Study Reveals Bacteria Live in the Esophagus
According to a new study by NYU School of Medicine scientists that is contrary to the general belief that the esophagus is free of bacteria According to the researchers of this study, the esophagus is not merely a tube for food traveling from the mouth to the stomach. It also provides an environment for bacteria to live. Martin J. Blaser, Frederick King Professor and chair of the Department of Medicine, and professor of microbiology, and author of the study explains that on a general basis, people usually thought that the esophagus was not hospitable to bacteria. Bacteria were previously believed to move through the esophagus as food borne passengers en route to the stomach.. The esophagus is the tube connecting the mouth to the stomach. But the new study demonstrates that bacteria do indeed live in the esophagus, and these microbes are a diverse bunch. Zhiheng Pei, assistant professor of pathology and medicine, and the studies lead author explains in the article that this study provides evidence for the first time that there are indigenous microbes in the human esophagus. The study was published in the March 23 print issue of the Proceedings of the National Academy of Sciences.
They believe that the findings may have profound implications for treating diseases of the esophagus. The diseases they refer to include gastro esophageal reflux disease or the GERD disease. This type of esophageal disease is known to afflict some 10 million people in the United States. According to the article, chronic inflammation associated with GERD can lead to the development of a precancerous condition called Barretts esophagus. The researchers further add that if the disease causing bacteria are ever found in the esophagus, it may one day be possible to treat these diseases with antibiotics.
The NYU researchers had suspected that the food tube harbored microorganisms, even though the idea of bacteria in the esophagus is new to most people.
Tt is explained that for many years, doctors did not believe that bacteria could survive in the acid environment of the stomach. However, in the early years of the 1980s, researchers discovered that the bacterium Helicobacter pylori lived in the stomach and is associated with ulcerative diseases, like duodenal and gastric ulcers. Antibiotics are now routinely used to treat ulcers. In subsequent years, Blaser and other scientists established the bacterium’s link to certain kinds of stomach cancers.
The connection between H. pylori bacteria and gastric cancer was one of the reasons why the NYU researchers were drawn to the esophagus. The researchers thought of the possibility that there might be certain kinds of disease causing bacteria also reside in the esophagus. Researchers explain that while bacteria have long been known to inhabit the mouth, the evidence that bacteria even lived in the esophagus was inconclusive. Previous studies of the esophagus did not consistently find bacteria in the esophagus that could be cultured. Textbooks also have never described microbes in the esophagus. However, rather than relying on the conventional methods of culturing bacteria in petri dishes in the laboratory, the researchers decided to mine DNA libraries that have been compiled of bacterial genes. The researchers of this study used a technique called PCR or polymerase chain reaction. They used this technique to greatly amplify snippets of DNA extracted from biopsies of tissue from the esophagus. They ten compared the sequences of the DNA in the biopsies to known bacterial DNA.
The biopsies were taken from four patients who each had a healthy esophagus. The biopsies were taken from the distal esophagus. It is specifically the part closest to the stomach. This area, according to the researchers, is especially vulnerable to injury due to the backwash of gastric contents that occurs as a consequence of GERD disease.
The researchers found 95 species of bacteria. The research team estimated that they were able to sample 56 to 79 percent of the species in the biopsies. Therefore, they concluded that even more species may be present. They revealed that many of these bacteria resemble garden-variety microorganisms that are not known to cause disease.
It revealed that more than 60 percent of the esophageal bacteria were shared among all four individuals. This finding indicates that populations of certain bacterial species appear to be common to all people. Pei explains that although many of the bacteria in the esophagus were highly related to the bacteria found in the mouth, certain bacteria were not known residents of the mouth. He further adds that this finding suggests that some, if not all, esophageal bacteria may be unique.
Pei also directly viewed bacteria colonizing the surface of the esophagus according to the article. According to Pei, this proves that the bacteria were not simply traveling through the tube but had taken up residence in the tissue lining it.
According to the National Cancer Institute, which sponsored the NYU study, esophageal adenocarcinoma, a kind of cancer, has been increasing rapidly in white men. Pei adds that animal studies suggest that inflammation and normal bacteria work in concert to cause colon cancer. He explains that esophageal cancer arises in an area of the esophagus where chronic inflammation is occurring.
In the next phase of the researchers work, they plan to identify the bacteria in the esophagus in people who have GERD and other esophageal conditions. They suspect that they may find different bacteria in the samples of unhealthy esophageal tissue. They believe that this could suggest that microorganisms are playing a role.
Blaser explains that the research team are operating in the framework of the microbiome. He explains that this means that microbes are part of us, and part of our identity. He believes that they are, in essence, metabolic and physiologic compartments of the human body.Read more
