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Title: Analysis of aldehyde detoxification mechanisms and the effects of a novel aldehyde scavenging drug in experimental diabetic retinopathy
Author: McDowell, Rosemary Eleanor
ISNI:       0000 0004 5915 7678
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2015
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Recent studies have identified that retinal Muller cells accumulate the acrolein (ACR)-derived protein adduct FDP-lyslne during diabetes. The phenomenon has been linked with the dysfunction of these calls in the early stages of diabetic retinopathy. The current project investigates the processes underlying the accumulation of FOP-lysine In Muller cells during diabetes, and strategies for preventing Its accumulation and related pathology. RT-PCR was used to Identify the enzymes capable of detoxifying ACR that were expressed In the rat retina. Immunohistochemistry (IHC) experiments Idenified that ALDH and AKR enzymes ALDH1a1, ALDH2, AKR1b1 and AKR7a2 are preferentially localised In retinal Muller cells. RT-qPCR experiments identified that Important aldehyde dehydrogenase (ALOH) and aldo-keto reductase (AKR) enzymes were down regulated in the diabetic retina, The effect of diabetes on ALDH and AKR gene expression was also investigated in lens, cornea and kidney. The down-regulation of mRNA transcript expression, however, appeared to be confined to the retina. The effect of diabetes on the gene transcript expression of enzymes Involved In polyamine metabolism was also investigated, but no difference In expression was observed. The results of western blotting experiments on ALDH and AKR enzymes, comparing diabetic whole retina with control, were In agreement with the RT-qPCR data and Indicated that ALDH1a1 and AKR7a2 were down-regulated in protein extracted from whole retina. Semi-quantitative analysis of IHC experiments using control and diabetic rat retina demonstrated down-regulation of ALOH1a1 in diabetic Muller cells. An ALDH enzyme activity assay using control and diabetic whole retinal lysetes, lent further support to the conclusion that detoxification of ACR is impaired in the diabetic retina. 2-hydrazino-4,6-dlmethyl pyramidine (2·HDP) was identified in ELISA experiments to be a potent scavenger of ACR, preventing the formation of its adducts. The compound was also capable of preventing ACR mediated cell death In a Muller cell-derived cell line. When 2-HDP was administered to diabetic rats it significantly reduced the accumulation of FDP-lysine in Muller cells. The effect was associated with normallsatilon of the electroretinogram and potassium channel distribution, and a reduction in the mRNA expression of reactive and inflammatory markers In Muller cells of diabetic animals.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available