New Research Suggests Dormant Bacteria in Arterial Plaques May Trigger Heart Attacks

Recent groundbreaking research from Tampere University and collaborating institutions in Finland and the UK has provided compelling evidence that heart attacks, specifically myocardial infarctions, could be caused by infectious agents residing within arterial plaques. This discovery challenges the traditional view that atherosclerosis and subsequent heart attacks are solely driven by lipid accumulation and oxidation of low-density lipoprotein (LDL) particles.

The study reveals that cholesterol-laden atherosclerotic plaques can harbor dormant bacterial biofilms, formed by oral bacteria, that have remained asymptomatic for years or even decades. These biofilms are protected within the plaque matrix, shielding the bacteria from the immune system and antibiotics, which makes them difficult to eradicate. Under certain external triggers, such as viral infections or physiological stressors, these bacteria can become active, leading to an inflammatory response.

Activation of dormant bacteria causes inflammation that may weaken the fibrous cap of the plaque, leading to rupture. Such rupture exposes the plaque's contents to the bloodstream, promoting clot formation and ultimately resulting in a myocardial infarction. The study's lead, Professor Pekka Karhunen, explained that this bacterial involvement in coronary artery disease had been suspected but lacked direct evidence until now.

Using advanced genetic analysis, the researchers detected DNA from oral bacteria within arterial plaques. They further validated their findings by developing specific antibodies that revealed bacterial biofilms in arterial tissue. Interestingly, bacteria were observed to be released from these biofilms during incidents of myocardial infarction, indicating an active role in plaque rupture.

This research advances our understanding of heart attacks as potentially infectious disease processes and opens doors for novel diagnostic methods and treatments. It also raises exciting possibilities for prevention through vaccination against specific bacteria implicated in the formation of these biofilms.

The findings, published in the Journal of the American Heart Association, could revolutionize how we approach cardiovascular disease, focusing not only on lipid management but also on microbial factors. Future therapies may include targeted antimicrobial treatments or vaccines aimed at preventing bacterial colonization in arterial plaques.

Source: https://medicalxpress.com/news/2025-08-heart-triggered-dormant-bacteria-arterial.html