Auswahl der wissenschaftlichen Literatur zum Thema „Pylori“

Duodenogastric reflux (DGR) causes bile reflux gastritis (BRG) and may develop into gastric cancer. DGR is classified as primary in non-operated stomachs or secondary to surgical intervention. Primary DGR and Helicobacter pylori (H. pylori) infection are reportedly related. However, the mechanism is not fully understood. This study aimed to elucidate the relationship between H. pylori infection and pyloric incompetence in a non-operated stomach. A total of 502 non-operated participants who underwent an upper intestinal endoscopy were prospectively enrolled. Endoscopic findings (EAC, endoscopic atrophy classification; nodular gastritis; xanthoma; fundic gland polyp; and incompetence of pylorus), sex, age, gastrin, pepsinogen (PG) I and PG II levels were evaluated. PG I/PG II ratio, anti-H. pylori-Ab positivity, and atrophic gastritis status were significantly different between the normal and incompetent pylori (p = 0.043, <0.001, and 0.001, respectively). Open-type atrophic gastritis was significantly higher in the incompetent pylori. Incompetence of the pylorus and EAC were moderately correlated (Cramer’s V = 0.25). Multivariate analysis revealed that the presence of anti-H. pylori-Ab was the only independent factor associated with the incompetence of the pylorus, with an adjusted odds ratio of 2.70 (95% CI: 1.47–4.94, p = 0.001). In conclusion, pyloric incompetence was associated with H. pylori infection and moderately correlated to the severity of atrophic gastritis in non-operated stomachs.

With the exponential increase in research in the field ofHelicobacter pyloria paradigm shift has occurred. It is now recognized thatH pyloriis a chronic infection of the stomach causing inflammation. Some patients remain asymptomatic, while others may develop dyspepsia, duodenal or gastric ulcer, gastric cancer or a mucosa-associated lymphoid tissue lymphoma. However, the role ofH pyloriin contributing to nonulcer dyspepsia or nonsteroidal anti-inflammatory drug gastropathy remains controversial. An effective vaccine againstH pyloriis years away. Major interest has focused on the questions "who should be investigated and therefore treated" and "what is the latest gold standard for eradication ofH pylori"? In Europe, guidelines have been developed to help the practitioner answer these important questions. Canadian guidelines will soon be available. For persons with known peptic ulcer disease there should be unequivocal acceptance that the good clinical practice of eradicatingH pyloriwill result in substantial savings in health care expenses. The original 'classical triple therapy' (bismuth, metronidazole and tetracycline [BMT]) has now been surpassed by the combination of a proton pump inhibitor (PPI) plus two antibiotics (metronidazole plus clarithromycin; amoxicillin plus clarithromycin; or amoxicillin plus metronidazole), each given twice a day for one week. In Canada, the regimen of omeprazole plus one antibiotic (amoxicillin or clarithromycin) was approved recently but gives an eradication rate that is lower than the current target of 90%. According to the European (Mäastricht) recommendations, if a single treatment attempt with PPI plus two antibiotics fails, PPI plus BMT is recommended.

Helicobacter pylori (H. pylori) infection causes chronic gastritis, peptic ulcers and gastric cancer. Although H. pylori prevalence is decreasing worldwide, regional variations exist in Europe, with the lowest infection prevalence in Northern Europe, and the highest in Eastern and Southern Europe (1). Changes in the treatment recommendations and the increasing available evidence have justified the implementation of new recommendations since last Belgian consensus in 1998 (2). Several non-H. pylori Helicobacter species (NH.PYLORI-H), colonizing the stomach of domestic animals, also have the ability to cause gastric disease in humans, although to a lesser extent. These zoonotic NH. PYLORIH are not the subject of the current recommendations.

Helicobacter pylori is a major cause of the transdifferentiation into intestinal metaplasia that may develop gastric cancer. However, the molecular pathogenesis of this transdifferentiation is poorly understood. A SRY-related HMG box protein Sox2 is an essential transcription factor of organ development in brain, lung, and stomach. Our aim of this study was to investigate the mechanism responsible for regulation of Sox2 in host Th1-dominant response to H. pylori. Sox2 protein was immunohistochemically expressed in both human oxyntic and pyloric glands with H. pylori infection, but not in intestinal metaplasia. Western immunoblotting of gastric epithelial cell lines showed that IL-4, a Th2-related cytokine, dose dependently enhanced Sox2 expression among H. pylori infection-mediated cytokines. Small changes of Sox2 expression were observed after each treatment with IFN-γ, IL-1β, or TNF-α. IL-4-mediated Sox2 induction was suppressed by the inhibition of STAT6 activation with STAT6 RNA interference, and electrophoretic mobility shift assay indicated that activation of the Sox2 promoter by IL-4 occurred through the action of STAT6. Furthermore, H. pylori and IFN-γ inhibited the phosphorylation of STAT6, resulting in the suppression of IL-4-mediated Sox2 expression. Immunohistochemical analyses showed significantly the suppressed STAT6 activity in H. pylori-infected human gastric mucosa. Additionally, downregulation of Sox2 by knockdown experiments led to intestinal phenotype with expressions of Cdx2 and MUC2. These results suggest that H. pylori and IFN-γ interfere with the differentiation into oxyntic and pyloric glands by the downregulation of Sox2 on IL-4/STAT6 signaling, which may contribute to the transdifferentiation into intestinal metaplasia.

The effect of botulinum toxin type A (BTX-A) on rat pyloric myoelectrical activity in vivo and the content and distribution of substance P (SP) in pylorus were investigated, respectively, with electromyography, radioimmunoassay, and immunohistochemistry. A pair of electrodes for recording pyloric myoelectrical activity and a guide cannula for drug injection were implanted into the pylorus. The changes of pyloric myoelectrical activity were recorded followed vehicle, 10, 20, and 40 U/kg body mass of BTX-A injection. Pyloric tissues were dissected for radioimmunoassay and immunohistochemistry after recording. The 3 dosages of BTX-A injections caused the reduction of slow wave of pyloric myoelectrical activity in amplitude but not in frequency and the diminishment of spike activity in amplitude and spike burst. The inhibitory effect of 20 U/kg BTX-A was significantly different from that of 10 U/kg (p < 0.05), but not from the effect of 40 U/kg administration (p > 0.05). After BTX-A intrasphincteric injection, SP content was reduced in the pylorus, and cell number of SP-immunoreactivity was decreased more in myenteric nerve plexus of circular muscle and in mucosa of pylori. In conclusion, BTX-A inhibits pyloric myoelectrical slow activity in amplitude and spike activity and weakens pyloric smooth muscle contractility depending on threshold of dose or concentration. BTX-A-induced inhibition of pyloric myoelectrical activity implies a mechanism of inhibiting SP release from the autonomic and enteric nervous terminals in the pylorus.

