43 results on '"Schuurs TA"'
Search Results
2. Local renal upregulation of complement C3 and fibrinogen as part of the acute phase response in brain-dead donors
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Damman, J, Seelen, MA, Nijboer, WN, Ploeg, RJ, and Schuurs, TA
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- 2016
3. Metabolic changes in kidneys from brain-dead donors: Phosphoenolpyruvate carboxykinase expression predicts early graft function
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Schuurs, TA, De Roos, B, Rucklidge, G, Zwaagstra, JJ, and Ploeg, RJ
- Published
- 2016
4. Macrophage overgrowth affects neighboring nonovergrown encapsulated islets
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de Groot, M, Schuurs, TA, Leuvenink, HGD, van Schilfgaarde, R, and Groningen Institute for Organ Transplantation (GIOT)
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endocrine system ,replication ,pancreatic islets ,endocrine system diseases ,CYTOKINES ,apoptosis ,DEATH ,INHIBITION ,IN-VITRO ,MICROCAPSULES ,macrophages ,necrosis ,ALGINATE ,nitric oxide ,NITRIC-OXIDE TOXICITY ,PANCREATIC BETA-CELLS ,rat ,PROTECTION - Abstract
Background. Encapsulation significantly prolongs islet graft survival in the absence of immunosuppression. However, encapsulated islet graft survival is limited to periods of several months. Part of the encapsulated islet graft is affected by a nonprogressive pericapsular overgrowth. To investigate whether macrophages on overgrown capsules affect neighboring nonovergrown encapsulated islets, encapsulated islets were studied during coculture. Materials and methods. Encapsulated islet function, islet vitality, and islet cell replication were assessed, as well as the mRNA expression of Bcl-2, Bax, inducible nitric oxide synthase, and monocyte chemoattractant protein-1 in encapsulated islets after 48 h of culture together with microcapsules with macrophage overgrowth. Overgrown capsules were retrieved from the rat peritoneum, three weeks after implantation of an encapsulated islet graft. Results. Coculture was associated with inhibition of the stimulated insulin secretion, with decreased cell replication, and with increased cell necrosis, but not with apoptosis of encapsulated islet cells. mRNA expression levels in encapsulated islets after coculture were not different from controls, except for a decrease in Bax mRNA. We found a high level of nitrite, as an indicator of nitric oxide production, but not an increase in inducible nitric oxide synthase mRNA in islets. This, in combination with the absence of increase in monocyte chemoattractant protein-1 mRNA and the lack of apoptosis, indicates that neither interleukin-1beta, nor tumor necrosis factor-alpha was responsible for the deleterious effects of coculture on encapsulated islets. Conclusions. Nonovergrown encapsulated islets are affected by the overgrowth on encapsulated islets in their close proximity. This overgrowth contains macrophages that produce nitric oxide which, rather than cytokines, may be held responsible for the deleterious effect on the neighboring encapsulated islets. (C) 2003 Elsevier Inc. All rights reserved.
- Published
- 2003
5. Reactive arthritis: does screening stools by polymerase chain reaction for Shiga toxin-producingEscherichia coli(STEC) make sense?
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Houtman, PM, primary, Spoorenberg, A, additional, Schuurs, TA, additional, and Mooi-Kokenberg, EANM, additional
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- 2012
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6. The isolation of 2 tandemly linked glyceraldehyde-3-phosphate dehydrogenase genes from agaricus bisporus
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Harmsen, MC, Scheer, J, Schuurs, TA, Wessels, JGH, and VANGRIENSVEN, LJL
- Published
- 1991
7. Reactive arthritis: does screening stools by polymerase chain reaction for Shiga toxin-producing Escherichia coli (STEC) make sense?
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Houtman, PM, Spoorenberg, A, Schuurs, TA, and Mooi-Kokenberg, EANM
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CASE studies ,INFECTIOUS arthritis ,ARTHRITIS patients ,ESCHERICHIA coli ,POLYMERASE chain reaction - Abstract
The article presents several case studies of reactive arthritis (ReA) patients from the Netherlands. It is mentioned that, patients were screened for Shiga toxin-producing Escherichia coli (STEC), by polymerase chain reaction (PCR). As mentioned, extra-articular involvement in STEC-related ReA may include erythema nodosum, rash, conjunctivitis, and genitourinary tract symptoms, such as dysuria and balanitis.
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- 2012
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8. Cutaneous Brucellosis unmasked as Aureimonas altamirensis in a wound culture.
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Roo-Brand G, Schuurs TA, and van Zeijl JH
- Abstract
Aureimonas altamirensis was isolated from a wound culture and initially misidentified as Brucella melitensis by the VITEK® 2 system. The VITEK-MS did not provide identification whereas the Bruker MALDI-ToF MS system and 16-S sequencing revealed a clear identification, which highlights the importance of inclusion of species in databases for accurate and fast identification of bacteria., Competing Interests: None., (© 2022 The Authors.)
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- 2022
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9. From a case-control survey to a diagnostic viral gastroenteritis panel for testing of general practitioners' patients.
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Bruijnesteijn van Coppenraet LES, Flipse J, Wallinga JA, Vermeer M, van der Reijden WA, Weel JFL, van der Zanden AGM, Schuurs TA, and Ruijs GJHM
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- Adenoviridae genetics, Adenoviridae isolation & purification, Adenoviridae pathogenicity, Bocavirus genetics, Bocavirus isolation & purification, Bocavirus pathogenicity, Child, Preschool, Enterovirus Infections genetics, Enterovirus Infections pathology, Enterovirus Infections virology, Female, Gastroenteritis genetics, Gastroenteritis pathology, Gastroenteritis virology, General Practitioners, Humans, Infant, Male, Norovirus genetics, Norovirus isolation & purification, Norovirus pathogenicity, Patients, Rotavirus genetics, Rotavirus isolation & purification, Rotavirus pathogenicity, Sapovirus genetics, Sapovirus isolation & purification, Sapovirus pathogenicity, Enterovirus Infections diagnosis, Feces virology, Gastroenteritis diagnosis
- Abstract
Objective: To evaluate the pathogenicity of a broad range of 11 possible gastroenteritis viruses, by means of statistical relationships with cases vs. controls, or Ct-values, in order to establish the most appropriate diagnostic panel for our general practitioner (GP) patients in the Netherlands (2010-2012)., Methods: Archived stool samples from 1340 cases and 1100 controls were retested using internally controlled multiplex real-time PCRs for putative pathogenic gastroenteritis viruses: adenovirus, astrovirus, bocavirus, enterovirus, norovirus GI and GII, human parechovirus, rotavirus, salivirus, sapovirus, and torovirus., Results: The prevalence of any virus in symptomatic cases and asymptomatic controls was 16.6% (223/1340) and 10.2% (112/1100), respectively. Prevalence of astrovirus (adjusted odds ratio (aOR) 10.37; 95% confidence interval (CI) 1.34-80.06) and norovirus GII (aOR 3.10; CI 1.62-5.92) was significantly higher in cases versus controls. Rotavirus was encountered only in cases. We did not find torovirus and there was no statistically significant relationship with cases for salivirus (aOR 1,67; (CI) 0.43-6.54)), adenovirus non-group F (aOR 1.20; CI 0.75-1.91), bocavirus (aOR 0.85; CI 0.05-13.64), enterovirus (aOR 0.83; CI 0.50-1.37), human parechovirus (aOR 1.61; CI 0.54-4.77) and sapovirus (aOR 1.15; CI 0.67-1.98). Though adenovirus group F (aOR 6.37; CI 0.80-50.92) and norovirus GI (aOR 2.22, CI: 0.79-6.23) are known enteropathogenic viruses and were more prevalent in cases than in controls, this did not reach significance in this study. The Ct value did not discriminate between carriage and disease in PCR-positive subjects., Conclusions: In our population, diagnostic gastroenteritis tests should screen for adenovirus group F, astrovirus, noroviruses GI and GII, and rotavirus. Case-control studies as ours are lacking and should also be carried out in populations from other epidemiological backgrounds., Competing Interests: The authors have declared that no competing interests exist.
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- 2021
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10. Distribution and relevance of Dientamoeba fragilis and Blastocystis species in gastroenteritis: results from a case-control study.
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de Boer MD, Schuurs TA, Vermeer M, Ruijs GJHM, van der Zanden AGM, Weel JF, and Bruijnesteijn van Coppenraet LES
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- Adolescent, Adult, Case-Control Studies, Child, Child, Preschool, Diarrhea parasitology, Feces parasitology, Female, Gastroenteritis epidemiology, Humans, Male, Middle Aged, Netherlands epidemiology, Prevalence, Young Adult, Blastocystis isolation & purification, Blastocystis Infections epidemiology, Dientamoeba isolation & purification, Dientamoebiasis epidemiology, Gastroenteritis parasitology
- Abstract
The actual role of Dientamoeba fragilis and Blastocystis in patients with gastrointestinal symptoms is still under debate. A multicenter case-control study was performed in The Netherlands to elucidate the clinical relevance of molecular diagnostics results in gastroenteritis (GE). Samples from this case-control study were used to perform a detailed analysis on the presence of D. fragilis and Blastocystis in relation to gastrointestinal symptoms. In the present study, a real-time PCR for Blastocystis was performed on 1374 case samples and 1026 control samples from the multicenter gastroenteritis case-control study previously tested for D. fragilis. Prevalence of both micro-organisms was highest in children under 20 years of age and lowest in the oldest age group. A significantly lower overall detection of D. fragilis and Blastocystis was found in cases (both 25.8%) as compared to controls (37.6% and 40.0%, respectively). The difference for D. fragilis was statistically significant for subjects above 20 years of age. For Blastocystis, the difference was statistically significant in all age groups, except in children less than 5 years of age. A negative relation between D. fragilis-positive cases and diarrhea was found in this study population. More GE symptoms were reported in cases without D. fragilis or Blastocystis. In the present study, prevalence of both D. fragilis and Blastocystis is lower in cases with gastroenteritic symptoms than in controls. Besides, in cases with D. fragilis or Blastocystis, no association is shown between any of the GE symptoms. Interestingly, this suggests that the presence of these protozoans may be considered characteristic of a healthy intestinal microbiome.
