Increased faecal serine protease activity in diarrhoeic IBS patients: a colonic lumenal factor impairing colonic permeability and sensitivity
Increased faecal serine protease activity in diarrhoeic IBS patients: a colonic lumenal factor impairing colonic permeability and sensitivity
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DOI：
10.1136/gut.2007.140210
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发表时间：
2008-05-01
期刊：
影响因子：
24.5
通讯作者：
Bueno, L.
中科院分区：
文献类型：
--
作者：
Gecse, K.;Roka, R.;Bueno, L.
目的：腹泻型肠易激综合征(IBS-D)以肠腔丝氨酸蛋白酶活性升高为特征。这项研究的目的是(1)探讨丝氨酸蛋白酶活性升高的来源，(2)评估它是否足以引发结肠细胞旁通透性(CPP)和敏感性的改变，以及(3)检测蛋白酶激活的受体-2(PAR-2)激活和信号级联在这一过程中的作用。患者和方法：检测健康受试者和IBS、溃疡性结肠炎和急性感染性腹泻患者的粪便酶活性。在对照组和IBS-D患者的粘膜上清液中暴露后，记录野生型和PAR-2(-/-)小鼠对结直肠球囊扩张的肌电反应，并在Ussing小室的结肠条上评估CPP。结果：IBS-D患者粪便丝氨酸蛋白酶活性比便秘主型IBS(IBS-C)或感染性腹泻患者高3倍，既不是上皮细胞来源，也不是炎性细胞来源，也不与内源性抗蛋白酶活性偶联。从IBS-D患者的粪便上清液在小鼠的粘膜应用引起痛觉异常，并使CPP增加92%，这两种作用都被丝氨酸蛋白酶抑制剂所阻止，并依赖于PAR-2的表达。在小鼠中，结肠暴露于IBS-D患者的上清液中，导致肌球蛋白轻链的磷酸化迅速增加，ZO-1在结肠细胞中的重新分布延迟。结论：IBS-D患者结肠腔内丝氨酸蛋白酶活性升高，诱发了PAR-2介导的小鼠结肠上皮屏障功能障碍和随后的痛觉异常，提示了IBS发病的新的器官背景。
Objectives: Diarrhoea-predominant irritable bowel syndrome (IBS-D) is characterised by elevated colonic lumenal serine protease activity. The aims of this study were (1) to investigate the origin of this elevated serine protease activity, (2) to evaluate if it may be sufficient to trigger alterations in colonic paracellular permeability (CPP) and sensitivity, and (3) to examine the role of the proteinase-activated receptor-2 (PAR-2) activation and signalling cascade in this process.Patients and methods: Faecal enzymatic activities were assayed in healthy subjects and patients with IBS, ulcerative colitis and acute infectious diarrhoea. Following mucosal exposure to supernatants from control subjects and IBS-D patients, electromyographic response to colorectal balloon distension was recorded in wild-type and PAR-2(-/-) mice, and CPP was evaluated on colonic strips in Ussing chambers. Zonula occludens-1 (ZO-1) and phosphorylated myosin light chain were detected by immunohistochemistry.Results: The threefold increase in faecal serine protease activity seen in IBS-D patients compared with constipation-predominant IBS (IBS-C) or infectious diarrhoea is of neither epithelial nor inflammatory cell origin, nor is it coupled with antiprotease activity of endogenous origin. Mucosal application of faecal supernatants from IBS-D patients in mice evoked allodynia and increased CPP by 92%, both of which effects were prevented by serine protease inhibitors and dependent on PAR-2 expression. In mice, colonic exposure to supernatants from IBS-D patients resulted in a rapid increase in the phosphorylation of myosin light chain and delayed redistribution of ZO-1 in colonocytes.Conclusions: Elevated colonic lumenal serine protease activity of IBS-D patients evokes a PAR-2-mediated colonic epithelial barrier dysfunction and subsequent allodynia in mice, suggesting a novel organic background in the pathogenesis of IBS.