How to mend a broken heart

Heart disease and electronic pacemakers may be a thing of the past sooner than expected. In a novel use of gene therapy, preliminary research suggests damaged heart tissue can be brought back to life with a dose of DNA.

Heart disease is a major cause of death across the country, killing 20 percent of all Australians. When heart muscle is damaged, during a heart attack for example, scar tissue forms, disrupting the heart’s electrical system weakening the heart. If these invading scar cells can be reprogrammed to behave like heart muscle cells, it may mean a totally new treatment for this costly and debilitating condition.

This exciting research, conducted by PhD graduate and cardiologist Dr Eddy Kizana at the Children’s Medical Research Institute (CMRI) in collaboration with Westmead Hospital, The Children’s Hospital Westmead and the University of Sydney, will be published in the leading journal ‘Circulation’. Dr Kizana was supported by a Fellowship from the National Heart Foundation of Australia.

These early experiments involved adding two extra genes to the cells. Dr Ian Alexander, Head of Gene Therapy at the CMRI explains, “Adding the genes is like reprogramming the cells; the first gene programs the cell to be excitable like a muscle cell, the second gene allows the cells to communicate with each other – essential for the electrical pulse of the heart to be passed on. The scar cells take on totally new characteristics.”

Although an electronic pacemaker can be a good remedy for this type of heart disease, the device does eventually wear out. Relatively young people in particular may face several operations and hospital visits to replace the worn out machinery. Dr Alexander adds, “With extensive research it may be that gene therapy can give a patient’s own cells the capacity to be repaired for life. More work must be done, but our studies on cells grown in the laboratory show that this may be an exciting new application for gene therapy.”

Adult heart disease patients may not be the only ones to benefit in years to come. “This technique could prove to be beneficial not only for heart disease patients but in many conditions where the heart fails to beat correctly, including congenital diseases like heart block in children,” says Dr Alexander.