Gelatin-based resorbable sponge as a carrier matrix for human mesenchymal stem cells in cartilage regeneration therapy

Adult mesenchymal stem cells (MSCs), found in the bone marrow, have the pot ential to differentiate into multiple connective tissue types, including ca rtilage. In this study, we examined the potential of a porous gelatin spong e, Gelfoam, for use as a delivery vehicle for MSCs in cartilage regeneratio n therapy. Adult human MSCs (hMSCs) were seeded throughout the gelatin spon ge after a 2-h incubation period. When cultured for 21 days in vitro in a d efined medium supplemented with 10 ng/mL of TGF-beta 3, hMSC/Gelfoam constr ucts produced a cartilage-like extracellular matrix containing sulfated gly cosaminoglycans (sGAGs) and type-II collagen, as evident upon histologic ev aluation. Constructs loaded with a cell suspension of 12 x 10(6) cells/ms p roduced an extracellular matrix containing 21 mu g of s-GAG/mu g of DNA aft er 21 days of culture. This production was more efficient than constructs l oaded at higher or lower cell densities, indicating that the initial seedin g density influences the ability of cells to produce extracellular matrix. When implanted in an osteochondral defect in the rabbit femoral condyle, Ge lfoam cylinders were observed to be very biocompatible, with no evidence of immune response or lymphocytic infiltration at the site. Based on these ob servations we conclude that Gelfoam resorbable gelatin sponge is a promisin g candidate as a carrier matrix for MSC-based cartilage regeneration therap ies. (C) 2000 John Wiley & Sons, Inc.