The gut microbiota and inflammatory bowel disease

Seminars in Immunopathology - Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gut. Although the precise cause of IBD remains unknown, the most accepted...     

饮食、肠道菌群与炎症性肠病

炎症性肠病 (Inflammatory Bowel Disease,IBD) 是一种胃肠道的慢性免疫相关性炎症性疾病,目前发病机制尚不十分明确,与遗传因素、机体免疫失调、环境因素 (如饮食) 和肠道菌群等因素均密切相关。目前普遍认为饮食因素和肠道菌群均是IBD发病机制的重要环节,而饮食可以通过改变肠道菌群及其代谢产物调节肠道微生态环境,肠道菌群的改变也能影响饮食的作用效果。本文主要讨论饮食、肠道菌群以及饮食与肠道菌群的相互作用对IBD的影响。     

Differential expression of the TRAIL/TRAIL-receptor system in patients with inflammatory bowel disease

TNF-related apoptosis inducing-ligand (TRAIL) is a potent inducer of apoptosis and plays an important role in immune regulation. To explore the role of TRAIL in inflammatory bowel disease (IBD), we examined the expression of the TRAIL/TRAIL-receptor system in colonic resections from patients with ulcerative colitis and Crohn's disease in comparison to normal colon and appendicitis.     

Quality of life in patients with inflammatory bowel disease

The term 'quality of life' is defined as the result of objective circumstances of life and subjective perceptions of patients. Health-related quality of life is a dynamic concept which changes during an adaptational process interacting with illness condition during the course of chronic inflammatory bowel disease. In a review on the research in this field, it is shown that quality-of-life assessment may be an important adjunct to the evaluation and treatment of patients with inflammatory bowel disease. The comparative evaluation of quality of life in patients treated medically and surgically may offer important information for decision making.     

High endothelial venules associated with T cell subsets in the inflamed gut of newly diagnosed inflammatory bowel disease patients

Naive and central memory T lymphocytes (T_N and T_CM) can infiltrate the inflamed gut mucosa in inflammatory bowel disease (IBD) patients. Homing of these subsets to the gut might be explained by ectopic formation of tertiary lymphoid organs (TLOs), containing high endothelial venules (HEVs). We aimed to evaluate the presence of HEVs and TLOs in inflamed intestinal mucosa of newly diagnosed, untreated IBD patients in relation to the presence of T_N and T_CM lymphocytes. IBD patients (n = 39) and healthy controls (n = 8) were included prospectively. Biopsy samples of inflamed and normal intestine, respectively, were analysed by immunohistochemistry for lymphocytes (CD3/CD20), blood vessels (CD31) and peripheral lymph node addressin (PNAd) expression (MECA‐79). T_N and T_CM lymphocyte subsets were identified by flow cytometric immunophenotyping. A higher number of HEVs was found in the inflamed colon of patients with ulcerative colitis [median 3·05 HEV/mm²; interquartile range (IQR) = 0–6·39] and ileum of Crohn's disease patients (1·40; 0‐4·34) compared to healthy controls (both 0; P = 0·033). A high density of colonic HEVs (HEV^high) was associated with increased infiltration of T_N and T_CM in the inflamed gut (median 87%; IQR = 82–93% of T cell population), compared to HEV^low patients (58%; 38–81%; P = 0·003). The number of colonic follicles was higher in HEV^high patients (median 0·54/mm²; IQR 0·28–0·84) compared to HEV^low patients (0·25/mm²; 0·08–0·45; P = 0·031) and controls (0·31/mm²; 0·23–0·45; P = 0·043). Increased homing of T_N and T_CM lymphocytes to inflamed gut tissue in IBD patients might be facilitated by ectopic formation of extrafollicular HEVs and TLOs in a subgroup of patients.     

Serum IgE levels in patients with inflammatory bowel disease

The role of allergy in the pathogenesis of inflammatory bowel disease (IBD) is unclear. The present study was performed to evaluate serum levels of IgE and other immunoglobulin classes in patients with IBD. Patients with IBD had significantly elevated serum levels of both IgG and IgM in the presence of normal levels of IgA. Serum concentration of IgE, as well as the prevalence of patients with "high IgE" were significantly increased in IBD. Among patients with IBD, those with Crohn's disease or those in relapse had the highest levels of IgE. The possibility that allergy plays a pathogenic role in a subset of IBD is discussed.     

