Phylogenetic analysis, based on EPIYA repeats in the cagA gene of Indian Helicobacter pylori, and the implications of sequence variation in tyrosine phosphorylation motifs on determining the clinical outcome

Fecal Helicobacter pylori glmM and 16S rRNA genes correlate with serum TNF-α and IL-1β cytokine fluctuations

The proinflammatory cytokines of TNF-α and IL-1β have been reported to be increased in gastric mucosal surfaces in people with Helicobacter pylori infection. Accordingly, this study was conducted to investigate the relationship between the presence of H. pylori genes and the serum oscillations of these cytokines. In this study, DNA was first extracted from the stool samples of infected individuals and used as DNA template to investigate the presence of glmM and 16S rRNA genes in PCR. The ELISA assay was employed to examine serum levels of TNF-α and IL-1β cytokines. According to statistical analysis, there was a significant correlation between the presence of glmM and 16S rRNA genes in the stool samples of infected persons and the serum oscillations of TNF-α and IL-1β cytokines. At the end of study and analysis of the data in case group with HPSAg+, 47.6% of the glmM gene and 23.6% of the 16S rRNA gene were positive. In addition, a significant correlation was observed between the presence of glmM and 16S rRNA genes in the stool specimens of infected individuals and the serum levels of TNF-α and IL-1β cytokines (p < 0.05). Considering the results, it can be concluded that fluctuations in the amount of HPSA, TNF-α, and IL-1β in H. pylori infection depend on the presence of glmM and 16S rRNA genes. The presence of glmM and 16S rRNA in the stool sample increases by boosting the response level to stool antigen (HPSA), IL-1β, and TNF-α, suggesting the prognosis of the disease with a bacterial virulence form using stool tests.

Characterizing Helicobacter pylori cagA in Myanmar

BACKGROUND/AIMS

Differences in the Helicobacter pylori infection rate are not sufficient to clarify the dissimilarity of gastric cancer incidence between Myanmar and its neighboring countries. To better understand this trend, the H. pylori virulence gene cagA was characterized in Myanmar.

METHODS

Glutamate-proline-isoleucine-tyrosine-alanine (EPIYA) patterns and CagA multimerization (CM) motifs of cagA genotypes were examined by performing polymerase chain reactions and DNA sequencing.

RESULTS

Of 69 tested H. pylori strains, cagA-positive patients had significantly more severe histological scores in their antrum than cagA-negative patients. Sequence analysis revealed that 94.1% of strains had Western-type cagA containing an EPIYA motif (92.6%) or EPIYT motif (6.4%). The intestinal metaplasia scores in the antral of patients infected with the ABC and ABCC types of cagA were significantly higher than those of patients with AB-type cagA. Interestingly, in patients infected with H. pylori, 46.3% of strains with three EPIYA motifs contained two identical Western-typical CM motifs, and these patients showed significantly higher antrum inflammation scores than patients infected with two identical nontypical-CM motif strains (p=0.02).

CONCLUSIONS

In Myanmarese strains, Western-type cagA was predominant. The presence of CM motifs and the proportion of multiple EPIYA-C segments might partially explain the intermediate gastric cancer risk found in Myanmar.

Five-year monitoring of considerable changes in tyrosine phosphorylation motifs of the Helicobacter pylori cagA gene in Iran

CagA is a major virulence factor of Helicobacter pylori involved in host cell modulation. The C-terminal part of CagA containing the EPIYA motifs is highly variable and is important for the biological activity of the protein. The aim of this study was consideration of the changes in cagA tyrosine phosphorylation motifs (TPMs) of H. pylori. A set of 302 H. pylori DNA samples from the Iranian population from 2006 to 2011 was selected for the proposed study. The cagA gene and its TPMs were assessed by using polymerase chain reaction (PCR) and specific primers. The prevalence of the cagA gene in our study ranged from 91.43% to 97.06% (with an average of 95.03%). Out of the cagA-positive samples, the prevalence of TPMs A and B increased from 12.5% and 23.44% to 71.2% and 63.63%, respectively. Also, the prevalence of samples infected with Western and East Asian types of H. pylori ranged from 64.06% to 5.73% for the Western type and 17.19% to 51.59% for the East Asian type. Overall, our results showed a high prevalence of the cagA gene. Also, it seems that cagA TPMs of H. pylori is undergoing a change from the Western type to the East Asian type in Iran.

Distinct repeat motifs at the C-terminal region of CagA of Helicobacter pylori strains isolated from diseased patients and asymptomatic individuals in West Bengal, India

BACKGROUND

Infection with Helicobacter pylori strains that express CagA is associated with gastritis, peptic ulcer disease, and gastric adenocarcinoma. The biological function of CagA depends on tyrosine phosphorylation by a cellular kinase. The phosphate acceptor tyrosine moiety is present within the EPIYA motif at the C-terminal region of the protein. This region is highly polymorphic due to variations in the number of EPIYA motifs and the polymorphism found in spacer regions among EPIYA motifs. The aim of this study was to analyze the polymorphism at the C-terminal end of CagA and to evaluate its association with the clinical status of the host in West Bengal, India.

RESULTS

Seventy-seven H. pylori strains isolated from patients with various clinical statuses were used to characterize the C-ternimal polymorphic region of CagA. Our analysis showed that there is no correlation between the previously described CagA types and various disease outcomes in Indian context. Further analyses of different CagA structures revealed that the repeat units in the spacer sequences within the EPIYA motifs are actually more discrete than the previously proposed models of CagA variants.

CONCLUSION

Our analyses suggest that EPIYA motifs as well as the spacer sequence units are present as distinct insertions and deletions, which possibly have arisen from extensive recombination events. Moreover, we have identified several new CagA types, which could not be typed by the existing systems and therefore, we have proposed a new typing system. We hypothesize that a cagA gene encoding higher number EPIYA motifs may perhaps have arisen from cagA genes that encode lesser EPIYA motifs by acquisition of DNA segments through recombination events.

Botulinum A toxin injection. Failures in clinical practice and a biomechanical system for the study of toxin-induced paralysis

Botulinum A toxin injection has great utility in the treatment of essential blepharospasm and other facial spasm disorders. Several investigators have noted the failure of botulinum toxin injections to relieve lid spasm in occasional patients and a decrease in effectiveness or duration of effect following multiple injections in other patients. We reviewed the charts of 30 consecutive patients presenting for the evaluation or treatment of facial dystonia. Of 20 patients who had received multiple injections of botulinum toxin, 10 patients were felt to be treatment failures. A new biomechanical system was developed to investigate the duration and degree of paralysis induced in the gastrocnemius muscle of the rat. Animals were treated with four sequential injections at 6-week intervals to the same muscle, resulting in muscle atrophy and an increase in the duration and degree of muscle paralysis, contrary to clinical findings in humans. The review of patient data confirms that, for many patients, repeated injection of botulinum toxin results in a decrease in duration and degree of effect despite an increased toxin dose. An opposite effect was noted in our experimental model because of progressive muscle atrophy.