Fasting-Mimicking Diet Modulates Microbiota and Promotes Intestinal Regeneration to Reduce Inflammatory Bowel Disease Pathology

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Immunoglobulin A Targets a Unique Subset of the Microbiota in Inflammatory Bowel Disease

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益生菌在炎症性肠病中的治疗作用

炎症性肠病(inflammatory bowel disease,IBD)包括溃疡性结肠炎(ulcerative colitis,UC)和克罗恩病(Crohn’s disease,CD)。随着对肠道微生物群在IBD发病机制中作用的认识不断深入,近年来益生菌广泛应用于IBD治疗。大量临床试验结果表明,益生菌治疗IBD的疗效主要体现在对UC和贮袋炎的治疗,对CD的疗效不明确。益生菌治疗IBD可能通过促进肠道微生物群平衡、改善肠道屏障功能、调节肠道黏膜免疫及营养物质代谢等途径。     

Targeted suppression of human IBD-associated gut microbiota commensals by phage consortia for treatment of intestinal inflammation

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Interleukin 35 (IL-35) and IL-37: Intestinal and peripheral expression by T and B regulatory cells in patients with Inflammatory Bowel Disease

The aim of the study was to characterize and to quantify peripheral and tissue. IL-35— and IL-37—producing cells in Inflammatory Bowel Disease (IBD) patients. We studied a total of 38 active UC, 31 inactive UC, 17 active CD, and 13 inactive CD and 50 non-inflamed tissues as control group. Gene expression was measured by real time polymerase chain reaction (RT-PCR) and protein expression was evaluated in tissue by immunohistochemistry and in peripheral blood mononuclear cells by flow cytometry. Higher levels of IL-35 was produced by intestinal regulatory B cells and circulating regulatory CD4⁺ and CD8⁺ T cells in active vs. inactive disease or healthy donors (P < 0.05). The IL-37 was conspicuously synthesized by circulating B cells, active natural killer cells and monocytes. These results suggest that down-regulation of inflammation in active IBD patients might be based on the increased expression of IL-35 and IL-37.     

Endothelial Fas-Ligand in Inflammatory Bowel Diseases and in Acute Appendicitis

Fas-mediated induction of apoptosis is a major factor in the selection of lymphocytes and downregulation of immunological processes. In the present study, we have assessed endothelial Fas-ligand (FasL) expression in normal human ileum, appendix, and colon, and compared the expression levels with that in inflammatory bowel disease and in acute appendicitis. In a normal appendix, endothelial FasL levels were constant in almost half of the mucosal vessels; but, in the normal ileum and colon, endothelial FasL was practically restricted to areas in close proximity to lymphatic follicles, and was expressed mainly in the submucosal aspect of the follicles in the vessels with high endothelium. In samples from subjects with either Crohn’s disease or ulcerative colitis, the extent of endothelial FasL expression was elevated in the submucosa and associated with an elevated number of lymphoid follicles. In inflammatory bowel disease, ulcers and areas with a high density of mononuclear cells expressing FasL also showed an elevated density of blood vessels with endothelial FasL expression. Although the function of endothelial FasL remains unclear, such a specific expression pattern suggests that endothelial FasL expression has a role in the regulation of lymphocyte access to the peripheral lymphoid tissues, including the intestinal mucosa.     

芍药甘草汤通过调节NDUFS1表达抑制巨噬细胞向M1极化缓解小鼠溃疡性结肠炎

目的 本研究旨在探索并阐明芍药甘草汤（Shakuyakukanzoto,SKT）通过调节巨噬细胞的能量代谢和极化来改善小鼠溃疡性结肠炎（ulcerative colitis,UC）的可能作用机制。方法 通过给予3%葡聚糖硫酸钠盐（dextran sulfate sodium salt,DSS）构建小鼠UC模型并通过灌胃SKT进行治疗。首先,对两个数据集GSE21157和GSE210415进行单细胞测序分析和代谢通路富集。其次,对UC小鼠腹腔巨噬细胞的提取和代谢组学验证。然后,根据标准逆方差加权两样本的单变量孟德尔随机化分析差异代谢物富集的通路和UC风险相关性。接着,分析在GSE128682和GSE102746数据集转录水平差异。最后,使用定量反转录PCR（qRT-PCR）、蛋白质印迹法（Western blot）和流式细胞术验证结果。结果 苏木精-伊红（HE）染色结果显示,SKT可以显著缓解DSS引起的结肠损伤。单细胞测序分析在肠壁中发现了巨噬细胞、NK细胞、T细胞等10多种不同类型的细胞。在疾病组中,通过比较这两组数据发现,有49条主要涉及能量代谢的巨噬细胞代谢途径的活性显著上调。能量代谢组学中,治疗组与模型组,模型组与空白组分别鉴定了10种和18种显著上调和下调的差异表达代谢物,这些差异表达的代谢物主要与糖酵解和氧化磷酸化有关。根据标准逆方差加权两样本的单变量孟德尔随机化分析,预测糖酵解和氧化磷酸化相关基因泛醌NADH脱氢酶Fe-S蛋白1（recombinant NADH dehydrogenase ubiquinone Fe-S protein 1,NDUFS1）（OR：0.56,95% CI：0.48~0.98,P=0.000 068）与UC风险降低相关。通过对两组数据集转录水平差异分析,与正常组相比,UC中NDUFS1的转录水平降低。qRT-PCR、Western blot和流式细胞术验证结果显示,SKT可以促进NDUFS1蛋白的表达,抑制巨噬细胞向M1型极化。此外,敲低/过表达NDUFS1可以影响SKT对巨噬细胞M1型极化的影响。结论 SKT通过调节NDUFS1蛋白水平,抑制巨噬细胞向M1型极化,从而缓解小鼠UC。这些发现不仅揭示了SKT对UC的治疗机制,也为临床应用提供了新的理论基础。     

