Low-dose taurine upregulates taurine transporter expression in acute myocardial ischemia.

Taurine exerts a protective effect on cardiomyocytes. The aim of this study was to determine whether the protective effect of taurine is associated with the upregulation of taurine transporter (TAUT) expression in acute myocardial ischemia (AMI). To this end, we investigated TAUT expression in cultured cardiomyocytes exposed to hypoxia as well as in rats with AMI treated with or not with taurine. The morphology of cardiac tissues, the apoptosis of cardiomyocytes and cardiac function were examined. In addition, the taurine content and the expression of TAUT were measured. Our data demonstrated that taurine reversed the apoptosis induced by hypoxia and AMI, thereby, effectively protecting the myocardium. Taurine content and TAUT expression levels were significantly decreased when cardiomyocytes and cardiac tissues were subjected to hypoxic or ischemic stress, while the expression of cysteine sulfinate decarboxylase was unchanged. Moreover, treatment with taurine (100 mg/kg/day) significantly upregulated TAUT expression and elevated the taurine content in ischemic myocardial tissues. In vitro, the low-dose (40 mM) but not the high-dose (120 mM) administration of taurine significantly induced TAUT expression and elevated the intracellular taurine content in hypoxic cardiomyocytes. In conclusion, our data demonstrate that taurine exerts a protective effect on the ischemic myocardium. Low-dose but not high-dose taurine treatment upregulated TAUT expression and increased the intracellular taurine content in cardiomyocytes subjected to hypoxia as well as in AMI tissues.