Plastics, which are a part of modern life, are useful but can pose a significant challenge to the environment and can also be a health problem. This is because exposure to chemicals associated with plastic, such as the basic chemical bisphenol A and phthalate plasticizers, can increase the risk of human cardiovascular disease. However, the underlying mechanisms behind this remain elusive.
A team led by Changcheng Zhou, a biomedical scientist at the University of California, Riverside, now raises hopes of solving the mystery. In a mouse to study, the researchers found a phthalate – a chemical used to make plastics more durable – caused increased plasma cholesterol levels.
“We have found that dicyclohexyl phthalate, or DCHP, binds strongly to a receptor called pregnane X receptor, or PXR,” said Zhou, professor at UCR. Medicine School. âDCHP ‘activates’ PXR in the gut, inducing the expression of key proteins necessary for the absorption and transport of cholesterol. Our experiments show that DCHP causes elevated cholesterol by targeting intestinal PXR signaling.
DCHP, a widely used phthalate plasticizer, has has recently been proposed by the Environmental Protection Agency as a high priority substance for risk assessment. Not much is yet known about the side effects of DCHP in humans.
âTo our knowledge, our study is the first to show the effects of DCHP exposure on hypercholesterolemia and cardiovascular disease risk in mouse models,â Zhou said. “Our results provide information and new understanding of the impact of chemicals associated with plastic on hypercholesterolemia – or dyslipidemia – and the risk of cardiovascular disease.”
Zhou’s team also found that mice exposed to DCHP had higher circulating “ceramides” in their blood – a class of waxy lipid molecules associated with an increased risk of cardiovascular disease in humans – in a dependent fashion. of the PXR.
âIt also highlights the potentially important role of PXR in contributing to the harmful effects of chemicals associated with plastic on cardiovascular health in humans,â Zhou said.
Zhou was joined in the research by Zhaojie Meng, Jinwei Liu, Rebecca Hernandez and Miko Gonzales of UCR; and Yipeng Sui, Taesik Gwag and Andrew J. Morris of the University of Kentucky. The study was published in Environmental Health Perspectives, a leading journal in the field of environmental health.
The work was supported in part by the National Institute of Environmental Health Sciences, or NIEHS. Hernandez was supported by a recently renewed NIEHS training grant at UCR. Gonzales, an undergraduate student, was a UCR Honors Capstone Fellow.
The research paper is titled “Effects of Dicyclohexyl Phthalate Exposure on PXR Activation and Lipid Homeostasis in Mice”.
Header photo by Nick Fewings to Unsplash.