A method of preventing or treating a condition associated with a defect in or damage to an organ or a tissue of such organ in a subject with, or at risk for, such defect or damage to such organ or tissue which comprises administering to the subject a prophylactically or therapeutically effective amount of a fully reduced (all thiol) form of HMGB1 or of a biologically active truncated form of HMGB1, so as to prevent or treat such condition, wherein the subject is, or is anticipated to be, in need of prevention or treatment of the condition in the future, and wherein the organ or tissue relies on repair by stem or parenchymal cells that express the cell surface receptor CXCR4.