Zhiheng Pei
New York University School of Medicine, USA
Title: Microbial association with esophageal adenocarcinoma and reflux disorders.
Biography
Biography: Zhiheng Pei
Abstract
For unclear reasons, the incidence of esophageal adenocarcinoma (EA) arising out of Barrett’s esophagus (BE) and reflux esophagitis (RE) has risen more than 600% in the United States since the 1970s. Although specific host factors might predispose one to disease risk, such a rapid increase in incidence must be predominantly environmental. The widespread use of antibiotics since 1950s could have contributed to this drastic change. Antibiotic exposure prior to 1980s could have unintentionally eradicated Helicobacter pylori which plays a protective role against EA, BE, and RE. Both human and animal studies suggest that exposure to antibiotics changes the colonic microbiome in favour of obesity. Case control studies showed microbiome is altered in the distal esophagus in patients with reflux disorders including EA. The microbiome in esophageal diseases is more diversified than in controls. This effect is not only seen in the esophagus but also observed in the mouth and stomach. Overall, esophageal diseases tend to be associated with depletion of Gram-positive bacteria and enrichment of Gram-negative bacteria. The relative abundance of Streptococcus, the most abundant Gram-positive bacteria in the foregut, tends to decrease along the disease progression from normal to reflux, Barrett’s esophagus, and adenocarcinoma, in both the mouth and esophagus. Microbiome alteration often extended to the mouth and sometimes to the stomach and rectum. The altered microbiome could play a more direct role in the initiation and progression of reflux disorders than H. pylori or obesity by in situ induction of chronic inflammation and/or activation of carcinogens.