% mortality. Upon reperfusion, excessive inflammation leads to exacerbated tissue damage. Previous studies indicated that binding of the serum protein, β2-glycoprotein I, to the endothelium initiates a cascade of inflammatory molecules that is required for damage. We hypothesized that peptides derived from the binding domain (domain V) of β2-glycoprotein I would attenuate ischemia/reperfusion-induced damage and inflammation in a therapeutic manner. Using a mouse model of intestinal ischemia/reperfusion, we administered peptides either prior to ischemia or at clinically relevant time points during reperfusion and evaluated intestinal tissue damage and inflammation after 2 h of reperfusion. We demonstrate that multiple peptides attenuate injury and inflammation in a dose-dependent manner and, perhaps more significantly, are efficacious when administered up to 30 min after the onset of reperfusion. In addition, an all D-amino acid retro-inverso peptide was biologically active. Thus, the β2-glycoprotein I-derived peptides attenuate injury and inflammation when administered in a therapeutic manner in intestinal ischemia/reperfusion injury.
- Published
- 2012
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37. Human β2-glycoprotein I attenuates mouse intestinal ischemia/reperfusion induced injury and inflammation.
- Author
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Tomasi M, Hiromasa Y, Pope MR, Gudlur S, Tomich JM, and Fleming SD
- Subjects
- Amino Acid Sequence, Animals, Cell Membrane metabolism, Dinoprostone biosynthesis, Homeodomain Proteins genetics, Humans, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Knockout, Protein Structure, Secondary, Proteomics, Reperfusion Injury drug therapy, Sequence Alignment, beta 2-Glycoprotein I metabolism, Inflammation immunology, Intestines immunology, Reperfusion Injury immunology, beta 2-Glycoprotein I chemistry, beta 2-Glycoprotein I immunology
- Abstract
Intestinal ischemia-reperfusion (IR)-induced injury results from a complex cascade of inflammatory components. In the mouse model of intestinal IR, the serum protein, β2-glycoprotein I (β2-GPI) binds to the cell surface early in the cascade. The bound β2-GPI undergoes a conformational change which exposes a neoantigen recognized by naturally occurring antibodies and initiates the complement cascade. We hypothesized that providing additional antigen with exogenous β2-GPI would alter IR-induced tissue injury. Administration of human but not mouse β2-GPI attenuated IR-induced tissue damage and prostaglandin E(2) production indicating a physiological difference between β2-GPI isolated from the two species. To investigate whether structural features were responsible for this physiological difference, we compared the chemical, physical and biochemical properties of the two proteins. Despite possessing 76% amino acid identity and 86% sequence homology, we found that mouse β2-GPI differs from the human protein in size, carbohydrate chain location, heterogeneity and secondary structural content. These data suggest that the structural differences result in mouse Ab recognition of soluble human but not mouse β2-GPI and attenuated IR-induced injury. We conclude that caution should be exercised in interpreting results obtained by using human β2-GPI in a mouse model., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2012
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38. Humoral innate immune response and disease.
- Author
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Shishido SN, Varahan S, Yuan K, Li X, and Fleming SD
- Subjects
- Animals, Atherosclerosis immunology, Chronic Disease, Humans, Infections immunology, Neoplasms immunology, Immunity, Humoral, Immunity, Innate
- Abstract
The humoral innate immune response consists of multiple components, including the naturally occurring antibodies (NAb), pentraxins and the complement and contact cascades. As soluble, plasma components, these innate proteins provide key elements in the prevention and control of disease. However, pathogens and cells with altered self proteins utilize multiple humoral components to evade destruction and promote pathology. Many studies have examined the relationship between humoral immunity and autoimmune disorders. This review focuses on the interactions between the humoral components and their role in promoting the pathogenesis of bacterial and viral infections and chronic diseases such as atherosclerosis and cancer. Understanding the beneficial and detrimental aspects of the individual components and the interactions between proteins which regulate the innate and adaptive response will provide therapeutic targets for subsequent studies., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
