A new study has found that phthalate -- a chemical used to make plastics more durable -- has led to increased plasma cholesterol levels.
The findings of the study were published in the journal 'Environmental Health Perspectives'.
"We found dicyclohexyl phthalate, or DCHP, strongly binds to a receptor called pregnane X receptor, or PXR," said Changcheng Zhou, who is a professor in the UCR School of Medicine.
"DCHP 'turns on' PXR in the gut, inducing the expression of key proteins required for cholesterol absorption and transport. Our experiments show that DCHP elicits high cholesterol by targeting intestinal PXR signalling," added Zhou.
DCHP, a widely used phthalate plasticizer, has recently been proposed by the Environmental Protection Agency as a high-priority substance for risk evaluation. Not much is known yet about DCHP's adverse effects on humans.
"To our knowledge, our study is the first to show the effects of DCHP exposure on high cholesterol and cardiovascular disease risk in mouse models. Our results provide insights and new understandings of the impact of plastic-associated chemicals on high cholesterol -- or dyslipidemia -- and cardiovascular disease risk," Zhou said.
Zhou's team also found that mice exposed to DCHP had in their intestines higher circulating "ceramides" -- a class of waxy lipid molecules associated with increased cardiovascular disease risk in humans -- in a way that was PXR-dependent.
"This, too, points to the potentially important role of PXR in contributing to the harmful effects of plastic-associated chemicals on cardiovascular health in humans," 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.