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- 2020
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11. Harmonization of PCR-based detection of intestinal pathogens: experiences from the Dutch external quality assessment scheme on molecular diagnosis of protozoa in stool samples.
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Schuurs TA, Koelewijn R, Brienen EAT, Kortbeek T, Mank TG, Mulder B, Stelma FF, van Lieshout L, and van Hellemond JJ
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- Animals, Cryptosporidium genetics, Cryptosporidium isolation & purification, DNA, Protozoan genetics, DNA, Protozoan standards, Entamoeba histolytica genetics, Entamoeba histolytica isolation & purification, Gastrointestinal Tract parasitology, Giardia lamblia genetics, Giardia lamblia isolation & purification, Humans, Laboratories, Hospital standards, Netherlands, Parasites isolation & purification, Parasitic Diseases diagnosis, Polymerase Chain Reaction standards, Quality Control, Sensitivity and Specificity, DNA, Protozoan metabolism, Feces parasitology, Parasites genetics, Polymerase Chain Reaction methods
- Published
- 2018
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12. Epidemiology of Extended-Spectrum β-Lactamase-Producing E. coli and Vancomycin-Resistant Enterococci in the Northern Dutch-German Cross-Border Region.
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Zhou X, García-Cobos S, Ruijs GJHM, Kampinga GA, Arends JP, Borst DM, Möller LV, Holman ND, Schuurs TA, Bruijnesteijn van Coppenraet LE, Weel JF, van Zeijl JH, Köck R, Rossen JWA, and Friedrich AW
- Abstract
Objectives: To reveal the prevalence and epidemiology of extended-spectrum β-lactamase (ESBL)- and/or plasmid AmpC (pAmpC)- and carbapenemase (CP) producing Enterobacteriaceae and vancomycin-resistant enterococci (VRE) across the Northern Dutch-German border region. Methods: A point-prevalence study on ESBL/pAmpC/CP producing Enterobacteriaceae and VRE was carried out in hospitalized patients in the Northern Netherlands ( n = 445, 2012-2013) and Germany ( n = 242, 2012). Healthy individuals from the Dutch community ( n = 400, 2010-2012) were also screened. In addition, a genome-wide gene-by-gene approach was applied to study the epidemiology of ESBL- Escherichia coli and VRE. Results: A total of 34 isolates from 27 patients (6.1%) admitted to Dutch hospitals were ESBL/pAmpC positive and 29 ESBL- E. coli , three pAmpC- E. coli , one ESBL- Enterobacter cloacae , and one pAmpC- Proteus mirabilis were found. In the German hospital, 18 isolates (16 E. coli and 2 Klebsiella pneumoniae ) from 17 patients (7.7%) were ESBL positive. In isolates from the hospitalized patients CTX-M-15 was the most frequently detected ESBL-gene. In the Dutch community, 11 individuals (2.75%) were ESBL/pAmpC positive: 10 ESBL - E. coli (CTX-M-1 being the most prevalent gene) and one pAmpC E. coli . Six Dutch (1.3%) and four German (3.9%) hospitalized patients were colonized with VRE. Genetic relatedness by core genome multi-locus sequence typing (cgMLST) was found between two ESBL- E. coli isolates from Dutch and German cross-border hospitals and between VRE isolates from different hospitals within the same region. Conclusion: The prevalence of ESBL/pAmpC- Enterobacteriaceae was similar in hospitalized patients across the Dutch-German border region, whereas VRE prevalence was slightly higher on the German side. The overall prevalence of the studied pathogens was lower in the community than in hospitals in the Northern Netherlands. Cross-border transmission of ESBL- E. coli and VRE seems unlikely based on cgMLST analysis, however continuous monitoring is necessary to control their spread and stay informed about their epidemiology.
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- 2017
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13. Dynamics of nasopharyngeal pneumococcal carriage during the course of viral bronchiolitis.
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Faber TE, Schuurs TA, Veeger NJ, Hennus MP, and Bont LJ
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- Bacterial Load, Bronchiolitis, Viral complications, Coinfection, Female, Hospitalization, Humans, Infant, Male, Pneumococcal Infections complications, Prospective Studies, Bronchiolitis, Viral microbiology, Carrier State microbiology, Nasopharynx microbiology, Pneumococcal Infections microbiology, Streptococcus pneumoniae isolation & purification
- Abstract
The effect of viral infection on nasopharyngeal carriage of Streptococcus pneumoniae during childhood is not well known. We studied dynamics of pneumococcal colonization by quantitative PCR during the natural course of viral bronchiolitis. At time of admission, 47 (47%) of 100 patients with bronchiolitis carried pneumococci. In patients with viral bronchiolitis who did not receive antibiotics, pneumococcal load decreased from time of admission to discharge (n = 35, cycle threshold 23 vs. 25, P = 0.0017) and from discharge to follow-up (n = 22, cycle threshold 25 vs. 40, P = 0.003). We conclude that viral respiratory infection is negatively associated with pneumococcal colonization of the upper airways. Pediatr Pulmonol. 2016;51:863-867. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)
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- 2016
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14. Case-control comparison of bacterial and protozoan microorganisms associated with gastroenteritis: application of molecular detection.
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Bruijnesteijn van Coppenraet LE, Dullaert-de Boer M, Ruijs GJ, van der Reijden WA, van der Zanden AG, Weel JF, and Schuurs TA
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- Adolescent, Adult, Aged, Aged, 80 and over, Animals, Bacteria classification, Bacteria isolation & purification, Bacterial Infections epidemiology, Case-Control Studies, Child, Child, Preschool, Female, Gastroenteritis epidemiology, Humans, Infant, Infant, Newborn, Male, Middle Aged, Multiplex Polymerase Chain Reaction, Netherlands epidemiology, Parasites classification, Parasites isolation & purification, Protozoan Infections epidemiology, Real-Time Polymerase Chain Reaction, Young Adult, Bacterial Infections microbiology, Feces microbiology, Feces parasitology, Gastroenteritis microbiology, Gastroenteritis parasitology, Molecular Diagnostic Techniques, Protozoan Infections parasitology
- Abstract
The introduction of molecular detection of infectious organisms has led to increased numbers of positive findings, as observed for pathogens causing gastroenteritis (GE). However, because little is known about the prevalence of these pathogens in the healthy asymptomatic population, the clinical value of these additional findings is unclear. A case-control study was carried out in a population of patients served by general practitioners in the Netherlands. A total of 2710 fecal samples from case and matched control subjects were subjected to multiplex real-time PCR for the 11 most common bacterial and four protozoal causes of GE. Of 1515 case samples, 818 (54%) were positive for one or more target organisms. A total of 49% of the controls were positive. Higher positivity rates in cases compared to controls were observed for Campylobacter spp., Salmonella spp., Clostridium difficile, enteroinvasive Escherichia coli/Shigella spp., enterotoxigenic E. coli, enteroaggregative E. coli, atypical enteropathogenic E. coli (EPEC), Cryptosporidium parvum/hominis, and Giardia lamblia. However, Dientamoeba fragilis and Shiga-like toxigenic E. coli were detected significantly less frequent in cases than in controls, while no difference in prevalence was found for typical EPEC and enterohemorrhagic E. coli. The association between the presence of microorganisms and GE was the weakest in children aged 0 to 5 years. Higher relative loads in cases further support causality. This was seen for Campylobacter spp., Salmonella spp., enterotoxigenic E. coli, and C. parvum/hominis, and for certain age categories of those infected with C. difficile, enteroaggregative E. coli, and atypical EPEC. For D. fragilis and Shiga-like toxigenic E. coli/enterohemorrhagic E. coli, pathogen loads were lower in cases. Application of molecular diagnostics in GE is rapid, sensitive and specific, but results should be interpreted with care, using clinical and additional background information., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2015
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15. Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in an STI population: performances of the Presto CT-NG assay, the Lightmix Kit 480 HT CT/NG and the COBAS Amplicor with urine specimens and urethral/cervicovaginal samples.
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Schuurs TA, Verweij SP, Weel JF, Ouburg S, and Morré SA
- Abstract
Objectives: This study assessed the performances of the Presto CT-NG assay, the Lightmix Kit 480 HT CT/NG and the COBAS Amplicor for Chlamydia trachomatis and Neisseria gonorrhoeae detection., Design: A cross-sectional study design., Setting: Izore, Centre for Diagnosing Infectious Diseases in Friesland, the Netherlands, tested samples sent from regional sexually transmitted infection (STI) outpatient clinics and regional hospitals from the province Friesland, the Netherlands., Participants: Samples were collected from 292 men and 835 women. These samples included 560 urine samples and 567 urethral/cervicovaginal samples., Primary and Secondary Outcome Measures: The primary outcome measure is C trachomatis infection. No secondary outcome measures are available., Results: The sensitivity, specificity, positive predicative value (PPV) and negative predictive value (NPV) for C trachomatis detection in urine samples using the Presto CT-NG assay were 100%, 99.8%, 98.1% and 100%, respectively; for the Lightmix Kit 480 HT CT/NG: 94.2%, 99.8%, 96.1% and 99.4%, respectively; for the COBAS Amplicor: 92.3%, 99.6%, 96% and 99.2%, respectively. The sensitivity, specificity, PPV and NPV for C trachomatis detection in urethral/cervicovaginal swabs using the Presto CT-NG assay and the COBAS Amplicor were 100%, 99.8%, 97.7% and 100%, respectively; for the Lightmix Kit 480 HT CT/NG: 100%, 99.6%, 97.7% and 100%, respectively. Calculations for N gonorrhoeae could not be made due to a low prevalence., Conclusions: All three assays had a high sensitivity, specificity, PPV and NPV for C trachomatis, with best performance for the Presto CT-NG assay.
