The effect of 25- hydroxyvitamin D levels on QT interval duration and dispersion in type 2 diabetic patients

Aim To assess the relationship between corrected QT (QTc) interval and vitamin 25-hydroxyvitamin D levels (25-OHD) deficiency in type 2 diabetic patients. Methods The study included 253 patients with type 2 diabetes and 170 age-matched controls treated between October and December 2013. QTc duration and QTc dispersion were measured on ECG recordings and 25-OHD, calcium, phosphorus, and blood glucose levels were determined. Results Patients with diabetes had significantly longer QTc duration and QTc dispersion than controls (P < 0.001 and P < 0.001 respectively). Diabetic patients with prolonged QTc duration were older and had longer diabetes duration and higher HbA1c levels than patients with normal QTc interval. They significantly more frequently had 25-OHD deficiency (P < 0.001), but had similar calcium and phosphorus levels. Diabetic patients with prolonged QTc dispersion were of similar age and had similar diabetes duration and HbA1c levels as patients with normal QTc dispersion. They significantly more frequently had 25-OHD deficiency (P = 0.010), but had similar calcium and phosphorus levels. Conclusion This study showed prolonged QTc duration and QTc dispersion in patients with type 2 diabetes, especially those with 25-OHD deficiency

Plasma leptin and its relationship with lipid peroxidation and nitric oxide in obese female patients with or without hypertension

Background. Recent evidence suggested that leptin-induced oxidative stress in human endothelial cells in vivo and increased oxidative stress in human essential hypertension may further contribute to both the development of atherosclerosis and other cardiovascular diseases. We investigated the association of plasma leptin levels with plasma lipid peroxidation and nitric oxide metabolites (NOx) in obese hypertensive atherosclerosis model

Plasma total homocysteine concentrations in obese and non-obese female patients with type 2 diabetes mellitus; Its relations with plasma oxidative stress and nitric oxide levels

Hyperhomocysteinemia has been identified as independent risk factor for early atherosclerotic vascular disease. The purpose of our study was to investigate the plasma homocystein (Hcy) concentrations and its relationship with lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and nitric oxide (NOx; nitrite plus nitrate) concentrations in age-matched non-obese (n=55) and obese (n=60) female subjects with type 2 diabetes mellitus. Non-obese diabetic patients have significantly higher plasma tHcy and TBARS (p < 0.001 and p < 0.001), and significantly lower NOx concentrations than the controls (n=25) (p < 0.001). The plasma tHcy and TBARS concentrations were higher and nitric oxide concentrations were lower in obese diabetics than in non-obese diabetics (for each comparison; p < 0.001). Correlation analysis demonstrated that there was a significant positive correlation between tHcy and TBARS (r=0.452, p < 0.01) in diabetics groups. There was no significant correlation between tHcy and plasma NOx, insulin and blood pressure. We thought that Hcy might have a permissive role on the endothelium damage through free radical generating systems and the presence of obesity the free radical induced-damage has been elevated in diabetic patients

Impaired glucose tolerance: Its relevance to early endothelial dysfunction

We studied the effects of acute glycemia on plasma nitric oxide (NO; nitrite plus nitrate) levels, Cu-Zn Superoxide dismutase (Cu-Zn SOD) activity and thiobarbituric acid-reactive substances (TBARS) levels in age-matched female subjects before and tow hours after glucose loading. According to the results of glucose loading, subjects were divided in the three groups as normal (n = 13, NGT), impaired (n = 11, IGT) and diabetic glucose tolerance (n = 10, DGT). Plasma NO levels were significantly higher in subjects with DGT than in subjects with NGT (p < 0.001) and IGT (p < 0.05) at baseline. Two hours after glucose loading, plasma NO levels were significantly decreased in subjects with IGT and DGT (p < 0.001 and p < 0.001). Although plasma TBARS levels in subject with NGT did not change from the baseline levels after glucose loading, TBARS levels were significantly elevated in subjects with DGT and IGT (p < 0.001 and p < 0.001). Plasma Cu-Zn SOD activities were within a similar range in all subjects at baseline. Cu-Zn SOD activities were significantly increased in subjects with NGT, and were significantly decreased in subjects with IGT and DGT (p < 0.001 and p < 0.001) after glucose loading. There was a positive correlation between NO and glucose in subjects with NGT (r = 0.34, p < 0.01) and a negative correlation between NO and TBARS in IGT sum DGT during glucose tolerance (r= - 0.38, p < 0.01). We suggest that NO availability was decreased when the blood glucose levels were only moderately elevated above normal levels. This might be related with the enhanced oxidative stress