幽门螺杆菌黏附素及其致病作用的研究进展

幽门螺杆菌(Helicobacter pylori,H. pylori)黏附素是由H. pylori表达并参与H. pylori对胃黏膜的黏附、定植的一种外膜蛋白。这些黏附素不仅参与对胃黏膜的黏附、定植,还与H. pylori的持续感染和疾病的严重程度密切相关。该文结合近几年国内外文献,对H. pylori黏附素、黏附受体及其致病作用的研究进展作一概述。     

幽门螺杆菌与胃上皮细胞间连接的相关研究进展

幽门螺杆菌(Helicobacter pylori,H.pylori)是高感染率的慢性致病菌,导致相关疾病的分子机制非常复杂。近年的研究发现,H.pylori在破坏胃上皮屏障的结构和功能中起重要作用,是H.pylori相关炎症和肿瘤转化的重要标志。本文主要阐述H.pylori致病因子包括空泡细胞毒素(VacA)、细胞毒素相关蛋白(CagA)、脲素酶(urease)和细胞蛋白酶等破坏胃上皮细胞间连接的分子机制。     

幽门螺杆菌黏附素HpaA蛋白在大肠杆菌中表达及其免疫保护作用

目的表达和纯化幽门螺杆菌(Helicobacter pylori,H.pylori)黏附素HpaA蛋白,研究其免疫活性和对小鼠的免疫保护作用。方法诱导TB1(pMAL-c2X-hpaA)表达H.pylori黏附素HpaA蛋白,Amyloss树脂预装柱进行分离、纯化,Western blot鉴定其免疫学活性;纯化蛋白免疫小鼠后,H.pylori国际标准菌株NCTC11637攻击感染,观察H.pylori定植情况及免疫保护效果。结果获得了高纯度且免疫活性良好的目的蛋白;HpaA蛋白免疫小鼠的保护率为53.33%(8/15),与对照组统计学差异显著(P=0.002)。结论纯化HpaA蛋白对小鼠有免疫保护作用,可作为H.pylori基因工程疫苗的候选组分。     

胃粘膜相关淋巴样组织淋巴瘤抗H.Pylori治疗的有效预测因子

胃粘膜相关淋巴样组织(MALT)型结外边缘区B细胞淋巴瘤发病机制主要与幽门螺杆菌(H.pylori)感染有关,目前认为根治H.pylori治疗已成为胃粘膜相关淋巴样组织淋巴瘤的一线治疗。然而,抗H.pylori治疗不能使胃MALT淋巴瘤100%完全缓解,即使完全缓解后仍有复发的可能。随着研究的深入,哪些患者更能从抗H.pylori治疗中受益,抗H.pylori治疗后随访是目前研究的热点。此文对胃MALT淋巴瘤与H.pylori的关系,抗H.pylori治疗的有效预测、随访作一综述。     

幽门螺杆菌感染与糖尿病

糖尿病患者幽门螺杆菌(Helicobacter pylori,H.pylori)感染率明显增加,H.pylori感染作为一个独立因素可促使胰岛素抵抗.糖尿病患者中的H.pylori根除率较正常人为低,合并H.pylori感染的糖尿病患者血糖波动范围增大,血糖不易被控制,治疗效果不佳,而根除H.pylori后有助于改善糖尿病的进展.H.pylori感染与糖尿病并发症(如糖尿病肾病、动脉粥样硬化、胃轻瘫等)的发生也有一定关系.H.pylori感染影响糖尿病的机制可能与系统性炎症反应、血管内皮损伤和激素水平改变(如瘦素和胃饥饿素)等因素有关.     