Background. The aim of this study was to investigate the association between iron deficiency anemia andH. pyloriin patients with normal gastrointestinal tract endoscopy results.Materials and Methods. A total of 117 male patients with normal gastrointestinal tract endoscopy results were included in this retrospective study. The study and control groups included 69 and 48 patients with and without iron deficiency anemia, respectively. The prevalence ofH. pylori, the number of RBCs, and the levels of HGB, HTC, MCV, iron, and ferritin were calculated and compared.Results. There was no statistically significant difference found between the groups according to the prevalence ofH. pylori(65.2% versus 64.6%,P=0.896). Additionally, the levels of RBCs, HGB, HTC, MCV, iron, and ferritin in the patients in the study group were lower than those in the control group (P<0.05). Finally, there was no association between iron deficiency anemia andH. pylori(OR 1.02, Cl 95% 0.47–2.22, andP=0.943).Conclusion.H. pyloriis not associated with iron deficiency anemia in male patients with normal gastrointestinal tract endoscopy results.

AbstractA 40-year-old man with slightly depressed (0-IIc) type gastric cancer of the pyloric anterior gastric area underwent pre-operative screening for tetralogy of Fallot and endoscopic submucosal dissection (ESD) and was tested for Helicobacter pylori antigens and antibodies. Both tests were negative. He did not have a history of eradication. Pathological diagnosis of ESD showed a well-differentiated adenocarcinoma. The tumor was CD10-positive, MUC5AC-negative, and MUC6-confocal positive; it showed differentiation with gastrointestinal phenotype. Moreover, the tumor cells were lysozyme-positive, resembling Paneth cells. Mucosal glands exhibited intestinal metaplasia on the anal side of the tumor lesion. On the oral side of the tumor, metaplasia was non-existent, with normal pyloric glands present in the mucosal layer. The patient was not infected with H. pylori; however, intestinal metaplasia existed around the early gastric cancer. This suggested that the intestinal metaplasia occurred due to bile reflux, and the gastric neoplasia arose with the metaplasia without an H. pylori infection. This case may potentially help explain gastric cancer development in the absence of H. pylori infection.

Gastric polyps are often an incidental finding on upper gastrointestinal endoscopy, with an incidence up to 5%. The majority of gastric polyps are asymptomatic, occurring secondary to inflammation. Prior reviews discussed Helicobacter pylori (H pylori)–associated singular gastric polyposis; however, we present a rare and unusual case of recurrent multiple benign gastric polyposis post H pylori eradication resulting in intermittent gastric outlet obstruction. A 70-year-old independent male, Chinese in ethnicity, with a background of diabetes mellitus, hypertension, and a simple renal cyst presented with a combination of melena, anemia, and intermittent vomiting of partially digested food after meals. Initial gastroscopy was positive for H pylori; thus he was treated with H pylori eradication and proton pump inhibitors. Serial gastroscopy demonstrated multiple sessile gastric antral polyps, the largest measuring 4 cm. Histopathologic examination confirmed a benign hyperplastic lesion. Computed tomography identified a pyloric mass with absent surrounding infiltration or metastasis. A distal gastrectomy was performed, whereby multiple small pyloric polyps were found, the largest prolapsing into the pyloric opening, thus explaining the intermittent nature of gastric outlet obstruction. Such polyps often develop from gastric ulcers and, if left untreated, may undergo neoplasia to form malignant cells. A distal gastrectomy was an effective choice of treatment, taking into account the polyp size, quantity, and potential for malignancy as opposed to an endoscopic approach, which may not guarantee a complete removal of safer margins and depth. Therefore, surgical excision is favorable for multiple large gastric polyps with risk of malignancy.

Helicobacter pylori (H. pylori) is a 0.5–1 µm wide, 2–4 µm long, short helical, S-shaped Gram-negative microorganism. It is mostly found in the pyloric region of the stomach and causes chronic gastric infection. It is estimated that these bacteria infect more than half of the world’s population. The mode of transmission and infection of H. pylori is still not known exactly, but the faecal–oral and oral–oral routes via water or food consumption are thought to be a very common cause. In the last three decades, research interest has increased regarding the pathogenicity, microbial activity, genetic predisposition, and clinical treatments to understand the severity of gastric atrophy and gastric cancer caused by H. pylori. Studies have suggested a relationship between H. pylori infection and malabsorption of essential micronutrients, and noted that H. pylori infection may affect the prevalence of malnutrition in some risk groups. On the other hand, dietary factors may play a considerably important role in H. pylori infection, and it has been reported that an adequate and balanced diet, especially high fruit and vegetable consumption and low processed salty food consumption, has a protective effect against the outcomes of H. pylori infection. The present review provides an overview of all aspects of H. pylori infection, such as clinical features, treatment, and nutrition.

Background. There are several diagnostic methods forHelicobacter pylori (H. pylori)infection. A cost-effective analysis is needed to decide on the optimal diagnostic method. The aim of this study was to determine a cost-effective diagnostic method in patients with atrophic gastritis (AG).Methods. A decision-analysis model including seven diagnostic methods was constructed for patients with AG diagnosed by esophagogastroduodenoscopy. Expected values of cost and effectiveness were calculated for each test.Results. If the prevalence ofH. pyloriin the patients with AG is 85% and CAM-resistantH. pyloriis 30%, histology, stoolH. pyloriantigen (SHPAg), bacterial culture (BC), and urineH. pyloriantibody (UHPAb) were dominated by serumH. pyloriIgG antibody (SHPAb), rapid urease test (RUT), and urea breath test (UBT). Among three undominated methods, the incremental cost-effective ratios (ICER) of RUT versus SHPAb and UBT versus RUT were $214 and $1914, respectively. If the prevalence of CAM-sensitiveH. pyloriwas less than 55%, BC was not dominated, but itsH. pylorieradication success rate was 0.86.Conclusions. RUT was the most cost-effective at the current prevalence of CAM-resistantH. pylori. BC could not be selected due to its poor effectiveness even if CAM-resistantH. pyloriwas more than 45%.

O Helicobacter pylori (HP) constitui uma entidade fundamental quando nos reportamos à patologia gastro-duodenal. As indicações para a erradicação desta bactéria constituem, actualmente, uma das grandes controvérsias na área da Gastroenterologia. Com o objectivo principal de estabelecer o actual ponto de situação no que diz respeito às indicações para a erradicação do HP, realizámos uma revisão sistemática aprofundada do tema com base em artigos científicos de boa qualidade metodológica. Existem duas indicações inequívocas para efectuar o tratamento de erradicação do HP: a doença péptica ulcerosa e o linfoma MALT gástrico de baixo grau. Apesar da grande e continuada investigação nesta área, persistem ainda algumas dúvidas relativamente a determinadas situações clínicas em que o HP está envolvido como agente patogénico. São elas a dispepsia funcional, a doença de refluxo gastroesofágico e a utilização concomitante de anti-inflamatórios não esteróides. Nos doentes com anemia por deficiência de ferro inexplicada ou com púrpura trombocitopénica idiopática, recomenda-se que a infecção por HP seja investigada e tratada.