炎症性肠病小鼠模型的建立及其影响因素探讨

目的:通过单次灌肠和皮肤致敏联合灌肠,构建2,4,6-三硝基苯磺酸(TNBS)诱导的炎症性肠病小鼠模型,探讨最佳造模方法,并分析影响模型构建的因素。方法:55只SPF雄性BALB/c小鼠随机分为7组,包括对照组、不同剂量TNBS(100、150、175、200、225 mg/kg)单次灌肠组及皮肤致敏联合灌肠组。于造模后5 d处死各组小鼠,观察结肠大体形态并评分;取病变处进行石蜡包埋切片,HE染色,并进行病理组织学评分。结果:100、150 mg/kg TNBS单次灌肠组动物未见明显的溃疡形成;其余剂量组动物均有不同程度的溃疡形成,成模率与剂量成正比,其中225 mg/kg剂量组动物成模率为100%,但病变较重、病变不均一且偶有小鼠眼睛失明的副作用出现。皮肤致敏联合灌肠组动物均有溃疡形成,成模率100%,病变适中且未发现小鼠眼睛失明的副作用。结论:175-225 mg/kg TNBS单次灌肠及皮肤致敏联合TNBS灌肠均可制备小鼠炎症性肠病模型,但皮肤致敏联合TNBS灌肠制备的炎症性肠病模型成模率高,病变适中,模型稳定,适合用作科学研究模型。     

白介素23 及Th17 细胞在炎症性肠病的作用

炎症性肠病(Inflammatory Bowel Diseases,IBD),是一组病因未明的累及胃肠道的慢性炎症性疾病,一般指克罗恩病(Crohn’sdisease,CD)和溃疡性结肠炎(ulcerative colitis,UC)。目前认为它是由多种因素相互作用所致的一种自身免疫性疾病,主要包括免疫、环境以及遗传等因素,其中免疫在IBD的发生过程中起着极其重要的作用。以往研究认为与T辅助细胞(T Helper cells)Th1或Th2细胞反应的增强或减弱有关。然而最近研究发现一类新细胞亚群,称为Th17细胞,与之相关的细胞因子可导致包括肠道在内的多脏器病变。Th17细胞分化过程中又需要IL-23的参与,因此IL-23/Th17细胞在炎症性肠病患者肠道内过度表达可以解释肠组织损伤的新途径,并为制定新的治疗策略提出依据。本文就IL-23/Th17轴在炎症性肠病中的作用的研究进展作一综述。     

MicroRNA-193a-3p Reduces Intestinal Inflammation in Response to Microbiota via Down-regulation of Colonic PepT1

Intestinal inflammation is characterized by epithelial disruption, leading to the loss of barrier function, recruitment of immune cells, and host immune responses to gut microbiota. PepT1, a di/tripeptide transporter that uptakes bacterial products, is up-regulated in inflamed colon tissue, which implies its role in bacterium-associated intestinal inflammation. Although microRNA (miRNA)-mediated gene regulation has been found to be involved in various processes of inflammatory bowel disease (IBD), the biological function of miRNAs in the pathogenesis of IBD remains to be explored. In this study we detected miRNA expression patterns in colon tissues during colitis and investigated the mechanism underlying the regulation of colonic PepT1 by miRNAs. We observed an inverse correlation between PepT1 and miR-193a-3p in inflamed colon tissues with active ulcerative colitis, and we further demonstrated that miR-193a-3p reduced PepT1 expression and activity as a target gene and subsequently suppressed the NF-κB pathway. Intracolonic delivery of miR-193a-3p significantly ameliorated dextran sodium sulfate-induced colitis, whereas the overexpression of colonic PepT1 via PepT1 3′-untranslated region mutant lentivirus vector abolished the anti-inflammatory effect of miR-193a-3p. Furthermore, antibiotic treatment eliminated the difference in the dextran sodium sulfate-induced inflammation between the presence and absence of miR-193a-3p. These findings suggest that miR-193a-3p regulation of PepT1 mediates the uptake of bacterial products and is a potent mechanism during the colonic inflammation process. Overall, we believe miR-193a-3p may be a potent regulator of colonic PepT1 for maintaining intestinal homeostasis.     

