Increased serum HSP70 levels are associated with the duration of diabetes.

The evolutionary conserved family of heat shock proteins (HSP) is responsible for protecting cells against different types of stress, including oxidative stress. Although the levels of HSPs can be readily measured in blood serum, the levels of HSP70 in patients with different durations of diabetes have not been studied before. We quantified serum HSP70 levels in a healthy control group (n = 36) and two groups of type 2 diabetic patients, defined as newly diagnosed diabetes (n = 36) and patients with diabetes duration of more than 5 years (n = 37). The clinical characteristics and biochemical parameters were evaluated in the studied population. We found that serum HSP70 levels were significantly higher in patients with diabetes when compared with controls (p < 0.001) and it was higher in patients with disease for more than 5 years than in newly diagnosed patients (p < 0.001). Serum HSP70 was inversely correlated with fasting blood sugar in patients with diabetes for more than 5 years (r = -0.500, p = 0.002), positively correlated with the history of hypertension in newly diagnosed patients (p < 0.001), and positively correlated with age in patients with diabetes (r = 0.531, p = 0.001). Serum level of HSP70 is significantly higher in patients with diabetes and correlates with the duration of disease. Higher HSP70 in prolonged diabetes versus newly diagnosed diabetes may be an indicator of metabolic derangement in the course of diabetes.

Serum oxidized-LDL is associated with diabetes duration independent of maintaining optimized levels of LDL-cholesterol.

Oxidized low-density lipoprotein (ox-LDL) plays a key role in the progression of atherosclerosis and diabetes complications. The aim of this study was first, to evaluate the association between ox-LDL and diabetes duration, and second, to examine serum level of ox-LDL in patients with prolonged diabetes and a desirable LDL-cholesterol level. A total of 36 type-2 diabetic patients with a diabetes duration of more than 5 years, 36 newly diagnosed diabetic patients, and 36 age-, sex- and BMI-matched healthy participants were recruited. Healthy participants and newly diagnosed patients were not receiving any treatment. All patients with prolonged diabetes had desirable LDL-cholesterol levels (<100 mg/dL), according to the adult treatment panel-III guidelines. While LDL-cholesterol was significantly lower in patients with diabetes duration >5 years, in comparison to newly diagnosed patients (P < 0.01), ox-LDL was significantly higher in patients with prolonged diabetes (P < 0.001). The ox-LDL-to-LDL ratio was dramatically higher in patients with diabetes duration >5 years in comparison to newly diagnosed patients and healthy participants (P < 0.001). Ox-LDL was significantly associated with diabetes duration (r = 0.519, P = 0.001). In multivariate analysis, this association remained significant (beta = 0.501, P = 0.003) after adjustment for potential confounders. In conclusion, this study showed that the serum ox-LDL level increases with the length of diabetes, even though the patients' LDL-cholesterol level is maintained at a desirable level. Our findings highlight that possibly more attention should be focused on markers of oxidative stress in the management of lipids in diabetic patients.