csa (cyclosporin a) has been shown to decrease cardiac hypertrophy by affecting cardiac myocytes in many ways. csa binds to cyclophilin d to block the opening of mptp, and thus decreases the release of protein cytochrome c, which can cause programmed cell death. cypd is a protein within the mptp that acts as a gate; binding by csa decreases the amount of inappropriate opening of mptp, which decreases the intramitochondrial . decreasing intramitochondrial allows for reversal of cardiac hypertrophy caused in the original cardiac response. decreasing the release of cytochrome c caused decreased cell death during injury and disease. csa also inhibits the phosphatase calcineurin pathway (14). inhibition of this pathway has been shown to decrease myocardial hypertrophy.