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Title: Restoration of the Glomerular endothelial glycocalyx as a novel mechanism for improving function in diabetes
Author: Desideri, Sara
ISNI:       0000 0004 6057 7477
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2016
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AIM: Endothelial glycocalyx (eGLX), the inner lining of glomerular capillaries, regulates glomerular albumin permselectivity and is damaged in diabetes. Recently, it has been shown that the eGLX can be modified and repaired by different substances, in particular angiopoietinl (Angl) and hydrocortisone. We hypothesise that direct restoration of eGLX in the glomerulus will improve glomerular permeability in diabetes. To be able to test this hypothesis Angl and hydrocortisone were tested in vitro, then the best candidate was chosen for further ex vivo studies. To be able to test this compound ex vivo I also designed, characterised and validated a new albumin permeability assay based on quantitative fluorescence confocal microscopy. RESULTS: Angl was found to induce the most significant eGLX changes in vitro. Angl increased the expression of surface glycosaminoglycans (GAG) and significantly increased their release into the media of human conditionally immortalised glomerular endothelial cells (ciGEnC) in culture at different time points. Using ion exclusion chromatography, . Angl significantly increased hyaluronan (HA) synthesis/turnover within Ih of treatment and also increased hyaluronan synthase 2 (HAS2) mRNA expression. Together, this suggests that Angl may modify the eGLX by inducing hyaluronan synthesis via HAS2. A novel glomerular permeability assay was validated and calibrated. There was a significant increase in albumin permeability (Ps'alb) between glomeruli isolated from diabetic rats compared to sham and a significant decrease in Ps'alb in diabetic glomeruli treated with Angl. Quantitative electron microscopy demonstrated that Angl was able to restore the eGLX within the intact glomerular filtration barrier within 30min. CONCLUSION: Modifying eGLX using Angl may provide a new approach to enhance vascular integrity and, in particular, to restore the eGLX in early diabetic stages. The major advantage of our glomerular albumin permeability assay is that the study of a single glomerulus offers the opportunity to examine the influence of different agents on a single glomerular capillary loop, which can be applied to human glomeruli.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available