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

Abstract

Purpose: To elucidate the role of heat shock protein-70 (HSP70) and hypoxia inducible factor-1α (HIF-1α) in diabetic retinopathy (DR) patients.

Design and methods: A comparative study was done on the serum level of both HSP70 and HIF-1α in 50 patients with type 2 diabetes mellitus (T2DM) without DR, 50 patients with T2DM and DR and 70 healthy control subjects.

Results: HSP70 and HIF-1α 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-1α increased significantly in grades 3 and 4 DR patients compared to grades 1 and 2 DR patients. A strong correlation was found between HIF-1α and the development of DR (r = 0.835, p = 0.00) but not with HSP70. HIF-1α can be used as a predictor for development of DR but not HSP70.

Conclusions: Our study was the first that investigated both HSP70 and HIF-1α 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-1α had an upper hand in the development and progression of DR. Induction of HSP70 and blockage of HIF-1α could lead to the development of novel prophylactic and therapeutic strategies for DR and potentially other diabetic complications.

Keywords: Type 2 DM; diabetic retinopathy; heat shock protein; hypoxia inducible factor 1-α.