Human ASCs undergo osteogenic differentiation in vivo.
Human ASCs transduced with a GFP encoding lentivirus were seeded in calvarial defects. (A) Histological analysis at 2 wks postoperative. The defect site (left) and contralateral aspect of the skull (right) from identical sections are imaged to show specificity of staining. (A, top) GFP immunohistochemistry, depicting evidence of human cells which appear brown. The contralateral side shows no GFP signal demonstrating the specificity of the stain. (A, middle) Type I Collagen (COL1A1) expression by in situ hybridization. (A, bottom) Runt related transcription factor 2 (RUNX2) expression by in situ hybridization. Staining can be seen in the uninjured contralateral periostium demonstrating specificity and can also be seen within the defect site. (B) Human osteogenic gene expression by qRT-PCR at 1 and 2 wks post-injury among hASC engrafted defects, including hALP, hRUNX2, *P<0.01.