A new study has uncovered an unexpected cause for myocardial infarction (heart attack): a hidden bacterial infection. Researchers, whose work was published in the Journal of the American Heart Association (JAHA), analyzed atherosclerotic plaque samples from 217 patients with vascular diseases, finding that bacteria commonly residing in the oral cavity can contribute to heart attacks.
The results revealed that DNA from viridans streptococci was present in nearly half of the examined samples. These bacteria formed biofilms directly within the atherosclerotic plaques, effectively concealing themselves from the immune system. While the plaque remained intact, no immune response was triggered. However, upon its rupture, the bacteria were released into the surrounding tissues, activating TLR2 receptors and inducing strong inflammation. This process, in turn, could lead to the destruction of blood vessel walls and the development of a heart attack.
The scientists also noted that the presence of these bacteria was significantly more frequent in individuals with severe forms of atherosclerosis and those already suffering from cardiovascular diseases. This discovery highlights a potential link between chronic bacterial infections and an increased risk of serious complications, including fatal outcomes, in ischemic heart disease.
