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Background: The alteration of endothelin (ET) levels in diabetic patients with cardiac autonomic neuropathy (CAN) has not been studied extensively and its correlation with cardiac function parameters has not been discussed., Hypothesis: The aim of the present study was to discuss the correlation between the degree of cardiac autonomic neuropathy, plasma big-ET levels, and cardiac functions in diabetic patients who were clinically free of cardiovascular disease., Methods: Twenty subjects (32.1 +/- 7.8 years, 11 men, 9 women) with insulin-dependent diabetes mellitus (IDDM) were studied to evaluate the relationship between circulating big-endothelin (big-ET1) levels, CAN, and cardiac functions. The severity of CAN was scored according to Ewing's criteria. Cardiac functions were assessed using Doppler echocardiography., Results: Left ventricular systolic function in the patient group was within normal limits and comparable with the values of the control group (n = 10). The mean E/A values of diabetics with CAN (1.15 +/- 0.33, p = 0.004) and without CAN (1.34 +/- 0.17) were significantly lower than those of controls (1.57 +/- 0.27). Diabetics with CAN had significantly higher big-ET1 values (81.1 +/- 94 pg/ml) compared with others (12.4 +/- 5.9 and 21.1 +/- 17.7 pg/ml, p = 0.04). Circulating big-ET1 levels showed a significant correlation with E/A values in the control group (p = 0.01, r = -0.7) and with peak A values (p = 0.003, r = 0.64) in diabetics. The CAN score correlated negatively with E/A values (p = 0.01, r = 0.54)., Conclusions: High big-ET levels might have an important role in the pathogenesis or consequences of diastolic dysfunction in diabetics with CAN. Their role in cardiac autonomic neuropathy and diastolic dysfunction should be investigated further.

To evaluate the behavior of circulating endothelin and atrial natriuretic peptide (ANP) during coronary artery bypass graft (CABG) surgery, blood samples from patients with coronary artery disease (n = 8) were investigated before, during and after operation. Plasma levels of endothelin and ANP were determined using the radioimmunoassay method. Baseline plasma levels were compared to those of normal volunteers (n = 6). Left ventricular function at rest and as a response to isometric exercise was evaluated using radionuclide ventriculography before and after coronary bypass surgery. The mean endothelin value was found to be within normal limits, however the mean ANP value was slightly higher than control. Patients had significantly improved left ventricular systolic and diastolic function after surgery. The mean endothelin level was higher than initial values immediately after extra-corporeal circulation and returned to initial values in two hours. However, ANP values were increased and remained higher than initial values. Baseline endothelin values were negatively correlated with systolic function parameters, whereas endothelin and heart rate had a positive correlation before extra-corporeal circulation. Coronary artery bypass graft surgery may cause an increase in the circulating endothelin level either due to endothelial injury or due to myocardial ischemia and hypothermia. Following surgery, increased endothelin levels returned to normal values immediately.

Plasma levels of atrial natriuretic peptide (ANP) and of endothelin (ET) were significantly elevated (87.7 +/- 13.9 pg/ml and 79.7 +/- 10.8pg/ml, respectively) during the acute phase of acute poststreptococcal glomerulonephritis (APSGN). Plasma renin levels were normal, fractional excretion of sodium (FENa) was 0.5 +/- 0.1% and creatinine clearance (CCr) averaged 82.2 +/- 18.3 ml/min per 1.73 m2. In the recovery phase of the disease (n = 12), levels of ANP (23.6 +/- 6.7 pg/ml) and ET (43.1 +/- 2.4 pg/ml) fell and were not significantly different from those measured in 11 control subjects. FENa increased to 1.3 +/- 0.1% and CCr to 113.5 +/- 12.1 ml/min per 1.73 m2 (all values mean +/- standard error). ANP did not correlate with PRA, blood pressure, CCr or FENa. There was an inverse relationship between the ET level and FENa in the acute phase of the disease (r = 0.489, P < 0.05), but no significant correlation between ET and blood pressure, PRA, CCr or ANP was found. We suggest that, despite the sodium retention, the increased ANP level in APSGN indicates unresponsiveness of the kidneys to ANP; the increased ET levels may contribute to this.