42 results on '"Phillips ARJ"'
Search Results
2. Redox status of acute pancreatitis as measured by cyclic voltammetry: initial rodent studies to assess disease severity.
- Author
-
Mittal A, Flint RJ, Fanous M, Delahunt B, Kilmartin PA, Cooper GJS, Windsor JA, and Phillips ARJ
- Published
- 2008
- Full Text
- View/download PDF
3. Polydopamine-Mediated Antimicrobial Lipopeptide Surface Coating for Medical Devices.
- Author
-
Lamba S, Wang K, Lu J, Phillips ARJ, Swift S, and Sarojini V
- Subjects
- Humans, Particle Size, Molecular Structure, Indoles chemistry, Indoles pharmacology, Polymers chemistry, Polymers pharmacology, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents chemistry, Anti-Bacterial Agents chemical synthesis, Coated Materials, Biocompatible chemistry, Coated Materials, Biocompatible pharmacology, Microbial Sensitivity Tests, Biofilms drug effects, Surface Properties, Materials Testing, Lipopeptides chemistry, Lipopeptides pharmacology
- Abstract
Biofilm formation on medical implants such as catheters is a major issue which needs to be addressed as it leads to severe health care associated infections. This study explored the design and synthesis of a polydopamine-lipopeptide based antimicrobial coating. The coating was used to modify the surface of Ultrathane Catheters. The lipopeptide SL1.15 with an N -terminal cysteine was covalently conjugated to the polydopamine modified catheters via a Michael addition reaction between the thiol moiety in the peptide and the aromatic ring in the polydopamine layer. The immobilization of the peptide on the polydopamine coated catheters was confirmed using water contact angle, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy (SEM). The antimicrobial activity of the coated catheters investigated using drug resistant and clinical strains of Gram-positive (MRSA and S. aureus ) and Gram-negative ( E. coli , A. baumannii , and P. aeruginosa ) bacteria revealed that lipopeptide immobilization inhibited >90% bacterial adhesion to the catheter surface. Additionally, biofilm assays against MRSA and E. coli revealed that the lipopeptide immobilized catheters inhibited >85% bacterial growth after 1 week incubation. Finally, the cytotoxicity profile of the catheters using the human dermal fibroblast, and the human embryonic kidney cell lines demonstrated that the polydopamine-lipopeptide coating was not toxic after 72 h incubation.
- Published
- 2024
- Full Text
- View/download PDF
4. Intestinal Lymphatic Biology, Drug Delivery, and Therapeutics: Current Status and Future Directions.
- Author
-
Reddiar SB, Xie Y, Abdallah M, Han S, Hu L, Feeney OM, Gracia G, Anshabo A, Lu Z, Farooq MA, Styles IK, Phillips ARJ, Windsor JA, Porter CJH, Cao E, and Trevaskis NL
- Subjects
- Humans, Animals, Intestines drug effects, Pharmaceutical Preparations administration & dosage, Pharmaceutical Preparations metabolism, Pharmaceutical Preparations chemistry, Drug Delivery Systems methods, Lymphatic System metabolism, Lymphatic System physiology
- Abstract
Historically, the intestinal lymphatics were considered passive conduits for fluids, immune cells, dietary lipids, lipid soluble vitamins, and lipophilic drugs. Studies of intestinal lymphatic drug delivery in the late 20th century focused primarily on the drugs' physicochemical properties, especially high lipophilicity, that resulted in intestinal lymphatic transport. More recent discoveries have changed our traditional view by demonstrating that the lymphatics are active, plastic, and tissue-specific players in a range of biological and pathological processes, including within the intestine. These findings have, in turn, inspired exploration of lymph-specific therapies for a range of diseases, as well as the development of more sophisticated strategies to actively deliver drugs or vaccines to the intestinal lymph, including a range of nanotechnologies, lipid prodrugs, and lipid-conjugated materials that "hitchhike" onto lymphatic transport pathways. With the increasing development of novel therapeutics such as biologics, there has been interest in whether these therapeutics are absorbed and transported through intestinal lymph after oral administration. Here we review the current state of understanding of the anatomy and physiology of the gastrointestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. We summarize the current state-of-the-art approaches to deliver drugs and quantify their uptake into the intestinal lymphatic system. Finally, and excitingly, we discuss recent examples of significant pharmacokinetic and therapeutic benefits achieved via intestinal lymphatic drug delivery. We also propose approaches to advance the development and clinical application of intestinal lymphatic delivery strategies in the future. SIGNIFICANCE STATEMENT: This comprehensive review details the understanding of the anatomy and physiology of the intestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. It highlights current state-of-the-art approaches to deliver drugs to the intestinal lymphatics and the shift toward the use of these strategies to achieve pharmacokinetic and therapeutic benefits for patients., (Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics.)
- Published
- 2024
- Full Text
- View/download PDF
5. Comment on Plutecki et al. The Anatomy of the Thoracic Duct and Cisterna Chyli: A Meta-Analysis with Surgical Implications. J. Clin. Med. 2024, 13 , 4285.
- Author
-
O'Hagan LA, Phillips ARJ, Windsor JA, and Mirjalili SA
- Abstract
We read, with interest, Plutecki and colleagues' systematic review of the anatomy of the thoracic duct and cisterna chyli, recently published in JCM [...].
- Published
- 2024
- Full Text
- View/download PDF
6. Lymphatic Uptake of a Highly Lipophilic Protease Inhibitor Prodrug from a Lipid-Based Formulation is Limited by Instability in the Intestine.
- Author
-
Xie Y, Lu Z, Styles IK, Reddiar SB, Phillips ARJ, Windsor JA, Porter CJH, Han S, and Trevaskis NL
- Subjects
- Dabigatran pharmacokinetics, Dabigatran chemistry, Lipids chemistry, Lymph metabolism, Drug Stability, Intestinal Mucosa metabolism, Emulsions, Animals, Protease Inhibitors pharmacokinetics, Protease Inhibitors administration & dosage, Protease Inhibitors chemistry, Male, Rats, Rats, Sprague-Dawley, Intestinal Absorption drug effects, Prodrugs pharmacokinetics, Prodrugs chemistry
- Abstract
Dabigatran etexilate (DABE) is a lipophilic double alkyl ester prodrug of dabigatran (DAB) which is a serine protease inhibitor used clinically as an anticoagulant. Recently, translocation of serine protease enzymes, including trypsin, from the gut into the mesenteric lymph and then blood has been associated with organ failure in acute and critical illnesses (ACIs). Delivery of DABE into mesenteric lymph may thus be an effective strategy to prevent organ failure in ACIs. Most drugs access the mesenteric lymph in low quantities following oral administration, as they are rapidly transported away from the intestine via the blood. Here, we examine the potential to deliver DABE into the mesenteric lymph by promoting association with lymph lipid transport pathways via co-administration with a lipid-based formulation (LBF). A series of self-emulsifying LBFs were designed and tested in vitro for their potential to form stable DABE loaded emulsions and keep DABE solubilised and stable over time in simulated gastrointestinal conditions. The LBFs were found to form fine emulsions with a droplet size of 214 ± 30 nm and DABE was stable in the formulation. The stability of DABE in vitro in simulated intestinal conditions, plasma and lymph samples was also evaluated to ensure stability in collected samples and to evaluate whether the prodrug is likely to release active DAB. Ultimately, a highly uniform and stable self-emulsifying Type III A LBF of DABE was chosen for progression into in vivo studies in male Sprague Dawley rats to confirm the lymphatic uptake and plasma pharmacokinetics. Both in vitro and in vivo in plasma and lymph, DABE was rapidly converted to an intermediate and DAB. The main species present in vivo in both plasma and lymph was DAB and mass transport of DABE and DAB in lymph was minimal (∼0.5 % of dose). Importantly, the concentration of DABE in lymph was substantially (20-176 fold) higher than in plasma, supporting that if the prodrug were stable and did not convert to DAB in the intestine, it would be lymphatically transported. Future studies will therefore focus on optimizing the design of the prodrug and formulation to improve stability during absorption and further promote lymphatic uptake., Competing Interests: Declaration of competing interest N.L. Trevaskis is an Editorial Board Member for Journal of Pharmaceutical Sciences and was not involved in the editorial review or the decision to publish this article. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: N.L. Trevaskis, C.J.H. Porter, S. Han are inventors of a lymph-directing glyceride prodrug technology that has been patented and licensed to PureTech Health, Boston. The current work is not related to the glyceride prodrug technology. It evaluates and describe lymphatic uptake of a lipophilic ester prodrug of different molecular structure., (Copyright © 2024 American Pharmacists Association. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
