Heat shock protein-70 and hypoxia inducible factor-1 in type 2 diabetes mellitus patients complicated with retinopathy

PurposeTo elucidate the role of heat shock protein-70 (HSP70) and hypoxia inducible factor-1 (HIF-1) in diabetic retinopathy (DR) patients. Design and methodsA comparative study was done on the serum level ofboth HSP70 and HIF-1 in 50 patients with type 2 diabetes mellitus (T2DM) without DR, 50 patients with T2DM and DR and 70 healthy control subjects. ResultsHSP70 and HIF-1 were significantly increased in T2DM patients compared to controls and increased in patients with T2DM & DR compared to T2DM patients without DR (p<0.0001). HSP70 did not differ among the patients with different stages of DR, while HIF-1 increased significantly in grades 3 and 4 DR patients compared to grades 1 and 2 DR patients. A strong correlation was found between HIF-1 and the development of DR (r=0.835, p=0.00) but not with HSP70. HIF-1 can be used as a predictor for development of DR but not HSP70. ConclusionsOur study was the first that investigated both HSP70 and HIF-1 in humans and was the first that measured their levels in serum of patients with DR. The study suggested that HSP70 might have a protective function in T2DM patients rather than a therapeutic function. HIF-1 had an upper hand in the development and progression of DR. Induction of HSP70 and blockage of HIF-1 could lead to the development of novel prophylactic and therapeutic strategies for DR and potentially other diabetic complications.