幽门螺杆菌及其根除治疗与胃癌前病变

幽门螺杆菌 (H .pylori)感染与胃癌前病变的发生及演变过程密切相关 ,而其根除治疗在胃癌前病变干预和治疗中的作用倍受争议。该文综述了胃癌前病变中H .pylori的感染状况 ;H .pylori致萎缩、肠化的机制 ;H .pylori对胃癌前病变细胞增殖与凋亡的影响。进一步总结了根除治疗所取得的成果 ,展望了今后研究发展的方向和前景。     

吲哚胺2,3-双加氧酶1对幽门螺旋杆菌免疫调节的研究进展

幽门螺旋杆菌(Helicobacter pylori,H.pylori)是一种广泛黏附定植于胃黏膜的革兰阴性杆菌,流行病学研究显示,H.pylori感染是慢性胃炎的主要病因,长期停留于胃内可能导致慢性浅表性胃炎、慢性萎缩性胃炎、肠化生、异型增生和最终胃癌的发生;吲哚胺2,3-双加氧酶1(indoleamine 2,3-dioxygenase1,IDO1)是一种免疫调节酶,可在炎症过程中激活,诱导免疫耐受而有助于细菌长期生存;本文对胃黏膜中IDO1表达对H.pylori及H.pylori感染胃黏膜疾病发展的免疫调节作一概述。     

胃黏膜病变中HSP60的表达与幽门螺杆菌感染的相关性研究

自 198 2年Warren和Marshall从人胃黏膜成功分离并培养出幽门螺杆菌 (H .pylori)以来 ,其作为亲噬胃黏膜的致病菌已得到共识 ,H .pylori感染在胃、十二指肠疾病的发生中有重要的病因学意义。目前已知所有的H .pylori菌株都产生HSP(热休克蛋白 ) ,包括HSPA和HSPB。HSPB是人HSP6 0的同源物 ,位于细菌表面具有高度的免疫原性 ,抗HSP免疫反应可能在H .pylori感染引起的病理改变过程中有一定作用[1] 。本实验研究HSP6 0在不同病变胃黏膜中的表达 ,并检测了胃黏膜中的H .pylori感染情况 ,以探讨HSP6 0与H .pylori感染之间的关系。1…     

幽门螺杆菌感染与心血管疾病的研究进展

幽门螺杆菌(H. pylori)感染是慢性胃炎、消化性溃疡和胃癌等消化道疾病明确的重要致病因素, 并与多种胃外疾病有关。H. pylori感染与心血管疾病的关系是近年来研究的热点, 也是争论的焦点。许多临床研究发现两者密切相关, 认为H. pylori感染是心血管疾病的致病因素, 但亦有学者认为两者关联性较弱。其原因可能与不同H. pylori菌株类型的致病性差异, 及宿主因素和环境因素等有关。本文回顾了近年来H. pylori与心血管疾病相关的研究, 归纳和分析H. pylori感染在动脉粥样硬化形成中的作用及机制。     

幽门螺杆菌感染对胃上皮细胞增殖影响的实验研究

目的在幽门螺杆菌(H.pylori)长期感染蒙古沙土鼠腺胃模型基础上,探讨H.pylori感染诱致胃癌发生的可能机制.方法采用H.pylori国际标准菌株NCTC11637灌喂蒙古沙土鼠,建立H.pylori长期感染动物模型;用免疫组化及原位杂交方法检测H.pylori感染致胃上皮细胞增殖的改变.结果成功建立了H.pylori长期感染蒙古沙土鼠腺胃模型,其胃粘膜的组织学变化显示,H.pylori感染可致正常胃粘膜→慢性胃炎→萎缩→肠化生→异型增生的发展过程.H.pylori感染对胃上皮细胞增殖的影响:H.pylori感染能引起胃窦上皮细胞增殖增加(P<0.05);随着H.pylori感染时间的增加,EGF mRNA及EGFR mRNA的阳性信号表达呈逐渐增加的趋势(P<0.05) H.pylori定植致胃窦上皮细胞增殖的异常,对正常胃窦粘膜向不典型增生进展的过程起重要作用:EGF及EGFR在mRNA水平的异常表达可能是H.pylori定植致胃窦上皮细胞增殖异常的重要原因。     

