16.0: Thursday, March 17, 2005

Bone Marrow Derived Mesenchymal Stem Cells Are A Source of Transforming Growth Factor Beta-3 in Unwounded Skin

Kimberly K. Lu, MD, Vincent Chan, MD, Lynne Wilson, Anne Hocking, PhD, and F. Frank Isik, MD.

Purpose: Recent studies have found that the progeny of bone marrow stem cell types can populate the skin and are involved in cutaneous wound repair. Our aim was to determine the function of the bone marrow-derived mesenchymal cells in normal skin. Materials and Methods: The skin from both mesenchymal cell (MC) enriched EGFP+ chimeric mice and hematopoietic cell (HC) enriched EGFP+ chimeric mice were enzymatically dispersed and sorted by flow cytometry into EGFP+ and EGFP- cell fractions. RNA was extracted and relative quantification examined by real time PCR. Results: EGFP+ cells isolated from the skin of MC chimeric mice expressed the majority of TGF3 mRNA in the skin and twice as much cyclin D1, but no increase in collagen III mRNA was seen. EGFP- cells from the MC EGFP+ chimeric mouse skin did not express significant levels of either collagen type III or TGF-3 mRNA, but did express the inflammatory mediator IL-6. EGFP+ cells from the HC chimeric mouse skin did not express significantly elevated levels of collagen, TGF1, TGF3, IL-1 or IL-6. Conclusion: We present further evidence that mesenchymal cells from the bone marrow home to normal uninjured skin and change the growth factor milieu in vivo.