A team of researchers from the University of California San Diego School of Medicine has found evidence that triclosan ( an antimicrobial found in many soaps and other household items) worsens fatty liver disease in mice.
The study appeared in Proceedings of the National Academy of Sciences on November 23, 2020. This paper outlines the molecular mechanisms by which triclosan play havoc with metabolism and the gut microbiome. The study also describes how triclosan removes the natural protection of liver cells.
Triclosan is an antibacterial and antifungal agent present in some consumer products, including toothpaste, soaps, detergents, toys, and surgical cleaning treatments. The chemical name of triclosan is 5-chloro-2-(2,4-dichlorophenoxy)phenol and its formula is C12H7Cl3O2
“Triclosan’s increasingly broad use in consumer products presents a risk of liver toxicity for humans,” said Robert H. Tukey, PhD, a professor in the Department of Pharmacology at UC San Diego School of Medicine. “Our study shows that common factors that we encounter in every-day life — the ubiquitous presence of triclosan, together with the prevalence of high consumption of dietary fat — constitute a good recipe for the development of fatty liver disease in mice.”
In the current research, the team fed a high-fat diet to mice with type 1 diabetes. This high-fat diet led to non-alcoholic fatty liver disease (NAFLD).
These mice were divided into two groups wherein one group was fed with triclosan and fat diet whereas other group was fed only with fat diet. In the mice with triclosan, the development of fatty liver and fibrosis was accelerated.
The following is what is likely to happen according to the study: Eating a high-fat diet tells cells to produce more fibroblast growth factor 21, which helps protects liver cells from damage. The research team discovered that triclosan messes with two molecules, ATF4 and PPARgamma, which cells need to make the protective growth factor. The antimicrobial also messed with genes involved in metabolism. In addition, the mice exposed to triclosan had fewer types of bacteria living in the intestines, and makeup similar to that seen in patients with NAFLD. Less gut microbiome diversity is generally associated with poorer health.
Since these same molecular systems also operate in humans, this new information will help researchers better understand NAFLD, and give them a new place to start in designing potential interventions to prevent and mitigate the condition.
“This underlying mechanism now gives us a basis on which to develop potential therapies for toxicant-associated NAFLD,” said Tukey.
Mei-Fei Yueh, Feng He, Chen Chen, Catherine Vu, Anupriya Tripathi, Rob Knight, Michael Karin, Shujuan Chen, Robert H. Tukey. Triclosan leads to dysregulation of the metabolic regulator FGF21 exacerbating high fat diet-induced nonalcoholic fatty liver disease. Proceedings of the National Academy of Sciences, 2020; 202017129 DOI: 10.1073/pnas.2017129117
Press Release: University of California – San Diego