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King NE, Courtney JM, Brown LS, Fortune AJ, Blackburn NB, Fletcher JL, Cashion JM, Talbot J, Pébay A, Hewitt AW, Morris GP, Young KM, Cook AL, Sutherland BA. Induced pluripotent stem cell derived pericytes respond to mediators of proliferation and contractility. Stem Cell Res Ther 2024; 15:59. [PMID: 38433209 PMCID: PMC10910734 DOI: 10.1186/s13287-024-03671-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/16/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND Pericytes are multifunctional contractile cells that reside on capillaries. Pericytes are critical regulators of cerebral blood flow and blood-brain barrier function, and pericyte dysfunction may contribute to the pathophysiology of human neurological diseases including Alzheimers disease, multiple sclerosis, and stroke. Induced pluripotent stem cell (iPSC)-derived pericytes (iPericytes) are a promising tool for vascular research. However, it is unclear how iPericytes functionally compare to primary human brain vascular pericytes (HBVPs). METHODS We differentiated iPSCs into iPericytes of either the mesoderm or neural crest lineage using established protocols. We compared iPericyte and HBVP morphologies, quantified gene expression by qPCR and bulk RNA sequencing, and visualised pericyte protein markers by immunocytochemistry. To determine whether the gene expression of neural crest iPericytes, mesoderm iPericytes or HBVPs correlated with their functional characteristics in vitro, we quantified EdU incorporation following exposure to the key pericyte mitogen, platelet derived growth factor (PDGF)-BB and, contraction and relaxation in response to the vasoconstrictor endothelin-1 or vasodilator adenosine, respectively. RESULTS iPericytes were morphologically similar to HBVPs and expressed canonical pericyte markers. However, iPericytes had 1864 differentially expressed genes compared to HBVPs, while there were 797 genes differentially expressed between neural crest and mesoderm iPericytes. Consistent with the ability of HBVPs to respond to PDGF-BB signalling, PDGF-BB enhanced and a PDGF receptor-beta inhibitor impaired iPericyte proliferation. Administration of endothelin-1 led to iPericyte contraction and adenosine led to iPericyte relaxation, of a magnitude similar to the response evoked in HBVPs. We determined that neural crest iPericytes were less susceptible to PDGFR beta inhibition, but responded most robustly to vasoconstrictive mediators. CONCLUSIONS iPericytes express pericyte-associated genes and proteins and, exhibit an appropriate physiological response upon exposure to a key endogenous mitogen or vasoactive mediators. Therefore, the generation of functional iPericytes would be suitable for use in future investigations exploring pericyte function or dysfunction in neurological diseases.
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Affiliation(s)
- Natalie E King
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Jo-Maree Courtney
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Lachlan S Brown
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Alastair J Fortune
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Nicholas B Blackburn
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Jessica L Fletcher
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Jake M Cashion
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Jana Talbot
- Wicking Dementia Education and Research Centre, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Alice Pébay
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Australia
| | - Alex W Hewitt
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Gary P Morris
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Kaylene M Young
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Anthony L Cook
- Wicking Dementia Education and Research Centre, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Brad A Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4, Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia.
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Brown LS, King NE, Courtney JM, Gasperini RJ, Foa L, Howells DW, Sutherland BA. Brain pericytes in culture display diverse morphological and functional phenotypes. Cell Biol Toxicol 2023; 39:2999-3014. [PMID: 37322257 PMCID: PMC10693527 DOI: 10.1007/s10565-023-09814-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/23/2023] [Indexed: 06/17/2023]
Abstract
Pericytes play several important functions in the neurovascular unit including contractile control of capillaries, maintenance of the BBB, regulation of angiogenesis, and neuroinflammation. There exists a continuum of pericyte subtypes along the vascular tree which exhibit both morphological and transcriptomic differences. While different functions have been associated with the pericyte subtypes in vivo, numerous recent publications have used a primary human brain vascular pericytes (HBVP) cell line where this pericyte heterogeneity has not been considered. Here, we used primary HBVP cultures, high-definition imaging, cell motility tracking, and immunocytochemistry to characterise morphology, protein expression, and contractile behaviour to determine whether heterogeneity of pericytes also exists in cultures. We identified five distinct morphological subtypes that were defined using both qualitative criteria and quantitative shape analysis. The proportion of each subtype present within the culture changed as passage number increased, but pericytes did not change morphological subtype over short time periods. The rate and extent of cellular and membrane motility differed across the subtypes. Immunocytochemistry revealed differential expression of alpha-smooth muscle actin (αSMA) across subtypes. αSMA is essential for cell contractility, and consequently, only subtypes with high αSMA expression contracted in response to physiological vasoconstrictors endothelin-1 (ET1) and noradrenaline (NA). We conclude that there are distinct morphological subtypes in HBVP culture, which display different behaviours. This has significance for the use of HBVP when modelling pericyte physiology in vitro where relevance to in vivo pericyte subtypes along the vascular tree must be considered.
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Affiliation(s)
- Lachlan S Brown
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Natalie E King
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Jo-Maree Courtney
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Robert J Gasperini
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Lisa Foa
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
- School of Psychological Sciences, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - David W Howells
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia
| | - Brad A Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Level 4 Medical Sciences Precinct, 17 Liverpool St, Hobart, TAS, 7000, Australia.
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Courtney JM, Morris GP, Cleary EM, Howells DW, Sutherland BA. Automated Quantification of Multiple Cell Types in Fluorescently Labeled Whole Mouse Brain Sections Using QuPath. Bio Protoc 2022; 12:e4459. [PMID: 35937935 PMCID: PMC9303822 DOI: 10.21769/bioprotoc.4459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/27/2022] [Accepted: 05/31/2022] [Indexed: 12/29/2022] Open
Abstract
The quantification of labeled cells in tissue sections is crucial to the advancement of biological knowledge. Traditionally, this was a tedious process, requiring hours of careful manual counting in small portions of a larger tissue section. To overcome this, many automated methods for cell analysis have been developed. Recent advances in whole slide scanning technologies have provided the means to image cells in entire tissue sections. However, common automated analysis tools do not have the capacity to deal with the large image files produced. Herein, we present a protocol for the quantification of two fluorescently labeled cell populations, namely pericytes and microglia, in whole brain tissue sections. This protocol uses custom-made scripts within the open source software QuPath to provide a framework for the careful optimization and validation of automated cell detection parameters. Images obtained from a whole-slide scanner are first loaded into a QuPath project. Manual counts are performed on small sample regions to optimize cell detection parameters prior to automated quantification of cells across entire brain regions. Even though we have quantified pericytes and microglia, any fluorescently labeled cell with clear labeling in and around the nucleus can be analyzed using these methods. This protocol provides a user-friendly and cost-effective framework for the automated analysis of whole tissue sections.
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Affiliation(s)
- Jo-Maree Courtney
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Gary P. Morris
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Elise M. Cleary
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - David W. Howells
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Brad A. Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
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*For correspondence:
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Affiliation(s)
- Jo-Maree Courtney
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Brad A Sutherland
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
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Liu Y, Michalska AE, Dottori M, Eaton E, Courtney JM, Antonic A, Howells DW. Differential susceptibility of human neural progenitors and neurons to ischaemic injury. Brain Res Bull 2019; 156:25-32. [PMID: 31837459 DOI: 10.1016/j.brainresbull.2019.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 11/10/2019] [Accepted: 12/10/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND Neuroprotection for stroke has shown great promise but has had little translational success. Developing drugs for humans logically requires human tissue evaluation. Human embryonic stem cell (hESC)-derived neuronal cultures at different developmental stages were subject to oxygen glucose deprivation (OGD) to determine how developing maturity altered response to ischemic injury. METHODS H9 hESCs were induced by Noggin to generate neural progenitors (NPs) and highly arbourised structurally complex neurons. They were both subjected to OGD or OGD with reoxygenation (OGD-R) for 1-6 h.Outcome was assessed by measures of cell death, survival and morphology. RESULTS NPs did not die after OGD but experienced progressive loss of metabolic activity. Highly arbourised neurons showed minimal cell death initially but 44 % and 78 % died after 4 and 6 h OGD. Metabolic dysfunction was greater in these more mature neurons (∼70 %) than in NPs and evident after 1 h OGD, before detection of neuronal death at 4 h. OGD-R salvaged metabolic activity but not cell death in mature neurons. In NPs there was little metabolic salvage and cell death was induced (50 % and 65 % at 4 and 6 h OGD-R, respectively). CONCLUSIONS Highly arbourised neurons are more sensitive to ischaemic injury than NPs which did however develop marked vulnerability to prolonged injury with reoxygenation. These observations imply that therapeutic potential may be highly dependent of the developmental state of the neurons we aim to protect.