39. Naturally occurring autoantibodies mediate ischemia/reperfusion-induced tissue injury.
- Author
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Fleming SD
- Subjects
- Animals, Autoantigens immunology, Complement Activation immunology, Complement System Proteins immunology, Humans, Immunity, Innate, Immunoglobulins, Intravenous immunology, Immunoglobulins, Intravenous therapeutic use, Mice, Mice, Knockout, Reperfusion Injury immunology, Ribonucleoprotein, U1 Small Nuclear immunology, beta 2-Glycoprotein I immunology, Antibodies, Antiphospholipid immunology, Autoantibodies immunology, Reperfusion Injury prevention & control
- Abstract
Ischemia and reperfusion events within the heart and brain and similar trauma-induced ischemia/reperfusion events lead to significant morbidity and mortality. In the past two decades, an excessive innate immune response has been identified as the mediator of reperfusion-induced tissue damage. Recent evidence indicates that naturally occurring autoantibody (NAb) activation of complement is a major mechanism of injury due to ischemia/reperfusion. This chapter focuses on the antigens exposed by ischemia and recognized by NAbs, the mechanism of complement activation by damaging NAbs and the protective role of IVIG in ischemia/reperfusion-induced pathology.
- Published
- 2012
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- View/download PDF
40. TLR9 is dispensable for intestinal ischemia/reperfusion-induced tissue damage.
- Author
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Slone EA, Pope MR, Roth M, Welti R, and Fleming SD
- Abstract
The mortality rate due to intestinal ischemia/reperfusion (IR) remains at 60-80%. As toll-like receptor (TLR) 4 has been shown to be critical for IR injury in several organs, including the intestine, and TLR9 is necessary for IR-induced damage of the liver, we investigated the hypothesis that TLR9 is involved in intestinal IR-induced damage. Wildtype (C57Bl/6) and TLR9(-/-) mice were subjected to intestinal IR or Sham treatment. Several markers of damage and inflammation were assessed, including mucosal injury, eicosanoid production, cytokine secretion and complement deposition. Although IR-induced injury was not altered, PGE(2) production was decreased in TLR9(-/-) mice. Attenuated PGE(2) production was not due to differences in percentage of lipids or COX-2 transcription. The data indicate that TLR9 is not required for IR-induced injury or inflammation of the intestine.
- Published
- 2012
41. Helicobacter infection alters MyD88 and Trif signalling in response to intestinal ischaemia-reperfusion.
- Author
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Hoffman SM, Wang H, Pope MR, and Fleming SD
- Subjects
- Animals, Mice, Mice, Inbred C57BL, Mice, Knockout, Adaptor Proteins, Vesicular Transport metabolism, Helicobacter Infections metabolism, Intestinal Diseases metabolism, Myeloid Differentiation Factor 88 metabolism, Reperfusion Injury metabolism, Signal Transduction
- Abstract
Ischaemia-reperfusion-induced intestinal injury requires both Toll-like receptor 4 (TLR4) signalling through myeloid differentiation primary response gene (88) (MyD88) and complement activation. As a common Gram-negative intestinal pathogen, Helicobacter hepaticus signals through TLR4 and upregulates the complement inhibitor, decay accelerating factor (DAF; CD55). Since ischaemia-reperfusion (IR) injury is complement dependent, we hypothesized that Helicobacter infection may alter IR-induced intestinal damage. Infection increased DAF transcription and subsequently decreased complement activation in response to IR without altering intestinal damage in wild-type mice. Ischaemia-reperfusion induced similar levels of DAF mRNA expression in uninfected wild-type, MyD88(-/-) or TIR-domain-containing adaptor-inducing interferon-β (Trif)-deficient mice. However, during infection, IR-induced DAF transcription was significantly attenuated in Trif-deficient mice. Likewise, IR-induced intestinal damage, complement component 3 deposition and prostaglandin E(2) production were attenuated in Helicobacter-infected, Trif-deficient but not MyD88(-/-) mice. While infection attenuated IR-induced cytokine production in wild-type and MyD88(-/-) mice, there was no further decrease in Trif-deficient mice. These data indicate distinct roles for MyD88 and Trif in IR-induced inflammation and suggest that chronic, undetected infections, such as Helicobacter, alter the use of the adaptor proteins to induce damage.
