Bacteria Reveals How Stress and Fear Triggers Heart Attacks: Biofilms

There may be a reason why stress, emotional shock or even overexertion can help trigger heart attacks. Scientists have found that hormones released during these events may cause bacterial biofilms on arterial walls to disperse, which allows plaque deposits to rupture into the bloodstream.

In order to learn a bit more about how stress might impact heart attacks, the researchers isolated and cultured different species of bacteria from diseased carotid arteries that had been removed from patients with atherosclerosis. In the end, the scientists found multiple bacterial species living as biofilms in the walls of every plaque-covered carotid artery tested.

Under normal conditions, biofilms are resistant to antibiotic treatment and clearance by the immune system. But when they receive a molecular signal, the biofilms undergo dispersion and release enzymes to digest the scaffolding that maintains the bacteria within the biofilm. These enzymes have the potential to digest the nearby tissues that prevent the arterial plaque deposit from rupturing into the bloodstream.

"Our hypothesis fitted with the observation that heart attack and stroke often occur following an event where elevated levels of catecholamine hormones are released into the blood and tissues, such as occurs during sudden emotional shock or stress, sudden exertion or overexertion," said David Davies, one of the researchers, in a news release.

The findings reveal that stress can cause biofilms to undergo dispersion. This dispersion could cause the sudden release of the surrounding arterial plaque and, in turn, trigger a heart attack. This means that the bacteria should be considered to be part of the overall pathology of artherosclerosis. In addition, management of bacteria within an arterial plaque lesion could be as important as managing cholesterol.

The findings reveal a little bit more about what might trigger heart attacks and the reasons why stress could play a role. This could help with future preventative measures when it comes to managing heart attacks and improving heart health.

The findings are published in the journal mBio.