7. Computational fluid dynamic modeling of the lymphatic system: a review of existing models and future directions.
- Author
-
Jayathungage Don TD, Safaei S, Maso Talou GD, Russell PS, Phillips ARJ, and Reynolds HM
- Subjects
- Lymphatic System physiology, Computer Simulation, Physics, Hydrodynamics, Lymphatic Vessels physiology
- Abstract
Historically, research into the lymphatic system has been overlooked due to both a lack of knowledge and limited recognition of its importance. In the last decade however, lymphatic research has gained substantial momentum and has included the development of a variety of computational models to aid understanding of this complex system. This article reviews existing computational fluid dynamic models of the lymphatics covering each structural component including the initial lymphatics, pre-collecting and collecting vessels, and lymph nodes. This is followed by a summary of limitations and gaps in existing computational models and reasons that development in this field has been hindered to date. Over the next decade, efforts to further characterize lymphatic anatomy and physiology are anticipated to provide key data to further inform and validate lymphatic fluid dynamic models. Development of more comprehensive multiscale- and multi-physics computational models has the potential to significantly enhance the understanding of lymphatic function in both health and disease., (© 2023. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
8. Investigation of Staphylococcus aureus Biofilm-Associated Toxin as a Potential Squamous Cell Carcinoma Therapeutic.
- Author
-
Ong ZX, Kannan B, Phillips ARJ, and Becker DL
- Abstract
Cancer therapies developed using bacteria and their components have been around since the 19th century. Compared to traditional cancer treatments, the use of bacteria-derived compounds as cancer therapeutics could offer a higher degree of specificity, with minimal off-target effects. Here, we explored the use of soluble bacteria-derived toxins as a potential squamous cell carcinoma (SCC) therapeutic. We optimized a protocol to generate Staphylococcus aureus biofilm-conditioned media (BCM), where soluble bacterial products enriched in the development of biofilms were isolated from a bacterial culture and applied to SCC cell lines. Bioactive components of S. aureus ATCC 29213 (SA29213) BCM display selective toxicity towards cancerous human skin SCC-12 at low doses, while non-cancerous human keratinocyte HaCaT and fibroblast BJ-5ta are minimally affected. SA29213 BCM treatment causes DNA damage to SCC-12 and initiates Caspase 3-dependent-regulated cell death. The use of the novel SA29213 bursa aurealis transposon mutant library led to the identification of S. aureus alpha hemolysin as the main bioactive compound responsible for the observed SCC-12-specific toxicity. The antibody neutralisation of Hla eradicates the cytotoxicity of SA29213 BCM towards SCC-12. Hla displays high SCC-12-specific toxicity, which is exerted primarily through Hla-ADAM10 interaction, Hla oligomerisation, and pore formation. The high target specificity and potential to cause cell death in a controlled manner highlight SA29213 Hla as a good candidate as an alternative SCC therapeutic.
- Published
- 2024
- Full Text
- View/download PDF
9. Targeting Cx43 to Reduce the Severity of Pressure Ulcer Progression.
- Author
-
Kwek MSY, Thangaveloo M, Madden LE, Phillips ARJ, and Becker DL
- Subjects
- Mice, Animals, Connexin 43 metabolism, Connexins metabolism, Ischemia, Pressure Ulcer, HMGB1 Protein
- Abstract
In the skin, repeated incidents of ischemia followed by reperfusion can result in the breakdown of the skin and the formation of a pressure ulcer. Here we gently applied paired magnets to the backs of mice to cause ischemia for 1.5 h and then removed them to allow reperfusion. The sterile inflammatory response generated within 4 h causes a stage 1 pressure ulcer with an elevation of the gap junction protein Cx43 in the epidermis. If this process is repeated the insult will result in a more severe stage 2 pressure ulcer with a breakdown of the epidermis 2-3 days later. After a single pinch, the elevation of Cx43 in the epidermis is associated with the inflammatory response with an increased number of neutrophils, HMGB1 (marker of necrosis) and RIP3 (responsible for necroptosis). Delivering Cx43 specific antisense oligonucleotides sub-dermally after a single insult, was able to significantly reduce the elevation of epidermal Cx43 protein expression and reduce the number of neutrophils and prevent the elevation of HMGB1 and RIP3. In a double pinch model, the Cx43 antisense treatment was able to reduce the level of inflammation, necroptosis, and the extent of tissue damage and progression to an open wound. This approach may be useful in reducing the progression of stage 1 pressure ulcers to stage 2.
- Published
- 2023
- Full Text
- View/download PDF
10. Kidney Lymphatics.
- Author
-
Russell PS, Itkin M, Windsor JA, and Phillips ARJ
- Subjects
- Humans, Lymphatic System anatomy & histology, Kidney, Lymphangiogenesis physiology, Lymphatic Vessels
- Abstract
Following significant advances in lymphatic biology, the important role of kidney lymphatics in kidney function and dysfunction is now being more fully appreciated. Kidney lymphatics begin in the cortex as blind-ended lymphatic capillaries and then coalesce into larger lymphatics that follow the main blood vessels out through the kidney hilum. Their function in draining interstitial fluid, macromolecules, and cells underpins their important role in kidney fluid and immune homeostasis. This article provides a comprehensive overview of recent and more established research findings on kidney lymphatics and the implications of these findings for kidney function and disease. The use of lymphatic molecular markers has greatly expanded our knowledge of the development, anatomy, and pathophysiology of kidney lymphatics. Significant recent discoveries include the diverse embryological source of kidney lymphatics, the hybrid nature of the ascending vasa recta, and the effects of lymphangiogenesis on kidney diseases such as acute kidney injury and renal fibrosis. On the basis of these recent advances, there is now an opportunity to link information from across multiple research disciplines to drive a new era of lymphatic-targeted therapies for kidney disease. © 2023 American Physiological Society. Compr Physiol 13:4945-4984, 2023., (Copyright © 2023 American Physiological Society. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
11. The Anti-Tubercular Aminolipopeptide Trichoderin A Displays Selective Toxicity against Human Pancreatic Ductal Adenocarcinoma Cells Cultured under Glucose Starvation.
- Author
-
Kasim JK, Hong J, Hickey AJR, Phillips ARJ, Windsor JA, Harris PWR, Brimble MA, and Kavianinia I
- Abstract
Pancreatic ductal adenocarcinoma remains a highly debilitating condition with no effective disease-modifying interventions. In our search for natural products with promising anticancer activity, we identified the aminolipopeptide trichoderin A as a potential candidate. While it was initially isolated as an antitubercular peptide, we provide evidence that it is also selectively toxic against BxPC-3 and PANC-1 human pancreatic ductal adenocarcinoma cells cultured under glucose deprivation. This has critical implications for the pancreatic ductal adenocarcinoma, which is characterized by nutrient deprivation due to its hypovascularized network. We have also successfully simplified the trichoderin A peptide backbone, allowing greater accessibility to the peptide for further biological testing. In addition, we also conducted a preliminary investigation into the role of peptide lipidation at the N -terminus. This showed that analogues with longer fatty acyl chains exhibited superior cytotoxicity than those with shorter acyl chains. Further structural optimization of trichoderin A is anticipated to improve its biological activity, whilst ongoing mechanistic studies to elucidate its intracellular mechanism of action are conducted in parallel.
- Published
- 2023
- Full Text
- View/download PDF
12. The cisterna chyli: a systematic review of definition, prevalence, and anatomy.
- Author
-
Moazzam S, O'Hagan LA, Clarke AR, Itkin M, Phillips ARJ, Windsor JA, and Mirjalili SA
- Subjects
- Humans, Prevalence, Thoracic Duct diagnostic imaging, Thoracic Duct anatomy & histology
- Abstract
The cisterna chyli is a lymphatic structure found at the caudal end of the thoracic duct that receives lymph draining from the abdominal and pelvic viscera and lower limbs. In addition to being an important landmark in retroperitoneal surgery, it is the key gateway for interventional radiology procedures targeting the thoracic duct. A detailed understanding of its anatomy is required to facilitate more accurate intervention, but an exhaustive summary is lacking. A systematic review was conducted, and 49 published human studies met the inclusion criteria. Studies included both healthy volunteers and patients and were not restricted by language or date. The detectability of the cisterna chyli is highly variable, ranging from 1.7 to 98%, depending on the study method and criteria used. Its anatomy is variable in terms of location (vertebral level of T10 to L3), size (ranging 2-32 mm in maximum diameter and 13-80 mm in maximum length), morphology, and tributaries. The size of the cisterna chyli increases in some disease states, though its utility as a marker of disease is uncertain. The anatomy of the cisterna chyli is highly variable, and it appears to increase in size in some disease states. The lack of well-defined criteria for the structure and the wide variation in reported detection rates prevent accurate estimation of its natural prevalence in humans.
