肠道微生物对肠道屏障功能完整性的维护机制研究概况

肠道微生物群是一个稳定且复杂的生态系统,可以通过形成菌膜屏障或促进肠道上皮细胞增殖分化等方式形成保护屏障,并在肠道病原菌感染和威胁期间维持和促进免疫稳态中起积极作用。本文重点叙述宿主-肠道微生物相互作用过程中抗病原菌感染的方式,以及肠道微生物参与合成抗菌化合物抵御肠道病原菌入侵和威胁的机制,为调控肠道微生物解决临床胃肠道疾病及其相关症状提供理论参考依据。     

肠黏膜屏障与肠道菌群的相互关系

摘要：人类肠道中微生物群与肠道环境相互作用以维持机体健康。肠黏膜屏障主要由黏液层、肠道菌群、肠道免疫系统和肠上皮细胞本身的完整性等构成。肠道作为直接与大量菌群接触的器官,其屏障功能在肠道健康中的作用尤为显著。肠道菌群与肠道屏障相互作用,保持肠道菌群与肠道屏障相对稳定,肠道菌群参与肠道免疫反应的建立,共同建立机体天然防御系统,在保持肠道免疫的动态平衡中具有重要作用。当两者之间的平衡被打破时,可诱发功能性胃肠病（如肠易激综合征）及免疫相关性疾病（如炎症性肠病）。本文主要阐述肠黏膜屏障与肠道菌群之间的相互关系以及与肠道屏障功能障碍相关的肠道疾病。     

The role of intestinal microbiota and its metabolites in intestinal and extraintestinal organ injury induced by intestinal ischemia reperfusion injury

Intestinal ischemia/reperfusion (I/R) is a common pathophysiological process in clinical severe patients, and the effect of intestinal I/R injury on the patient''s systemic pathophysiological state is far greater than that of primary intestinal injury. In recent years, more and more evidence has shown that intestinal microbiota and its metabolites play an important role in the occurrence, development, diagnosis and treatment of intestinal I/R injury. Intestinal microbiota is regulated by host genes, immune response, diet, drugs and other factors. The metabolism and immune potential of intestinal microbiota determine its important significance in host health and diseases. Therefore, targeting the intestinal microbiota and its metabolites may be an effective therapy for the treatment of intestinal I/R injury and intestinal I/R-induced extraintestinal organ injury. This review focuses on the role of intestinal microbiota and its metabolites in intestinal I/R injury and intestinal I/R-induced extraintestinal organ injury, and summarizes the latest progress in regulating intestinal microbiota to treat intestinal I/R injury and intestinal I/R-induced extraintestinal organ injury.     

益生菌抑制肠道慢性炎症及维持肠道稳态的研究进展

益生菌在维护健康和预防疾病方面起着重要作用。近30年来,人们对益生菌的特性、分类、分布与营养等方面的研究很多,特别是益生菌抑制肠道慢性炎症及维持肠道稳态方面的作用引起了国内外学者的广泛关注。近几年来,随着分子生物学技术的迅速发展,关于益生菌抑制肠道慢性炎症及维持肠道稳态方面的作用机制成为当前研究的热点,并取得了一定的成果。本文目的在于对益生菌抑制肠道慢性炎症及维持肠道稳态的作用进行分析。     

Excitatory effects of synchronized intestinal electrical stimulation on small intestinal motility in dogs

The aim of this study was to investigate effects of synchronized intestinal electrical stimulation (SIES) on small intestinal motility in dogs. Seventeen dogs were equipped with a duodenal cannula for the measurement of small bowel motility using manometry; an additional cannula was equipped in six of the dogs with 1.5 m distal to the first one for the measurement of small intestinal transit. Two pairs of bipolar electrodes were implanted on the small intestinal serosa with an interval of 5 cm; glucagon was used to induce postprandial intestinal hypomotility. Eleven dogs were used for the assessment of the small intestinal contractions in both fasting and fed states. The other six dogs were used for the measurement of small intestinal transit. We found that 1) SIES induced small intestinal contractions during phase I of the migrating motor complex (MMC) (contractile index or CI: 5.2 +/- 0.6 vs. 10.3 +/- 0.7, P = 0.003); 2) in the fed state, SIES significantly improved glucagon-induced small intestinal postprandial hypomotility (CI: 3.4 +/- 0.5 vs. 6.0 +/- 0.3, P = 0.03); 3) SIES significantly accelerated small intestinal transit delayed by glucagon (70.4 +/- 3.1 vs. 44.5 +/- 3.1 min, P < 0.01); 4) there was a negative correlation between the CI and transit time (r = -0.427, P = 0.048); and 5) the excitatory effect of SIES was blocked by atropine. SIES may have a therapeutic potential for treating patients with small intestinal disorders.     

