Will Mesenchymal Stem Cells Differentiate into Osteoblasts on Allograft?

Abstract

Tissue engineering approaches for bone blocks previously have used synthetic scaffolds. Bone graft (allograft) is used to fill bone defects, but standard processing can lessen this scaffold's osteoinductive potential. We wanted to test if allografts could be used to produce a viable bone block using mesenchymal stem cells. We hypothesized that mesenchymal stem cells differentiate into osteoblasts producing extracellular matrix when cultured on allografts. We also hypothesized that the addition of osteogenic supplements would increase the rate of differentiation. To test these hypotheses, mesenchymal stem cells were isolated from bone marrow aspirated from 10 patients and cultured on allografts from five donors (Group 2), producing 50 samples. This was repeated on allografts heat-treated to denature bioactive proteins (Group 1), and repeated again on allografts to which osteogenic supplements (Group 3) were added. Group 2 mesenchymal stem cells differentiated into osteoblasts producing higher levels of alkaline phosphatase, osteopontin, and Type I collagen matrix protein than Group 1. The rate of differentiation of Group 3 mesenchymal stem cells increased with the supplements. Overall, it was established that the bioactive proteins in the allograft stimulated mesenchymal stem cell differentiation into osteoblasts, with production of extracellular matrix, and that this differentiation increased with the addition of osteogenic supplements.

Effect of bone graft substitute on marrow stromal cell proliferation and differentiation

“…The substrates evaluated in this study are bone, calcium polyphosphate (CPP), biphasic hydroxyapatite/tricalcium phosphate (HA/TCP), and their effect on MSCs was compared with that of tissue culture plastic (TC). Autogenic and allogenic bone is currently the most commonly used bone graft material 20,21 with a natural composition and structure that makes it an ideal scaffold for bone healing and remodeling. CPP is a novel ceramic currently being investigated for its use in cartilage repair due to its good biocompatibility and mechanical properties.…”

Freeze‐dried human serum albumin improves the adherence and proliferation of mesenchymal stem cells on mineralized human bone allografts

“…2,3 One explanation can be that colonization of the graft by stem cells is too slow and falls below the threshold for bone remodeling. [4][5][6] The ideal bone graft can be characterized by good mechanical strength, osteoinductive, osteoconductive, and osteogenic capabilities and only the autologous human bone graft possesses all of the mentioned properties. 7 The unique bone healing potential of autologous bone graft stems from its three well-defined features: (a) osteoconductivity is provided by the structure of native bone, (b) osteoinductivity is given by morphogenetic proteins and other growth factors, and (c) osteogenicity is provided by cells, like osteoblasts, osteoclasts, and mesenchymal stem cells (MSCs) which are on the surface of a freshly harvested autologous bone graft.…”

The use of structural proximal tibial allografts coated with human albumin in treating extensive periprosthetic knee-joint bone deficiency and averting late complications. Case report

“…Ezen a hiányosságon kívántunk javítani az albuminbevonattal. Esetünk példa arra, hogy az allograft felszíni kezelése javítja az átépü lési készséget [13,14,15,19]. Szintén a korábbi adatokat alátámasztó tény -mármint hogy az osteoporosis, illetve az osteolysis okozza az aszeptikus lazulással járó szövőd-ményeket -, hogy esetünkben is a graft-csont találkozás alatt történt a tibia törése, aminek oka természetesen a trauma volt, de a lokalizáció az osteoporosis követ-kezménye.…”