Abstract
While carnitine overload appears to have therapeutic effects in pathological situations such as heart recovery after ischemia, its benefits as dietary supplementation for aerobic exercise have been questioned. We studied the effect of carnitine supplementation on the response of perfused rat heart to ischemia and reperfusion. Supplementation of the perfusion medium with 1mM carnitine had no effect on cardiac performance in normoxic hearts, although it lowered lactate production by nearly 80%. Carnitine did not affect the amount of lactate accumulated during 30 min of ischemia, which was recovered in the perfusate immediately after reperfusion. However, carnitine worsened tissue injury, as shown by the 70% increase in creatine kinase release. Carnitine also worsened the recovery of contractile function, as revealed by the slower increase in heart rate and contractile force. In addition, carnitine supplementation increased contracture of the heart shortly after reperfusion. Therefore, in conditions where it does not increase glucose oxidation, carnitine supplementation worsens both injury and recovery of contractile function after transient ischemia in perfused rat heart.
Resumen
Mientras que una sobrecarga de carnitina parece tener efectos terapéuticos en situaciones patológicas como la recuperación del corazón tras una isquemia, los beneficios como suplemento dietético en el ejercicio aeróbico se han cuestionado. Se estudia en el presente trabajo el efecto de un suplemento de carnitina sobre la respuesta del corazón perfundido de rata a la isquemia y reperfusión. El suplemento del medio de perfusión con carnitina 1 mM no produjo ningún efecto en los parámetros funcionales del corazón normóxico, a pesar de que redujo la producción de lactato en un 80%. La carnitina no alteró la cantidad de lactato acumulado durante los 30 min de isquemia, lactato que fue recuperado en el perfundido immediatamente después de la reperfusión. Sin embargo, la carnitina empeoró las lesiones tisulares como indicó el incremento en un 70% de la creatina quinasa liberada. La carnitina también empeoró la recuperación de la función contráctil. Así lo indicó la recuperación más lenta de la frecuencia cardíaca y de la fuerza de contracción. Además, la carnitina aumentó la contractura que aparecía en el corazón inmediatamente después de la reperfusión. Por lo tanto, en condiciones en la que no se produce un incremento de la oxidación de glucosa, el suplemento de carnitina empeora las lesiones y la recuperación de la función contráctil después de una isquemia transitoria en el corazón perfundido de rata.
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Díaz, R., Lorita, J., Soley, M. et al. Carnitine worsens both injury and recovery of contractile function after transient ischemia in perfused rat heart. J Physiol Biochem 64, 1–8 (2008). https://doi.org/10.1007/BF03168229
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DOI: https://doi.org/10.1007/BF03168229