The Ala54Thr polymorphism in the fatty acid-binding protein 2 gene leads to higher food intake in Japanese women

Development and characterization of 2-dimensional culture for buffalo intestinal cells

Small intestinal epithelial cells (IEC) play a major role in the absorption of nutrients and toxins. Due to the similarity of genome-wide single copy protein orthologues between cattle and human, establishment of ruminant's primary small IEC culture could be a valuable tool for toxicity studies. Therefore, the current study focused on the development and characterization of buffalo IEC culture, as cattle slaughter is banned in India. The buffalo jejunum fragments were washed consecutively several times in saline, warm phosphate buffered saline (PBS), PBS with 5 mM dithiothreitol, digesting solution and 2% sorbitol in PBS. The cells were cultured on 17 µg/cm² collagen coated plates and transwell plates with serum (2% Fetal bovine serum (FBS) and 10% FBS) and serum-free culture conditions. The cells were differentiated into typical epithelial cobblestone morphology from day 5 onwards in 50% successful cultures. The cultured IEC were characterized by gene expression of epithelial cell markers, cytokeratin and vimentin, and enterocyte markers like villin, zonula occluden (ZO1), fatty acid binding protein 2 (FABP2) and small intestinal peptidase (IP). Based on the morphology and gene expression profile, 10% FBS has been recommended for culturing primary buffalo IEC on collagen coated plates for 10 days. However, 50% of the successful cultures could not show epithelial phenotype on 10% FBS culture conditions even on collagen coated plates. Interestingly, undifferentiated IEC showed an increasing expression of FABP2, IP and ZO1 transcripts compared to differentiated intestinal cells with 10% FBS on collagen plates. Therefore, future studies are needed to understand the role of FABP2, IP and ZO1 in differentiation of buffalo IEC.

Human intestinal fatty acid binding protein 2 expression is associated with fat intake and polymorphisms

The intestinal fatty acid binding protein (FABP2) is involved in lipid metabolism whereby variations in the promoter (haplotypes A/B) and exon 2 (Ala54Thr) are associated with dyslipidemia and insulin resistance. To elucidate which factors determine FABP2 expression in human mucosa, we investigated the association between fat intake, genotypes, biochemical variables, and FABP2 expression. FABP2 gene expression was assessed in duodenal specimens from 100 participants who answered a FFQ and who were genotyped and characterized for traits of metabolic syndrome and further biochemical data. Homozygotes for haplotype A tended to have lower fat intake than B-allele carriers (P = 0.066). Searching for an explanation, we evaluated the orexigenic glucose-dependent insulinotropic polypeptide (GIP) in a subset from the Metabolic Intervention Cohort Kiel. AA homozygotes had lower postprandial GIP concentrations than BB homozygotes. Duodenal FABP2 expression was correlated with (n-3) fatty acid (FA) intake in AA homozygotes (r = 0.49; P = 0.021). It was higher in AA homozygotes than in B-allele carriers after adjustment for (n-3) FA intake (P = 0.049) and was negatively correlated with serum FFA (r = -0.41; P < 0.01). Our data indicate that FABP2 expression depends on (n-3) FA intake and FABP2 genotypes. FABP2 might be involved in regulating food intake and intestinal FA utilization.