Differential expression of Fatty Acid Binding Proteins (FABPs) in celiac disease

GARCIA, MARINA; BOTASSO, NATALIA; BONDAR, CONSTANZA; CORSICO, BETINA; CHIRDO, FERNANDO

Encuentro; 27th meeting of Working Group on Prolamin Analysis and Toxicity; 2013

Fatty acid binding proteins (FABPs) belong to a family of small cytosolic proteins. FABPs bind and transport long chain fatty acids but also have important roles in signalling pathways, particularly those related to Peroxisome Proliferator-Activated Receptors (PPAR) which link lipid metabolism and inflammatory process. There are nine isoforms which are differentially expressed in distinct tissues. Intestinal and liver FABPs (I- and L-FABP, respectively) are abundantly expressed in the epithelium of the small intestine. Particularly, their expression was reported primarily restricted to fully differentiated epithelial cells. Expression of L- and I-FABP has been evaluated in small and large intestine by immunofluorescence L-FABP staining was detected in the upper half of the villi along the whole small intestine, while the expression was barely detected in the lower half of the villi and in the crypt. On the other hand, I-FABP staining was visualized in intestinal epithelial cells in the villi and in the crypts in both fetal and adult jejunum. Severe changes at the intestinal mucosa are characteristically observed in untreated Celiac Disease patients. Though there are reports describing the expression of L- and I-FABPs in normal small intestine, their expression was not evaluated in CD enteropathy. In addition, higher levels of I-FABP in serum were found in untreated CD patients compared with non celiac controls. The aim of this work was to assess the expression of L- and I-FABP by quantitative PCR in normal small intestine and in active Celiac Disease as well as to evaluate the determination of I-FABP as biomarker for active CD. In this study we replicated previous findings from other groups showing that serum levels of I-FABP are higher in untreated CD patients. Circulating I-FABP is likely released from the damaged enterocyte in untreated CD patients, suggesting that determination of serum I-FABP can be used as an assessment of mucosal damage and as complementary information in diagnosis and follow up of CD patients. Furthermore, we observed that mRNA levels of I-FABP and L-FABP in small intestine were higher in adult than in pediatric samples and, remarkably, that small intestine of untreated CD adult patients showed a reduction in mRNA levels of I-FABP and L-FABP compared to healthy controls. Lower levels of FABPs may have consequences not only in lipid absorption and metabolism but also in inflammatory pathways as those related to PPARα and g which are active in intestinal mucosa.