High Lipoprotein Levels Can Cause Heart Disease

Dec. 24 -- WEDNESDAY, Dec. 23 (HealthDay News) -- A genetic study proves that high blood levels of the fat-carrying molecule called lipoprotein(a) can cause heart disease.

"The case for lipoprotein(a) as a direct cause of coronary artery disease is now firm," said Martin Farrall, a professor of cardiovascular genetics at the University of Oxford in England and senior author of a report in the Dec. 24 issue of the New England Journal of Medicine.

Elevated blood levels of LPA, as it is often abbreviated, have been linked to an increased risk of heart disease and other cardiovascular problems for decades, but the evidence has not been definitive. So while an elevated low-density lipoprotein (LDL) cholesterol level remains the most clearly established indicator of coronary risk, "our paper, by genetic research, shows that LPA plays an important role as well," Farrall said.

"Our results will not perhaps surprise some researchers, but the scale of this project and confidence in our results mean that we can move forward to study the details of LPA and coronary risk," he added.

It is a pivotal finding, said Dr. Sekar Kathiresan, director of preventive cardiology at Massachusetts General Hospital, who wrote an accompanying editorial. "Many things in medicine are associated with an increased risk of heart attack. Almost all of these associations are not of a causal nature. This brings LPA into the domain of causal factors. And if it is causal, that gives hope that reducing it can reduce the risk of heart attack," he said. "

"We are now honing in on a potential therapeutic target," Kathiresan stated.

LPA is a member of the family of molecules that carry LDL cholesterol, the "bad" kind that clogs arteries, in the blood. The most common such molecule is lipoprotein(b), which consists of LDL with one protein attached. LPA is different because it has an additional protein attached.

The study done by Farrall and his colleagues looked in exquisite detail at the genetic makeup of 3,145 people with coronary artery disease and 3,352 free of coronary disease. The study of more than 48,000 variants of 2,100 genes found that two variants affecting LPA levels were strongly associated with coronary disease.