"In vitro" and multicolor phenotypic characterization of cell subpopulations identified in fresh human adipose tissue stromal vascular fraction and in the derived mesenchymal stem cells

Giuseppe Astori¹ , Francesca Vignati¹ , Silvana Bardelli¹ , Monica Tubio¹ , Mauro Gola¹ , Veronica Albertini¹ , Franco Bambi² , Giancarlo Scali³ , Damiano Castelli³ , Valeria Rasini⁴ , Gianni Soldati¹ and Tiziano Moccetti¹

¹Cell Therapy Unit, Cardiocentro Ticino, Via Tesserete 48, CH-6900 Lugano, Switzerland

²Blood Bank and Cell Therapy Unit, Department of Hematology-Oncology, Children's Hospital A. Meyer, Via L. Giordano 13, 50132-Florence, Italy

³Swiss Red Cross Blood Transfusion Service, Via Tesserete 50, CH-6900 Lugano, Switzerland

⁴Laboratory of Cell Biology and Advanced Cancer Therapies, University of Modena and Reggio Emilia, Via del Pozzo, 71, 41100-Modena, Italy

author email corresponding author email

Journal of Translational Medicine 2007, 5:55doi:10.1186/1479-5876-5-55


Published:	31 October 2007

Abstract

Background

The stromal vascular fraction (SVF) is a heterogeneous cell population derived from the adipose tissue. There is still a lack of information concerning the characterization of the cell subpopulations constituting the SVF as well as its mesenchymal and haematopoietic potential. Furthermore there are great variations in its phenotypical characterization.

Methods

Composition of SVF was investigated by FACS analysis, cytological and "in vitro" assays. We studied CD34+ population by combining FACS with human CFC (colony-forming-cell haematopoietic assay). The endothelial fraction was investigated by quantifying the co-expression of specific markers (CD146, CD105, CD31 and UEA-1). Mesenchymal potential was assessed by CFU-F assay and cultured AT-MSC were characterized by a 5-color FACS analysis. The multipotent differentiation potential (osteogenic, adipogenic and chondrogenic) was investigated both at cellular and molecular level.

Results

We identified in the SVF two CD34+ populations with a marked difference in the intensity of antigen expression, the majority of the cells expressing CD34 at low intensity. Moreover, two CD146+ cell populations were clearly distinguishable in the SVF:a CD146 dim accounting for 9.9% of the total SVF cells and a CD146+ bright cell population accounting for about 39.3%. The frequency of CFC clones was comparable with the one reported for peripheral blood. Endothelial cells account for about 7.7% of the SVF cells. AT-MSC differenced in the osteogenic adipogenic and chondrogenic lineage.

Conclusion

The SVF is not a homogeneous cell population, and its final composition could be influenced both by the flow cytometric technique analysis and the SVF extraction steps. The CFU-F frequency in the SVF was 1/4880, a value about seven times greater than the data reported for bone marrow. The antigenic profile of AT-MSC was comparable with bone-marrow derived MSC. AT-MSC were able to differentiate along the osteogenic adipogenic and chondrogenic lineages. The data here reported, further contribute to the characterization of SVF, a tissue providing an alternative as a source of MSC for clinical applications.