Scientists, including an Indian researcher, have found a previously unknown stem cell which is the real culprit behind heart attacks, a landmark finding which, they say, could revolutionise treatments for the cardiac disease.

Until now, it has been thought that vascular health problems were triggered by smooth muscle cells, but a team at the University of California in Berkeley identified a previously unknown stem cell, which causes the arteries to harden when it multiplies.

The groundbreaking work is set to completely change how heart attacks and strokes are treated, dramatically cutting the number of deaths, the researchers said.

"For the first time, we are showing evidence that vascular diseases are actually a kind of stem cell disease," said Professor Song Li, who led the research.

"This work should revolutionise therapies for vascular diseases because we now know that stem cells rather than smooth muscle cells are the correct therapeutic target," Prof. Li was quoted as saying by the Daily Mail.

"This is groundbreaking and provocative work, as it challenges existing dogma," added his colleague Dr. Deepak Srivastava.

Heart attacks are the most common reason for people to need emergency treatment. More than 150,000 people a year have a stroke. Strokes occur when the blood supply to part of the brain is cut off, while heart attacks happen when the supply of blood to the heart is blocked, usually by a blood clot.

According to the researchers, who detailed their findings in the journal Nature Communications, the newly discovered vascular stem cells are multipotent – or capable of changing into various cell types, including smooth muscle, nerve, cartilage, bone and fat cells – explaining why previous studies misidentified the cells involved in vessel clogs.

"In the later stages of vascular disease, the soft vessels become hardened and more brittle,"said Prof Li.

"Previously, there was controversy about how soft tissue would become hard. The ability of stem cells to form bone or cartilage could explain this calcification of the blood vessels," Prof. Li added.