MESENCHYMAL STEM CELLS FROM AFRICAN AMERICANS DISPLAY GREATER GLUCOSE OXIDATION COMPARED TO STEM CELLS FROM CAUCASIAN INFANTS

Abstract

Background: Type 2 Diabetes and Obesity are more prevalent in African Americans (AA) than Caucasian (C) adults. Associated with this is Metabolic Inflexibility, the inability to switch between substrate usage depending on the physiological demand. Data regarding metabolic differences between racial groups at birth has still not been explored. PURPOSE: The purpose was to discover if there are racial differences in substrate metabolism that is evident at birth utilizing mesenchymal stem cell (MSCs) collected from infant umbilical cords. METHODS: 12 mother-child dyads were included in this study; mesenchymal stem cells were collected from the umbilical cords of 6 AA and 6 C infants. Radio-labeled tracers were used to test differences in fatty acid and glucose metabolism in the differentiated and myogenically differentiated states (a model of infant skeletal muscle). RESULTS: The results from our analysis indicate in myogenic MSCs, the glucose oxidation rate was significantly higher in AA compared to C in both basal (p[less-than-or-equal-to]0.05) and insulin-stimulated (p[less-than-or-equal-to]0.05) states. Interestingly, NOGM production and glucose partitioning were similar between groups in both basal (p[greater-than-or-equal-than]0.05) and insulin-stimulated (p[greater-than-or-equal-than]0.05) states. In contrast to the previously described phenotype in adults, similar relative glycogen synthesis rates were observed between groups (p[greater-than-or-equal-than]0.05). To assess if there is an inherent "metabolic driver" associated with the observed phenotype, we compared the difference between D0 and D21 MSCs. Accordingly, we observed that upon myogenic differentiation, MSCs from AA infants increase glucose oxidation rate significantly more (p[less-than-or-equal-to]0.05) than MSCs from C infants. Further, AA shifts significantly more towards glucose rather than palmitate oxidation upon myogenic differentiation (p[less-than-or-equal-to]0.05) compared to C infants. CONCLUSION: Collectively, these data suggest that there are metabolic differences present at birth between races. Further investigation is needed to address if these differences are influential in the manifestation of metabolic disease disparities observed in adults.