Gut microbiome in liver health: 10 recent reports

The gut microbiome has become a focused topic for researchers lately in hepatology and gastroenterology as its effects on gastric and liver health have yet to be fully understood. Recent studies have revealed metabolites and phyla organizations that may increase the risk for certain liver diseases or may protect from conditions such as nonalcoholic fatty liver disease.

The following reports include details on such metabolites as well diet’s role in the gut microbiome and correlating effects on liver health.

Gut microbiome metabolite linked to hepatic steatosis, fibrosis

The microbial metabolite 3-(4-hydroxyphenyl)lactate, linked to multiple bacterial phylum in the gut microbiome, correlated significantly with liver fibrosis and demonstrated a shared gene-effect with hepatic steatosis and fibrosis, according to a recently published study on nonalcoholic fatty liver disease.

“Utilizing a uniquely, well-characterized, discovery cohort of community-dwelling twins and families, and a validation cohort of patients with biopsy-proven NAFLD, we report the association between a novel gut microbiome-derived serum metabolite, 3-(4-hydroxyphenyl) that has a statistically and clinically significant shared gene-effect with both hepatic steatosis and fibrosis,” Cyrielle Caussy, MD, PhD, from the NAFLD Research Center in California, and colleagues wrote. Read more

Surprising number of common medications impact the gut microbiome

A study of more than 1,000 medications spanning all therapeutic classes showed that one in four non-antibiotic drugs inhibited the growth of at least one species of bacteria in the gut microbiome.

Investigators said these findings were unexpected and could help to improve understanding of the efficacy and side effects of existing drugs, and the largely “unnoticed” risk for the promotion of antibiotic resistance by non-antibiotic medications. Read more

High red, processed meat intake increases fatty liver disease, insulin resistance risk

High consumption of red meat and processed meat correlated with an increased risk for nonalcoholic fatty liver disease and insulin resistance, according to recently published data.

Additionally, researchers found that cooking meat with unhealthy methods — including frying and cooking for a long duration — correlated with a higher risk for insulin resistance. Read more

Middle Eastern diet increases gut microbiota diversity, shows benefit in cirrhosis

Diets with a high intake of vegetables, cereals, coffee, tea and fermented milk products like yogurt correlated with a higher diversity in the gut microbiome. In turn, a higher microbial diversity correlated with a lower risk for hospitalization among patients with cirrhosis, according to recently published data.

“We wanted to know why cirrhosis is so much more commonly a cause of death in some countries and why the disparities between populations exist,” Jasmohan S. Bajaj, MD, from the Virginia Commonwealth University, told Healio Gastroenterology and Liver Disease. “Specifically in the United States, cirrhosis as a cause of death is quite high, whereas it is not as high in some Middle Eastern countries like Turkey. We hypothesized that this could be because of the gut microbes and diet, which are clearly different in patients from these countries.” Read more

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BiomX acquires RondinX to expand microbiome targets for IBD, liver disease

BiomX recently announced the acquisition of RondinX to expand the company’s pipeline with novel microbial targets for the treatment of liver disease and inflammatory bowel disease, according to a press release.

“We’ve seen a lot of value driven by the fact that we can identify such targets. There are two parts to this: one, define the target; and two, take it out,” Jonathan Solomon, CEO of BiomX told Healio Gastroenterology and Liver Disease. “For us, this acquisition makes a lot of sense because RondinX have unique, cutting edge approaches to analyzing the genetics of gut bacteria as well as identifying their growth rate and characteristics. It fits exactly with the technology that we have. Put together, I think we have a true cutting-edge target-discovering agent.” Read more

Whole grain diet reduces body weight, ineffective in gut microbiome

Compared with diets higher in refined grains, whole grain diets did not alter insulin sensitivity or the gut microbiome, according to a recently published study. However, results of the study revealed that diets higher in whole grains reduced body weight and systemic low-grade inflammation.

“Most people will benefit from choosing whole grains instead of refined grains. Generally speaking, wholegrain consumption gives prolonged satiety which over time may result in a lower body weight,” Henrik Munch Roager, from the National Food Institute, Technical University of Denmark, told Healio Gastroenterology and Liver Disease. “Furthermore, consumption of whole grains lowers the concentrations of inflammatory markers in the circulation, possibly due to the beneficial compounds present in whole grains.” Read more

VIDEO: Microbiota composition, functionality normalizes after liver transplant

In this exclusive video from The Liver Meeting 2017, Jasmohan S. Bajaj, MD, from the Virginia Commonwealth University in Richmond, Va., discusses results of a study that assessed the microbiome composition and function after liver transplantation.

“What we do know in patients with cirrhosis is that there’s a lot of dysbiosis, which is changes in the microbiome, which are unfavorable to the body, and these can reverse after liver transplant,” he told Healio Gastroenterology and Liver Disease. “However, what we do not know is whether the functional changes brought by the microbiome and their host microbiota interactions also change hand-in-hand.” Read more

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NAFLD-associated serum metabolites linked to genetics

The discovery of a novel gut serum metabolite with a shared genetic effect with NAFLD sheds light on the pathogenesis of fat in the liver and fibrosis, according to a presentation at The Liver Meeting 2017.

“NAFLD is the common cause of hepatic disease in the United States and worldwide,” Cyrielle Caussy, MD, of the NAFLD Research Center, University of California, San Diego, La Jolla, Calif., and Medicine Lyon at the University of Lyon, in France, said during a press conference. “Previous studies have shown NAFLD is heritable and has a shared genetic effect with hepatic steatosis and fibrosis, but little is known about the mechanism involved in this heritability. We sought to use the profiling of the metabolite to try to identify interesting pathways that could explain the genetic determination that could explain fat in the liver and steatosis in NAFLD.” Read more

Gut microbiome signature may help detect advanced fatty liver

Results of a recently published study revealed preliminary evidence for a fecal-microbiome-derived metagenomic signature to detect advanced fibrosis in patients with nonalcoholic fatty liver disease.

“We found that the gut microbiomes in NAFLD are dominated by members of Firmicutes and Bacteroidetes, followed by Proteobacteria and Actinobacteria in much lower abundances,” Rohit Loomba, MD, MHSc, director of the NAFLD Research Center, UC San Diego Health, and professor of medicine at UC San Diego School of Medicine, and colleagues wrote. “However, as the disease progresses from mild/moderate NAFLD to advanced fibrosis, the Proteobacteria phylum has a statistically significant increase in abundance while the Firmicutes phylum decreases.” Read more

Liver fibrosis linked to blood microbiota in obesity

Blood microbiota dysbiosis and liver fibrosis existed concomitantly in patients with obesity, according to published findings.

“We have shown in an extensively phenotyped cohort, for the first time, a relationship between liver fibrosis in patients with severe obesity and both blood bacterial burden and blood microbiota profile,” Benjamin Lelouvier, PhD, group leader of molecular and cellular biology at Vaiomer SAS in France, told Healio Gastroenterology and Liver Disease. “The 16S rDNA concentration was significantly higher in patients with liver fibrosis whereas the diversity indices were lower for all taxonomic levels considered. We found specific differences in the proportion of specific bacterial taxa in both blood and feces that correlate with the presence of liver fibrosis, thus defining a specific signature of the liver disease.” Read more