From 1994, Helicobacter pylori was classified by WHO (World Health Organization) as a class I carcinogen and its infection has been associated to gastroduodenal disease. It colonizes more than half of worldwide population, with a prevalent infection rate in developed countries. In spite of the majority of infected people are asymptomatic, around 20% develop severe pathologies like peptic ulcers and the 1% lymphoma of the mucosa-associated lymphoid tissue (MALT) and stomach cancer. This significant epidemiological study both of the unique characteristics of H. pylori inspired many scientists, as bacteriologist, gastroenterologists, cancer and pharmaceutical scientists to understand physio-pathological aspects of this bacterium, and also microbiologist, taxonomist, microbial ecologist and molecular biologist, for a more detailed molecular approach. H. pylori, a Gram negative, microaerophilic bacteria that colonize human gastric mucosa. It is not an acidophilus bacterium and even if the stomach lumen presents inhospitable condition for most microbes, it is able to survive for a short period, sufficient to enter in the highly viscous mucosa, reach gastric epithelium, and colonize the gastro-enteric tract. H. pylori colonization is mediated by a predominant virulence factor, the flagellar motility associated to chemotaxis. To avoid its discharge in the intestinal tract by peristalsis, the bacteria establish a persistent infection inside the viscous gastric mucus film that covers the gastric epithelium. A nickel containing enzyme, the urease, hydrolyzes the urea present in the stomach to ammonia and CO2, buffering the pH of the periplasm. The most severe clinical outcomes are always associated to cag+ strains. cag-PAI is defined as the “Cytotoxic Associated Genes Pathogenicity Island” and it consists of a characteristic chromosome, flanked by transposable elements. Another important virulent factor is the vacuolating cytotoxin A, known as VacA, which induces the formation of large cytoplasmic vacuoles in gastric cultured cell lines. Moreover the iron and nickel acquisition is essential grow factors and a large number of genes are responsible of this mechanism. While the development of an efficient vaccine against H. pylori is now the aim of many researchers, the search for new specific antibiotics as a new pharmaceutical target is required for the complete eradication of H. pylori. In this thesis has been investigate the structural and function role of different pathogenic proteins involved in the H. pylori colonization of human gastric mucosa. These potential drug targets have been cloned, 8 out of 11 were expressed in a heterologous expression system, after purification, 2 of them generate protein crystals and only one was possible to characterize the molecular structure. In particular it has been elucidated a possible physiological role of CeuE (HP1561), a Class III SPB (Substrate Binding Protein), crystalized with Ni(His)2 complex and it was determined its affinity to the complex by an in vitro approach. The H. pylori flagella play a key role during infection allowing the bacterium to move through the mucous layer. The H. pylori hook scaffolding protein FlgD were cloned, expressed, purified and crystalized. A study of other purified pathogenic H. pylori factors belonging to flagellar component apparatus and transcriptional factors involved in cellular stress response has been reported. To obtain these results, different experimental approaches has been used. Bioinformatics analysis of target proteins has been performed to predict the best candidates for a crystallographic study and for genetic construction design. Molecular cloning in plasmid vectors has been performed from PCR amplification. The expression conditions were optimized and performed in E. coli, a heterologous system. The solubility of recombinant proteins were checked and obtained also with protein refolding methods. Different purification techniques were used in order to obtain pure protein. Target characterization was performed due analytical gel filtration, UV spectroscopy, DLS (Dynamic Light Scattering) and CD (Circular Dichroism). The proteins were concentrated to crystallization trials. The protein crystals obtained were analyzed at ESRF synchrotron (Grenoble, France). Functional in vitro approaches were performed using fluorescence spectroscopy, SPR (Surface Plasmon Resonance) and Mass spectroscopy. In the second chapter is described the three dimensional structure of a H. pylori pathogenic protein crystalized in presence with its possible physiological substrate. HP1561 (CeuE) is a H. pylori protein predicted to be an ABC transporter component, periplasmic iron-bind transporter. Recently it was published that CeuE and fecDE genes of H. mustelae encode for a nickel and cobalt acquisition system. In Gram-negative bacteria, nickel uptake is guaranteed by multiple and complex systems that operate at the membrane and periplasmic level. H. pylori employs other yet uncharacterized systems to import the nickel required for the maturation of key enzymes, such as urease and hydrogenase. To understand this contradiction of the data about Ni2+ acquisition system in H. pylori CeuE was cloned, expressed, purified, crystallized and its structure determined. Identity between the sequences of the two Helicobacter is 44%. The two Histidine residues (H103 and H197), potentially involved in Siderophores/Ni2+ binding coordination in H. pylori CeuE, are partially conserved. The His corresponding to H. pylori position 103 is conserved, whilst His197 is replaced by a Leucine. In order to check, if this substitution influence the binding of siderophores/Ni2+, the mutant of H. pylori CeuE H197L was than produced and purified. The crystal structure of H. pylori CeuE has been determined at 1.65Å resolution using the SAD method, in Apo-form and in complex with Ni(His)2. It comprises two structurally similar globular domains, each consisting of a central five-stranded β-sheet surrounded by α-helices, an arrangement commonly classified as a Rossmann-like fold. Structurally, H. pylori CeuE belongs to the class III periplasmic substrate-binding protein. Crystallographic data, fluorescence binding assays and SPR analysis allow to exclude a role of the protein in the transport of VitB12, heme, enterobactin and isolated Ni2+ ions. On the contrary, the crystal structure of the protein/Ni(L-His)2 complex and dissociation constant obtained by SPR technique suggests that H. pylori CeuE binds and transport nickel in vivo thanks to the formation of a Ni2+/histidine complex or to some ligand that mimics it. In the third chapter is presented the study of FlgD, a flagellar component involved in the formation the extracellular complex, the flagellar hook. The motility of H. pylori is considered a colonization factor, due the fact that less motile strains are less able to colonize or survive in the host than full motile strains. In the flagellum machinery are involved more than 50 genomic genes for regulation and assembly. The three major components are the filament, the hook and the basal body. FlgD is not present when the flagellum is completed, but plays a key role during the assembly. Therefore, it has been classified as the hook-scaffolding protein, considering it also as the hook capping protein, interacting with FlgL and FlgK and the basal body rod – modification protein. In H. pylori G27 strain FlgD correspond to the gene hp0858 that was amplified from purified genomic DNA and cloned in an expression plasmid vector. The protein was produced in E. coli BL21 in reach medium ad it resulted to a soluble protein. DLS and analytical gel filtration confirm the oligomeric state of FlgD that resulted to be a tetramer in solution. The protein was concentrated to 30g/l and crystalized after a couple of month of incubation. The crystals had diffracted at 2.7Å of maximum resolution. For molecular replacement approach was used homology modeling. Different molecular models were built to fit experimental diffraction data. The secondary structure of the generated models was fitted with experimental CD spectra, where FlgD resulted to have around 12% of helices and 45% of β-sheets (190-260nm). Crystallographic statistics do not properly converged to a positive molecular refinement with the tested models. To solve FlgD structure are necessary crystals of recombinant Selenomethionine FlgD that was expressed, purified and crystalized. In the fourth chapter are reported H. pylori pathogenic proteins that had been characterized. These proteins could be divided in two groups, the first one of flagellar proteins and the second of cellular stress response factors, in collaboration with Professor V. Scarlato of the department of Biology of Bologna University. FliN is a cytosolic protein, localized in the C ring of the flagellar basal body. It interacts with the other two components FliM and FliG. Missense or mutation of fliN had been associated to non-motile strains. It has been reported that regulates the clockwise/counterclockwise switching of flagella. H. pylori FliN was cloned, expressed and purified from the inclusion body after refolding. Oligomerization after refolding was tested by DLS and analytical gel filtration. The protein resulted to be poly-disperse in solution and no protein crystals have been obtained. FliD is the filament capping protein and it was observed that interact with FliT that is not only a flagellar type III substrate specific export chaperone but also inhibits the expression of fliD thought its specific interaction with the master regulator FlhD4C2 complex. In order to analyze possible structure of the co-crystalized FliD-FliT, it was plan to co-express these proteins. Both were cloned with a different affinity