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- 2013
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16. Brain death induces renal expression of heme oxygenase-1 and heat shock protein 70.
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van Dullemen LF, Bos EM, Schuurs TA, Kampinga HH, Ploeg RJ, van Goor H, and Leuvenink HG
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- Animals, Base Sequence, Blotting, Western, DNA Primers, Immunohistochemistry, Male, Rats, Rats, Inbred F344, Reverse Transcriptase Polymerase Chain Reaction, Brain Death, HSP70 Heat-Shock Proteins metabolism, Heme Oxygenase-1 metabolism
- Abstract
Background: Kidneys derived from brain dead donors have lower graft survival and higher graft-function loss compared to their living donor counterpart. Heat Shock Proteins (HSP) are a large family of stress proteins involved in maintaining cell homeostasis. We studied the role of stress-inducible genes Heme Oxygenase-1 (HO-1), HSP27, HSP40, and HSP70 in the kidney following a 4 hour period of brain death., Methods: Brain death was induced in rats (n=6) by inflating a balloon catheter in the epidural space. Kidneys were analysed for HSPs using RT-PCR, Western blotting, and immunohistochemistry., Results: RT-PCR data showed a significant increase in gene expression for HO-1 and HSP70 in kidneys of brain dead rats. Western blotting revealed a massive increase in HO-1 protein in brain dead rat kidneys. Immunohistochemistry confirmed these findings, showing extensive HO-1 protein expression in the renal cortical tubules of brain dead rats. HSP70 protein was predominantly increased in renal distal tubules of brain dead rats treated for hypotension., Conclusion: Renal stress caused by brain death induces expression of the cytoprotective genes HO-1 and HSP70, but not of HSP27 and HSP40. The upregulation of these cytoprotective genes indicate that renal damage occurs during brain death, and could be part of a protective or recuperative mechanism induced by brain death-associated stress.
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- 2013
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17. Local renal complement C3 induction by donor brain death is associated with reduced renal allograft function after transplantation.
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Damman J, Nijboer WN, Schuurs TA, Leuvenink HG, Morariu AM, Tullius SG, van Goor H, Ploeg RJ, and Seelen MA
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- Adult, Animals, Blotting, Western, Cold Ischemia, Complement Activation, Enzyme-Linked Immunosorbent Assay, Female, Glomerular Filtration Rate, Humans, Immunoenzyme Techniques, Interleukin-6 metabolism, Kidney Failure, Chronic metabolism, Kidney Function Tests, Kidney Tubules cytology, Kidney Tubules metabolism, Living Donors, Male, Middle Aged, Prognosis, RNA, Messenger genetics, Rats, Rats, Inbred F344, Receptors, Complement metabolism, Reverse Transcriptase Polymerase Chain Reaction, Risk Factors, Tissue and Organ Harvesting, Brain Death physiopathology, Complement C3 metabolism, Kidney Failure, Chronic etiology, Kidney Failure, Chronic pathology, Kidney Transplantation adverse effects
- Abstract
Background: Kidneys derived from brain-dead donors have inferior outcomes after transplantation compared to kidneys from living donors. Strikingly, early and profound serum levels of IL-6 in brain-dead donors are observed. IL-6 is the main regulator of the acute phase response (APR). The aim of this translational study was to investigate the expression of renal acute phase proteins (APPs) following brain death (BD) and to assess the association with renal allograft outcome after transplantation., Methods: BD was induced in rats by inflating a subdurally placed balloon catheter. Kidney biopsies were obtained from human living and brain-dead donors at donation, after cold preservation and reperfusion. In vitro, renal proximal tubular epithelial cells (HK-2 cells) were stimulated with IL-6., Results: Both in human and rat brain-dead donors, C3 and FBG expression was enhanced at donation compared to living donors and sham-operated animals. In human donors, no additional expression was found after cold ischaemia or reperfusion. C3 expression after reperfusion was independently associated with decreased short-term function after transplantation in grafts from brain-dead donors. In cultured HK-2 cells, C3 production was induced in the presence of IL-6., Conclusions: In conclusion, BD induces renal C3 and FBG expression. Moreover, C3 expression is associated with a worse allograft function early after transplantation. Therefore, targeting renal APPs in brain-dead donors, especially complement C3, may improve transplant outcome.
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- 2011
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18. Kidney injury molecule-1 is an early noninvasive indicator for donor brain death-induced injury prior to kidney transplantation.
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Nijboer WN, Schuurs TA, Damman J, van Goor H, Vaidya VS, van der Heide JJ, Leuvenink HG, Bonventre JV, and Ploeg RJ
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- Animals, Biomarkers metabolism, Biopsy, Disease Models, Animal, Female, Graft Survival physiology, Hepatitis A Virus Cellular Receptor 1, Humans, Kidney pathology, Kidney Tubules, Proximal metabolism, Kidney Tubules, Proximal pathology, Male, Middle Aged, Predictive Value of Tests, Rats, Rats, Inbred F344, Regression Analysis, Brain Death metabolism, Cell Adhesion Molecules metabolism, Kidney metabolism, Kidney Transplantation physiology, Membrane Glycoproteins metabolism, Receptors, Virus metabolism, Tissue and Organ Procurement
- Abstract
With more marginal deceased donors affecting graft viability, there is a need for specific parameters to assess kidney graft quality at the time of organ procurement in the deceased donor. Recently, kidney injury molecule-1 (Kim-1) was described as an early biomarker of renal proximal tubular damage. We assessed Kim-1 in a small animal brain death model as an early and noninvasive marker for donor-derived injury related to brain death and its sequelae, with subsequent confirmation in human donors. In rat kidney, real-time PCR revealed a 46-fold Kim-1 gene upregulation after 4 h of brain death. In situ hybridization showed proximal tubular Kim-1 localization, which was confirmed by immunohistochemistry. Also, Luminex assay showed a 6.6-fold Kim-1 rise in urine after 4 h of brain death. In human donors, 2.5-fold kidney injury molecule-1 (KIM-1) gene upregulation and 2-fold higher urine levels were found in donation after brain death (DBD) donors compared to living kidney donors. Multiple regression analysis showed that urinary KIM-1 at brain death diagnosis was a positive predictor of recipient serum creatinine, 14 days (p < 0.001) and 1 year (p < 0.05) after kidney transplantation. In conclusion, we think that Kim-1 is a promising novel marker for the early, organ specific and noninvasive detection of brain death-induced donor kidney damage.
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- 2009
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19. Reduction of proteinuria in adriamycin-induced nephropathy is associated with reduction of renal kidney injury molecule (Kim-1) over time.
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Kramer AB, van Timmeren MM, Schuurs TA, Vaidya VS, Bonventre JV, van Goor H, and Navis G
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- Animals, Antibiotics, Antineoplastic toxicity, Biomarkers metabolism, Biopsy, Cell Adhesion Molecules urine, Doxorubicin toxicity, Fibrosis, Immunohistochemistry, Kidney Tubules, Proximal pathology, Male, Proteinuria chemically induced, Proteinuria pathology, RNA, Messenger metabolism, Rats, Rats, Wistar, Renal Insufficiency, Chronic chemically induced, Renal Insufficiency, Chronic pathology, Reverse Transcriptase Polymerase Chain Reaction, Cell Adhesion Molecules genetics, Cell Adhesion Molecules metabolism, Kidney Tubules, Proximal physiology, Proteinuria physiopathology, Renal Insufficiency, Chronic physiopathology
- Abstract
Tubulointerstitial lesions are important in the progression of proteinuric renal disease. Tubular kidney injury molecule-1 (Kim-1) is induced in acute renal injury and reversible as a natural course. Kim-1 is also present in chronic renal damage; however, the dynamics of Kim-1 in chronic renal damage and effects of antiproteinuric treatment on Kim-1 are unknown. We studied Kim-1 in adriamycin nephrosis (AN) before and after renin-angiotensin system blockade. A renal biopsy was taken 6 wk after adriamycin injection to study renal damage and Kim-1 expression. Subsequently, ACE inhibition (ACEi; n = 23), angiotensin II antagonist (AT(1A); n = 23), or vehicle (n = 10) was given for 6 wk; healthy rats served as controls (CON; n = 8). In AN, renal Kim-1 mRNA was induced 26-fold vs. CON at week 6, with further increase in vehicle to week 12 (40-fold) but was reduced by ACEi and AT(1A) to 10- and 12-fold vs. CON (P < 0.05 vs. week 6). Kim-1 protein was undetectable in CON; in AN, it was present in brush border of dilated tubules in areas with adjacent interstitial lesions. Renal Kim-1 protein levels increased from weeks 6-12 in vehicle and decreased in ACEi- and AT(1A)-treated groups (P < 0.05). In vehicle, urinary Kim-1 was increased (P < 0.05 vs. CON), with a reduction by ACEi and AT(1A) (P < 0.05 vs. vehicle). Renal and urinary Kim-1 correlated with proteinuria and interstitial damage cross-sectionally. Reductions in proteinuria and renal Kim-1 correlated, which was not associated by corresponding changes in tubulointerstitial fibrosis. In conclusion, on longitudinal follow-up during antiproteinuric treatment increased renal Kim-1 expression is reversible in proportion to proteinuria reduction, likely reflecting reversibility of early tubular injury, supporting its potential as a biomarker for tubulointerstitial processes of damage and repair.
