NHE-1 hyperactivity correlates with ABPM in patients without cardiac hypertrophy (CH): a new strategy to early identify subjects with higher risk of CH?

ESPECHE W; VILLA-ABRILLE MC; MARCH C ; ZAVALA MR; ENNIS IL,; DE IRAOLA A; LEIVA C; SALAZAR MG; LEIVA CE; COR S; STAVILE N; ESPECHE W; VILLA-ABRILLE MC; MARCH C ; ZAVALA MR; ENNIS IL,; DE IRAOLA A; LEIVA C; LEIVA CE; SALAZAR MG; COR S; STAVILE N

Mendoza

Congreso; XXIV Congreso Argentino de Hipertensión Arterial - XXIV Reunión Científica la ISHR Latin American Section; 2017

Myocardial Na+/H+ exchanger-1 (NHE-1) hyperactivity plays a crucial role in pathological cardiac hypertrophy (PCH) and the progression to heart failure. Moreover, NHE-1 is hyperactive in blood cells from hypertensive compare to non-hypertensive individuals. Myocardial stretch due to the hemodynamic overload would induce NHE-1 hyperactivity. Since PCH could precede the diagnosis of hypertension, at least by office based estimations of blood pressure (BP), we aim to determine whether NHE-1 activity could be an early indicator of increased risk of PCH in subjects with normal or slightly elevated BP. Platelet NHE-1 activity, ambulatory BP monitoring (ABPM) and office base BP were recorded in 38 non diabetic subjects without evidence of target organ dam-age and not taking antihypertensive drugs (18 men, 48±12 years old, BMI 28.9±5.4 Kg/m2, office BP 133±12/ 82±9 mmHg). One patient with PCH diagnosed by echocardiography was excluded. NHE-1 activity (initial rate of pHi recovery from induced intracellular acidosis) was higher in the upper tercile of mean BP estimated by ABPM (p=0.018). However, this relationship was not evident when office-based mean BP was used (p=0.827). Interestingly, NHE-1 activity increased abruptly with mean BP by ABPM > 100 mmHg. Even though mean BP from office-based measurements correlated with ABPM values (rho = 0,394, p = 0.017), NHE-1 activity only significantly correlated with the latter (rho = 0,338, p 0.041) but not with the former (rho = 0.180, p = 0.294). In conclusion, there is a significant correlation between platelet NHE1 activity and mean BP only when it is estimated by ABPM. Office-based BP categories seem not to adequately represent the hemodynamic load at which the heart is exposed. Therefore, NHE-1 activity, especially in the subgroup of subjects with pre-hypertension hypertension stage I, emerges as a promising diagnostic tool to help identify patients with higher risk of target organ damage, i.e. PCH.