Homoarginine and blood pressure: a 10-year prospective relationship in normotensives

Nitric oxide plays a major role in the regulation of blood pressure, and impaired nitric oxide bioavailability contributes to the development of hypertension (HT). Various factors may contribute to nitric oxide bioavailability—including availability of the substrate for nitric oxide synthesis, L-arginine and its homolog L-homoarginine. We investigated whether blood pressure after 10 years associates with baseline L-homoarginine in participants who remained normotensive (NT) or developed HT, respectively. Data from the South African leg of the Prospective Urban and Rural Epidemiology study, performed in the North-West Province, were used. We investigated participants who either remained NT ( N = 166) or who developed HT ( N = 166) over 10 years. Blood pressure was measured with validated OMRON devices and serum L-homoarginine was analyzed with liquid chromatography-tandem mass spectrometry. L-homoarginine levels were similar at baseline ( p = 0.39) and follow-up ( p = 0.93) between NT and hypertensive groups. In the group that remained NT after 10 years, baseline L-homoarginine correlated positively with follow-up brachial systolic blood pressure (adj. R 2 = 0.13; β = 0.33; p = 0.001), brachial pulse pressure (adj. R 2 = 0.15 β = 0.40; p = 0.001), and central pulse pressure (adj. R 2 = 0.20; β = 0.30; p = 0.003). No significant associations were found in the group that developed HT after 10 years. We found a positive, independent association between blood pressure and L-homoarginine in a group that remained NT, but not in a group that developed HT after 10 years. This may suggest a protective role for L-homoarginine to maintain normal blood pressure, but only to a certain level. Once HT develops other factors may overshadow the protective effects of L-homoarginine.