Increased Plasma Levels of Endothelin in Diabetic Patients With Hypertension: An Alternative Viewpoint

In order to gain insight into the potential role of endothelin, a 21 amino acid peptide produced by endothelial cells, in the development of complications of diabetes mellitus, basal plasma endothelin levels were measured in 152 patients with diabetes mellitus (83 patients with type 1 diabetes mellitus, 69 patients with type 2 diabetes mellitus) and compared to those in 50 healthy controls. Blood was drawn at 8:00 AM under resting conditions and endothelin was measured after prior extraction by a sensitive radioimmunoassay specific for both endothelin 1 and 2. Endothelin levels were increased in patients with diabetes mellitus in comparison to controls. In type 1 diabetes mellitus a positive correlation between endothelin levels and age was found. We found that 60% of patients with type 1 diabetes mellitus and elevated endothelin levels higher than 2.5 pg/mL (highest value in a control person) had had diabetes for more than 20 years (P less than .05 v patients with normal endothelin levels). In type 2 diabetes mellitus the relation between elevated endothelin levels and diabetes duration was reversed. Glycosylated hemoglobin (HbA1) concentrations above 10% of total hemoglobin were measured in 62% of the patients. Arterial hypertension was present in 60% of the patients with type 1 diabetes mellitus and increased endothelin levels greater than 2.5 pg/mL (both P less than .05 v patients with normal endothelin levels).(ABSTRACT TRUNCATED AT 250 WORDS)