purification system, but only FliT was possible to express and purify from inclusion bodies. The CD spectra presented a strong β-sheet component in the secondary structure. DLS and analytical gel filtration revealed that this protein is poly-disperse in solution and no protein crystals were be obtained. FlgN is a type III secretion chaperone and it has been reported to interact with the two hook junction protein FlgK and FlgL preventing the protein proteolysis when the flagellum is not assembled. These proteins have been cloned in different type of plasmid vectors for a co-expression experiment, but only FlgN was properly expressed in E. coli. Recombinant FlgN was purified by Ni-IMAC and resulted to be soluble in solution. The protein was characterized by analytical gel filtration, DLS and CD. The protein resulted to be a monomer in solution with a 30% of not defined secondary structure (190-260nm). FlgN was concentrated and different crystallization conditions were tested. In the latter group there are three proteins related to Heat shock response, produced when bacteria encounter stress such as the elevated temperatures, ethanol, H2O2 and acid. It was demonstrated that H. pylori Hsps play an important role during the host infection. HrcA and HspR are negative repressor of groESL and dnaK machinery. HrcA activity depends by the presence of HspR, because it is demonstrated that HrcA is not able to bind DNA in absence of HspR. These two proteins were expressed in E. coli and purified by Ni-IMAC affinity. During the concentration step, these proteins present a solubility limit influenced by the concentration. Mutagenesis of a Cys in HspR and detergent solubility screening with HrcA has been performed, but no suitable protein for crystallization trials has been obtained. Hp1026 is a gene present in the same operon of HspR (hp1025). The function of this gene has not been reported. From sequence homology was possible to identify a helicase domain and ATP-binding domain. This protein, ORF, has been expressed in E. coli and purified by Ni-IMAC affinity. Analytical gel filtration and CD has been performed to characterize this protein. The protein was a dimer in solution with a 35% of α-helices component. Crystallization trials have been performed at different protein concentrations and also in presence of its possible cofactor, ATPγS. No crystals have been obtained in tested condition. Appendix: Structural and functional study on a human protease S1P/ SKI1 The study of human S1P/SKI1 protease was performed in collaboration with Professor S. Kunz of the Institute of Microbiology, University Hospital Center and university of Lausanne, Switzerland. S1P/SKI-1 is a serine protease that belongs to the mammalian family of Proprotein Convertases (PC). The aim of this family member is to mediate the activation of different important substrates for cell live. Among these proteases, S1P has been shown to have unique substrate specificity, preferring cleavage after non-basic amino acids. Known S1P cellular targets are SREBP-2, involved in the biosynthesis and uptake of lipids and cholesterol, BDNF, ATF-6 and the surface glycoprotein of viruses belonging to the family of Arenaviridae. S1P is 118 kDa multi-domain protein; two regions of S1P have been investigated, the "Prodomain", involved in the regulation of S1P catalytic activity, and the so called "catalytic domain", which include the residues responsible for the cleavage reaction itself. Moreover it was analyzed an inactive mutant of cS1P: H249A. Also for ProD was chosen one constructs (ProD_AB and ProD_AC) involved in the affinity of the protease substrate. Hence, the sequences corresponding to the domains were synthesized as optimized genes for the expression in E. coli and sub-cloned in expression plasmids in order to obtain C-term His-tagged fusion proteins. These constructs have been expressed in E. coli, purified by Ni-IMAC and positive fractions have been collected and concentrated in order to perform crystallization trials. Unfortunately no protein crystals have been obtained in tested condition. To elucidate the role of a mutated variant of the cleavage site “C” of Pro Domain, it was performed a mass spectrometry analysis. Secreted S1P/SKI1 mutant C was purified from culture medium of HEK293 cell line was isolated by IMAC-Co. The sample, loaded in RP-HPLC, was denatured in 6 M Guanidine-HCl. The chromatographic fractions corresponding to the major HPLC peaks were dried out in a speed-vac concentrator and directly injected in the ESI source. Mass measurements were performed with a quadrupole-TOF spectrometer. Analysis of mass spectra, compared with wild-type form of S1P, allows generating a preliminary Pro Domain auto-processing profile.
Dal 1994 il batterio Helicobacter pylori è stato classificato come organismo cancerogeneno di prima classe e la sua infezione è associata a patologie gastroduodenali. Più di metà della popolazione mondiale ne è infettata con una maggiore prevalenza nei paesi sviluppati. Nonostante la maggior parte dei casi le infezioni sono asintomatiche, il 20% sviluppa gravi patologie come ulcere peptiche e nell’1% dei casi genera linfomi e gastro carcinomi. L’incidenza e le caratteristiche di questo batterio hanno ispirato batteriologi, gastroenterologi, oncologi e farmacologi per indagare gli aspetti fisiopatologici legati all’infezione, così come microbiologi, ecologi, biologi molecolari hanno cercato i fattori di virulenza coinvolti in nell’infezione. H. pylori è un batterio microaerofilico Gram negativo che colonizza la mucosa gastrica. Non è un batterio acidofilo, anche se è in grado di sopravvivere nel lume dello stomaco per un breve periodo necessario per raggiungere le cellule epiteliali spostandosi attraverso la mucosa gastrica. La colonizzazione è mediata da fattori di virulenza predominanti come la motilità flagellare associata alla chemiotassi. Per evitare che sia espulso dal tratto intestinale dalla peristalsi, il batterio H. pylori stabilisce un’infezione cronica. L’ureasi, che è un enzima nickel dipendente, che idrolizza l’urea presente in ammoniaca e CO2 tamponando il pH acido dello stomaco. I casi più gravi sono associati ai ceppi che esprimono l’isola di patogenicità cag-PAI, che consiste in un cromosoma delimitato da elementi trasponibili. Un altro importante fattore di virulenza è la tossina vacuolizzante VacA, che induce la formazione di vacuoli citoplasmatici. Anche il meccanismo di acquisizione di ferro e nickel è fondamentale per la colonizzazione batterica e dunque finemente regolata da un gran numero di geni. Lo sviluppo di un vaccino e nuovi antibiotici nutrono una costante ricerca di nuovi possibili bersagli farmacologici, necessari per completa ed efficiente eradicazione del batterio H. pylori. In questa tesi sono stati analizzati il ruolo e la struttura di alcune proteine patogenetiche del H. pylori. Questi potenziali target farmacologici sono stati clonati, otto su undici sono stati espressi in un sistema eterologo, due proteine di quelle purificate hanno generato cristalli e di una sola ne è stata definita la struttura molecolare. In particolare è stato definito un possibile ruolo della proteina CeuE (HP1561), appartenete alla famiglia delle proteine che legano un substrato, cristallizzata in presenza del complesso Ni(His)2 e definita l’affinità con lo stesso in vitro. Del flagello, che svolge un ruolo chiave durante l’infezione, ne è stata studiata la proteina coinvolta nella formazione dell’uncino FlgD che è stata clonata, espressa, purificata e cristallizzata. Inoltre è stato riportato anche uno studio di altri fattori del flagello e di alcune proteine coinvolte nella risposta allo stress cellulare. Per ottenere tali risultati sono stati utilizzati approcci differenti. Per individuare le migliori proteine candidate per uno studio cristallografico e progettare costrutti funzionali sono state effettuate predizioni bioinformatiche. Gli amplificati di PCR sono stati clonati in vettori plasmidici. Le condizioni di espressione sono state ottimizzate e fatte in E. coli, un sistema di espressione eterologo. La solubilità delle proteine ricombinanti è stata analizzata e ottenuta anche mediante refolding. Sono stati usati diversi sistemi di purificazione per ottenere un buon grado di purezza. Per la caratterizzazione proteica sono state usate come tecniche la gel filtrazione analitica, spettroscopia UV, DLS (Dynamic Light Scattering) e dicroismo circolare. Le proteine sono state concentrate e sottoposte a esperimenti di cristallizzazione. I cristalli sono stati analizzati al sincrotrone ESRF (Grenoble, France). Spettroscopia di fluorescenza, SPR (surface plasmon resonance) e spettroscopia di massa sono le tecniche utilizzate per la caratterizzazione In Vitro. Nel secondo capitolo viene decritta la struttura tridimensionale di una proteina patogenetica di H. pylori, cristallizzata in presenza del suo possibile substrato fisiologico. HP1561 (CeuE) è una proteina di H. pylori annotata come componente periplasmatico di un trasportatore ABC che lega e trasporta il ferro. Recentemente è stato pubblicato chele ceuE e fecDE di H. mustelae codificano per proteine coinvolte nel acquisizione del nickel e cobalto. Nei Gram negativi, l’acquisizione del nickel è garantita da sistemi di proteine che operano a livello di membrana e periplasmatico. Per l’acquisizione del nickel, l’ H. pylori integra diversi sistemi non ancora caratterizzati, necessari per la maturazione di enzimi chiave come l’ureasi e l’idrogenasi. Per chiarire tale contraddizione nel sistema di acquisizione del nickel nell’H. pylori, CeuE è stata clonata, espressa, purificata, cristallizzata e la sua struttura è stata risolta. L’identità di sequenza tra i due Helicobacter (pylori e mustelae) è del 44%. Le due Istidine (H103 e H197), potenzialmente coinvolte nel legame di coordinazione del sistema sideroforo/Ni2+ nel H. pylori CeuE, risultano essere parzialmente conservate. L’His corrispondente alla His103 di H. pylori è conservata, mentre His197 è sostituita da una Leucina. Al fine d’identificare se tale mutazione possa influenzare il legame sideroforo/Ni2+, è stato prodotto e purificato il mutante H. pylori CeuE H197L. La struttura molecolare di H. pylori CeuE è stata determinata con una risoluzione di 1.65 Å mediante metodo SAD, sia nella forma apo, che in complesso col Ni(His)2. Essa è costituita da due domini globulari simili, ognuno costituito da cinque foglietti-β circondati da α-eliche, comunemente classificato come Rossman fold. Strutturalmente H. pylori CeuE appartiene alla Classe III della famiglia di proteine che legano un substrato specifico (SBPs). Dati cristallografici, saggi di fluorescenza e analisi all’SPR ci permettono di escludere il coinvolgimento della proteina nel trasporto della VitB12, eme, entrobactina, e ioni Ni2+ isolati. Al contrario la struttura della proteina/complesso Ni(His)2 e le costanti di dissociazione ottenute mediante SPR suggeriscono che H. pylori CeuE lega e trasporta il nickel in vivo mediante il complesso Ni2+/His o altro ligando che lo mima. Nel terzo capitolo viene presentato lo studio su FlgD, una proteina flagellare fondamentale nella formazione di un complesso extracellulare, l’uncino del flagello. La motilità dell’H. pylori è considerata un fattore di colonizzazione, attraverso il quale ceppi meno motili hanno minori possibilità di colonizzare e sopravvivere nell’ospite di ceppi più motili. Per la formazione del flagello sono coinvolti più di 50 geni per la regolazione e l’assemblaggio delle varie componenti. Le tre componenti principali sono il filamento, l’uncino e il corpo basale. FlgD non è presente quando il flagello è maturo, ma ha un ruolo chiave durante l’assemblaggio. Perciò, è stato classificato come proteina necessaria per l’impalcatura dell’uncino (hook scaffolding protein), considerata anche proteina di testa dell’uncino (capping protein) in quanto interagisce con FlgL, FlgK e le proteine del corpo basale. Nel ceppo H. pylori G27, FlgD corrisponde al gene hp0858 che è stato amplificato dal DNA genomico purificato e clonato in un vettore plasmidico. La proteina è stata prodotta in E. coli BL21 e la proteina è risultata essere solubile. Gel filtrazione analitica e misure al DLS confermano il suo stato di oligomerizzazione, che risulta essere un tetramero in soluzione. La proteina è stata concentrata fino a 30 g/l e cristallizzata dopo un paio di mesi d’incubazione. I cristalli hanno diffratto a una risoluzione massima di 2.7 Å. Per la sostituzione molecolare è stata usata la tecnica del homology modelling. Sono stati costruiti diversi modelli molecolari per fittare i dati sperimentali. La struttura secondaria dei modelli generati è stata comparata con gli spettri di dicroismo circolare, dove FlgD è risultata essere composta da un 12% di eliche e complessivamente da un 45% di foglietti beta (190-260nm). Le statistiche cristallografiche non hanno dato convergenza positiva negli esperimenti di sostituzione molecolare con i modelli testati. Per risolvere la struttura di FlgD sono necessari cristalli di FlgD derivatizzata con Selenometionine, che è stata espressa, purificata e cristallizzata. Nel quarto capitolo sono riportate le proteine patogenetiche di H. pylori che sono state caratterizzate in questa tesi. Queste proteine possono essere divise in due gruppi, il primo delle proteine flagellarli ed il secondo delle proteine coinvolte nella risposta allo stress cellulare in collaborazione con il Prof. V. Scarlato del dipartimento di Biologia dell’università di Bologna. FliN è una proteina citosolica localizzata nell’anello C del corpo basale del flagello ed interagisce con altri due componenti FliM e FliG. Mutazioni missenso di fliN sono state associate a ceppi non-motili ed è stato riportato che regola la rotazione oraria/antioraria del flagello. H. pylori FliN è stata clonata, espresso e purificata dai corpi d’inclusione dopo refolding. Lo grado di oligomerizzazione è stato analizzato mediante DLS e gel filtrazione analitica. La proteina è risultata essere polidispersa i soluzione e non sono stati ottenuti cristalli di proteina. FliD è la proteina “capping” del filamento cellulare ed è stato osservato che interagisce con FliT, che non è solo un chaperon substrato specifico del sistema III di esporto flagellare, ma inibisce anche l’espressione di fliD attraverso l’interazione con il complesso FlhD4C2. Al fine di analizzare la struttura del complesso FliD-FliT, è stata pianificata la co-espressione di queste proteine. Entrambe sono state clonate con un sistema di purificazione differente, ma solo la purificazione di FliT è stata possibile dai corpi d’inclusione. Lo spettro di dicroismo circolare ha rivelato una forte componente di foglietti-β nella struttura secondaria. Secondo le misure di DLS e gel filtrazione analitica FliT è polidispersa in soluzione e perciò non stati ottenuti cristalli della stessa. FlgN è una proteina del sistema secrezione tipo III ed è stato osservato che interagisce in maniera specifica con le proteine di giunzione dell’uncino con il filamento FlgK ed FlgL, prevenendone la proteolizzazione prima della maturazione del flagello. Queste proteine sono state clonate in differenti tipi di vettori plasmidici, ma solo FlgN è stata efficacemente espressa in E. coli. FlgN ricombinante è stata purificata mediante Ni-IMAC è risultata essere solubile. La proteina è stata caratterizzata con gel filtrazione analitica, DLS e CD. La proteina è un monomero in soluzione con un 30% di struttura secondaria non definita (190-260 nm). FlgN è stata concentrata e sottoposta a test di cristallizzazione. Nell’ultimo gruppo ci sono tre proteine HSPs (Heat Shock Response), prodotte dal batterio quando incontra stress come elevate temperature, etanolo, H2O2 e acidi. E’ stato accurato che le HSPs di H. pylori svolgono un ruolo importante durante l’infezione dell’ospite. HrcA e HspR reprimono la trascrizione di groESL e dnaK. L’attività di HrcA è influenzata dalla presenza di HspR, in quanto è stato dimostrato che HrcA non è in grado di legare il DNA in assenza di HspR. Queste due proteine sono state espresse in E. coli e purificate con Ni-IMAC. Durante le fasi di concentrazione hanno mostrato un limite di solubilità. Mutagenesi mirata sul costrutto di HspR e screening di detergenti su HrcA sono hanno migliorato il sistema, senza però riuscire ad ottenere una condizione ottimale per la formazione di cristalli di proteina. HP1026 (ORF) è un gene presente nello stesso operone di HspR (hp1025), ma con funzione non nota. Dall’analisi della sequenza è stato identificato un dominio con attività elicasica ed un dominio legante l’ATP. La proteina è stata espressa in E. coli e purificata con Ni-IMAC. Per la caratterizzazione sono state effettuate gel filtrazione analitica e dicroismo circolare. La proteina risulta essere un dimero in soluzione con un 35% di α-elica. I test di cristallizzazione son stati effettuati scrinando diverse concentrazioni e anche in presenza del possibile cofattore, ATPγS in forma non idrolizzabile. Nessun cristallo è stato ottenuto dalle condizioni testate. Appendice: Studio strutturale e funzionale della proteasi umana S1P/SKI1 Lo studio di questa proteasi umana è stato effettuato in collaborazione con il Prof. S. Kunz dell’Istituto di Microbiologia, del Centro Universitario Ospedaliero e dall’ Univ. Di Lausanne, Svizzera. S1P/SKI1 è una serina proteasi della famiglia delle Proprotein Convertasi (PCs). Lo scopo di membri di questa famiglia è quello di mediare l’attivazione di diversi importanti substrati per la vita cellulare. Tra queste proteasi, S1P presenta una specificità di substrato, con un sito di taglio dopo un residuo non basico. Tra i target cellulari di S1P sono stati identificati SREBP-2, coinvolto nella biosintesi dei lipidi e del colesterolo, BDNF, ATF-6 e glicoproteine superficiali di virus appartenenti alla famiglia delle Arenaviridae. S1P pesa 118kDa ed è una proteina multidominio; quindi 2 regioni di S1P sono state studiate, il “Prodomain” (ProD) che regola l’attività catalitica, ed il “cathalytic domain” (cS1P) che include i residui responsabili per la reazione proteasica. Inoltre è stato analizzato un mutante inattivo (cS1P_H249A) e due costrutti per il dominio di regolazione (ProD_AB e ProD_AC). Le sequenze nucleotidiche dei corrispettivi costrutti sono state sintetizzate come geni ottimizzati per l’espressione in E. coli e subclonati in vettori plasmidici per l’espressione ottenendo proteine in fusione con una coda di 6-His. Questi costrutti sono stati espressi in E. coli, purificati con Ni-IMAC e le frazioni positive sono state raccolte e concentrate per test di cristallizzazione. Sfortunatamente non sono stati ottenuti cristalli di proteina nelle condizioni testate. Per chiarire il ruolo di una variante mutata nel sito di taglio “C” del dominio di regolazione è stata effettuata una analisi di spettrometria di massa. La proteina secreta S1P mut C (sS1P_MutC, 116kDa) è stata purificata dal medium di coltura di una linea di HEK293 trasfettate e isolata con Co-IMAC. Il campione è stato denaturato in Guanidinio 6M e caricato in HPLC. Le frazioni corrispondenti ai picchi predominanti sono stati essiccati ed iniettati in spettrometro di massa (ESI-TOF). L’analisi delle masse, confrontate con la forma nativa (sS1P_WT) ha permesso di generare un profilo preliminare del pattern di processamento del dominio di regolazione (ProD) with a quadrupole-TOF spectrometer. Analysis of mass spectra, compared with wild-type form of S1P, allows generating a Pro Domain auto-processing profile.

