Effect of Helicobacter pylori cdrA on interleukin-8 secretions and nuclear factor kappa B activation

AIM:To investigate genetic diversity of Helicobacter pylori (H.pylori) cell division-related gene A (cdrA) and its effect on the host response.METHODS:Inactivation of H.pylori cdrA,which is involved in cell division and morphological elongation,has a role in chronic persistent infections.Genetic property of H.pylori cdrA was evaluated using polymerase chain reaction and sequencing in 128 (77 American and 51 Japanese) clinical isolates obtained from 48 and 51 patients,respectively.Enzyme-linked immunosorbent assay was performed to measure interleukin-8 (IL-8) secretion with gastric biopsy specimens obtained from American patients colonized with cdrA-positive or-negative strains and AGS cells cocultured with wild-type HPK5 (cdrA-positive) or its derivative HPKT510 (cdrA-disruptant).Furthermore,the cytotoxin-associated gene A (cagA) status (translocation and phosphorylation) and kinetics of transcription factors [nuclear factor-kappa B (NF-κB) and inhibition kappa B] were investigated in AGS cells co-cultured with HPK5,HPKT510 and its derivative HPK5CA (cagA disruptant) by western blotting analysis with immunoprecipitation.RESULTS:Genetic diversity of the H.pylori cdrA gene demonstrated that the cdrA status segregated into two categories including four allele types,cdrA-positive (allele types;Ⅰand Ⅱ) and cdrA-negative (allele types;Ⅲ and Ⅳ) categories,respectively.Almost all Japanese isolates were cdrA-positive (Ⅰ:7.8% and Ⅱ:90.2%),whereas 16.9% of American isolates were cdrA-positive (Ⅱ) and 83.1% were cdrA-negative (Ⅲ:37.7% and Ⅳ:45.5%),indicating extended diversity of cdrA in individual American isolates.Comparison of each isolate from different regions (antrum and corpus) in the stomach of 29 Americans revealed that cdrA status was identical in both isolates from different regions in 17 cases.However,12 cases had a different cdrA allele and 6 of them exhibited a different cdrA category between two regions in the stomach.Furthermore,in 5 of the 6 cases possessing a different cdrA category,cdrA-negative isolate existed in the corpus,suggesting that cdrA-negative strain is more adaptable to colonization in the corpus.IL-8 secretions from AGS revealed that IL-8 levels induced by a cdrA-disrupted HPKT510 was significantly lower (P < 0.01) compared to wildtype HPK5:corresponding to 50%-60% of those of wild-type HPK5.These data coincided with in vivo data that an average value of IL-8 in biopsy specimens from cdrA-positive and cdrA-negative groups was 215.6 and 135.9 pg/mL,respectively.Western blotting analysis documented that HPKT510 had no effect on CagA translocation and phosphorylation,however,nuclear accumulation of NF-κB was lower by HPKT510 compared to HPK5.CONCLUSION:Colonization by a cdrA-negative or cdrA-dysfunctional strain resulted in decreased IL-8 production and repression of NF-κB,and hence,attenuate the host immunity leading to persistent infection.

Ultraslim endoscopy with flexible spectral imaging color enhancement for upper gastrointestinal neoplasms

AIM:To conduct a preliminary study on the effect of flexible spectral imaging color enhancement (FICE) used in combination with ultraslim endoscopy by focusing on the enhanced contrast between tumor and non-tumor lesions. METHODS: We examined 50 lesions of 40 patients with epithelial tumors of the upper gastrointestinal tract before endoscopic submucosal dissection using ultraslim endoscopy with conventional natural color imag ing and with FICE imaging. We retrospectively invest igated the effect of the use of FICE on endoscopic diagn osis in comparison with normal light. RESULTS: Visibility of the epithelial tumors of the upper gastrointestinal tract with FICE was superior to normal light in 54% of the observations and comparable to normal light in 46% of the observations. There was no lesion for which visibility with FICE was inferior to that with normal light. FICE visualized 69.6% of hyperemic lesions and 58.8% of discolored lesions better than conventional endoscopy with natural color imaging. FICE sign if icantly improved the visibility of lesions with hyp ere mia or discoloration compared with normocolored lesions. CONCLUSION: This study suggests that the use of FICE would improve the ability of ultraslim endoscopy to detect epithelial tumors of the upper gastrointestinal tract.