Gene de virulência oipA de Helicobacter pylori como marcador molecular de gastropatias severas / Helicobacter pylori oipa virulence gene as a molecular marker of severe gastropathies

ABSTRACT Background: Helicobacter pylori is an etiologic agent of gastroduodenal diseases. The microorganism, considered a type I carcinogen, affects about 50% of the global population. H. pylori virulence factors are determinant for the clinical outcome of the infection. The outer inflammatory protein A (oipA) gene encodes an outer membrane adhesin and is related to severe gastropathies, such as gastric cancer. Objective: The aim of this study was to evaluate the association of the oipA gene with the severity of gastroduodenal diseases in dyspeptic patients in region Central Brazil. Methods: The polymerase chain reaction (PCR) was used to determine the presence of H. pylori. Samples positives were used for molecular screening of the oipA gene. Gastropathies were categorized as non-severe and severe diseases. Results: Approximately 68% of patients had H. pylori and 36% were infected with H. pylori oipA+ strains. Infection was significantly associated in patients aged over 44 years (P=0.004). However, there was no association between oipA and patients' age (P=0.89). Approximately 46% of patients infected with oipA+ strains had some severe illness. Gastric adenocarcinoma was the most frequent severe gastropathy. The H. pylori oipA genotype was inversely associated with the severity of gastroduodenal diseases (OR=0.247, 95%CI: 0.0804-0.7149 and P=0.007). Conclusion: The characterization of possible molecular markers will contribute to personalized medicine, impacting the prognosis of patients.

RESUMO Contexto: Helicobacter pylori é um agente etiológico de doenças gastroduodenais. O microrganismo, considerado cancerígeno tipo I, afeta cerca de 50% da população mundial. Os fatores de virulência do H. pylori são determinantes para o desfecho clínico da infecção. O gene da proteína inflamatória externa A (oipA) codifica uma adesina da membrana externa e está relacionado a gastropatias severas, como o câncer gástrico. Objetivo: O objetivo deste estudo foi avaliar a associação do gene oipA com a gravidade das doenças gastroduodenais em pacientes dispépticos na região Brasil Central. Métodos: A reação em cadeia da polimerase (PCR) foi utilizada para determinar a presença de H. pylori. Amostras positivas foram utilizadas para triagem molecular do gene oipA. As gastropatias foram categorizadas como doenças não severas e severas. Resultados: Aproximadamente 68% dos pacientes apresentaram H. pylori e 36% estavam infectados com cepas H. pylori oipA+. A infecção foi significativamente associada em pacientes com idade superior a 44 anos (P=0,004). No entanto, não houve associação entre oipA e a idade dos pacientes (P=0,89). Aproximadamente 46% dos pacientes infectados com cepas oipA+ tiveram alguma doença severa. O adenocarcinoma gástrico foi a gastropatia severa mais frequente. O genótipo oipA de H. pylori foi inversamente associado à gravidade das doenças gastroduodenais (OR=0,247, IC95%: 0,0804-0,7149 P=0,007). Conclusão: A caracterização de possíveis marcadores moleculares contribuirá para a medicina personalizada, impactando no prognóstico dos pacientes.

Interleukin 8 (-251 T>A) polymorphism in children and teenagers infected with Helicobacter pylori

Background Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the human stomach and causes a variety of gastric diseases. This study evaluated the correlations between the -251 (T>A) (rs4073) polymorphism of interleukin-8 (IL-8), the etiology of gastric disease, and H. pylori infection in pediatric and adolescent patients. Methods DNA samples were obtained from 285 gastric biopsies from pediatric patients. H. pylori was detected by PCR, whereas PCR-RFLP was used to characterize the -251 (T>A) polymorphism of IL-8. Results The histological analysis revealed the presence of gastritis in 158 patients (55.44%). H. pylori was found in 71 samples (24.9%). The -251 (T>A) polymorphism revealed that 58 (29.47%) samples were TT, 143 (50.18%) samples were TA, and 84 (20.35%) samples were AA. Conclusions Our findings suggest that IL8-251 A allele may be an important risk factor for the development of gastric disease when associated with H. pylori infection.(AU)

Interleukin 8 (-251 T>A) polymorphism in children and teenagers infected with Helicobacter pylori

Abstract Background Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the human stomach and causes a variety of gastric diseases. This study evaluated the correlations between the -251 (T>A) (rs4073) polymorphism of interleukin-8 (IL-8), the etiology of gastric disease, and H. pylori infection in pediatric and adolescent patients. Methods DNA samples were obtained from 285 gastric biopsies from pediatric patients. H. pylori was detected by PCR, whereas PCR-RFLP was used to characterize the -251 (T>A) polymorphism of IL-8. Results The histological analysis revealed the presence of gastritis in 158 patients (55.44%). H. pylori was found in 71 samples (24.9%). The -251 (T>A) polymorphism revealed that 58 (29.47%) samples were TT, 143 (50.18%) samples were TA, and 84 (20.35%) samples were AA. Conclusions Our findings suggest that IL8-251 A allele may be an important risk factor for the development of gastric disease when associated with H. pylori infection.

Lack of association among TNF-α gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of theTNF-α gene. Methods One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61♂ and 73♀, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF-α; was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2-ΔΔCT). Results The analysis revealed an increase in TNF-α gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF-α gene expression. Conclusions Helicobacter pylori induces a large increase in TNF-α expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF-α; pathway may play an important role in the progression from gastritis to gastric cancer(AU)

Lack of association among TNF-alfa gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of theTNF- gene. Methods One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61 and 73, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF- was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2-CT). Results The analysis revealed an increase in TNF- gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF- gene expression. Conclusions Helicobacter pylori induces a large increase in TNF- expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF- pathway may play an important role in the progression from gastritis to gastric cancer.