活血化瘀法对肠道菌群结构及 肠屏障功能影响的研究

随着人们对于肠道菌群种类以及作用认识的逐渐深入,我们发现作为人体庞大而又复杂的微生态系统,肠道菌群的结构及和菌群分布有紧密联系的肠屏障功能的改变与人体的健康息息相关。中药作为传统医学的一种治疗方法,其对人体的治疗作用是十分显著的,而活血化瘀法是使用具有消散作用及攻逐体内淤血作用的药物来治疗人类各种疾病的一种方法,这种方法对于肠道菌群以及肠屏障功能也产生了深远的影响。本文围绕肠道菌群结构改变及肠黏膜屏障功能的变化,对近十年关于肠道菌群与活血化瘀方药的相关文献进行综述,探究活血化瘀法(中药及中药复方)对于肠道菌群的影响,为临床治疗提供新思路。     

空气颗粒物与肠道微生物群及肠道炎症相关性研究进展

颗粒物(particulate matter,PM)是空气污染物中的主要成分,可以通过多种途径进入肠道.研究证实颗粒物进入肠道能够增加肠上皮的通透性,降低肠道免疫屏障功能,也可被代谢为有毒产物进一步引起肠道损伤.颗粒物还能够改变肠道微生物群的组成,目前认为微生物群和机体多个系统的功能密切相关.颗粒物引发的肠道炎症反应影...     

肠道菌群影响黏膜屏障结构与功能的研究进展

肠道黏膜屏障具有防止致病性抗原侵入、维护肠道健康的功能。而肠道菌群是肠道黏膜屏障的重要构成部分,肠道菌群失调会导致肠道黏膜屏障的损伤,引起炎性肠病、肠易激综合征及肝、肾等多种疾病的发生发展。因此,本文从肠道黏膜的结构与功能及肠道菌群对其的影响等方面归纳总结肠道菌群对屏障系统的调控作用,从调节肠道微生态平衡、促进黏液分泌、影响紧密连接和肠道上皮通透性、激发肠黏膜免疫、调控肠上皮凋亡、影响肠上皮DNA稳定性及产生特殊代谢产物等方面阐述其作用机制,为临床胃肠道疾病及其并发症的治疗提供新的思路和方法。     

肠道菌群与肠黏膜免疫及相关肠道疾病的研究进展

肠道菌群与肠黏膜免疫之间存在密切的关系,二者相互促进、相互影响,共同维持肠道微生态的平衡,二者失衡可造成肠道器质性及功能性的病变。对肠道菌群、肠黏膜免疫及相关肠道疾病的研究进展作一综述。     

Autophagy in the intestinal epithelium is not involved in the pathogenesis of intestinal tumors

Autophagy has been demonstrated to be associated with the pathogenesis of cancer, but no consensus has been reached about its precise role. Therefore, we investigated whether autophagy in the intestinal epithelium is involved in the pathogenesis of intestinal tumors. To evaluate the relationship between autophagy and intestinal tumors, GFP-LC3-APC(min/+) mice were generated by mating GFP-LC3 transgenic mice with APC(min/+) mice. Autophagy was weakly induced in the intestinal polyp regions of the mice in comparison to their non-polyp regions. Under starved conditions, autophagy was not induced in the polyp regions, whereas it was observed in the non-polyp regions. Then, to examine whether a lack of autophagy in the intestinal epithelium enhances the induction of intestinal tumor, Atg7flox/flox:vil-cre-APC(min/+) mice, in which Atg7 had been conditionally deleted in the intestinal epithelium, were generated by mating Atg7flox/flox:vil-cre mice with APC(min/+) mice. However, there was no significant difference in the number of intestinal polyps between the Atg7flox/flox:vil-cre-APC(min/+) and the corresponding control Atg7flox/flox-APC(min/+) mice. These results indicate that autophagy in the intestinal epithelium is not involved in the pathogenesis of intestinal tumors, and future research should focus on regulating autophagy as a form of cancer therapy.     

Effect of intestinal ischaemia on intestinal VIP levels and VIP interaction with intestinal epithelial cells from rat

1. The number (but not the affinity) of vasoactive intestinal peptide (VIP) receptors in small intestinal epithelial cells decreased following intestinal ischaemia in rats as compared to sham-operated animals. 2. There was a parallel decrease of the efficiency (but not the potency) of the neuropeptide upon cyclic AMP formation at the same level after intestinal ischaemia. 3. The surgical manipulation did not modify the level of VIP immunoreactivity in the gut segment studied. 4. These results suggest that the VIPergic system is not directly involved in the high loss of water and electrolytes that appears following intestinal ischaemia.     

