Showing 4 results for Latifi-Navid
Saeid Latifi-Navid, Shiva Mohammadi , Saber Zahri ,
Volume 71, Issue 11 (February 2014)
Abstract
Background: Helicobacter pylori has been classified as the class I carcinogenic agent by world health organization. Colonization of the human stomach with H. pylori is a risk factor for gastroduodenal diseases. The secreted vacA toxin is an important H. pylori virulence factor that causes multiple alterations in gastric epithelial cells and T cells. Several families of vacA alleles have been described, and H. pylori strains containing certain vacA types (s1 and m1) are associated with an increased risk of gastric disease, compared to strains containing other vacA types (s2 and m2). We examined the association between H. pylori vacA s alleles and gastroduodenal diseases in Iran.
Methods: A total of 149 H. pylori strains were obtained from patients with gastritis, peptic ulcer, and gastric cancer referring to endoscopy units of several cities in Iran. Biopsy culture and DNA extraction were performed and the frequency of vacA s alleles was investigated by using PCR amplification. Linear regression and binary logistic regression models were used to analyze the association between vacA (vacuolating cytotoxin A) s alleles and gastroduodenal diseases.
Results: There was no significant association between the frequency of vacA s alleles and gastroduodenal diseases (gastritis or peptic ulcer disease and gastric adenocarcinoma (P> 0.05)).
Conclusion: It is proposed that the H. pylori vacA s1 genotype could not be considered as an important determinant of gastroduodenal diseases in Iranian population and probably if s1 allele is associated with other virulence alleles of this gene, it will cause diseases.
Seyedeh Zahra Bakhti, Saeid Latifi-Navid , Saber Zahri ,
Volume 72, Issue 9 (December 2014)
Abstract
Helicobacter pylori (H. pylori) is the causative agent in development of gastroduode-nal diseases, such as chronic atrophic gastritis, peptic ulcers, mucosa associated lym-phoid tissue (MALT) lymphoma, and gastric cancer. H. pylori has been associated with inflammation in cardia, showing the fact that infection with this bacterium could also be a risk factor for gastric cardia cancer. Gastric cancer is the fourth most common cancer worldwide. This is the second leading cause of cancer-related deaths, and ap-proximately 700,000 people succumb each year to gastric adenocarcinoma. It has been estimated that 69% of the Iranian population currently harbor H. pylori infection. The prevalence of duodenal ulcer and gastric cancer is high in Iranian populations. However, this has been largely influenced by geographic and/or ethnic origin. Epidemi-ology studies have shown that host, environmental, and bacterial factors determine the outcome of H. pylori infection. The bacterium contains allelic diversity and high genet-ic variability into core- and virulence-genes and that this diversity is geographically and ethnically structured. The genetic diversity within H. pylori is greater than within most other bacteria, and its diversity is more than 50-fold higher than that of human DNA. The maintenance of high diversification makes this bacterium to cope with particular challenges in individual hosts. It has been reported that the recombination contributed to the creation of new genes and gene family. Furthermore, the microevolution in cagA and vacA genes is a common event, leading to a change in the virulence phenotype. These factors contribute to the bacterial survival in acidic conditions in stomach and protect it from host immune system, causing tissue damage and clinical disease. In this review article, we discussed the correlation between H. pylori virulence factors and clin-ical outcomes, microevolution of H. pylori virulence genes in a single host, microevolu-tion of H. pylori during primary infection and progression of atrophic gastritis to ade-nocarcinoma, and H. pylori infection status in Iran. Finally, we put forward the hy-pothesis that if the pattern of nucleotide sequence evolution shifts from recombination (r) to mutation (m) and the r/m ratio is reduced, bacterial pathogenicity may be re-duced while maintaining the bacterial life. However, this hypothesis should be further studied with future experiments.