Introdução: O Helicobacter pylori adquiriu grande importância durante as últimas décadas, ao ser reconhecido como um importante patogénio que infeta uma grande parte da população humana. Esta bactéria, localizada na mucosa gástrica, apresenta uma relação causal com algumas patologias, tais como: carcinoma gástrico, úlcera péptica, entre outras. A sua erradicação representa um grande desafio para os clínicos. O aumento gradual da falha do tratamento obriga a utilizar novos esquemas terapêuticos e a procurar novas soluções. As taxas de eficácia de erradicação do Helicobacter pylori têm vindo a diminuir, pois a resistência aos antibióticos, nomeadamente à claritromicina, está a aumentar, tornando-se assim no principal fator para a falência do tratamento. A presente dissertação pretende efetuar uma revisão sistemática com base em publicações científicas relacionadas com a eficácia da terapêutica de erradicação do Helicobacter pylori. Métodos: Foram pesquisadas publicações indexadas nas bases de dados Pubmed, Elsevier, Wiley e B-On, na biblioteca eletrónica da Faculdade de Ciências da Saúde da Universidade da Beira Interior. Utilizaram-se os seguintes termos no título: efficacy, therapeutic ou therapy, helicobacter pylori, durante o período compreendido entre 01/01/2012 e 26/03/2013. Foram selecionados dez publicações para análise. Resultados: Dos dez estudos selecionados foram encontrados esquemas de primeira, segunda e terceira linha, onde os regimes utlizados foram terapia tripla, quádrupla sequencial, sequencial modificada e concomitante, variando a duração de tratamento entre os 5, 7, 10 e 14 dias. Na primeira linha de tratamento o esquema que apresentou mais eficácia com 96,5% utilizou uma terapia quádrupla concomitante, na segunda linda 93,6% com uma terapia tripla e por fim, na terceira linha 89,5% também com uma terapia tripla. Devido à heterogeneidade dos esquemas apresentados nas publicações não foi possível nenhuma análise estatística. Alguns estudos documentaram a resistência aos antibióticos, que variou entre os 23,4% a 78,7% ao metronidazole e entre 0% a 91,7% à claritromicina. Os efeitos adversos major variaram de 0,5% a 4,6% enquanto os minor variaram de 21,8% até 80%. Conclusão: Na primeira linha de tratamento, a terapia tripla de sete dias deve ser repensada e as terapias sequencial e concomitante são eficazes. Em relação à terapêutica de segunda linha, deve-se utilizar uma quinolona e terapia concomitante, se esta não foi utilizada na primeira linha, ou então uma terapia tripla de 14 dias. A terapia de terceira linha não necessita obrigatoriamente de ser orientada pelo teste de sensibilidade antibiótica para erradicar a bactéria. Diversos fatores influenciam a eficácia do tratamento, nomeadamente a resistência aos agentes antimicrobianos e a adesão do paciente à terapêutica.

