Scar tissue turned into heart muscle without using stem cells

Updated: Apr 27, 2012, 19:13 PM IST

London: In a pioneering experiment, scientists have turned scar tissue, that forms after a heart attack, into heart muscles without using stem cells.

An international team, led by Duke University Medical Center, has, in fact, used a new process which eliminates the need for stem cell transplant -- molecules called microRNAs to trigger the cardiac tissue conversion in a laboratory dish.

And, for the first time, in a living mouse, the scientists demonstrated the potential of a simpler process for tissue regeneration, the `Circulation Research` journal said.

If additional studies confirm the approach in human cells, it could lead to a new way for treating millions of people worldwide who suffer heart failure, which is often caused by scar tissue that develops after a heart attack.

"This is a significant finding with many therapeutic implications. If you can do this in the heart, you can do it in the brain, the kidneys, and other tissues. This is a whole new way of regenerating tissue," Victor J Dzau, who led the team, said in a release.

To initiate the regeneration, the scientists used microRNAs, which are molecules that serve as master regulators controlling the activity of multiple genes. Tailored in a specific combination, the microRNAs were delivered into scar tissue cells called fibroblasts, which develop after a heart attack and impair the organ`s ability to pump blood.

Once deployed, the microRNAs reprogrammed fibroblasts to become cells resembling the cardiomyocytes that make up heart muscle. The team not only proved this concept in the laboratory, but also demonstrated that the cell conversion could occur inside the body of a mouse -- a major requirement for regenerative medicine to become a potential therapy.

"This is one of the exciting things about our study. We were able to achieve this tissue conversion in the heart with these microRNAs, which may be more practical for direct delivery into cells and allow for possible development of therapies without using genetic methods or transplantation of stem cells," said Prof Maria Mirotsou, a team member.