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

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

Luanna Munhoz Zabaglia¹, Mariane Avante Ferraz¹, Weendelly Nayara Pereira¹, Wilson Aparecido Orcini¹, Roger Willian de Labio², Agostinho Caleman Neto², Fernanda Wisnieski³, Juliana Garcia de Oliveira¹, Marilia de Arruda Cardoso Smith³, Spencer Luiz Marques Payão¹², Lucas Trevizani Rasmussen¹

1 Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP, Brazil.

2 Faculdade de Medicina de Marília, Rua Lourival Freire 240, 17519-050 Marília, SP, Brazil.

3 Universidade Federal de São Paulo, Rua Sena Madureira, 1500, 04021-001 São Paulo, SP, Brazil.

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

This study was approved by the Research Ethics Committee of Sacred Heart University (Universidade do Sagrado Coração) in Bauru, SP, Brazil (under registration n. 068/12).

Written informed consent was obtained from all patients or their legal guardians for publication of this case report.

Received: June 30, 2015; Revised: December 21, 2015; Accepted: December 30, 2015

LMZ, MAF, WNP, WAO, AC Neto and FW carried out the sample collection, DNA and RNA extraction, cDNA syntheses and molecular analysis. LMZ, RWL, JGO and MACS participated in the study design, performed the statistical analysis and provided technical support and scientific discussions. SLMP and LTR conceived the study, participated in its design, coordination and helped to draft the manuscript. All authors read and approved the final manuscript.