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- 2009
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20. Signal transduction pathways involved in brain death-induced renal injury.
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Bouma HR, Ploeg RJ, and Schuurs TA
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- Blood-Brain Barrier physiology, Chemokines biosynthesis, Chemokines genetics, Endothelium, Vascular pathology, Extracellular Signal-Regulated MAP Kinases metabolism, Humans, Inflammation genetics, Inflammation pathology, Inflammation physiopathology, Kidney Transplantation mortality, Neurons pathology, Transcription, Genetic, Brain Death, Kidney injuries, Kidney pathology, Kidney Transplantation statistics & numerical data, Signal Transduction, Tissue Donors
- Abstract
Kidneys derived from brain death organ donors show an inferior survival when compared to kidneys derived from living donors. Brain death is known to induce organ injury by evoking an inflammatory response in the donor. Neuronal injury triggers an inflammatory response in the brain, leading to endothelial dysfunction and the release of cytokines in the circulation. Serum levels of interleukin-6, -8, -10, and monocyte chemoattractant protein-1 (MCP-1) are increased after brain death. Binding with cytokine-receptors in kidneys stimulates activation of nuclear factor-kappa B (NF-kappaB), selectins, adhesion molecules and production of chemokines leading to cellular influx. Mitogen-activated protein kinases (MAP-kinases) mediate inflammatory responses and together with NF-kappaB they seem to play an important role in brain death induced renal injury. Altering the activation state of MAP-kinases could be a promising drug target for early intervention to reduce cerebral injury related donor kidney damage and improve outcome after transplantation.
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- 2009
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21. The role of bile salt toxicity in the pathogenesis of bile duct injury after non-heart-beating porcine liver transplantation.
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Yska MJ, Buis CI, Monbaliu D, Schuurs TA, Gouw AS, Kahmann ON, Visser DS, Pirenne J, and Porte RJ
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- ATP Binding Cassette Transporter, Subfamily B biosynthesis, ATP Binding Cassette Transporter, Subfamily B genetics, ATP Binding Cassette Transporter, Subfamily B, Member 11, ATP-Binding Cassette Transporters biosynthesis, ATP-Binding Cassette Transporters genetics, Animals, Bile Acids and Salts metabolism, Biopsy, Cholestasis, Intrahepatic metabolism, Cholestasis, Intrahepatic mortality, Disease Models, Animal, Female, Gene Expression, Liver Transplantation mortality, Liver Transplantation pathology, RNA, Messenger genetics, Reverse Transcriptase Polymerase Chain Reaction, Risk Factors, Severity of Illness Index, Survival Rate, Swine, Bile Acids and Salts toxicity, Bile Ducts, Intrahepatic injuries, Cholestasis, Intrahepatic etiology, Liver Transplantation adverse effects
- Abstract
Background: Intrahepatic bile duct strictures are a serious complication after non-heart-beating (NHB) liver transplantation. Bile salt toxicity has been identified as an important factor in the pathogenesis of bile duct injury and cholangiopathies. The role of bile salt toxicity in the development of biliary strictures after NHB liver transplantation is unclear., Methods: In a porcine model of NHB liver transplantation, we studied the effect of different periods of warm ischemia in the donor on bile composition and subsequent bile duct injury after transplantation. After induction of cardiac arrest in the donor, liver procurement was delayed for 0 min (group A), 15 min (group B), or more or equal to 30 min (group C). Livers were subsequently transplanted after 4 hr of cold preservation. In the recipients, bile flow was measured, and bile samples were collected daily to determine the bile salt-to-phospholipid ratio. Severity of bile duct injury was semiquantified by using a histologic grading scale., Results: Posttransplantation survival was directly related to the duration of warm ischemia in the donor. The bile salt-to-phospholipid ratio in bile produced early after transplantation was significantly higher in group C, compared with group A and B. Histopathologic condition showed the highest degree of bile duct injury in group C., Conclusion: Prolonged warm ischemia in NHB donors is associated with the formation of toxic bile after transplantation, with a high biliary bile salt-to-phospholipid ratio. These data suggest that bile salt toxicity contributes to the pathogenesis of bile duct injury after NHB liver transplantation.
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- 2008
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22. Static cold storage preservation of ischemically damaged kidneys. a comparison between IGL-1 and UW solution.
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Maathuis MH, Ottens PJ, van Goor H, Zwaagstra JJ, Wiersema-Buist J, Schuurs TA, Ploeg RJ, and Leuvenink HG
- Subjects
- Adenosine pharmacology, Allopurinol pharmacology, Animals, Cold Temperature, Glomerular Filtration Rate, Glutathione pharmacology, Insulin pharmacology, Kidney Tubules, Proximal pathology, Male, Proteinuria etiology, Raffinose pharmacology, Rats, Rats, Inbred Lew, Reactive Oxygen Species, Ischemia physiopathology, Kidney blood supply, Kidney Transplantation, Organ Preservation, Organ Preservation Solutions pharmacology
- Abstract
Especially in damaged organs, adequate organ preservation is critically important to maintain viability. Institut Georges Lopez-1 (IGL-1) is a new preservation solution, with an extracellular sodium/potassium ratio and polyethylene glycol as a colloid. The influence of warm and cold ischemia was evaluated in a rat Lewis-Lewis transplant model with a follow up of 14 days. Eight groups of donation after cardiac death donor kidneys were studied with warm ischemia of 0 and 15 min followed by 0- or 24-h cold storage (CS) preservation in IGL-1 or UW-CSS. Blood was collected daily during the first week and at day 14. Recipients were placed in metabolic cages at day 4 and 14 after transplantation allowing urine collection and adequate measurement of glomerular filtration rate. Focussing on inflammation, reactive oxygen species production, proximal tubule damage, proteinuria, histology, and renal function after transplantation we could not show any relevant difference between IGL-1 and UW-CSS. Furthermore, the combination of 15-min warm ischemia and by 24-h cold ischemia did not result in life sustaining kidney function after transplantation, irrespective of the used solution. In the present experiment, static CS preservation of ischemically damaged rat kidneys in either IGL-1 or UW-CSS rendered equal results after transplantation.
- Published
- 2008
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23. Early events in kidney donation: progression of endothelial activation, oxidative stress and tubular injury after brain death.
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Morariu AM, Schuurs TA, Leuvenink HG, van Oeveren W, Rakhorst G, and Ploeg RJ
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- Brain Injuries mortality, Brain Injuries pathology, Brain Injuries physiopathology, Endothelium, Vascular physiology, Endothelium, Vascular physiopathology, Humans, Kidney Tubules physiology, Brain Death, Kidney, Kidney Tubules pathology, Oxidative Stress, Postmortem Changes, Tissue Donors, Tissue and Organ Procurement methods
- Abstract
Cerebral injury leading to brain death (BD) causes major physiologic derangements in potential organ donors, which may result in vascular-endothelial activation and affect posttransplant graft function. We investigated the kinetic of pro-coagulatory and pro-inflammatory endothelial activation and the subsequent oxidative stress and renal tubular injury, early after BD declaration. BD was induced by slowly inflating a balloon-catheter inserted in the extradural space over a period of 30 min. Rats (n = 30) were sacrificed 0.5, 1, 2 or 4 h after BD-induction and compared with sham-controls. This study demonstrates immediate pro-coagulatory and pro-inflammatory activation of vascular endothelium after BD in kidney donor rats, proportional with the duration of BD. E- and P-Selectins, Aalpha/Bbeta-fibrinogen mRNA were abruptly and progressively up-regulated from 0.5 h BD onwards; P-Selectin membrane protein expression was increased; fibrinogen was primarily visualized in the peritubular capillaries. Plasma von Willebrand factor was significantly higher after 2 h and 4 h BD. Urine heart-fatty-acid-binding-protein and N-acetyl-glucosaminidase, used as new specific and sensitive markers of proximal and distal tubular damage, were found significantly increased after 0.5 h, with a maximum at 4 h. Unexpectedly, oxidative stress was detectable only late, after the installation of tubular injury, suggesting only a secondary role for hypoxia in triggering these injuries.
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- 2008
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24. Complement and renal transplantation: from donor to recipient.
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Damman J, Schuurs TA, Ploeg RJ, and Seelen MA
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- Brain Death, Humans, Tissue Donors, Complement System Proteins physiology, Kidney Transplantation physiology
- Abstract
Long-term kidney graft survival is affected by different variables including donor condition, ischemia-reperfusion injury, and graft rejection during the transplantation process. The complement system is an important mediator of renal ischemia-reperfusion injury and in rejecting allografts. However, donor complement C3 seems to be crucial in renal transplantation-related injury as renal injury is attenuated in C3 deficient kidney grafts. Interestingly, before ischemia-reperfusion induced C3 expression, C3 is already induced in donors suffering from brain death. Therefore, strategies targeting complement activation in the brain-dead donor may increase graft viability and transplant outcome.
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- 2008
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25. Induction of kidney injury molecule-1 in homozygous Ren2 rats is attenuated by blockade of the renin-angiotensin system or p38 MAP kinase.
