MicroRNA-21 is upregulated during intestinal barrier dysfunction induced by ischemia reperfusion

This study aimed to investigate the expression of miRNA-21 during intestinal barrier dysfunction induced by intestinal ischemia reperfusion. Forty SPF SD rats were divided into 5 groups randomly. Intestinal ischemia-reperfusion injury (IRI) was induced by mesenteric artery occlusion for 1 h and reperfusion for 1 h, and the rats were sacrificed at 1, 3, 6 and 12 h after reperfusion. Fresh intestine tissues were immediately isolated for the measurement of transepithelial electrical resistance (TER). The levels of cytokines, ICAM-1, DAO, iFABP and MPO in serum were determined by ELISA. Intestinal tight junction proteins occludin and claudin-1 were detected by immunofluorescence analysis and Western blot analysis. miR-21 expression in intestinal tissues was measured by RT-PCR. Compared with sham group, the levels of pro-inflammatory cytokines TNF-α and IL-6 and ICAM-1, DAO, iFABP and MPO increased while IL-10 level decreased in intestinal ischemia-reperfusion group. In addition, the levels of intestinal tight junction proteins occludin and claudin-1 decreased while miR-21 level increased in intestinal ischemia-reperfusion group, compared with sham group. In conclusion, miR-21 expression is upregulated during intestinal barrier dysfunction induced by IRI. miR-21 may play an important role in the regulation of intestinal barrier function.     

非侵入性方法检测肠黏膜屏障功能的研究进展

异常的肠道通透性在人类多种疾病中起着非常重要的作用,包括糖尿病、炎症性肠病、乳糜泻、多发性硬化、食物变态反应过敏症、肠易激综合征等.近年大量的研究发现:一些自身免疫性疾病伴有肠道通透性增加,这种现象发生在疾病之前,被认为与疾病的发病机制相关.研究肠黏膜屏障的功能与结构,可以提高我们对疾病的病因及病理生理认识,并且对于早期检测疾病以及对疾病进行二级预防有重要意义.目前有多种试验方法评估肠黏膜上皮细胞受损、紧密连接功能以及肠黏膜屏障的完整性.本篇综述主要探讨目前评估肠黏膜屏障功能的检测方法.     

益生元对急性胰腺炎大鼠肠屏障功能的影响

目的 研究肠道补充益生元对急性胰腺炎肠上皮细胞紧密连接和屏障功能的影响.方法 Wistar大鼠腹腔注射左精氨酸建立AP模型,按随机数字法分组法分成对照组、AP组、益生元组.益生元组于造模前7 d开始给予益生元4 g·kg-1·d-1.建模后12 h处死大鼠,心脏取血检测血浆二胺氧化酶(DAO)活性,观察空肠病理变化、采用免疫组化方法检测紧密结合蛋白Occludin的含量.结果 AP组的血浆DAO活性为(7.29±0.68)U/L,显著高于对照组的(2.01±0.34)U/L(P＜0.01)和益生元组的(3.44±0.59)U/L(P＜0.05).AP组肠上皮occludin蛋白表达的灰度值为95.1±9.2,明显高于对照组的44.7±8.2和益生元组的59.7±7.8(P＜0.01).益生元组occludin表达也显著高于对照组(P＜0.05).结论 AP大鼠补充益生菌可增加肠上皮occludin蛋白表达,维持肠上皮紧密连接,维持正常的肠道通透性,从而达到保护肠黏膜屏障的效果.     

Intestinal barrier dysfunction in cirrhosis: Current concepts in pathophysiology and clinical implications

The intestinal lumen is a host place for a wide range of microbiota and sets a unique interplay between local immune system, inflammatory cells and intestinal epithelium, forming a physical barrier against microbial invaders and toxins. Bacterial translocation is the migration of viable or nonviable microorganisms or their pathogen-associated molecular patterns, such as lipopolysaccharide, from the gut lumen to the mesenteric lymph nodes, systemic circulation and other normally sterile extraintestinal sites. A series of studies have shown that translocation of bacteria and their products across the intestinal barrier is a commonplace in patients with liver disease. The deterioration of intestinal barrier integrity and the consulting increased intestinal permeability in cirrhotic patients play a pivotal pathophysiological role in the development of severe complications as high rate of infections, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatorenal syndrome, variceal bleeding, progression of liver injury and hepatocellular carcinoma. Nevertheless, the exact cellular and molecular mechanisms implicated in the phenomenon of microbial translocation in liver cirrhosis have not been fully elucidated yet.     

