Circulating soluble E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion molecule-1 (VCAM-1) concentrations were evaluated in 93 nonobese essential hypertensive patients, of whom 16 had impaired glucose tolerance and hyperlipidemia (group I); 25 had impaired glucose tolerance (group II); 28 had hyperlipidemia (group III); and 24 had no metabolic abnormalities (group IV). A group of 22 healthy volunteers served as a control group. All groups were without clinical or ultrasound evidence of vascular lesion and were matched for age, sex, and BMI. Endothelial soluble adhesion molecules were measured at baseline, during an oral glucose tolerance test, and after 12 weeks of either enalapril or placebo treatments. Plasma soluble E-selectin, ICAM-1, and VCAM-1 were higher (P < 0.05) in group I and II than in the other groups (group I: E-selectin, 96.1+/-27.1; ICAM-1, 304.0+/-102.1; VCAM-1, 626.1+/-156.2 microg/l. Group II: E-selectin, 88.0+/-18.0; ICAM-1, 268.0+/-84.1; VCAM-1, 594.1+/-140.9 microg/I. Group III: E-selectin, 70.1+/-18.1; ICAM-1, 195.1+/-68.0; VCAM-1, 495.9+/-110.1 microg/l. Group IV: E-selectin, 65.1+/-16.1; ICAM-1, 168.1+/-64.0; VCAM-1, 472.1+/-108.2 microg/l). Soluble adhesins levels were not higher than normal in groups III and IV. Plasma soluble ICAM-1 concentrations increased in group I after glucose administration and were directly correlated with 2-h insulin levels (r=0.648, P=0.007). Compared with placebo, 12 weeks of enalapril treatment significantly (P < 0.0001) reduced soluble E-selectin, ICAM-1, and VCAM-1. Decrements of soluble adhesins were not dependent on enalapril-related blood pressure changes. Therefore, an early endothelial activation was present in essential hypertensive patients with impaired glucose tolerance, regardless of the presence of hyperlipidemia. ACE inhibition counteracted such endothelial activation.

Our findings indicate that circulating ET-1 levels significantly increase during euglycemic hyperinsulinemic clamp in men with NIDDM. The negative correlation between total glucose uptake and circulating ET-1 levels suggests that the peptide might exert negative effects on the insulin sensitivity of target tissues. The consequent increase in insulin secretion as well as the insulin-related ET-1 release from endothelial cells could favor the development of diabetes-related vascular lesions.

Plasma endothelin-1 (ET-1) levels were studied in 15 obese hypertensive (mean age 48.5 +/- 3.9 years) and 15 obese normotensive men (mean age 49.5 +/- 3.6 years) before and after weight loss due to an 800 kcal/day diet lasting 12 weeks. Circulating peptide concentrations were also assessed in nonobese hypertensive (n = 11) and normotensive men (n = 12). Baseline plasma ET-1 levels were similar in obese hypertensive (0.87 +/- 0.22 pg/ml) and obese normotensive men (0.91 +/- 0.30 pg/ml). In seven obese hypertensive men, caloric restriction normalized blood pressure levels (systolic: from 166.6 +/- 8.1 to 145.0 +/- 6.3 mmHg, P < 0.0001; diastolic: from 106.6 +/- 5.1 to 89.1 +/- 2.0 mmHg, P < 0.0001) and decreased body mass index (BMI) (from 33.4 +/- 1.6 to 29.6 +/- 2.1 kg/m2, P < 0.002) and plasma ET-1 levels (from 0.93 +/- 0.21 to 0.64 +/- 0.26 pg/ml, P < 0.05). In the remaining obese hypertensive men (n = 8), blood pressure levels were not normalized by caloric restriction despite a significant decrease of BMI and plasma ET-1 levels (from 0.83 +/- 0.23 to 0.60 +/- 0.16 pg/ml, P < 0.04). Weight loss also significantly decreased BMI and ET-1 (from 0.91 +/- 0.30 to 0.65 +/- 0.19 pg/ml, P < 0.01) in obese normotensive men. Baseline ET-1 and fasting insulin levels were significantly correlated in obese hypertensive (r = 0.518, P < 0.05) and obese normotensive men (r = 0.535, P < 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

To evaluate the role of circulating and renal endothelin-1 (ET-1) in early diabetic nephropathy, plasma ET-1 levels and urinary ET-1 excretion were evaluated in lean, normotensive patients affected by non-insulin-dependent diabetes (NIDDM) either with (n = 9, NIDDM+) or without microalbuminuria (n = 18, NIDDM-); in never-treated, lean, essential hypertensive patients with (n = 12, EH+) or without microalbuminuria (n = 10, EH-); and in healthy volunteers (n = 12). Results showed higher plasma ET-1 levels in NIDDM+ (1.97 +/- 0.58 pg/mL) than in NIDDM- (1.59 +/- 0.14 pg/mL, P = .013), EH+ (1.40 +/- 0.21 pg/mL, P = .005), EH- (0.91 +/- 0.19 pg/mL, P < .0001), and controls (0.60 +/- 0.10 pg/mL, P < .0001). The circulating ET-1 concentration was also higher in EH+ than EH- and controls (P < .0001). Urinary ET-1 excretion did not differ (P = .387, NS) between NIDDM+ (48.5 +/- 20.1 pg/min) and NIDDM- (40.9 +/- 21.6 pg/min), but was significantly reduced (P < .0001) in both groups compared with controls (70.0 +/- 15.5 pg/min). Similar findings were observed in hypertensive subgroups. No correlations were found between urinary ET-1 and other variables, including plasma ET-1 levels, in all groups. In conclusion, NIDDM+ is accompanied by a significant increase in plasma ET-1 levels. A significant elevation of circulating ET-1 concentration was evident also in NIDDM-, suggesting that early abnormalities of ET-1 production might precede the microalbuminuric phase of diabetes-related renal damage.