Disclosed herein are methods and compositions for the treatment and/or prevention of diseases or conditions comprising administration of an MPP, and/or naturally or artificially occurring variants or analogues of an MPP, or pharmaceutically acceptable salts thereof, alone or in combination with one or more active agents (e.g., an aromatic-cationic peptide such as D-Arg-2'6'-Dmt-Lys-Phe-NH2).