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de Borst MH, van Timmeren MM, Vaidya VS, de Boer RA, van Dalen MB, Kramer AB, Schuurs TA, Bonventre JV, Navis G, and van Goor H
- Subjects
- Aldosterone metabolism, Angiotensin II Type 1 Receptor Blockers pharmacology, Animals, Animals, Genetically Modified, Atrial Natriuretic Factor drug effects, Atrial Natriuretic Factor physiology, Benzimidazoles pharmacology, Biomarkers, Biphenyl Compounds, Blood Pressure physiology, Creatinine metabolism, Enzyme Inhibitors pharmacology, Enzyme-Linked Immunosorbent Assay, Fibrosis, Immunohistochemistry, Male, Nephritis, Interstitial metabolism, Nephritis, Interstitial pathology, Osteopontin biosynthesis, Rats, Rats, Inbred Strains, Reverse Transcriptase Polymerase Chain Reaction, Tetrazoles pharmacology, Cell Adhesion Molecules biosynthesis, Membrane Proteins biosynthesis, Renin genetics, Renin-Angiotensin System drug effects, p38 Mitogen-Activated Protein Kinases antagonists & inhibitors
- Abstract
Kidney injury molecule-1 (Kim-1) is associated with ischemic and proteinuric tubular injury; however, whether dysregulation of the renin-angiotensin system (RAS) can also induce Kim-1 is unknown. We studied Kim-1 expression in homozygous Ren2 rats, characterized by renal damage through excessive RAS activation. We also investigated whether antifibrotic treatment (RAS blockade or p38 MAP kinase inhibition) would affect Kim-1 expression. At 7 wk of age, homozygous Ren2 rats received a nonhypotensive dose of candesartan (0.05 mg x kg(-1) x day(-1) sc) or the p38 inhibitor SB-239063 (15 mg x kg(-1) x day(-1) sc) for 4 wk; untreated Ren2 and Sprague-Dawley (SD) rats served as controls. Kim-1 mRNA and protein expression were determined by quantitative PCR and immunohistochemistry, respectively, and related to markers of prefibrotic renal damage. Urinary Kim-1 was measured in 8-wk-old Ren2 and SD rats with and without angiotensin-converting enzyme inhibition (ramipril, 1 mg x kg(-1) x day(-1) in drinking water for 4 wk). Untreated Ren2 rats showed a >20-fold increase in renal Kim-1 mRNA (expressed as Kim-1-to-GAPDH ratio): 75.5 +/- 43.6 vs. 3.1 +/- 1.0 in SD rats (P < 0.01). Candesartan and SB-239063 strongly reduced Kim-1 mRNA: 3.1 +/- 1.5 (P < 0.01) and 9.8 +/- 4.2 (P < 0.05), respectively. Kim-1 protein expression in damaged tubules paralleled mRNA expression. Kim-1 expression correlated with renal osteopontin, alpha-smooth muscle actin, and collagen III expression and with tubulointerstitial fibrosis. Damaged tubular segments expressing activated p38 also expressed Kim-1. Urinary Kim-1 was increased in Ren2 vs. SD (458 +/- 70 vs. 27 +/- 2 pg/ml, P < 0.01) rats and abolished in Ren2 rats treated with ramipril (33 +/- 5 pg/ml, P < 0.01). Kim-1 is associated with development of RAS-mediated renal damage. Antifibrotic treatment through RAS blockade or p38 MAP kinase inhibition reduced Kim-1 in the homozygous Ren2 model.
- Published
- 2007
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26. Time-dependent changes in donor brain death related processes.
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Schuurs TA, Morariu AM, Ottens PJ, 't Hart NA, Popma SH, Leuvenink HG, and Ploeg RJ
- Subjects
- Animals, Cytokines genetics, DNA Primers, Family, Inflammation genetics, Kinetics, Models, Animal, Oxidative Stress, Polymerase Chain Reaction, Rats, Rats, Inbred F344, Time Factors, Brain Death, Kidney, Kidney Transplantation physiology, Postmortem Changes, Tissue Donors
- Abstract
Donor brain death (BD) affects kidney function and survival after transplantation. Studies on brain dead kidney donors indicate that, besides inflammation and coagulation, cytoprotective gene expression is activated as well. Here, we evaluated in a time-course experiment progression of these renal BD-related processes. Animals were sacrificed 0.5, 1, 2 or 4 h after BD and compared to sham-operated controls. Proinflammatory genes (E-selectin, MCP-1, II-6) were massively up-regulated (p < 0.05) already 0.5 h after BD. Inducers of proinflammatory gene expression were either activated (NF-kappaB) or induced in expression (Egr-1) after 0.5 h of BD. Increased numbers of infiltrating granulocytes were seen in the interstitium from 0.5 h on. Also, expression of protective genes HO-1 and HSP70 were increased within 0.5 h. Remarkably, reactive oxygen species formation was detectable only in the later phase of BD. Among 14 measured serum cytokines, MCP-1 and KC-protein were significantly elevated from 0.5 h on. In conclusion, a fast induction of proinflammatory and stress-induced protective processes in brain dead donor kidneys was demonstrated, probably triggered by changes occurring during BD induction. Importantly, hypoxia appeared not to be one of the initial triggers, and early increased systemic levels of chemokines MCP-1 and KC may be regarded as the starting point for the inflammatory cascade in brain dead donor kidneys.
- Published
- 2006
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27. Spatiotemporal expression of heme oxygenase-1 detected by in vivo bioluminescence after hepatic ischemia in HO-1/Luc mice.
- Author
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Su H, van Dam GM, Buis CI, Visser DS, Hesselink JW, Schuurs TA, Leuvenink HG, Contag CH, and Porte RJ
- Subjects
- Animals, Feasibility Studies, Heme Oxygenase-1 genetics, Immunohistochemistry methods, Luciferases genetics, Male, Mice, Mice, Transgenic, RNA, Messenger metabolism, Reperfusion Injury enzymology, Staining and Labeling, Time Factors, Tissue Distribution, Warm Ischemia, Heme Oxygenase-1 metabolism, Ischemia enzymology, Liver blood supply, Liver enzymology, Luminescent Measurements
- Abstract
Upregulation of heme oxygenase-1 (HO-1) has been proposed as a critical mechanism protecting against cellular stress during liver transplantation, providing a potential target for new therapeutic interventions. We investigated the feasibility of in vivo bioluminescence imaging (BLI) to noninvasively quantify the spatiotemporal expression of HO-1 after warm hepatic ischemia in living animals. Luciferase activity was measured by BLI as an index of HO-1 transcription in transgenic reporter mice (Ho1-luc) at standardized time points after 60 minutes of warm hepatic ischemia. HO-1 mRNA levels were measured in postischemic livers of mice sacrificed at the same time points in separate experiments. Bioluminescent signals from postischemic liver lobes were first detected at 3 hours after reperfusion. Peak levels were reached at 9 hours, after which bioluminescent activity declined and returned to baseline values at 48 hours after reperfusion. Upregulation of HO-1 as detected by in vivo BLI was preceded by increased HO-1 mRNA expression and confirmed by enhanced immunohistochemical staining of hepatocytes. In conclusion, this study shows that in vivo BLI allows a sensitive assessment of HO-1 expression after hepatic ischemia in living animals. The capability of whole-body temporal imaging of HO-1 expression provides a valuable tool in the development of novel strategies to modulate HO-1 expression in liver transplantation., ((c) 2006 AASLD)
- Published
- 2006
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28. Matrix metalloproteinases as profibrotic factors in terminal ileum in Crohn's disease.
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Warnaar N, Hofker HS, Maathuis MH, Niesing J, Bruggink AH, Dijkstra G, Ploeg RJ, and Schuurs TA
- Subjects
- Adult, Constriction, Pathologic enzymology, Constriction, Pathologic pathology, Crohn Disease genetics, Crohn Disease surgery, Female, Gene Expression Regulation, Enzymologic, Humans, Ileum surgery, Interleukin-16 biosynthesis, Male, Matrix Metalloproteinase 1 biosynthesis, Matrix Metalloproteinase 1 genetics, Matrix Metalloproteinase 3 biosynthesis, Matrix Metalloproteinase 3 genetics, Matrix Metalloproteinases genetics, Middle Aged, RNA, Messenger biosynthesis, RNA, Messenger genetics, Recurrence, Tissue Inhibitor of Metalloproteinase-1 biosynthesis, Tissue Inhibitor of Metalloproteinase-1 genetics, Transforming Growth Factor beta biosynthesis, Tumor Necrosis Factor-alpha biosynthesis, Up-Regulation, Crohn Disease enzymology, Crohn Disease pathology, Ileum enzymology, Ileum pathology, Matrix Metalloproteinases biosynthesis
- Abstract
Background: Returning stenosis in Crohn's disease (CD) patients is poorly understood. After resection, newly developed strictures are seen within 10 years in 50% to 70%. Matrix metalloproteinases (MMPs) are involved in matrix-turnover processes. This study analyzes spatial expression of MMP-1, MMP-3, MMP-9, tissue inhibitor of MMP-1, and collagen III to get better insight in tissue remodeling of terminal ileum of CD patients., Methods: Expressions were analyzed on mRNA and the protein level (MMP-1, MMP-3) in segments from resected terminal ileum from CD and control patients. In CD, macroscopic distinction was made between proximal resection margin, prestenotic, and stenotic tissue. Immunohistochemistry allowed for expression analyses transmurally., Results: MMP-1 and MMP-3 gene expression was up-regulated (P < 0.05) in both prestenotic and stenotic tissue. MMP-1 protein was significantly up-regulated in submucosal and muscular tissue of prestenotic parts and in muscular tissue of stenotic Crohn samples. MMP-3 protein was significantly up-regulated in all layers of prestenotic and stenotic Crohn samples. Even in submucosa of proximal resection margin tissue, MMP-3 expression was significantly higher than in controls., Conclusion: Surprisingly, in proximal resection margin tissue up-regulated MMP-3 was seen. This suggests that in nonresected terminal ileum, in which anastomosis is made, tissue turnover is present, which may account for the high recurrence of intestinal strictures.