肠屏障和肝屏障损伤及保护在减体积肝移植术后小肝综合征中的研究进展

肠屏障可以抵抗病原体的侵袭,阻止有害物质进入血液循环,从而保持机体内环境的稳定.肝屏障对于维护肝脏正常功能有重要意义,其可阻止内毒素、病毒等进入肝脏损伤肝细胞.肠屏障和肝屏障是减体积肝移植术后最易受到损伤的2个结构,其损伤的原因与术后"小肝综合征"的发生有关."小肝综合征"的发病机制与肝移植术后门静脉高压、门静脉过度灌注等有关.如何有效地控制"小肝综合征"的发生,保护术后的肠屏障和肝屏障,是维持肠道和肝脏功能的关键点.本文主要阐述肠屏障和肝屏障的概念,分析其功能和结构破坏的原因以及相应的保护措施.     

Protective effects of Lactobacillus plantarum against epithelial barrier dysfunction of human colon cell line NCM460

AIM: To investigate the effects of Lactobacillus plantarum (L. plantarum ) in the intestinal permeability and expression of tight junction (TJ) using the normal human colon cell line NCM460. METHODS: Paracellular permeability of NCM460 monolayers was determined by transepithelial electrical resistance and dextran permeability. Expression of TJ proteins in NCM460 cell monolayers was detected by Western blotting and quantitative real-time polymerase chain reaction.RESULTS: L. plantarum played an important role in increasing transepithelial electrical resistance and decreasing the permeability to macromolecules of NCM460 monolayers against the disruption caused by enteropathogenic Escherichia coli (E. coli ) or enteroinvasive E. coli . L. plantarum also prevented the decrease in the expression of TJ proteins and F-actin in NCM460 cells.CONCLUSION: L. plantarum can protect against dysfunction of NCM460 intestinal epithelial barrier caused by enteropathogenic E. coli or enteroinvasive E. coli , and thus can be a potential candidate of therapeutic agents for the treatment of intestinal diseases.     

Cellular and molecular basis of intestinal barrier dysfunction in the irritable bowel syndrome

The etiopathogenesis of the irritable bowel syndrome (IBS), one of the most prevalent gastrointestinal disorders, is not well known. The most accepted hypothesis is that IBS is the result of the disturbance of the 'brain-gut axis.' Although the pathophysiological mechanisms of intestinal dysfunction are complex and not completely understood, stress, infections, gut flora, and altered immune response are thought to play a role in IBS development. The intestinal barrier, composed of a single-cell layer, forms a physical barrier that separates the intestinal lumen from the internal milieu. The loss of integrity of this barrier is related with mucosal immune activation and intestinal dysfunction in IBS. The number of mast cells and T lymphocytes is increased in the intestinal mucosa of certain IBS patients, and the mediators released by these cells could compromise the epithelial barrier function and alter nerve signaling within the enteric nervous system. The association of clinical symptoms to structural and functional abnormalities of the mucosal barrier in IBS patients highlights the importance of understanding the physiological role of the gut barrier in the pathogenesis of this disorder. This review summarizes the clinical and experimental evidences indicating the cellular and molecular mechanisms of IBS symptomatology, and its relevance for future translational research.     

急性胆道梗阻肠黏膜屏障破坏与氯离子通道-2的关系

目的:探讨急性胆道梗阻肠黏膜屏障破坏与肠上皮细胞氯离子通道-2(chloride channel-2,CLC-2)的关系.方法:建立急性胆道梗阻(阻塞性黄疸)大鼠动物模型,术后7d连续注射Lubiprostone(Lu组)、类高血糖素多肽-2(GLP-2组)、两者共同使用(Lu+GLP组),以假手术组(Sham组)和阻...     

肠屏障功能障碍的研究现状与展望

肠屏障功能障碍正日益受到关注,多种疾病均可引起肠屏障功能障碍,促使细菌移位,加重原发病,形成恶性循环。此文就肠屏障功能障碍的发病机制、检测方法和治疗措施进展作一综述。     

肠黏膜屏障损伤与保护分子机制研究进展

介绍肠黏膜屏障损伤因素的分子机制,如内毒素及氧自由基、炎症介质和细胞因子如白细胞介素（interleukin）、肿瘤坏死因子-α（TNF-α）、核转录因子kappa B、TOLL样受体（TLRs）和NOD受体通路、高迁移率族蛋白B1、烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶（NOX）等。对肠黏膜屏障的保护分子机制如肠上皮紧密连接蛋白、白介素家族、其它保护性调控因子等作出介绍。     

