Fluorescence Activated Cell Sorting (FACS) MSC were detached using 0.25% trypsin-EDTA (Sigma, Buchs, Switzerland) for about 30 s and washed useful site twice. Cells were stained with antibodies (Ab) against CD11b, CD31, CD34, CD36, CD44, CD45, CD54, CD90, CD105, CD106, HLA ABC, and mouse isotype control, at saturating concentrations. Cells were washed with phosphate buffered saline (PBS) containing 0.1% bovine serum albumin (BSA) and 0.1% azide (all from Sigma, Buchs, Switzerland) and those labeled with unconjugated Ab were secondary labeled with FITC or PE secondary rat anti-mouse Ab, washed and analyzed using a FACScan flow cytometry system (Becton Dickinson Immunocytometry Systems, Basel, Switzerland). Mouse isotype standard immunoglobulin and secondary Ab alone were used as negative controls.

Data were analyzed using Win MDI program (Scripps, La Jolla, Ca, USA). Mesodermal differentiation Adipogenic differentiation: Adult MSC and pMSC were trypsinized and seeded at high density (20��000�C25��000 cells/cm2). MSC were cultured at 37��C in presence of 5% CO2 for 3 weeks on adherent Petri dishes (Falcon, Becton Dickinson, Basel, Switzerland) in adipogenic differentiation media composed of IMDM, 10% rabbit serum (Sigma, Buchs, Switzerland), 0.5 mM 3-Isobutyl-1-methylxanthin (IBMX), 1 ��M hydrocortisone, 0.1 mM indomethacin (all from Sigma, Buchs, Switzerland) and P�CS. Media were changed every 3 d. Cells were fixed with cold 10% formalin for 1 h, then washed twice with water and stained with Oil-red-O solution (Sigma, Buchs, Switzerland) for 2 h at room temperature (RT), to reveal triglyceride droplets in the cytoplasm.

Cells were washed twice, coverslipped and observed under an optical microscope (Zeiss Axiophot1, Carl Zeiss AG, Feldbach, Switzerland). Osteogenic differentiation: Adult MSC and pMSC were trypsinized and seeded at high density (20��000�C25��000 cells/cm2). Then, cells were cultured at 37��C with 5% CO2 up to 3 weeks on adherent Petri dishes in osteogenic differentiation media based on IMDM, dexamethasone 0.1 ��M, ��-glycerolphosphate 10 mM, ascorbic acid 200 ��M (all from Sigma, Buchs, Switzerland), and P�CS. Media was changed every 3 d. Cells were fixed in 10% formalin for 1 h and were either stained with von Kossa staining to detect calcium deposition or stained using alkaline phosphatase activity test. Briefly, for von Kossa staining, after fixation cells were rinsed with distilled water and incubated with a 5% Silver Nitrate Brefeldin_A solution under strong light for 5 min at RT. After washing with distilled water, coloration was fixed with a 1% sodium thiosulfate solution for 5 min, washed again and nuclei were stained with Nuclear Red for 15 min at RT. Cells were washed twice and observed under an optical microscope (Zeiss Axiophot1).