Air pollution is recognized as one of the top global health burdens having been associated with 3.2 million deaths per year. These deaths are primarily due to lung disease (43%) and lung cancer (29%) but there is a growing appreciation of the impact of air pollution on heart health. Indeed, the WHO states that 25% of the deaths contributed to air pollution come from heart disease complications. There have been numerous studies that have defined a relationship between air pollution and arrhythmias, hypertension, and heart attack. One way that air pollution can negatively influence our health and survival is by altering the normal growth and development of our organs during early life which puts us on a path towards disease as adults. This theory is known as the developmental origins of health and disease (DOHAD) principle and is thought to contribute to many chronic diseases. A team of researchers from the US turned to a mouse model in order to understand how exposure to air pollution during pregnancy and early life development might impact heart health in offspring.
The team exposed both male and female mice to particulate matter 2.5 microns in size (PM2.5), which is an important component of air pollution, at levels that mimic daily exposure in many major US cities. The animals were exposed to this air pollution for 3 months prior to conception and then the mice were bred. Male offspring, who were never directly exposed to air pollution, had their heart function measured at 3 months of age (adulthood in mice) as well as markers of inflammation and oxidative stress. The team found that male offspring whose parents had been exposed to air pollution had worse heart function (reduced contractility and ability to empty heart) and had significant markers of inflammation and fibrosis within the heart tissue. There was also a loss of oxidant/anti-oxidant balance within the hearts putting the hearts at greater risk of oxidative damage and more inflammation.
These intriguing results suggest that exposure to pollution prior to conception or pregnancy can have significant impacts on offspring health even if the offspring are never exposed to the same levels of air pollution. This has huge implications in nations where air pollution levels are out of control and could mean that a whole generation of yet unborn children could be at significant risk for chronic disease. As more data comes forward about the dangers of air pollution it becomes clear that we need to control this problem now for not only the health of our population but also the health of future generations. This isn’t just a problem for developing nations as research suggest that exposure to even ‘acceptable levels’ of air pollution is associated with an increased risk of death. Investment in clean, renewable energy and clean manufacturing processes is necessary to halt the growing pollution problem.