Introducción. La sangre de cordón umbilical humana es una alternativa para la obtención de células madre hematopoyéticas; sin embargo, no es clara la expresión conjunta de los antígenos CD34, CD38 y HLA-DR, ni de antígenos embrionarios asociados con este tipo de muestra. Objetivos. Determinar la expresión en membrana de los antígenos CD34, CD38 y HLA-DR, así como de los antígenos embrionarios SSEA-4 (Specific Stage Embryonic Antigen-4) y CD13. Materiales y métodos. El estudio se realizó en muestras de sangre de cordón umbilical obtenidas de ochenta mujeres en estado de gravidez normal a término que asistieron al servicio de ginecobstetricia del Hospital Universitario San Ignacio. Los antígenos se determinaron mediante citometría de flujo. Resultados. El rango de células CD34+ presentes en sangre de cordón umbilical humana fue mayor al 0,2% (p=0,0010): a partir de esta población el rango de CD34+/ CD38-/ HLA-DR-fue de 0,0153% a 0,0234%, de CD34+/CD38+/HLA-DR-fue de 0,0191% a 0,296%, de CD34+/ CD38-/HLA-DR+ fue de 0,0427% a 0,0676%, y de CD34+/CD38+/HLA-DR+ fue de 0,2427% a 0,5117%. La expresión de los antígenos embrionarios SSEA-4 y CD13 se determinó con el mismo método y se encontraron ocho muestras positivas para la expresión de estos antígenos. Conclusiones. El fenotipo que se expresa con mayor frecuencia en sangre de cordón umbilical corresponde a CD34+ CD38+ HLA DR+; además, el hallazgo de antígenos embrionarios podría indicar que en sangre de cordón umbilical humana existen poblaciones celulares con fenotipos similares a los progenitores celulares adultos multipotentes (Multipotent Adult Progenitor Cells) descritos en médula ósea.Palabras clave: células madre hematopoyéticas, citometría de flujo, cordón umbilical, trasplante de células madre. Phenotypical determinants of stem cell subpopulations derived from human umbilical cord bloodIntroduction. Human umbilical cord blood (HUCB) is a common source of hematopoietic progenitor cells; however, coexpression of CD34, CD38 and HLA DR antigens and of embryonic antigens (SSEA-4 and CD13) have not been described in HUCB. Objective. The current study attempted to identify in HUCB the presence of these antigens. Materials and methods. Cord blood samples were obtained from 80 women with normal pregnancies, who were attending the gynecology-obstetrics service of the San Ignacio Hospital, Bogotá (Colombia). The antigens were identified with a FACS Calibur BDO flow cytometer and a cocktail of monoclonal antibodies.Results. The population of CD34+ cells in HUCB was higher than 0.2% (p=0.001). The levels of additional cell subpopulations were as follows: CD34+/CD38-/HLA-DR-0.015%-0.023%, CD34+/CD38+/HLA-DR-0.019%-0.30%, CD34+/CD38-/HLA-DR+-0.043%-0.068% and CD34+/CD38+/HLA-DR-0.24%-0.51%. Eight samples of the eighty were positive for embryonic markers. The most frequent phenotype in HUCB was CD34+ CD38+ HLA DR+.

Mesenchymal stem cells (MSCs) have properties that make them a good model to use in regenerative medicine. MSCs proliferation and differentiation are complex processes involving the activation of several molecules that induces changes in intracellular calcium concentration. Different ion channels are responsible for calcium influx including TRP channels. The present study evaluates the expression and functional activity of TRPM8 channels in human mesenchymal stem cells. Cells were characterized by the expression of the specific surface markers CD90+, CD105+ and CD34− and by the ability to differentiate into adipogenic and osteogenic linage. Western blot, immunocytochemistry and flow cytometry were performed to determine TRPM8 protein expression. Patch clamp recordings and fluorescence imaging with Fluo‐4 AM were used to analyze channel activity. We found that the agonist menthol induces an increase in ionic currents which were incompletely abolished by treatment of the cells with the antagonist BCTC. Changes in intracellular calcium concentration were detected after addition of menthol, suggesting an effect induced by activation of TRPM8 channels. Alizarin red staining showed that the TRPM8 agonist Icilin increased osteogenic differentiation. On the contrary, the TRPM8 antagonist BCTC decreased cell differentiation. These results were confirmed by real time PCR with the marker Alkaline Phosphatase (ALP). Results from this study suggest that the activity of TRPM8 channels in mesenchymal stem cells is related with regulation of osteogenic differentiation.Support or Funding InformationThis work was supported by Departamento Administrativo de Ciencia, Tecnología e Innovación, COLCIENCIAS, Project: Evaluación del papel de canales TRPM8 en la diferenciación de células madre mesenquimales derivadas de tejido adiposo; Grant ID 120365843092.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

El libro se constituye en un aporte a las necesidades, preguntas e incertidumbres que surgen cuando se pretende dejar a un lado la tendencia a concebirlos y moldearlos desde el mundo de los adultos, para emprender un camino diferente, que cambie las perspectivas y miradas que se tiene frente a la niñez, tendiente a la transformación de las acciones de los adultos desde estrategias que abran camino hacia la educación alternativa para esta población.