- Published
- 2011
- Full Text
- View/download PDF
42. Macrophage-produced IL-12p70 mediates hemorrhage-induced damage in a complement-dependent manner.
- Author
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Hylton DJ, Hoffman SM, Van Rooijen N, Tomlinson S, and Fleming SD
- Subjects
- Animals, Bone Density Conservation Agents pharmacology, Clodronic Acid pharmacology, Complement Activation drug effects, Complement Activation genetics, Complement Activation immunology, Complement Inactivating Agents pharmacology, Complement System Proteins genetics, Complement System Proteins immunology, Immunity, Innate drug effects, Immunity, Innate genetics, Immunity, Innate immunology, Interleukin-12 genetics, Interleukin-12 immunology, Intestinal Diseases etiology, Intestinal Diseases genetics, Intestinal Diseases immunology, Intestines immunology, Leukotriene B4 biosynthesis, Leukotriene B4 genetics, Leukotriene B4 immunology, Macrophage Activation drug effects, Macrophage Activation genetics, Macrophage Activation immunology, Macrophages immunology, Macrophages pathology, Mice, Mice, Knockout, Neutrophil Infiltration drug effects, Neutrophil Infiltration genetics, Neutrophil Infiltration immunology, Neutrophils immunology, Neutrophils metabolism, Shock, Hemorrhagic complications, Shock, Hemorrhagic drug therapy, Shock, Hemorrhagic genetics, Shock, Hemorrhagic immunology, Time Factors, Tumor Necrosis Factor-alpha biosynthesis, Tumor Necrosis Factor-alpha genetics, Tumor Necrosis Factor-alpha immunology, Complement System Proteins metabolism, Interleukin-12 biosynthesis, Intestinal Diseases metabolism, Intestinal Mucosa metabolism, Macrophages metabolism, Shock, Hemorrhagic metabolism
- Abstract
Hemorrhage and hemorrhagic shock instigate intestinal damage and inflammation. Multiple components of the innate immune response, including complement and neutrophil infiltration, are implicated in this pathology. To investigate the interaction of complement activation and other components of the innate immune response during hemorrhage, we treated mice after hemorrhage with CR2-fH, a targeted inhibitor of the alternative complement pathway and assessed intestinal damage and inflammation 2 h after hemorrhage. In wild-type mice, CR2-fH attenuated hemorrhage-induced, midjejunal damage and inflammation as determined by decreased mucosal damage, macrophage infiltration, leukotriene B4, IL-12p40, and TNF-[alpha] production. The critical nature of intestinal macrophage infiltration and activation in the response to hemorrhage was further determined using mice pretreated with clodronate-containing liposomes. The absence of either macrophages or IL-12p70 attenuated intestinal damage. These data suggest that complement activation and macrophage infiltration with IL-12p70 production are critical to hemorrhage-induced midjejunal damage and inflammation.
- Published
- 2011
- Full Text
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43. CR2+ marginal zone B cell production of pathogenic natural antibodies is C3 independent.
