The goal of this study was to evaluate how glucose and fructose affected the adipose differentiation of pig newborn mesenchymal stem cells (MSCs). Cells were grown with or without inosine in 7.5 mM glucose (substituted with 1.5 or 6 mM fructose). MSCs displayed adipose morphology after 70 days of differentiation. Fructose stimulated the highest levels of PPARγ and C/EBPβ. Fructose at 6 mM, but not glucose at 7.5 mM or fructose at 1.5 mM, promotes differentiation of MSCs into adipocytes and increases 11-hydroxysteroid dehydrogenase (11β-HSD1) and NADPH oxidase 4 (NOX4) mRNA in the absence of hepatic effects (as simulated by the inosine). Fructose and glucose increased xanthine oxide-reductase (XOR) catalytic activity almost 10-fold and elevated their products: intracellular reactive oxygen species (ROS) pool, extracellular H2 O2 pool by 4 orders of magnitude, and uric acid by a factor of 10. Therefore, in our experimental model, differentiation of MSCs into adipocytes occurs exclusively at the blood concentration of fructose detected after ingestion by people on a high fructose diet. PRACTICAL APPLICATIONS: The results of this study provide new evidence for fructose's adipogenic potential in mesenchymal stem cells, a model in which its effects on XOR activity had not been studied. The increased expression of genes such as C/EBPβ, PPARγ, and NOX4, as well as the increased XOR activity and high production of ROS during the differentiation process in the presence of fructose, coincides in pointing to this hexose as an important factor in the development of adipogenesis in young animals, which could have a great impact on the development of future obesity.
Keywords: adipogenesis; fructose; glucose; inosine; mesenchymal stem cells; reactive oxygen species.
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