Batool Mottaghi , Reza Safaralizadeh , Morteza Jabbarpour Bonyadi, Saeid Latifi-Navid, Mohammad Hossien Somi, Majid Mahdavi ,
Volume 72, Issue 9 (December 2014)
Abstract
Background: Helicobacter pylori vacA (vacuolating toxin A) gene is comprised of mid- (m), intermediate- (i) and signal-regions. Recently, the vacA-i region genotype has been suggested to be a better predictor of disease severity than either the s- or m-region. The main aim of the present study was to determine the associations of i region poly-morphisms of vacA gene with gastric cancer (GC) and peptic ulcer disease (PUD) in Azerbaijan Province patients.
Methods: A number of 89 patients were enrolled. The biopsy samples were taken from patients referring to the endoscopy units of Imam Reza and Shahid Madani Hospitals, Tabriz, Iran from August 2012 to May 2013. The genotype frequencies of vacA-i1 and i2 in were studied using polymerase chain reaction (PCR).
Results: The frequency of vacA-i1 and i2 was 51.68% and 48.31%, respectively. The genotypic frequency of vacA-i1 in patients with GC (21/24, 87.5%) was significantly higher than in those with non-atrophic gastritis, NAG (19/48, 39.58%). In contrast, the genotypic frequency of vacA-i2 in patients with NAG, PUD, and GC was 60.42%, 64.70%, and 14.28%, respectively. The results of multiple linear and logistic regression analyses confirmed the intensity of correlation of vacA-i1 allele with GC compared with control group (NAG). No significant correlation was found between the vacA-i-region alleles and PUD risk.
Conclusion: We have proposed that the H. pylori vacA-i1 genotype could be an im-portant biomarker for predicting the gastric cancer risk in Azerbaijan Province in Iran. However, due to the difference in the allelic frequency of this gene in H. pylori strains from different parts of the world, the vacA-i1 genotype usefulness in predicting the gas-trointestinal diseases is dependent to the geographic origin of the strains.
Esmat Abdi , Saeid Latifi-Navid , Hamid Latifi-Navid , Saber Zahri, Abbas Yazdanbod ,
Volume 76, Issue 6 (September 2018)
Abstract
Gastric cancer (GC) is the second leading cause of cancer-related deaths worldwide. It has been proposed that the specific genotypes of Helicobacter pylori (H. pylori) are the causative agents in the development of gastroduodenal diseases, such as chronic atrophic gastritis, peptic ulcerations, and GC. However, disease progression to GC occurs in only a small proportion of infected patients. Recently, we identified a novel polymorphic site in the 3ʹ-end region of H. pylori vacA gene. The vacA c1 genotype increased the risk of GC. This association was independent of and larger than the associations of the m-, i-, and d-type of vacA or cagA status with GC. Therefore, treatment of H. pylori infection may be an effective way to prevent GC. Expression of cytokines and their associations with inflammatory responses has been shown. Several cytokine polymorphisms, such as IL-1B, IL-8, IL-10, and TNF-α have been considered as risk factors for GC. It has been shown that the interaction of bacterial genotypes and host factors plays an essential role in developing GC. Several altered molecular pathways are involved in the pathogenesis of GC. Micro-RNAs are small, non-coding RNAs of 18-25 nucleotides in length that regulate the expression of target mRNAs. Expression pattern of cancer cells is different compared with the normal cells. Micro-RNAs plays a critical role in apoptosis and classified in two groups: pro- and anti-apoptotic agents. Recent studies have confirmed the oncogenic or tumor suppression role of micro-RNAs in cancer cells. They play a significant role in the GC cell physiology and tumor progression, by translational suppression of target genes. These small RNAs have therefore emerged as a new type of GC biomarker with immeasurable clinical potential. Generally, a variety of micro-RNAs involved in different stages of cancer, including tumorigenesis, angiogenesis, and metastasis. Considering to this issue more than 50% of cancers can be cured, if they were diagnosed in the early stages. Hence, identifying the biomarkers of GC could play an important role in prevention, early diagnosis and rapid treatment of patients. In this review article, we have reviewed the latest findings about bacterial and tissue biomarkers of GC
