Donor-matched functional and molecular characterization of canine mesenchymal stem cells derived from different origins.

Canine mesenchymal stem cells (cMSCs) have generated a great interest as a promising source for cell-based therapies. To understand the basic biological properties of cMSCs derived from bone marrow (cBM-MSCs), adipose tissue (cA-MSCs), and dermal skin (cDS-MSCs) from a single donor, the present study compared their alkaline phosphatase (AP) activity, expression of CD markers and stem cell transcription factors, differentiation ability into osteogenic, adipogenic, and chondrogenic lineages, in vivo ectopic bone formation, chromosomal stability, cell cycle status, telomere length, and telomerase activity. Expressions of AP activity and transcription factors (Oct3/4, Nanog, and Sox2) were either absent or extremely weak in all cMSCs. CD marker profile (CD45(-), CD90(+), and CD105(+)) and differentiation capacity were exhibited by all cMSCs, although cA-MSCs had enhanced cytochemical staining associated with expression of lineage-specific markers. In vivo bone formation of cMSCs was performed with demineralized bone matrix (DBM) by transplanting into the subcutaneous spaces of 9-week-old BALB/c-nu mice, followed by radiographic and histological analysis after 1 and 2 months. cA-MSCs and cDS-MSCs, in contrast to the in vitro observations, also displayed higher in vivo osteogenic abilities than cBM-MSCs. Ploidy analysis showed that cells were diploid and contained no noticeable chromosomal abnormalities. Furthermore, a relatively low percentage of cells was found at the G1 phase in all cMSCs, especially in DS-MSCs. Regardless of the different tissue sources, cMSCs from a single donor showed no differences in telomere lengths (∼18-19 kbp) but exhibited varied telomerase activity. The above results suggest that tissue-specific cMSCs derived from a single donor possess slight differences in stem cell properties.