- Author
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Woods KM, Pope MR, Hoffman SM, and Fleming SD
- Subjects
- Adoptive Transfer, Animals, Autoantibodies therapeutic use, B-Lymphocyte Subsets pathology, B-Lymphocyte Subsets transplantation, Cells, Cultured, Complement C3 deficiency, Homeodomain Proteins genetics, Immunophenotyping, Intestinal Mucosa blood supply, Intestinal Mucosa immunology, Intestinal Mucosa pathology, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptors, Complement 3d biosynthesis, Receptors, Complement 3d deficiency, Reperfusion Injury immunology, Reperfusion Injury pathology, Reperfusion Injury therapy, Spleen metabolism, Spleen pathology, Autoantibodies biosynthesis, B-Lymphocyte Subsets immunology, Complement C3 physiology, Receptors, Complement 3d physiology, Spleen immunology
- Abstract
Intestinal ischemia-reperfusion (IR)-induced damage requires complement receptor 2 (CR2) for generation of the appropriate natural Ab repertoire. Pathogenic Abs recognize neoantigens on the ischemic tissue, activate complement, and induce intestinal damage. Because C3 cleavage products act as ligands for CR2, we hypothesized that CR2(hi) marginal zone B cells (MZBs) require C3 for generation of the pathogenic Abs. To explore the ability of splenic CR2(+) B cells to generate the damaging Ab repertoire, we adoptively transferred either MZBs or follicular B cells (FOBs) from C57BL/6 or Cr2(-/-) mice into Rag-1(-/-) mice. Adoptive transfer of wild type CR2(hi) MZBs but not CR2(lo) FOBs induced significant damage, C3 deposition, and inflammation in response to IR. In contrast, similarly treated Rag-1(-/-) mice reconstituted with either Cr2(-/-) MZB/B1 B cells (B1Bs) or FOBs lacked significant intestinal damage and displayed limited complement activation. To determine whether C3 cleavage products are critical in CR2-dependent Ab production, we evaluated the ability of the natural Ab repertoire of C3(-/-) mice to induce damage in response to IR. Infusion of C3(-/-) serum into Cr2(-/-) mice restored IR-induced tissue damage. Furthermore, Rag-1(-/-) mice sustained significant damage after infusion of Abs from C3(-/-) but not Cr2(-/-) mice. Finally, adoptive transfer of MZBs from C3(-/-) mice into Rag-1(-/-) mice resulted in significant tissue damage and inflammation. These data indicate that CR2 expression on MZBs is sufficient to induce the appropriate Abs required for IR-induced tissue damage and that C3 is not critical for generation of the pathogenic Abs.
- Published
- 2011
- Full Text
- View/download PDF
44. Natural Helicobacter infection modulates mouse intestinal muscularis macrophage responses.
- Author
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Hoffman SM and Fleming SD
- Subjects
- Animals, Antigens, Surface metabolism, Chemokines biosynthesis, Helicobacter hepaticus, In Vitro Techniques, Intestinal Mucosa metabolism, Macrophages metabolism, Mice, Mice, Inbred C57BL, Muscle, Smooth metabolism, Phagocytosis, Cytokines biosynthesis, Helicobacter Infections immunology, Intestines immunology, Macrophages immunology, Muscle, Smooth immunology
- Abstract
Helicobacter species are common laboratory pathogens which induce intestinal inflammation and disease in susceptible mice. Since in vitro studies indicate that Helicobacter products activate macrophages, we hypothesized that in vivo Helicobacter infection regulates the inflammatory response of intestinal muscularis macrophages from C57Bl/6 mice. Helicobacter hepaticus infection increased surface expression of macrophage markers F4/80, CD11b and MHC-II within whole intestinal muscle mounts. However, constitutive cytokine and chemokine production by macrophages isolated from infected mice significantly decreased compared to macrophages from uninfected mice despite no detectable bacterial products in the cultures. In addition, muscularis macrophages from infected mice up-regulated FIZZ-1 and SK-1 gene expression, suggesting the macrophages had an anti-inflammatory phenotype. Corresponding with increased anti-inflammatory gene expression, macrophages from infected mice were more phagocytic but did not produce cytokines after stimulation with LPS and IFN-γ or immune complexes and IL-4. Therefore, the presence of Helicobacter infection matures intestinal muscularis macrophages, modulating the constitutive macrophage response to become more anti-inflammatory and resistant to secondary stimulation., (Copyright © 2010 John Wiley & Sons, Ltd.)
- Published
- 2010
- Full Text
- View/download PDF
45. Domain V peptides inhibit beta2-glycoprotein I-mediated mesenteric ischemia/reperfusion-induced tissue damage and inflammation.