Association among H. pylori virulence markers dupA, cagA and vacA in Brazilian patients

Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.

Association among H. pylori virulence markers dupA, cagA and vacA in Brazilian patients

Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.

Polimorfismo da Interleucina-8 -251T>A e Helicobacter pylori / Interleukin-8 -251T>A polymorphism and Helicobacter pylori

Introdução: o Helicobacter pylori é um importante patógeno associado ao desenvolvimento de gastrite crônica, úlcera péptica e doenças gástricas. Vários autores relataram que a infiltração de células inflamatórias, incluindo neutrófilos, é um traço da patologia da mucosa gástrica associada com a infecção. Há evidências de que a inflamação está associada à gravidade das lesões gástricas. A interleucina 8 (IL-8), um membro da família das citocinas, é um ativador quimiotático de neutrófilos e linfócitos e tem sido descrito que o aumento dos níveis de IL-8 na mucosa gástrica pode estar associado com a infecção por H.pylori. Objetivos: os objetivos deste trabalho foram (i) caracterizar o polimorfismo da Interleucina-8 -251T>A (ii) e verificar a possível relação entre este polimorfismo e infecção por H.pylori. Métodos: cento e sessenta pacientes sintomáticos (com idade média de 48,7 anos) participaram do estudo: 107 pacientes positivos para H.pylori e 53 negativos, previamente diagnosticados por PCR. Os genótipos da IL-8 -251 T>A foram determinados através da reação em cadeia da polimerase (PCR) e utilização de enzimas de restrição (RFLP). Resultados e Conclusões: nossos resultados indicam que não há associação entre o polimorfismo da IL-8 -251 T>A e a infecção por H.pylori ou pelo gênero dos pacientes.

Background: Helicobacter pylori is an important pathogen associated with the development of chronic gastritis, peptic ulcer disease and gastric disease. Several authors reported that the infiltration of inflammatory cells, including neutrophils is the trace of the pathology of gastric mucosa, associated with the infection. There is high evidence that inflammation is associated with severity of gastric lesions. Interleukin-8 (IL-8), a member of cytokines family, is an activator and chemoattractant of neutrophils and lymphocytes. It has been reported that increased gastric mucosal levels of IL-8 is associated with H. pylori infection. Objective: the objectives of this paper were (i) characterize Interleukin-8 -251T>A polymorphism and (ii) to examine the possible relationship between this polymorphism and the H. pylori infection. Methods: one hundred and sixty patients, (with a mean age 48.7 years) presenting recurrent abdominal pain participated in the study: 107 H. pylori positives and 53 H. pylori negatives previously diagnosed by PCR. IL8 -251T>A genotypes were determined using a polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Results and Conclusions: our findings indicate that there is no association of IL-8 -251T>A with H. pylori-infected patients or gender of these patients and these conclusions were consistent with other reports from different population samples.

Interleukin- 8- 251T > a, interleukin -1α -889C > t and apolipoprotein e polymorphisms in Alzheimer's disease

An inflammatory process has been involved in numerous neurodegenerative disorders such as Parkinson's disease, stroke and Alzheimer's disease (AD). In AD, the inflammatory response is mainly located in the vicinity of amyloid plaques. Cytokines, such as interleukin-8 (IL-8) and interleukin-1α (IL-1α), have been clearly involved in this inflammatory process. Polymorphisms of several interleukin genes have been correlated to the risk of developing AD. The present study investigated the association of AD with polymorphisms IL-8 -251T > A (rs4073) and IL-1α-889C > T (rs1800587) and the interactive effect of both, adjusted by the Apolipoprotein E genotype. 199 blood samples from patients with AD, 146 healthy elderly controls and 95 healthy young controls were obtained. DNA samples were isolated from blood cells, and the PCR-RFLP method was used for genotyping. The genotype distributions of polymorphisms IL-8, IL-1α and APOE were as expected under Hardy-Weinberg equilibrium. The allele frequencies did not differ significantly among the three groups tested. As expected, the APOE4 allele was strongly associated with AD (p < 0.001). No association of AD with either the IL-1α or the IL-8 polymorphism was observed, nor was any interactive effect between both polymorphisms. These results confirm previous studies in other populations, in which polymorphisms IL-8 -251T > A and IL-1α-889C > T were not found to be risk factors for AD.

Helicobacter pylori detection in gastric biopsies, saliva and dental plaque of Brazilian dyspeptic patients

Helicobacter pylori is an important human pathogen that causes chronic gastritis and is associated with the development of peptic ulcer disease and gastric malignancies. The oral cavity has been implicated as a potential H. pylori reservoir and may therefore be involved in the reinfection of the stomach, which can sometimes occur following treatment of an H. pylori infection. The objectives of this paper were (i) to determine the presence of H. pylori in the oral cavity and (ii) to examine the relationship between oral H. pylori and subsequent gastritis. Gastric biopsies, saliva samples and dental plaques were obtained from 78 dyspeptic adults. DNA was extracted and evaluated for the presence of H. pylori using polymerase chain reaction and Southern blotting methods. Persons with gastritis were frequently positive for H. pylori in their stomachs (p < 0.0001) and there was a statistically significant correlation between the presence of H. pylori in gastric biopsies and the oral cavity (p < 0.0001). Our results suggest a relationship between gastric infection and the presence of this bacterium in the oral cavity. Despite this, H. pylori were present in the oral cavity with variable distribution between saliva and dental plaques, suggesting the existence of a reservoir for the species and a potential association with gastric reinfection.