New target for anti-clotting drugs revealed

Monash University scientists, investigating how the size of blood clots is regulated, have identified a new target for anti-clotting drugs that could help in the treatment of patients at risk of heart attack or stroke.

The researchers, from the Australian Centre for Blood Diseases in Monash's Department of Medicine based at Box Hill Hospital, have found that calcium fluctuations in platelets - blood cells that stick to the site of an injury and seal off the wound - determine the size of blood clots in patients who have atherosclerosis (a build up of cholesterol in the arteries).

Patients with atherosclerosis are at risk of coronary blood clots that lead to heart attack or to cerebral blood clots that affect the brain and cause strokes.

"Some people's arteries are more prone to clotting than others," said Dr Shaun Jackson, who led the scientific team. "The primary determinant of this is the amount of collagen in their artery walls. When the blood vessels of patients with atherosclerosis are damaged, the rupturing of the atherosclerotic plaques causes collagen to be released."

The team found that, when platelets came to repair this damage by forming a clot, the clots were much larger.

"The platelets clump together by sending calcium signals to each other," Dr Jackson said. "When there is collagen present, as there is in patients with atherosclerosis, the calcium signaling between the platelets is much more efficient and larger clots form.

"This is a problem for patients with atherosclerosis as the larger the clot the greater its potential for blocking vital blood vessels and causing heart attack or stroke.

"Now that we understand how collagen is regulating calcium signaling and therefore controlling the size of clots, we have new targets for the development of anti-clotting drugs. We can now look for methods of impeding the calcium signaling so the clots don't grow as large. Another approach could be to block the collagen and make the blood vessels less responsive to the blood clotting mechanism."

Dr Jackson said any treatments would seek to dampen the clotting mechanism rather than block it altogether, as blood clotting is important to stop bleeding.

Item provided courtesy of Monash University