Helicobacter pylori adhesion to gastric epithelial cells is mediated by glycan receptors

Helicobacter pylori adhesion to gastric epithelial cells constitutes a key step in the establishment of a successful infection of the gastric mucosa. The high representation of outer membrane proteins in the bacterial genome suggests the relevance of those proteins in the establishment of profitable interactions with the host gastric cells. Gastric epithelial cells are protected by a mucous layer gel, mainly consisting of the MUC5AC and MUC6 mucins. In addition to this protective role, mucins harbor glycan-rich domains that constitute preferential binding sites of many pathogens. In this article we review the main players in the process of H. pylori adhesion to gastric epithelial cells, which contribute decisively to the high prevalence and chronicity of H. pylori infection. The BabA adhesin recognizes both H-type 1 and Lewis b blood-group antigens expressed on normal gastric mucosa of secretor individuals, contributing to the initial steps of infection. Upon colonization, persistent infection induces an inflammatory response with concomitant expression of sialylated antigens. The SabA adhesin mediates H. pylori binding to inflamed gastric mucosa by recognizing sialyl-Lewis a and sialyl-Lewis x antigens. The expression of the BabA and SabA adhesins is tightly regulated, permitting the bacteria to rapidly adapt to the changes of glycosylation of the host gastric mucosa that occur during infection, as well as to escape from the inflammatory response. The growing knowledge of the interactions between the bacterial adhesins and the host receptors will contribute to the design of alternative strategies for eradication of the infection.

Comparative proteomics analysis of chronic atrophic gastritis: changes of protein expression in chronic atrophic gastritis without Helicobacter pylori infection

Chronic atrophic gastritis (CAG) is a very common gastritis and one of the major precursor lesions of gastric cancer, one of the most common cancers worldwide. The molecular mechanism underlying CAG is unclear, but its elucidation is essential for the prevention and early detection of gastric cancer and appropriate intervention. A combination of two-dimensional gel electrophoresis and mass spectrometry was used in the present study to analyze the differentially expressed proteins. Samples from 21 patients (9 females and 12 males; mean age: 61.8 years) were used. We identified 18 differentially expressed proteins in CAG compared with matched normal mucosa. Eight proteins were up-regulated and 10 down-regulated in CAG when compared with the same amounts of proteins in individually matched normal gastric mucosa. Two novel proteins, proteasome activator subunit 1 (PSME1), which was down-regulated in CAG, and ribosomal protein S12 (RPS12), which was up-regulated in CAG, were further investigated. Their expression was validated by Western blot and RT-PCR in 15 CAG samples matched with normal mucosa. The expression level of RPS12 was significantly higher in CAG than in matched normal gastric mucosa (P < 0.05). In contrast, the expression level of PSME1 in CAG was significantly lower than in matched normal gastric mucosa (P < 0.05). This study clearly demonstrated that there are some changes in protein expression between CAG and normal mucosa. In these changes, down-regulation of PSME1 and up-regulation of RPS12 could be involved in the development of CAG. Thus, the differentially expressed proteins might play important roles in CAG as functional molecules.

Relationship of IL-1 and TNF-&#945; polymorphisms with Helicobacter pylori in gastric diseases in a Brazilian population

It is well known that the risk of development of gastric cancer (GC) in Helicobacter pylori-infected patients depends on several factors. Thus, the aim of this study was to investigate the effect of proinflammatory cytokine gene polymorphisms for IL-1&#946;, IL-1RN and TNF-&#945; on the development of GC in a Brazilian population. A total of 202 biopsies obtained from Brazilian patients with chronic gastritis and GC were included in the study. Infection with H. pylori cagA+ was determined by the polymerase chain reaction (PCR) as previously described. IL-1&#946;, IL-1RN and TNF-&#945; polymorphism genotyping was performed by restriction fragment length polymorphism PCR. Associations between gene polymorphisms, clinical diseases and virulence markers were evaluated using either the &#967;�� test or the Fisher exact test. Our results demonstrated that the IL-1&#946; -511 C/C and IL-1&#946; -511 C/T alleles were associated with chronic gastritis in H. pylori-positive patients (P = 0.04 and P = 0.05, respectively) and the IL-1&#946; -511 C/C genotype was associated with GC (P = 0.03). The frequency of IL-1RN alleles from patients with chronic gastritis and GC indicated that there was no difference between the genotypes of the groups studied. Similar results were found for TNF-&#945; -308 gene polymorphisms. Our results indicate that the IL-1&#946; -511 C/C and C/T gene polymorphisms are associated with chronic gastritis and GC development in H. pylori-infected individuals.

