(Photo from Flickr/Oregon State University)

Plastics are ubiquitous materials in our environment, and according to research, fragments of these materials have already permeated key aspects of human life – from food and water to the air we breathe.

Related: New study digs deeper into harmful effects of microplastics consumption 

Microplastics and nanoplastics (MNPs) are emerging as potential risk factors for cardiovascular disease in preclinical studies. However, direct evidence that this risk extends to humans is lacking, as indicated by a recent study published in the New England Journal of Medicine, funded by the Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale and others.

Related: Plastics found for the first time in human bloodstream

The study, led by researchers including Drs. Raffaele Marfella, Francesco Prattichizzo, Celestino Sardu, Gianluca Fulgenzi, Laura Graciotti, Tatiana Spadoni, Nunzia D’Onofrio, Lucia Scisciola, Rosalba La Grotta, Chiara Frigé, Valeria Pellegrini, Maurizio Municinò, and others, conducted a “prospective, multicenter, observational” study.

This study involved over 200 patients undergoing carotid endarterectomy (CEA), a surgery performed to reduce the risk of stroke in patients with known cerebrovascular atherosclerotic disease and asymptomatic carotid artery disease. Carotid arteries are major blood vessels that supply blood to the brain. The excised carotid plaque specimens were analyzed for the presence of MNPs using pyrolysis–gas chromatography–mass spectrometry, stable isotope analysis, and electron microscopy. Inflammatory biomarkers were assessed using enzyme-linked immunosorbent assay and immunohistochemical assay. The primary endpoint was a composite of myocardial infarction, stroke, or death from any cause among patients with evidence of MNPs in plaque compared to patients with plaque showing no evidence of MNPs.

Polyethylene (PE) was detected in the carotid artery plaque of 150 patients (58.4%), with a mean level of 21.7±24.5 μg per mg of plaque, while 31 patients (12.1%) also had measurable amounts of polyvinyl chloride, with a mean level of 5.2±2.4 μg per mg of plaque. Electron microscopy revealed visible, jagged-edged foreign particles among plaque macrophages and scattered in the external debris. Radiographic examination showed that some of these particles included chlorine. Patients in whom MNPs were detected within the atheroma were at a higher risk for a primary endpoint event than those in whom these substances were not detected (hazard ratio, 4.53; 95% confidence interval, 2.00 to 10.27; P<0.001).

The study found that patients with carotid artery plaque containing microplastics and nanoplastics (MNPs) had an increased risk of experiencing a combination of heart attacks, strokes, or death from any cause during a 34-month follow-up period, compared to patients without detected MNPs.

Source: The New England Journal of Medicine

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Silent heart attacks, known as silent myocardial infarction (SMI), account for 45% of heart attacks. They are described as “silent” because they occur without the usual, recognisable symptoms of a heart attack; but can still lead to a myriad of more serious – and potentially fatal – health complications if left untreated over an extended period.

In line with this year’s World Heart Day theme of “Use Heart for Every Heart,” Sunway Medical Centre, Kuala Lumpur, seeks to empower Malaysians to take care of their cardiovascular health by highlighting the possible dangers of a silent heart attack and how one can be swiftly spotted and prevented. 

Dr. Patrick Tiau, Consultant Cardiologist at Sunway Medical Centre, has highlighted that in recent years, cardiovascular disease has remained the leading cause of death both in Malaysia and globally. However, Dr. Patrick informed that nearly half of all heart attacks are mistaken for less serious problems and can increase one’s risk of losing their lives to coronary disease.

“We have come across many patients who have dismissed the early warning symptoms as simply feeling tired, indigestion, nausea, or sweating. By the time they seek out medical treatment for these symptoms, they are shocked to learn that what they are experiencing is actually due to a reduced blood flow to their heart, and that has caused them to have a silent heart attack,” Dr. Patrick said.

Typical symptoms of heart attack include chest pain often described as a weighted sensation; radiating pain in the arm, neck, or jaw; sudden shortness of breath; sometimes, sweating and dizziness might not be present.

Dr. Patrick explains that we can generally get a clearer picture of risk factors by looking at two categories: non-modifiable risks vs modifiable risks, i.e., lifestyle adjustments. 

Factors that Cannot be Changed (Non-modifiable)

Age

The risk of experiencing a silent heart attack increases as an individual grows older.

Gender

Men have been noted to be more susceptible to incidents of silent heart attacks than women. However, women are more prone to a higher risk of complications after experiencing one, especially if they are diabetic. 

Genetics

People who have a family history of heart disease are at increased risk of a heart attack. 

• Factors that Can be Changed (Modifiable)

Smoking

Chemicals in cigarettes stimulate one’s heartbeat and can dramatically increase one’s risk of heart attack.

High cholesterol

Individuals with elevated cholesterol levels can form atherosclerotic plaque in their blood vessels, which reduces blood flow to the heart. 

