Scientists recreate alveolar epithelium in a lab to understand how polluted air can affect your health

Even today, in a world increasingly powered by renewable energy and clean technologies, air pollution poses a real risk to human health. In the UK alone, it is estimated to be responsible for 28,000 to 36,000 deaths every year, and can vastly increase the risk of developing many lung and heart-related diseases, such as asthma or lung cancer.

Polluted air forms a complex mixture that changes depending on where the pollution is coming from, and what the local weather is doing at the time. People in towns and cities are more at risk since they live closer to most cars, factories and other sources of emissions.

Although there are many different types of pollutants within the air we breathe, two in particular are detrimental to our health: the gas nitrogen dioxide (NO₂) and particulate matter (specifically, PM_2.5), formed of floating, microscopic solid or liquid particles smaller than 2.5 micrometers in diameter (for reference, a human hair is about 70 micrometers in diameter).

In 2017, a report found that all areas of London exceeded World Health Organization recommended levels for PM₂.₅, with many areas being more than double the recommended levels. Scenarios like these have allowed researchers to investigate the dangers of breathing in really polluted air.

One study found that, across the world, 86% of people who live in urban areas are exposed to PM₂.₅ at levels higher than even the World Health Organization’s more lenient 2005 guidelines, resulting in 1.8 million excess deaths in 2019. Another found NO₂ to be responsible for 1.85 million cases of childhood asthma worldwide in 2019.

These figures come from studies on large populations of people, which take public health data and compare it to pollution data to look for correlations between pollution and disease. These are known as epidemiological studies. Although these studies can provide great insight into the risks associated with air pollution exposure, they do have their limitations.

For example, NO₂ and PM_2.5 are emitted from the same sources, so you’d expect that when levels of one pollutant are high, levels of the other are high too. Therefore, without some very complicated math, it’s sometimes hard to use epidemiological data to fully tease out the health effects of one pollutant compared to another.

For this reason, research needs to take place in a more controlled environment. This can be achieved in a laboratory setting either by using invasive animal testing strategies, or by implementing cell-based systems of human cells that represent the organ in a dish.

Lungs in a lab

In our lab at Swansea University Medical School, we are trying to replicate the layer of cells known as the alveolar epithelium, which lines the deepest part of your lungs where oxygen enters your bloodstream and carbon dioxide leaves as you breathe in and out. This means it’s also a key area that air pollution can target and damage. We therefore want to understand how pollution affects this specific and very delicate body part.

This article is republished from The Conversation under a Creative Commons license. Read the original article.