Interaction of vasoactive intestinal peptide with rat small intestinal epithelial cells after intestinal resection

Specific binding of vasoactive intestinal peptide (VIP) and VIP-stimulated c y c l i c AMP accumulation were studied in small intestinal epithelial cells (both of crypt and villous levels) 3, 7 and 14 d after a 60% resection of the small intestine . The affinity, but not the binding capacity, of VIP receptors decreased during the adaptive hyperplastic response. Basal cyclic AMP levels were similar in cells of both control and resected rats. Resection induced a decrease of potency, but not of efficiency, of VIP on the stimulation of cyclic AMP accumulation.     

肠道真菌研究进展

摘要：肠道真菌是肠道微生物的重要组成部分，在肠道正常菌群中所占比例极小，主要包括假丝酵母属（Candida）、隐球酵母属（Cryptococcus）、青霉属（Penicillium）、曲霉属（Aspergillus）、红酵母属（Rhodotorula）等，对维持肠道微生态稳态和机体健康具有重要作用，也与抗生素相关性腹泻（AAD）、乙型肝炎、炎症性肠病（IBD）等疾病的发病机制息息相关。本文主要总结了目前已发现的肠道真菌属及其对人体的影响机制以及肠道真菌相关的研究方法，为肠道真菌在疾病的诊断和治疗方面的进一步研究提供依据与思路。     

Phylogenetic analysis of intestinal bacteria and their adhesive capability in relation to the intestinal mucus of carp

AIMS: The aims of the present study are to characterize the intestinal microbial community displaying a high-adhesive capability in fish, and to evaluate the relationship between mucosal adhesion of intestinal bacteria and fish health and disease. METHODS AND RESULTS: A total of 707 aerobic bacteria isolated from carp intestine that were maintained under either feeding (feeding group) or no-feeding (no-feeding group) conditions and were performed adhesive assay. Isolates were divided into three categories on the basis of adhesive capability: high-, medium-, and low- adhesive capabilities. The average proportions of isolates with high-adhesive capability in the feeding and no-feeding groups were 30% and 32%, respectively. A phylogenetic analysis using a partial 16S rRNA gene demonstrated that most isolates with high-adhesive capability in both groups were classified as belonging to an Aeromonas group, and populations of isolates within high- and low-adhesive categories were markedly different. CONCLUSIONS: Intestinal bacteria with a high-adhesive capability in relation to intestinal mucous always colonize on the surface of intestinal mucosa and grow in the intestinal tract of feeding carp. The adhesive capability of intestinal bacteria is essential for colonization and growth in the intestinal tract of fish. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results indicate that members of the Aeromonas group with adhesive capability always colonize on the surface of intestinal mucosa.     

膳食纤维与肠道健康

由于食物的精加工和生活习惯改变,运动减少,现代人的肠道健康状况下降,肠道疾病发病率不断增加,这已经影响到人们的身体健康和日常生活。肠道疾病的发生多与有毒有害物质在肠道内过久滞留,引起肠道环境改变恶化,进而损伤肠道细胞并引发各类炎症有关。本研究综述了59篇有关于膳食纤维和肠道相互作用的文献。研究表明摄入膳食纤维有助于促进肠道蠕动,保持大便顺畅,防止便秘,清除肠道内的有毒有害物质,保持肠道清洁和促进肠道内的益生菌生长等功效。而且,膳食纤维对肠易激综合征,炎症性肠病和肠癌等常见肠道疾病也具有一定的预防和治疗作用。综上,膳食纤维的摄人有益于保持肠道正常生理功能,修复和改善受损肠道环境,对于维护肠道健康有重要意义。     

术前补充益生菌对肠道手术患者术后肠道菌群 及肠黏膜屏障功能的影响

目的探讨术前补充益生菌对肠道手术患者术后肠道菌群及肠黏膜屏障功能的影响。方法选取肠道手术患者86例,随机分为观察组和对照组各43例。两组患者术前予以常规肠道准备,术后给予等营养支持及抗生素等治疗。观察组患者术前7 d开始加用双歧杆菌三联活菌胶囊温水口服,630 mg/次,2次/d。观察两组患者术后肠道功能恢复及感染并发症情况,并比较术前7 d及术后首次自然排便时两组患者肠道菌群数量及肠黏膜屏障指标变化。结果观察组患者术后肠鸣音恢复时间、肛门排气时间、排便时间均短于对照组(均P0.05),术后感染并发症的发生率低于对照组(P0.05)。术后首次自然排便时两组患者肠道双歧杆菌、乳杆菌数量及B/E值显著低于术前7 d时,大肠埃希菌数量高于术前7 d时(均P0.05),且观察组患者术后双歧杆菌、乳杆菌数量及B/E值均高于对照组,大肠埃希菌数量明显少于对照组(P0.05)。术后首次自然排便时两组患者血清D-乳酸和DAO水平高于术前7 d时(P0.05),且观察组患者术后D-乳酸和DAO水平低于对照组(P0.05)。结论肠道手术患者术前补充益生菌可调节肠道菌群,降低肠黏膜通透性,改善其肠道功能,减少术后感染并发症的发生率。     