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Affiliation(s)
- Ye Liu
- Department of Neurology, Huashan Hospital, Shanghai, 200040, China; Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200433, China
| | - Anna E Michalska
- Stem Cell Core Facility, Stem Cells Australia, The University of Melbourne, Victoria, 3010, Australia
| | - Mirella Dottori
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, 2522 Australia
| | - Emma Eaton
- School of Medicine, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Jo-Maree Courtney
- School of Medicine, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Ana Antonic
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Centre, VIC 3004, Australia
| | - David W Howells
- School of Medicine, University of Tasmania, Hobart, Tasmania, 7001, Australia.
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Brown LS, Foster CG, Courtney JM, King NE, Howells DW, Sutherland BA. Pericytes and Neurovascular Function in the Healthy and Diseased Brain. Front Cell Neurosci 2019; 13:282. [PMID: 31316352 PMCID: PMC6611154 DOI: 10.3389/fncel.2019.00282] [Citation(s) in RCA: 200] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/11/2019] [Indexed: 12/11/2022] Open
Abstract
Pericytes are multi-functional cells embedded within the walls of capillaries throughout the body, including the brain. Pericytes were first identified in the 1870s, but little attention was paid to them during the following century. More recently, numerous vascular functions of pericytes have been identified including regulation of cerebral blood flow, maintenance of the blood-brain barrier (BBB), and control of vascular development and angiogenesis. Pericytes can also facilitate neuroinflammatory processes and possess stem cell-like properties. Pericytes form part of the neurovascular unit (NVU), a collection of cells that control interactions between neurons and the cerebral vasculature to meet the energy demands of the brain. Pericyte structure, expression profile, and function in the brain differ depending on their location along the vascular bed. Until recently, it has been difficult to accurately define the sub-types of pericytes, or to specifically target pericytes with pharmaceutical agents, but emerging techniques both in vitro and in vivo will improve investigation of pericytes and allow for the identification of their possible roles in diseases. Pericyte dysfunction is increasingly recognized as a contributor to the progression of vascular diseases such as stroke and neurodegenerative diseases such as Alzheimer’s disease. The therapeutic potential of pericytes to repair cerebral blood vessels and promote angiogenesis due to their ability to behave like stem cells has recently been brought to light. Here, we review the history of pericyte research, the present techniques used to study pericytes in the brain, and current research advancements to characterize and therapeutically target pericytes in the future.
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Affiliation(s)
- Lachlan S Brown
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Catherine G Foster
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Jo-Maree Courtney
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Natalie E King
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - David W Howells
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Brad A Sutherland
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
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Bowry SK, Prentice CRM, Courtney JM. A Modification of the Wu and Hoak Method for the Determination of Platelet Aggregates and Platelet Adhesion. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1661319] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryThe Wu and Hoak method for determining circulating platelet aggregates has poor reproducibility; problems have been reported with the composition of the buffer systems, haemolysis, the effects of blood collection technique and a divergence of the platelet aggregate ratio in blood for healthy donors from the theoretical value of 1. Our investigations suggest that the original technique is highly operator-dependent, especially the collection of blood and the method of counting platelets after centrifugation. We describe an improved modification of the Wu and Hoak technique; a new buffer system has been developed and the proportion of blood in the buffered EDTA and buffered EDTA- formalin solutions has been altered to obtain platelet rich plasma. The platelet aggregate ratio (PAR) by this modified method for healthy donors in two different studies was 0.97 ± 0.02 and 0.98 ± 0.01 respectively. Finally, the principle of Wu and Hoak was used to measure accurately platelet adhesion, without the role of platelet-platelet interactions (aggregation). Platelet adhesion and aggregation were then used to evaluate the thrombogenicity of various artificial surfaces, including silicone rubber and polytetra- fluoroethylene (PTFE) vascular grafts.
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Affiliation(s)
- Sudhir K Bowry
- The Bioengineering Unit, University of Strathclyde, Glasgow, Scotland
| | | | - J M Courtney
- The Bioengineering Unit, University of Strathclyde, Glasgow, Scotland
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Courtney JM, Spafford PL. The Role of Epithelial-Mesenchymal Transition in Chronic Obstructive Pulmonary Disease. Cells Tissues Organs 2017; 203:99-104. [PMID: 28214877 DOI: 10.1159/000450919] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2016] [Indexed: 11/19/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a major cause of mortality worldwide, and there is currently no treatment that can halt the progression of the disease. Over the last decade there has been increasing interest in the idea that epithelial-mesenchymal transition (EMT) may be active in COPD. Here we review the evidence for EMT in COPD as well as the current progress being made on understanding the drivers and mechanisms involved. Finally, we discuss the potential benefits that understanding EMT may bring to the field of chronic respiratory disease.
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Affiliation(s)
- Jo-Maree Courtney
- NHMRC Centre of Research Excellence for Chronic Respiratory Disease and Lung Aging, School of Medicine, University of Tasmania, Hobart, TAS, Australia
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Falkenhagen D, Gottschall S, Esther G, Courtney JM, Klinkmann H. In vitro assessment of charcoal and resin hemoadsorbents. Contrib Nephrol 2015; 29:23-33. [PMID: 7075214 DOI: 10.1159/000406175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An in vitro assessment has been made of the blood compatibility and efficiency of different charcoal and resin hemoadsorbents. The charcoals vary in source, shape, size, nature and amount of polymer coating. The resins are the macroreticular adsorbents XAD-4 and Y56 and a carbonized resin. The effect on Y56 of albumin coating has been studied. The assessment has demonstrated that a reduction in platelet drop is accompanied by a decrease in the adsorption of fibrinogen. The results confirm the potential advantages of spherical charcoal and that coating with an ultrathin layer of polymer or with albumin does not seriously reduce efficiency. For Y56 resin, treatment with an albumin solution of 1-2 g/100 ml appears to be a suitable procedure if clinical use is considered.
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Courtney JM, Kelly MG, Watt A, Garske L, Bradley J, Ennis M, Elborn JS. Quality of life and inflammation in exacerbations of bronchiectasis. Chron Respir Dis 2008; 5:161-8. [DOI: 10.1177/1479972308091823] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Patients with bronchiectasis often have impaired quality of life (QoL), which deteriorates with exacerbations. The aim of this study was to investigate changes in QoL and how these were influenced by changes in airway physiology and inflammation in patients with bronchiectasis before and after resolution of an exacerbation. Sputum induction and a QoL questionnaire were undertaken on the first day, day 14, and 4 weeks after completion of intravenous antibiotics (day 42). Eighteen patients (12 female) were recruited, median (IQ range) age of 54 (47–60) years. There was a trend towards an improvement in lung function from visit 1 to visit 2, but this was not statistically significant. C-reactive protein (CRP) [mean (SEM)] reduced between visit 1 and visit 2 [55.4 (21.5) vs 9.4 (3.1) mg/L, P = 0.03] but did not increase significantly on visit 3 [44.4 (32.9) mg/L, P = 0.27]. The median (interquartile range) sputum cell count (×106 cells/g of sputum) decreased from visit 1 to visit 2 [21.6 (11.8–37.6)–13.3 (6.7–22.9) × 106 cells/g, respectively, P = 0.008] and increased from visit 2 to visit 3 [26.3 (14.1–33.6) × 106 cells/g, P = 0.03]. All soluble markers of inflammation significantly reduced from visit 1 to visit 2 but increased on visit 3 with the exception of TNF-α. Regarding QoL, three of the four domains (dyspnoea, emotional, mastery) significantly improved from visit 1 to visit 2 but did not change between visit 2 and visit 3. The improvements in QoL scores could not be explained by the improvements in lung function or inflammatory markers.
