A specific Streptococcus mutans strain aggravates non-alcoholic fatty liver disease

Area of Science:

• Microbiology
• Hepatology
• Pathogenesis

Background:

• Streptococcus mutans is a primary cause of dental caries.
• S. mutans has been linked to systemic conditions like cerebral hemorrhage and inflammatory bowel disease.

Purpose of the Study:

• To investigate the potential role of S. mutans in the development of non-alcoholic steatohepatitis (NASH).
• To evaluate the impact of different S. mutans strains on liver health in a mouse model.

Main Methods:

• C57BL/6J mice were fed a high-fat diet for 4 weeks.
• Mice received intravenous administration of S. mutans strains (oral MT8148 or blood isolate TW871) or phosphate-buffered saline.
• Liver and body weights were measured, and liver tissues were analyzed histopathologically at 8 and 12 weeks post-infection.

Main Results:

• Mice infected with the TW871 S. mutans strain exhibited significantly increased body and liver weights compared to controls.
• Histopathology revealed inflammatory cell infiltration and adipocellular deposition in the liver 8 weeks post-TW871 infection.
• Liver fibrosis was evident 12 weeks after infection with the TW871 strain.

Conclusions:

• A specific strain of S. mutans (TW871) has the potential to induce non-alcoholic steatohepatitis in mice.
• These findings suggest a novel pathway linking oral bacteria to liver pathology.