Research Insights

Plastic Particles in Cholesterol Plaques Linked to Poor Outcomes

Plastics, from food packaging to electronic devices, have become integral to our daily lives. However, the alarming rise in plastic pollution has raised concerns about its impact on human health. A recent New England Journal of Medicine study (linked here) has shed light on a potential link between plastics found in cholesterol deposits inside the carotid artery and future cardiovascular events.

 

Study Background

Carotid plaques are deposits of cholesterol, fat, calcium, and other substances that build up inside the carotid arteries, the major blood vessels in the neck that supply blood to the brain, face, and neck (see below figure). Over time, these plaques can narrow the carotid arteries, restricting blood flow to the brain. If a piece of plaque breaks off and travels to the brain, it can block a smaller blood vessel, causing a stroke.

 

Plastic Particles in Cholesterol Plaques Linked to Poor Outcomes Heart Matters

The risk of stroke increases when the carotid arteries become severely narrowed or if a piece of plaque breaks off and causes a blockage in a blood vessel leading to the brain. This can result in a lack of oxygen and nutrients to brain cells, leading to stroke symptoms such as sudden weakness or numbness on one side of the body, difficulty speaking or understanding speech, vision problems, and severe headaches.

 

Carotid endarterectomy

This is a surgical procedure performed to remove plaque buildup from the carotid arteries. It is typically considered for individuals with significant narrowing (stenosis) of the carotid arteries, usually due to atherosclerosis (plaque buildup).

Carotid endarterectomy is considered when:

Symptoms are present: If an individual experiences symptoms of reduced blood flow to the brain, such as transient ischemic attacks (TIAs) or minor strokes, and diagnostic tests reveal significant narrowing of the carotid arteries, carotid endarterectomy may be recommended to reduce the risk of future strokes.

High-grade stenosis: If imaging tests, such as ultrasound or angiography, show that the carotid artery is severely narrowed (usually greater than 70%) and the individual has not experienced symptoms, carotid endarterectomy may still be considered to prevent future strokes. The decision is always personalized and will occur following discussions with yourself, a neurologist, and the vascular surgeon.

Other factors: The decision to undergo carotid endarterectomy may also consider other factors, such as the individual’s overall health, age, risk factors for stroke (such as smoking, high blood pressure, and diabetes), and plaque in other blood vessels while also considering one’s surgical fitness.

Vascular surgeons typically perform carotid endarterectomy. This procedure involves an incision in the neck to access the carotid artery, removing plaque buildup and repairing the artery. 

 

Plastic Particles in Cholesterol Plaques Linked to Poor Outcomes Heart Matters

This illustration depicts a brain with an area of stroke resulting from plaque buildup in the carotid artery. The plaque buildup restricts blood flow to the brain, leading to reduced oxygen supply and tissue damage, characteristic of a stroke. This representation highlights the potential consequences of carotid artery disease, emphasizing the importance of managing plaque buildup to prevent stroke and other related complications.

 

What This Study Tells Us

The study published on March 7, 2024, in the New England Journal of Medicine (linked here) revealed a significant potential connection between plastic particles found within cholesterol plaques of individuals with narrowed carotid arteries. This intriguing study underscores the widespread presence of plastics in our environment, which, once released into nature, tend to degrade into minuscule fragments. In this investigation, these fragments, categorized as microplastics (less than five millimeters) and nanoplastics (less than 1000 nanometers), were closely examined.

This study explored the relationship between these tiny microplastics and nanoplastics (MNPs), found in carotid artery plaque and the likelihood of cardiovascular events. Researchers conducted a thorough investigation involving patients with asymptomatic carotid artery disease who were scheduled for carotid endarterectomy.

They examined the removed plaque samples using various advanced techniques, including electron microscopy, to detect the presence of MNPs and evaluate inflammatory biomarkers in the samples. The main goal was to determine whether the presence of MNPs was associated with an increased risk of heart attack, stroke, or death.

 

Findings

This study, which included 312 patients who underwent carotid endarterectomy, showed that microplastics and nanoplastics were detectable in the excised plaque of 58% of the patients.

