Appears to be worse in men
By University of California
- Riverside
“Our findings fit into a broader pattern seen in
cardiovascular research, where males and females often respond differently,”
said lead researcher Changcheng Zhou, a professor of biomedical sciences in the
UCR School of Medicine. “Although the precise mechanism isn’t yet known,
factors like sex chromosomes and hormones, particularly the protective effects
of estrogen, may play a role.”
Microplastics Found Throughout the Body and Environment
Microplastics have become nearly impossible to avoid. They
are present in food, drinking water, and the air, and have even been detected
inside the human body. Recent studies involving people have found microplastics
embedded in atherosclerotic plaques and have linked higher concentrations to an
increased risk of cardiovascular disease. Until now, however, it was
unclear whether these particles actively damage arteries or simply accompany
disease.
“It’s nearly impossible to avoid microplastics completely,”
Zhou said. “Still, the best strategy is to reduce exposure by limiting plastic
use in food and water containers, reducing single-use plastics, and avoiding
highly-processed foods. There are currently no effective ways to remove
microplastics from the body, so minimizing exposure and maintaining overall
cardiovascular health — through diet, exercise, and managing risk factors —
remains essential.”
How the Mouse Study Was Designed
In a study published in Environment International, Zhou and his colleagues used a widely accepted animal model for heart disease research. The team studied LDLR-deficient mice, which are genetically prone to developing atherosclerosis. Both male and female mice were fed a low-fat, low-cholesterol diet comparable to what a lean and healthy person might consume.
Over a nine-week period, the mice received daily doses of
microplastics (10 milligrams per kilogram of body weight). These exposure
levels were chosen to reflect amounts considered environmentally relevant and
similar to what humans could encounter through contaminated food and water.
Severe Plaque Buildup Seen Only in Males
The results showed a striking difference between sexes. In
male mice, microplastic exposure greatly accelerated atherosclerosis. Plaque
buildup increased by 63% in the aortic root, the portion of the aorta connected
to the heart, and by 624% in the brachiocephalic artery, which branches from
the aorta in the upper chest. Female mice exposed to the same conditions did
not experience a significant increase in plaque formation.
Importantly, the microplastics did not cause the mice to
gain weight or raise their cholesterol levels. The animals remained lean, and
their blood lipid measurements stayed the same, indicating that the artery
damage was not driven by classic risk factors such as obesity or high
cholesterol.
Microplastics Disrupt Cells That Protect Blood Vessels
The researchers also discovered that microplastics interfered with the cells lining the arteries. Using single-cell RNA sequencing, a method that reveals which genes are active in individual cells, the team found changes in both the behavior and balance of several cell types involved in atherosclerosis. Endothelial cells — which form the inner lining of blood vessels and help control inflammation and blood flow — were affected most strongly.
“We found endothelial cells were the most affected by
microplastic exposure,” Zhou said. “Since endothelial cells are the first to
encounter circulating microplastics, their dysfunction can initiate
inflammation and plaque formation.”
Particles Found Inside Plaques and Triggering Harmful
Genes
In laboratory experiments, fluorescent microplastics were
seen entering atherosclerotic plaques and accumulating within the endothelial
layer. These findings align with recent human studies that have also identified
microplastics inside arterial lesions.
The team further reported that microplastics activated
damaging gene activity in endothelial cells taken from both mice and humans.
Exposure triggered pro-atherogenic (plaque-promoting) genes in
both species, suggesting a shared biological response to microplastic
exposure.
“Our study provides some of the strongest evidence so far
that microplastics may directly contribute to cardiovascular disease, not just
correlate with it,” Zhou said. “The surprising sex-specific effect — harming
males but not females — could help researchers uncover protective factors or
mechanisms that differ between men and women.”
Why Males Are More Vulnerable and What Comes Next
Zhou and his colleagues note that additional research is
needed to understand why males appear more susceptible to microplastic-related
artery damage. The team plans to explore whether similar effects occur in
people.
“We would like to investigate how different types or sizes
of microplastics affect vascular cells,” Zhou said. “We will also look into the
molecular mechanisms behind endothelial dysfunction and explore how
microplastics affect male and female arteries differently. As microplastic
pollution continues to rise worldwide, understanding its impacts on human
health — including heart disease — is becoming more urgent than ever.”
Reference: “Microplastic exposure elicits sex-specific
atherosclerosis development in lean low-density lipoprotein receptor-deficient
mice” by Ting-An Lin, Jianfei Pan, Mya Nguyen, Qianyi Ma, Liang Sun, Sijie
Tang, Matthew J. Campen, Hong Chen and Changcheng Zhou, 17 November 2025, Environment
International.
DOI:
10.1016/j.envint.2025.109938
Zhou was joined in the study by colleagues at UCR, Boston
Children’s Hospital and Harvard Medical School in Massachusetts, and the
University of New Mexico Health Sciences.
The study was partially supported by grants from
the National Institutes of Health.
