Search

Background: Autologous fat grafting is a widely adopted surgical technique in both the reconstructive and aesthetic fields. This study aimed to compare centrifuged lipoaspirates harvested and refined by the Coleman technique with noncentrifuged lipoaspirates in terms of cell number and viability, phenotypic profile, and clonogenic and proliferative potential of adipose-derived stem cell (ADSC) populations., Methods: For each patient, both a centrifuged sample using the Coleman's technique and a noncentrifuged sample of adipose tissue were collected. Adipose-derived stem cells from both the centrifuged fraction (CF) and the noncentrifuged fraction (NCF) were isolated. The recovered ADSCs were used to set up flow cytometry analysis, colony-forming units-fibroblast (CFU-F) assays, and ADSC cultures., Results: The number of recovered cells was variable among the different donors but significantly higher in the CF donors. Cell viability, determined by the Trypan Blue dye assay, always exceeded 95 %, in both the CF and NCF fractions. Analysis of the putative ADSC subpopulations showed a significant enrichment of the mesenchymal and endothelial progenitors in CF compared with NCF. No differences in the clonogenic efficiency of the ADSC samples were observed when the same number of cells were plated from each fraction. On the contrary, when equal fat volumes were compared, the colony-forming ability of CF was always significantly higher than that of its NCF counterparts., Conclusions: This is the first study to comprehensively characterize the impact of Coleman's technique on the quality of lipoaspirates, showing that centrifugation is safe and feasible and does not impair cell viability, can augment the content in ADSC and the frequency of CFU-F, and reduces the number of proinflammatory blood cells.

Owing to their exposure on the cell surface and the possibility of being directly recognized with specific antibodies, glycosphingolipids have aroused great interest in the field of stem cell biology. In the search for specific markers of the differentiation of human bone marrow mesenchymal stem cells (hBMSCs) toward osteoblasts, we studied their glycosphingolipid pattern, with particular attention to gangliosides. After lipid extraction and fractionation, gangliosides, metabolically (3)H-labeled in the sphingosine moiety, were separated by high-performance TLC and chemically characterized by MALDI MS. Upon induction of osteogenic differentiation, a 3-fold increase of ganglioside GD1a was observed. Therefore, the hypothesis of GD1a involvement in hBMSCs commitment toward the osteogenic phenotype was tested by comparison of the osteogenic propensity of GD1a-highly expressing versus GD1a-low expressing hBMSCs and direct addition of GD1a in the differentiation medium. It was found that either the high expression of GD1a in hBMSCs or the addition of GD1a in the differentiation medium favored osteogenesis, providing a remarkable increase of alkaline phosphatase. It was also observed that ganglioside GD2, although detectable in hBMSCs by immunohistochemistry with an anti-GD2 antibody, could not be recognized by chemical analysis, likely reflecting a case, not uncommon, of molecular mimicry.

Objective: Endothelial progenitor cells (EPCs) are involved in neovessel formation. So far, therapeutic angiogenesis is hampered by the low frequency and limited proliferative potential of these cells isolated from peripheral blood. Recently, it has been shown that cord blood-derived EPCs (CB EPCs) can be ex vivo expanded on a clinical scale. In this study, we evaluated the expansion potential of CB EPCs together with their phenotypic, functional, and chromosomal stability over time., Materials and Methods: Flow cytometry, in vitro tube formation, and proliferation assays were performed to characterize CB EPC-derived cells. Chromosomal stability was evaluated by karyotype analysis. In vitro and in vivo tumorigenicity was evaluated by soft agar assay and injection into nonobese diabetic/severe combined immunodeficient mice, respectively., Results: We showed that CB EPC-derived cells displayed phenotypic and functional features of EPCs, although a process of maturation was observed over time. Although we confirmed that CB EPCs have a greater expansion potential compared to peripheral blood EPCS, we observed a high incidence of cytogenetic alterations (71%) in the expanded endothelial cell population, even at early times of culture. In two cases, spontaneous transformation in vitro was documented, but none of the samples tested showed tumorigenic potential in vivo. Conversely, no karyotype alterations have been observed on peripheral blood EPCs-derived cells., Conclusions: We confirm that CB represents a good source for clinical ex vivo expansion of EPCs. However, because of high frequency of karyotype alterations, these cells cannot be considered free of risk in clinical application.