Investigating the impact of polyaromatic hydrocarbon pollutants on heart function

Air pollution is associated with heart attacks, strokes and irregular heart rhythms, particularly in people already at risk for these conditions. Manchester research funded by the British Heart Foundation aims to learn more about the effects of a specific type of pollutants on our health.

The problem

Polycyclic aromatic hydrocarbons (PAHs) are chemicals that occur naturally in fuels such as coal, oil, petrol and wood. When released through the burning of these fuels, they form particulate matter (PM) in the air.

These microscopic solids or liquids are harmful to health. They can get into the deep part of the lungs and can even get into the bloodstream. In the UK, around 11,000 deaths each year are due to heart and circulatory diseases attributable to air pollution by PM, making it a significant public health issue.

Addressing the lack of research

There has been little study of the chemical toxicity of individual PAHs in air pollution, and there is currently little regulation of these compounds.

Through our British Heart Foundation-funded research, we hope to provide insight and stimulate more research in this area to fill current knowledge gaps, which will ultimately allow more informed air quality management to help reduce air pollution-associated cardiac risk.

Studying the effects of marine pollution

Our initial work on PAHs studied marine pollution after the Deepwater Horizon Oil spill, in collaboration with Stanford University. We analysed the effects of an individual PAH (phenanthrene) from the crude oil, on fish hearts. 

Our research showed that phenanthrene was a key factor in disrupting the heart function of fish exposed to oil pollution. 

Insights into effects on human health

While air and aquatic pollution differ, the processes in the fish heart that were affected by the phenanthrene are common across all vertebrate hearts, including humans, so clear parallels exist. 

Professor Holly Shiels explains: "Due to the conserved nature of cardiac function among animals, fish exposed to PAH from oil spills can serve as sentinels, providing insights into the human health impacts of PAHs and PM air pollution." 

Our findings were also important because phenanthrene is a significant component of air pollution in urban areas. 

Furthering scientific understanding 

We have since carried out further work to understand in detail the extent and mechanisms of PAH-mediated-cardiotoxicity, using a zebrafish model. The zebrafish heart works similarly to a human heart and is therefore a good model to use. 

We have shown that this compound, which is ubiquitous in polluted air and water, impacts ion channels in the heart, making it more prone to arrhythmias (irregular hearbeat). More recently, we have shown that these compounds are also proarrhythmic in mice.

Future aims 

In the future, we hope our findings will lead to policy changes, which will reduce air pollution associated with cardiac risk. Our research may also inform future treatment of PAH-induced cardiac health problems.