- Author
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Fleming SD, Pope MR, Hoffman SM, Moses T, Bukovnik U, Tomich JM, Wagner LM, and Woods KM
- Subjects
- Animals, Immunohistochemistry, Immunoprecipitation, Inflammation immunology, Intestinal Mucosa metabolism, Mesentery pathology, Mice, Mice, Inbred C57BL, Mice, Knockout, Reperfusion Injury pathology, Inflammation metabolism, Mesentery metabolism, Reperfusion Injury metabolism, beta 2-Glycoprotein I metabolism
- Abstract
Reperfusion of ischemic tissue induces significant tissue damage in multiple conditions, including myocardial infarctions, stroke, and transplantation. Although not as common, the mortality rate of mesenteric ischemia/reperfusion (IR) remains >70%. Although complement and naturally occurring Abs are known to mediate significant damage during IR, the target Ags are intracellular molecules. We investigated the role of the serum protein, β2-glycoprotein I as an initiating Ag for Ab recognition and β2-glycoprotein I (β2-GPI) peptides as a therapeutic for mesenteric IR. The time course of β2-GPI binding to the tissue indicated binding and complement activation within 15 min postreperfusion. Treatment of wild-type mice with peptides corresponding to the lipid binding domain V of β2-GPI blocked intestinal injury and inflammation, including cellular influx and cytokine and eicosanoid production. The optimal therapeutic peptide (peptide 296) contained the lysine-rich region of domain V. In addition, damage and most inflammation were also blocked by peptide 305, which overlaps with peptide 296 but does not contain the lysine-rich, phospholipid-binding region. Importantly, peptide 296 retained efficacy after replacement of cysteine residues with serine. In addition, infusion of wild-type serum containing reduced levels of anti-β2-GPI Abs into Rag-1(-/-) mice prevented IR-induced intestinal damage and inflammation. Taken together, these data suggest that the serum protein β2-GPI initiates the IR-induced intestinal damage and inflammatory response and as such is a critical therapeutic target for IR-induced damage and inflammation.
- Published
- 2010
- Full Text
- View/download PDF
46. Hemorrhage-induced intestinal damage is complement-independent in Helicobacter hepaticus-infected mice.
- Author
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Hylton DJ, Phillips LM, Hoffman SM, and Fleming SD
- Subjects
- Animals, Chemokines metabolism, Chemotactic Factors metabolism, Chronic Disease, Complement C5a biosynthesis, Gastroenteritis immunology, Gastroenteritis microbiology, Gastrointestinal Hemorrhage etiology, Leukotriene B4 metabolism, Macrophages pathology, Male, Mice, Mice, Inbred C57BL, Neutrophils pathology, Nitric Oxide biosynthesis, Nitric Oxide physiology, Specific Pathogen-Free Organisms, Tumor Necrosis Factor-alpha physiology, Gastroenteritis pathology, Gastrointestinal Hemorrhage immunology, Helicobacter Infections immunology, Jejunum pathology
- Abstract
With more than half of the world population infected, Helicobacter infection is an important public health issue associated with gastrointestinal cancers and inflammatory bowel disease. Animal studies indicate that complement and oxidative stress play a role in Helicobacter infections. Hemorrhage (HS) induces tissue damage that is attenuated by blockade of either complement activation or oxidative stress products. Therefore, we hypothesized that chronic Helicobacter hepaticus infection would modulate HS-induced intestinal damage and inflammation. To test this hypothesis, we examined HS-induced jejunal damage and inflammation in uninfected and H. hepaticus-infected mice. Helicobacter hepaticus infection increased HS-induced midjejunal mucosal damage despite attenuating complement activation. In addition, infection alone increased chemokine secretion, changing the HS-induced neutrophil infiltration to a macrophage-mediated inflammatory response. The HS-induced macrophage infiltration correlated with increased secretion of tumor necrosis factor-α and nitric oxide in the infected mice. Together, these data indicate that Helicobacter infection modulates the mechanism of HS-induced intestinal damage and inflammation from a complement-mediated response to a macrophage response with elevated tumor necrosis factor-α and nitric oxide. These data indicate that chronic low-level infections change the response to trauma and should be considered when designing and administering therapeutics.