- Published
- 2022
- Full Text
- View/download PDF
13. Connexin43 in Post-Surgical Peritoneal Adhesion Formation.
- Author
-
Chua JW, Thangaveloo M, Lim DXE, Madden LE, Phillips ARJ, and Becker DL
- Abstract
Objective: Post-surgical peritoneal adhesions are a serious problem for the quality of life and fertility. Yet there are no effective ways of preventing their occurrence. The gap junction protein Cx43 is known to be involved in fibrosis in several different organs and disease conditions often associated with inflammation. Here we examined the Cx43 dynamic expression in an ischemic button model of surgical adhesions., Methods: Using the mouse ischemic button model, Cx43 antisense was delivered in Pluronic gel to attenuate Cx43 expression. The severity of button formation and immunofluorescence analysis of Cx43 and TGF-β1 were performed. The concentration of tissue plasminogen activator via ELISA was also performed., Results: As early as 6 h after button formation, the Cx43 levels were elevated in and around the button and some weak adhesions were formed. By 24 h Cx43 levels had increased further and adhesions were more defined. At 7 days the adhesions were much more robust, opaque, and vascularized, requiring blunt or sharp dissection to break them. Cx43 antisense attenuated its upregulation and, reduced the number and severity of adhesions that formed., Conclusion: Targeting Cx43 after surgical procedures may be a potential therapeutic strategy for preventing adhesion formation or at least reducing their severity., Competing Interests: The authors have no conflict of interest.
- Published
- 2022
- Full Text
- View/download PDF
14. Vmeasur: A software package for experimental and clinical measurement of mesenteric lymphatic contractile function over an extended vessel length.
- Author
-
Russell PS, Hucklesby JJW, Hong J, Cao E, Trevaskis NL, Angel CE, Windsor JA, and Phillips ARJ
- Subjects
- Humans, Muscle Contraction, Mesentery, Software, Contrast Media, Lymphatic Vessels diagnostic imaging
- Abstract
Objective: Conventionally, in vivo mesenteric lymphatic contractile function is measured using a high magnification transmission microscope (field of view 0.3-1.5 mm), which precludes visualization of extended lengths of vessels embedded in mesenteric fat. Existing software is not optimized for imaging at a low magnification using a contrast agent. We aimed to develop a simple and clinically transferable method for in situ visualization, image analysis, and quantitative assessment of mesenteric lymphatic contractile function over an extended area., Methods: Subserosal injection of various blue dyes was taken up by mesenteric lymphatics and visualized under a stereomicroscope (25×), allowing for video recording of 1.4 × 1.1 cm of intact mesentery. A new R package ("vmeasur") that combines multiple high-performance image analyses into a single workflow was developed. The edges of each vessel were determined by applying an automated threshold to each frame (with real-time manual verification). The vessel width at every point in each frame was plotted to provide contractile parameters over time and along the lymphatic vessel length., Results: Contractile parameters and their differences along the length of the vessel were accurately calculated in a rodent model. In a human mesenteric lymphatic, the algorithm was also able to measure changes in diameter over length., Conclusion: This software offers a low cost, rapid, and accessible method to measure lymphatic contractile function over a wide area, showing differences in contractility along the length of a vessel. Because the presence of mesenteric fat has less of an impact on imaging, due to the use of an exogenous contrast agent, there is potential for clinical application., (© 2022 The Authors. Microcirculation published by John Wiley & Sons Ltd.)
- Published
- 2022
- Full Text
- View/download PDF
15. Lymphatic contractile function: a comprehensive review of drug effects and potential clinical application.
- Author
-
Russell PS, Hong J, Trevaskis NL, Windsor JA, Martin ND, and Phillips ARJ
- Subjects
- Calcium Channel Blockers pharmacology, Muscle Contraction, Lymphatic System, Lymphatic Vessels
- Abstract
The lymphatic system and the cardiovascular (CV) system work together to maintain body fluid homeostasis. Despite that, the lymphatic system has been relatively neglected as a potential drug target and a source of adverse effects from CV drugs. Like the heart, the lymphatic vessels undergo phasic contractions to promote lymph flow against a pressure gradient. Dysfunction or failure of the lymphatic pump results in fluid imbalance and tissue oedema. While this can be due to drug effects, it is also a feature of breast cancer-associated lymphoedema, chronic venous insufficiency, congestive heart failure, and acute systemic inflammation. There are currently no specific drug treatments for lymphatic pump dysfunction in clinical use despite the wealth of data from pre-clinical studies. The aim of this study was to identify (i) drugs with direct effects on lymphatic tonic and phasic contractions with potential for clinical application, and (ii) drugs in current clinical use that have a positive or negative side effect on lymphatic function. We comprehensively reviewed all studies that tested the direct effect of a drug on the contractile function of lymphatic vessels. Of the 208 drugs identified from 193 studies, about a quarter had only stimulatory effects on lymphatic tone, contraction frequency, and/or contraction amplitude. Of Food and Drug Administration-approved drugs, there were 14 that increased lymphatic phasic contractile function. The most frequently used class of drugs with inhibitory effects on lymphatic pump function were the calcium channels blockers. This review highlights the opportunity for specific drug treatments of lymphatic dysfunction in various disease states and for avoiding adverse drug effects on lymphatic contractile function., Competing Interests: Conflict of interest: N.T. is an inventor of a lymph-directing glyceride prodrug technology, which enhances delivery of drugs to intestinal lymph. This technology has been patented and licensed via a commercial agreement with PureTech Health, Boston. PureTech Health has subsequently entered into a collaboration agreement with Boehringer Ingelheim to explore the technology in immune modulation. N.T. receives payments and royalties from PureTech Health as part of the agreement., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2022
- Full Text
- View/download PDF
16. Fluorescent Tracers for In Vivo Imaging of Lymphatic Targets.
- Author
-
Russell PS, Velivolu R, Maldonado Zimbrón VE, Hong J, Kavianinia I, Hickey AJR, Windsor JA, and Phillips ARJ
- Abstract
The lymphatic system continues to gain importance in a range of conditions, and therefore, imaging of lymphatic vessels is becoming more widespread for research, diagnosis, and treatment. Fluorescent lymphatic imaging offers advantages over other methods in that it is affordable, has higher resolution, and does not require radiation exposure. However, because the lymphatic system is a one-way drainage system, the successful delivery of fluorescent tracers to lymphatic vessels represents a unique challenge. Each fluorescent tracer used for lymphatic imaging has distinct characteristics, including size, shape, charge, weight, conjugates, excitation/emission wavelength, stability, and quantum yield. These characteristics in combination with the properties of the target tissue affect the uptake of the dye into lymphatic vessels and the fluorescence quality. Here, we review the characteristics of visible wavelength and near-infrared fluorescent tracers used for in vivo lymphatic imaging and describe the various techniques used to specifically target them to lymphatic vessels for high-quality lymphatic imaging in both clinical and pre-clinical applications. We also discuss potential areas of future research to improve the lymphatic fluorescent tracer design., 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. The handling editor SH declared a past co-authorship with authors JH, AP, JW., (Copyright © 2022 Russell, Velivolu, Maldonado Zimbrón, Hong, Kavianinia, Hickey, Windsor and Phillips.)
- Published
- 2022
- Full Text
- View/download PDF
17. Bio-Mimicking Acellular Wet Electrospun Scaffolds Promote Accelerated Integration and Re-Epithelialization of Full-Thickness Dermal Wounds.
- Author
-
Chin JS, Madden LE, Phillips ARJ, Chew SY, and Becker DL
- Abstract
Scaffolds can promote the healing of burns and chronic skin wounds but to date have suffered from issues with achieving full skin integration. Here, we characterise the wound response by both tissue integration and re-epithelialization to a scaffold using wet electrospinning to fabricate 3D fibrous structures. Two scaffold materials were investigated: poly(ε-caprolactone) (PCL) and PCL + 20% rat tail type 1 collagen (PCL/Coll). We assessed re-epithelisation, inflammatory responses, angiogenesis and the formation of new extracellular matrix (ECM) within the scaffolds in rat acute wounds. The 3D PCL/Coll scaffolds impeded wound re-epithelisation, inducing a thickening of wound-edge epidermis as opposed to a thin tongue of migratory keratinocytes as seen when 3D PCL scaffolds were implanted in the wounds. A significant inflammatory response was observed with 3D PCL/Coll scaffolds but not with 3D PCL scaffolds. Enhanced fibroblast migration and angiogenesis into 3D PCL scaffolds was observed with a significant deposition of new ECM. We observed that this deposition of new ECM within the scaffold was key to enabling re-epithelialization over the scaffold. Such scaffolds provide a biocompatible environment for cell integration to lay down new ECM and encourage re-epithelisation over the implanted scaffold.
