Intramembranous bone matrix is osteoinductive

Abstract

All known bone-derived osteoinductive factors have been isolated from endochondral (EC) bones and all initiate bone induction via EC ossification. However, to date no attempt has been made to isolate comparable factors from bones which form initially and completely via intramembranous (IM) ossification. The purpose of this work was to isolate osteoinductive proteins from IM bones. To accomplish this, we extracted proteins from bovine frontal bone matrix (intramembranous origin) using methods previously described for endochondral (EC) bone matrix (i.e., femur). Bone powder (< 1 mm) was decalcified and proteins extracted with 4 M guanidine hydrochloride. Ultrafiltration was used to isolate and concentrate a 10-100 kilodalton (kDa) fraction, upon which heparin-Sepharose (HS) affinity chromatography was performed. HS-binding (HS-B) and non-binding proteins (HS-NB) were lyophilized with bovine type I collagen (Vitrogen) to form pellets which were implanted subcutaneously in rats. Radiology as well as brightfield, fluorescent, and polarizing microscopy were used to assess the formation of ectopic bone at the site of pellet implantation. In this report we demonstrate that a heparin-Sepharose binding, osteoinductive factor can be extracted and partially purified from bovine intramembranous bone matrix. This factor has a different sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) banding pattern than a comparable osteoinductive/chondroinductive factor isolated from EC bone.

BMPs induce endochondral ossification in rats when implanted ectopically within a carrier made of fibrous glass membrane

“…Scott and her colleagues suggested that osteoinductive proteins from intramembranous bones could induce direct bone formation without catilage, whereas ones from endochondral bones could cause endochondral ossification (Scott and Hightower, 1991;Scott et al, 1994). In contrast, we suggest that BMPs from endochondral bone can induce either direct or endochondral bone formation, depending on the physicochemical property of the carrier.…”

A quantitative assessment of the healing of intramembranous and endochondral autogenous bone grafts

“…Similar results were reported by Moskalewski and co-workers (1988), who also suggested that osteoblasts from EC scapular bone have different HEALING OF AUTOGENOUS BONE GRAFTS properties from those of IM calvarial bone. Furthermore, an osteo-inductive factor has been extracted from IM bone which is different from that of EC bone (Scott et al, 1994). A heparin sepharose-binding, osteo-inductive factor, extracted from bovine IM bone matrix and partially purified, exhibited a different molecular mass than that of a comparable osteo-inductive factor isolated from EC bone.…”

Subperiosteal lmplantation of octacalcium phosphate (OCP) stimulates both chondrogenesis and osteogenesis in the tibia, but only osteogenesis in the parietal bone of a rat

“…Previous studies suggested that matrix of long bone contains osteoinductive factors to induce endochondral ossification in contrast to those of calvarial bone matrix, which induce only intramembranous ossification without chondrogenesis (Scott and Hightower, 1991;Scott et al, 1994). Osteogenic cells from endochondral bone such as scapulas and femurs have been suggested to have different properties than those from intramembranous bones such as calvaria (Moskalewski et al, 1988;Denkovski et al, 1994).…”

“…A previous study reported that injection of exogenous TGF-beta into the subperiosteal region of murine long bones caused both intramembranous and endochondral bone formation (Joyce et al, 1990), whereas others showed that TGFbeta induced intramembranous bone formation without prior formation of cartilage in murine calvaria (Noda and Camilliere, 1989;Tanaka et al, 1993). The cellular response to TGF-beta of stimulating bone formation with or without chondrogenesis appears related to the committed phenotype a t the site of TGF-beta administration (Scott et al, 1994). However, no direct 0 1995 WILEY-LISS, INC comparison of the biological response to TGF-beta between the long bone and the calvarium has been made in any experiment of those studies.…”