- Published
- 2006
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29. Tubular kidney injury molecule-1 in protein-overload nephropathy.
- Author
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van Timmeren MM, Bakker SJ, Vaidya VS, Bailly V, Schuurs TA, Damman J, Stegeman CA, Bonventre JV, and van Goor H
- Subjects
- Animals, Blotting, Western, Cell Adhesion Molecules analysis, Cell Adhesion Molecules genetics, Cell Adhesion Molecules urine, Gene Expression Regulation, Immunohistochemistry, Kidney Diseases pathology, Kidney Tubules chemistry, Kidney Tubules pathology, Male, Membrane Proteins analysis, Membrane Proteins genetics, Membrane Proteins urine, Proteinuria physiopathology, RNA, Messenger analysis, RNA, Messenger genetics, Rats, Rats, Wistar, Vimentin analysis, Cell Adhesion Molecules physiology, Kidney Diseases etiology, Kidney Diseases physiopathology, Kidney Tubules physiopathology, Membrane Proteins physiology, Proteinuria complications
- Abstract
Kim-1, a recently discovered membrane protein, is undetectable in normal kidneys but markedly induced in proximal tubules after ischemic and toxic injury. The function of Kim-1 is unclear, but it is implicated in damage/repair processes. The Kim-1 ectodomain is cleaved by metalloproteinases and detectable in urine. We studied Kim-1 in a nontoxic, nonischemic, model of tubulointerstitial damage caused by acute proteinuria. Uninephrectomized (NX) rats received daily (ip) injections of 2 g BSA (NX+BSA, n = 12) or saline (NX, n = 6) for 3 wk. Kidneys were stained for various damage markers by immunohistochemistry (IHC). Kim-1 mRNA (RT-PCR, in situ hybridization), protein (IHC, Western blotting), and urinary Kim-1 (Luminex) were determined. Spatial relations between Kim-1 and other damage markers were studied by double labeling IHC. NX+BSA rats developed massive proteinuria (1,217 +/- 313 vs. 18 +/- 2 mg/day in NX, P < 0.001) and significant renal damage. Kim-1 mRNA was upregulated eightfold in NX+BSA (ratio Kim-1/beta-actin, 4.08 +/- 2.56 vs. 0.52 +/- 0.64 in NX, P < 0.001) and localized to damaged tubules. Kim-1 protein expression was markedly induced in NX+BSA (2.46 +/- 1.19 vs. 0.39 +/- 0.10% staining/field in NX, P < 0.001). Urinary Kim-1 was significantly elevated in NX+BSA (921 +/- 592 vs. 87 +/- 164 pg/ml in NX, P < 0.001) and correlated with tissue Kim-1 expression (r = 0.66, P =0.02). Kim-1 protein was found at the apical membrane of dilated nephrons. Kim-1 expression was limited to areas with inflammation (MØ), fibrosis (alpha-smooth muscle actin), and tubular damage (osteopontin), and only occasionally with tubular dedifferentiation (vimentin). These results implicate involvement of Kim-1 in the pathogenesis of proteinuria-induced renal damage/repair. Urinary Kim-1 levels may serve as a marker of proteinuria-induced renal damage.
- Published
- 2006
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30. Renal expression of heat shock proteins after brain death induction in rats.
- Author
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Bos EM, Schuurs TA, Kraan M, Ottens PJ, van den Eijnden MM, Leuvenink HG, Kampinga HH, van Goor H, and Ploeg RJ
- Subjects
- Animals, Heme Oxygenase-1, Immunohistochemistry, Kidney enzymology, Male, Models, Animal, Rats, Rats, Inbred F344, Reverse Transcriptase Polymerase Chain Reaction, Brain Death, HSP70 Heat-Shock Proteins genetics, Heme Oxygenase (Decyclizing) genetics, Kidney physiology
- Abstract
The majority of transplanted kidneys are derived from brain-dead patients. This nonphysiological state influences the hemodynamic and hormonal status of the donor. As a result, kidneys derived from brain-dead donors have inferior graft survival and increased graft function loss. Heat shock proteins (HSPs) are a family of stress-inducible proteins involved in maintaining cell homeostasis and regulating the immune system. We studied renal expression of the genes HO-1, HSP27, HSP40, and HSP70 after experimental brain death in rats. Brain death was induced in male F344 rats by slowly inflating a balloon catheter in the epidural space. Untreated rats were used as controls. Animals were humanely killed after 4 hours of brain death. Kidneys were analysed using RT-PCR, Western blotting, and immunohistochemistry. RT-PCR showed an increase in expression of genes coding for HO-1 (3.6-fold; P < .05) and HSP70 (2.7-fold; P < .05) after brain death. Western blotting also revealed an increase in HO-1 protein levels (4.6-fold; P < .001) but changes in HSP70 protein expression were not detected. Immunohistochemistry showed increments of HO-1 protein expression in the renal cortical tubules of brain-dead rats. HSP70 was predominantly increased in renal distal tubules of brain-dead rats treated for hypotension. No changes were observed in renal HSP27 and HSP40 expression after brain death. Renal stress caused by brain death induces expression of the cytoprotective genes HO-1 and HSP70, but not of HSP27 and HSP40. The up-regulation of these cytoprotective genes could be part of a recuperative mechanism induced by stress associated with brain death.
- Published
- 2005
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31. Effects of brain death on stress and inflammatory response in the human donor kidney.
- Author
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Nijboer WN, Schuurs TA, van der Hoeven JA, Leuvenink HG, van der Heide JJ, van Goor H, and Ploeg RJ
- Subjects
- Biopsy, Chemokine CCL2 genetics, E-Selectin genetics, Follow-Up Studies, Gene Expression Regulation, HSP70 Heat-Shock Proteins genetics, Heme Oxygenase (Decyclizing) genetics, Heme Oxygenase-1, Humans, Immunohistochemistry, Kidney Transplantation pathology, Membrane Proteins, Nephrectomy, Reverse Transcriptase Polymerase Chain Reaction, Tissue and Organ Harvesting methods, Transforming Growth Factor beta genetics, Treatment Outcome, Brain Death, Inflammation physiopathology, Kidney Transplantation physiology, Living Donors, Tissue Donors
- Abstract
Background: After kidney transplantation, a decreased graft survival is seen in grafts from brain dead donors compared to living donors, possibly related to a progressive inflammatory reaction in the graft. In this study, we focused on the effects of brain death on the inflammatory response (adhesion molecules, leukocyte infiltration, and gene expression) and stress-related heat shock proteins in the human kidney. Research outcomes and clinical donor parameters were linked to outcome data after transplantation., Methods: Human kidney biopsy specimens were obtained during organ retrieval from brain dead and living organ donor controls. On these specimens, immunohistochemistry and semiquantitative RT-PCR were performed. Regression analyses were performed connecting results to outcome data of kidney recipients., Results: In brain death, immunohistochemistry showed an increase of E-selectin and interstitial leukocyte invasion versus controls; RT-PCR showed an increase of gene expression of HO-1 and Hsp70. One and 3 years after transplantation, high ICAM and VCAM expression proved to have a negative effect on kidney function in brain dead and living kidneys, while HO-1 proved to have a strongly positive effect, but only in kidneys from living donors., Conclusions: E-selectin expression and interstitial leukocyte accumulation in brain dead donor kidneys indicate an early phase inflammatory state prior to organ retrieval. Also, brain death causes a stress-related response resulting in upregulation of potentially protective heat shock proteins. The upregulation of HO-1 is beneficial in living donor kidneys, but might be inadequate in brain death.
- Published
- 2005
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32. Distinct transcriptional changes in donor kidneys upon brain death induction in rats: insights in the processes of brain death.
- Author
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Schuurs TA, Gerbens F, van der Hoeven JA, Ottens PJ, Kooi KA, Leuvenink HG, Hofstra RM, and Ploeg RJ
- Subjects
- Animals, Creatinine blood, Humans, L-Lactate Dehydrogenase blood, Male, Oligonucleotide Array Sequence Analysis, Potassium blood, RNA genetics, RNA isolation & purification, Rats, Rats, Wistar, Reverse Transcriptase Polymerase Chain Reaction, Sodium blood, Tissue Donors, Brain Death, Kidney physiology, Kidney Transplantation physiology, Transcription, Genetic
- Abstract
Brain death affects hormone regulation, inflammatory reactivity and hemodynamic stability. In transplant models, donor organs retrieved from brain dead (BD) rats suffer from increased rates of primary non-function and lower graft survival. To unravel the mechanisms behind brain death we have performed DNA microarray studies with kidney-derived RNA from normo- and hypotensive BD rats, corresponding with optimal and marginal BD donors, respectively. In kidneys from normotensive donors 63 genes were identified as either up- (55) or down-regulated (8), while 90 genes were differentially expressed (67 up-regulated) in hypotensive BD donor kidneys. Most genes were categorized in different functional groups: metabolism/transport (including the down-regulated water channel Aqp-2), inflammation/coagulation (containing the largest number (16) of up-regulated genes including selectins, Il-6, alpha- and beta-fibrinogen), cell division/fibrosis (including KIM-1 involved in tubular regeneration) and defense/repair (with the cytoprotective genes HO-1, Hsp70, MnSOD2). Also, genes encoding transcription factors (including immediate early genes as Atf-3, Egr-1) and proteins involved in signal transduction (Pik3r1) were identified. Summarizing, the use of DNA microarrays has clarified parts of the process of brain death: Brain-death-induced effects ultimately lead, via activation of transcription factors and signal transduction cascades, to differential expression of different "effector" genes. Not only deleterious processes such as inflammation and fibrosis occur in brain dead donor kidneys but genes involved in protection and early repair processes are activated as well. These findings can be used to introduce specific cytoprotective interventions in the brain dead donor to better maintain or even increase organ viability.
