Role of serum nitrogen oxide in treated hypertensive and normotensive subjects

Abstract

Background: Hypertension is a leading cause of mortality and morbidity worldwide. Essential hypertension is characterized by endothelial dysfunction and increased vascular tone and resistance. The former is the result of imbalance of endothelium derived contracting & relaxing factors. Nitric oxide which is produced locally by endothelium is crucial for maintaining vascular tone. Aims & Objectives: To study the role of nitric oxide in hypertensive cases and also find out the normal level of serum nitric oxide in the specific population of the district East Godavari, Andhra Pradesh. Materials M (Male: Female =1.3:1) was taken for the study. Serum creatinine was measured and hypertensives having elevated serum creatinine (>0.3 mg/dl) were excluded from the study; this was done to rule out any effect of kidney functional status on level of serum nitric oxide. Serum nitrate was measured using colorimetric Griess assay. The data was analyzed using SAS 9.1 Results: The mean serum nitrate in hypertensive patients (43.77± 0.29 μmol /L) is higher than the controls (38.57 ±5.02 μmol /L) and is statistically significant p< 0.0002. The concentration of nitrogen oxide (nitrate plus nitrite) in the plasma of systemic venous blood was significantly more in the hypertension group than in the control group. The plasma nitrogen oxide concentration showed a significant positive correlation with both systolic (r=+1.57, p<0.05) and diastolic blood pressure (r=+1.47, p<0.05). Conclusion: Elevated serum nitric oxide level in hypertensives indicates an endothelial cell response to the antihypertensive medications. Serum nitric oxide thus may be used as a marker for predicting “future hypertensive”. This may allow the physicians to modulate life style of these “future hypertensive” before overt hypertension actually develops; this will not only save a probable future hypertensive from taking many medications and facing complications but will also reduce the burden of this ever-growing devastating disease. Also the mean serum nitrate in controls of this study is much different from the other studies; does it indicate that serum nitric oxide value is population specific? Anyway, the authors feel that in order to establish both these points and comment with such conviction, much larger future studies are needed.