Nursing mice pass on common antimicrobial

In mouse studies, researchers from the University of California San Diego School of Medicine report that nursing mothers expose their feeding pups to triclosan, an antimicrobial agent commonly used in consumer products, resulting in early signs of liver damage that can eventually lead to more severe impairments. and disease. , such as non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH).

The findings published in the July 27, 2022 online issue of nature communication.

NAFLD is the most common chronic liver disease in the United States, affecting an estimated 100 million adults. It occurs when fat builds up in liver cells due to causes other than excessive alcohol consumption, impairing organ function. The exact cause is unknown, but diet and genetics play an important role. Up to 50 percent of obese people are believed to have NAFLD.

About 20 percent of individuals with NAFLD progress to NASH, a more advanced form of the disease characterized by progressively severe inflammation and organ damage that can lead to liver scarring, cirrhosis, and cancer.

According to a study published by scientists at UC San Diego in June 2022, NASH is the fastest growing cause of liver cancer deaths worldwide, especially in America. It is driven by rapidly rising obesity rates. The prevalence of obesity in the US in 2017 was 42.4 percent, according to the Centers for Disease Control, up from 30.5 percent in 2000.

The prevalence of NAFLD in children is increasing, along with obesity in young people. It is estimated that 9.6 percent of children ages 2 to 19 have NAFLD. A recent study by UC San Diego scientists found that NAFLD in children increases the risk of developing type 2 diabetes later in life.

Triclosan is an ingredient added to various consumer products to reduce or prevent microbial contamination, including soaps, toothpaste, cosmetics, clothing, furniture, kitchenware, pesticides and toys.

“Triclosan is a broad-spectrum antimicrobial agent used in many personal care products and impregnated into a wide variety of materials, from clothing to food packaging. It has been linked to multiple adverse health effects,” said the study’s corresponding author, Robert H. Tukey, PhD, professor in the Department of Pharmacology at the UC San Diego School of Medicine.

In 2016, fueled by mounting evidence and public health concerns, the U.S. Food and Drug Administration banned the use of triclosan in some products and required pre-market approval for others. It remains an ingredient in many products.

Two years ago, Tukey, co-author Michael Karin, PhD, Distinguished Professor of Pharmacology and Pathology at the UC San Diego School of Medicine, and colleagues published evidence that exposure to triclosan exacerbated fatty liver in mice fed a high-fat diet. The latest research builds on how that happens, showing that triclosan is passed from nursing mothers to puppies, who develop early signs of fatty liver and may be more likely to develop fatty liver later in life.

The researchers exposed pregnant females to triclosan in their diets and found that it was efficiently transferred by lactation to newborn mice, causing significant fatty liver during the lactation period, and resulting in hepatosteatosis, triglyceride accumulation, endoplasmic reticulum stress, signs of inflammation and liver fibrosis. Two major metabolic regulators responsible for triclosan-induced fatty liver have been identified.

“Early exposure to triclosan appears to cause pathologies similar to NAFLD and NASH: toxic-associated fatty liver and toxic-associated fatty liver, which may predispose the development of pediatric NAFLD and NASH,” Tukey said. “Recent increases in NAFLD in children may be a result of mother-to-child transmission of environmental toxins such as triclosan.”

Co-authors include: Andre A. Weber, Xiaojing Yang, Elvira Mennillo, Jeffrey Ding, Jeramie D. Watous, Mohit Jain, and Shujuan Chen, all from UC San Diego.

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