Endothelial Dysfunction in Patients with Noncomplicated and Complicated Hypertension

Abstract

Endothelial dysfunction plays an important role in the pathogenesis of hypertension. Other risk factors of atherosclerosis also affect its development. The aim of the study was to assess nitric oxide metabolites concentration (nitrites and nitrates No_x) and endothelin (ET-1) in plasma and cyclic 3,5-guanosine monophosphate (cGMP) in 24 h-urine collection in patients with noncomplicated hypertension without risk factors of atherosclerosis and in hypertensive patients with coronary artery disease (CAD). Sixty-eight subjects were included in the study (44 men, 24 women), aged 47 ± 76 years, allotted into four groups: I – controls (18 clinically healthy subjects); II – 12 subjects with hypertension without risk factors of atherosclerosis; III – 16 subjects with hypertension and risk factors of atherosclerosis; and IV – 22 subjects with hypertension and CAD. Plasma NO_x concentration was determined using the Greiss method, plasma ET-1 by ELISA, and urine cGMP using the immunoenzymatic method. Plasma NO_x concentration was 14.00 ± 6.88 μmol/L in group I, in group II – 18.62 ± 5.84 μmol, in group III – 9.96 ± 4.72 μmol/L, and in group IV – 8.78 ± 3.72 μmol/L. Statistically significant differences were between groups I and III (p < 0.05) and I and IV (p < 0.04) and groups II and III (p < 0.01) and II and IV (p < 0.01). The concentration of cGMP in 24 h urine collection was in group I – 40 ± 24 pmol/L; in group II – 54 ± 41 pmol/L; in group III – 38 ± 32 pmol/L; and in group IV – 42 ± 36 pmol/L. There were no significant differences between the groups. Plasma ET-1 concentration was 3.86 ± 0.52 pg/mL in group I, in group II – 4.05 ± 0.71 pg/mL, in group III – 4.22 ± 0.79 pg/mL and in group IV – 4.38 ± 0.75 pg/mL. Statistically significant differences were between group I and III (p < 0.05), I and IV (p < 0.03), and between group II and IV (p < 0.04). Endothelial dysfunction was not found in hypertensive patients without a family history of cardiovascular diseases and without other risk factors of atherosclerosis. Deterioration of endothelial function was observed in patients with hypertension with risk factors of atherosclerosis. It was most pronounced in those with CAD.

Keywords:

• hypertension
• endothelial dysfunction
• nitrite and nitrate
• endothelin-1
• cGMP