Heart tissue breakthrough

In a world first, local doctors have successfully grown new beating heart tissue in rats.

And the process could be used for people within a decade.

The heart tissue beats spontaneously with its own rhythm, which can be altered with a pacemaker or cardiac drugs.

It could be used to repair heart attack damage and other life-threatening ailments, and is the first step to creating organs to replace diseased and injured body parts.

The ground-breaking tissue-engineering technique uses a patient's own heart cells to grow new tissue in a special chamber implanted in the patient's own body.

This eliminates the risk of tissue rejection that occurs when tissue from another person is implanted.

Prof Wayne Morrison, who led a team of scientists from the Bernard O'Brien Institute of Microsurgery, said the development had the potential to revolutionise the treatment of heart disease.

"This is a major breakthrough for Australian medical science," he said.

"It's got a long way to go, but you can think of the possibilities of growing living tissue: taking the patient's cells and growing inside their own body living tissue that can be used to repair their own organs," he said.

The ultimate aim is to grow entire organs, but tissue "patches" could be used to repair dead heart tissue or to repair congenital defects.

"The capacity to create organs has huge ramifications for the thousands of people worldwide whose survival depends on transplants -- especially heart patients," Prof Morrison said.

Cardiovascular disease kills one Australian every 10 minutes and more than 100 Australians are waiting for a heart transplant. The average wait is more than three years.

Prof Morrison said the new tissue could also be wrapped around the aorta as a secondary pump to help a weakened heart.

The key to the breakthrough is the small chamber implanted in the patient, in which the tissue is grown. Scientists at the institute developed it and have patented it.

It allows cells to grow in three dimensions rather than on a flat dish, allowing them to behave as they would naturally.

Doctors removed heart cells from a rat and cultured them in the lab.

Microsurgeons then implanted the chamber in the rat and a loop of blood vessel in the chamber.

The heart cells were mixed with a jelly-like substance known as a matrix or scaffold, and put in the chamber on and around the blood vessel. The lid was put on the chamber and left for four weeks.

The blood vessel almost immediately began to sprout new capillaries that expanded through the cells throughout the chamber to form beating heart tissue.

Prof Morrison said he was very excited when he saw beating tissue.

He said it would be 5-10 years before the technique could be used in humans. Similar techniques could create other tissue types.

"We have been able to make breast tissue, fat, muscle, pancreas tissue that secretes insulin, and thymus tissue that may have implications for immunology," he said.

The institute collaborated with three departments of the University of Melbourne: surgery and medicine, at St Vincent's Hospital, and chemical and biomolecular engineering.

Treasurer Peter Costello officially announced the results yesterday.

"This is something I think will have the capability to improve the lives of many Australians," Mr Costello said.

The Federal Government provided more than $300,000 to support the start of the work in 2001.

"This is an area where Australia leads the world," Mr Costello said.

"The work of the institute is truly amazing."