- Published
- 2022
- Full Text
- View/download PDF
18. Sampling Thoracic Duct Lymph After Esophagectomy: A Pilot Study Investigating the "Gut-Lymph" Concept.
- Author
-
Escott ABJ, Hong J, Connor BN, Phang KL, Holden AH, Phillips ARJ, and Windsor JA
- Subjects
- Animals, Cytokines, Humans, Ischemia surgery, Pilot Projects, Esophagectomy methods, Thoracic Duct physiology, Thoracic Duct surgery
- Abstract
Background: Gut-lymph in animal models of acute disease is altered by intestinal ischemia and contributes to the development of systemic inflammation and organ dysfunction. Investigating gut-lymph in humans is hampered difficulty in accessing the thoracic duct (TD) for lymph sampling. The aims of this study were to develop and pilot a technique of intraoperative TD cannulation with delayed embolization to serially measure TD lymph pressure, flow, and composition (including markers of intestinal injury) during the early postoperative period and in response to enteral feeding and vasopressor treatment. Methods: A Seldinger technique was used for percutaneous TD cannulation during an Ivor Lewis esophagogastrectomy. Lymph flow rate and pressure were measured. TD lymph and plasma were sampled at 12 hourly intervals for up to 120 hours after surgery and before TD embolization. Biochemistry, lipids, cytokines, and markers of intestinal injury were measured before and after enteral feeding commenced at 36 hours. Results: Intraoperative TD cannulation was technically feasible in three of four patients. Delayed TD embolization was only successful in one of three patients, with two patients requiring a re-thoracotomy to treat chylothorax. Profound changes in TD composition, but not flow rate, occurred over time and in response to enteral feeding and vasopressors. TD lymph compared with plasma had significantly higher lipase (1.4-17 × ), interleukin-6 (8-108 × ), tumor necrosis factor-α (2.7-17 × ), d-lactate (0.3-23 × ), endotoxin (0.1-41 × ), and intestinal fatty acid binding protein (1.1-853 × ). Conclusions: Although TD cannulation and lymph sampling were successful, TD embolization failed in two of three patients. The composition of sampled TD lymph changed dramatically in response to enteral feeding, indicating intestinal ischemia that could be exacerbated by nonselective vasopressors. The higher concentration of proinflammatory cytokines and gut injury markers in TD lymph, compared with plasma, lends support to the gut-lymph concept.
- Published
- 2022
- Full Text
- View/download PDF
19. The effect of respiration and body position on terminal thoracic duct diameter and the lymphovenous junction: An exploratory ultrasound study.
- Author
-
Hinton LR, O'Hagan LA, Griffiths AP, Clark AR, Phillips ARJ, Windsor JA, and Mirjalili SA
- Subjects
- Humans, Supine Position, Ultrasonography, Respiration, Thoracic Duct diagnostic imaging
- Abstract
The thoracic duct (TD) drains most of the body's lymph back to the venous system via its lymphovenous junction (LVJ), playing a pivotal role in fluid homeostasis, fat absorption and the systemic immune response. The respiratory cycle is thought to assist with lymph flow, but the precise mechanism underpinning terminal TD lymph flow into the central veins is not well understood. The aim of this study was to use ultrasonography (US) to explore the relationship between terminal TD lymph flow, the respiratory cycle, and gravity. The left supraclavicular fossa was scanned in healthy non-fasted volunteers using high-resolution (13-5 MHz) US to identify the terminal TD and the presence of a lymphovenous valve (LVV). The TD's internal diameter was measured in relation to respiration (inspiration vs. expiration) and body positioning (supine vs. Trendelenburg). The terminal TD was visualized in 20/33 (61%) healthy volunteers. An LVV was visualized in only 4/20 (20%) cases. The mean terminal TD diameter in the supine position was 1.7 mm (range 0.8-3.1 mm); this increased in full inspiration (mean 1.8 mm, range 0.9-3.2 mm, p < 0.05), and in the Trendelenburg position (mean 1.8 mm, range 1.2-3.1 mm, p < 0.05). The smallest mean terminal TD diameter occurred in full expiration (1.6 mm, range 0.7-3.1 mm, p < 0.05). Respiration and gravity impact the terminal TD diameter. Due to the challenges of visualizing the TD and LVJ, other techniques such as dynamic magnetic resonance imaging will be required to fully understand the factors governing TD lymph flow., (© 2021 American Association of Clinical Anatomists.)
- Published
- 2022
- Full Text
- View/download PDF
20. Electrochemical Methods for the Analysis of Milk.
- Author
-
Motshakeri M, Sharma M, Phillips ARJ, and Kilmartin PA
- Subjects
- Allergens analysis, Animals, Nitrites analysis, Electrochemical Techniques, Milk chemistry
- Abstract
The milk and dairy industries are some of the most profitable sectors in many countries. This business requires close control of product quality and continuous testing to ensure the safety of the consumers. The potential risk of contaminants or degradation products and undesirable chemicals necessitates the use of fast, reliable detection tools to make immediate production decisions. This review covers studies on the application of electrochemical methods to milk (i.e., voltammetric and amperometric) to quantify different analytes, as reported over the last 10 to 15 years. The review covers a wide range of analytes, including allergens, antioxidants, organic compounds, nitrogen- and aldehyde containing compounds, biochemicals, heavy metals, hydrogen peroxide, nitrite, and endocrine disruptors. The review also examines pretreatment procedures applied to milk samples and the use of novel sensor materials. Final perspectives are provided on the future of cost-effective and easy-to-use electrochemical sensors and their advantages over conventional methods.
- Published
- 2022
- Full Text
- View/download PDF
21. Extracellular matrix and cellular senescence in venous leg ulcers.
- Author
-
Lim DXE, Richards T, Kanapathy M, Sudhaharan T, Wright GD, Phillips ARJ, and Becker DL
- Subjects
- Aged, Aged, 80 and over, Case-Control Studies, Cohort Studies, Diabetic Foot metabolism, Female, Follow-Up Studies, Humans, Male, Middle Aged, Prognosis, Varicose Ulcer metabolism, Cellular Senescence, Collagen metabolism, Diabetic Foot pathology, Extracellular Matrix metabolism, Pressure Ulcer pathology, Varicose Ulcer pathology, Wound Healing
- Abstract
High prevalence of non-healing chronic wounds contributes to a huge healthcare burden across the world. Early treatment interventions for non-healing wounds are vital. It was previously shown that accumulation of 15% or more of senescent cells in a chronic wound edge is an indicator that the wound is unlikely to heal. However, determining the presence of senescent cells would require invasive procedures such as tissue biopsies to be taken. In this study, we found a strong correlation between decreased collagen area and presence of senescent cells in human chronic wounds i.e. venous leg ulcer (VLU), diabetic foot ulcer (DFU) and pressure ulcer (PRU). We also report that the lowest collagen levels were found in VLU patients less than 60 years of age, with a persistent wound of > 24 months. Elevated levels of senescent cells were also found in VLU of males. Second harmonic imaging of collagen at the edge of chronic wounds with a handheld multiphoton device could be used to predict the number of senescent cells, indicating if the wound is on a healing trajectory or not. Our data support the use of collagen imaging in cutaneous wound assessment for a faster and non-invasive method to predict cellular senescence and determining wound trajectory of healing., (© 2021. The Author(s).)
- Published
- 2021
- Full Text
- View/download PDF
22. Mesenteric lymphatic dysfunction promotes insulin resistance and represents a potential treatment target in obesity.
- Author
-
Cao E, Watt MJ, Nowell CJ, Quach T, Simpson JS, De Melo Ferreira V, Agarwal S, Chu H, Srivastava A, Anderson D, Gracia G, Lam A, Segal G, Hong J, Hu L, Phang KL, Escott ABJ, Windsor JA, Phillips ARJ, Creek DJ, Harvey NL, Porter CJH, and Trevaskis NL
- Subjects
- Adult, Aged, Animals, Cyclooxygenase 2 metabolism, Female, Humans, Intra-Abdominal Fat metabolism, Male, Mice, Mice, Inbred C57BL, Middle Aged, Obesity, Abdominal therapy, Rats, Rats, Sprague-Dawley, Signal Transduction, Vascular Endothelial Growth Factor C metabolism, Insulin Resistance, Lymphatic Vessels physiopathology, Mesentery physiopathology, Obesity, Abdominal physiopathology
- Abstract
Visceral adipose tissue (VAT) encases mesenteric lymphatic vessels and lymph nodes through which lymph is transported from the intestine and mesentery. Whether mesenteric lymphatics contribute to adipose tissue inflammation and metabolism and insulin resistance is unclear. Here we show that obesity is associated with profound and progressive dysfunction of the mesenteric lymphatic system in mice and humans. We find that lymph from mice and humans consuming a high-fat diet (HFD) stimulates lymphatic vessel growth, leading to the formation of highly branched mesenteric lymphatic vessels that 'leak' HFD-lymph into VAT and, thereby, promote insulin resistance. Mesenteric lymphatic dysfunction is regulated by cyclooxygenase (COX)-2 and vascular endothelial growth factor (VEGF)-C-VEGF receptor (R)3 signalling. Lymph-targeted inhibition of COX-2 using a glyceride prodrug approach reverses mesenteric lymphatic dysfunction, visceral obesity and inflammation and restores glycaemic control in mice. Targeting obesity-associated mesenteric lymphatic dysfunction thus represents a potential therapeutic option to treat metabolic disease., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)
- Published
- 2021
- Full Text
- View/download PDF
23. The effects of Staphylococcus aureus biofilm conditioned media on 3T3 fibroblasts.
- Author
-
Madden L, Low SH, Phillips ARJ, Kline KA, and Becker DL
- Abstract
Staphylococcus aureus (SA) is the most common bacterial species in chronic wounds. However, there is a lack of understanding of how SA secretions affect the cell biology during the healing process. We studied the effects of biofilm-secretions from SA strain SA29213 on 3T3 fibroblasts. SA29213 is a chronic wound isolate and widely used as a reference strain. We used a series of concentrations of biofilm-conditioned media (BCM) and found 100% BCM is lethal within 10 h. Cells survived in ≤75% BCM but the rate of closure in scratch wound assays was reduced. Treatment with 75% and 50% BCM caused fibroblasts to change shape and develop dendrite like processes. Prolonged treatment with 75% and 50% BCM reduced cell proliferation and increased the 4n deoxyribonucleic acid cell population with cell cycle arrest. There was also an elevation in the senescence marker beta galactosidase and the number of multinucleated cells. Shorter treatments with 75% and 50% SA BCM caused an increase in cell-cell adhesion and a redistribution of β-catenin from the cell membrane to the cytoplasm along with a change in the appearance and decrease in size of ZO-1, vinculin and paxillin structures. Fibroblasts in the edge of chronic wounds exposed to the secretions of SA may suffer similar effects such as induction of senescence, reduced proliferation and migration, which may contribute to the delayed healing of these chronic infected wounds., Competing Interests: None declared., (© The Author(s) 2021. Published by Oxford University Press on behalf of FEMS.)
