Methods and compositions are described enhancing bone density or formation, including for stabilizing bone grafts, bone repair, joint replacement, and cartilage repair that includes providing a composition including Del-1 locally to a site for enhancing bone density or formation, or to a culture or chondrocytes or multipotent chondrocyte precursor cells, whereby survival or differentiation of chondrocytes at the site is enhanced, thereby ultimately enhancing bone density or formation. Methods and compositions for stimulating hair regrowth are also provided.