Abstract: Thrombomodulin functional domains for use in promoting osteoblast functions and bone healing. Methods for stimulating bone regeneration, bone augmentation, treating a bone loss, a bone disorder and/or treating a bone-related disorder are disclosed. The method comprises administering, to a subject in need thereof a therapeutically effective amount of (I); a biologically, active recombinant polypeptide comprising, an amino acid sequence that is at least 80% identical to domains 2 and 3 of human thrombomodulin (TMD23); (II): an isolated polypeptide comprising recombinant TMD23 (rTMD23) or a biologically active recombinant variant thereof; or recombinant TMD23 (rTMD23) or a biologically active recombinant variant thereof, wherein the polypeptide is free of or lacking amino acid residues from domains 4 and 5 of the human thrombomodulin, and further wherein the biologically active variant thereof comprises an amino acid sequence that is at least 80% identical to the TMD23.