Aquesta Tesi Doctoral té com objectius principals l’estudi d’Helicobacter pylori en mostres aquàtiques de Catalunya, en aigües procedents de sistemes dentals de consultes de dentistes, en saliva i en femtes de pacients amb símptomes gastrointestinals mitjançant el mètode de la PCR. També es va estudiar la supervivència d’Helicobacter pylori en aigua dolça usant un model de laboratori aplicant diferents tècniques d’anàlisi i es va interpretar el canvi de morfologia, la viabilitat i la culturabilitat de la bactèria així com la detecció i quantificació del seu ADN durant un període de temps concret. Per aconseguir aquests objectius, primer es va escollir la llet descremada al 40% v/v com a millor crioprotector i el medi agar Columbia suplementat amb 5% de sang desfibrinada de cavall com a medi de cultiu. Durant el desenvolupament de la tesi es va millorar la tècnica de PCR escollida inicialment basada amb l’estudi de Clayton i col•laboradors (1992) on s’usaven els iniciadors HPU1 i HPU2 en la PCR pel gen ureA, gen estructural de l’enzim ureasa. La tècnica de la hibridació seguida per aquests investigadors es va substituir per una segona PCR ja que aquesta permetria obtenir resultats més ràpidament. En aquesta PCR semiimbricada es va introduir un tercer iniciador intern, HPUI1, i mantenint HPU2 com a extern. Pel gen 16S rRNA, gen usat per a la detecció del gènere Helicobacter, es van usar els iniciadors 1F i 1R per a la primera PCR i els 1F i 2R per a la PCR semiimbricada. El mètode d’extracció escollit en aquest treball basat en partícules de sílice i tiocianat de guanidina descrit per Boom i col., (1990) i l’optimització de les barreges de reacció de les PCR semiimbricades pel gen ureA i 16S rRNA van permetre detectar 50 UPF/mL i 2-20UFC/mL, respectivament. Es va determinar la presència de H.pylori en mostres fecals humanes aplicant dos mètodes: mètode antigènic HpSA i l’amplificació del gen ureA. Amb el mètode molecular es va detectar la presència de ADN de H. pylori en 12 mostres i va mostrar un 75% de coincidència amb els resultats obtinguts amb el mètode antigènic HpSA. També es va determinar la presència de H. pylori a aigües amb diferent de nivell de contaminació fecal. Es va amplificar ADN d’aquesta espècie en un 30% de les mostres d’aigua residual, un 8,34% de les mostres d’aigua de riu de Catalunya i no es va detectar en aigua de font. L’estudi de supervivència de H. pylori a l’aigua en la foscor i a 7ºC es va demostrar que el recompte de bacteris i el número de genomes es manté constant durant tot el període d’estudi, 21 dies. La detecció per PCR també va ser positiva i constant durant aquest període. No obstant això, les cèl•lules només es van mantenir cultivables fins al sisè dia d’emmagatzematge. També es va observar una conversió morfològica de les cèl•lules bacterianes passant de la forma espiral a cocal amb el pas del temps. L’estudi de la morfologia cel•lular en un tall vertical d’una colònia d’H. pylori de 4 dies va mostrar la coexistència de cèl•lules amb morfologia bacil•lar i coccal. L’anàlisi de la saliva de 31 persones sanes va evidenciar la presència d’aquest bacteri en la boca de 6% de la població analitzada. La anàlisi feta amb la PCR semiimbricada per al gen 16S rRNA va identificar la presència d’aquest gen en 19 persones però la seqüenciació dels amplicons del gen ureA només va confirmar la presència de H. pylori en tres mostres. L’anàlisi de 31 mostres d’aigua procedents de les corresponents cadires no va mostra la presència del patogen.
This thesis has as main objectives the study of Helicobacter pylori in water samples from Catalonia, saliva and human feces using the PCR method. Also studied survival, morpholgy, viability and culturability of Helicobacter pylori in water. We first chose skim milk at 40% v / v as cryoprotectant and Columbia agar supplemented with 5% horse blood desfibrinada as a medium. We used a seminested PCR for ureA gene with HPU1 and HPU2 primers for the first PCR and HPUI1 and HPU2 for the second PCR. By gene 16S rRNA, we used the 1F and 1R primers for the first PCR and 1F and 2R for the second PCR. Using a silica and guanidine extraction method and optimization of the seminested PCR reaction mixtures for urea and 16S rRNA genes were detected 50 UPF / mL and 2-20UFC/mL respectively. H.pylori was detected in 12 human fecal samples. DNA of H.pylori was amplified in 30% of samples of wastewater, a 8.34% of the samples of river water in Catalonia and was not detected in spring water. The bacterial count and the number of H.pylori genomes remains constant throughout the study period, 21 days water in the dark at 7 ° C. The detection by PCR was also positive and constant during this period. The cells remained culturable only until the sixth day of storage. We observed morphological conversion of bacterial cells through the spiral to cocal over time. The study of cell morphology in a vertical section of a colony of H.pylori showed the coexistence of cells with bacillary and coccal morphology. The analysis of saliva from 31 healthy individuals showed the presence of this bacterium in the mouth of 6% of the analyzed population but we urea only confirmed the presence of H.pylori in three samples by sequencing.