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Affiliation(s)
- JM Courtney
- Respiratory Research Centre, Belfast City Hospital, Belfast, Northern Ireland; Respiratory Medicine Research Cluster, Queen’s University Belfast, Belfast, Northern Ireland
| | - MG Kelly
- Respiratory Research Centre, Belfast City Hospital, Belfast, Northern Ireland; Respiratory Medicine Research Cluster, Queen’s University Belfast, Belfast, Northern Ireland
| | - A Watt
- Respiratory Medicine Research Cluster, Queen’s University Belfast, Belfast, Northern Ireland
| | - L Garske
- Respiratory Research Centre, Belfast City Hospital, Belfast, Northern Ireland
| | - J Bradley
- Health and Rehabilitation Sciences Research Institute, University of Ulster, Belfast, Northern Ireland
| | - M Ennis
- Respiratory Medicine Research Cluster, Queen’s University Belfast, Belfast, Northern Ireland
| | - JS Elborn
- Respiratory Research Centre, Belfast City Hospital, Belfast, Northern Ireland; Respiratory Medicine Research Cluster, Queen’s University Belfast, Belfast, Northern Ireland
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Abstract
Assessment of prognostic indicators in patients with cystic fibrosis (CF) is important. The study's aim was to assess the relative contribution of gender, genetics and microbiology on survival in adults with CF. Adult patients were studied from 1995 to 2005 and data collected included FEV(1) (%predicted), body mass index (BMI), genetics, and microbiology. Data was available on 183 patients in 1995. Forty-five patients died in the subsequent 10 years. Patients who died during the study had lower mean (SD) FEV(1) %predicted in 1995 when compared to those remaining alive, 41.5 (15.2)% versus 69.8 (23.2)% predicted, respectively, P<0.001 and they had lower mean (SD) BMI in 1995, 19.2 (3.3) kg/m(2) in comparison to those remaining alive, 20.7 (3.4) kg/m(2), P=0.008. The proportion of patients infected with Pseudomonas aeruginosa and Burkholderia cepacia complex was higher in the group who died during the study compared to those remaining alive, odds ratio 20.9 P<0.0001 and 7.1 P<0.0001, respectively. The presence of the Delta F508 homozygous mutation did not alter survival, P=0.3. Patients infected with either P.aeruginosa or B.cepacia complex had reduced survival compared to those without infection, P=0.01 and P<0.0001, respectively. FEV(1)% (P<0.0001), infection with P.aeruginosa (P=0.005) or B.cepacia complex (P=0.03) were the only significant predictors of mortality. This study demonstrates adults who died were more likely to have worse lung function and be infected with either P.aeruginosa or B.cepacia complex. FEV(1)% and infection with P.aeruginosa or B.cepacia complex were the most significant predictors of survival in adults with CF.
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Affiliation(s)
- J M Courtney
- Adult Cystic Fibrosis Unit, Belfast City Hospital, Belfast, Northern Ireland, Ireland.
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Abstract
Hypohidrotic ectodermal dysplasia (HED) is a congenital disorder affecting organs of ectodermal origin including teeth, hair and sweat glands. Defects in Ectodysplasin (tabby), Edar (downless) and Edar associated death domain (Edaradd) (crinkled) cause HED in both humans and mice. Ectodysplasin is a tumour necrosis factor (TNF) superfamily member whose downstream signalling is transduced by the inhibitor of kappaB kinase (IKK) complex and inhibitors of kappaB (IkappaB) to activate the transcription factor NFkappaB. NFkappaB signalling is involved in a wide range of cellular processes and at each stage the different family members must be tightly regulated for each function. Recent data have demonstrated the importance of this signalling pathway in odontogenesis, particularly in the formation of cusps. Here we review recent advances in our understanding of Ectodysplasin/NFkappaB signalling in tooth development and in particular the central role of the IKK complex.
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Affiliation(s)
- Jo-Maree Courtney
- Craniofacial Development, Kings College London, Floor 28 Guy's Tower, Guy's Hospital, London Bridge, London SE1 9RT, UK
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Abstract
Airway disease in cystic fibrosis (CF) is characterised by a continuous cycle of chronic infection and inflammation dominated by a neutrophilic infiltrate. This inflammation is characterised by an increased production of pro-inflammatory cytokines in the lung. The relationship between the abnormal CFTR gene product and the development of inflammation and progression of lung disease in CF is not fully understood. This review article studied the mechanisms of pulmonary inflammation in CF, the profiles of cytokines and inflammatory mediators in the lung in CF, the mechanisms that predispose to chronic Pseudomonas aeruginosa infection, cytokine involvement in diseases other than CF and reviewed current therapeutic strategies for CF. Imbalances of cytokine secretion are now better understood due to recent advances in understanding CF at a molecular level and it is increasingly thought that the normal inflammatory process is deranged in CF early in the course of the disease and may occur in the absence of detectable infection. However, the relationship between this unbalanced cytokine production, the mutations in CFTR and its actual consequence for pathogenesis need further investigation.
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Affiliation(s)
- J M Courtney
- Adult Cystic Fibrosis Centre, Belfast City Hospital, Lisburn Road, Belfast BT9 7AB, Northern Ireland, UK
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Courtney JM, Dunbar KEA, McDowell A, Moore JE, Warke TJ, Stevenson M, Elborn JS. Clinical outcome of Burkholderia cepacia complex infection in cystic fibrosis adults. J Cyst Fibros 2004; 3:93-8. [PMID: 15463892 DOI: 10.1016/j.jcf.2004.01.005] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2003] [Accepted: 01/28/2004] [Indexed: 11/20/2022]
Abstract
BACKGROUND The Burkholderia cepacia complex (BCC) is one of the most important groups of organisms infecting cystic fibrosis (CF) patients. The aim of the study was to examine how infection with BCC affects clinical outcome. METHODS Nineteen CF adults infected with BCC and 19 controls infected with Pseudomonas aeruginosa were studied over a 4-year period. The best forced expiratory volume in 1 s (FEV(1)) and body mass index (BMI) for each year were recorded and annual rate of decline calculated. RESULTS The BCC infected group displayed a significantly greater reduction of FEV(1) and BMI compared to the P. aeruginosa infected group (p=0.001 and p=0.009, respectively). Sixteen patients infected with a single Burkholderia cenocepacia strain had a significantly greater rate of FEV(1) decline compared to those infected with Burkholderia multivorans (n=3) or P. aeruginosa (p=0.01 and p<0.0001, respectively). The rate of BMI decline was significantly greater in patients infected with B. cenocepacia compared to those with P. aeruginosa (p=0.007), but not significantly different in those with B. multivorans (p=0.29). CONCLUSION BCC infection is associated with an accelerated decline in pulmonary function and BMI. Infection with a single B. cenocepacia strain was associated with a more rapid decline in lung function than those infected with either B. multivorans or P. aeruginosa.
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Affiliation(s)
- J M Courtney
- Adult Cystic Fibrosis Centre, Belfast City Hospital, Lisburn Road, Belfast BT9 7AB, North Ireland, UK
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16
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Zhao XB, Courtney JM. Blood response to plasticized poly(vinyl chloride): dependence of fibrinogen adsorption on plasticizer selection and surface plasticizer level. J Mater Sci Mater Med 2003; 14:905-912. [PMID: 15348529 DOI: 10.1023/a:1025690828200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The high level of plasticizer in plasticized poly(vinyl chloride) (PVC) ensures that plasticizer selection has an important influence on the suitability of PVC to function in blood-contacting applications. In this study, three types of plasticized PVC in sheet form, with di-(2-ethylhexyl)phthalate (DEHP), tri-(2-ethylhexyl)trimellitate (TEHTM) and n-butyryltri-n-hexyl citrate (BTHC) as plasticizer, were selected for assessment and single solute fibrinogen adsorption was utilized as an initial index of interactions with blood components. Fibrinogen adsorption behavior shows a strong dependence on the plasticizer selection, plasticizer level at the surface and the adsorption conditions, such as adsorption time and fibrinogen solution concentration. Results indicate that BTHC plasticized PVC possesses the lowest adsorption capacity in the three types of plasticized PVC, while TEHTM plasticized PVC seems to have the strongest reactivity in certain fibrinogen solution concentrations. The alteration of surface plasticizer level was achieved by a methanol-cleaning treatment with a variety of cleaning times and the fibrinogen adsorption on plasticized PVC decreases with the reduction of surface plasticizer level. The migration behavior of two phthalate esters (DEHP and TEHTM) was evaluated using UV-Spectrophotometer to determine the plasticizer level at the surfaces. In addition, the fibrinogen adsorption mechanism was examined with Freundlich adsorption modeling.
