LOSS OF CARDIAC MYOFIBRILS - MECHANISM OF CONTRACTILE DEFICITS INDUCED BY TAURINE DEFICIENCY

It is well established that taurine deficiency is associated with myoc ardial contractile dysfunction; however, the mechanism is unknown. As a follow-up to finding reduced force generation in taurine-depleted ra t cardiac trabeculae, using either calcium or strontium activation, th is study examined alterations in ventricular fine structure and contra ctile proteins in animals made taurine deficient by in vivo treatment with a taurine transport antagonist, guanidinoethane sulfonate. Observ ations of ventricular ultrastructure showed disordered contractile fil aments and clear losses of myofibrillar bundles in association with ta urine deficiency. Biochemical analyses of ventricular contractile prot eins using polyacrylamide gel electrophoresis confirmed losses of the major sarcomeric proteins, myosin and actin. These findings provide a possible mechanism for the contractile deficits and cardiomyopathy des cribed in taurine-deficient animals.