Endothelial dysfunction, nitric oxide and platelet activation in hypertensive and diabetic type II patients

Alterations in the synthesis or enhanced inactivation of nitric oxide (NO) and an increase in endothelin-1 production lead to an imbalance that can induce arterial hypertension. Type II diabetes is characterized by impaired endothelium-dependent vasodilation and vascular disease. NO is produced through L-arginine pathway by three different isoforms of nitric oxide synthase (NOS), an inducible form that can be activated by cytokines such as tumor necrosis factor alpha (TNFalpha). We evaluated NO plasmatic levels, endothelial damage markers such as von Willebrand factor (vWF), platelet activation, soluble P-selectin (sP-Sel), TNFalpha levels, insulinaemia (I), glycosylated haemoglobin (HbA1c), glycaemia and blood pressure in 32 hypertensive diabetic type II patients (Group A), 37 hypertensive patients (Group B) and 35 healthy subjects (Group C) matched in sex, age, body mass index and dietary habits. The level of I was increased in patients compared to the controls and correlated with their NO levels. vWF plasmatic levels were increased in Group A compared to Groups B and C. We also found significant differences in platelet activation among all the groups. In diabetic patients, increased NO levels correlated with TNFalpha, HbA1c and platelet activation showed greater endothelial damage than in Group B. These parameters described a prothrombotic state associated with an insulin resistance state, an increased vWF release, raised sP-Sel and TNFalpha levels and, maybe, low NO bioavailability, which could lead to a higher risk of development of thrombotic events in hypertensive diabetic patients (Group A) than in the hypertensive patients in Group B.