- Published
- 2021
- Full Text
- View/download PDF
24. Electrochemical Preparation of Poly(3,4-Ethylenedioxythiophene) Layers on Gold Microelectrodes for Uric Acid-Sensing Applications.
- Author
-
Motshakeri M, Phillips ARJ, and Kilmartin PA
- Subjects
- Bridged Bicyclo Compounds, Heterocyclic, Microelectrodes, Polymers, Gold, Uric Acid
- Abstract
Two different methods for the synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) on gold electrodes are described, using electropolymerization of 3,4-ethylenedioxythiophene (EDOT) monomer in an aqueous and an organic solution. Cyclic voltammetry (CV) was used in the synthesis of PEDOT thin layers. Lithium perchlorate (LiClO4) was used as a dopant in both aqueous (aqueous/acetonitrile (ACN)) and organic (propylene carbonate (PC)) solvent systems. After the PEDOT layer was created in the organic system, the electrode surface was acclimatized by successive cycling in an aqueous solution for use as a sensor for aqueous samples. The use of an aqueous-based electropolymerization method has the potential benefit of removing the acclimatization step to have a shorter sensor preparation time. Although the aqueous method is more economical and environmentally friendly than the organic solvent method, superior PEDOT formation is obtained in the organic solution. The resulting PEDOT electrode surfaces were characterized by scanning electron microscopy (SEM), which showed the constant growth of PEDOT during electropolymerization from the organic PC solution, with rapid fractal-type growth on gold (Au) microelectrodes.
- Published
- 2021
- Full Text
- View/download PDF
25. Conservative fluid resuscitation and aggressive enteral nutrition: A potentially lethal combination in patients with critical illness.
- Author
-
Asrani VM, McArthur C, Phillips ARJ, Bissett I, and Windsor JA
- Subjects
- Critical Care, Fluid Therapy, Humans, Critical Illness, Enteral Nutrition
- Published
- 2021
- Full Text
- View/download PDF
26. The Lymphovenous Junction of the Thoracic Duct: A Systematic Review of its Structural and Functional Anatomy.
- Author
-
O'Hagan LA, Windsor JA, Itkin M, Russell PS, Phillips ARJ, and Mirjalili SA
- Subjects
- Animals, Humans, Lymphatic System, Lymphatic Diseases, Thoracic Duct
- Abstract
Background: The lymphovenous junction (LVJ) of the thoracic duct (TD) is the principle outlet of the lymphatic system. Interest in this junction is growing as its role in lymphatic outflow obstruction is being realized, and as minimally invasive procedures for accessing the terminal TD become more common. Despite the growing clinical significance of the LVJ, its precise form and function remain unclear. The aim of this article was to systematically review the literature surrounding the structure and function of the LVJ and its associated lymphovenous valve (LVV). Methods and Results: A systematic review of the structure and function of the LVJ and LVV was undertaken using the MEDLINE, Scopus, and Google Scholar databases. Human and animal studies up to November 2019, with no language or past date restriction, were included. Forty-six relevant articles were reviewed. The LVJ shows marked anatomical variation. A valve is frequently absent at the LVJ, but when present it displays numerous distinct morphologies. These include bicuspid semilunar, ostial, and flap-like structure. Other factors, such as functional platelet plugs, or the tangential/intramural course of the terminal TD across the vein wall, may work to prevent blood from entering the lymphatic system. Conclusions: The form and function of the LVJ remain unclear. Dedicated studies of this area in vivo are required to elucidate how this part of the body functions in both health and disease.
- Published
- 2021
- Full Text
- View/download PDF
27. Methods for studying pulmonary lymphatics.
- Author
-
Maldonado-Zimbron VE, Hong J, Russell P, Trevaskis NL, Windsor JA, and Phillips ARJ
- Subjects
- Humans, Lung, Lymphatic Vessels
- Abstract
Competing Interests: Conflict of interest: V.E. Maldonado-Zimbron has nothing to disclose. Conflict of interest: J. Hong reports personal fees from Hugo Charitable Trust, during the conduct of the study. Conflict of interest: P. Russell has nothing to disclose. Conflict of interest: N.L. Trevaskis reports research support from Puretech Health, outside the submitted work; and has a patent “Lymph directing prodrugs” licensed to Puretech Health and Boehringer Ingelheim. Conflict of interest: J.A. Windsor will report to Health Research Council (NZ) on grants received. Conflict of interest: A.R.J. Phillips reports grants from Health Research Council (NZ), during the conduct of the study.
- Published
- 2021
- Full Text
- View/download PDF
28. Intestinal delivery in a long-chain fatty acid formulation enables lymphatic transport and systemic exposure of orlistat.
- Author
-
Lee G, Han S, Lu Z, Hong J, Phillips ARJ, Windsor JA, Porter CJH, and Trevaskis NL
- Subjects
- Biological Availability, Intestinal Absorption, Orlistat, Fatty Acids, Lymph
- Abstract
Orlistat is a pancreatic lipase (PL) inhibitor that inhibits dietary lipid absorption and is used to treat obesity. The oral bioavailability of orlistat is considered zero after administration in standard formulations. This is advantageous in the treatment of obesity. However, if orlistat absorption could be improved it has the potential to treat diseases such as acute and critical illnesses where PL transport to the systemic circulation via gut lymph promotes organ failure. Orlistat is highly lipophilic and may associate with intestinal lipid absorption pathways into lymph. Here we investigate the potential to improve orlistat lymph and systemic uptake through intestinal administration in lipid formulations (LFs). The effect of lipid type, lipid dose, orlistat dose, and infusion time on lymph and systemic availability of orlistat was investigated. After administration in all LFs, orlistat concentrations in lymph were greater than in plasma, suggesting direct transport via lymph. Lymph and plasma orlistat derivative concentrations were ~8-fold greater after administration in a long-chain fatty acid (LC-FA) compared to a lipid-free, LC triglyceride (LC-TG) or medium-chain FA (MC-FA) formulation. Overall, administration of orlistat in a LC-FA formulation promotes lymph and systemic uptake which may enable treatment of diseases associated with elevated systemic PL activity., (Copyright © 2021. Published by Elsevier B.V.)
- Published
- 2021
- Full Text
- View/download PDF
29. Anatomy of the lymphovenous valve of the thoracic duct in humans.
- Author
-
O'Hagan LA, Windsor JA, Phillips ARJ, Itkin M, Russell PS, and Mirjalili SA
- Subjects
- Aged, Aged, 80 and over, Cadaver, Female, Humans, Lymphatic System diagnostic imaging, Lymphatic Vessels diagnostic imaging, Male, Middle Aged, Thoracic Duct diagnostic imaging, X-Ray Microtomography, Lymphatic System anatomy & histology, Lymphatic Vessels anatomy & histology, Thoracic Duct anatomy & histology
- Abstract
The majority of lymph generated in the body is returned to the blood circulation via the lymphovenous junction (LVJ) of the thoracic duct (TD). A lymphovenous valve (LVV) is thought to guard this junction by regulating the flow of lymph to the veins and preventing blood from entering the lymphatic system. Despite these important functions, the morphology and mechanism of this valve remains unclear. The aim of this study was to investigate the anatomy of the LVV of the TD. To do this, the TD and the great veins of the left side of the neck were harvested from 16 human cadavers. The LVJs from 12 cadavers were successfully identified and examined macroscopically, microscopically, and using microcomputed tomography. In many specimens, the TD branched before entering the veins. Thus, from 12 cadavers, 21 LVJs were examined. Valves were present at 71% of LVJs (15/21) and were absent in the remainder. The LVV, when present, was typically a bicuspid semilunar valve, although the relative size and position of its cusps were variable. Microscopically, the valve cusps comprised luminal extensions of endothelium with a thin core of collagenous extracellular matrix. This study clearly demonstrated the morphology of the human LVV. This valve may prevent blood from entering the lymphatic system, but its variability and frequent absence calls into question its utility. Further structural and functional studies are required to better define the role of the LVV in health and disease., (© 2020 Anatomical Society.)
