We have always known stress to be bad for the body and we also knew sustained stress could cause heart attacks and strokes but scientists have never understood exactly why.
A study by Dr Matthias Nahrendorf and his team at Massachusetts General Hospital and Harvard Medical School has suggested stress also sends the immune system into overdrive, increasing white blood cells and worsening inflammation in the arteries. This can cause huge problems if arteries are already thickened with plaque.
The damaged arteries produce lesions that can break away when they become more inflamed leaving an open wound that blood platelets and clotting proteins rush to fill. A clot can enlarge in moments and if it completely obstructs the artery, it will cause a heart attack.
The team also found out that junior doctors who were regularly exposed to chronic stress had very high white blood cell counts. They also found that when mice were stressed, stem cells were activated and produced large numbers of white blood cells.
An inhibitor drug that stopped stem cells from producing white blood cells was discovered by the team. The drug prevented the build-up of plaque in the arteries, offering hope for new treatment.
The findings were published in the journal, Nature Medicine.
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