Patients with evidence of MNPs were younger, more likely to be men, less likely to have hypertension, more likely to have diabetes, cardiovascular disease, and dyslipidemia, and more likely to smoke.

 

The presence of microplastics or nanoplastics in carotid artery plaque was associated with a subsequent risk of nonfatal myocardial infarction, nonfatal stroke, or death from any cause that was 2.1 times that in patients whose plaques did not contain microplastics or nanoplastics.

 

How do plastics enter our bodies?

Based on the information provided by the study authors, the sources of microplastics and nanoplastics (MNPs) are as follows: ​

  1. Plastic production: The production of plastics is constantly increasing, leading to the widespread distribution of plastic particles in the environment. ​ Plastics can enter the environment through various means, such as ocean currents, atmospheric winds, and terrestrial phenomena. ​
  2. Degradation of plastics: Once released into nature, plastics are susceptible to degradation, forming microplastics (particles smaller than 5 mm) and nanoplastics (smaller than 1000 nanometers). ​ This degradation can occur due to various factors, including exposure to sunlight, mechanical abrasion, and chemical breakdown.
  3. Human activities: Microplastics and nanoplastics can enter the body through ingestion, inhalation, and skin exposure. ​ Humans can be exposed to MNPs through various sources, such as contaminated food and water, air pollution, and contact with plastic-containing products. ​

 

Transportation of plastics:

  1. Ingestion: MNPs can enter the human body by ingesting contaminated food and water. ​ Plastics can accumulate in the gastrointestinal tract and interact with tissues and organs.
  2. Inhalation: MNPs can also enter the body through air pollution inhalation. ​ Plastic particles can be present in fine particulate matter (PM2.5) and transported long distances by wind. ​
  3. Skin exposure: MNPs can interact with the skin and potentially penetrate the body through dermal absorption. ​

 

Plastic Particles in Cholesterol Plaques Linked to Poor Outcomes Heart Matters

 

Study Implications

The present study provides strong evidence to link these plastics to cardiovascular disease. The study’s findings suggest that patients with detectable MNPs in their carotid artery plaques are at a higher risk of cardiovascular events than those without MNPs. Moreover, the study highlighted that MNPs could trigger toxic effects and increase inflammatory biomarkers in plaque, further escalating the risk of adverse cardiovascular outcomes.

According to an accompanying Editorial by Dr Philip J. Landrigan, M.D:

 

Although we do not know what other exposures may have contributed to the adverse outcomes among patients in this study, the finding of microplastics and nanoplastics in plaque tissue is itself a breakthrough discovery that raises a series of urgent questions.

 

Conclusion

In conclusion, this study illuminates the correlation between microplastics and nanoplastics (MNPs) found within carotid artery plaques and the heightened risk of cardiovascular events. The findings underscore the potential negative impacts of plastic pollution on human health, raising the issue that these considerations extend beyond climate and environmental impact to affect human cardiovascular outcomes directly.

Addressing plastic pollution and its repercussions on human health is critical in safeguarding cardiovascular well-being and public health. Further research is crucial to understand better the mechanisms underlying these associations and to develop effective strategies for mitigating the adverse effects of plastic pollution on cardiovascular health.

Search articles

Newsletter

Subscribe for exclusive heart health resources, valuable tips, and the latest research updates.

Editor's Picks

Empowering heart health

Subscribe to our newsletter and be the first to receive valuable insights, tips, and resources on heart health.

other anti-anginals

When first-line therapies for angina, such as beta blockers, calcium channel blockers, and nitrates, prove inadequate or are not well-tolerated, second-line therapies may be considered.
Perhexiline is a unique medication that enhances the heart's ability to utilize fatty acids for energy, reducing its reliance on oxygen and lowering oxygen demand. This action helps improve blood flow and alleviates chest pain in some patients with refractory angina.
Nicorandil is another second-line option with a dual mechanism of action. It opens potassium channels in smooth muscle cells, causing vasodilation and enhancing coronary blood flow. Additionally, nicorandil also stimulates nitric oxide release, further dilating blood vessels and reducing heart workload.
Trimetazidine is an anti-ischemic agent that improves cardiac efficiency by enhancing glucose metabolism and shifting the heart's energy production to a more oxygen-efficient process. As second-line therapies, these medications offer alternative approaches for managing angina in individuals who do not respond adequately to first-line treatments or those experiencing side effects from other medications.