Helicobacter pylori enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in human gastric epithelial cells

AIM: To investigate the relations between tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Helicobacter pylori (H pylori) infection in apoptosis of gastric epithelial cells and to assess the expression of TRAIL on the surface of infiltrating T-cells in H pylori-infected gastric mucosa. METHODS: Human gastric epithelial cell lines and primary gastric epithelial cells were co-cultured with H pylori in vitro, then recombinant TRAIL proteins were added to the culture. Apoptosis of gastric epithelial cells was determined by a specific ELISA for cell death. Infiltrating lymphocytes were isolated from H pylori-infected gastric mucosa, and expression of TRAIL in T cells was analyzed by flow cytometry. RESULTS: The apoptosis of gastric epithelial cell lines and primary human gastric epithelial cells was mildly increased by interaction with either TRAIL or H pylori alone. Interestingly, the apoptotic indices were markedly elevated when gastric epithelial cells were incubated with both TRAIL and H pylori (Control vs TRAIL and H pylori: 0.51+/-0.06 vs 2.29+/-0.27, P = 0.018). A soluble TRAIL receptor (DR4-Fc) could specifically block the TRAIL-mediated apoptosis. Further studies demonstrated that infiltrating T-cells in gastric mucosa expressed TRAIL on their surfaces, and the induction of TRAIL sensitivity by H pylori was dependent upon direct cell contact of viable bacteria, but not CagA and VacA of H pylori. CONCLUSION: H pylori can sensitize human gastric epithelial cells and enhance susceptibility to TRAIL-mediated apoptosis. Modulation of host cell sensitivity to apoptosis by bacterial interaction adds a new dimension to the immunopathogenesis of H pylori infection.     

幽门螺杆菌感染时Fas/Fas Ligand介导的T细胞致胃上皮细胞损伤

目的：评价幽门螺杆菌（Hp)感染时胃细胞Fas/Fas Lingand的表达,功能及其对胃上皮细胞的损伤作用,以了解Hp的免疫致病机制,方法：免疫组化方法检测Hp阳性及阴性胃黏膜FasLigand的表达情况,RT－PCR检测胃T细胞FasLigand mRNA的表达,生物检测技术（JAM）评价胃T细胞通过Fas/Fas Ligand作用杀伤靶细胞的活性,并对Fas/Fas Ligand介导的胃T细胞及培养上清致胃型上皮凋亡进行了检测,结果：Hp感染胃组织中单核细胞Fas Ligand阳性而Hp阴性者无表达,Hp阳性胃黏膜T细胞系表达Fas Ligand mRNA,而Hp阴性者则不表达或弱表达,胃T细胞的Fas Ligand具有生物学活性,能杀伤Fas阳笥的Jurkat细胞并特异杀伤胃上皮细胞系,结论：通过激活胃浸润T细胞的Fas Ligand表达而损伤胃型上皮是Hp免疫致病的机制之一,其在Hp感染时黏膜免疫选择中的作用尚需进一步探讨。     

