Cardioprotective role of IGF-1 in the hypertrophied myocardium of the spontaneously hypertensive rats: A key effect on NHE-1 activity

BURGOS, JUAN IGNACIO; YEVES, ALEJANDRA; MEDINA, ANDRÉS; ENNIS, IRENE

Sønderborg

Simposio; ACTA PHYSIOLOGICA INTERNATIONAL SYMPOSIUM 49TH SANDBJERG MEETING ON MEMBRANE TRANSPORT; 2017

Acta Physiologica

Aim: Myocardial Na+/H+ exchanger-1 (NHE-1) hyperactivity and oxidative stress are interrelated phenomena playing pivotal roles in pathological cardiac hypertrophy development and progression to heart failure. Exercise training is effective to convert pathological into physiological hypertrophy in the spontaneously hypertensive rats (SHR) and IGF-1 ?humoral mediator of exercise training- inhibits myocardial NHE-1, at least in normotensive rats. On the other hand, exercise training has been proposed to have an antioxidant effect. Therefore, we hypothesize that IGF-1 by hampering NHE-1 hyperactivity and oxidative stress could be responsible for the cardioprotective effect of training in the SHR. Methods: NHE-1 activity [proton efflux (JH+) mmol/L/min], H2O2 production, superoxide dismutase (SOD) activity and contractility were measured in SHR cardiomyocytes. Results: IGF-1 significantly decreased NHE-1 activity (JH+ at pHi 6.9: 1.98±0.38, n=8 vs. C 3.76±0.53, n=19, p