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.