- Published
- 2020
- Full Text
- View/download PDF
30. Intestinal Lymph Flow, and Lipid and Drug Transport Scale Allometrically From Pre-clinical Species to Humans.
- Author
-
Trevaskis NL, Lee G, Escott A, Phang KL, Hong J, Cao E, Katneni K, Charman SA, Han S, Charman WN, Phillips ARJ, Windsor JA, and Porter CJH
- Abstract
The intestinal lymphatic system transports fluid, immune cells, dietary lipids, and highly lipophilic drugs from the intestine to the systemic circulation. These transport functions are important to health and when dysregulated contribute to pathology. This has generated significant interest in approaches to deliver drugs to the lymphatics. Most of the current understanding of intestinal lymph flow, and lymphatic lipid and drug transport rates, comes from in vitro studies and in vivo animal studies. In contrast, intestinal lymphatic transport studies in human subjects have been limited. Recently, three surgical patients had cannulation of the thoracic lymph duct for collection of lymph before and during a stepwise increase in enteral feed rate. We compared these data to studies where we previously enterally administered controlled quantities of lipid and the lipophilic drug halofantrine to mice, rats and dogs and collected lymph and blood (plasma). The collected lymph was analyzed to compare lymph flow rate, triglyceride (TG) and drug transport rates, and plasma was analyzed for drug concentrations, as a function of enteral lipid dose across species. Lymph flow rate, TG and drug transport increased with lipid administration in all species tested, and scaled allometrically according to the equation A = a M
E where A is the lymph transport parameter, M is animal body mass, a is constant and E is the allometric exponent. For lymph flow rate and TG transport, the allometric exponents were 0.84-0.94 and 0.80-0.96, respectively. Accordingly, weight normalized lymph flow and TG mass transport were generally lower in larger compared to smaller species. In comparison, mass transport of drug via lymph increased in a greater than proportional manner with species body mass with an exponent of ∼1.3. The supra-proportional increase in lymphatic drug transport with species body mass appeared to be due to increased partitioning of drug into lymph rather than blood following absorption. Overall, this study proposes that intestinal lymphatic flow, and lymphatic lipid and drug transport in humans is most similar to species with higher body mass such as dogs and underestimated by studies in rodents. Notably, lymph flow and lipid transport in humans can be predicted from animal data via allometric scaling suggesting the potential for similar relationships with drug transport., (Copyright © 2020 Trevaskis, Lee, Escott, Phang, Hong, Cao, Katneni, Charman, Han, Charman, Phillips, Windsor and Porter.)- Published
- 2020
- Full Text
- View/download PDF
31. High-resolution 3D imaging and topological mapping of the lymph node conduit system.
- Author
-
Kelch ID, Bogle G, Sands GB, Phillips ARJ, LeGrice IJ, and Dunbar PR
- Subjects
- Animals, B-Lymphocytes immunology, Cell Movement, Fibroblasts, Mice immunology, T-Lymphocytes immunology, Image Processing, Computer-Assisted methods, Imaging, Three-Dimensional methods, Lymph Nodes diagnostic imaging
- Abstract
The conduit network is a hallmark of lymph node microanatomy, but lack of suitable imaging technology has prevented comprehensive investigation of its topology. We employed an extended-volume imaging system to capture the conduit network of an entire murine lymph node (comprising over 280,000 segments). The extensive 3D images provide a comprehensive overview of the regions supplied by conduits, including perivascular sleeves and distinctive "follicular reservoirs" within B cell follicles, surrounding follicular dendritic cells. A 3D topology map of conduits within the T-cell zone showed homogeneous branching, but conduit density was significantly higher in the superficial T-cell zone compared with the deep zone, where distances between segments are sufficient for T cells to lose contact with fibroblastic reticular cells. This topological mapping of the conduit anatomy can now aid modeling of its roles in lymph node function, as we demonstrate by simulating T-cell motility in the different T-cell zones., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
- Full Text
- View/download PDF
32. Lymphatic Uptake of Liposomes after Intraperitoneal Administration Primarily Occurs via the Diaphragmatic Lymphatics and is Dependent on Liposome Surface Properties.
- Author
-
Lee G, Han S, Inocencio I, Cao E, Hong J, Phillips ARJ, Windsor JA, Porter CJH, and Trevaskis NL
- Subjects
- 1,2-Dipalmitoylphosphatidylcholine chemistry, Animals, Drug Delivery Systems, Injections, Intraperitoneal, Male, Rats, Sucrose chemistry, Liposomes chemistry, Lymph Nodes metabolism, Peritoneum metabolism
- Abstract
Drugs are commonly administered via the intraperitoneal (IP) route to treat localized infections and cancers in patients and to test drug efficacy and toxicity in preclinical studies. Despite this, there remain large gaps in our understanding of drug absorption routes (lymph vs blood) and pharmacokinetics following IP administration. This is particularly true when drugs are administered in complex delivery systems such as liposomes which are the main marketed formulation for several drugs that are administered intraperitoneally. This study investigated the impact of liposome surface properties (charge and PEGylation) on absorption into lymph and blood, and lymphatic disposition patterns, following IP administration. To achieve this, stable
3 H-dipalmitoyl-phosphatidylcholine (DPPC) and14 C-sucrose-radiolabeled liposomes of 100-150 nm diameter with negative, neutral, or positive surface charge, or a PEGylated surface, were prepared and administered intraperitoneally to rats. Radiolabel concentrations were measured in lymph, blood, and lymph nodes (LNs). Lymph was collected from the thoracic lymph duct at either the abdomen (ABD) or the jugular-subclavian junction (JSJ). The lymphatic recovery of the radiolabels was substantially lower after administration in positively charged compared to the neutral, negative, or PEGylated liposomes. Radiolabel recovery was substantially greater (up to 18-fold) in the thoracic lymph collected at the JSJ when compared to that at the ABD, suggesting that liposomes entered the lymphatics at the diaphragm. Consistent with this, the concentration of the liposome labels was substantially higher (up to seven-fold) in mediastinal than in mesenteric LNs. Overall, this study shows how the peritoneal absorption and lymphatic disposition of drugs administered intraperitoneally can be manipulated through a careful selection of the drug delivery system and may thus be optimized to treat localized conditions such as cancers, infections, inflammatory diseases, and acute and critical illness.- Published
- 2019
- Full Text
- View/download PDF
33. Application of cyclic voltammetry to analyse uric acid and reducing agents in commercial milks.
- Author
-
Motshakeri M, Phillips ARJ, and Kilmartin PA
- Subjects
- Animals, Antioxidants chemistry, Ascorbate Oxidase metabolism, Chromatography, High Pressure Liquid, Electrodes, Hydrogen-Ion Concentration, Temperature, Urate Oxidase metabolism, Electrochemical Techniques, Milk chemistry, Reducing Agents analysis, Uric Acid analysis
- Abstract
Cyclic voltammetry (CV) and high performance liquid chromatography (HPLC), were compared to quantify uric acid and antioxidant reducing agents in 36 milk samples. The enzymes uricase and ascorbate oxidase were used to remove uric and ascorbic acids and showed that the peaks obtained by CV and HPLC did not contain contributions from other unknown compounds. The levels of uric acid obtained by CV compared well to those determined using HPLC, with only a few exceptions, and the average difference was around 6%. CV measurements were made using the main anodic peak seen at approximately 330 mV (Ag/AgCl), while a later oxidation peak at approximately 650 mV can be associated with further reducing agents present in milk. The electrochemical method was quicker to apply than HPLC that included a pre-treatment step, and provides an inexpensive and simple method for the reliable analysis of uric acid in milk., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
34. Therapeutic delivery to the peritoneal lymphatics: Current understanding, potential treatment benefits and future prospects.
