Impact of leptin levels upon cardiac systoloc; diastolic global myocardial and autonomic function in patients with non insulin dependent diabetes

ABSTRACT

The increased cardiovascular burden associated with diabetes mellitus [DM], is due to structural or functional abnormalities induced by DM only or by hyperinsulinemia and insulin resistance associated with metabolic disorders. Recent studies have shown that leptin increases in insulin-resistant states, such as obesity and hypertension. On the basis of evidence of plasma leptin effect on cardiovascular system, we assessed possible Impact of leptin upon cardiac function whether systolic or diastolic, also the impact upon global myocardial function assessed by a Doppler-derived myocardial performance index [Tei index] as well as cardiac autonomic function [CAN] in type 2 diabetic patients. Twenty four type 2 diabetic patients aged 51.1 +/- 7.2 years with LV functional changes defined as fasting plasma glucose >/= 126mg/dl without hypertension. Twenty four type 2 diabetic patients without LV functional changes, aged 47.6 +/- 9.0 years, were the control. ESG was performed and QTc dispersion [QTcd] was calculated for detection of CAN Ejection fraction [EF], fractional shortening [FS], E velocity, E/A ratio, isovolumetric relaxation time [IRT], isovolumetric contraction time [ICT], ejection time [ET], and the combined index of myocardial performance [Tei index = IRT + ICT/ET], were calculated by echocardiography Doppler. Fasting serum leptin and insulin were assessed. Fasting blood sugar [FBS] and glycosylated of hemoglobin [HbAlc] were also assessed. The correlations of leptin to QTcd, EF, FS, E/A ratio and Tei index were statistically analyzed. BMI, FBS, fasting serum leptin and insulin were significantly greater in the cases than in the control. QTcd, EF and FS showed non-significant difference between groups. There were statistically significant differences between groups in E/A ratio and Tei index. In the case group, leptin was significantly correlated with FBS and fasting serum inslin. Leptin was not significantly correlated with QTcd. Leptin was negatively correlated with E/A ratio and positively correlated with Tei index in the case group. It can be concluded that in conjunction with hyperglycemia, increased free fatly acids, insulin resistance and cardiac autonomic neuropathy, serum leptin is another risk factor associated with the development of diabetic cardiomyopathy