THE ESSENTIAL
- Exposure to air pollution, especially fine particles, increases the risk of developing heart disease, insulin resistance or type 2 diabetes.
- For researchers, these changes are associated with changes in the epigenome but appear to be reversible.
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First environmental risk factor in the world, causing more than 8.8 million premature deaths per year, including 800,000 in Europe, air pollution is an aggravating factor cardiometabolic diseases.
This is what a new study published in the Journal of Clinical Investigation. According to its authors, members of the Cleveland University Hospitals Medical Center (United States), air pollution would be, like lack of physical exercise or a poor diet, a risk factor for cardiometabolic disease.
Cardiovascular diseases (atherosclerosis, infarction, heart failure, hypertension, etc.), when they develop in the same patient, are often associated with metabolic diseases, that is to say characterized by disturbances in metabolism, in particular sugars (diabetes) and lipids (obesity, dyslipidemia). We are therefore talking about cardiometabolic diseases or syndromes.
Insulin resistance
To study the impact of air pollution on cardiometabolic health, the researchers created an environment mimicking a polluted day in New Delhi or Beijing. They concentrated microparticles of pollution, called PM2.5 (that is to say, the diameter of which is less than 2.5 microns), and which traditionally come from cars, power generation and combustion of fossil material.
The research team wanted to show that exposure to air pollution can increase the likelihood of the same risk factors that lead to heart disease, such as insulin resistance and type 2 diabetes. For this, they have used a mouse model, divided into three groups: a control group of mice receiving clean filtered air, a group exposed to polluted air for 24 weeks, and a group fed a high-fat diet.
The researchers then found that the two groups exposed to air pollution and a high-fat diet both showed insulin resistance and abnormal metabolism, as can be seen in a prediabetic state.
Reversible effects
For the authors of the study, these changes are associated with changes in the epigenome, that is to say all the genetic modifications of cells, which therefore seem sensitive to environmental factors.
“The good news is that these effects were reversible, at least in our experiences., said Dr Sanjay Rajagopalan, first author of the work. Once the air pollution was removed from the environment, the mice appeared healthier and the prediabetic state seemed to reverse. “
The next steps in this research are to meet with a group of experts, as well as the National Institutes of Health, to discuss the conduct of clinical trials comparing heart health and the level of air pollution in the environment.
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