CIRCULATING ENDOTHELIN-1 LEVELS IN TYPE-2 DIABETIC-PATIENTS WITH ISCHEMIC-HEART-DISEASE

To investigate whether circulating endothelin-1 (Et-1) may be related to the increased incidence and severity of ischaemic heart disease in type 2 diabetes mellitus, we compared the concentrations in type 2 dia betic patients and in non-diabetic patients with coronary artery disea se (CAD) angiographically documented. Plasma levels of Et-1 were deter mined in 34 type 2 diabetic patients with CAD (16 with stable angina, 6 with unstable angina, 12 with previous myocardial infarction) and in 19 nondiabetic patients with CAD (4 with stable angina, 5 with unstab le angina, 19 with previous myocardial infarction). Fifteen diabetic p atients without CAD and 9 healthy volunteers served as control subject s. In the type 2 diabetic patients, the mean Et-1 levels were 3.19+/-1 .61 pmol/l in those with stable angina, 3.58+/-1.92 pmol/l in those wi th unstable angina, 4.24+/-2.53 pmol/l in those with myocardial infarc tion. These values were not significantly different one another, nor f rom the values obtained from type 2 diabetic controls (3.64+/-2.13 pmo l/l). In the non-diabetic patients, the mean Et-1 levels were 3.92+/-0 .73 pmol/l in those with stable angina, 4.35+/-1.67 pmol/l in those wi th unstable angina, 4.33+/-1.66 pmol/l in those with myocardial infarc tion. These values were not significantly different one another, but s ignificantly higher than those obtained from healthy controls (2.07+/- 0.67 pmol/l; P<0.001). No significant differences were found in Et-1 l evels between diabetic and non-diabetic patients with stable, unstable angina and previous myocardial infarction. In contrast. a statistical ly significant difference was found in Et-1 levels between diabetic an d non-diabetic control subjects (P<0.05), In conclusion, similar raise d concentrations of Et-1 in diabetic and cion-diabetic patients with s table, unstable angina and previous myocardial infarction do nor suppo rt the hypothesis that higher levels of Et-1 in diabetic patients are responsible for the increased incidence of CAD in diabetes mellitus. H owever, the raised Et-1 levels found in diabetic patients in the absen ce of CAD strongly suggest that a generalised endothelial dysfunction, documented in our study by increased levels of Et-1, most probably pr ecedes subsequent cardiovascular diseases.