The heart of young urban dwellers contains millions of toxic air pollution particles, research has revealed.
Even in the study's youngest substance, who was three, injuries could be seen in the cells of the organs' critical pump muscles containing the small particles. The study suggests that these iron-rich particles, produced by vehicles and industry, could be the root cause of the long established statistical link between dirty air and heart disease.
The scientists said that nanoparticles abundance can pose a serious public health issue and that particle air pollution must be reduced urgently. More than 90% of the world's population lives with toxic air, according to the World Health Organization, which has explained the issue to a global "public health situation".
The researchers recognized some uncertainty in their research, but Prof Barbara Maher, of Lancaster University, said: "This is a preliminary study in one way, but the results and consequences were too important not to get the information out there."
While all ages were affected, Maher said she was particularly concerned about children.
"For really young people, the evidence is now of much damage in the early stages both in the heart and brain," she said. "We have a probable candidate [particle] able to access both bodies, with the pathological evidence that injuries occur".
A recent comprehensive review found that air pollution can damage every organ and virtually every cell in the human body, because small particles are inhaled, moved into the bloodstream and transported around the body. Much of the evidence of injury, from diabetes to impaired intelligence to increased miscarriage, is epidemiological, as harmful experiments on humans are unethical. But a study in 2018 found air pollution particles in the maternal bodies of women who were born.
The new research is the first direct proof that iron-rich nanoparticles can cause heart disease. Small particles were already known from laboratory tests to be serious injuries to human cells and to be a significant part of air pollution on the roads.
Maher said: "Placing an abundance of iron-rich nanoparticles directly into the subcellular components of the heart's muscle tissue is not where you want them to sit. They are inside mitochondria, which are damaged and seem abnormal. your energy source, so your heart pumps efficiently. "
Mark Miller, an expert on the air pollution cardiovascular effects, from the University of Edinburgh but not part of the research said:" Although there are some uncertainties from the study, it highlights how important it is is to better understand how particles in air pollution can damage various body parts.
"More effort is needed to reduce particle emissions from vehicles, especially to remove the number of vehicles on the road by encouraging people to walk and cycle for short journeys. "
The research, peer reviewed and published in the Environmental Research journal, analyzed cardiac tissue from 63 adolescents who had died in traffic accidents but had not suffered breast trauma. They lived in Mexico City, which has high air pollution and had an average age of 25 years.
The research was carried out in two main parts: calculating the number of iron-rich nanoparticles present, and looking at their location in the tissue and the associated lesions. 10 times higher in the population of Mexico City than in nine control subjects who had lived in less polluted sites. [Themedicalresearchersintheteamreportedthat"exposureto[nanoparticles] appears to be directly associated with early and significant cardiac damage. "
Maher said the results were relevant to all countries:" There is absolutely no reason to expect it to be different in any other city. "Based on past work, she said that the particles were also likely to carry additional pollutants." We can imagine that these nanoparticles will be loaded with a toxic mixture. " The particles in the heart tissue had these characteristics rather than small iron-rich magnetite crystals known to occur naturally in at least one organ, the brain. The technique used to locate the nanoparticles in the heart tissue could not be used to measure Instead, the researchers separated the particles from the tissues to determine their composition and magnetic content, and then used the particle size and magnetism to estimate the total number.
They said they would like to confirm the particle composition in situ in the cells, but it would require the use of expensive equipment and Maher said they had not received any funding for the work. "We have to do this on a shoestring. It's madness."