Urinary Endothelin-1 as a potential non-invasive biomarker for young hypertensive adults

INTRODUCTION: The increasing burden of hypertension among young adults is alarming, given that cardiovascular risk begins as early as the prehypertensive stage. Hence, identifying potential protein biomarkers associated with early blood pressure (BP) elevation is essential for improving risk stratification and enabling timely intervention. Plasma endothelin-1 (ET-1) has been shown to be implicated in the early development of hypertension; however, the role of urinary ET-1 remains underexplored. The less invasive nature of urine sampling compared to blood collection could enhance compliance in hypertension screening efforts among the young population. OBJECTIVE: To investigate the concentration of urinary ET-1 in young prehypertensive and hypertensive adults. MATERIALS & METHODS: This was a comparative cross-sectional study recruiting a total of 72 participants aged 18 to 45 years, comprising 24 normotensive, 25 prehypertensive, and 23 newly diagnosed hypertensive individuals. Urine and blood samples were collected, and ET-1 concentrations were quantified using enzyme-linked immunosorbent assay (ELISA). RESULTS: Urinary ET-1 concentrations demonstrated a decreasing trend across normotensive, prehypertensive, and hypertensive groups (median [interquartile range]: 3.84 [7.05] vs 2.12 [2.04] vs 1.37 [5.01] pg/mL), with significantly lower levels in the hypertensive group compared to the normotensive group (p = 0.035). There was no significant association between urinary ET-1 and elevated blood pressure following adjustment for established cardiovascular risk factors. There was also no significant correlation between plasma and urinary ET-1 levels. CONCLUSION: The significantly lower urinary ET-1 levels observed in the hypertensive group suggest that diminished renal ET-1 production may contribute to the early pathophysiology of young-onset hypertension. Renally synthesised ET-1, which is essential in the regulation of sodium and water excretion, may serve as a promising non-invasive biomarker for the early detection of hypertension in young cohort. Further research is warranted to validate its association with elevated BP in larger and more diverse cohorts.