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Affiliation(s)
- X B Zhao
- Bioengineering Unit, University of Strathclyde, Glasgow G4 0NW, UK
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17
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Abstract
Tumor necrosis factor receptor-associated factors (TRAFs) belong to a family of intracellular adaptor proteins that mediate signaling downstream of various cell surface receptors. We carried out comparative in situ hybridization analysis of five Traf genes Traf1, Traf2, Traf3, Traf4 and Traf6 during murine odontogenesis from the formation of the epithelial thickening to the early bell stage. Traf2, Traf3 and Traf6 showed weak expression in the thickened epithelium. Expression of Traf1, Traf2 and Traf6 were observed in the outer edges of the bud epithelium whereas Traf3 was strongly expressed at the tip of the bud epithelium. Expression of Traf1, Traf4 and Traf6 were detected in the dental papilla mesenchyme. Traf2 showed restricted expression in the internal enamel epithelium of the bell stage while expression of Traf1, Traf3, Traf4 and Traf6 were observed in both the internal and the external enamel epithelium. During early odontogenesis, all five genes show dynamic spatiotemporal expression patterns.
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Affiliation(s)
- Atsushi Ohazama
- Department of Craniofacial Development, GKT Dental Institute, King's College London, Guy's Hospital, Floor 28, Guy's Tower, London Bridge, London SE1 9RT, UK
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18
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Abstract
Modification of polymer surfaces to achieve a surface with enhanced compatibility is an important means of obtaining improved biomaterials. Techniques are available for altering the hydrophilicity or charge of a surface, attaching macromolecules or attempting to resemble cell membranes. Relevant to the clinical success of a modified surface is the modification procedure and a procedure based on incorporation as opposed to surface treatment has potential advantages. The modification of plasticized vinyl chloride (PVC) by the incorporation of cyclodextrins is described. In comparison to unmodified PVC controls, cyclodextrin incorporation reduced fibrinogen adsorption, with the extent of reduction dependent on the type and quantity of cyclodextrin incorporated.
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK.
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19
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Abstract
Ectodermal appendages such as skin, hair, teeth, and sweat glands are affected in patients with hypohidrotic (anhydrotic) ectodermal dysplasia (HED). It has been established that mutations in the tumor necrosis factor (TNF) superfamily of molecules, i.e., ectodysplasin (EDA), EDA receptor (EDAR), and EDAR-associated death domain (EDARADD; the intracellular adaptor for EDAR), are responsible for several forms of HED in humans and mice. We show here by in situ hybridisation that another TNF family (orphan) receptor, TROY (also known TAJ, TAJ-alpha, TRADE, and TNFRSF19), is strongly coexpressed with Edar in the epithelial enamel knot signalling centres that are believe to regulate cuspal morphogenesis during murine tooth development. Traf6 is known to function as an intracellular adaptor protein for Troy and examination of Traf6 mutant mice revealed abnormalities in molar teeth that are similar but more severe than those produced by mutations in Eda signalling molecules. This finding suggests that, in additional to ectodysplasin, another TNF pathway involving Troy/Traf6 is involved in molar tooth cusp formation and identifies an essential role for a Traf in tooth development. Developmental Dynamics 229:131-135, 2004.
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Affiliation(s)
- Atsushi Ohazama
- Department of Craniofacial Development, GKT Dental Institute, King's College, Guy's Hospital, London Bridge, London, United Kingdom
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20
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Brodbeck J, Davies A, Courtney JM, Meir A, Balaguero N, Canti C, Moss FJ, Page KM, Pratt WS, Hunt SP, Barclay J, Rees M, Dolphin AC. The ducky mutation in Cacna2d2 results in altered Purkinje cell morphology and is associated with the expression of a truncated alpha 2 delta-2 protein with abnormal function. J Biol Chem 2002; 277:7684-93. [PMID: 11756448 DOI: 10.1074/jbc.m109404200] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mouse mutant ducky, a model for absence epilepsy, is characterized by spike-wave seizures and cerebellar ataxia. A mutation in Cacna2d2, the gene encoding the alpha 2 delta-2 voltage-dependent calcium channel accessory subunit, has been found to underlie the ducky phenotype. The alpha 2 delta-2 mRNA is strongly expressed in cerebellar Purkinje cells. We show that du/du mice have abnormalities in their Purkinje cell dendritic tree. The mutation in alpha 2 delta-2 results in the introduction of a premature stop codon and predicts the expression of a truncated protein encoded by the first three exons of Cacna2d2, followed by 8 novel amino acids. We show that both mRNA and protein corresponding to this predicted transcript are expressed in du/du cerebellum and present in Purkinje cells. Whereas the alpha 2 delta-2 subunit increased the peak current density of the Ca(V)2.1/beta(4) channel combination when co-expressed in vitro, co-expression with the truncated mutant alpha 2 delta-2 protein reduced current density, indicating that it may contribute to the du phenotype.
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Affiliation(s)
- Jens Brodbeck
- Department of Pharmacology, University College London, Gower Street, London WC1E, United Kingdom
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21
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Ryan CJ, Anilkumar T, Ben-Hamida AJ, Khorsandi SE, Aslam M, Pusey CD, Gaylor JD, Courtney JM. Multisorbent plasma perfusion in fulminant hepatic failure: effects of duration and frequency of treatment in rats with grade III hepatic coma. Artif Organs 2001; 25:109-18. [PMID: 11251476 DOI: 10.1046/j.1525-1594.2001.025002109.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Using the model of galactosamine-induced fulminant hepatic failure in the rat, the effects of multisorbent plasma perfusion over Asahi uncoated spherical charcoal, Plasorba (BR-350) resin, and an endotoxin removing adsorbent (polymyxin B-sepharose) were determined in Grade III hepatic coma animals by studying survival as influenced by timing, duration, and frequency of treatment. The effects of treatment on liver cell proliferation and endotoxin removal also were examined. The results demonstrate that duration and frequency of treatment are major contributing factors in the successful application of nonbiological membrane-based multisorbent liver support systems. Examination of the regenerative activity in the liver indicates an enhanced proliferative response following multisorbent plasma perfusion compared with untreated fulminant hepatic failure (FHF) paired controls. Utilizing an endotoxin removal adsorbent alone, a marked reduction in systemic levels of endotoxin in FHF was demonstrated compared with nonperfused FHF paired controls. Despite current emphasis on bioartificial liver support systems, plasma purification by multisorbent systems offers a simple method for the removal of circulating toxic metabolites in general together with specific toxin removal.
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Affiliation(s)
- C J Ryan
- Division of Surgery, Anaesthetics, and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital Campus, London, UK
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22
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Affiliation(s)
- A K Mahmood
- Bioengineering Unit, University of Strathclyde, Glasgow.
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23
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Courtney JM, Murphy SM, Robertson LM, Ryan CJ, Tighe BJ. Examination of particulate macroporous hydrogels in an extracorporeal rat haemoperfusion model. J Biomater Sci Polym Ed 2000; 10:1063-77. [PMID: 10606026 DOI: 10.1163/156856299x00748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A series of macroporous hydrogels has been synthesized, selected from a range of such materials in which the presence of functional groups has been shown to produce sorbent properties with respect to molecules having clinical significance in the field of liver support. The use of freeze thaw polymerization, together with inverse suspension polymerization in hexane, or in brine, enables macroporous beads ranging in size from 150 to 2000 microm, to be prepared from functional monomers exhibiting a range of chemical functionalities and aqueous solubilities. In order to investigate the behaviour of these rigid porous hydrophilic substrates in haemoperfusion, a rat model was used to explore various aspects of whole blood response. The materials were incorporated into an extracorporeal circuit linking the right carotid artery and left jugular vein of male Sprague-Dawley rats. Erythrocyte, leucocyte and platelet levels were monitored over a 240 min haemoperfusion period. The most significant observation is that, apart from the strongly acidic polyacrylic acid substrate. matrix chemistry has relatively little effect on leucocyte or platelet response. The most important factors appear to be surface area, pore size and surface rugosity, which do produce measurable, but not dramatic differences. This is encouraging for future work, since these variables may be manipulated by polymerization conditions.
