Elevated levels of heat-shock protein 70 (HSP70) in the mononuclear cells of patients with non-insulin-dependent diabetes mellitus.

Increased free radicals and reduced levels of antioxidants have been reported in diabetes mellitus. Since heat-shock protein 70 (HSP70) is a stress-induced protein and is suggested to play a protective role against oxidative stress, we have investigated whether HSP7O acts as one of the defense systems against this stress. We separated mononuclear cells from diabetic patients (N=12) and age- and sex-matched healthy controls (N =12), and detected HSP70 by western blot analysis. The results were expressed by the ratio of the density determined by laser densitometry, to that of 10 mu g of purified HSP70. HSP70 levels in the mononuclear cells of diabetic patients (0.78 + or- 0.56) were significantly high, compared with healthy subjects (0.43 + or - 0.23) (P < 0.05). No correlation was found between HSP7O and hemoglobin A1c, fasting plasma glucose, duration of diabetes or diabetic complications except age. A negative correlation was found between HSP70 and age (r = -0.658, P < 0.05). These results suggest that HSP70 levels in the mononuclear cells are elevated reflecting increased oxidative stress in patients with diabetes.