肠道菌群在机体免疫调节功能中的作用

肠道菌群被称为是人体的一个重要"器官",具有数量庞大、种类繁多等特点,对人体具有重要的生理与病理意义。肠道菌群对机体免疫功能的影响日益受到广泛关注。本文主要就肠道菌群对肠道形态及功能、肠道黏膜免疫系统以及肠道外免疫系统三个方面的影响进行综述。     

Permanent jejunal fistula: promising method for obtaining small intestinal chyme without disturbing intestinal function

Accurate information on changes in small intestinal microflora in dogs is rather limited because of difficulties in obtaining samples of small intestinal chyme. In the study reported here, intussuscepted nipple valves were surgically placed into the jejunum of seven laboratory beagles to obtain intestinal juice samples. The influence of the fistula on intestinal motility was determined by use of barium-impregnated polyethylene spheres (BIPS) and on microflora by use of bacterial culturing. The BIPS were fed two weeks before surgery and again five weeks after surgery. Bacterial samples were collected before (fecal samples), during (small intestinal samples) and 11 weeks after surgery. There were no surgical complications, and the animals tolerated the fistula well. Mean orocolic transit percentage was 93% before and 83% after surgery, and notable changes in gastrointestinal motility were not seen, except in one dog. The surgery did not markedly alter the bacterial flora in feces. Microflora did change in small intestinal samples; however, methodologic factors may explain most of these differences. In conclusion, the nipple valve is a promising method that creates easy and safe long-term access to the jejunum and appears not to have an influence on intestinal function.     

肠道菌群变化对实验小鼠肠黏膜免疫的影响

目的探讨肠道菌群变化对肠黏膜相关淋巴组织的影响。方法通过变性梯度凝胶电泳（Denatu-ring gradient gel electrophoresis,DGGE）法研究了三种不同级别实验小鼠即清洁级小鼠、SPF小鼠和普通小鼠肠道菌群的组成,并用免疫组织化学（immunohistochemistry,IHC）方法研究了此三种不同级别的实验小鼠肠黏膜相关淋巴组织sIgA阳性细胞分布情况。结果普通小鼠肠道细菌种类最多,其sIgA阳性细胞分布最多,肠道不同部位之间sIgA分布情况差异有显著性（P〈0.05）,小肠和大肠之间的阳性细胞分布差异极显著（P〈0.01）;其次是清洁级小鼠,其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异有显著性（P〈0.05）;SPF小鼠肠道细菌种类最少,故其sIgA阳性细胞分布最少,且其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异无显著性（P〉0.05）。结论随着动物微生物控制级别的增高,肠道微生物多样性递减;sIgA阳性细胞与肠道细菌种类正相关。     

Relationship between intestinal microecology and the translocation of intestinal bacteria

It is now well known that endogenous bacteria can translocate from the intestinal tract and cause many of the complicating infections seen in severely ill, hospitalized patients. Of the hundreds of bacterial species in the intestinal tract, relatively few aerobic/facultative species appear to translocate with any frequency. Van der Waaij and colleagues (1971, 1972a, 1972b) originally proposed that, by a process termed colonization resistance, strictly anaerobic bacteria prevented the intestinal overgrowth and subsequent translocation of these potentially pathogenic aerobic/facultative bacteria. Selective antimicrobial decontamination, designed to maintain colonization resistance, has been effective in reducing the incidence of infectious morbidity in high risk patients. However, the mechanisms controlling bacterial translocation remain unclear, but appear to depend on host factors, as well as on factors inherent in the microbe itself. There is both clinical and experimental evidence supporting the concept that strictly anaerobic bacteria do not readily translocate. Bacteria that are able to survive within macrophages (e.g., Salmonella species and Listeria monocytogenes) translocate easier than others, and there is recent experimental evidence that normal intestinal bacteria may translocate to the draining mesenteric lymph node within host phagocytes. There is also evidence that anaerobic bacteria translocate along with facultative species in situations associated with intestinal epithelial damage, i.e., burn trauma, oral ricinoleic acid, and acute mesenteric ischemia. In contrast, recent experimental evidence demonstrates that facultative bacteria can translocate across a histologically intact intestinal epithelium, and that the ileal absorptive cell may be at least one portal of entry prior to transport into deeper tissues. It is anticipated that further clarification of the routes and mechanisms involved in bacterial translocation will provide new insights into the treatment and prevention of a significant proportion of the infectious morbidity seen in severely ill, hospitalized patients. Antoni van Leeuwenhoek Lecture presented at the Annual Meeting of the Netherlands Society of Microbiology, Utrecht, 23 November, 1989.