Intestinal fructose transporters GLUT5 and GLUT2 in children and adolescents with obesity and metabolic disorders

Purpose: The excessive fructose intake including high-fructose corn syrup (HFCS) may be responsible for increase of obesity occurrence. This study was designed to find potential differences in duodenal fructose transporters on mRNA and protein levels between obese and normal weight children and adolescents. Materials/methods: We performed a cross-sectional study on a group of 106 hospitalized patients aged 12 to 18. Glucose transporter 2 (GLUT2) and glucose transporter 5 (GLUT5) mRNA as well as protein levels (ELISA and Western blot methods) were assessed in duodenal mucosa biopsies of the patients categorized as obese or normal weight. Additionally, the expression of the aforementioned transporters was analyzed in patients based on the presence of insulin resistance (IR) and metabolic syndrome (MS). Results: In children with obesity, increased duodenal protein levels of GLUT5 (Relative protein GLUT5 expression/ ACTB) (0.027 f 0.009 vs. 0.011 f 0.006, p < 0.05) but not GLUT2 as compared with the normal weight group, were revealed. No significant differences in duodenal relative GLUT2 and GLUT5 genes expression between the studied groups were found. There was no relationship between the presence of IR or MS and intestinal mRNA GLUT2 and GLUT5 as well as GLUT2 protein expression. Conclusion: The upregulation of the duodenal GLUT5 may contribute to obesity occurrence in children and adolescents.