The efficacy of moxifloxacin-based triple therapy in treatment of Helicobacter pylori infection: a systematic review and meta-analysis of randomized clinical trials

Recent evidence shows that moxifloxacin could exert an antimicrobial effect against Helicobacter pylori in both in vitroand in vivo models. To systematically evaluate whether moxifloxacin-containing triple therapy could improve eradication rates and reduce side effects in first-line or second-line anti-H. pyloritreatment, eligible articles were identified by searches of electronic databases. We included all randomized trials comparing moxifloxacin-based triple therapy with standard triple or quadruple therapy during H. pylori eradication treatment. Statistical analysis was performed with Review Manager 5.0.10. Subanalysis/sensitivity analysis was also performed. We identified seven randomized trials (n=1263). Pooled H. pylori eradication rates were 79.03% (95%CI: 75.73-82.07) and 68.33% (95%CI: 64.44-72.04) for patients with moxifloxacin-based triple therapy or with standard triple or quadruple therapy, respectively (intention-to-treat analysis). The odds ratio (OR) was 1.82 (95%CI: 1.17-2.81), the occurrence of total side effects was 15.23% (95%CI: 12.58-18.20) and 27.17% (95%CI: 23.64-30.92) for groups with or without moxifloxacin, and the summary OR was 0.45 (95%CI: 0.26-0.77). In subgroup analyses, we noted that the second-line eradication rate in the moxifloxacin group was significantly higher than that in the quadruple therapy group (73.33 vs 60.17%, OR: 1.78, 95%CI: 1.16-2.73, P<0.001). However, there was no difference in first-line eradication treatment. Findings from this meta-analysis suggest that moxifloxacin-based triple therapy is more effective and better tolerated than standard triple or quadruple therapy. Therefore, a moxifloxacin-based triple regimen should be used in the second-line treatment of H. pylori infection.

Efficacy of a quadruple therapy regimen for Helicobacter pylori eradication after partial gastrectomy

We aimed to evaluate the effectiveness and safety of bismuth-containing quadruple therapy plus postural change after dosing for Helicobacter pylori eradication in gastrectomized patients. We compared 76 gastric stump patients with H. pylori infection (GS group) with 50 non-gastrectomized H. pylori-positive patients who met the treatment indication (controls). The GS group was divided into GS group 1 and GS group 2. All groups were administered bismuth potassium citrate (220 mg), esomeprazole (20 mg), amoxicillin (1.0 g), and furazolidone (100 mg) twice daily for 14 days. GS group 1 maintained a left lateral horizontal position for 30 min after dosing. H. pylori was detected using rapid urease testing and histologic examination of gastric mucosa before and 3 months after therapy. Mucosal histologic manifestations were evaluated using visual analog scales of the updated Sydney System. GS group 1 had a higher prevalence of eradication than the GS group 2 (intention-to-treat [ITT]: P=0.025; per-protocol [PP]: P=0.030), and the control group had a similar prevalence. GS group 2 had a lower prevalence of eradication than controls (ITT: P=0.006; PP: P=0.626). Scores for chronic inflammation and activity declined significantly (P<0.001) 3 months after treatment, whereas those for atrophy and intestinal metaplasia showed no significant change. Prevalence of adverse reactions was similar among groups during therapy (P=0.939). A bismuth-containing quadruple therapy regimen plus postural change after dosing appears to be a relatively safe, effective, economical, and practical method for H. pylori eradication in gastrectomized patients.

Detecci��n sensible de Helicobacter pylori en placa dentobacteriana y saliva de pacientes periodontalmente comprometidos por Luis Alberto Henric Trevi��o.

Tesis (Maestr��a en Ciencias Odontol��gicas con Especialidad en Periodoncia) U.A.N.L. Facultad de Odontolog��a, 2001.

Determinaci��n de la expresi��n in vivo e in vitro de los receptores TLR-4 y -5 durante la infecci��n por Helicobacter pylori

Tesis (Maestr��a en ciencias con orientaci��n en Microbiolog��a m��dica) U.A.N.L. Facultad de Medicina, 2006.

Presencia de helicobacter pylori en placa dental de la poblaci��n infantil que acude al posgrado de Odontopediatr��a de la Facultad de Odontolog��a de la U.A.N.L.

Tesis (Maestr��a en Ciencias Odontol��gicas con Especialidad en Odontopediatr��a) UANL, 2012.

