32 research outputs found

    Proliferation and survival of human amniotic epithelial cells during their hepatic differentiation

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    Stem cells derived from placental tissues are an attractive source of cells for regenerative medicine. Amniotic epithelial cells isolated from human amnion (hAECs) have desirable and competitive characteristics that make them stand out between other stem cells. They have the ability to differentiate toward all three germ layers, they are not tumorigenic and they have immunosuppressive properties. Although liver transplantation is the best way to treat acute and chronic hepatic failure patients, there are several obstacles. Recently, stem cells have been spotlighted as alternative source of hepatocytes because of their potential for hepatogenic differentiation. In this work, we aimed to study the proliferation and survival of the hAECs during their hepatic differentiation. We have also analyzed the changes in pluripotency and hepatic markers. We differentiated amniotic cells applying a specific hepatic differentiation (HD) protocol. We determined by qRT-PCR that hAECs express significant levels of SOX-2, OCT-4 and NANOG during at least 15 days in culture and these pluripotent markers diminish during HD. SSEA-4 expression was reduced during HD, measured by immunofluorescence. Morphological characteristics became more similar to hepatic ones in differentiated cells and representative hepatic markers significantly augmented their expression, measured by qRT-PCR and Western blot. Cells achieved a differentiation efficiency of 75%. We observed that HD induced proliferation and promoted survival of hAECs, during 30 days in culture, evaluated by 3H-thymidine incorporation and MTT assay. HD also promoted changes in hAECs cell cycle. Cyclin D1 expression increased, while p21 and p53 levels were reduced. Immunofluorescence analysis showed that Ki-67 expression was upregulated during HD. Finally, ERK 1/2 phosphorylation, which is intimately linked to proliferation and cell survival, augmented during all HD process and the inhibition of this signaling pathway affected not only proliferation but also differentiation. Our results suggest that HD promotes proliferation and survival of hAECs, providing important evidence about the mechanisms governing their hepatic differentiation. We bring new knowledge concerning some of the optimal transplantation conditions for these hepatic like cells.Fil: Maymo, Julieta Lorena. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Riedel, Rodrigo Nicolas. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Pérez Alcázar, Germán Antonio. Hospital Universitario Virgen Macarena;Fil: Magatti, Marta. Istituto Ospedaliero;Fil: Maskin, Bernardo. Hospital Nacional Professor Dr. Alejandro Posadas; ArgentinaFil: Dueñas, José Luis. Hospital Universitario Virgen Macarena;Fil: Parolini, Ornella. Istituto Ospedaliero;Fil: Sánchez-Margalet, Víctor. Hospital Universitario Virgen Macarena;Fil: Varone, Cecilia Laura. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

    A common polymorphism near the interleukin-6 gene modifies the association between dietary fat intake and insulin sensitivity

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    Cristina Cuda1, Bibiana Garcia-Bailo1,2, Mohamed Karmali1,2, Ahmed El-Sohemy1, Alaa Badawi21Department of Nutritional Sciences, University of Toronto, 2Office of Biotechnology, Genomics and Population Health, Public Health Agency of Canada, Toronto, Ontario, CanadaBackground: Increasing evidence suggests a role for inflammation in the development of type 2 diabetes. Elevated levels of inflammatory cytokines, including interleukin-6, have been associated with insulin resistance, and dietary lipids can increase cytokine production. The objective of this study was to determine whether a single nucleotide polymorphism near the IL6 gene (rs7801406) modifies the relationship between dietary fat and markers of insulin sensitivity.Methods: Subjects were healthy men and women aged 20–29 years from the Toronto Nutrigenomics and Health Study. Dietary intake was estimated using a one-month semiquantitative food frequency questionnaire. Fasting blood samples were taken for genotyping and biomarker measurement.Results: The single nucleotide polymorphism was not associated with any of the measures of insulin sensitivity. However, it modified the relationship between total dietary fat and the homeostasis model assessment of insulin resistance (P = 0.053 for interaction). Total fat intake was positively related to HOMA-IR in individuals homozygous for the G allele (ß = 0.005 ± 0.002, P = 0.03), but not among heterozygotes. There was an inverse relationship between total fat intake and HOMA-IR in individuals who were homozygous for the A allele (β= –0.012 ± 0.006, P = 0.047).Conclusion: These findings suggest that dietary fat influences insulin sensitivity differently depending on genotype.Keywords: interleukin-6, insulin sensitivity, nutrigenomics, dietary fa
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