Glucose-mediated regulation of transforming growth factor-beta (TGF-β) and TGF-β receptors in human retinal endothelial cells

Author： Pascal Monique M. Forrester John V. Knott Rachel M.

Publisher： Informa Healthcare

ISSN： 0271-3683

Source： Current Eye Research, Vol.19, Iss.2, 1999-08, pp. : 162-170

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Abstract

PURPOSE. Diabetic retinopathy is a micro-angiopathy affecting predominantly small vessels of the retina. Clinical trials have demonstrated a strong association between tight glucose control and a reduction in the incidence and the severity of diabetic retinopathy. Transforming growth factor beta (TGF-β) is involved in the control of endothelial cell proliferation, adhesion, and deposition of extracellular matrix, thus TGF-β may play a role in the control of endothelial cell proliferation seen in the disease. We wished to investigate the regulation of transforming growth factor beta and its receptors (type I and II) in human retinal endothelial cells exposed to a range of glucose concentrations. METHODS. Human retinal endothelial cells were isolated from donor eyes, cultured in vitro and exposed to a range of glucose concentrations (0–25 mmol/l). TGF-β protein and mRNA levels were determined by ELISA and Northern analysis, respectively. The binding affinities and TGF-β receptor numbers were defined using a binding assay. RESULTS. Northern hybridisation and ELISA showed that after 8 hours, the level of TGF-β mRNA and protein was significantly higher at 15mmol/l compared to 5, 20 or 25mmol/ l. Binding assays showed that for high glucose (25 mmol/l), human retinal endothelial cells express a population of TGF-β receptors with higher affinity for its ligand than at 5 or 15 mmol/l. CONCLUSIONS. These results demonstrate that glucose regulates TGF-β mRNA and protein production and also TGF-β receptor expression in human retinal endothelial cells. Thus, the glucose-mediated changes that occur in diabetic patients may expose human retinal endothelial cells to potential angiogenic factors which may influence disease progression.