Detecci��n molecular de helicobacter pylori en agua y alimentos.

Tesis (Doctor en Ciencias con Especialidad en Microbiolog��a) UANL, 2012.

Aislamiento y caracterizaci��n de compuestos derivados de plantas de la familia agavaceae con efecto antimicrobiano sobre helicobacter pylori

Tesis (Doctor en Ciencias con acentuaci��n en Qu��mica de Productos Naturales) UANL, 2014.

Esquema secuencial con moxifloxacina de primera l��nea en el tratamiento del helicobacter pylori: estudio piloto

INTRODUCCI��N: El ��xito de erradicaci��n del H. pylori con las terapias convencionales ha disminuido a niveles inaceptables. Se buscan ��ptimos esquemas terap��uticos con excelentes tasas de erradicaci��n. OBJETIVO: Cuantificar los desenlaces cl��nicos evaluados como efectividad, adherencia y seguridad, de una terapia secuencial de primera l��nea con Esomeprazol, Moxifloxacina, Amoxicilina y Tinidazol para la erradicaci��n individual del H. pylori. METODOLOG��A: Estudio prospectivo no controlado, piloto, abierto, ��nico centro. Consecutivamente se incluir��n adultos con prueba microbiol��gica positiva para H. pylori y s��ntomas disp��pticos. Los pacientes recibir��n un r��gimen de tratamiento de 10 d��as que consistir�� los 5 primeros d��as de (Esomeprazol 40 mg, bd; Amoxicilina 1 g, bd). Del d��a 6 a 10 (Esomeprazol 40 mg, bd ; Tinidazol 500 mg, bd y Moxifloxacina 500 mg, bd). Se realizar�� una prueba de ant��geno en materia fecal, para evaluar la efectividad terap��utica al menos a las 4 semanas de finalizar el tratamiento. RESULTADOS: 38 de 42 pacientes completaron el estudio. La tasa de erradicaci��n fue de 87% (Intervalo de Confianza (IC) 95% (75,5 ��� 98,5%) en an��lisis por protocolo (PP), y 79% (IC) 95% (65 ��� 93%) en an��lisis por intenci��n de tratar (ITT). La adherencia al tratamiento fue del 95% (40 pacientes), de los pacientes que ingresaron al estudio 48% presentaron al menos un efecto secundario menor principalmente diarrea y nauseas. CONCLUSIONES: Diez d��as de terapia secuencial basada en moxifloxacina proporciona tasas de erradicaci��n ��ptimas, con una buena adherencia y efectos secundarios leves y transitorios.

O potencial da PCR em tempo real no diagn��stico da infec����o por helicobacter pylori

H. pylori �� um microrganismo respons��vel por gastrites e implicado, em associa����o com outros factores, na ��lcera gastroduodenal e no cancro g��strico. O diagn��stico da infec����o por microrganismo pode realizar-se recorrendo a m��todos invasivos atrav��s da obten����o de uma bi��psia g��strica obtida por endoscopia digestiva alta e a m��todos n��o invasivos. Nenhum dos m��todos, desenvolvido at�� hoje, constitui o m��todo ideal. Todos eles possuem as suas vantagens e desvantagens consoante a situa����o em que s��o aplicados. A reac����o de polimeriza����o em cadeia (PCR) conduziu a uma modifica����o fundamental no campo da biologia molecular, abrindo novos horizontes nas ci��ncias m��dicas e biol��gicas. Apesar da cultura de H. pylori a partir de bi��psia g��strica continuar a ser o m��todo de refer��ncia para o diagn��stico da infec����o por esta bact��ria, ela apresenta inconvenientes que podem ser ultrapassados pela utiliza����o da PCR, como sejam o longo per��odo para a obten����o de resultados e o respeito de condi����es estritas de transporte da bi��psia g��strica. Recentemente foi desenvolvido um protocolo baseado no principio da PCR em tempo real, utilizando o aparelho LightCycler Roche Diagnostics. Este protocolo permite a obten����o de um resultado de detec����o da presen��a de H. pylori na bi��psia g��strica assim como do seu perfil de susceptibilidade aos macr��lidos. A PCR em tempo real �� dotada de uma grande sensibilidade e especificidade, rapidez de obten����o de resultados o que aliado �� sua capacidade de detec����o de muta����es respons��veis pela resist��ncia dos microrganismos aos antibi��ticos faz com que esta t��cnica seja a metodologia do futuro no diagn��stico das doen��as infecciosas.