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Affiliation(s)
- J M Courtney
- University of Strathclyde, Bioengineering Unit, Glasgow, UK
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24
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Lamba NM, Courtney JM, Gaylor JD, Lowe GD. In vitro investigation of the blood response to medical grade PVC and the effect of heparin on the blood response. Biomaterials 2000; 21:89-96. [PMID: 10619682 DOI: 10.1016/s0142-9612(99)00145-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This paper reports the results of an investigation into the blood response of polymers in vitro, using non-anticoagulated and heparinised blood and plasma. The materials studied were regenerated cellulose, (Cuprophan), an acrylonitrile-allyl sulphonate copolymer (AN69S), and medical grade polyvinyl chloride plasticised with di-2-ethyl-hexyl-phthalate (PVC/DEHP). Blood-material or plasma-material contact was achieved using a parallel plate flow cell, and C3a generation and FXII-like activity measured. The results of the study with non-anticoagulated human blood show that PVC/DEHP is a high complement activator. C3a concentration in the blood was higher after contact with PVC/DEHP than after contact with regenerated cellulose. The introduction of heparin in the blood induced complex alterations in the blood response. C3a generation could be elevated, decreased, or remain the same, depending on the material. The FXII-like activity on the surface of the PVC/DEHP after contact with plasma was also higher than the other two polymers. The introduction of heparin could increase or decrease FXII-like activity, depending on material. The patterns of response obtained with non-anticoagulated blood in vitro for AN69S and Cuprophan bore a strong resemblance with patterns of response obtained in the clinic, whereas those obtained with heparinised blood in vitro did not.
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Affiliation(s)
- N M Lamba
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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25
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Yin HQ, Zhao XB, Courtney JM, Blass CR, West RH, Lowe GD. Blood interactions with plasticized poly(vinyl chloride): relevance of plasticizer selection. J Mater Sci Mater Med 1999; 10:527-531. [PMID: 15348103 DOI: 10.1023/a:1008912213420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An investigation has been made of blood interactions with plasticized poly(vinyl chloride) (PVC) biomaterials in tubular form, taking into account the influence on the blood response of the polymer, antithrombotic agent, blood condition and test procedure. In vitro and ex vivo procedures were used to achieve a comparison between PVC plasticized with di- (2-ethylhexyl)phthalate (DEHP) and with tri-(2-ethylhexyl)trimellitate (TEHTM). The blood response was monitored in terms of the measurement of fibrinogen adsorption capacity, thrombin-antithrombin III complex (TAT) and the complement component C3a. Surface characterization of the polymers was performed by X-ray photoelectron spectroscopy (XPS). The data obtained indicate that in comparison with DEHP-PVC, there is a higher reactivity for TEHTM-PVC, which correlates with the plasticizer distribution at the polymer surface.
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Affiliation(s)
- H Q Yin
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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26
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK.
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27
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Abstract
An investigation has been made of the significance of the level of the plasticizer di-(2-ethylhexyl)phthalate at the surface of plasticized polyvinyl chloride for interactions with blood components. Plasticized polyvinyl chloride before and after treatment with methanol to reduce the plasticizer surface level was assessed in terms of fibrinogen and albumin adsorption with unplasticized polyvinyl chloride acting as a control. As the plasticizer surface level decreased, fibrinogen adsorption decreased almost linearly while albumin adsorption increased initially before decreasing slightly. The investigation indicates that reduction in the amount of plasticizer at the surface improves the blood compatibility of plasticized polyvinyl chloride, and the influence on blood is due primarily to the plasticizer rather than the polyvinyl chloride itself.
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Affiliation(s)
- X Zhao
- Bioengineering Unit, University of Strathclyde, Glasgow, United Kingdom
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28
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Lamba NM, Gaylor JD, Courtney JM, Lowe GD. Complement activation by cellulose: investigation of the effects of time, area, flow rate, shear rate and temperature on C3a generation in vitro, using a parallel plate flow cell. J Mater Sci Mater Med 1998; 9:409-414. [PMID: 15348869 DOI: 10.1023/a:1013287614418] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The development and utilization of a parallel plate flow system to study the blood response to flat sheet biomaterials, is described. Unlike most other parallel plate flow systems, which have been used to study cellular interactions with biomaterials, the controlled flow test cell described below employs the test materials on both sides of the channel through which the blood flows. The flow cell is used to conduct an investigation into the in vitro generation of C3a by a regenerated cellulose membrane, Cuprophan. The effects of experimental variables such as temperature, blood flow rate, contact area and wall shear rate on C3a generation by Cuprophan were studied. The results show that C3a generation by Cuprophan is lower at 12 degrees C than at 22 degrees C, which is in turn lower than C3a generation at 37 degrees C. Furthermore, a decrease in contact area, and increase in wall shear rate and blood flow rate, can produce a decrease in C3a concentration.
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Affiliation(s)
- N M Lamba
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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29
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Zhao XB, Qian H, Courtney JM. Artificial cell containing superoxide dismutase--selection of folding aids for stabilisation of SOD. Artif Cells Blood Substit Immobil Biotechnol 1998; 26:341-58. [PMID: 9663333 DOI: 10.3109/10731199809117676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Superoxide dismutase (abbreviated as SOD) has been vigorously studied in the fields of radical chemistry and related life science. One of practical problems is how to keep its activity in certain adverse conditions causing denaturation. Artificial cell containing SOD can be prepared by polymer encapsulation or nanocapsulation which has been found to be effective to improve the stability of SOD. For construction of an ideal artificial cell system, some folding aids or aggregation inhibitors were utilised to enhance SOD stability. In this study, three groups of biopolymers are selected as folding aids or aggregation inhibitors for stabilisation of SOD, i.e. albumin, carbohydrates and glycoproteins. Results indicate that the thermostability of SOD is affected by different sort of albumin while some carbohydrates such as cyclodextrins are found to be able to enhance SOD stability. In addition, it is firstly found that selected glycoproteins such as alpha-macroglobulin and ovalbumin are several types of effective folding aids for stabilisation of SOD. They can protect SOD against denaturation even at very high temperature(over 100 degrees C). The stability was tested by the measurement of SOD activity loss using autooxidation method in different adverse conditions such as high temperature, extreme pH medium, proteolytic hydrolysis and long shelf life storage. The possible stabilisation mechanism of using cyclodextrins and glycoproteins as folding aids were discussed.
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Affiliation(s)
- X B Zhao
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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30
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Mahiout A, Matata BM, Vienken J, Courtney JM. Ex vivo complement protein adsorption on positively and negatively charged cellulose dialyser membranes. J Mater Sci Mater Med 1997; 8:287-296. [PMID: 15348751 DOI: 10.1023/a:1018560211844] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An ex vivo test system was used to measure complement protein C3 and factor B adsorption onto small dialyser modules made from regenerated and modified cellulosic hollow fibre membranes in which positive diethylaminoethyl (DEAE) or negative carboxymethyl (CM) groups were introduced into the cellulose matrix. The extracorporeal system, which included test-dialysers and the dialysis environment, allowed the use of labelled proteins without contaminating the blood donors which were connected in an open-loop fashion to the extracorporeal test system. The modules were removed at selected time points from the extracorporeal system for radioactivity counting. The results were used to evaluate the mechanisms involved in complement reactions to foreign surfaces. The system therefore allowed the analysis of complement protein adsorption occurring in the dialyser modules and its relationship to the complement generation rate in the extracorporeal system to be evaluated. It was possible to demonstrate that significant complement C3 and factor B adsorption occurred in the test modules made of cellulosic membranes. Complement adsorption as a function of the pH and the release reaction of the adsorbed C3 and factor B after membrane blood perfusion were therefore found to be variable according to the cellulosic membrane type and the presence of positive or negative charged groups within the cellulose matrix. The data obtained from the ex vivo model therefore provided additional evidence on the discussion of the mechanisms involved in the increased complement activation by regenerated cellulose and in its attenuation by DEAE- or CM-modified cellulose.
