Triiodothyronine improves post-ischemic myocardium recovery: A response associated with enhanced AMP-activated protein kinase activation.

ROMINA HERMANN; MAILÉN FLORENCIA CÓRDOBA; ANDREA FELLET; FEDERICO JOAQUÍN REZNIK; DÉBORA ELISABET VÉLEZ; MARÍA DE LAS MERCEDES FERNÁNDEZ PAZOS; VICTORIA MESTRE CORDERO; MARÍA GABRIELA MARINA PRENDES

La Havana

Congreso; II Pan American Congress of Physiological Sciences; 2019

Low triiodothyronine (T3) syndrome is the most frequent alteration of thyroid hormone metabolism in acute myocardial infarction, which occurs immediately after the onset of symptoms. Although low T3 state has been interpreted as a merely adaptive mechanism, the experimental and clinical data have rebutted this hypothesis, suggesting that T3 might play an effective role in the cardioprotection against ischemia-reperfusion injury. Recent studies have provided evidence that T3 could enhance the recovery of ischemic myocardium through the preservation of mitochondrial function and the improvement of energy substrate metabolism. To this respect, it has been suggested that T3 could activate AMP-activated protein kinase (AMPK), the cellular ?fuel gauge? enzyme, which in previous studies carried out in our laboratory exerted protective effects for the recovery of ischemic-reperfused myocardium.The aim of the present study was to investigate the effects produced by the acute treatment with T3 and the pharmacological inhibition of AMPK by Compound C (CC), on isolated rat left atria subjected to 75 min simulated ischemia- 75 min reperfusion (Is-Rs).For this aim, atria were incubated in Krebs?Ringer containing 10 mM glucose, 95% O2?5% CO2, pH 7,4. For Is, the incubation medium contained 10 mM 2-deoxy-D-glucose, 95% N2?5% CO2, pH 6.8. T3 (60 nM) and CC (10 M) were added to the bathingmedium at the onset of Is and maintained throughout the experiment. ANOVA, followed by Tukey?s test, was used, n=8/group.Results showed that T3 increased AMPK activation during Is, which was prevented by CC (End stabilization period (ESP): 1.33±0.02, Is-Rs: 2.20±0.11*, Is-Rs+T3:2.79±0.10*#, Is-Rs+CC: 1.08±0.19, Is-Rs+T3+CC: 1.17±0.10 AU; *p