lipid lowering therapies

Lipid-lowering therapies play a critical role in managing coronary artery disease (CAD), a condition characterized by the narrowing of blood vessels that supply the heart. Among the most commonly discussed and debated classes of medications are statins, which effectively reduce cholesterol levels and are widely prescribed to lower the risk of cardiovascular events. Alongside statins, other medications like ezetimibe, fibrates, and niacin are also utilized to target specific aspects of lipid metabolism, such as cholesterol absorption, triglyceride levels, and raising high-density lipoprotein (HDL) cholesterol. Additionally, the introduction of medications that inhibit PCSK9, an enzyme involved in cholesterol metabolism, has provided a promising new approach to further lower LDL cholesterol levels. These PCSK9 inhibitors, such as Repatha (evolocumab), have shown significant efficacy in reducing LDL cholesterol levels in patients with CAD, especially for those who may not respond well to traditional therapies.

Nitrates

Nitrates are widely used to treat angina and provide quick relief for chest pain. Commonly available in the form of sublingual sprays or tablets, patches, and long-acting tablets, nitrates work by dilating blood vessels, allowing for increased blood flow and reduced resistance. This dilation eases the heart's workload, leading to a decreased demand for oxygen and prompt alleviation of angina symptoms. Sublingual nitrates act rapidly and are often used to provide immediate relief during angina attacks, while patches and long-acting tablets are employed for preventive purposes. However, nitrates may cause side effects such as headaches, dizziness, and flushing, which usually subside over time.

calcium channel blockers

Calcium channel blockers, including amlodipine, felodipine, cardizem (diltiazem), and verapamil, are commonly prescribed for the treatment of angina. These medications work by inhibiting the influx of calcium into the muscle cells of the heart and blood vessels, leading to their relaxation. As a result, blood vessels widen, promoting improved blood flow and reduced blood pressure. In the context of angina, this relaxation decreases the heart's workload, lowering the demand for oxygen and alleviating chest pain. Calcium channel blockers offer a valuable treatment option for individuals with angina, but it is essential to be aware of potential side effects, which may include headaches, dizziness, flushing, and ankle swelling.

Beta blockers

Beta blockers, such as metoprolol, propranolol, atenolol, carvedilol, and bisoprolol, play a crucial role in treating angina. By blocking certain receptors in the heart, they effectively reduce heart rate and the force of contraction, thereby easing the heart's workload. This mechanism of action leads to a decreased demand for oxygen, making beta blockers highly effective in relieving chest pain associated with angina. As with any medication, it's important to consider potential side effects, including tiredness, worsened asthma, erectile dysfunction in some males, and more vivid dreams during sleep. Consult your healthcare provider to determine the suitability of beta blockers for managing your angina and overall heart health.

Anti-platelet Medications

Anti-platelet medications play a crucial role in preventing blood clot formation, reducing the risk of serious cardiovascular events such as heart attacks and strokes. Among the widely used anti-platelet drugs are aspirin, clopidogrel, and ticagrelor.

Aspirin: This well-known medication inhibits platelet activation, making it less likely for platelets to stick together and form clots. Aspirin is commonly used for primary and secondary prevention of heart attacks and strokes.

Clopidogrel: As a potent anti-platelet agent, clopidogrel works by blocking specific receptors on platelets, preventing them from aggregating. It is often prescribed to patients with acute coronary syndrome, those undergoing stent procedures, and for some cases of peripheral arterial disease.

Ticagrelor: Ticagrelor is another effective anti-platelet drug that works by inhibiting platelet activation. It is used in acute coronary syndrome, often given alongside aspirin to reduce the risk of heart-related events.