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Affiliation(s)
- A Mahiout
- Institute of Cell & Protein Engineering, Medical Park Hannover, Germany
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31
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Matata BM, Yin HQ, Courtney JM, Gaylor JD, Lamba NM, Lowe GD, Suzuki K, Kimura H, Izumi K, Klinkmann H. In vitro blood compatibility evaluation of hollow fibre membrane using a controlled flow system: a comparative study. Int J Artif Organs 1996; 19:582-9. [PMID: 8946234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A procedure has been established for the in vitro assessment of hollow fibre haemodialysis membranes. A 30 ml syringe containing 20 ml of fresh non-anticoagulated blood was mounted onto a non-pulsatile syringe pump and blood was perfused through minimodules constructed from 80 fibres retrieved from Cuprophan (Baxter ST15), cellulose acetate (M57-12, JMS Co Ltd, Hiroshima, Japan), and AN69HF (Filtral 20, Hospal, France) dialysers. Samples were collected before perfusion, 3, 6, 9 and 12 minutes. The modules were clamped vertically to minimise the effect of red cell pooling and the dialysate compartment was filled with 0.9% saline to minimise ultrafiltration. After sample processing, complement C3a, thrombin-antithrombin III complexes, prothrombin F1 + 2, and factor XII-like activity were evaluated. The results indicated that the system could discriminate between the membranes evaluated and therefore was a relevant procedure for the assessment of hollow fibre haemodialysis membranes.
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Affiliation(s)
- B M Matata
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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32
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Courtney JM, Matata BM, Yin HQ, Esposito A, Mahiout A, Taggart DP, Lowe GD. The influence of biomaterials on inflammatory responses to cardiopulmonary bypass. Perfusion 1996; 11:220-8. [PMID: 8817630 DOI: 10.1177/026765919601100307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The nature of cardiopulmonary bypass and the complexity of the inflammatory response make the detection and interpretation of a biomaterial influence difficult. However, if mediation of the inflammatory response is considered to be an appropriate clinical goal, alteration to the biomaterial influence merits further investigation.
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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33
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Matata BM, Courtney JM, Sundaram S, Wark S, Bowry SK, Vienken J, Lowe GD. Determination of contact phase activation by the measurement of the activity of supernatant and membrane surface-adsorbed factor XII (FXII): its relevance as a useful parameter for the in vitro assessment of haemodialysis membranes. J Biomed Mater Res 1996; 31:63-70. [PMID: 8731150 DOI: 10.1002/(sici)1097-4636(199605)31:1<63::aid-jbm8>3.0.co;2-o] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We investigated hemodialysis membrane biocompatibility with respect to contact phase activation by determination of FXII-like activity (FXIIA) on the membrane surface and in the supernatant phase, during plasma contact with various hemodialysis membranes using an in vitro incubation test cell. The results were compared to the influence of these membranes on the activation of purified FXII. A time course for the generation of activated FXII using purified FXII solution at physiologic concentrations on two similar negatively charged polymers was performed. The membranes assessed were regenerated cellulose (Cuprophan; Akzo Faser AG, Germany), modified cellulosic (Hemophan; Akzo Faser AG), acrylonitrile-sodium methallyl copolymer-based membrane AN69S (Hospal, France), and SPAN, a new polyacrylonitrile-based copolymer (akzo Nobel AG). The plasma FXIIA at the membranes surface was significantly different between the membranes, while the supernatant phase FXIIA exhibited no significant differences. In contrast, activation of purified FXII in a plasma-free system with respect to supernatant activity indicated significant differences between the materials. A similar finding for the membrane-bound factor XIIA was also observed when purified factor XII was used. The membrane-bound FXIIA values observed in the plasma system containing heparin were significantly greater than in citrated plasma. This demonstrated the strong influence of heparin and the interaction of other plasma components to the membrane surface on the activation of contact phase of coagulation.
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Affiliation(s)
- B M Matata
- Bioengineering Unit, University of Strathclyde, Wolfson Centre, Glasgow, UK
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34
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Abstract
OBJECTIVES To determine the effect of pH on the cytotoxicity of mitomycin C on a wide range of established cell lines. MATERIALS AND METHODS Cultures of three human tumour cell lines, including two bladder carcinomas and one renal adenocarcinoma, and two mouse cell lines were treated with mitomycin C (concentration range 320 pM-50 microM) at a range of pH (5.8-7.8) for 2 h. The cytotoxicity of mitomycin C over this range was determined using a tetrazolium-dye-based microtitration assay. RESULTS The cytotoxicity of mitomycin C was significantly greater (confidence level > or = 95%) in acidic conditions (pH 5.8-6.0) than in neutral to alkaline pH (7.2-7.8) for three of the five cell lines. The same trend, although less marked, also occurred in the other two cell lines. CONCLUSION The cytotoxicity of mitomycin C was greater under acidic conditions for all these cell lines confirming that the activity of mitomycin C depends on pH and suggesting that the pH of the vehicle used for intravesical chemotherapy may be an important factor in the successful treatment of bladder carcinomas. The modification of pH by urine may explain some of the variation in success rates among patients treated intravesically with mitomycin C.
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Affiliation(s)
- P L Watts
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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35
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Smith MD, Grant MH, Blass CR, Courtney JM, Barbenel JC. Poly(vinyl chloride) formulations: acute toxicity to cultured human cell lines. J Biomater Sci Polym Ed 1996; 7:453-9. [PMID: 8562522 DOI: 10.1163/156856295x00454] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Two quantitative cytotoxicity assay methods (cytoplasmic retention of carboxyfluorescein and mitochondrial cleavage of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)) have been used to evaluate the response of two cultured human cell lines; HepG2 (hepatoma) and W138va13 (transformed lung fibroblasts) to extracts of a range of poly(vinyl chloride) (PVC) formulations. Two plasticizers; di(2-ethylhexyl)phthalate (DEHP) and di-isooctyl phthalate and a range of tin and non-tin stabilizers were incorporated in the study. Only those formulations containing both a plasticizer and a tin-based stabilizer produced extracts which were toxic. Extracts of those formulations which contained both plasticizer and dibutyl tin dimaleate stabilizer were toxic to both cell lines in both assay methods. Extracts of a formulation containing plasticizer and a dioctyl tin mercaptide were toxic to both cell lines in the carboxyfluorescein assay but were only toxic to the WI38va13 cells in the MTT assay. The WI38va13 cells were generally more sensitive to the extracts than the HepG2 cells. When serial dilutions of the extracts were evaluated, the carboxyfluorescein assay proved to be the more sensitive of the two. The acute toxicity of extracts of these PVC formulations cannot be directly attributed to the plasticizers or to the tin stabilizers. It is likely that a synergistic mechanism, such as plasticizer facilitated extraction of the tin stabilizer, exists.
