Professor Cooper's team has found that it also, unexpectedly, repairs the hearts of diabetic rats and possibly humans, suggesting that the high blood glucose levels in diabetics somehow trigger a buildup of copper in the heart.
Heart disease and strokes kill more than two-thirds of the world's 194 million diabetics.
"We have found that there is an abnormality of copper metabolism in diabetes and that, when you direct therapy at that abnormality, you can cause regeneration of the heart," Professor Cooper said.
The National Heart Foundation's medical director, Professor Norman Sharpe, said: "It has been assumed since the beginning of time that heart muscle will not regenerate. This work refutes that."
But diabetes specialist Professor Bob Elliott cautioned that Professor Cooper's findings in human patients were "a marginal call" as yet, and his findings in rats would not necessarily translate into humans.
"It will cause a flurry of activity, and quite rightly so," Professor Elliott said. "It gives us a new line for people to chase up."
Professor Cooper, a founder of San Diego-based Amylin Pharmaceuticals early in his career, is now chief executive of Protemix Corporation, which is based in his laboratory at Auckland University.
The company raised $20 million last year to fund its phase-two human trials of trientine, which it has patented and renamed "Laszarin" for its use in diabetics with heart disease.
A memorandum prepared for investors last year said Laszarin "has the potential to exceed annual sales of US$1.2 billion [$1.85 billion] after five years".
The research has found that diabetic rats, whose hearts are enlarged by 67 per cent in three months, have high levels of copper in their urine.
Treatment with trientine extracted the excess copper, shrank the size of the heart to only 46 per cent above normal, and cut the level of stiff collagen in the rats' hearts from 67 per cent above normal to a mere 15 per cent.
An initial trial with 15 human diabetics in South Auckland found that trientine shrank people's swollen hearts by 5 per cent in six months, while another 15 who were not given the drug saw their hearts keep swelling by a further 3 per cent.
The company now plans a phase 2B trial of 90 patients in Auckland, Christchurch and Melbourne and hopes to start the final phase-three trials in Australasia, the US and possibly Europe and Japan late next year.
Professor Cooper believes the drug will only have its full effect in humans after treatment for two to two and a half years.
However, Professor Elliott warned that prolonged trientine treatment for other diseases had been shown to cut copper levels so much that it actually triggered heart failure, rather than preventing it.
He said the finding that the hearts of untreated human diabetics swelled by 3 per cent in six months showed that the measurements, using magnetic resonance imaging, had roughly a 3 per cent margin of error. It was "highly unlikely" that anyone's heart would actually swell so quickly.
"That would be 6 per cent a year. At that rate we'd have every diabetic dead within quite a short time."
Diabetes danger
* High blood glucose levels in diabetics trigger a buildup of copper in the heart.
* Heart disease and strokes kill nearly 130 million of the world's diabetics.
Cooper, Phillips, Choong, Leonard et al:
Regeneration of the Heart in Diabetes by Selective Copper Chelation
Herald Feature: Health
Related information and links
