Researchers say they've shown how a stressful life can impact the body's immune system in a bad way, prompting changes with white cells to work against the human body instead of as immune-fighting machines. The weakened immune scenario is then ripe for diseases such as atherosclerosis that can lead to a heart attack.

Stress activates bone marrow stem cells that then kick the white blood cells, called leukocytes, into overdrive in terms of production. Too many white blood cells are not healthy as extra cells begin lining inner walls of arteries, blocking blood flow and causing blood clots.

The study was published this month in Nature Medicine.

White blood cells "are important to fight infection and healing, but if you have too many of them, or they are in the wrong place, they can be harmful," says study co-author Matthias Nahrendorf of the Harvard Medical School in Boston.

The study, conducted by researchers from Massachusetts General Hospital and Harvard Medical School, involved 29 medical residents employed in an intensive care unit, a stressful work environment. Researchers took blood samples during work hours as well as off-work hours.

The study comes on the heels of additional heart attack research. As Tech Times recently reported a single injection shot may lower the risk of heart attacks by 40 percent to 90 percent in humans; however, testing is currently done only on mice for now.

Scientists at the Harvard Stem Cell Institute are working with researchers from the University of Pennsylvania to develop a "genome-editing" approach, which can reduce cholesterol levels permanently and hence reduce the risk of heart attacks.

Kiran Musunuru of HSCI is leading the research and says the study is focusing on how to alter the function of PCSK9, a liver gene. Previous research has shown that PCSK9 is a cholesterol regulator, accountable for high cholesterol in humans and heart attacks.  

Musunuru says that PCSK9 gene is present mainly in the liver, which makes a protein that is active in the bloodstream. The protein averts cholesterol removal from the blood. A few drug companies are developing antibodies; however, antibody-based drugs do not last forever and patients will need to take drugs on a regular basis. Musunuru also highlighted that statin drugs can also be used to reduce cholesterol levels, but many people who take the drug on a daily basis have had heart attacks.

"What we were thinking was that, with this genome-editing technology, we can do something we couldn't do before: make permanent changes in the genome at the level of the DNA. We can actually go to the source. So the question was whether we can use genome editing to make normal people like people born with the 'good' mutations," says Musunuru.

The researchers say that many people worldwide die of heart attacks every year. Heart attacks are responsible for the deaths of many elderly people, as well as people aged over 40 years. If a single shot targets the liver and changes the genome responsible for heart attack, then it can also be taken as a vaccination in the future. A one-time treatment may permanently alter cholesterol levels in humans and reduce the occurrence of heart attacks.

Musunuru pointed out that it can take another decade of research before the new approach finds its way to testing and trials on human beings.