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Affiliation(s)
- M D Smith
- Bioengineering Unit, Wolfson Centre, University of Strathclyde, Glasgow, UK
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36
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Matata BM, Wark S, Sundaram S, Courtney JM, Gaylor JD, Bowry SK, Vienken J, Lowe GD. In vitro contact phase activation with haemodialysis membranes: role of pharmaceutical agents. Biomaterials 1995; 16:1305-12. [PMID: 8573668 DOI: 10.1016/0142-9612(95)91045-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Contact phase activation was investigated in vitro using flat sheet type of haemodialysis membranes, Cuprophan (Akzo, Faser, Germany) and AN69S (Hospal, France), and a negatively charged polyamide Ultipor NR 14225 membrane as a control. The investigation focussed on the determination of factor XII-like activity (FXIIA) as an indicator of contact phase activation in the supernatant phase and at the membrane surface after plasma-membrane contact using an incubation test cell. The findings were compared with the observations from a plasma-free system utilizing purified unactivated factor XII. The plasma FXIIA bound to the membrane surface was significantly different between the membranes, while the supernatant phase FXIIA exhibited no significant differences. In contrast, the plasma-free system exhibited significant differences in the supernatant FXIIA and membrane-bound FXIIA for all the materials used and the magnitude of the activity was significantly greater for negatively charged materials. This finding demonstrated the strong influence of the interaction of other plasma constituents on the membrane surface and as such the binding and subsequent activation of factor XII may be altered possibly due to competitive binding and steric hindrance. On the addition of anticoagulants such as heparin, low-molecular-weight heparin, citrate and hirudin, no significant differences were observed in plasma supernatant phase FXIIA. However, each anticoagulant appears to have a distinct influence on the magnitude of plasma membrane-bound FXIIA. On the addition of aprotinin (a kallikrein inhibitor), no significant differences were observed in the plasma supernatant FXIIA. In contrast, aprotinin appears to significantly reduce membrane-bound FXIIA on Cuprophan and polyamide NR, but significantly increase the magnitude of the membrane-bound FXIIA on AN69S.
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Affiliation(s)
- B M Matata
- Bioengineering Unit, University of Strathclyde, Wolfson Centre, Glasgow, UK
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37
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Abstract
The investigation of blood-contacting biomaterials is an important challenge and is relevant for an improvement in the clinical application of biomaterials. With the purpose of improved clinical treatment, bioengineering viewpoints of blood-contacting biomaterials cover the material options and selection, the utilization of materials, the development of materials with better properties, and processing characteristics, and the design of relevant evaluation procedures. The bioengineering objective remains that of achieving an enhanced understanding of the relationship between a biomaterial and the biological response.
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, U.K
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38
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Mahiout A, Courtney JM. Effect of dialyser membranes on extracellular and intracellular granulocyte and monocyte activation in ex vivo pyrogen-free conditions. Biomaterials 1994; 15:969-80. [PMID: 7530999 DOI: 10.1016/0142-9612(94)90077-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study examined effects of blood-contacting materials on the monocyte reaction following the first contact of human blood with hollow fibre dialyser membranes under pyrogen-free conditions. Membrane materials were the unchanged regenerated cellulose, the synthetic polysulphone (PS), a positively charged diethylaminoethyl cellulose (DEAE-C), the negatively charged carboxymethyl cellulose (CMC) and acrylonitrile copolymer (AN). The experimental system involved perfusion with human fresh venous blood through different modules containing the materials in the form of hollow fibre membranes. Extracellular and intracellular aspects of blood reactions after the first contact with the materials were investigated in Ficoll-separated granulocytes and peripheral blood mononuclear cells. Investigations were done by release reactions of platelet activating factor (PAF), oxygen radical (O2-), leukotriene B4, prostaglandin E2 (PGE2) and cytokines (IL-1 beta, TNF-alpha, IL-6). The intracellular activation of peripheral blood mononuclear cells was done by mRNA transcription of IL-1 beta, TNF-alpha, IL-6, IL-8 and beta 2-microglobulin (beta 2-MG). From the set of parameters, release reactions were only measurable for PAF, PGE2 and O2- if a second stimulus (phorbol myristate acetate, lipopolysaccharide, zymosan and calcium ionophore) was used after blood-membrane interaction. Although the extent of the release reaction was weak, negatively charged membranes were, in general, more active. All dialysers exhibited the same increase in beta 2-MG mRNA transcription, suggesting that all blood-contacting membranes initiate the gene expression of beta 2-MG at the same level. TNF-alpha, IL-6, IL-1 beta and IL-8 mRNAs were demonstrated in the AN and CMC membranes rather than the other materials, which exhibit a lower transcription than the tubing set. As has been found, an enhanced generation of PGE2 for both CMC and AN membranes supports, therefore, the concept of an effect of the negative charges of the materials in the gene expression of cytokines. However, this initiation does not lead to the generation of cytokines, even after stimulation with pyrogens.
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Affiliation(s)
- A Mahiout
- Medical School Hanover, Department of Nephrology, Germany
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39
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Abstract
The increasing use of biomaterials in blood-contacting applications underlines the importance of an enhanced understanding of the interactions of blood with foreign surfaces. These interactions constitute a complex response involving the possible participation of proteins, platelets, the intrinsic coagulation, the fibrinolytic system, erythrocytes, leucocytes and the complement system. Interpretation of blood-biomaterial interactions and the development of improved biomaterials require the utilisation of in vitro, ex vivo or in vivo blood compatibility assessment procedures, although there is no ideal procedure for linking assessment to the potential clinical performance of a material. In clinical application, foreign surfaces represent only one of the factors influencing the blood response, with the response also influenced by the presence of antithrombotic agents, the blood condition and the nature of the application.
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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40
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Yu J, Lamba NM, Courtney JM, Whateley TL, Gaylor JD, Lowe GD, Ishihara K, Nakabayashi N. Polymeric biomaterials: influence of phosphorylcholine polar groups on protein adsorption and complement activation. Int J Artif Organs 1994; 17:499-504. [PMID: 7890439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The introduction to polymeric biomaterials of phosphorylcholine polar groups represents an approach towards the development of materials with improved blood compatibility. In this respect, two biomaterials, one a copolymer of butyl methacrylate and 2-methacryloyloxyethylphosphorylcholine (MPC), (poly(BMA-co-MPC) and the other, MPC-grafted Cuprophan, were examined with respect to their influence on protein adsorption and complement activation. Protein adsorption was studied by measurement of the adsorption of radiolabelled single proteins (albumin and fibrinogen), while complement activation was measured using radioimmunoassay for C3a des Arg. The investigation demonstrated that the polymers containing phosphorylcholine polar groups can achieve a marked reduction in protein adsorption and complement activation and supports the utilization of phosphorylcholine polar groups as a means of improving the compatibility of biomaterials for blood-contacting applications.
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Affiliation(s)
- J Yu
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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41
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Abstract
The decline in prevalence of dental caries in the western world is largely ascribed to the protective role of fluoride in water. However, in several Third World regions, its presence in excessive amounts has been detrimental to the health of resident communities due to the resulting endemic dental and skeletal fluorosis. As a prelude to introduction of preventive intervention among the affected communities, there is need to assess knowledge and perception, and affordable and effective possibilities. The results of such an assessment which was based on response of mothers from two affected communities showed that objectionable dental fluorosis was not viewed as a common health problem in the context of other more common diseases. A reawakening of interest and concern was evident when issues pertaining to oral health were addressed. Dental fluorosis was viewed as an important problem because of its unfavourable effects on an individual's personality by between 60.4 and 84.3% of the respondents. While 60% and over of the respondents attributed the problem to water, knowledge on perceived methods of prevention of fluorosis were significantly lower. Only 12% of respondents from a relatively higher income group were instituting relevant preventive strategies. Although defluoridation of water had been instituted in one area, problems relating to wrong choice of water for defluoridation to inadequate distribution of the defluoridated water were evident. Education of the communities on methods of reducing fluoride ingestion and the significance of the defluoridated water, rationalizing the distribution of defluoridated water, facilitating collection of rain water, protection of available low fluoride surface water from contamination with agro-chemicals and household defluoridation were recommended.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D L Mwaniki
- Kenya Medical Research Institute, Medical Research Centre, Nairobi
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42
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Abstract
Consideration of biomaterials for blood-contacting applications should take into account blood-biomaterial interactions, factors influencing the blood response and evaluation procedures. Examination of blood-biomaterial interactions indicates that relevant features are protein adsorption, platelet reactions, intrinsic coagulation, fibrinolytic activity, erythrocytes, leucocytes and complement activation. Factors influencing the blood response to a biomaterial in clinical application are the biomaterial structure, the presence of an antithrombotic agent, the patient status as determined by the disease and drug therapy, and the nature of the application. Evaluation options for biomaterials are clinical, in vivo, ex vivo and in vitro, with ex vivo and in vitro procedures relevant for biomaterial development.
