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

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

Simposio; 15th International Celiac Disease Symposium; 2013

Fatty acid binding proteins (FABPs) belong to a family of small cytosolic proteins. 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, and increased in intestinal mucosa in untreated Celiac Disease (CD). 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. The aim of this work was to analyse the pattern of expression of I, L and A-(adipocyte) FABPs in intestinal mucosa in CD. Expression of I, L and AFABP in duodenal tissue sections was assessed by confocal fluorescence microscopy using specific polyclonal antibodies. Immunofluorescence analysis showed a differential pattern of expression for FABPs. Though I and LFABP were expressed in the epithelium in healthy mucosa, intensity of staining was higher in severe enteropathy cases. Both FABPs were also observed in the crypts, though this expression was clearly increased in untreated CD. Remarkably, some mononuclear cells in the lamina propria were also stained for I, L and AFABP. Quantitative PCR analysis showed that mRNA levels for I and LFABP are lower in duodenal samples from adult untreated CD patients than in healthy controls (p<0,01). In contrast, serum levels of iFABP were higher in adult untreated CD patients compared with healthy controls (p<0.007). In conclusion, though higher levels of IFABP in serum samples from CD patients are probably due to the enterocyte damage, the changes observed in FABPs expression in the intestinal mucosa seem a more complex process and may be linked to or be a consequence of the inflammatory process occurring in severe enteropathy and deserve further evaluation.