REGULAR ARTICLE Multi-potent progenitors in freshly isolated and cultured human mesenchymal stem cells: a comparison between adipose and dermal tissue Ivana Manini & Letizia Gulino & Barbara Gava & Enrico Pierantozzi & Carlo Curina & Daniela Rossi & Anna Brafa & Carlo D’Aniello & Vincenzo Sorrentino Received: 22 August 2010 / Accepted: 26 January 2011 # Springer-Verlag 2011 Abstract Mesenchymal stem cells (MSCs) from human adult adipose tissue (A-MSCs) have a better differentiative ability than MSCs derived from the derma (D-MSCs). To test whether this difference is associated with differences in the content of multi-potent progenitors in A-MSCs, the number and the differentiative properties of multi-potent progenitors have been analyzed in various preparations of A-MSCs and D-MSCs. Adipogenic and osteogenic differ- entiation performed on colony-forming units have revealed that adipogenic and osteogenic progenitors are similar in the two populations, with only a slighty better performance of A-MSCs over D-MSCs from passages p0 to p15. An analysis of the presence of tri-, bi-, uni- and nulli-potent progenitors isolated immediately after isolation from tissues (p0) has shown comparable numbers of tri-potent and bi- potent progenitors in MSCs from the two tissues, whereas a higher content in uni-potent cells committed to adipocytes and a lower content in nulli-potent cells has been observed in A-MSCs. Furthermore, we have characterized the progenitors present in A-MSCs after six passages in vitro to verify the way in which in vitro culture can affect content in progenitor cells. We have observed that the percentage of tri-potent cells in A-MSCs at p6 remains similar to that observed at p0, although bi-potent and uni-potent progenitors committed to osteogenic differentiation increase at p6, whereas nulli-potent cells decrease at p6. These data indicate that the greater differentiative ability of A-MSC populations does not correlate directly with the number of multi-potent progenitors, suggesting that other factors influence the differentiation of bulk populations of A-MSCs. Keywords Mesenchymal stem cells . Adipose tissue . Differentiation . Progenitor cells . Human Introduction Mesenchymal stem cells (MSCs) represent a population of adult mesenchymal progenitor cells with the potential to differentiate not only into a variety of mesodermal cell types, such as pre-adipocytes, osteocytes and chondrocytes but also, with minor efficiency, into skeletal, cardiac and smooth muscle cells (Castro-Malaspina et al. 1980; Caplan 1991; Galmiche et al. 1993; Prockop 1997; Pittenger et al. 1999; Reyes et al. 2001; LaBarge and Blau 2002). Furthermore, MSCs can acquire morphologic and phenotypic character- istics of cells of non-mesodermal origin, such as neuronal cells, insulin-secreting cells and hepatic cells (Petersen et al. 1999; Theise et al. 2000; Deng et al. 2001; Sanchez-Ramos 2002; Woodbury et al. 2000; Jiang et al. 2002; D'Ippolito et al. 2004; Gallo et al. 2007). Originally, MSCs were Ivana Manini and Letizia Gulino contributed equally to this work. This work was supported by grants from the Regione Toscana and from the Fondazione Monte dei Paschi di Siena. Electronic supplementary material The online version of this article (doi:10.1007/s00441-011-1139-0) contains supplementary material, which is available to authorized users. I. Manini : L. Gulino : B. Gava : E. Pierantozzi : C. Curina : D. Rossi : V. Sorrentino (*) Molecular Medicine Section, Department of Neuroscience, and Center for Stem Cell Research, University of Siena, Via Aldo Moro, 53100 Siena, Italy e-mail: v.sorrentino@unisi.it A. Brafa : C. D’Aniello Plastic and Reconstructive Surgery Unit, University of Siena, Siena, Italy Cell Tissue Res DOI 10.1007/s00441-011-1139-0