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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43
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Abstract
There is a requirement for a convenient and reliable method for evaluating the growth rate of human keratinocytes cultured on collagen-based substrates. Therefore, three methods of determining cell growth were first used to quantify the growth rate of the well-characterised L929 mouse fibroblast cell line on tissue culture plastic and the results compared. The methods used were the measurement of total cell protein, cell counting using an electronic Coulter counter and a fluorimetric assay employing 5-carboxyfluorescein diacetate (CFDA). The CFDA assay showed the highest correlation with seeding density of the L929 cells, and the lowest standard deviations. It was the most rapid and convenient method for processing large numbers of samples. Only viable cells can deacetylate the non-fluorescent CFDA to carboxyfluorescein, which is fluorescent and accumulates inside the cells. Therefore, the assay specifically quantifies only viable cells. Subsequently, this assay has been successfully applied to the measurement of human keratinocyte growth rate on collagen gels and sponges. We have demonstrated that keratinocytes grow equally well on gels and sponges, and that media containing low calcium concentrations (0.09 mM) favour rapid proliferation of keratinocytes. Our results show that the CFDA assay is an accurate, reliable and convenient method for quantifying cell growth in vitro. It is particularly valuable when growing cells on optically opaque substrata, such as collagen sponges, where growth cannot be monitored daily by microscopy.
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Gerlach JC, Encke J, Hole O, Müller C, Courtney JM, Neuhaus P. Hepatocyte culture between three dimensionally arranged biomatrix-coated independent artificial capillary systems and sinusoidal endothelial cell co-culture compartments. Int J Artif Organs 1994; 17:301-6. [PMID: 7960199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J C Gerlach
- Chirurgische Klinik, Universitätsklinikum Rudolf Virchow, Freie Universität Berlin, Germany
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45
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Taggart DP, Sundaram S, McCartney C, Bowman A, McIntyre H, Courtney JM, Wheatley DJ. Endotoxemia, complement, and white blood cell activation in cardiac surgery: a randomized trial of laxatives and pulsatile perfusion. Ann Thorac Surg 1994; 57:376-82. [PMID: 8311599 DOI: 10.1016/0003-4975(94)91000-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Endotoxin activates complement and white blood cells and all are implicated in the pathologic effects of cardiopulmonary bypass (CPB). We investigated if reduction in intestinal bacterial load with a laxative and/or pulsatile perfusion to improve bowel circulation during CPB reduced endotoxemia and complement and white blood cell activation. Sixty patients were randomized to four groups in a 2 x 2 factorial structure: group 1 (no laxative, nonpulsatile perfusion); group 2 (laxative, nonpulsatile perfusion); group 3 (no laxative, pulsatile perfusion); and group 4 (laxative, pulsatile perfusion). Plasma concentrations of endotoxin, C3a and C5a, and granulocyte elastase (GE) were measured before anesthesia, skin incision, and heparin administration; during CPB (1, 30, 60, 90, and 120 minutes and after protamine administration); and after CPB at 3, 6, 12, 24, and 48 hours and 7 days. In all groups there was a small increase in the concentration of endotoxin (overall from 6 ng/L before CPB to 11 ng/L at 90 to 120 minutes; p < 0.001) and significant increases in C3a, C5a, and GE levels but no significant differences among the groups. Endotoxin levels did not correlate with activation of complement or white blood cells. There was a weak correlation between duration of CPB and levels of C3a (r = 0.14; p < 0.03) and GE (r = 0.25; p = 0.001) but not endotoxin or C5a. There was a general correlation between levels of C3a and GE but not in individual patients. In conclusion, CPB results in statistically significant increases in endotoxin, C3a, C5a, and GE during CPB.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D P Taggart
- Department of Cardiac Surgery, Royal Infirmary Glasgow, United Kingdom
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46
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Sundaram S, Courtney JM, Taggart DP, Tweddel AC, Martin W, McQuiston AM, Wheatley DJ, Lowe GD. Biocompatibility of cardiopulmonary bypass: influence on blood compatibility of device type, mode of blood flow and duration of application. Int J Artif Organs 1994; 17:118-28. [PMID: 8039940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The biocompatibility of artificial organs is recognised as an area presenting difficulties in terms of the complexity of the situation. The nature of the blood response involving interactions of systems, pattern and extent of change, patient status and the influence of the whole device contribute to the complexity. Recognising these, the profile of the blood response to cardiopulmonary bypass (CPB), with respect to type of device, mode of blood flow, duration of the procedure and patient status, has been evaluated by monitoring contact phase activation [Factor XII-like activity (FXIIA)], fibrinolytic activity [Fibrin degradation products (X-FDP's)], complement activation (C3a, C5a), leucocyte activation [Granulocyte elastase (GE)] and platelet and white cell imaging. FXIIA, X-FDP's, and GE rose gradually during CPB, with levels remaining elevated post-operatively for up to 48 h. In contrast, C3a levels rose sharply with no significant elevation in the post-operative period, while C5a did not show significant changes during bypass. The use of pulsatile perfusion resulted in lesser activation of the parameters, although these were significantly less only for GE. The alterations in FXIIA, X-FDP's, C3a and GE correlated positively with the duration of CPB, with this effect pronounced in the post-operative period for FXIIA, X-FDP's and GE. However, these changes had no apparent influence on clinical outcome and the majority of patients had uncomplicated post-operative recoveries. With respect to the use of bubble/membrane oxygenators, platelet and white cell deposition and the patterns of change for FXIIA and C3a were similar in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Sundaram
- Bioengineering Unit, University of Strathclyde, Glasgow, U.K
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47
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Abstract
The improved utilization of biomaterials in cardiopulmonary bypass is dependent on polymer science and technology, procedures for blood compatibility assessment, optimization of biomaterial/antithrombotic agent combinations and the interpretation of clinical data.
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Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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48
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Gerlach J, Klöppel K, Schön MR, Brombacher J, Courtney JM, Unger J, Neuhaus P. Comparison of pig hepatocyte isolation using intraoperative perfusion without warm ischemia and isolation of cells from abattoir organs after warm ischemia. Artif Organs 1993; 17:950-3. [PMID: 8110065 DOI: 10.1111/j.1525-1594.1993.tb00409.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Enzymatic hepatocyte isolation using warm ischemic pig livers from an abattoir was compared with isolation using in situ perfused organs. Using organs from animals of 30 kg body mass (BM), the intraoperative perfusion showed superior results. The use of livers from abattoir pigs of 40-50 kg BM after warm ischemia resulted in a lower yield of hepatocytes and in high rates of injured cells. The mean yield in the intraoperative perfusion group was 68 +/- 11% (wet weight), the maximum yield in the abattoir organ group was 58%. The mean viability in the intraoperative perfusion group was 65 +/- 14% (trypan blue) compared with a maximum viability of 39% in the abattoir liver group. Additional purification by density gradient centrifugation improved the viability of the abattoir liver group to a mean of 95% (trypan blue). The use of pig livers from large abattoir animals required additional purification steps to improve viability since the cell yield is considerably lower than with intraoperative organ perfusion. In general, hepatocyte isolation from abattoir organs is not recommended.
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Affiliation(s)
- J Gerlach
- Chirurgische Klinik, Universitätsklinikum Rudolf Virchow, Freie Universität Berlin, Germany
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49
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Courtney JM. Artificial organs and biomaterials. J Med Eng Technol 1993; 17:188-90; discussion 197-8. [PMID: 8151661 DOI: 10.3109/03091909309008369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J M Courtney
- Bioengineering Unit, University of Strathclyde, Glasgow, UK
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50
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Gerlach JC, Brombacher J, Courtney JM, Neuhaus P. Nonenzymatic versus enzymatic hepatocyte isolation from pig livers for larger scale investigations of liver cell perfusion systems. Int J Artif Organs 1993; 16:677-81. [PMID: 8294161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A comparison of nonenzymatic and enzymatic hepatocyte isolation was performed on pig livers. The collagenase perfusion showed superior results: mean viability 72 +/- 10% versus a maximum viability of 21% using EDTA-perfusion. A five-step collagenase perfusion technique, developed for pig livers enables larger scale investigations, in order to develop methods for hepatocyte cultures in therapeutical liver cell perfusion systems.
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Affiliation(s)
- J C Gerlach
- Chirurgische Klinik, Universitätsklinikum Rudolf Virchow, Freie Universität Berlin, Germany
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