Lack of activation of telomere maintenance mechanisms in human adipose stromal cells derived from fatty portion of lipoaspirates

Background: Significant improvement in the understanding of mesenchymal stem cell biology paved the way to their clinical use. Human lipoaspirates derived from mesenchymal stem cells (adipose-derived stem cells) continue to draw the attention of researchers in the field of basic and applied research due to their regenerative, reparative, angiogenic, antiapoptotic, and immunosuppressive properties, all of which collectively point out their therapeutic potential. There is still, however, a need for further investigation to improve the knowledge of stem cell biology, to broaden their field of use, and to enhance their therapeutic effectiveness. Methods: The authors characterized human adipose-derived stem cells at different in vitro culture time points in terms of immunophenotype, multilineage differentiation, long-term survival with self-renewal capacity, and presence of telomere maintenance mechanisms (telomerase activity and alternative lengthening of telomere) for excluding their eventual susceptibility to malignant transformation. Results: Adipose-derived stem cells were isolated from the abdomen and peritrochanteric region of 31 female donors, propagated, and monitored in vitro for several passages. The outgrown cells shared the biological properties of mesenchymal stem cells, with adherence to plastic, expression of the typical surface markers, and induction of adipogenic, osteogenic, and chondrogenic differentiation. Telomerase activity and alternative lengthening of telomere mechanisms at different passages of cultures were not evidenced. Conclusion: The results support the concept that in vitro expanded adiposederived stem cells obtained from fat tissue are not susceptible to developing one of the hallmarks of malignant transformation and can be considered amenable for cell therapy approaches.