High blood pressure

Having high blood pressure puts extra strain on the heart muscle which, over time, causes the heart muscle to stiffen, thicken and perform less optimally.

Body weight

Individuals who are overweight or obese, especially when their weight tends to sit at the waist, are more likely to develop heart disease even if they do not have any other risk factors.

Physical inactivity

Regular exercise helps protect the heart by keeping other risk factors in check, including cholesterol, blood pressure, diabetes, and obesity. 

For patients who have experienced a silent heart attack, Dr. Patrick emphasised the importance of thorough cardiac evaluation and cardiac risks optimisation, which include consistently taking the necessary prescribed medications.

 “Once you go home from the hospital, it is essential that you keep taking your medications as prescribed, as these will ensure your heart health is kept in check, possibly for the rest of your life.”

As for the mental repercussions of silent heart attacks that patients may go through, including feelings of shock, sadness, and anxiety, Dr. Patrick assures that this occurrence is normal, and advocates the right type of support for those feelings to pass.

“Some people find it helpful to join a support group where they can talk with others who have been through a similar experience or seek out companionship and encouragement through avenues such as the gym, or yoga classes.”

Whether it’s a common or silent heart attack, even making small changes to our daily lifestyles can go a long way in reducing one’s risk factors. Such as regularly monitoring blood pressure and cholesterol; getting sufficient, aerobic exercise; quitting smoking; eating a balanced diet of fruit, vegetables, lean meats and whole grains, ensure that one’s blood pressure, cholesterol and blood sugar are well-controlled.

“Undeniably our heart health is essential to allowing us to have a well-balanced and fulfilling life. The heart itself is the first and last sign of life that is responsible for, quite literally, keeping us going. In combatting heart attacks, the most important thing to remember is that prevention is definitely better than cure,” Dr. Patrick advised. 

Most importantly, informing a doctor as soon as possible about any unusual symptoms can help diagnose silent heart attacks through specialised testing, such as with an ECG, echocardiograms, CT coronary or angiograms, as well as cardiac markers and exercise stress testing.

For some, experiencing things in silence denotes a sense of calmness and tranquillity. Silence can be beneficial for many things: meditation, reading, even prayer. However, in other circumstances ‘silence’ can mean that something dangerous is brewing under the surface, something we do not always notice in time – especially when it comes to our health.

In line with this year’s World Heart Day theme of ‘Use Heart for Every Heart’, Sunway Medical Centre seeks to empower Malaysians to take care of their cardiovascular health by highlighting the possible dangers of a silent heart attack and how one can be swiftly spotted and prevented.

Dr Patrick Tiau, Consultant Cardiologist at Sunway Medical Centre, Sunway City highlights that in recent years, cardiovascular disease has remained the leading cause of death both in Malaysia and globally. “A key factor in this is that nearly half of all heart attacks are mistaken for less serious problems and can increase one’s risk of losing their lives to coronary disease,” Dr Patrick says.

Silent heart attacks, known as silent myocardial infarction (SMI), account for 45% of heart attacks. They are described as “silent” because they occur without the usual, recognisable symptoms of a heart attack. Typical symptoms of heart attack include chest pain often described as heavy or pressure sensation; radiating pain in the arm, neck, or jaw; sudden shortness of breath; sweating, and dizziness might not be present. This has led to many not knowing that they experienced a heart attack until they receive diagnosis days or weeks after.

Dr Patrick says “We have come across many patients who have dismissed the early warning symptoms as simply feeling tired, indigestion, nausea or sweating. By the time they seek out medical treatment for these symptoms, they are shocked to learn that what they are experiencing is actually due to a reduced blood flow to their heart, and that has caused them to have a silent heart attack.”

Silent heart attacks are not benign as they can lead to a myriad of more serious health complications if left untreated over an extended period such as heart failure. If further neglected, it could also lead to an increased risk of another heart attack, which could potentially be deadly.

When assessing risk factors in different demographics, Dr Patrick explains that we can generally get a clearer picture by looking at two categories: non-modifiable risks vs modifiable risks, i.e., lifestyle adjustments.

Factors that Cannot be Changed (Non-modifiable)

–        Age: The risk of experiencing a silent heart attack increases as an individual grows older.

–        Gender: According to a 2021 study, men are more susceptible to incidents of silent heart attacks than women. However, women are more prone to a higher risk of complications after experiencing one, especially if they are diabetic.

–        Genetics: People who have a family history of heart disease are at increased risk of a heart attack.

Factors that Can be Changed (Modifiable)

–        Smoking: Chemicals in cigarettes stimulate one’s heartbeat and can dramatically increase one’s risk of heart attack.

–        High cholesterol: Individuals with elevated cholesterol levels can lead to formation of atherosclerotic plaque in the blood vessel and reduce blood flow to the heart.

–        High blood pressure: Having high blood pressure puts extra strain on the heart muscle which, over time, causes the heart muscle to stiffen, thicken and perform less optimally.

