A vaccine developed by University of New Mexico researchers has shown it can significantly reduce cholesterol levels in animals, offering the promise of an affordable treatment to prevent heart disease, according to a new study.
The vaccine could offer a lower-cost alternative to drugs now used to treat people with dangerously high levels of LDL cholesterol, said Bryce Chackerian, a UNM professor of molecular genetics and microbiology and co-author of the study.
The study will be published this week in the journal Vaccine. The vaccine prompts the body’s immune system to attack a protein that prevents cells from absorbing low-density lipoprotein cholesterol, often called “bad cholesterol,” that can collect in the walls of blood vessels, increasing the risk of heart disease.
If cells can’t metabolize LDL cholesterol, the artery-clogging substance remains in the bloodstream where it can cause damage, Chackerian said.
The work stems from the discovery a decade ago that people who lack a protein called PCSK9 have low LDL cholesterol levels and low rates of heart disease, he said. The discovery has led to a new class of drugs called PCSK9 inhibitors, now used mainly by people with extremely high cholesterol levels.
“The thing that makes these PCSK9 inhibitors so remarkable is that, in combination with statins, they are seeing reductions (of LDL cholesterol) on the order of 50 percent,” he said. “So it’s just a spectacular reduction in LDL cholesterol.”
Statins are an older type of cholesterol-lowering drugs that typically reduce LDL levels by 10 to 20 percent.
But the new drugs are expensive, costing patients up to $12,000 a year, and requiring frequent injections, the study said.
Treating everyone who has an inherited and dangerous type of high cholesterol would cost an estimate $16 billion a year in the U.S. alone, it estimates.
Researchers hope that a cheaper, long-lasting vaccine could provide the same benefit by training the body’s immune system to recognize PCSK9 as a dangerous intruder, even though the protein is manufactured by the body.
“We basically trick the immune system into thinking that this protein is bad,” Chackerian said. “We take little pieces of this PCSK9 protein and we display them on the surface of a virus-like particle.”
The artificial virus, though harmless, causes the immune system to arm itself against PCSK9 and neutralize or destroy it, he said.
The vaccine led to a 50 percent reduction in LDL cholesterol in tests on animals, the study found.
The work continues UNM’s efforts to design vaccines that attack specific targets associated with diseases such as Alzheimer’s disease, rheumatoid arthritis and Crohn’s disease.
The next step will be designing larger animal studies and, ultimately, convincing federal regulators that the vaccine is safe and effective.
“It looks very encouraging that targeting PCSK9 is going to be safe,” Chackerian said. “In my opinion, this PCSK9 protein is one of the most promising targets we’ve gone after.”