The hearts of people living in urban areas, even those as young as three, are filled with highly toxic air pollution particles, putting them at a massive and increased risk of cardiac disease, according to researchers. The study - which is the first to identify the presence of billions of strongly magnetic nanoparticles in the hearts of children and young adults - says exposure to this type of metal-rich nanoparticles appears to be directly associated with "early and significant” inflammation and cardiac damage or heart-related diseases.
The research - led by Professor Lilian Calderón-Garcidueñas from the University of Montana (US) and Professor Barbara Maher from Lancaster University (UK) - is the first direct proof that magnetic nanoparticles may cause heart disease. The team found that the toxic nanoparticles were present in many different cell structures in the left ventricle of the heart, as well as the mitochondria, which is critical for supplying the energy needed for the heart to pump effectively.
“Strongly magnetic nanoparticles, strikingly similar to the magnetic combustion- and friction-derived nanoparticles (CFDNPs), which are abundant in the
urban atmosphere, especially at major roadsides, occur in abundance in young urbanites’ hearts. The prolific presence of such iron-rich nanoparticles in cardiac cells might need to be considered as a serious public health concern,” says the study published in the journal Environmental Research.
According to the research team, these iron-rich, strongly magnetic nanoparticles, found in particulate air pollution, are created as a result of combustion and friction by vehicles and industry, including transport (road exhaust and brake-wear, rail and metro), metal processing and power generation plants. Exposure to air pollution is known to be associated with increased risk of cardiovascular and Alzheimer’s disease. Studies have shown that young residents of Metropolitan Mexico City (MMC) have “abundant brain CFDNPs associated with Alzheimer’s disease pathology”. Hence, the researchers decided to examine if such magnetic nanoparticles are present abundantly in human heart tissue and the subsequent damage they could be causing.
“They (nanoparticles) are toxic, and their toxicity relates to metals and their magnetic properties. Inhalation is a rapid and effective portal of entry of environmental nanoparticles. Inhaled nanoparticles reach the alveolar surface, cross the alveolar/capillary barrier, and reach the systemic circulation. At the alveolar/capillary barrier, nanoparticles are capable of hitchhiking red or white blood cells (WBC) and can reach any organ, including the heart. It is a common observation that the transportation of nanoparticles through red blood cells (RBC) boosts the delivery of nanocarriers. The RBC/WBC hitchhiking mechanism may be a key delivery platform for combustion and friction-derived nanoparticles (CFDNPs) to the brain and heart,” Dr. Calderón-Garcidueñas told MEA Worldwide (MEAWW).
The team examined the hearts of 72 people, aged between three and 32 years. While 63 of the hearts were taken from the victims of fatal road traffic accidents in heavily polluted Mexico City, the remaining nine were ‘control’ hearts from people who had lived elsewhere. The analysis showed that the hearts belonging to people who had lived in Mexico City contained much higher numbers of tiny particles or nanoparticles of pollution, from traffic (exhausts and brake systems) and industry. This, according to the researchers, shows that the hearts of people living in highly polluted urban areas could be up to ten times more polluted than those living in places with cleaner air, putting them at increased risk of heart disease.
To identify how much inflammation the heart tissues had been subjected to, the researchers examined the indicators of “oxidative stress”, and found that the heart nanoparticles were associated with damage to heart cells. “Many of these nanoparticles were strongly magnetic, posing particular potential risk of heart problems, which includes generation of oxidative stress and chronic inflammation, potential for disruption of the heart’s electrical impulse pathways, hyperthermia (the damaging overheating of tissues as particles try to rotate in response to magnetic fields), and potential disruption of cell membranes by magnetic particle rotation,” says the findings.
The findings in “seemingly healthy children and young adults”, say the team, provide a new way of understanding heart disease risks in high pollution-exposed urban populations and is critical for protecting vulnerable, exposed individuals.
“The health impacts of approximately 22 billion strongly magnetic NPs/g of ventricular tissue are likely to reflect the combination of surface charge, ferrimagnetism, and redox activity displayed by such nanoparticles, and includes their potential to disrupt the heart’s electrical impulse pathways, and hyperthermia and alignment and/or rotation in response to magnetic fields. The cellular and molecular mechanisms leading to the onset of cardiac dysfunction associated with high exposures to particulate matter, and specifically to these iron-rich nanoparticles, may share a common denominator: oxidative stress and the resulting signaling cascades, leading to direct and indirect effects on cardiac structure and function,” Dr. Calderón-Garcidueñas told MEAWW.
Dr. Calderón-Garcidueñas says that the main message from the study findings is that exposure to iron-rich combustion- and friction-derived nanoparticles is a modifiable risk factor for the development of cardiovascular diseases. “We need to reduce exposure to particulate matter air pollution and, specifically, regulate the ultrafine fraction. It is obvious this is going to be a major task, particularly in developing countries,” she says.
According to Dr. Partha Sarathi Mukherjee from the Boise State University (US), in India, in particular, the issue of combustion-derived particles is becoming more and more severe. “We see a lot of people burn garbage, dry leaves regularly in residential areas and open markets. Stubble burning in the north-western part of India during October-November is global news. Some people routinely burn various kinds of stuff to repel mosquitoes and other insects. The story goes on if you include incense sticks and other combustion sources. It is high time that scientists and other stakeholders draw the attention of common people and the governing bodies for building awareness and strict policies to prevent premature death of millions,” Dr. Mukherjee told MEAWW.