- Published
- 2004
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33. Effect of brain death on gene expression and tissue activation in human donor kidneys.
- Author
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Nijboer WN, Schuurs TA, van der Hoeven JA, Fekken S, Wiersema-Buist J, Leuvenink HG, Hofker S, Homan van der Heide JJ, van Son WJ, and Ploeg RJ
- Subjects
- Adult, Aged, Chemokine CCL2 genetics, Female, Gene Expression, HSP70 Heat-Shock Proteins genetics, Humans, Intercellular Adhesion Molecule-1 genetics, Male, Middle Aged, Transforming Growth Factor beta genetics, Tumor Necrosis Factor-alpha genetics, Brain Death metabolism, Kidney metabolism, Kidney Transplantation, Living Donors
- Abstract
Background: After kidney transplantation, decreased graft survival is seen in grafts from brain dead (BD) donors compared with living donors. This might result partly from a progressive nonspecific inflammation in the graft. In this study, we focused on the effects of BD on inflammatory response (adhesion molecules, leukocyte invasion, gene expression) and stress-related heat shock proteins in the human kidney. Research outcomes and clinical donor parameters were then linked to outcome data after transplantation., Methods: Kidney biopsy specimens and serum were obtained during organ retrieval from BD and living organ donor controls. Immunohistochemistry and semiquantitative reverse transcriptase-polymerase chain reaction were performed on the biopsy specimens. Clinical and laboratory parameters from BD donors were recorded and connected to outcome data of the recipients of the kidneys studied., Results: After brain death, immunohistochemistry showed an increase of E-selectin (P<0.01) and interstitial leukocyte invasion (P<0.05) compared with controls. Also, reverse transcriptase-polymerase chain reaction showed a threefold increased heme oxygenase-1 (P<0.05) and Hsp70 (P<0.01) gene expression after BD. Levels of monocyte chemotactic protein-1 and transforming growth factor-beta were twice as high after brain death but did not reach significance. Transplantation outcome was influenced by several donor variables: positively most notably by donor treatment with desmopressin and negatively by high serum urea levels during brain death and by high intercellular adhesion molecule and vascular cell adhesion molecule expression in the kidney. Heme oxygenase-1 proved to have a protective function, but only in kidneys from living donors., Conclusions: The presence of interstitial leukocytes and the early adhesion molecule E-selectin in BD donor kidneys indicates an early-phase inflammatory process during organ retrieval. Elevated levels of monocyte chemotactic protein-1 and transforming growth factor-beta suggest a role for monocytes/macrophages in this phase. We suggest that BD causes a stress-related response against which protective heat shock proteins are formed in the future graft. This stress response may be too severe to be fully counteracted by elevated heat shock proteins. Which systemic and/or local factors trigger brain death-related graft injury is currently under investigation.
- Published
- 2004
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34. Causes of limited survival of microencapsulated pancreatic islet grafts.
- Author
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de Groot M, Schuurs TA, and van Schilfgaarde R
- Subjects
- Alginates administration & dosage, Cell Hypoxia, Humans, Polylysine administration & dosage, Graft Survival, Islets of Langerhans Transplantation adverse effects, Islets of Langerhans Transplantation mortality
- Abstract
Successful transplantation of pancreatic tissue has been demonstrated to be an efficacious method of restoring glycemic control in type 1 diabetic patients. To establish graft acceptance patients require lifelong immunosuppression, which in turn is associated with severe deleterious side effects. Microencapsulation is a technique that enables the transplantation of pancreatic islets in the absence of immunosuppression by protecting the islet tissue through a mechanical barrier. This protection may even allow for the transplantation of animal tissue, which opens the perspective of using animal donors as a means to solve the problem of organ shortage. Microencapsulation is not yet applied in clinical practice, mainly because encapsulated islet graft survival is limited. In the present review we discuss the principal causes of microencapsulated islet graft failure, which are related to a lack of biocompatibility, limited immunoprotective properties, and hypoxia. Next to the causes of encapsulated islet graft failure we discuss possible improvements in the encapsulation technique and additional methods that could prolong encapsulated islet graft survival. Strategies that may well support encapsulated islet grafts include co-encapsulation of islets with Sertoli cells, the genetic modification of islet cells, the creation of an artificial implantation site, and the use of alternative donor sources. We conclude that encapsulation in combination with one or more of these additional strategies may well lead to a simple and safe transplantation therapy as a cure for diabetes.
- Published
- 2004
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35. Rat islet isolation yield and function are donor strain dependent.
- Author
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de Groot M, de Haan BJ, Keizer PP, Schuurs TA, van Schilfgaarde R, and Leuvenink HG
- Subjects
- 1-Methyl-3-isobutylxanthine pharmacology, Animals, Culture Techniques, Glucose pharmacology, Insulin metabolism, Insulin Secretion, Islets of Langerhans cytology, Islets of Langerhans metabolism, Islets of Langerhans Transplantation methods, Male, Rats, Rats, Inbred Lew, Rats, Sprague-Dawley, Rats, Wistar, Specific Pathogen-Free Organisms, Islets of Langerhans physiology
- Abstract
Effective rat islet isolation is pertinent for successful islet transplantation and islet studies in vitro. To determine which rat strain yields the highest number of pure and functional islets, four commonly used rat strains were compared with regard to islet yield, islet purity and islet function. Secretory responses were assessed by stimulation with glucose, and by stimulation with glucose plus 3-isobutyl-1-methylxanthine (IBMX). We show that rat islet function and isolation yield are donor strain dependent. Albino Oxford (AO) rats donated twice as many islets than Wistar, Lewis and Sprague Dawley (SD) rats. Stimulation with glucose plus IBMX resulted in an average five-fold increase of the stimulation index of AO, Lewis, Wistar and SD rats compared to stimulation with glucose only. AO islets had improved secretory responses after a one-week culture period, but required the addition of IBMX to glucose to elicit a distinguished stimulated insulin secretion after 2 days of culture. Islets from SD rats showed inferior results with regard to purity immediately after isolation and with regard to function after short- and after long-time culture. Because Lewis islets possessed the highest secretory response to glucose (without IBMX) immediately after isolation, Lewis rats may be preferred as islet donors for immediate use. The addition of IBMX to glucose for in vitro functional testing is recommended because it elicits high insulin secretory responses of islets regardless of the rat strain. AO rats are preferred for culture experiments since the number of experimental animals is reduced two-fold compared to Lewis, Wistar and SD rats.
- Published
- 2004
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36. Macrophage overgrowth affects neighboring nonovergrown encapsulated islets.
- Author
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de Groot M, Schuurs TA, Leuvenink HG, and van Schilfgaarde R
- Subjects
- Animals, Capsules, Cell Division, Cell Survival, Interleukin-1 metabolism, Islets of Langerhans physiology, Male, Nitric Oxide Synthase genetics, Nitric Oxide Synthase Type II, Nitrites metabolism, Peritoneum, Proto-Oncogene Proteins genetics, Proto-Oncogene Proteins c-bcl-2 genetics, RNA, Messenger analysis, Rats, Rats, Inbred Strains, Tumor Necrosis Factor-alpha metabolism, bcl-2-Associated X Protein, Graft Survival, Islets of Langerhans cytology, Islets of Langerhans Transplantation, Macrophages cytology
- Abstract
Background: Encapsulation significantly prolongs islet graft survival in the absence of immunosuppression. However, encapsulated islet graft survival is limited to periods of several months. Part of the encapsulated islet graft is affected by a nonprogressive pericapsular overgrowth. To investigate whether macrophages on overgrown capsules affect neighboring nonovergrown encapsulated islets, encapsulated islets were studied during coculture., Materials and Methods: Encapsulated islet function, islet vitality, and islet cell replication were assessed, as well as the mRNA expression of Bcl-2, Bax, inducible nitric oxide synthase, and monocyte chemoattractant protein-1 in encapsulated islets after 48 h of culture together with microcapsules with macrophage overgrowth. Overgrown capsules were retrieved from the rat peritoneum, three weeks after implantation of an encapsulated islet graft., Results: Coculture was associated with inhibition of the stimulated insulin secretion, with decreased cell replication, and with increased cell necrosis, but not with apoptosis of encapsulated islet cells. mRNA expression levels in encapsulated islets after coculture were not different from controls, except for a decrease in Bax mRNA. We found a high level of nitrite, as an indicator of nitric oxide production, but not an increase in inducible nitric oxide synthase mRNA in islets. This, in combination with the absence of increase in monocyte chemoattractant protein-1 mRNA and the lack of apoptosis, indicates that neither interleukin-1beta nor tumor necrosis factor-alpha was responsible for the deleterious effects of coculture on encapsulated islets., Conclusions: Nonovergrown encapsulated islets are affected by the overgrowth on encapsulated islets in their close proximity. This overgrowth contains macrophages that produce nitric oxide which, rather than cytokines, may be held responsible for the deleterious effect on the neighboring encapsulated islets.
