Résumé
Patients with rheumatoid arthritis (RA) have an altered gut microbiota (dysbiosis) (1-3). This microbiota interacts with intestinal epithelium which can lead to an increased intestinal permeability, responsible for the passage of antigens and inflammatory molecules, and can therefore promote systemic inflammation. Gut microbiota tends to normalize with disease control (2), suggesting that systemic inflammation may directly influence the composition of microbiota and the gut barrier. It was shown in many inflammatory diseases that intestinal permeability is impaired, but to date there is very little data in RA.
In the present study, we evaluate the intestinal permeability in RA patients by analyzing tight junctions in colonic biopsies and serum markers.
Colonic biopsies from 20 RA patients who underwent coloscopy for screening with normal histology were compared with those from 20 age and sex matched controls. ZO-1, occludin and claudin 2 junction proteins were evaluated by immunohistochemistry. The staining intensity was assessed by two blinded independent readers. The serum concentrations of LPS-binding protein (LBP), CD14s and zonulin were evaluated by ELISA in 25 patients naive of DMARDs, 41 patients before and after introduction of a DMARDs and 21 controls. Elevated zonulin in serum indicates an increase in intestinal permeability while LBP and CD14s indicate bacterial translocation.
ZO-1 expression was significantly lower in biopsies from patients with RA than controls (mean score ± SD of 1.6 ± 0.56 vs 2.0 ± 0.43; p = 0.01). Age, sex, disease duration and immunological status did not significantly influence the expression of colonic junction proteins. LBP and CD14s were higher in serum from RA patients naive of DMARDs than controls (p = 0.002 and p = 0.003). LBP, CD14s and zonulin levels significantly correlated with DAS28 (r = 0.61, p = 0.005; r = 0.51, p = 0.030 and r = 0.46, p = 0.049, respectively). After treatment, unlike non-responders, LBP and CD14s were significantly reduced in DMARD responders and variations in LBP and CD14s significantly correlated with changes in DAS28 (r = 0.46, p = 0.002 and r = 0, 33 and p = 0.030, respectively).
This work is one of the first to explore intestinal permeability in RA and to show altered tight junction in colonic tissue from RA. This increased intestinal permeability appears to be related to the systemic inflammation. Improving the gut microbiota through food or probiotics could enhance the effect of treatments by limiting this amplification loop of inflammation.
[1]Horta-Baas G, Romero-Figueroa MDS, Montiel-Jarquin AJ, Pizano-Zarate ML, Garcia-Mena J, Ramirez-Duran N. Intestinal Dysbiosis and Rheumatoid Arthritis: A Link between Gut Microbiota and the Pathogenesis of Rheumatoid Arthritis. J Immunol Res. 2017;2017:4835189.
[2]Zhang X, Zhang D, Jia H, Feng Q, Wang D, Liang D, et al. The oral and gut microbiomes are perturbed in rheumatoid arthritis and partly normalized after treatment. Nat Med. 2015;21(8):895-905.
[3]Maeda Y, Kurakawa T, Umemoto E, Motooka D, Ito Y, Gotoh K, et al. Dysbiosis Contributes to Arthritis Development via Activation of Autoreactive T Cells in the Intestine. Arthritis Rheumatol. 2016;68(11):2646-61.
Rachel Audo: None declared, Pauline Sanchez: None declared, Julie Mielle: None declared, Laurence Macia: None declared, Benjamin Rivière: None declared, Cédric Lukas: None declared, Bernard Combe: None declared, Jacques Morel: None declared, Claire Daien Speakers bureau: Pfizer roche chugai fresenius BMS msd Novartis galapagos, Consultant of: Abivax abbbvie BMS roche chugai, Grant/research support from: Pfizer, roche-chugai, fresenius, msd