乌司他丁对乙醇诱导的肠黏膜屏障损伤的保护作用

目的探讨乌司他丁对乙醇诱导的肠黏膜屏障损伤的保护作用。方法培养Caco-2细胞至形成肠上皮细胞屏障模型,分为空白对照组、乙醇组(终体积浓度10%)和不同浓度乌司他丁治疗组(750 U/mL、1 500 U/mL、3 000 U/mL)。测定单层上皮的跨上皮细胞电阻(TEER)及荧光素钠透过率,免疫荧光法及蛋白质免疫印迹法(Western blot)检测紧密连接蛋白ZO-1在细胞单层的定位及表达量,透射电镜观察细胞紧密连接的超微结构。结果与对照组对比,乙醇组单层细胞的TEER降低(P0.001);荧光素钠透过率升高(P0.001);免疫荧光检测显示ZO-1蛋白表达断续不完整,荧光强度弱;Western blot检测显示ZO-1蛋白表达水平降低(P0.001);透射电镜结果示细胞刷状缘受损,排列紊乱,细胞间连接模糊。乌司他丁治疗组的上述指标均改善(P均0.05),其中3 000 U/mL乌司他丁组的改善最明显(P均0.05)。结论乌司他丁对乙醇诱导的肠单层上皮细胞屏障损伤具有保护作用。     

肥大细胞在应激性肠屏障损伤中的作用

1肥大细胞的生物学特性 1．1来源及分型肥大细胞是一种重要炎症效应细胞，来源于骨髓多能造血干细胞的肥大细胞前体，经过血液循环进入组织内。正常情况下，肥大细胞广泛分布于全身结缔组织、呼吸道和消化道黏膜、血管和淋巴管周围，肥大细胞的这种分布可使其产物被血管内皮细胞、呼吸道、胃肠道平滑肌细胞所利用。动物肥大细胞分为黏膜肥大细胞MMC和结缔组织肥大细胞CT—MC。人类肥大细胞分为含类胰蛋白酶的MCT型及含类胰蛋白酶和胃促胰酶的MCTC型。MCT与MMC相似，主要位于肠黏膜固有层和肺脏，而MCTC与CTMC相似，主要位于皮肤和肠黏膜下层。肥大细胞在循环中以未分化的定向前体形式存在，易于聚集在炎症部位，并增殖为成熟肥大细胞。     

肠道屏障功能障碍的干预研究进展

目前已知,肠道屏障功能在多种严重疾病如烧伤、重症胰腺炎、肿瘤、严重肝病等的发生、发展过程中发挥重要的“枢纽”作用.随着人们对肠黏膜功能障碍在各种严重疾病发生、发展中所起的重要病理生理作用的不断认识,针对患者肠黏膜屏障功能变化进行干预的基础和临床研究日益受到广大学者的关注.本文就近年来国内外对这一领域的研究进展作一综述.     

Combined probiotic bacteria promotes intestinal epithelial barrier function in interleukin-10-gene-deficient mice

AIM:To investigate the protective effects of combinations of probiotic(Bifico)on interleukin(IL)-10-genedeficient(IL-10 KO)mice and Caco-2 cell monolayers.METHODS:IL-10 KO mice were used to assess the benefits of Bifico in vivo.IL-10 KO and control mice received approximately 1.5×108 cfu/d of Bifico for 4 wk.Colons were then removed and analyzed for epithelial barrier function by Ussing Chamber,while an ELISA was used to evaluate proinflammatory cytokines.The colon epithelial cell line,Caco-2,was used to test the benefit of Bifico in vitro.Enteroinvasive Escherichia coli(EIEC)and the probiotic mixture Bifico,or single probiotic strains,were applied to cultured Caco-2 monolayers.Barrier function was determined by measuring transepithelial electrical resistance and tight junction protein expression.RESULTS:Treatment of IL-10 KO mice with Bifico partially restored body weight,colon length,and epithelial barrier integrity to wild-type levels.In addition,IL-10 KO mice receiving Bifico treatment had reduced mucosal secretion of tumor necrosis factor-αand interferon-γ,and attenuated colonic disease.Moreover,treatment of Caco-2 monolayers with Bifico or singlestrain probiotics in vitro inhibited EIEC invasion and reduced the secretion of proinflammatory cytokines.CONCLUSION:Bifico reduced colon inflammation in IL-10 KO mice,and promoted and improved epithelialbarrier function,enhanced resistance to EIEC invasion,and decreased proinflammatory cytokine secretion.     

