Stem cells repair injured heart

Researchers have successfully grown heart muscle cells in sufficient quantities to repair the damaged heart of a primate, taking an important step towards cardiac muscle cell transplantation becoming a viable clinical therapy for heart failure.

The collaborative work involved physician-scientist Dr James Chong at Sydney’s Westmead Millennium Institute for Medical Research and Professor Charles Murry and his team at the University of Washington.

The researchers produced and delivered 1 billion human embryonic stem cell-derived cardiomyocytes into macaque hearts following heart failure. Injecting the cells into the animals’ damaged heart tissue resulted in large-scale re-muscularisation and regeneration of the failing organ.

The animal subjects were observed for up to three months - a much longer period than previously demonstrated in a clinically relevant model. The results showed that the new heart muscle cells engrafted and achieved electromechanical coupling with the original host heart.

Dr Chong said the research is a significant breakthrough in using the new technology of regenerative medicine for human patients with heart disease.

“Chronic heart disease rates in Australia and worldwide are reaching epidemic proportions and one in two people with advanced-stage heart failure will die within one year of diagnosis,” Dr Chong said.

“While adult stem cells are already being used in clinical trials on heart attack sufferers, that method has so far demonstrated only modest benefits. By using pluripotent stem cells, which have superior plasticity, we were able to grow and graft stem cell-derived heart muscle in significantly larger numbers than previously possible.”

Dr Chong said the technology is getting closer to growing heart muscle cells on a scale large enough to treat human patients, with the human stem cell-derived heart muscle grafts able to be produced on a clinical scale and then cryopreserved with good viability in preparation for transplantation.

“This technology brings us one step closer to the clinic and a possible future cure for heart failure,” he said.

Furthermore, the study showed for the first time that in-growth of blood vessels from the host heart was responsible for supplying the grafted heart muscle with nutrients.

“The stem cell-derived heart muscle was able to replace damaged and dead heart tissue by up to 40%,” Dr Chong said.

“These studies support the further use of human stem cell-derived heart muscle for heart regeneration which could one day be a cure for heart failure and replace the need for heart transplantation.”

Dr Chong and a team at WMI are seeking additional funding to continue large animal modelling tests at Westmead in the hope of moving to human clinical trials in a few years.

The work was published in Nature.