Experimental vaccine may reduce risk of post-stroke blood clot

Oct. 29 (UPI) -- An experimental vaccine reduced the risk of post-stroke blood clot risk in a study with mice, researchers report in a new study.

Researchers in Japan hope the vaccine, called S100A9, may one day replace oral blood thinners, which are used to help prevent another stroke. The findings were published Monday in the journal Hypertension.

In addition, they found that the vaccine also doesn't increase the risk of serious bleeding or lead to an autoimmune response.

"Many stroke patients don't take their blood thinning drugs as prescribed, which makes it more likely they will have another stroke," Hironori Nakagami, a professor at Osaka University and co-author on the study, said in a press release. "This vaccine might one day help solve this issue since it would only need to be injected periodically."

Among the 795,000 Americans who have a stroke each year, 25 percent will have another stroke within their lifetime, according to the National Stroke Association. Recurrent strokes have a higher rate of death and disability because portions of the brain were injured by the original stroke or may not be as resilient.

In addition to blood thinners, doctors may include an antiaggregant such as aspirin or anticoagulant such as warfarin to help prevent a secondary stroke.

For the new study, researchers found the experimental vaccine provided protection against blood clots in mice for more than two months, and it worked as well as the oral blood thinner clopidogrel in a major artery.

Researchers say the lack of an immune response means the mice's immune system did not perceive the vaccine as an "intruder" that needed to be attacked. This would have caused a reaction to the vaccine.

The researchers hope one day to conduct human trials of the vaccine.

"We are continuing our research in hopes of being able to start clinical trials between five and ten years from now, but there are differences between mice and humans in how the vaccine will be recognized by the immune system," he said. "We should be able to overcome such problems and believe this vaccine provides a very promising strategy in secondary prevention of stroke."