Acute pancreatitis is characterized by generalized intestinal barrier dysfunction in early stage

Background and aimsThe role of intestinal-barrier in acute pancreatitis(AP) is poorly understood. We aimed to assess structural and functional changes in the intestinal-barrier in patients with early AP (time from onset<2 weeks) and the effect of enteral nutrition on them.MethodsIn this prospective observational study, patients with early AP not on enteral nutrition were compared with controls for baseline intestinal-permeability(lactulose: mannitol ratio(L:M)), endotoxinemia(serum IgM/IgG anti-endotoxin antibodies), bacterial-translocation(serum bacterial 16S rRNA) and duodenal epithelial tight-junction structure by immunohistochemistry(IHC) for tight-junction proteins(claudin-2,-3,-4, zonula occludens-1(ZO1), junctional adhesion molecule(JAM) and occludin) and electron microscopy. These parameters were reassessed after 2 weeks enteral feeding in a AP patients subset.Results96 patients with AP(age: 38.0 ± 14.5 years; etiology: biliary[46.8%]/alcohol[39.6%]; severe:53.2%, mortality:11.4%) and 40 matched controls were recruited. Patients with AP had higher baseline intestinal permeability(median L:M 0.176(IQR 0.073–0.376) vs 0.049(0.024–0.075) in controls; p < 0.001) and more frequent bacteraemia(positive bacterial 16S rRNA in 24/48 AP vs 0/21 controls; p < 0.001) with trend towards higher serum endotoxinemia(median IgG anti-endotoxin 78(51.2–171.6) GMU/ml vs 51.2(26.16–79.2) in controls; p = 0.061). Claudin-2, claudin-3, ZO1 were downregulated in both duodenal crypts and villi while claudin-4 and JAM were downregulated in duodenal villi and crypts respectively. 22 AP patients reassessed after initiation of enteral nutrition showed trend towards improving intestinal permeability, serum endotoxinemia and bacteraemia, with significant improvement in claudin-2,-3 in duodenal villi.ConclusionPatients with AP have significant disturbances in intestinal barrier structure and function in first 2 weeks from onset that persist despite institution of enteral nutrition.     

肠黏膜细胞的紧密连接与肠壁通透性的研究进展

肠黏膜细胞的紧密连接是构成肠黏膜屏障的重要结构基础,在调节肠黏膜通透性中发挥着重要的作用.其结构的破坏,可导致肠壁通透性增高,引起细菌移位、全身炎症反应及多器官功能受损.本文就肠黏膜紧密连接的结构和功能、与通透性的影响因素及改善措施进行了综述.     

Electroacupuncture improves gut barrier dysfunction in prolonged hemorrhagic shock rats through vagus anti-inflammatory mechanism

AIM:To investigate whether electroacupuncture(EA)at Zusanli(ST36)prevents intestinal barrier and remote organ dysfunction following prolonged hemorrhagic shock through a vagus anti-inflammatory mechanism.METHODS:Sprague-Dawley rats were subjected to about 45%of total blood volume loss followed by delayed fluid replacement(DFR)with Ringer lactate 3h after hemorrhage.In a first study,rats were randomly divided into six groups:(1)EAN:EA at non-channel acupoints followed by DFR;(2)EA:EA at ST36 after hemorrhage followed by DFR;(3)VGX/EA:vagotomy(VGX)before EA at ST36 and DFR;(4)VGX/EAN:VGX before EAN and DFR;(5)α-bungarotoxin(α-BGT)/EA:intraperitoneal injection ofα-BGT before hemorrhage,followed by EA at ST36 and DFR;and(6)α-BGT/EAN group:α-BGT injection before hemorrhage followed by EAN and DFR.Survival and mean arterial pressure(MAP)were monitored over the next 12 h.In a second study,with the same grouping and treatment,cytokine levels in plasma and intestine,organ parameters,gut injury score,gut permeability to 4 kDa FITC-dextran,and expression and distribution of tight junction protein ZO-1 were evaluated.RESULTS:MAP was significantly lowered after blood loss;EA at ST36 improved the blood pressure at corresponding time points 3 and 12 h after hemorrhage.EA at ST36 reduced tumor necrosis factor-αand interleukin(IL)-6 levels in both plasma and intestine homogenates after blood loss and DFR,while vagotomy or intraperitoneal injection ofα-BGT before EA at ST36reversed its anti-inflammatory effects,and EA at ST36did not influence IL-10 levels in plasma and intestine.EA at ST36 alleviated the injury of intestinal villus,the gut injury score being significantly lower than that of EAN group(1.85±0.33 vs 3.78±0.59,P<0.05).EA at ST36 decreased intestinal permeability to FITCdextran compared with EAN group(856.95 ng/mL±90.65 ng/mL vs 2305.62 ng/mL±278.32 ng/mL,P<0.05).EA at ST36 significantly preserved ZO-1 protein expression and localization at 12 h after hemorrhage.However,EA at non-channel acupoints had     

重症急性胰腺炎肠屏障功能障碍研究

重症急性胰腺炎患者常伴有肠屏障功能障碍,正常肠道屏障由机械屏障、化学屏障、免疫屏障与微生物屏障4部分构成.肠屏障功能障碍通常指上述4种屏障功能出现不同程度的破坏,本文就重症急性胰腺炎肠道屏障功能障碍时上述4种屏障的病理生理改变作一概述.