Bacteria in the bloodstream could play a role in heart attacks triggered by acute stress, emotional shock or overexertion, say David Davies and his colleagues of the Binghamton University in New York. The hormones excreted during stress causes bacteria to release enzymes that break down their own biofilm. Potentially, these enzymes also cause plaque deposits to rupture in the bloodstream, leading to a heart attack. The results were published this week in mBio, the online open-access journal of the American Society for Microbiology.
It is known that heart attacks often occur as the result of acute stress. In these moments, the stress hormone norepinephrine is released into the bloodstream. When exposed to a dose equal to the amount of released norepinephrine at moments of stress, at least one bacterium, Pseudomonas aeruginosa, broke down its own biofilm. Davies collected several bacteria colonies from the vessel wall of deceased persons arteries that were covered in plaque.
It’s the first time that biofilm bacteria were observed in the walls of arteries. The enzymes that bacteria release as a reaction to norepinephrine potentially can digest the tissue normally preventing plaque deposits from rupturing into the blood stream, which could cause heart attacks. This hypothesis might explain why heart attacks occur in moments of stress, shock or overexertion.
Whether the bacteria really break down the wall of plaque deposits has to be further investigated. The results of this study could suggest that the regulation of bacteria colonies in the blood stream could be of equal importance as regulating cholesterol levels is in preventing heart attacks.