- Author
-
Sarfarazi A, Lee G, Mirjalili SA, Phillips ARJ, Windsor JA, and Trevaskis NL
- Subjects
- Animals, Biological Transport, Drug Delivery Systems, Humans, Injections, Intraperitoneal, Pharmaceutical Preparations administration & dosage, Lymphatic Vessels metabolism, Peritoneum metabolism
- Abstract
The interest in approaches to deliver therapeutics to the lymphatic system has increased in recent years as the lymphatics have been discovered to play an important role in a range of disease states such as cancer metastases, inflammatory and metabolic disease, and acute and critical illness. Therapeutic delivery to lymph has the potential to enhance treatment of these conditions. Currently much of the existing data explores therapeutic delivery to the lymphatic vessels and nodes that drain peripheral tissues and the intestine. Relatively little focus has been given to understanding the anatomy, function and therapeutic delivery to the peritoneal lymphatics. Gaining a better understanding of peritoneal lymphatic structure and function would contribute to the understanding of disease processes involving these lymphatics and facilitate the development of delivery systems to target therapeutics to the peritoneal lymphatics. This review explores the basic anatomy and ultrastructure of the peritoneal lymphatics system, the lymphatic drainage pathways from the peritoneum, and therapeutic and delivery system characteristics (size, lipophilicity and surface properties) that favour lymph uptake and retention after intraperitoneal delivery. Finally, techniques that can be used to quantify uptake into peritoneal lymph are outlined, providing a platform for future studies., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
35. Renal Lymphatics: Anatomy, Physiology, and Clinical Implications.
- Author
-
Russell PS, Hong J, Windsor JA, Itkin M, and Phillips ARJ
- Abstract
Renal lymphatics are abundant in the cortex of the normal kidney but have been largely neglected in discussions around renal diseases. They originate in the substance of the renal lobule as blind-ended initial capillaries, and can either follow the main arteries and veins toward the hilum, or penetrate the capsule to join capsular lymphatics. There are no valves present in interlobular lymphatics, which allows lymph formed in the cortex to exit the kidney in either direction. There are very few lymphatics present in the medulla. Lymph is formed from interstitial fluid in the cortex, and is largely composed of capillary filtrate, but also contains fluid reabsorbed from the tubules. The two main factors that contribute to renal lymph formation are interstitial fluid volume and intra-renal venous pressure. Renal lymphatic dysfunction, defined as a failure of renal lymphatics to adequately drain interstitial fluid, can occur by several mechanisms. Renal lymphatic inflow may be overwhelmed in the setting of raised venous pressure (e.g., cardiac failure) or increased capillary permeability (e.g., systemic inflammatory response syndrome). Similarly, renal lymphatic outflow, at the level of the terminal thoracic duct, may be impaired by raised central venous pressures. Renal lymphatic dysfunction, from any cause, results in renal interstitial edema. Beyond a certain point of edema, intra-renal collecting lymphatics may collapse, further impairing lymphatic drainage. Additionally, in an edematous, tense kidney, lymphatic vessels exiting the kidney via the capsule may become blocked at the exit point. The reciprocal negative influences between renal lymphatic dysfunction and renal interstitial edema are expected to decrease renal function due to pressure changes within the encapsulated kidney, and this mechanism may be important in several common renal conditions.
- Published
- 2019
- Full Text
- View/download PDF
36. Detection of Neurotransmitters by Three-Dimensional Laser-Scribed Graphene Grass Electrodes.
- Author
-
Xu G, Jarjes ZA, Wang HW, Phillips ARJ, Kilmartin PA, and Travas-Sejdic J
- Subjects
- Electrodes, Female, Humans, Nanostructures chemistry, Oxidation-Reduction, Dopamine urine, Electrochemical Techniques methods, Epinephrine urine, Graphite chemistry, Neurotransmitter Agents urine, Norepinephrine urine
- Abstract
Carbon nanomaterials possess superb properties and have contributed considerably to the advancement of integrated point-of-care chemical and biological sensing devices. Graphene has been widely researched as a signal transducing and sensing material. Here, a grass-like laser-scribed graphene (LSG) was synthesized by direct laser induction on common polyimide plastics. The resulting LSG grass was employed as a disposable electrochemical sensor for the detection of three neurotransmitters, dopamine (DA), epinephrine (EP), and norepinephrine (NE), and in the presence of uric acid and ascorbic acid as potential interferants, using differential pulse voltammetry and cyclic voltammetry. The LSG grass sensor achieved sensitivities of 0.243, 0.067, and 0.110 μA μM
-1 for DA, EP, and NE, respectively, whereas the limits of detection were 0.43, 1.1, and 1.3 μM, respectively. The selectivity of LSG grass was excellent for competing biomarkers with high structural similarity (EP vs NE and EP vs DA). The exceptional performance of LSG grass for DA, EP, and NE detection holds a promising future for carbon nanomaterial sensors with unique surface morphologies.- Published
- 2018
- Full Text
- View/download PDF
37. The anatomy and physiology of the terminal thoracic duct and ostial valve in health and disease: potential implications for intervention.
- Author
-
Ratnayake CBB, Escott ABJ, Phillips ARJ, and Windsor JA
- Subjects
- Animals, Heart Failure pathology, Heart Failure physiopathology, Humans, Jugular Veins anatomy & histology, Jugular Veins physiology, Liver Cirrhosis pathology, Liver Cirrhosis physiopathology, Saphenous Vein anatomy & histology, Saphenous Vein physiology, Thoracic Duct anatomy & histology, Thoracic Duct physiology
- Abstract
The thoracic duct (TD) transports lymph drained from the body to the venous system in the neck via the lymphovenous junction. There has been increased interest in the TD lymph (including gut lymph) because of its putative role in the promotion of systemic inflammation and organ dysfunction during acute and critical illness. Minimally invasive TD cannulation has recently been described as a potential method to access TD lymph for investigation. However, marked anatomical variability exists in the terminal segment and the physiology regarding the ostial valve and terminal TD is poorly understood. A systematic review was conducted using three databases from 1909 until May 2017. Human and animal studies were included and data from surgical, radiological and cadaveric studies were retrieved. Sixty-three articles from the last 108 years were included in the analysis. The terminal TD exists as a single duct in its terminal course in 72% of cases and 13% have multiple terminations: double (8.5%), triple (1.8%) and quadruple (2.2%). The ostial valve functions to regulate flow in relation to the respiratory cycle. The patency of this valve found at the lymphovenous junction opening, is determined by venous wall tension. During inspiration, central venous pressure (CVP) falls and the valve cusps collapse to allow antegrade flow of lymph into the vein. During early expiration when CVP and venous wall tension rises, the ostial valve leaflets cover the opening of the lymphovenous junction preventing antegrade lymph flow. During chronic disease states associated with an elevated mean CVP (e.g. in heart failure or cirrhosis), there is a limitation of flow across the lymphovenous junction. Although lymph production is increased in both heart failure and cirrhosis, TD lymph outflow across the lymphovenous junction is unable to compensate for this increase. In conclusion the terminal TD shows marked anatomical variability and TD lymph flow is controlled at the ostial valve, which responds to changes in CVP. This information is relevant to techniques for cannulating the TD, with the aid of minimally invasive methods and high resolution ultrasonography, to enable longitudinal physiology and lymph composition studies in awake patients with both acute and chronic disease., (© 2018 Anatomical Society.)
- Published
- 2018
- Full Text
- View/download PDF
38. Acute pancreatitis conditioned mesenteric lymph causes cardiac dysfunction in rats independent of hypotension.
- Author
-
Shanbhag ST, Choong B, Petrov M, Delahunt B, Windsor JA, and Phillips ARJ
- Subjects
- Animals, Hypotension, In Vitro Techniques, Male, Multiple Organ Failure etiology, Rats, Wistar, Heart Diseases etiology, Lymph, Pancreatitis complications
- Abstract
Background: Critical illness including severe acute pancreatitis is associated with the multiple organ dysfunction syndrome. The "gut-lymph" hypothesis states that multiple organ dysfunction syndrome is due to release of toxic factors from the intestine into the mesenteric lymph. The aims of this study were to determine the effect of normotensive acute pancreatitis conditioned mesenteric lymph on cardiac function and whether external drainage of mesenteric lymph would protect the heart., Methods: Groups of normal rats and those with normotensive taurocholate induced acute pancreatitis, had either no lymphatic intervention or thoracic duct ligation and external drainage of mesenteric lymph. After 6 hours, the hearts were removed for ex vivo functional measurements, including cardiac output, ventricular contractility (+dP/dt), and relaxation (-dP/dt). In a second experiment, mesenteric lymph from normal rats and those with established acute pancreatitis was infused into ex vivo perfused normal working rat hearts to assess impact on cardiac function. Heart and lung tissues were collected for assessment of edema., Results: Significant cardiac dysfunction, denoted by decreased cardiac output (21%), contractility (37%), relaxability (23%), and increased cardiac tissue edema (2-fold), developed in rats with established acute pancreatitis and no lymphatic intervention compared with the control group (all P < .05). Strikingly this cardiac dysfunction and edema was normalized in acute pancreatitis rats that had undergone prior thoracic duct ligation and external drainage of mesenteric lymph. In the second experiment, infusion of acute pancreatitis conditioned mesenteric lymph resulted in an immediate and significant similar magnitude decrease in of cardiac output (17%), contractility (22%), and relaxation (27%) compared with the infusion of normal lymph (all P <.05)., Conclusion: Mesenteric lymph from normotensive acute pancreatitis animals caused significant cardiac dysfunction which could be prevented by thoracic duct ligation and external drainage of mesenteric lymph., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
