Toxic gut bacteria make alcohol-triggered liver disease more deadly
ScienceMag 11/13/19
For a heavy drinker whose liver has been destroyed by alcohol, an organ transplant is often the only realistic option. But because of donor liver shortages and rules that withhold them from people who have not shed their alcohol addiction, many go without. Tens of thousands die from alcoholic liver disease each year in the United States—and some go downhill much faster than others. Now, scientists have found a reason for this disparity: a toxin produced by some strains of a common gut bacterium. Working in mice, they have also tested a potential therapy, based on bacteria-destroying viruses found lurking in the sewer.
Why some drinkers with liver disease fare much worse than others "has always been a conundrum," says Jasmohan Bajaj, a gastroenterologist and liver specialist at Virginia Commonwealth University in Richmond. The bacterium Enterococcus faecalis offers an explanation, Bernd Schnabl, a gastroenterologist at the University of California, San Diego (UCSD), School of Medicine, and colleagues report this week in Nature. In fecal samples from patients with alcoholic liver disease, levels of it were 2700 times higher than in nondrinkers, although the mere quantity didn't correlate with a person's outcome. Instead, the researchers identified a cell-destroying toxin called cytolysin produced by select strains of E. faecalis as the likely reason that some patients with alcoholic liver disease had severe symptoms.