- Published
- 2010
- Full Text
- View/download PDF
47. Gelatinase contributes to the pathogenesis of endocarditis caused by Enterococcus faecalis.
- Author
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Thurlow LR, Thomas VC, Narayanan S, Olson S, Fleming SD, and Hancock LE
- Subjects
- Animals, Aortic Valve microbiology, Aortic Valve pathology, Bacterial Proteins genetics, Bacterial Proteins metabolism, Complement C5a metabolism, Endocarditis, Bacterial microbiology, Enterococcus faecalis enzymology, Enterococcus faecalis genetics, Gelatinases genetics, Gram-Positive Bacterial Infections microbiology, HL-60 Cells, Humans, Mutation, Peptide Hydrolases genetics, Peptide Hydrolases metabolism, Rabbits, Endocarditis, Bacterial pathology, Enterococcus faecalis pathogenicity, Gelatinases metabolism, Gram-Positive Bacterial Infections pathology
- Abstract
The Gram-positive pathogen Enterococcus faecalis is a leading agent of nosocomial infections, including urinary tract infections, surgical site infections, and bacteremia. Among the infections caused by E. faecalis, endocarditis remains a serious clinical manifestation and unique in that it is commonly acquired in a community setting. Infective endocarditis is a complex disease, with many host and microbial components contributing to the formation of bacterial biofilm-like vegetations on the aortic valve and adjacent areas within the heart. In the current study, we compared the pathogenic potential of the vancomycin-resistant E. faecalis V583 and three isogenic protease mutants (ΔgelE, ΔsprE, and ΔgelE ΔsprE mutants) in a rabbit model of enterococcal endocarditis. The bacterial burdens displayed by GelE(-) mutants (ΔgelE and ΔgelE ΔsprE mutants) in the heart were significantly lower than those of V583 or the SprE(-) mutant. Vegetations on the aortic valve infected with GelE(-) mutants (ΔgelE and ΔgelE ΔsprE mutants) also showed a significant increase in deposition of fibrinous matrix layer and increased chemotaxis of inflammatory cells. In support of a role for proteolytic modulation of the immune response to E. faecalis, we also demonstrate that GelE can cleave the anaphylatoxin complement C5a and that this proteolysis leads to decreased neutrophil migration in vitro. In vivo, a decreased heterophil (neutrophil-like cell) migration was observed at tissue sites infected with GelE-producing strains but not at those infected with SprE-producing strains. Taken together, these observations suggest that of the two enterococcal proteases, gelatinase is the principal mediator of pathogenesis in endocarditis.
- Published
- 2010
- Full Text
- View/download PDF
48. Complement regulates TLR4-mediated inflammatory responses during intestinal ischemia reperfusion.
- Author
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Pope MR, Hoffman SM, Tomlinson S, and Fleming SD
- Subjects
- Animals, Enzyme-Linked Immunosorbent Assay, Inflammation metabolism, Intestinal Mucosa metabolism, Intestines injuries, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Reperfusion Injury metabolism, Reverse Transcriptase Polymerase Chain Reaction, Toll-Like Receptor 4 metabolism, Complement Activation immunology, Inflammation immunology, Intestines immunology, Reperfusion Injury immunology, Toll-Like Receptor 4 immunology
- Abstract
Innate immune responses including TLR4 and complement activation are required for mesenteric ischemia/reperfusion (IR)-induced tissue damage. We examined the regulation of TLR4 and complement activation in a mouse model of intestinal IR. Intestinal IR-induced C3 deposition in a TLR4 dependent manner. In addition, in wild-type but not TLR4 deficient mice, IR significantly increased C3 and Factor B (FB) mRNA expression within the intestine. To further examine the role of TLR4 and complement, we administered the complement inhibitor, CR2-Crry, to target local complement activation in wild-type C57Bl/10, and TLR4 deficient B10/ScN mice. TLR4 deficient mice sustained less damage and inflammation after IR than wild-type mice, but administration of CR2-Crry did not further reduce tissue damage. In contrast, CR2-Crry treatment of wild-type mice was accompanied by a reduction in complement activation and in C3 and FB transcription in response to IR. CR2-Crry also significantly decreased intestinal IL-6 and IL-12p40 production in both the wild-type and TLR4 deficient mice. These data indicate that TLR4 regulates extrahepatic complement production while complement regulates TLR4-mediated cytokine production during intestinal IR., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
49. Intestinal lipid alterations occur prior to antibody-induced prostaglandin E2 production in a mouse model of ischemia/reperfusion.
