Laboratory of Research in Bacteriology, Faculdade de Medicina, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190/216, Belo Horizonte, MG, 30130-100, Brazil.
Int J Med Microbiol. 2011 Mar;301(3):225-8. doi: 10.1016/j.ijmm.2010.08.019. Epub 2010 Nov 2.
The dupA of Helicobacter pylori has been suggested as a virulence marker associated with the development of duodenal ulcer disease. However, the studies performed in different geographical areas have shown that there are variations in the prevalence of dupA and its association with H. pylori clinical outcomes. Our group did not observe associations between the presence of dupA and H. pylori clinical outcomes in Brazil. On the other hand, we observed 2 mutations in the sequence of dupA that lead to stop codons: a deletion of an adenine at position 1311 and an insertion of an adenine at position 1426 of the gene. Our aim was to evaluate associations of the presence of dupA with duodenal ulcer and gastric cancer, considering dupA-positive only those H. pylori strains that do not have the mutations in the gene sequence. We also evaluated the effect of infection with a strain carrying an intact dupA on the gastric mucosa histology and IL-8 gastric levels. Colonization with strains that had the intact dupA was negatively associated with gastric carcinoma (p=0.001, OR=0.32, 95% CI=0.16-0.66). The presence of dupA was also associated with an increased degree of antral mucosa inflammation (p=0.01) and with decreased corpus atrophy (p<0.01) as well as with increased gastric mucosa IL-8 levels (p=0.04). In conclusion, the infection with a H. pylori strain containing the dupA without the stop codon polymorphisms is associated with a lower risk of development of gastric carcinoma in Brazilian subjects.
幽门螺杆菌的 dupA 被认为是与十二指肠溃疡病发展相关的一种毒力标志。然而，在不同地理区域进行的研究表明，dupA 的流行率及其与 H. pylori 临床结果的关联存在差异。我们的研究小组在巴西没有观察到 dupA 的存在与 H. pylori 临床结果之间的关联。另一方面，我们观察到 dupA 序列中存在 2 个导致终止密码子的突变：基因 1311 位的腺嘌呤缺失和 1426 位的腺嘌呤插入。我们的目的是评估 dupA 的存在与十二指肠溃疡和胃癌之间的关联，仅考虑那些基因序列中没有突变的 dupA 阳性 H. pylori 菌株。我们还评估了携带完整 dupA 的菌株感染对胃黏膜组织学和 IL-8 胃水平的影响。携带完整 dupA 的菌株定植与胃癌呈负相关（p=0.001，OR=0.32，95%CI=0.16-0.66）。dupA 的存在还与胃窦黏膜炎症程度增加（p=0.01）和胃体萎缩减少（p<0.01）以及胃黏膜 IL-8 水平升高（p=0.04）相关。结论：在巴西人群中，感染含有无终止密码子多态性的 dupA 的 H. pylori 菌株与胃癌发生风险降低相关。
