Células madre mesenquimales para la regeneración de tejidos: ¿Por qué siguen siendo una promesa sin cumplir? / Mesenchymal stem cells for tissue regeneration: ¿Why are they still an unfulfilled promise?

Desde su descripción inicial, hace ya más de 40 años, las células madre mesenquimales (MSC) fueron reconocidas como una importante alternativa para el manejo de enfermedades caracterizadas por la pérdida aguda o crónica de tejido, gracias a su capacidad de proliferación y diferenciación, lo cual les permitiría sustituir las células perdidas y de esta forma recuperar la estructura y función. Cada vez es más abundante la evidencia que sugiere el potencial de estas células para el manejo de un amplio grupo de enfermedades, al menos en modelos experimentales preclínicos. No obstante, esta capacidad no ha podido refrendarse contundente y consistentemente en ensayos clínicos. Con la presente revisión, se pretende presentar una visión del estado actual del desarrollo conceptual en torno a las capacidades terapéuticas de las MSC y un análisis crítico de algunos de los factores, que han impedido que estas sean una opción terapéutica usable en la práctica clínica diaria

Since they were initially identified more than 40 years ago, mesenchymal stem cells (MSCs) were recognized as an important therapeutic alternative for diseases characterized by acute or chronic loss of tissue, thanks to their proliferation and differentiation ability, which would allow the replacement of lost cells and their structural and functional recuperation. Evidence suggesting the therapeutic potential of these cells for a vast group of diseases increases day by day, at least in preclinical experimental models. However, clinical trials have been unable to obtain consistent and categorical results to demonstrate this capacity. This review aims to provide, an overview on the current status of the conceptual development on the therapeutic properties of MSCs, and a critical analysis of some factors which have hindered the application of this therapeutic option in daily clinical practice.

Xeno-Free Extraction, Culture, and Cryopreservation of Human Adipose-Derived Mesenchymal Stem Cells.

Molecules of animal or bacterial origin, which pose a risk for zoonoses or immune rejection, are commonly used for extraction, culture, and cryopreservation of mesenchymal stem cells. There is no sequential and orderly protocol for producing human adipose-derived stem cells (hASCs) under xeno-free conditions. After standardizing a human platelet lysate (hPL) production protocol, four human adipose tissue samples were processed through explants with fetal bovine serum (FBS)-supplemented or hPL-supplemented media for extracting the adipose-derived stem cells. The cells were cultivated in cell culture medium + hPL (5%) or FBS (10%). The cellular replication rate, immunophenotype, and differentiation potential were evaluated at fourth passage. Cellular viability was evaluated before and after cryopreservation of the cells, with an hPL-based solution compared with an FBS-based solution. The explants cultured in hPL-supplemented media showed earlier and faster hASC proliferation than did those supplemented with FBS. Likewise, cells grown in hPL-supplemented media showed a greater proliferation rate, without losing the immunophenotype. Osteogenic differentiation of xeno-free hASC was higher than the hASC produced in standard conditions. However, adipogenic differentiation was reduced in xeno-free hASC. Finally, the cells cryopreserved in an hPL-based solution showed a higher cellular viability than the cells cryopreserved in an FBS-based. In conclusion, we have developed a complete xeno-free protocol for extracting, culturing, and cryopreserving hASCs that can be safely implemented in clinical studies.