Hyperthyroidism reduces the cardioprotection of subacute oral treatment with nebivolol in hearts exposed to ischemia-reperfusion: mechanisms involved

RAGONE MI; BAYLEY M; DIAZ, RG; CONSOLINI AE

Mar del Plata

Congreso; Reunión Conjunta SAIC-SAB-AAFE-AACYTAL 2023; 2023

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC) - SOCIEDAD ARGENTINA DE BIOQUIMICA(SAB) - ASOCIACION ARGENTINA DE FARMACOLOGIA EXPERIMENTAL (AAFE)- ASOCIACION ARGENTINA DE CIENCIA Y TECNOLOGIA DE ANIMALES DE LABORATORIO (AACYTAL)

The third generation beta-blocker nebivolol could be useful to preventstunning in patients suffering myocardial ischemia. However,influence of hyperthyroidism is not known. The consequences andmechanisms of subacute oral treatment with nebivolol in heartsfrom euthyroid (EuT) and hyperthyroid (HpT) rats exposed to ischemia-reperfusion were investigated. Its effects were compared withthose of subacute oral atenolol, a first-generation β1 antagonist.EuT and HpT rats were orally treated during 1 week with 20 mg/kg/day nebivolol (Neb-O), 30 mg/kg/day atenolol (Ate-O) or nottreated (C). Isolated perfused hearts were exposed to 30 min ischemiaand 45 min reperfusion (I/R) inside a flow calorimeter. Left intraventricularpressure and total heat rate (Ht) were continuouslymeasured. Maximum developed pressure (P, mmHg), diastolic pressure(LVEDP) and total muscle economy (Eco=P/Ht, mmHg.g/mW)were calculated. In EuT, Neb-O significantly increased post-ischemiccontractile recovery (PICR) (110.5±17.7% vs 19.8±4.6% ofinitial, n=5-9, p