Human and Helicobacter pylori coevolution shapes the risk of gastric disease

Abstract

Significance Theory predicts that chronic pathogens with vertical or familial transmission should become less virulent over time because of coevolution. Although transmitted in this way, Helicobacter pylori is the major causative agent of gastric cancer. In two distinct Colombian populations with similar levels of H. pylori infection but different incidences of gastric cancer, we examined human and pathogen ancestry in matched samples to assess whether their genomic variation affects the severity of premalignant lesions. Interaction between human Amerindian ancestry and H. pylori African ancestry accounted for the geographic disparity in clinical presentation. We conclude that coevolutionary relationships are important determinants of gastric disease risk and that the historical colonization of the Americas continues to influence health in modern American populations.

Genotipificación de los factores de virulencia vacA y cagA de Helicobacter pylori en individuos de dos regiones de Colombia con riesgo opuesto de cáncer gástrico

“…En un estudio reciente realizado en Túquerres, zona montañosa de alto riesgo al sur de Colombia, y en Tumaco, población de la costa pacífica con bajo riesgo de cáncer gástrico, Kodaman, et al, (21) reportaron que en los aislamientos de H. pylori de la zona de bajo riesgo predominó el ancestro africano, mientras que en los de la zona de alto riesgo predominó el ancestro europeo. Por otro lado, se observó el predominio del ancestro africano en los individuos infectados de la costa y del ancestro amerindio en los individuos infectados de la zona de montaña.…”

Rapid evolution of distinct Helicobacter pylori subpopulations in the Americas

“…In extreme cases, human migrations that have little or no effect on human ancestry might precipitate substantial changes in H. pylori populations. For example, hspAmerind strains are rare even in populations with substantial Native American ancestry [2]. This suggests that after more than .…”

“…and Native Americans carry genetically distinct populations of bacteria; named hpEurope, hpAfrica1 and hpAfrica2, and hspAmerind, respectively [2]. The relationships between bacterial populations reflect differentiation that has arisen during the complex migration history of humans, with the prefix "hp" indicating a population and "hsp" indicates a subpopulation, which are genetically distinct from each other but less differentiated than populations.…”

“…Several studies have been performed comparing H. pylori ancestry in high-and low risk areas and have linked phylogeographic origin of the bacteria, as well as discordant origin of bacteria and host, to increased risk of gastric cancer development [2,7]. However, these studies have been performed using MLST analysis that, being based only on seven housekeeping genes, is limited in its resolution compared to whole-genome comparisons.…”

“…http://dx.doi.org/10.1101/069070 doi: bioRxiv preprint first posted online Aug. 11, 2016; hspEuropeColombia and hspAfrica1Nicaragua populations have elevated hspAfrica1SAfrica proportions, consistent with recent genetic mixture (Figure 2A). (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) …”