–        Body weight: Individuals who are overweight or obese, especially when their weight tends to sit at the waist, are more likely to develop heart disease even if they do not have any other risk factors.

–        Physical inactivity: Doing regular exercise helps protect the heart by keeping other risk factors in check, including cholesterol, blood pressure, diabetes, and obesity.

As with many critical illnesses, Dr Patrick advocates for Malaysians to take preventative measures first and foremost.

“Undeniably our heart health is essential to allowing us to have a well-balanced and fulfilling life. The heart itself is the first and last sign of life that is responsible for, quite literally, keeping us going. In combatting heart attacks, the most important thing to remember is that prevention is definitely better than cure,” Dr Patrick says.

Whether it’s a common or silent heart attack, even making small changes to our daily lifestyles can go a long way in reducing one’s risk factors. Such as regularly monitoring blood pressure and cholesterol; getting sufficient, aerobic exercise; quitting smoking; eating a balanced diet of fruit, vegetables, lean meats and whole grains, ensure that one’s blood pressure, cholesterol and blood sugar are well-controlled.

Most importantly, informing a doctor as soon as possible about any unusual symptoms can help diagnose silent heart attacks through specialised testing, such as with an ECG, echocardiograms, CT coronary or angiograms, as well as cardiac markers and exercise stress testing.

For patients who experienced a silent heart attack, Dr Patrick emphasises the importance of thorough cardiac evaluation and cardiac risks optimisation, which include the necessary prescribed medications.

“Once you go home from the hospital, it is essential that you keep taking your medications, as these will ensure your heart health is kept in check, possibly for the rest of your life.”

Amongst these medications, the most common types prescribed may include aspirin, statin and others such as beta blockers, and ACE inhibitors, depending on specific risk factors.

Dr Patrick also acknowledges the mental side of silent heart attacks that patients may go through. “After the stress of the initial diagnosis and recovery, you may start to develop feelings of shock, sadness, and anxiety,” he explains. 

He assures that this occurrence is normal, and it is important to remember that these feelings can pass with the right support. “Some people find it helpful to join a support group where they can talk with others who have been through a similar experience or seek out companionship and encouragement through avenues such as the gym, or yoga classes.”

A heart attack is one of the most unimaginably daunting things a person can go through, and what makes it even more so is that heart attacks can happen without us even realising. However, by educating ourselves through the right medical channels and by making sure we go for regular medical check-ups, we can ensure that our hearts remain beating strong and consistently for years to come.

The accumulation of damaged proteins contributes to ageing and disease – protecting against it requires boosting a cellular housekeeping process known as chaperone-mediated autophagy (CMA). CMA keeps cells functioning normally by selectively degrading the damaged proteins contained in cells.

The process was first discovered in 1993 by Dr. Ana Maria Cuervo, a Professor of Developmental and Molecular Biology and of Medicine, and Co-director of the Institute for Aging Research at Albert Einstein College of Medicine. Dr. Cuervo has shown that CMA regulates numerous intracellular processes including glucose and lipid metabolism, circadian rhythms, and DNA repair – an example of a faulty process is atherosclerosis, the buildup of plaque (a sticky substance consisting of fat, cholesterol, calcium, and others) within the walls of arteries.

In atherosclerosis, plaque deposits hardens and narrows arteries, impairing their key function of delivering oxygenated blood throughout the body. This can lead to events such as heart attacks and strokes, which are major factors of cardiovascular disease (CVD).

To investigate CMA’s role in atherosclerosis, Dr. Cuervo and colleagues promoted atherosclerosis in mice by feeding them a fat-heavy diet for 12 weeks and monitoring CMA activity in the animals’ aortas. CMA activity initially increased in response to the dietary challenge; but after 12 weeks, plaque buildup was significant, and virtually no CMA activity could be detected in either of two types of cells – macrophages and arterial smooth muscle cells.

“CMA seemed to be very important in protecting macrophages and smooth muscle cells — helping them function normally despite the pro-atherosclerotic diet — at least for a while, until their CMA activity basically came to a halt,” said Dr. Cuervo.

CMA-boosted mice, however, had greatly improved blood lipid profiles, with markedly reduced levels of cholesterol than control mice. Conversely, plaques nearly 40% larger formed in mice totally lacking in CMA activity; they were also fed a high-fat diet.

There is evidence that weak CMA activity correlates with atherosclerosis in people too.

Dr. Cuervo and her colleagues noted CVD patients with higher levels of CMA after a carotid endarterectomy, a surgical procedure that removes plaque-affected segments of their carotid arteries, were spared a second stroke. “[…] your CMA activity level post-endarterectomy could help in predicting your risk for a second stroke and in guiding treatment, especially for people with low CMA,” Dr. Cuervo said.

Fortunately, people won’t need a genetic alteration to increase CMA activity as Dr. Cuervo and colleagues have developed drugs for this purpose.

Read: Heart attack predictions made by AI-powered tool

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