Plastic is now ubiquitous, with tiny fragments found in several major organs of the human body, including the placenta.
Considering how easily tiny particles can penetrate our tissues, it is important that we understand exactly the risks they may pose to our health.
Researchers have been busy studying the effects of microplastics in organ mini-replicas and mice to understand how they might affect the human body. However, the concentrations of microplastics used in these studies may not reflect people's exposure in the real world, and few studies have been conducted on humans.
Now, a small study in Italy has found that microplastic fragments in fat deposits were surgically removed from patients who underwent surgery to block arteries and reported their health outcomes nearly 3 years later.
Removing fatty plaque from a narrowed artery with carotid endarterectomy can reduce the risk of future strokes.
The team behind the new study, led by Raffaele Marfella, a medical researcher at the University of Campania in Naples, wanted to know how the risk of stroke and heart attack and death compares between patients with and those who do not have microplastics in the plaque.
The researchers followed 257 patients for 34 months and found that nearly 60 percent of them had measurable amounts of polyethylene in plaques extracted from fatty thickened arteries, and 12 percent also had polyvinyl chloride (PVC) in the fat deposits extracted.
Polyvinyl chloride is available in both rigid and flexible forms and is used to make water pipes, plastic bottles, flooring, and packaging. Polyethylene is the most common plastic and is also used in plastic bags, films, and bottles.
Because of the previously discovered microplastics flowing through people's bloodstream, the researchers have legitimate concerns about heart health. Laboratory studies have shown that microplastics trigger inflammation and oxidative stress in heart cells, impair heart function, alter heart rate, and cause heart scarring in animals such as mice.
Marfella and colleagues wrote: "Observational data from occupational exposure studies also suggest that people exposed to plastic-related pollution, including polyvinyl chloride, have an increased risk of cardiovascular disease compared to the general population. ”。
In this study, patients with microplastics in the removed plaque were twice as likely to have a stroke, a non-fatal heart attack, or die from any cause after 34 months than those who had no microplastics detected in the plaque removed by the surgeon.
The number of microplastics, and even smaller particles called nanoplastics, was measured using a technique called pyrolysis-gas chromatography-mass spectrometry, and their presence was confirmed using another method – stable isotope analysis – that distinguishes between carbon in human tissues and carbon in plastics made from petrochemicals.
Microplastics can also be seen under a powerful microscope: the researchers observed fragments of plastic with jagged edges inside immune cells called macrophages and inside fatty plaques. By examining tissue samples, the team also found that patients with microplastics in the plaques had higher levels of inflammatory markers in their bodies.
In a tissue section viewed under a microscope, two black-and-white images show jagged plastic particles, marked with arrows.
Jagged plastic particles are seen inside macrophages, removing fatty tissue deposits from blocked arteries. (Marfella et al., New England Journal of Medicine, 2024).
However, keep in mind that observational studies like this do not definitively conclude that microplastics cause downstream cardiac effects; It's just that there's a connection. This study did not take into account other risk factors for cardiovascular disease, such as smoking, inactivity, and air pollution.
Philip J., a pediatrician, public health physician, and epidemiologist at Boston College"Although we don't know what other exposures in this study may have contributed to adverse outcomes for patients, the discovery of microplastics and nanoplastics in plaque tissue is a breakthrough discovery in itself that raises a series of pressing questions," Landrigan wrote, "such as how to reduce exposure, in the accompanying editorial."
Plastic production has grown over the past two decades, with only a small fraction of it being produced, but the incidence of cardiovascular disease has been declining in some parts of the world, so more research is needed to understand the link between the two.