Introduction: Endothelial dysfunction is implicated in the pathogenesis of metabolic syndrome and diabetic complications. Endothelin-1 is a potent endothelium-derived vasoconstrictive factor.
Objectives: However, an association between endothelin-1 production and obesity in diabetic patients remains not fully understood. Therefore, the aim of the study was to investigate serum levels of endothelin-1 in obese and non-obese patients with type 2 diabetes.
Methods:
We studied 48 patients with type 2 diabetes -24 with obesity (age: 56.8 Β± 2.2 years, BMI: 35.3 Β± 0.8 kg/m 2 ; waist/hip ratio [WHR]: 0.98 Β± 0.03; data everywhere are presented as mean Β± SEM), 24 patients without obesity (age: 52.1 Β± 1.6 years, BMI: 24.2 Β± 0.8 kg/m 2 ; WHR: 0.88 Β± 0.02), and 40 non-diabetic subjects -20 obese (age: 52.8 Β± 2.1 years, BMI: 33.9 Β± 0.6 kg/m 2 ; WHR: 0.89 Β± 0.02), and 20 non-obese (age: 47.4 Β± 1.4 years, BMI: 24.0 Β± 0.6 kg/m 2 ; WHR: 0.84 Β± 0.02). Serum endothelin-1 levels were determined by immunoenzyme assay. Statistical analysis was performed by Student's paired and Pearson's correlation tests.
Results:
We found a significant increase of serum endothelin-1 levels in obese patients with diabetes compared to obese non-diabetic subjects -8.09 Β± 0.51 vs 5.8 Β± 0.45 pmol/L, respectively, P < 0.001. Endothelin-1 levels were also higher in non-obese patients with diabetes compared to control non-obese subjects without diabetes -6.67 Β± 0.38 and 4.38 Β± 0.31 pmol/L, respectively, P < 0.05. Moreover, there was a significant elevation of serum endothelin-1 levels in those with obesity compared to non-obese subjects either in people with or without diabetes mellitus. In patients with diabetes there was a significant correlation between fasting glucose, BMI, and endothelin-1 levels (r = 0.51, P < 0.05 and r = 0.68, P < 0.05, respectively).
Conclusions:
The revealed changes of endothelin-1 serum levels could reflect an endothelial dysfunction in type 2 diabetic patients, which is the most pronounced in those with obesity. Hyperglycemia and obesity appear to be significant factors contributing to elevation of endothelin-1 production in patients with diabetes.