 "How daily microplastics exposure may be hardening arteries, mostly in men")
New research suggests that regular exposure to microplastics from everyday sources such as food packaging, clothing and other plastic products may accelerate atherosclerosis, a disease in which arteries narrow and clog, raising the risk of heart attacks and strokes. The effect was seen primarily in males, indicating that biological sex may influence how microplastics affect cardiovascular health.
The study, titled Microplastic exposure elicits sex-specific atherosclerosis development in lean low-density lipoprotein receptor-deficient mice, published in Environment International, found that microplastics significantly worsened artery damage in male mice even when they were lean and had normal cholesterol levels. Female mice did not show the same effect.
The findings add to growing evidence that microplastics are not just environmental contaminants but may directly harm the cardiovascular system, raising concerns about what long-term exposure could mean for human heart health.
What are microplastics, and where do they come from?
Microplastics are tiny plastic particles, often smaller than a grain of rice, that form as larger plastic items break down. They originate from food packaging, plastic bottles, synthetic clothing, tyres, personal care products and even household dust.
Over the past decade, researchers have detected microplastics in drinking water, seafood, salt and air. More alarmingly, they have also been found inside the human body, including in blood, lungs, the placenta and, increasingly, in blood vessels.
How is heart disease linked to microplastics?
Heart disease often begins with atherosclerosis, a slow build-up of fatty plaques inside blood vessels that can eventually block blood flow or rupture, triggering heart attacks or strokes.
Recent human studies have reported microplastics embedded inside atherosclerotic plaques and found that people with higher levels of these particles face a greater risk of cardiovascular events. Until now, however, it was unclear whether microplastics actively cause this damage or simply accumulate in already diseased arteries.
To test whether microplastics can directly worsen atherosclerosis, and whether males and females respond differently, researchers used a well-established animal model of heart disease. They studied mice lacking the low-density lipoprotein receptor (LDL-R), which makes them prone to plaque formation. Crucially, the mice were lean and fed a low-fat, low-cholesterol diet, allowing scientists to isolate the effects of microplastics without confounding factors such as obesity or high cholesterol.
How were the mice exposed to microplastics?
For nine weeks, both male and female mice were given a daily oral dose of microplastics at levels considered environmentally relevant and comparable to what humans may ingest through contaminated food and water.
Researchers then examined the animals’ arteries, blood lipid levels and body weight, and analysed how cells within blood vessels responded to the exposure.
They found that male mice exposed to microplastics developed significantly more severe atherosclerosis than unexposed males. Plaque build-up increased by 63 per cent in the aortic root and by more than six-fold in another major artery branching from the heart.
Female mice exposed to the same amount of microplastics under identical conditions did not show a significant increase in plaque formation.
Importantly, microplastics did not cause weight gain or raise cholesterol levels in either sex, indicating that the artery damage occurred independently of traditional heart disease risk factors.
Do microplastics actually enter blood vessels?
The researchers say they do. In this study, fluorescently labelled microplastics were seen lodged inside artery walls and within atherosclerotic plaques themselves.
This supports growing human evidence that microplastics do not merely circulate briefly in the bloodstream but can embed in blood vessels, where they may directly interfere with normal vascular function.
How do microplastics damage arteries at the cellular level?
Using advanced single-cell RNA sequencing, the study examined how individual cells in artery walls behaved after microplastic exposure. The most affected were endothelial cells, which form the delicate inner lining of blood vessels and regulate blood flow, inflammation and clotting.
Microplastics disrupted normal endothelial function and activated genes known to promote inflammation and plaque formation. In laboratory experiments, similar harmful genetic responses were observed in both mouse and human endothelial cells exposed to microplastics, suggesting a shared biological mechanism.
Why were only males affected in this study?
Scientists suspect that sex hormones, particularly oestrogen, may offer some protection against microplastic-induced vascular damage in females. However, the researchers caution that more studies are needed to fully understand these sex-specific differences.
Can people reduce their exposure to microplastics?
Completely avoiding microplastics is nearly impossible, but exposure may be reduced. Scientists advise limiting the use of plastic food and water containers, cutting down on single-use plastics, avoiding heavily processed foods and supporting broader efforts to reduce plastic pollution.
Medical experts say that until more is known about how microplastics affect the heart, maintaining overall cardiovascular health through a balanced diet, regular exercise and managing known risk factors remains essential. For more health updates, follow #HealthWithBS
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