Platelets and anticoagulant capacity in patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are susceptible to thromboembolic complications. Several mechanisms can be responsible, including abnormal regulation of coagulation activity, disturbances of fibrinolysis, inflammatory reactions and thrombocytosis. The aim of this study was to assess hemostatic alterations in these parameters during exacerbation of disease. We studied disease activity in 99 IBD patients receiving anti-inflammatory therapy, in relation to: procoagulant markers, i.e. prothrombin fragment F1 + 2 (F1 + 2), D-dimer and platelet count, anticoagulant markers, i.e. protein C, protein S and antithrombin, and a mediator of inflammation (IL-6). Coagulation activity and platelet count were increased during active disease in IBD patients compared with those in a state of remission. The IL-6 concentrations were positively correlated with disease activity and thrombocytosis in patients with ulcerative colitis, but no association with the anticoagulant capacity could be demonstrated except for a decrease in protein C during high disease activity.     

Role of Helicobacter species in Chinese patients with inflammatory bowel disease

Based on 16S rRNA gene PCR, no significant difference was observed in rates of detection of Helicobacter species in intestinal biopsy specimens from 160 Chinese inflammatory bowel disease (IBD) patients (10%) and 80 controls (6.3%). By using a [(13)C]urea breath test, the H. pylori infection rate in 208 Chinese IBD patients (19.7%) was found to be significantly lower than that in 416 controls (48.8%).     

Increased frequency of bronchial hyperresponsiveness in patients with inflammatory bowel disease

Although bronchopulmonary manifestations are rare in inflammatory bowel diseases (IBD), subclinical abnormalities have been described in up to 50% of cases. The pathophysiology of these abnormalities remains unknown. However, a latent inflammation of the bronchial mucosa secondary to the inflammation of the intestinal mucosa has been suggested. This subclinical inflammation may lead to increased bronchial responsiveness. We studied the bronchial responsiveness in 38 inflammatory bowel disease (IBD) patients, using the methacholine test. Bronchial hyperresponsiveness was defined by a PC₂₀M <16 mg/ml. Twenty-four healthy controls were also studied. There was no significant difference in baseline FEV₁ between IBD patients and controls. However, there was a significantly greater fall in FEV₁ in the IBD patients at the concentrations of methacholine tested. The frequency of bronchial hyperresponsiveness was significantly higher in the IBD population (45%) than in controls (17%; P <0.03). Atopy, defined by skin test, was more common in IBD patients (42%) than in controls (21%). Even when only nonatopic subjects were considered, the frequency of bronchial hyperresponsiveness was significantly higher in IBD patients (41%) than in controls (5%; P <0.02). Thus, subclinical bronchial hyperresponsiveness is common in IBD, and may be considered a further extraintestinal manifestation.     

Altered expression of cell adhesion molecules in uninvolved gut in inflammatory bowel disease.

Adhesion of circulating cells to vascular endothelium occurs in the early phase of inflammation, and is mediated by specific cell adhesion molecules. Many such adhesion molecules are increased in inflamed regions of ulcerative colitis (UC) and Crohn's disease (CD) but there is limited knowledge of their expression in the uninvolved gut, adjacent to inflammation. We investigated immunohistochemically the expression of platelet endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) on resected specimens taken at a distance of 2-4 cm from the inflamed area and without histological signs of inflammation. Compared with normal gut, we found (i) a significant increase of PECAM-1-positive vessels in the mucosa of uninvolved UC (149.0 +/- 24.1 vessels/mm2 (mean +/- s.d.); normal colon = 123.1 +/- 21.6; P = 0.004); (ii) a significant decrease of ICAM-1-positive vessels in uninvolved CD (111.9 +/- 22.6 vessels/mm2; normal ileum = 136.9 +/- 27.6; P = 0.04); and (iii) a moderate but statistically insignificant increase of LFA-1-positive cells in the mucosa of uninvolved UC and Crohn's ileitis. This altered expression of cell adhesion molecules may contribute to the early lesion in inflammatory bowel disease and provide new therapeutic opportunities.     

Gene expression in mononuclear cells from patients with inflammatory bowel disease

OBJECTIVES: Discovery of Nod2 as the inflammatory bowel disease 1 (IBD1) susceptibility gene has brought to light the significance of mononuclear cells in inflammatory bowel disease pathogenesis. The purpose of this study was to examine changes in gene expression in peripheral blood mononuclear cells in patients with untreated Crohn's disease (CD) and ulcerative colitis (UC) as compared to patients with other inflammatory gastrointestinal disorders and to healthy controls. METHODS: We used a 2400 gene cDNA glass slide array (MICROMAX) to examine gene expression in peripheral blood mononuclear cells from seven patients with Crohn's disease, five patients with ulcerative colitis, 10 patients with other inflammatory gastrointestinal disorders, and 22 age- and sex-matched controls. Results. Novel categories of genes differentially expressed in Crohn's disease and ulcerative colitis patients included genes regulating hematopoietic cell differentiation and leukemogenesis, lipid raft-associated signaling, the actin cytoskeleton, and vesicular trafficking. Conclusions: Altered gene expression in mononuclear cells may contribute to inflammatory bowel disease pathogenesis.