39. Changes in the extracellular matrix surrounding human chronic wounds revealed by 2-photon imaging.
- Author
-
Sutcliffe JES, Thrasivoulou C, Serena TE, Madden L, Richards T, Phillips ARJ, and Becker DL
- Subjects
- Aged, Aged, 80 and over, Chronic Disease, Humans, Male, Middle Aged, Wounds and Injuries physiopathology, Dermis diagnostic imaging, Diabetic Foot diagnostic imaging, Elasticity Imaging Techniques methods, Extracellular Matrix ultrastructure, Varicose Ulcer diagnostic imaging, Wound Healing physiology, Wounds and Injuries diagnostic imaging
- Abstract
Chronic wounds are a growing problem worldwide with no effective therapeutic treatments available. Our objective was to understand the composition of the dermal tissue surrounding venous leg ulcers and diabetic foot ulcers (DFU). We used novel 2-photon imaging techniques alongside classical histology to examine biopsies from the edges of two common types of chronic wound, venous leg ulcers and DFU. Compared to normal intact skin, we found that collagen levels are significantly reduced throughout the dermis of venous leg ulcer biopsies and DFU, with a reduction in both fibril thickness and abundance. Both wound types showed a significant reduction in elastin in the upper dermis, but in DFU, the loss was throughout the dermis. Loss of extracellular matrix correlated with high levels of CD68- and CD18-positive leukocytes. 2-photon imaging of the extracellular matrix in the intact tissue surrounding a chronic wound with a hand-held device may provide a useful clinical indicator on the healing progression or deterioration of these wounds., (© 2017 Medicalhelplines.com Inc and John Wiley & Sons Ltd.)
- Published
- 2017
- Full Text
- View/download PDF
40. Nonocclusive mesenteric infarction after cardiac surgery: potential biomarkers.
- Author
-
Hong J, Gilder E, Blenkiron C, Jiang Y, Evennett NJ, Petrov MS, Phillips ARJ, Windsor JA, and Gillham M
- Subjects
- Aged, Aged, 80 and over, Biomarkers blood, Female, Humans, Infarction blood, Infarction etiology, Infarction surgery, Intestines blood supply, Laparotomy, Male, Mesenteric Ischemia blood, Mesenteric Ischemia etiology, Mesenteric Ischemia surgery, Middle Aged, Pilot Projects, Postoperative Complications blood, Postoperative Complications surgery, Prospective Studies, ROC Curve, Actins blood, Cardiac Surgical Procedures, Fatty Acid-Binding Proteins blood, Infarction diagnosis, Lactic Acid blood, Mesenteric Ischemia diagnosis, Postoperative Complications diagnosis
- Abstract
Background: Nonocclusive mesenteric ischemia can cause intestinal infarction but the diagnosis is challenging. This prospective study evaluated three plasma biomarkers of intestinal infarction after cardiac surgery., Materials and Methods: Patients were recruited after cardiac surgery if they required laparotomy (with or without intestinal resection) for suspected nonocclusive mesenteric ischemia. Plasma levels of D-lactate, intestinal fatty acid-binding protein (i-FABP), and smooth muscle actin (SMA) before laparotomy were measured., Results: Twenty patients were recruited (68 ± 9 y, EuroSCORE: 8.7 ± 2.8, mortality 70%). A positive laparotomy (n = 13) was associated with no change in D-lactate (P = 0.95), decreased i-FABP (P = 0.007), and increased SMA (P = 0.01). All patients with high SMA had a positive laparotomy. A subgroup analysis was undertaken in the eight patients who required multiple laparotomies. D-lactate increased between the two laparotomies in nonsurvivors (n = 4). Plasma i-FABP (P = 0.008) and SMA (P = 0.036) significantly decreased after the bowel resection, regardless of survival outcome., Conclusions: None of the biomarkers were accurate enough to reliably diagnose intestinal infarction. However, all patients with high values of SMA developed intestinal infarction, thus warranting further investigation. An increasing D-lactate after intestinal resection suggests impending death., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
41. Rutin suppresses human-amylin/hIAPP misfolding and oligomer formation in-vitro, and ameliorates diabetes and its impacts in human-amylin/hIAPP transgenic mice.
- Author
-
Aitken JF, Loomes KM, Riba-Garcia I, Unwin RD, Prijic G, Phillips AS, Phillips ARJ, Wu D, Poppitt SD, Ding K, Barran PE, Dowsey AW, and Cooper GJS
- Subjects
- Amyloid genetics, Animals, Blood Glucose metabolism, Diabetes Mellitus, Experimental drug therapy, Diabetes Mellitus, Experimental genetics, Diabetes Mellitus, Experimental metabolism, Diabetes Mellitus, Experimental pathology, Diabetes Mellitus, Type 2 genetics, Diabetes Mellitus, Type 2 metabolism, Diabetes Mellitus, Type 2 pathology, Humans, Hypoglycemic Agents pharmacology, Islet Amyloid Polypeptide genetics, Islets of Langerhans drug effects, Islets of Langerhans metabolism, Islets of Langerhans pathology, Male, Mice, Transgenic, Protein Aggregation, Pathological drug therapy, Protein Aggregation, Pathological genetics, Protein Aggregation, Pathological metabolism, Protein Aggregation, Pathological pathology, Proteostasis Deficiencies drug therapy, Proteostasis Deficiencies genetics, Proteostasis Deficiencies metabolism, Proteostasis Deficiencies pathology, Rutin pharmacology, Amyloid metabolism, Diabetes Mellitus, Type 2 drug therapy, Hypoglycemic Agents therapeutic use, Islet Amyloid Polypeptide metabolism, Protein Folding drug effects, Rutin therapeutic use
- Abstract
Pancreatic islet β-cells secrete the hormones insulin and amylin, and defective β-cell function plays a central role in the pathogenesis of type-2 diabetes (T2D). Human amylin (hA, also termed hIAPP) misfolds and forms amyloid aggregates whereas orthologous mouse amylin does neither. Furthermore, hA elicits apoptosis in cultured β-cells and β-cell death in ex-vivo islets. In addition, hA-transgenic mice that selectively express hA in their β-cells, manifest β-cell apoptosis and progressive islet damage that leads to diabetes closely resembling that in patients with T2D. Aggregation of hA is thus linked to the causation of diabetes. We employed time-dependent thioflavin-T spectroscopy and ion-mobility mass spectrometry to screen potential suppressors of hA misfolding for anti-diabetic activity. We identified the dietary flavonol rutin as an inhibitor of hA-misfolding and measured its anti-diabetic efficacy in hA-transgenic mice. In vitro, rutin bound hA, suppressed misfolding, disaggregated oligomers and reverted hA-conformation towards the physiological. In hA-transgenic mice, measurements of glucose, fluid-intake, and body-weight showed that rutin-treatment slowed diabetes-progression by lowering of rates of elevation in blood glucose (P = 0.030), retarding deterioration from symptomatic diabetes to death (P = 0.014) and stabilizing body-weight (P < 0.0001). In conclusion, rutin treatment suppressed hA-aggregation in vitro and doubled the lifespan of diabetic mice (P = 0.011) by a median of 69 days compared with vehicle-treated control-diabetic hA-transgenic mice., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
42. Leptin Is Associated With Persistence of Hyperglycemia in Acute Pancreatitis: A Prospective Clinical Study.
- Author
-
Kennedy JIC, Askelund KJ, Premkumar R, Phillips ARJ, Murphy R, Windsor JA, and Petrov MS
- Subjects
- Acute Disease, Adolescent, Adult, Aged, Aged, 80 and over, Biomarkers blood, Disease Progression, Female, Humans, Hyperglycemia blood, Male, Middle Aged, Pancreatitis blood, Pancreatitis physiopathology, Prospective Studies, Severity of Illness Index, Young Adult, Hyperglycemia etiology, Leptin blood, Pancreatitis complications
- Abstract
Adipokines have many homeostatic roles, including modulation of glucose metabolism, but their role in the pathophysiology of hyperglycemia associated with acute and critical illnesses in general, and acute pancreatitis (AP) in particular, is largely unknown. This study aimed to investigate the relationship between a panel of adipokines and hyperglycemia in the early course of AP, as well as the role of adipokines as predictors of AP severity.Adiponectin, leptin, omentin, resistin, and visfatin were measured on a daily basis in the first 72 hours after hospital admission. A first set of analyses was undertaken with admission glycemia stratified by severity, and a second set of analyses was undertaken based on persistence of early hyperglycemia. All of the analyses were adjusted for confounders.A total of 32 patients with AP were included in this study. None of the studied adipokines was significantly associated with glucose level on admission. Leptin was significantly (P = 0.003) increased in patients with persistent hyperglycemia. Adiponectin was significantly associated with the Acute Physiology and Chronic Health Evaluation II (APACHE II) score in patients with persistent hyperglycemia (P = 0.015), visfatin with APACHE II score in patients with persistent hyperglycemia (P = 0.014), and omentin with APACHE II score in all of the patients regardless of the presence or absence of hyperglycemia (P = 0.021).Leptin is significantly associated with persistent hyperglycemia in the early course of AP. Omentin has a potential to become an accurate predictor of AP severity.
- Published
- 2016
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.