WASHINGTON — Researchers have discovered that mutations to a particular gene can dramatically lower the risk for heart attack. Scientists are now trying to develop drugs that target the gene in the hopes of bringing down the high rate of heart disease.
Two papers published this week in the New England Journal of Medicine identify a gene called APOC3 in connection with the body's removal of triglycerides, a type of blood fat. Circulating triglycerides, if not eliminated from the body, stick to blood vessels and are stored in tissues in the hips and belly.
When elevated, triglycerides, or lipids, are thought to be a risk factor for heart disease. Approximately one in 150 people has mutations to the APOC3 gene that keep their triglyceride levels low, according to the findings of a new study.
A large investigation of 110,000 patient blood samples found those with the rare mutations had lower levels of triglyceride fats and a significantly reduced risk for the most common form of heart disease.
“We compared the heart attack rates of people who carried the mutations and those who didn’t, and found that people who carried the mutations and had the lower triglycerides had 40 percent lower risk for heart attack,” said Sekar Kathiresan, director of Preventive Cardiology at Massachusetts General Hospital and an associate researcher at the Broad Institute of Biomedical Research.
Kathiresan helped lead the study that identified four beneficial genetic mutations to the APOC3 protein.
The connection with elevated LDL - a blood fat commonly called bad cholesterol - and heart disease is well-known. Experts know less about the benefits of raising HDL, or a blood lipid called good cholesterol, as a hedge against heart attack, and the role triglycerides levels play in coronary artery disease.
The latest study of thousands of research subjects found elevated levels of good cholesterol were not protective, while low triglyceride levels appear to be.
With discovery of the four mutations, researchers now have a target to develop a drug to lower blood lipids, reducing the risk of heart attack.
“Given that these people are naturally protected, if you develop a medicine that mimics this, then your chances of it working in terms of reducing the risk of heart attack are quite great,” Kathiresan said.
Many people still have elevated triglycerides despite exercising, eating a low fat, low carbohydrate diet and taking statin drugs. An agent that targets APOC3 may further reduce blood fats, lowering the risk of heart attack, he said.