Scientists in Scotland are trying to find out why certain bacteria trigger gum disease, which puts people at a higher risk of having a heart attack.
The study at the University of Aberdeen, funded by the British Heart Foundation (BHF), will explore why some bacteria change from living harmlessly in the mouth to becoming “bad” and causing harmful inflammation, which can lead to health problems.
This research will help understand if treating gum disease stops these changes from happening and could help prevent someone from having a heart attack or developing heart disease.
Professor Karolin Hijazi, who is leading the study and is a trained dentist, explains: “It’s completely normal and healthy to have bacteria in your mouth but certain bacteria in the mouth can also turn bad. They can infect the gums, causing inflammation and bleeding. If left untreated, gum disease can lead to tooth loss and has also been linked to an increased risk of developing heart or blood vessel problems. But we still don’t really understand how bacteria linked to gum disease can cause cardiovascular disease and that is what we are trying to find out.”
61-year-old Mark Allen, from Bridge of Don, is among those involved in Professor Hijazi’s research. The retired oil and gas worker had a heart attack at home in November 2019.
He was taken to Aberdeen Royal Infirmary where he was found to have a blocked artery and had a stent inserted to improve the blood supply to his heart muscle. While in hospital he was asked if he would like to take part in the study.
Mark explains: “Having my heart attack was a real bolt out of the blue and so when I was offered the opportunity to take part, I immediately said yes. I wanted to understand more about what had happened to me and if there was anything I could do to improve my health going forward. Research like this is essential and I’m really proud of the work going on here in Aberdeen. It could lead to the discovery of new treatments and I felt it was important to help if I could. I am a great believer in putting back into the system to help others in the future.”
Professor Hijazi and her team are interested in how, under certain conditions, bacteria can switch on genes which can drive bacteria to cause disease, for example by getting into the blood stream or ‘hijacking’ our immune system, causing harmful inflammation. Inflammation is a normal part of the immune response to infection or injury, but when it becomes long-term and dysregulated, it can contribute to atherosclerosis – the process of fatty material building up in the arteries.
The project will focus on a particular type of bacteria called Porphyromonas gingivalis (P. gingivalis), which is known to be involved in the development of gum disease but has also been linked to coronary artery disease and heart attacks.
The team recently carried out a study of 160 people admitted to Aberdeen Royal Infirmary with a heart attack. About two-thirds of them had a severe gum infection. The study found that people with higher levels of P. gingivalis in their mouths tended to have more damage to their hearts.
Researchers also looked at levels of genes involved in the switch from the bacteria living harmlessly in the mouth to becoming ‘bad’ and causing inflammation. Expression of these genes was also increased in people with more severe heart damage and coronary artery disease.
The project, supported by a £290,000 grant from the BHF, will look into how P. gingivalis switches on its ‘bad’ genes, and whether this differs in people who have had, or are at a higher risk of, a heart attack.
Professor Hijazi and her team will be recruiting people who have recently had a heart attack, people with stable angina, and people without coronary artery disease. All those taking part will have a dental exam and samples taken from their mouth, so the researchers can analyse what is going on inside the P. gingivalis they find there.
Professor Hijazi added: “Finding a connection between how different genes are switched on and off and having a heart attack, may enable us to see if we can intervene to improve cardiovascular health. For example, does treating gum disease change the genes on-and-off pattern of bacteria in our mouths and does doing that reduce the risk of having a heart attack?
“More broadly, if we can show this mechanism in the context of gum disease and the heart, it could open a whole range of new avenues for other diseases. Could a similar way of switching genes on or off exist in gut bacteria? Could that help explain the links between oral, gut health and conditions like rheumatoid arthritis or Parkinson’s disease? It could make a huge difference in helping us understand how the trillions of microbes in our bodies can affect our health."
The BHF is the largest independent funder of research into heart and circulatory diseases in Scotland. The charity is currently funding more than £50 million in research in 10 universities across Scotland, including the University of Aberdeen and at its Centres of Research Excellence at the universities of Glasgow and Edinburgh.
David McColgan, Head of BHF Scotland, said:“This is an example of how cutting-edge research is helping transform our understanding of heart disease – research that is only made possible thanks to the incredible generosity of the public.”
This June, the BHF has launched a new campaign calling on the public to support research into heart and circulatory diseases. The campaign aims to inspire people’s wonder at the complexity and preciousness of their own hearts and how lifesaving research can help if it goes wrong. Find out more here: https://www.bhf.org.uk/this-is-science