Detection of H.pylori DNA in gastric epithelial cells by in situ hybridization

AIM: To investigate the presence of H.pylori DNA within gastric epithelial cells in patients with H.pylori infection and its possible carcinogenic mechanism. METHODS: Total 112 patients, with pathologically confirmed chronic superficial gastritis, chronic atrophic gastritis, intestinal metaplasia, atypical hyperplasia or gastric cancer were studied. Among them, 28 were H.pylori negative and 84 H.pylori positive. H.pylori DNA in gastric epithelial cells was detected by GenPoint catalyzed signal amplification system for in situ hybridization. RESULTS: In the H.pylori positive group, zero out of 24 chronic superficial gastritis (0.0%), four out of 25 precancerous changes (16.0%) and thirteen out of 35 gastric cancers (37.1%) showed H.pylori DNA in the nucleus of gastric epithelial cells, the positive rates of H.pylori DNA in the nucleus of gastric epithelial cells were progressively increased in chronic superficial gastritis, precancerous changes and gastric cancer groups (chi(2)=12.56, P=0.002); One out of 24 chronic superficial gastritis (4.2%), eleven out of 25 precancerous changes (44.0%) and thirteen out of 35 gastric cancers (37.1%) showed H.pylori DNA in the cytoplasm of gastric epithelial cells (chi(2)=10.86, P=0.004). In the H.pylori negative group, only one patient with gastric cancer was found H.pylori DNA in the nucleus of gastric epithelial cells; Only two patients, one patient with precancerous changes and another with gastric cancer, showed H.pylori DNA in the cytoplasm of gastric epithelial cells. Furthermore, H.pylori DNA must have been in the cytoplasm as long as it existed in the nucleus of gastric epithelial cells. CONCLUSION: H.pylori DNA exists both in the nucleus and the cytoplasm of gastric epithelial cells in patients with H.pylori infections. The pathological progression from chronic superficial gastritis, precancerous changes to gastric cancer is associated with higher positive rates of H.pylori DNA presence in the nucleus of gastric epithelial cells.     

Gastric mucosal recognition of Helicobacter pylori is independent of Toll-like receptor 4

Little is known about the interactions between Helicobacter pylori, which specializes in colonizing the mucin layer that covers the gastric mucosa, and primary gastric epithelial cells. The expression pattern of Toll-like receptors (TLRs) in primary gastric epithelial cells and cell lines was compared. Primary cells did not express TLR4, whereas all cell lines expressed a nonsignaling form of TLR4. Because other cells within the mucosa expressed TLR4, it was next investigated whether H. pylori can be recognized by TLR4--they cannot. Moreover, H. pylori infection of primary cells induced a regulated production of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha, whereas infection of cell lines only resulted in IL-8 production. The cytokine production in all cell types was strictly cag dependent. These findings indicate that, although the epithelium is important in directing the immune response against H. pylori infections, the response is independent of TLR4.     

Claudin在幽门螺杆菌和AGS细胞相互作用不同时间点表达分析

目的研究Claudin家族成员在Helicobacterpylori（H．pylori）和AGS相互作用的不同时间点表达谱变化。方法TRIzol方法提取H．pylori26695攻击AGS细胞0、0．5、2、4、6h时间点的细胞总RNA样品，对样品mRNA进行线性扩增后，应用IlluminaHuman-6芯片检测基因表达量，以DetectionScore≥0．99；IDiffScoreI≥13；方差分析（ANOVA）P≤0．05作为筛选差异基因的标准；比较Claudin家族成员的表达量．结果Claudin家族有4个成员存在差异表达，其中在早期Claudin15下调，4h后无差异，Claudin2、23早期上调后于4h和6h分别恢复至无差异水平，而Claudin6在0．5h后持续上调。结论Claudin蛋白家族2、6、15、23成员参与H．pylori感染过程，并且呈现时序性变化，为H．pylori感染能引发胃癌机制研究提供线索。     

Gastric epithelial cell CXC chemokine secretion following Helicobacter pylori infection in vitro

BACKGROUND AND AIMS: Helicobacter pylori infection of the stomach is commonly associated with infiltration of neutrophils. Gastric epithelial cells are recognized as central mediators of tissue responses to this organism. The aim of the present study was to ascertain patterns of production of three neutrophil chemoattractant chemokines following infection of gastric epithelial cells with H. pylori in vitro. METHODS: Two gastric cancer-derived epithelial cell lines were infected with H. pylori organisms of previously defined cagE and cagA status for periods of up to 24 h. The production of three chemokines (interleukin [IL]-8, epithelial neutrophil activating protein [ENA]-78 and growth-related oncogene [GRO]-alpha) over this time was measured in culture supernatants using immunoassays. RESULTS: Both IL-8 and GRO-alpha were produced by both AGS and KATO-III cells in response to H. pylori infection, and in a cag PAI-dependent manner. ENA-78, however, was not increased following H. pylori infection. CONCLUSIONS: GRO-alpha is expressed by epithelial cells following H. pylori infection along with IL-8. Both may contribute to neutrophilic infiltration present in gastric mucosa associated with H. pylori infection. In contrast, H. pylori infection does not lead to an increased synthesis of ENA-78, suggesting that this may not be as important in vivo.     

