RESUMEN
BACKGROUND/AIMS: The simultaneous supplementation of creatine and D-ribose has been shown to reduce apoptosis in vitro in non-irreversibly injured cultured ischemic cardiomyocytes through down-regulation of the signaling mechanisms governing adenosine monophosphate-activated protein kinase (AMPK) and protein kinase B (Akt). Here, we test the hypothesis that an analogous mechanism exists in vivo when the challenge is chronic exposure to hypoxia. METHODS: Five week-old mice were exposed to an atmosphere containing 10% O2 for 10 days. Mice were gavaged daily with vehicle, creatine, D-ribose or creatine + D-ribose. After sacrifice, myocardial and pulmonary tissue were harvested for structural and biochemical analyses. RESULTS: Hypoxia induced right ventricle hypertrophy and left ventricle apoptosis. Both phenotypes were slightly reduced by either creatine or D-ribose, whereas the simultaneous administration of creatine + D-ribose almost completely reversed the effects of hypoxia. Furthermore, creatine + D-ribose diminished the hypoxia-induced increases in the activity of AMPK, Akt and JNK, but not of ERK. Finally, the hypoxia-induced pulmonary overexpression of endothelin-1 mRNA was markedly reduced by creatine + D-ribose. CONCLUSION: The simultaneous administration of creatine + D-ribose confers additional cardiovascular protection with respect to that observed with either creatine or D-ribose. The mechanism stems from the AMPK and Akt signaling pathways. These findings may form the basis of a paradigm to re-energize non-irreversibly damaged cardiomyocytes, counteracting injury by triggering specific signaling pathways.
Asunto(s)
Apoptosis/efectos de los fármacos , Hipoxia de la Célula , Creatina/administración & dosificación , Hipertrofia Ventricular Derecha/prevención & control , Ribosa/administración & dosificación , Animales , Secuencia de Bases , Western Blotting , Creatina/farmacología , Cartilla de ADN , Masculino , Ratones , Ratones Endogámicos ICR , Reacción en Cadena en Tiempo Real de la Polimerasa , Ribosa/farmacología , Transducción de SeñalRESUMEN
BACKGROUND/AIMS: To alleviate ischemia-induced injury in the myocardium, a tissue that depends critically on energy-yielding processes, creatine may be used to enhance energy metabolism, whereas D-ribose may provide building blocks for ATP synthesis. We test the hypothesis that simultaneous supplementation of creatine+D-ribose protects non-irreversibly injured ischemic cardiomyocytes by reducing apoptosis. RESULTS: When H9c2 cardiomyocytes were exposed to 24-h ischemia (1% O(2) with glucose deprivation), viability was severely compromised, but administration of 2.5 mM creatine + 5 mM D-ribose alleviated the fall in viability, whereas 2.5 mM creatine or 5 mM D-ribose did not. These findings correlated with up-regulation of protein kinase B (Akt) phosphorylation. Creatine+D-ribose also blunted adenosine monophosphate-activated protein kinase (AMPK) and down-regulated apoptosis by reducing caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage. CONCLUSIONS: Simultaneous administration of creatine+D-ribose confers anti-ischemic protection that was absent when treating cardiomyocytes with either creatine or D-ribose. The involved mechanisms stem from the Akt and AMPK signaling pathways. These findings may form the basis of a paradigm whereby re-energization of non-irreversibly damaged cardiomyocytes is a critical step to counteract apoptosis.