Ciccia Francesco, Guggino Giuliana, Rizzo Aroldo, Alessandro Riccardo, Luchetti Michele Maria, Milling Simon, Saieva Laura, Cypers Heleen, Stampone Tommaso, Di Benedetto Paola, Gabrielli Armando, Fasano Alessio, Elewaut Dirk, Triolo Giovanni
Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Reumatologia, University of Palermo, Palermo, Italy.
UOC di Anatomia Patologica, Ospedali riuniti villa Sofia-Cervello, Palermo, Italy.
Ann Rheum Dis. 2017 Jun;76(6):1123-1132. doi: 10.1136/annrheumdis-2016-210000. Epub 2017 Jan 9.
Dysbiosis has been recently demonstrated in patients with ankylosing spondylitis (AS) but its implications in the modulation of intestinal immune responses have never been studied. The aim of this study was to investigate the role of ileal bacteria in modulating local and systemic immune responses in AS.
Ileal biopsies were obtained from 50 HLA-B27 patients with AS and 20 normal subjects. Silver stain was used to visualise bacteria. Ileal expression of tight and adherens junction proteins was investigated by TaqMan real-time (RT)-PCR and immunohistochemistry. Serum levels of lipopolysaccharide (LPS), LPS-binding protein (LPS-BP), intestinal fatty acid-BP (iFABP) and zonulin were assayed by ELISA. Monocyte immunological functions were studied in in vitro experiments. In addition the effects of antibiotics on tight junctions in human leukocyte antigen (HLA)-B27 transgenic (TG) rats were assessed.
Adherent and invasive bacteria were observed in the gut of patients with AS with the bacterial scores significantly correlated with gut inflammation. Impairment of the gut vascular barrier (GVB) was also present in AS, accompanied by significant upregulation of zonulin, and associated with high serum levels of LPS, LPS-BP, iFABP and zonulin. In in vitro studies zonulin altered endothelial tight junctions while its epithelial release was modulated by isolated AS ileal bacteria. AS circulating monocytes displayed an anergic phenotype partially restored by ex vivo stimulation with LPS+sCD14 and their stimulation with recombinant zonulin induced a clear M2 phenotype. Antibiotics restored tight junction function in HLA-B27 TG rats.
Bacterial ileitis, increased zonulin expression and damaged intestinal mucosal barrier and GVB, characterises the gut of patients with AS and are associated with increased blood levels of zonulin, and bacterial products. Bacterial products and zonulin influence monocyte behaviour.
最近在强直性脊柱炎（AS）患者中发现了肠道菌群失调，但其对肠道免疫反应调节的影响尚未得到研究。本研究旨在探讨回肠细菌在调节AS患者局部和全身免疫反应中的作用。
从50例HLA - B27阳性的AS患者和20名正常受试者中获取回肠活检组织。用银染法观察细菌。通过TaqMan实时（RT）-PCR和免疫组织化学研究紧密连接蛋白和黏附连接蛋白在回肠中的表达。采用酶联免疫吸附测定法（ELISA）检测血清中脂多糖（LPS）、LPS结合蛋白（LPS - BP）、肠脂肪酸结合蛋白（iFABP）和闭合蛋白的水平。在体外实验中研究单核细胞的免疫功能。此外，评估了抗生素对人白细胞抗原（HLA）-B27转基因（TG）大鼠紧密连接的影响。
在AS患者的肠道中观察到黏附性和侵袭性细菌，细菌评分与肠道炎症显著相关。AS患者还存在肠道血管屏障（GVB）受损，同时闭合蛋白显著上调，并与血清中高浓度的LPS、LPS - BP、iFABP和闭合蛋白相关。在体外研究中，闭合蛋白改变内皮细胞紧密连接，而其上皮释放受AS回肠分离细菌的调节。AS循环单核细胞表现出无反应性表型，经LPS + sCD14体外刺激可部分恢复，用重组闭合蛋白刺激可诱导明显的M2表型。抗生素可恢复HLA - B27 TG大鼠的紧密连接功能。
细菌性回肠炎、闭合蛋白表达增加、肠黏膜屏障和GVB受损是AS患者肠道的特征，且与血液中闭合蛋白和细菌产物水平升高有关。细菌产物和闭合蛋白影响单核细胞行为。