cag致病岛的差异及不同激酶抑制剂对幽门螺杆菌诱导胃上皮细胞IL-8分泌的影响

目的：分析中国临床分离的幽门螺杆菌的cag致病岛的差异和不同激酶抑制剂对幽门螺杆菌诱导中国人胃上皮细胞IL-8分泌的影响。方法：在体外分别用中国临床分离的cagA^ cagE^ 、cagA^ cagE^ 、cagA^ cagE^ 、cagA^ cagE^ 的幽门螺杆菌与中国人胃上皮细胞MGC-803共培养,IL-8分泌用ELISA进行检测,比较蛋白激酶A、C、G和蛋白酪氨酸激酶的抑制剂对幽门螺杆菌诱导胃上皮细胞IL-8分泌的影响。结果：cagA^ cagE^ 幽门螺杆菌显增加了胃上皮细胞IL-8的分泌,cagA^ cagE^ 、cagA^ cagE^ 幽门螺杆菌作用次之,而cagA^ cagE^ 幽门螺杆菌不能增加胃上皮细胞IL-8的分泌。蛋白激酶A、C、G的抑制剂不能阻断幽门螺杆菌增加胃上皮细胞IL-8的分泌,而蛋白酪氨酸激酶的抑制剂阻断了幽门螺杆菌增加胃上皮细胞IL-8的分泌。结论：cagA^ cagE^ 幽门螺杆菌显增加了胃上皮细胞IL-8的分泌并且依赖于蛋白酪氨酸激酶的活性。     

Expression of LL-37 by human gastric epithelial cells as a potential host defense mechanism against Helicobacter pylori

BACKGROUND & AIMS : LL-37/human cationic antimicrobial peptide 18 (hCAP18) is a human cathelicidin with broad-spectrum antimicrobial, lipopolysaccharide binding, and chemotactic activities. This study examined the role of LL-37/hCAP18 in gastric innate immune defense by characterizing its constitutive and regulated expression by human gastric mucosa and its bactericidal activity against the gastric pathogen Helicobacter pylori. METHODS : LL-37/hCAP18 messenger RNA expression in normal and H. pylori -infected gastric mucosa and gastric epithelial cells was determined by in situ hybridization, real-time polymerase chain reaction, immunostaining, and immunoblot analysis. Bactericidal activity was measured by using a colony-forming unit assay. RESULTS : LL-37/hCAP18 messenger RNA and protein were expressed in a distinct distribution by surface epithelial cells as well as chief and parietal cells in the fundic glands of normal gastric mucosa. LL-37/hCAP18 was significantly increased in the epithelium and gastric secretions of H. pylori -infected patients, but not in individuals with non-H. pylori -induced gastric inflammation. Infection of cultured gastric epithelial cells with a wild-type but not an isogenic Delta cagE mutant strain of H. pylori increased LL-37/hCAP18 expression, indicating that H. pylori -induced regulation of LL-37/hCAP18 production required an intact type IV secretion system. LL-37, the C-terminal peptide of LL-37/hCAP18, alone or in synergy with human beta-defensin 1, was bactericidal for several H. pylori strains. CONCLUSIONS : These data indicate that H. pylori up-regulates production of LL-37/hCAP18 by gastric epithelium and suggest this cathelicidin contributes to determining the balance between host mucosal defense and H. pylori survival mechanisms that govern chronic infection with this gastric pathogen.