New research from the University of California, Riverside suggests microplasticsTiny plastic particles — generally under 5 millimeters — released from food packaging, textiles, household plastics, and industrial waste; they are now detected in human food, drinking water, air, and body tissues, including inside arterial plaques. may directly accelerate heart disease — especially in males.
Here’s what the study uncovered, explained as simple Q&A.

Q: What exactly are microplastics?

A: Microplastics are tiny plastic particles released from:

• Food packaging
• Clothing and textiles
• Household plastics
• Industrial waste

They are now found in:

• Food
• Drinking water
• Air
• Human tissues — including inside arteries

Q: Why are scientists worried about microplastics and heart disease?

A: Recent clinical studies found microplastics inside human arterial plaquesA deposit within the artery wall made up of lipids, immune cells, cellular debris, and fibrous tissue that accumulates over time and can narrow or block blood flow; also called an atherosclerotic lesion or atheroma. and linked higher levels to worse cardiovascular outcomes.
But until now, it wasn’t clear whether they directly cause damage.

The new study provides some of the strongest evidence that microplastics can injure vascular cells and accelerate plaquePlaque is the buildup of cholesterol, immune cells, scar tissue, and calcium inside an artery wall. formation.

Q: What did the researchers do in this new study?

A: Scientists used a well-established heart-disease mouse model (LDLR-deficient miceA well-established animal model of atherosclerosis in which the gene encoding the LDL receptor is knocked out, causing cholesterol-rich lipoproteins to accumulate in the blood and accelerate plaque formation; widely used to test how environmental exposures affect cardiovascular disease.) and:

• Fed them a low-fat, low-cholesterol “healthy” diet
• Exposed them to microplastics daily for 9 weeks
• Used doses similar to real-world human exposure
• Compared changes between male and female mice

Q: What did they find?

Major Finding 1 — Microplastics dramatically worsened atherosclerosisAtherosclerosis is the disease behind most heart attacks and many strokes. Cholesterol particles get stuck in the wall of an artery, the body sends immune cells to clean up, and over years that mess hardens into plaque., but only in males.

Male mice exposed to microplastics developed:

• 63% more plaque in the aortic rootThe section of the aorta immediately above the heart where it exits the left ventricle; it is a common site for early atherosclerotic plaque formation and is routinely measured in mouse models of heart disease to quantify plaque burden.
• 624% more plaque in the brachiocephalic arteryA major artery branching from the aortic arch that supplies blood to the head, neck, and right arm; in mouse atherosclerosis studies it is a key site for plaque measurement because it develops lesions rapidly and reproducibly.

Female mice showed no significant plaque increase under the same conditions.

Major Finding 2 — The effect had nothing to do with weight or cholesterolCholesterol is a waxy substance your body needs. It goes into cell walls, hormones, vitamin D, and the bile that digests your food. You would die without it..

Despite severe arteryAn artery is a blood vessel that carries blood away from the heart to the rest of the body. damage:

• No weight gain
• No increase in cholesterol
• No changes in lipid profilesA blood test panel that measures total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides, used to assess cardiovascular risk and monitor the effect of dietary or drug interventions.

This shows microplastics caused direct vascular injury, separate from traditional risk factorsA risk factor is something that raises your chance of developing a disease — high cholesterol particles, high blood pressure, smoking, diabetes, family history..

Major Finding 3 — Microplastics impaired endothelial cellsThe thin layer of cells lining the inner surface of all blood vessels; they regulate vascular tone, prevent clotting, and control the passage of substances into the artery wall — and their dysfunction is an early, critical step in atherosclerosis..

Endothelial cells (the lining of blood vessels) were the most affected:

• Their gene activity shifted in harmful ways
• They triggered inflammationInflammation is your immune system's response to injury or something it treats as an invader. It brings swelling, heat, and cleanup cells.
• They promoted plaque growth
• Microplastics were found inside the plaques themselves

This matches human studies that found microplastics in arterial lesionsIn cardiology, a lesion refers to a discrete area of atherosclerotic plaque narrowing a coronary artery, typically described by the percentage of luminal obstruction it causes. The article describes four residual lesions too small in vessel diameter to accept a stent after the most critical one was treated..

Q: Why were males affected but not females?

Researchers don’t yet know, but they suspect:

• Sex chromosomes
• Hormonal differences
• Estrogen’sEstrogen is a hormone, present at much higher levels in women before menopause, that affects blood vessels, cholesterol, and bone. protective cardiovascular effects

This pattern appears in other heart-disease research as well.

Q: Does this mean microplastics could harm human heart health?

A: The study strongly suggests they can, though more human research is needed.
The biological responses observed in mice also appeared in human endothelial cells in the lab.

Researchers warn that microplastics may be:

“Direct contributors to cardiovascular disease, not just correlations.”

Q: Can we remove microplastics from the body?

A: At this time, no known method exists for removing microplastics once they enter tissues.

Q: How can people reduce their exposure?

Scientists recommend:

• Using fewer plastic food and water containers
• Avoiding single-use plastics
• Reducing highly processed foods
• Using glass or stainless-steel bottles
• Improving indoor air quality (microfibers circulate in dust)
• Maintaining heart health through diet and exercise

Q: What are researchers studying next?

Future work will explore:

• Why males are more vulnerable
• Whether different types of microplastics cause different injuries
• How microplastics interact with vascular cells
• Whether similar sex-specific effects occur in humans

Q: Who conducted the research?

The study involved scientists from:

• University of California, Riverside
• Boston Children’s Hospital
• Harvard Medical School
• University of New Mexico Health Sciences
  Funding came in part from the National Institutes of Health.

References

1. Wright SL, Kelly FJ. Plastic and Human Health: A Micro Issue?. Environ Sci Technol. 2017;51(12):6634-6647. doi:10.1021/acs.est.7b00423
2. Marfella R, Prattichizzo F, Sardu C, et al. Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. N Engl J Med. 2024;390(10):900-910. doi:10.1056/NEJMoa2309822
3. Prata JC, da Costa JP, Lopes I, Duarte AC, Rocha-Santos T. Environmental exposure to microplastics: An overview on possible human health effects. Sci Total Environ. 2020;702:134455. doi:10.1016/j.scitotenv.2019.134455
4. Campanale C, Massarelli C, Savino I, Locaputo V, Uricchio VF. A Detailed Review Study on Potential Effects of Microplastics and Additives of Concern on Human Health. Int J Environ Res Public Health. 2020;17(4):1212. Published 2020 Feb 13. doi:10.3390/ijerph17041212
5. Cox KD, Covernton GA, Davies HL, Dower JF, Juanes F, Dudas SE. Human Consumption of Microplastics. Environ Sci Technol. 2019;53(12):7068-7074. doi:10.1021/acs.est.9b01517