Scientists find why mouth bugs are bad for heart

The link between bacteria that cause dental plaque and heart disease and strokes is well known but scientists have now discovered just why it is that the microbes pose a far bigger risk than receding gums.

Once let loose in the bloodstream they deploy a protein that forces platelets to bind together and shield the bugs with clots.

Study leader Professor Howard Jenkinson, from the University of Bristol, said: “When the platelets clump together they completely encase the bacteria.

“This provides a protective cover not only from the immune system, but also from antibiotics that might be used to treat infection.

“Unfortunately, as well as helping out the bacteria, platelet clumping can cause small blood clots, growths on the heart valves, or inflammation of blood vessels that can block the blood supply to the heart and brain.”

Speaking at the Society for General Microbiology’s autumn meeting in Nottingham, Prof Jenkinson said oral bacteria can “wreak havoc” if not kept in check by brushing and flossing.

“Poor dental hygiene can lead to bleeding gums, providing bacteria with an escape route into the bloodstream, where they can initiate blood clots leading to heart disease,” he said.

The streptococcus bacteria normally live in confined communities in the mouth called biofilms which cause dental plaque and gum disease.

The bugs become far more potentially harmful once they break free of the mouth and enter the blood circulation.

“People need to be aware that as well as keeping a check on their diet, blood pressure, cholesterol and fitness levels, they also need to maintain good dental hygiene to minimise their risk of heart problems,” said Prof Jenkinson.

The team is using a new blood flow model developed by the Royal College of Surgeons in Ireland that mimics conditions in the human circulatory system.

The scientists are investigating how the platelet-activating behaviour of the bacteria can be blocked. This could eventually lead to new treatments for cardiovascular disease, the biggest killer in the developed world.

n The same meeting heard that similar tactics are used by food-poisoning listeria bugs. The bacteria, found in soft cheeses and chilled ready meals, are able to exploit certain food constituents such as the amino acid glutamate which allows the bugs to neutralise acid and pass through the stomach unscathed.