- Author
-
Sparkes BL, Slone EE, Roth M, Welti R, and Fleming SD
- Subjects
- Animals, Cyclooxygenase 2 genetics, Cyclooxygenase 2 metabolism, Intestinal Mucosa immunology, Intestinal Mucosa pathology, Ischemia immunology, Ischemia pathology, Jejunum injuries, Jejunum metabolism, Lysophosphatidylcholines metabolism, Lysophospholipids metabolism, Mice, Mice, Inbred C57BL, Mice, Knockout, Phospholipids immunology, RNA, Messenger genetics, RNA, Messenger metabolism, Reperfusion Injury immunology, Reperfusion Injury pathology, Reverse Transcriptase Polymerase Chain Reaction, Spectrometry, Mass, Electrospray Ionization, Sphingomyelins metabolism, Antibodies, Monoclonal pharmacology, Dinoprostone metabolism, Homeodomain Proteins physiology, Intestinal Mucosa metabolism, Ischemia metabolism, Phospholipids metabolism, Reperfusion Injury metabolism
- Abstract
Ischemia/reperfusion (IR) induced injury results in significant tissue damage in wild-type, but not antibody-deficient, Rag-1(-/-) mice. However, Rag-1(-/-) mice sustain intestinal damage after administration of wild-type antibodies or naturally occurring, specific anti-phospholipid related monoclonal antibodies, suggesting involvement of a lipid antigen. We hypothesized that IR initiates metabolism of cellular lipids, resulting in production of an antigen recognized by anti-phospholipid antibodies. At multiple time points after Sham or IR treatment, lipids extracted from mouse jejunal sections were analyzed by electrospray ionization triple quadrupole mass spectrometry. Within 15min of reperfusion, IR induced significantly more lysophosphatidylcholine (lysoPC), lysophosphatidylglycerol (lysoPG) and free arachidonic acid (AA) production than Sham treatment. While lysoPC, lysoPG, and free AA levels were similar in C57Bl/6 (wild-type) and Rag-1(-/-) mice, IR led to Cox-2 activation and prostaglandin E(2) (PGE(2)) production in wild-type, but not in the antibody-deficient, Rag-1(-/-) mice. Administration of wild-type antibodies to Rag-1(-/-) mice restored PGE(2) production and intestinal damage. These data indicate that IR-induced intestinal damage requires antibodies for Cox-2 stimulated PGE(2) production but not for production of lysoPC and free AA., (2010 Elsevier B.V. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
50. The effect of repeated freezing and thawing on human sperm DNA fragmentation.
- Author
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Thomson LK, Fleming SD, Barone K, Zieschang JA, and Clark AM
- Subjects
- Adult, Centrifugation, Density Gradient methods, Centrifugation, Density Gradient standards, Cryopreservation standards, Cryoprotective Agents pharmacology, Humans, Infertility, Male physiopathology, Infertility, Male therapy, Male, Middle Aged, Prospective Studies, Semen Preservation adverse effects, Semen Preservation standards, Spermatozoa drug effects, Cryopreservation methods, DNA Fragmentation drug effects, Freezing, Semen Preservation methods, Spermatozoa physiology
- Abstract
Objective: To investigate the effects of repeated freezing and thawing on human sperm motility, vitality, and DNA integrity., Design: A prospective clinical study., Setting: Tertiary care fertility clinic., Patient(s): Twenty men presenting for infertility investigations., Intervention(s): Each sample was subjected to three cycles of freezing and thawing both with and without washing steps and the addition of fresh cryoprotectant between each cycle., Main Outcome Measure(s): Percentage sperm DNA fragmentation, motility, and vitality before and following repeated freezing and thawing., Result(s): The percentage sperm DNA fragmentation rose significantly following each freeze-thaw cycle; however, samples that were not washed and to which fresh cryoprotectant was not added after each cycle fared significantly better than their washed counterparts. Both motility and vitality decreased steadily following each cycle but cell survival was significantly greater in the unwashed samples., Conclusion(s): In terms of the level of sperm DNA fragmentation, up to three cycles of freezing and thawing can be performed with a level of risk comparable to that following a single cycle of freezing and thawing. This is provided that samples are refrozen in their original cryoprotectant and not washed or altered in any way in between, and provided that they are separated by density gradient centrifugation or swim-up before use in assisted reproduction technology., (Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
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