Recombinant human bone morphogenetic protein‐2 promotes osteogenesis within atelopeptide type I collagen solution by combination with rat cultured marrow cells

Abstract

We evaluated the combination effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) and cultured rat bone marrow mesenchymal stem cells (MSCs) in atelopeptide type I collagen (AC) solution on osteogenesis in a diffusion chamber (DC) to develop a bone substitute having consistent osteogenic capability for clinical applications. The cultured MSCs were obtained by 10-day primary culture of fresh bone marrow cells of Fischer rats. We prepared three groups of DCs: AC solution with rhBMP-2, AC solution with cultured MSCs, and AC solution with rhBMP-2 and cultured MSCs. The prepared combined solutions were injected into DCs, which were subcutaneously implanted into the backs of syngeneic rats. DCs were harvested after 2, 4, or 8 weeks and analyzed for bone-forming capability by determining histological and osteoblastic biochemical markers. De novo bone formation was observed both inside and outside of the membrane filter of DCs in the group of AC solution with rhBMP-2 and cultured MSCs. The alkaline phosphatase activity and osteocalcin content in the group of AC solution with rhBMP-2 and cultured MSCs were significantly higher than those in the group of AC solution with cultured MSCs at any time. These findings indicate that AC aqueous solution is a useful material not only as a carrier of rhBMP-2 but also as a cell-anchorage for differentiation and proliferation of MSCs. Therefore, this study suggests that clinical repairs of bone defects are feasible using injectable AC solution with rhBMP-2 and cultured MSCs as a bone substitute.

Recombinant growth/differentiation factor‐5 (GDF‐5) stimulates osteogenic differentiation of marrow mesenchymal stem cells in porous hydroxyapatite ceramic

“…We also reported that BMP-2/collagen/MSCs in the diffusion chambers (DC) showed bone formation on the surface areas of the membrane filter and cartilage formation in the central areas of the DC. 17 Furthermore, it should be noted that the current HA ceramics we used were derived from coral, and the complete interpore connection resulted in an open-pore structure. The three-dimensional structure easily intro- duces neovascular invasion into the pore areas, and bone formation always accompanies the vasculature.…”

“…In addition, collagen gel combined with BMP-2 and MSCs could be used as injectable and resorbable osteogenic materials. 17 Other resorbable materials available for this purpose include polyglycolic acid polymer and hydroxyapatite/collagen-poly-l-lactic acid composite. 32,33 In conclusion, when GDF-5 was used for making composite grafts in combination with porous materials and marrow MSCs, it was able to induce new bone formation without the appearance of cartilage.…”

“…17 Briefly, each HA disk was crushed, homogenized in 0.2% Nonidet P-40/50 mM Tris-HCl buffer containing 1 mM MgCl 2 , and centrifuged at 13,000 g for 15 min at 4°C. An aliquot of supernatant was assayed for ALP activity using p-nitrophenyl phosphate as a substrate.…”

Growth factor delivery-based tissue engineering: general approaches and a review of recent developments

“…Biopolymeric gels for immobilization of growth factors. Biopolymeric gels containing fibronectin, laminin, collagen, elastin or the glycosaminoglycans heparin sulphate, chondroitin sulphate, hyaluronic acid or a variety of synthetic hydrogels have been used as extracellular matrix-mimicking materials to immobilize growth factor-inducing moieties or growth factors directly [61,62]. For example, fibrin, which plays an important role in wound healing, has been used to link and deliver peptides or growth factors into the area of interest.…”

Osteogenic Potential of Human Adipose Tissue-Derived Stromal Cells as an Alternative Stem Cell Source

“…Current studies mainly rely on the use of fresh autograft bone and various bone graft substitutes [Saito et al, 2001;Boo et al, 2002;Ikeuchi et al, 2002]. We believe that future strategies for the repair of bone defects could include the use of tissue engineering techniques that incorporate appropriate implants seeded with cells having an osteogenic potential.…”