Thursday, December 3, 2009

Adipose Tissue Stem Cells to Chondrocytes

High plasticity of pediatric adipose tissue-derived stem cells: too much for selective skeletogenic differentiation?

"We have used different methods to establish stem cells from adipose tissue (adipose-derived stem cells [ADSCs], adipose explant dedifferentiated stem cells [AEDSCs]) from several pediatric patients and investigated their phenotype and differentiation potential using monolayer and micromass cultures. We have also addressed the overlooked issue of selective induction of cartilage differentiation. ADSCs/AEDSCs from different patients showed a remarkably similar behavior. Pluripotency markers were detected in these cells, consistent with ease of reprogramming to induced pluripotent stem cells. Significantly, most ADSCs expressed markers of tissue-specific commitment/differentiation, including skeletogenic and neural markers, while maintaining a proliferative, undifferentiated morphology. Exposure to chondrogenic, osteogenic, adipogenic, or neurogenic conditions resulted in morphological differentiation and tissue-specific marker upregulation. These findings suggest that the ADSC "lineage-mixed" phenotype underlies their significant plasticity, which is much higher than that of chondroblasts we studied in parallel. Finally, whereas selective ADSC osteogenic differentiation was observed, chondrogenic induction always resulted in both cartilage and bone formation when a commercial chondrogenic medium was used; however, chondrogenic induction with a transforming growth factor β1-containing medium selectively resulted in cartilage formation."

"ADSCs expressed the mesenchymal markers CD44 (hyaluronic acid receptor), CD90 (Thy-1), and CD105 (endoglin)"

" with the exception of SOX2, transcripts for the pluripotency markers c-MYC, OCT4, NANOG, KLF4, and DNMT3B were detected in ADSCs from all patients tested"  Surprisingly, ADSC's do not express type II collagen by default.  They do express Aggrecan.  Type II collagen was induced by TGF-Beta1.

Chondroblasts in contrast to ADSC's express ColII and ALP by default.

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