Plasma Endothelin-1, Homocysteine, and Nitric Oxide Levels in a Multiethnic Hypertensive Cohort from the United Arab Emirates

Background : Hypertension is a major cause of morbidity and mortality in the United Arab Emirates (UAE). However, little is known regarding vasoactive biomarkers and lipid profiles in hypertensives versus normotensives in this heterogeneous ethnic population. Aims: This study aimed to evaluate plasma endothelin-1 (ET-1), homocysteine (Hcy), nitric oxide (NO), and lipid parameters among hypertensive subjects and normotensives controls in a heterogeneous ethnic population from the UAE. Methods: We collected venous samples from 164 hypertensive and 112 normotensive subjects matched for age, gender and ethnicity to determine their plasma levels of ET-1, Hcy and NO as well as their lipid profile. Results: Hypertensive subjects displayed significantly higher plasma levels of ET-1 (p < 0.001) and NO (p < 0.001) but lower insulin levels (P<0.006) than normotensives. In contrast, there was no statistically significant difference with regard to Hcy concentrations. Very low-density lipoprotein (VLDL) and triglycerides (TG) levels were significantly (p < 0.01) higher in hypertensives than controls. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and non-esterified fatty acids (NEFA) were significantly lower (p < 0.01) in hypertensives than normotensives. Conclusion: In our heterogeneous ethnic population, levels of ET-1 and NO, but not of Hcy, were found to be associated with hypertension and may possibly contribute to an increased systemic vascular resistance among hypertensives. Whether the elevated ET-1 results are because of overproduction or decreased clearance remains to be ascertained Elevated levels of TG and VLDL, alongside with unaltered TC levels, seem to indicate the presence of type IV hypertriglyceridaemia.