$MYOS Myos is evaluating the genotypic characteristics and molecular pathways that contribute to the changes seen in muscle and inflammatory disease states associated with sarcopenia and related disorders. We are investigating the role of many signaling pathways including activin A, myostatin and follistatin on fundamental biologic processes important in the repair and regeneration of muscle tissue, including those regulating proliferation and differentiation of primary myoblasts. Our research also examines the role of natural and synthetic molecules, including follistatin in regulating myostatin activity, as well as how myostatin modulation effects the growth, retention and repair of lean muscle.