READING, United Kingdom — An antioxidant drug that doctors already know is safe for humans may help reverse a condition which leads to heart attacks and strokes for many patients. Researchers at the University of Reading say cysteamine can “switch off” the damaging process of atherosclerosis, thereby preventing heart damage due to blood clots.
Atherosclerosis is the buildup of fatty deposits along the artery walls. When LDL cholesterol (or “bad cholesterol”) oxidizes and forms plaques in the arteries, inflammation increases which can allow the plaque to rupture and cause a blood clot. From there, blood clots can block the flow of blood vessels to the heart (causing a heart attack) or to the brain (causing a stroke).
In previous studies, researchers have discovered that “bad” cholesterol can oxidize in small acidic “bags” called lysosomes inside the immune cells. The new report reveals that cysteamine reverses this process within the artery walls.
How does cysteamine work?
Study authors say the antioxidant drug accumulates in the lysosomes and prevents cholesterol from oxidizing. Cysteamine is already a proven drug which doctors prescribe for the rare lysosomal disease called cystinosis.
In trials with mice suffering from atherosclerosis, cysteamine produced a 32 to 56-percent reduction in the size of plaques in the arteries. Study authors notes the size of the drop was bigger depending on which part of the aorta (the body’s largest artery) they measured.
The drug also lowered the amount of oxidized fat by 73 percent and improved the stability of areas susceptible to atherosclerosis. Moreover, cysteamine lowered the proportion of inflammatory white blood cells by 55 percent and increased the surface area composed of smooth muscle cells by 85 percent. All of these changes, researchers say, contribute to preventing plaque buildups that can cause a blood clot.
Antioxidant drugs typically have a poor success rate
Past trials with other antioxidant drugs, which had promising results in mice, ultimately proved to be disappointing when doctors tested them in humans. The Reading team is hoping this new contender can beat those odds.
“The potential in this drug to protect against heart attacks and strokes and ultimately save lives superseded our expectations. We hoped it would cause plaques to grow at a slower pace, but we were amazed to find it reversed the process,” says Biomedical Sciences Professor David Leake in a university release.
“Cysteamine would offer an entirely new way of treating atherosclerosis. We now want to look at the most efficient way to give this drug to patients, and hope that it can be taken to clinical trials in the next few years.”
“Heart attacks and strokes threaten the lives of people too often,” adds Professor James Leiper, Associate Medical Director at the British Heart Foundation.
“If this antioxidant drug can show the same promising effects in humans, then it could offer a lifeline to thousands of people in the future.”
The findings appear in the Journal of the American Heart Association.