Department of Clinical Medicine and Centre for Applied Biomedical Research, University of Bologna, Bologna, Italy.
J Clin Gastroenterol. 2012 Oct;46 Suppl:S52-5. doi: 10.1097/MCG.0b013e318264e918.
There is increasingly convincing evidence supporting the participation of the gut microenvironment in the pathophysiology of irritable bowel syndrome (IBS). Studies particularly suggest an interplay between luminal factors (eg, foods and bacteria residing in the intestine), the epithelial barrier, and the mucosal immune system. Decreased expression and structural rearrangement of tight junction proteins in the small bowel and colon leading to increased intestinal permeability have been observed, particularly in postinfectious IBS and in IBS with diarrhea. These abnormalities are thought to contribute to the outflow of antigens through the leaky epithelium, causing overstimulation of the mucosal immune system. Accordingly, subsets of patients with IBS show higher numbers and an increased activation of mucosal immunocytes, particularly mast cells. Immune factors, released by these cells, including proteases, histamine, and prostanoids, participate in the perpetuation of the permeability dysfunction and contribute to the activation of abnormal neural responses involved in abdominal pain perception and changes in bowel habits. All these mechanisms represent new targets for therapeutic approaches in IBS. Probiotics are an attractive therapeutic option in IBS given their recognized safety and by virtue of positive biological effects they can exert on the host. Of importance for the IBS pathophysiology is that preclinical studies have shown that selective probiotic strains exhibit potentially useful properties including anti-inflammatory effects, improvement of mucosal barrier homeostasis, beneficial effects on intestinal microbiota, and a reduction of visceral hypersensitivity. The effect of probiotics on IBS is positive in most randomized, controlled studies, although the gain over the placebo is small. Identifying tailored probiotic approaches for subgroups of IBS patients represents a challenge for the future.
越来越多的证据支持肠道微环境参与肠易激综合征（IBS）的病理生理学。研究特别表明腔室因素（例如，存在于肠道中的食物和细菌）、上皮屏障和黏膜免疫系统之间存在相互作用。观察到小肠和结肠中的紧密连接蛋白表达减少和结构重排，导致肠道通透性增加，特别是在感染后 IBS 和腹泻型 IBS 中。这些异常被认为导致抗原通过渗漏的上皮流出，引起黏膜免疫系统过度刺激。相应地，IBS 的亚组患者表现出更高数量和更高的黏膜免疫细胞（特别是肥大细胞）的激活。这些细胞释放的免疫因子，包括蛋白酶、组胺和前列腺素，参与了通透性功能障碍的持续存在，并有助于参与腹痛感知和肠道习惯改变的异常神经反应的激活。所有这些机制都代表了 IBS 治疗方法的新靶点。鉴于益生菌的公认安全性以及它们对宿主产生的积极生物学效应，益生菌是治疗 IBS 的一种有吸引力的治疗选择。对于 IBS 的病理生理学很重要的是，临床前研究表明，选择性益生菌菌株具有潜在有用的特性，包括抗炎作用、改善黏膜屏障稳态、对肠道微生物群的有益影响以及降低内脏敏感性。益生菌对 IBS 的影响在大多数随机对照研究中是积极的，尽管与安慰剂相比获益较小。为 IBS 患者的亚组确定量身定制的益生菌方法是未来的挑战。
