The Response of Bone Marrow-Derived Mesenchymal Stem Cells to Dynamic Compression Following TGF-β3 Induced Chondrogenic Differentiation

Abstract

The objective of this study was to investigate the hypothesis that the application of dynamic compression following transforming growth factor-beta3 (TGF-beta3) induced differentiation will further enhance chondrogenesis of mesenchymal stem cells (MSCs). Porcine MSCs were encapsulated in agarose hydrogels and cultured in a chemically defined medium with TGF-beta3 (10 ng/mL). Dynamic compression (1 Hz, 10% strain, 1 h/day) was initiated at either day 0 or day 21 and continued until day 42 of culture; with TGF-beta3 withdrawn from some groups at day 21. Biochemical and mechanical properties of the MSC-seeded constructs were evaluated up to day 42. The application of dynamic compression from day 0 inhibited chondrogenesis of MSCs. This inhibition of chondrogenesis in response to dynamic compression was not observed if MSC-seeded constructs first underwent 21 days of chondrogenic differentiation in the presence of TGF-beta3. Spatial differences in sGAG accumulation in response to both TGF-beta3 stimulation and dynamic compression were observed within the constructs. sGAG release from the engineered construct into the surrounding culture media was also dependent on TGF-beta3 stimulation, but was not effected by dynamic compression. Continued supplementation with TGF-beta3 appeared to be a more potent chondrogenic stimulus than the application of 1 h of daily dynamic compression following cytokine initiated differentiation. In the context of cartilage tissue engineering, the results of this study suggest that MSC seeded constructs should be first allowed to undergo chondrogenesis in vitro prior to implantation in a load bearing environment.

Expansion in the presence of FGF-2 enhances the functional development of cartilaginous tissues engineered using infrapatellar fat pad derived MSCs

“…The observed beneficial effects of expanding in the presence of FGF-2 is consistent with previous findings for other sources of stem cells in terms of more rapid proliferation and improved chondrogenic potential evident by increased levels of matrix synthesis (Solchaga et al 2005;Khan et al 2008;Solchaga et al 2010). After 3 weeks of in vitro culture, IFP derived MSCs expanded in the presence of FGF-2 generated cartilaginous grafts whose mechanical functionality was at least comparable to that which we have previously reported using other cell types from the same species at the same time point (Thorpe et al 2008;Buckley et al 2010a;Meyer et al 2010;Thorpe et al 2010;Vinardell et al 2010). The ability to achieve high cell yields with substantial chondrogenic potency within a short time frame has significant implications for the development of more rapid cell based therapies.…”

“…Therefore identifying expansion and differentiation conditions that promote a more chondrogenic phenotype is critical to enhancing their utility for cartilage tissue engineering applications. Differentiation conditions that have been shown to promote the chondrogenic potential of MSCs include a low oxygen (5%) microenvironment (Khan et al 2007;Buckley et al 2010a;Meyer et al 2010), various combinations of growth factors (Mastrogiacomo et al 2001;Sakimura et al 2006;Hennig et al 2007;Diekman et al 2010;Buxton et al 2011) and mechanical signals (Huang et al 2005;Mauck et al 2007;Huang et al 2010a;Huang et al 2010b;Kelly and Jacobs 2010;Li et al 2010; Thorpe et al 2010;Haugh et al 2011). …”

Osteogenic Differentiation of Mesenchymal Stem Cells by Mimicking the Cellular Niche of the Endochondral Template

“…Another limitation of this study is the use of ascorbic acid and dexamethasone in the chondrogenic medium, which might be expected to cause MSCs to differentiate toward the osteogenic lineage. However, the use of dexamethasone and ascorbic acid in the chondrogenic medium is well documented 53,60,66,78,[91][92][93][94][95][96][97][98][99][100][101][102] and has not been shown to cause mineralization. Moreover, alizarin red staining of the aggregates before the coculture showed no positive staining and the control groups were all exposed to the same chondrogenic medium, so any differences seen between the groups were not because of exposure to these growth factors.…”

Engineering osteochondral constructs through spatial regulation of endochondral ossification

“…Well documented limitations associated with chondrocytes [28][29] have led to increased interest in the use of mesenchymal stem cells (MSCs) for functional cartilage tissue engineering strategies [30][31][32][33][34][35][36][37]. A major challenge in MSC based cartilage repair therapies is the prevention of terminal differentiation as maintenance of the chondrogenic phenotype is critical in order to ensure the long-term in vivo stability of a cartilaginous graft [38].…”