Currently, one of the most promising areas in bacteriology is the study of the bacterium Helicobacter pylori. New studies show a link between H. pylori and some liver diseases, but their exact mechanisms and connections are still not fully understood. Despite this, studies of H. pylori and its association with liver diseases remain relevant to this day. This article presents an analysis of the association of H. Pylori with liver diseases.

Одними из ключевых промоторов в регуляции каскада воспалительных медиаторов являются тучные клетки, обладающие широким арсеналом биологически активных веществ. В патогенезе гастрита, ассоциированного с H. pylori принимают активное участие различные виды иммунокомпетентных клеток - макрофаги, нейтрофилы, эозинофилы, дендритные клетки, Т- и В-лимфоциты, а также тучные клетки. Антигенпредставляющие свойства тучных клеток представляют интерес в аспекте взаимодействия с Helicobacter pylori (H. Pylori)

Велика ли роль инфекции Helicobacter pylori на патогенез неалкогольной жировой болезни печени (НАЖБП)? Последние данные свидетельствуют о наличии их взаимосвязи [1, 2]. Однако до сих пор данная тема остается под вопросом. Цель данной работы - исследовать возможную связь и клиническое значение Helicobacter pylori в патогенезе неалкогольной жировой болезни печени. Is the role of Helicobacter pylori infection on the pathogenesis of non-alcoholic fatty liver disease (NAFLD) significant? Recent data indicate the presence of their relationship [1, 2]. However, until now, this topic remains in question. The aim of this work is to investigate the possible relationship and clinical significance of Helicobacter pylori in the pathogenesis of non-alcoholic fatty liver disease

Introdução: A gastrite crônica é principalmente causada pelo hipercloridrismo no piloro por infecção pelo Helicobacter pylori. Essa bactéria é um bacilo flagelado espiralado que se localiza sobre o epitélio da área antro-piloro. Nessa região, altera a fisiologia local e inibe o feedback negativo, inativando as células D e induzindo a hipercloridria. A virulência do H. pilory é baseada em 4 fundamentos: Flagelos: mobilidade no muco; Urease: eleva o pH gástrico; Adesinas: aderência às células foveolares (glândulas gástricas) – presente na biópsia e fator determinante para o diagnóstico e Toxinas: CagA (úlcera e câncer associado – metaplasia intestinal). Objetivos: O presente estudo visa verificar os fatores associados com o diagnóstico de gastrite crônica e a presença do H. pylori e demonstrar a importância da prevenção e tratamento da doença. Material e métodos: Este trabalho trata-se de uma revisão bibliográfica, que visa demonstração de características sobre manifestação clínica da gastrite associada ao H. pylori baseada em estudos passados. Para a realização do estudo, foram utilizados livros e artigos encontrados em sites acadêmicos como Google acadêmico e Scielo. Resultado: O Helicobacter pylori causa gastrite ao estimular a produção de citocinas pró-inflamatórias e destruir diretamente as células epiteliais. A gastrite é dividida em duas categorias, aguda e crônica, ambas com diferentes graus de descamação da superfície epitelial gástrica e diferentes graus de infiltração inflamatória. Na fase aguda, pode haver casos leves sem grandes alterações inflamatórias, enquanto em casos mais graves a inflamação pode ter sangramento adicional ou mesmo erosões da mucosa. A inflamação crônica da mucosa causada pelo Helicobacter pylori reduz a secreção ácida, levando à hipoacidez, além de reduzir a secreção de pepsina, contribuindo na proliferação bacteriana e na persistência da doença, aumentando o risco de mutações genômicas. Conclusão: A gastrite é uma patologia caracterizada por alterações histológicas na mucosa gástrica, na qual se observa infiltração de células inflamatórias. É a lesão mais comum que acomete o estômago. Pode-se concluir que múltiplas etiologias interagem para o aparecimento da gastrite crônica. Em palavras derradeiras, deve-se manter uma nutrição adequada ao longo da vida como método profilático contra o aparecimento de gastrite e o Helicobacter pylori.

Review question / Objective: Is gastric helicobacter pylori infection related to periodontal diseases? Condition being studied: Therefore, the aim of this systematic review and meta-analysis was to identify and analyze clinical studies to determine the direct correlation between Helicobacter Pylori gastric infection andPeriodontal Disease. Study designs to be included: Clinical studies that provided data on Helicobacter Pylori infection in both the stomach and oral cavity, confirmed by polymerase chain reaction (PCR), rapid urease test (RUT) or enzyme-linked immunosorbent assay (ELISA). Clinical studies that associated PD with Helicobacter Pylori. The diagnosis of PD was confirmed ac-cording to the diagnostic criteria in periodontology.