The role of high density lipoprotein (HDL) in protecting against heart disease has been confirmed by a University of Amsterdam cardiologist.
John Kastelein made his finding while examining a patient who was brought into emergency at an Amsterdam hospital after he had collapsed with a heart attack.
The 36-year-old man was tall and lean, non-smoking and physically fit.
The damage was so severe that seven of his arteries had to be bypassed.
"In young people, surgeons often use the mammary artery that runs parallel to the breastbone on both sides, to patch into the heart,'' he said.
"That artery never has atherosclerosis [blockages] so the surgeon was totally amazed to find both mammary artery walls had become diseased," he explained.
Investigations revealed the patient, Piet Snoek, had a gene mutation that blocked all production of HDL.
His case "completely convinced" Professor Kastelein that the protective effects of HDL were as significant a part of the heart disease story as the well-known damage wrought by low density lipoprotein "bad" cholesterol.
He set out to demonstrate a heresy: that raising cholesterol could help the heart, provided the cholesterol in question was HDL.
"Every manipulation that raises HDL in a mouse or a rabbit is beneficial," said Professor Kastelein, who will deliver a plenary address in Sydney on Monday at the International Symposium on Atherosclerosis.
Fifteen years later, Snoek is still alive. Professor Kastelein and colleagues have used drugs to completely eliminate LDL from his body, compensating for the absence of HDL.
"Heart disease is the result of the balance of these two," he said.
Several drug companies have begun synthesising HDL - which attaches to cells that mop up LDL, steering them into the circulation - following a heart attack.
"We have shown we can mobilise cholesterol from the arterial wall. We can move amounts of cholesterol that in my mind are very clinically significant," Professor Kastelein said.
The next step is to use heart scans to evaluate whether this reverses artery damage.
Philip Barter, of the Heart Research Institute in Sydney, said raising HDL had ''the potential to be as important on top of [cholesterol-lowering] statins as statins were on nothing".