Study Links Oral Bacteria to Chronic Liver Disease Risk

Research from the Technical University of Munich indicates that bacteria found in the mouth may play a crucial role in predicting the risk of chronic liver disease. The study, published in the journal Nature Microbiology, reveals significant connections between oral health and liver conditions, potentially opening new avenues for preventive treatment.

Each year, over two million individuals die from advanced chronic liver disease (ACLD). The study examined the bacterial populations present in saliva and stool samples from 86 patients at various stages of liver disease. The findings demonstrate that both the gut and oral microbiomes exhibit notable changes as liver disease progresses, with alterations to the oral microbiome detectable even at early stages of the condition.

In healthy individuals, bacterial communities in different body sites show substantial differences. However, the research reveals that in patients diagnosed with liver disease, the oral and gut microbiomes become increasingly similar over time. Nearly identical bacterial strains were identified in both the mouths and intestines of these patients.

Melanie Schirmer, Professor of Translational Microbiome Data Integration at TUM, noted, “These strains are typically found in the mouth and are rarely present in the healthy gut. However, we observed increases in the absolute abundances of these oral bacteria in patients with advanced chronic liver disease.” This observation strongly suggests that these bacteria can migrate from the mouth and colonize the gut, a process that may contribute to worsening liver condition.

The research team identified several oral bacterial species that were found in the guts of patients. They also discovered that higher levels of these bacteria in stool samples correlated with damage to the intestinal barrier. Genetic analysis revealed that these bacteria possess genes responsible for producing collagen-degradation enzymes. The presence of these enzymes was confirmed through testing isolated bacteria from stool samples.

Aurelie Cenier, a doctoral researcher and co-first author of the study, explained, “Collagen breakdown can compromise the gut barrier, potentially allowing bacteria and bacterial products to reach other organs, such as the liver. We believe this may worsen the disease.”

The implications of these findings could be significant for future treatment strategies. According to Dr. Vishal Patel from King’s College London, “Our findings open potential new therapeutic strategies for people with advanced chronic liver disease. Protecting or restoring the gut barrier could help slow disease progression. Targeting the oral microbiome offers a way to positively influence the course of the disease and prevent clinical complications.”

As research continues, the links between oral health and chronic liver disease may lead to more effective preventative measures, highlighting the importance of maintaining a healthy microbiome across the body. These insights underscore the need for further studies to explore the therapeutic potential of modulating the oral microbiome in patients at risk of liver disease.