Human adipose tissue-derived stem cells cultured in xeno-free culture condition enhance c-MYC expression increasing proliferation but bypassing spontaneous cell transformation.

INTRODUCTION: Human adipose tissue-derived stem cells (hASCs) are attractive cells for therapeutic applications and are currently being evaluated in multiple clinical trials. Prior to their clinical application, hASCs must be expanded ex vivo to obtain the required number of cells for transplantation. Fetal bovine serum is the supplement most widely used for cell culture, but it has disadvantages and it is not safe for cell therapy due to the risks of pathogen transmission and immune reaction. Furthermore, the cell expansion poses a risk of accumulating genetic abnormalities that could lead to malignant cell transformation. In this study, our aim was to evaluate the proliferation pattern as well as the resistance to spontaneous transformation of hASCs during expansion in a xeno-free culture condition. METHODS: hASCs were expanded in Dulbecco's modified Eagle's medium supplemented with pooled allogeneic human serum or fetal bovine serum to enable a side-by-side comparison. Cell viability and differentiation capacity toward the mesenchymal lineages were assessed, along with immunophenotype. Ki-67 expression and the proliferation kinetics were investigated. The expression of the transcription factors c-FOS and c-MYC was examined with Western blot, and MYC, CDKN2A, ERBB2 and TERT gene expression was assessed with quantitative PCR. Senescence was evaluated by ß-gal staining. Karyotype analysis was performed and tumorigenesis assay in vivo was also evaluated. RESULTS: The hASCs expanded in medium with pooled allogeneic human serum did not show remarkable differences in morphology, viability, differentiation capacity or immunophenotype. The main difference observed was a significantly higher proliferative effect on hASCs cultured in pooled allogeneic human serum. There was no significant difference in C-FOS expression; however, C-MYC protein expression was enhanced in pooled allogeneic human serum cultures compared to fetal bovine serum cultures. No difference was observed in MYC and TERT mRNA levels. Moreover, the hASCs presented normal karyotype undergoing senescence, and did not form in vivo tumors, eliminating the possibility that spontaneous immortalization of hASCs had occurred with pooled allogeneic human serum. CONCLUSIONS: This complete characterization of hASCs cultivated in pooled allogeneic human serum, a suitable xeno-free approach, shows that pooled allogeneic human serum provides a high proliferation rate, which can be attributed for the first time to C-MYC protein expression, and showed cell stability for safe clinical applications in compliance with good manufacturing practice.

Fundamentos teórico-clínicos del enfoque sistémico en odontología infantil / Theoretical-clinical fundamentals of the systemic approach in pediatric dentistry

El objetivo de este trabajo fue transmitir las bases filosóficas y epidemiológicas de un método clínico en odontopediatría, el cual permite a una enorme mayoría de los pacientes niños acceder al tratamiento completo de patologías complejas. Postulamos que el Sistema Odontológico Terapéutico se basa en un contrato no escrito, que es verbal y no verbal, y proponemos una serie de reglas para este contrato, con el objeto de optimizar la calidad de las relaciones entre los participantes. Definimos aspectos necesarios de los roles de los padres, del niño y del profesional, y aportamos elementos actualizados para el uso reflexivo de las distintas escalas de evolución infantil producidas en el siglo XX

Construyendo una clínica sistemática en odontología infantil / Building up a systematic clinics in pediatric dentistry

En este artículo, un equipo integrado por una odontopediatra y una terapeuta familiar describe la consulta y tratamiento en odontopediatría como un sistema terapéutico con características específicas. Se postula que el dentista de niños puede participar de la resolución de problemas en este contexto (temores del niño y/o de la familia) de manera tal que el proceso enriquezca aspectos del esquema corporal del niño, aumente las alternativas para los vínculos familiares y estimule la acción autónoma de la familia para el cuidado de la salud bucal y de la salud en general