- Published
- 2003
- Full Text
- View/download PDF
37. Effective removal of alginate-poly-L-lysine microcapsules from pancreatic islets by use of trypsin-EDTA.
- Author
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de Groot M, Leuvenink HG, Keizer PP, Fekken S, Schuurs TA, and van Schilfgaarde R
- Subjects
- Animals, Glucose metabolism, Islets of Langerhans metabolism, Male, Rats, Rats, Wistar, Reverse Transcriptase Polymerase Chain Reaction, Alginates pharmacokinetics, Capsules pharmacokinetics, Edetic Acid pharmacology, Islets of Langerhans drug effects, Polylysine analogs & derivatives, Polylysine pharmacokinetics, Trypsin pharmacokinetics
- Abstract
Although the transplantation of alginate-poly-L-lysine-alginate encapsulated islets of Langerhans usually is successful, graft survival is still limited. Molecular analysis by RT-PCR of the encapsulated islets may provide insight into the mechanisms that affect islets during graft failure. However, RT-PCR on encapsulated islets is not possible because the poly-L-lysine of the capsule interferes with both cDNA synthesis and PCR amplification. We applied a method that mechanically removes the microcapsules from the islets after a short trypsin-EDTA treatment (decapsulation), thereby enabling RT-PCR analysis. The results of this study show that the decapsulation procedure does not affect islet vitality and has only minor effects on islet function and morphology. The decapsulation does not affect GAPDH, beta-actin, Bcl-2, or Bax gene expression. This method is an improvement over the time-consuming manual dissection of microcapsules because it allows for the rapid and relatively harmless removal of capsules on a larger scale. Decapsulation offers the possibility of applying RT-PCR, as well as other methods, which cannot be performed on encapsulated islets., (Copyright 2003 Wiley Periodicals, Inc.)
- Published
- 2003
- Full Text
- View/download PDF
38. Response of Encapsulated Rat Pancreatic Islets to Hypoxia.
- Author
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de Groot M, Schuurs TA, Keizer PPM, Fekken S, Leuvenink HGD, and Van Schilfgaarde R
- Abstract
Hypoxia contributes to encapsulated pancreatic islet graft failure. To gain insight into the mechanisms that lead to hypoxia-induced graft failure, encapsulated islet function, vitality, and cell replication were assessed after 2 and 5 days of hypoxic (1% O
2 ) and normoxic (20% O2 ) culture. The mRNA expression levels of Bcl-2, Bax, inducible nitric oxide synthase (iNOS), and monocyte chemoattractant protein 1 (MCP-1) were assessed, as well as the amount of nitrite and MCP-1 in the culture medium. Hypoxia was associated with loss of encapsulated islet function and vitality, but not with an increase in islet cell replication. Loss of vitality was due to necrosis, and only modestly due to apoptosis. Hypoxia was not associated with changes in the Bcl-2/Bax mRNA ratio, but it did increase the expression of iNOS and MCP-1 mRNA. The increased mRNA levels were, however, not associated with elevated concentrations of nitrite nor with elevated levels of MCP-1 protein. The increased iNOS mRNA levels imply a role for NO in the completion of cell death by hypoxia. The increased MCP-1 mRNA levels suggest that encapsulated islets in vivo contribute to their own graft failure by attracting cytokine-producing macrophages. The discrepancy between iNOS mRNA and nitrite is explained by the longer half-life of NO during hypoxia. MCP-1 protein levels are underestimated as a consequence of the lower number of vital cells in combination with a higher proteolytic activity due to necrosis. Thus, strategies to eliminate hypoxia may not only improve islet function and vitality, but may also reduce the attraction of macrophages by encapsulated islets.- Published
- 2003
- Full Text
- View/download PDF
39. Microcapsules and their ability to protect islets against cytokine-mediated dysfunction.
- Author
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de Groot M, Keizer PP, de Haan BJ, Schuurs TA, Leuvenink HG, van Schilfgaarde R, and de Vos P
- Subjects
- Animals, Insulin metabolism, Islets of Langerhans metabolism, Permeability, Pilot Projects, Rats, Rats, Wistar, Graft Rejection prevention & control, Islets of Langerhans immunology, Islets of Langerhans Transplantation methods
- Published
- 2001
- Full Text
- View/download PDF
40. Sulfur regulation of the sulfate transporter genes sutA and sutB in Penicillium chrysogenum.
- Author
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van de Kamp M, Schuurs TA, Vos A, van der Lende TR, Konings WN, and Driessen AJ
- Subjects
- Carrier Proteins metabolism, Penicillium chrysogenum metabolism, Anion Transport Proteins, Carrier Proteins genetics, Cation Transport Proteins, Fungal Proteins, Penicillium chrysogenum genetics, Sulfates metabolism
- Abstract
Penicillium chrysogenum uses sulfate as a source of sulfur for the biosynthesis of penicillin. Sulfate uptake and the mRNA levels of the sulfate transporter-encoding sutB and sutA genes are all reduced by high sulfate concentrations and are elevated by sulfate starvation. In a high-penicillin-yielding strain, sutB is effectively transcribed even in the presence of excess sulfate. This deregulation may facilitate the efficient incorporation of sulfur into cysteine and penicillin.
- Published
- 2000
- Full Text
- View/download PDF
41. Sulfate transport in Penicillium chrysogenum: cloning and characterization of the sutA and sutB genes.
- Author
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van de Kamp M, Pizzinini E, Vos A, van der Lende TR, Schuurs TA, Newbert RW, Turner G, Konings WN, and Driessen AJ
- Subjects
- Amino Acid Sequence, Aspergillus nidulans genetics, Blotting, Northern, Cloning, Molecular, Gene Expression Regulation, Bacterial, Genetic Complementation Test, Molecular Sequence Data, Penicillium chrysogenum genetics, Physical Chromosome Mapping, Sequence Homology, Amino Acid, Time Factors, Anion Transport Proteins, Membrane Transport Proteins genetics, Membrane Transport Proteins metabolism, Penicillium chrysogenum metabolism, Sulfates pharmacokinetics
- Abstract
In industrial fermentations, Penicillium chrysogenum uses sulfate as the source of sulfur for the biosynthesis of penicillin. By a PCR-based approach, two genes, sutA and sutB, whose encoded products belong to the SulP superfamily of sulfate permeases were isolated. Transformation of a sulfate uptake-negative sB3 mutant of Aspergillus nidulans with the sutB gene completely restored sulfate uptake activity. The sutA gene did not complement the A. nidulans sB3 mutation, even when expressed under control of the sutB promoter. Expression of both sutA and sutB in P. chrysogenum is induced by growth under sulfur starvation conditions. However, sutA is expressed to a much lower level than is sutB. Disruption of sutB resulted in a loss of sulfate uptake ability. Overall, the results show that SutB is the major sulfate permease involved in sulfate uptake by P. chrysogenum.
- Published
- 1999
- Full Text
- View/download PDF
42. Positioning of nuclei in the secondary Mycelium of Schizophyllum commune in relation to differential gene expression.
- Author
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Schuurs TA, Dalstra HJ, Scheer JM, and Wessels JG
- Subjects
- Fungal Proteins genetics, Fungal Proteins metabolism, Immunohistochemistry, RNA, Fungal analysis, RNA, Fungal genetics, RNA, Messenger analysis, RNA, Messenger genetics, Schizophyllum growth & development, Schizophyllum ultrastructure, Cell Nucleus physiology, Gene Expression Regulation, Fungal, Genes, Fungal, Genes, Mating Type, Fungal, Schizophyllum genetics
- Abstract
In this paper we propose a novel type of gene regulation in the MATA|l4 MATB|l4 heterokaryon of Schizophyllum commune by means of differential positioning of the nuclei. It was found that binucleate hyphae with juxtaposed nuclei secrete SC4 hydrophobin (abundant during fruit-body formation), while SC3 (abundant during aerial hyphae formation in both mono- and dikaryons) appeared to be absent. Certain growth conditions disrupted the binucleate state in that the compatible nuclei became separated at a considerable distance. Under these conditions SC4 was not secreted while SC3 was secreted to a high degree. Disruption of the binucleate state was earlier observed in developing aerial hyphae which secrete SC3. Apparently, when the nuclei are in close proximity the dikaryon-expressed genes are switched on by interaction of the products of the MATA and MATB mating-type genes, while SC3 is suppressed by interacting products of the MATB genes, as occurs in the common MATA heterokaryon (MATA= MATB|l4). Growth conditions that lead to disruption of the binucleate state apparently result in abolishment of interaction between the MATB mating-type genes. Under these conditions, dikaryon-specific mRNAs do not accumulate in the MATA|l4 MATB|l4 heterokaryon, while SC3 mRNA becomes highly abundant., (Copyright 1998 Academic Press.)
- Published
- 1998
- Full Text
- View/download PDF
43. Homology-dependent silencing of the SC3 gene in Schizophyllum commune.
- Author
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Schuurs TA, Schaeffer EA, and Wessels JG
- Subjects
- Azacitidine pharmacology, Cell Nucleus metabolism, DNA Methylation, RNA, Messenger genetics, RNA, Messenger metabolism, Transcription, Genetic, Transformation, Genetic, Genes, Fungal, Schizophyllum genetics
- Abstract
After introduction of extra copies of the SC3 hydrophobin gene into a wild-type strain of Schizophyllum commune, gene silencing was observed acting on both endogenous and introduced SC3 genes in primary vegetative transformants. Nuclear run-on experiments indicated that silencing acted at the transcriptional level. Southern analysis revealed that cytosine methylation of genomic DNA occurred. Moreover, SC3 silencing was suppressed by exposure to 5-azacytidine during growth. After growth of SC3-suppressed colonies from homogenized mycelium or from colonies stored at 4 degrees, SC3 transcription was restored. However, after prolonged growth SC3 silencing was again observed. Introduction of a promoterless SC3 fragment into wild type gave less SC3 silencing.
- Published
- 1997
- Full Text
- View/download PDF
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