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ENHANCEMENT OF GLUTEN-INDUCED EPITHELIAL INJURY BY INDOMETHACIN IN HLA-DQ8/HCD4 TRANSGENIC MICE

J Natividad, J Jury, P-C Yang, M Perdue, EF Verdu
Intestinal Disease Research Program, McMaster University, Canada

Background & AIM: Gluten-sensitive HLA-DQ8/HCD4 mice exhibit neuromuscular and epithelial barrier dysfunction in the absence of mucosal atrophy that characterizes celiac disease (CD). The model allows investigation of pathogenetic mechanisms related to gluten sensitivity in a genetically predisposed host before the onset of a chronic lesion. We tested the hypothesis that modulation of intestinal barrier function by low dose indomethacine (Indo) affects the response to gluten sensitization in the model.
METHOD: Groups of HLA-DQ8 mice studied were: 1) sensitized with 500-µg crude gluten in 50 µl CFA (ip), subsequently gavaged with gluten (2 mg) and Indo (3.4 mg/kg) 3/week for 6 weeks, 2) gluten immunized, gavaged with gluten, 3) non-immunized (CFA), gavaged with Indo, 4) non-immunized controls, gavaged with rice. Small intestinal tissues were mounted in Ussing Chambers and baseline short circuit current (Isc), conductance (G), and macromolecule transport (HRP flux), were measured. Epithelial cell (EC) ultrastructure was assessed by electron microscopy (EM).
RESULTS: Intestinal permeability parameters were more severely affected in the gluten plus Indo treated group (Table 1). Combined Gluten+Indo treatment also led to more severe EC damage, characterized by frequent opening of open tight junctions (tj) (Table 1), altered mitochondria, and microvilli disruption.
                                   

	Controls	Indo	Gluten	Gluten+Indo
Isc (uA/cm2)	20.42 ± 3.0	33.76 ± 3.6a	33.42 ± 4.7a	31.60 ± 5.0a
G (mS/cm2)	24.83 ± 1.3	27.03 ± 2.7	27.77 ± 3.0	31.33 ± 4.1 a
HRP Flux (pmol/cm2/hr)	19.68 ± 1.2	42.43 ± 4.7a	51.15 ± 5.3a	57.60 ± 11.1a,b
Frequency of open tj (%)	4.71 ± 0.4	7.18 ± 0.8	7.01 ± 1.2	10.89 ± 0.7a,b,c

 a p<0.05 vs Controls, b p<0.01 vs Indo, c p<0.01 vs Gluten
CONCLUSION: Altered intestinal permeability potentiates intestinal barrier dysfunction induced by gluten and leads to more severe EC injury. The results suggest environmental insults that affect intestinal barrier function may predispose to more severe clinical expression of gluten sensitivity and contribute to progression of disease.

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