CALENDAR OF EVENTS

A synopsis and meta-analysis of studies that investigated the association between genetic variants involved in the homocysteine/folate metabolism pathway and risk of inflammatory bowel disease (IBD) were conducted. Four variants (MTHFR C6TTT, MTHFR A1298C, MTR A2756G and MTRR A66G) showed significant associations in individual studies. In meta-analyses, only the variant MTR A2756G indicated an association with the risk of IBD for the allele contrast and the dominant model (odds ratio (OR) 1.48 (1.12–1.97) and OR 1.55 (1.12–2.15), respectively). The effect sizes for Crohn’s disease and ulcerative colitis were similar to IBD. Cumulative meta-analysis for C677T indicated a downward trend of association as information accumulates.     

Chemokine and cytokine levels in inflammatory bowel disease patients

Crohn’s disease (CD) and ulcerative colitis (UC), two forms of inflammatory bowel disease (IBD), are chronic, relapsing, and tissue destructive lesions that are accompanied by the uncontrolled activation of effector immune cells in the mucosa. Recent estimates indicate that there are 1.3 million annual cases of IBD in the United States, 50% of which consists of CD and 50% of UC. Chemokines and cytokines play a pivotal role in the regulation of mucosal inflammation by promoting leukocyte migration to sites of inflammation ultimately leading to tissue damage and destruction. In recent years, experimental studies in rodents have led to a better understanding of the role played by these inflammatory mediators in the development and progression of colitis. However, the clinical literature on IBD remains limited. Therefore, the aim of this study was to evaluate systemic concentrations of key chemokines and cytokines in forty-two IBD patients with a range of disease activity compared to levels found in ten healthy donors. We found a significant increase in an array of chemokines including macrophage migration factor (MIF), CCL25, CCL23, CXCL5, CXCL13, CXCL10, CXCL11, MCP1, and CCL21 in IBD patients as compared to normal healthy donors (P < 0.05). Further, we also report increases in the inflammatory cytokines IL-16, IFN-γ, IL-1β and TNF-α in IBD patients when compared to healthy donors (P < 0.05). These data clearly indicate an increase in circulating levels of specific chemokines and cytokines that are known to modulate systemic level through immune cells results in affecting local intestinal inflammation and tissue damage in IBD patients. Blockade of these inflammatory mediators should be explored as a mechanism to alleviate or even reverse symptoms of IBD.     

Autoimmunity against type VII collagen in inflammatory bowel disease

Autoimmunity against type VII collagen, an adhesion molecule of the extracellular matrix in epithelial basement membranes, is causing the rare organ-specific epidermolysis bullosa acquisita (EBA). An intriguing association between EBA and inflammatory bowel disease (IBD) has been extensively documented over the last decades, but, because of the very low incidence of EBA, received little attention from physicians involved in the care of patients with IBD. More recently, autoantibodies against type VII collagen have been detected in up to 68% of IBD patients. Although these findings suggest that chronic intestinal inflammation in IBD predisposes for autoimmunity against type VII collagen, their relevance for the pathogenesis of both IBD and EBA is still unclear. In this review article, the main features of the association between IBD and EBA are presented and pathomechanistic hypotheses as well as future lines of investigation in this area are discussed. Future research should provide new pathomechanistic insights and will likely facilitate the development of more specific and effective immunotherapeutic strategies for both conditions.     

B Cell Diversification Is Uncoupled from SAP-Mediated Selection Forces in Chronic Germinal Centers within Peyer’s Patches

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Increased TERC gene copy number and cells in senescence in primary sclerosing cholangitis compared to colitis and control patients

Objective

Primary sclerosing cholangitis (PSC) is a chronic cholestatic disorder that involves inflammatory and fibrotic changes in the bile ducts. Up to 80% of patients have concomitant inflammatory bowel disease (IBD) with colitis. PSC patients are predisposed to develop hepatobiliary, colonic and other extrahepatic malignancies, probably related to inflammatory processes that might promote carcinogenesis. Telomerase is an enzyme complex that lengthens telomeres and has enhanced expression in numerous malignancies. In this study, we evaluated the TERC gene copy number, the proportion of cells in senescence and the amount of fragmentation in the senescent state.

Methods

Fluorescence in situ hybridization (FISH) for the TERC gene was applied to lymphocytes retrieved from PSC (N = 19), colitis (N = 20) and healthy control patients (N = 20) to determine the TERC copy number. On the same FISH slides, cells stained with DAPI were also analyzed for senescence-associated heterochromatin foci (SAHF) status, including the number of cells with fragments and the number of SAHF fragments in each cell.

Results

A higher TERC gene copy number was observed in cells from PSC patients compared to colitis and control group patients. It was also higher in the colitis than in the control group. Significantly more cells in the senescent state and more fragmentation in each cell were observed in the PSC group compared to colitis and control groups.

Conclusion

The TERC gene copy number and the number of cells in the senescent state were increased in PSC patients compared to the colitis and control groups. These findings are probably related to the genetic instability parameters that reflect the higher tendency of this patient group to develop malignancies.