The fate of bovine bone marrow stromal cells in hydrogels: a comparison to nucleus pulposus cells and articular chondrocytes

Bone marrow-derived stromal cells (BMSCs) are good candidates for cell-based tissue regeneration. For such purposes, cell survival within three-dimensional (3D) scaffolds is often desirable. We hypothesize that undifferentiated BMSCs will have difficulties thriving within these gels, in contrast to articular chondrocytes (ACs) and nucleus pulposus cells (NPCs), but that early chondrogenic differentiation of the former will increase their survival. BMSCs, ACs and NPCs cast in 1.2% alginate or 2% agarose were cultured for 21 days in serum-containing media. BMSCs were also cultured in medium with 10 ng/ml TGF-beta 1. By day 21, NPCs and ACs proliferated, maintained upregulation of aggrecan and collagen type II, produced glycosaminoglycans and stained positively for collagen type II in both scaffolds. In contrast, the number of living BMSCs and the DNA content of their constructs decreased in both scaffolds. Addition of TGF-beta(1), resulted in cell survival and behaviour more similar (gene expression, glycosaminoglycan production and collagen type II synthesis) to ACs and NPCs. This study demonstrated that, unlike ACs and NPCs, undifferentiated BMSCs have more difficulty thriving within hydrogels, but that this can be improved by chondrogenic induction. Hence, immediate conditioning of BMSCs could be a worthwhile strategy. Copyright (c) 2009 John Wiley & Sons, Ltd.