Increasing the levels of a newly-identified protein that helps prevent arteries from clogging may reduce the risk of heart attacks or strokes, according to a new study. As men and women grow older, their chances for coronary heart disease also increases, researchers said. Atherosclerosis is a condition in which plaque builds up inside the arteries, which can lead to serious problems, including heart attacks, strokes or even death. Scientists at the University of Missouri (MU) in the US have found that the protein Insulin-like Growth Factor-1 (IGF-1), naturally found in high levels among adolescents, can help prevent arteries from clogging. Increasing atherosclerosis patients' levels of the protein could reduce the amount of plaque buildup in their arteries, lowering their risk of heart disease, researchers said. "The body already works to remove plaque from arteries through certain types of white blood cells called macrophages," said Yusuke Higashi, assistant research professor at the MU School of Medicine. "However, as we age, macrophages are not able to remove plaque from the arteries as easily," said Higashi. "Our findings suggest that increasing IGF-1 in macrophages could be the basis for new approaches to reduce clogged arteries and promote plaque stability in ageing populations," he said. In a previous study, researchers had examined the arteries of mice fed a high-fat diet for eight weeks. IGF-1 was administered to one group of mice. They found that the arteries of mice with higher levels of IGF-1 had significantly less plaque than mice that did not receive the protein. Since the macrophage is a key player in the development of atherosclerosis, the researchers decided to investigate potential anti-atherosclerosis effects of IGF-1 in macrophages. "Our current study is one of the first ever to examine a link between IGF-1 and macrophages in relation to vascular disease," said Patrice Delafontaine, Dean of the MU School of Medicine. Also Read: New protein can help treat cancer, other diseases "We examined mice whose macrophages were unresponsive to IGF-1 and found that their arteries have more plaque buildup than normal mice," Delafontaine said. Also Read: Protein that swallow up, quarantine Zika virus identified "These results are consistent with the growing body of evidence that IGF-1 helps prevent plaque formation in the arteries," he said. The researchers also found that the lack of IGF-1 action in macrophages changed the composition of the plaque, weakening its strength and making it more likely to rupture and cause a heart attack.