Division of Gastroenterology, Hepatology, and Nutrition, Vanderbilt University School of Medicine, MRBIV, Room 1030C, 2215 Garland Avenue, Nashville, TN 37232, USA.
Gut. 2011 Sep;60(9):1189-95. doi: 10.1136/gut.2010.234468. Epub 2011 Feb 25.
Helicobacter pylori colonises the stomach in half of all humans, and is the principal cause of gastric cancer, the second leading cause of cancer death worldwide. While gastric cancer rates correlate with H pylori prevalence in some areas, there are regions where infection is nearly universal, but rates of gastric cancer are low. In the case of Colombia, there is a 25-fold increase in gastric cancer rate in the Andean mountain (high risk) region compared to the coastal (low risk) region, despite similarly high (∼90%) prevalence of H pylori in the two locations. Our aim was to investigate the ancestral origin of H pylori strains isolated from subjects in these high- and low-risk regions and to determine whether this is a predictive determinant of precancerous lesions.
Multi-locus sequence typing was used to investigate phylogeographic origins of infecting H pylori strains isolated from subjects in the Pacific coast and Andes Mountains in the state of Nariño, Colombia. We analysed 64 subjects infected with cagA+ vacA s1m1 strains. Gastric biopsy slides from each individual were scored for histological lesions and evaluated for DNA damage by immunohistochemistry.
We show that strains from the high-risk region were all of European phylogeographic origin, whereas those from the low risk region were of either European (34%) or African origin (66%). European strain origin was strongly predictive of increased premalignant histological lesions and epithelial DNA damage, even in the low-risk region; African strain origin was associated with reduced severity of these parameters.
The phylogeographic origin of H pylori strains provides an explanation for geographic differences in cancer risk deriving from this infection.
幽门螺杆菌在全球半数人群的胃中定植，是导致胃癌的主要原因，也是全球癌症死亡的第二大主要原因。尽管在某些地区，胃癌的发病率与 H pylori 的流行程度相关，但也有一些地区的感染率几乎普遍存在，但胃癌的发病率却很低。以哥伦比亚为例，安第斯山脉（高危）地区的胃癌发病率是沿海地区（低危）的 25 倍，尽管这两个地区 H pylori 的流行率（约 90%）相似。我们的目的是研究从高、低风险地区的人群中分离出的 H pylori 菌株的祖先起源，并确定这是否是癌前病变的预测性决定因素。
使用多位点序列分型（Multi-locus sequence typing）方法来研究哥伦比亚纳里尼奥州太平洋海岸和安第斯山脉地区感染 H pylori 菌株的地理起源。我们分析了 64 名感染 cagA+ vacA s1m1 菌株的个体。对每位个体的胃活检切片进行组织学病变评分，并通过免疫组织化学法评估 DNA 损伤。
我们表明，高危地区的菌株均来自欧洲的地理起源，而低危地区的菌株则来自欧洲（34%）或非洲（66%）。欧洲菌株的起源与增加的癌前组织学病变和上皮细胞 DNA 损伤密切相关，即使在低危地区也是如此；非洲菌株的起源与这些参数的严重程度降低有关。
H pylori 菌株的地理起源为这种感染导致的癌症风险的地理差异提供了解释。
