Gene “Toggle” Regenerates Injured Heart Cells

For the first time, researchers have transformed scar tissue that grows after a heart attack into regenerated heart muscle using microRNAs, according to new lab animal research. If validated in human studies, this finding could help prevent heart failure after a heart attack and applied to other types of tissue regeneration.

The study’s findings were reported online before print April 26, 2012, in Circulation Research, an American Heart Association journal. After a heart attack, heart muscle does not effortlessly regenerate and it accumulates scar tissue, comprised of cells called fibroblasts--increasing risk for heart failure.

“Researchers have tried various approaches, including the use of stem cells, to regenerate damaged heart muscle tissue,” said Victor J. Dzau, MD, the study’s senior author and a professor of medicine at Duke University Medical Center (Durham, NC, USA). “This is the first study to use microRNA, which are small molecules that control gene expression, to reprogram fibroblasts into heart muscle cells. We have not only shown evidence of this tissue regeneration in cell cultures, but also in mice.”

Using microRNA is simpler than many other tissue-regenerating approaches, according to Dr. Dzau, who is also chancellor for health affairs at Duke University. For example, stem cells are not easy to work with and have ethical issues surrounding their use, he noted. “This research represents a major advance in regenerative medicine overcoming the difficulties encountered with stem cells, and may be applied to other conditions of tissue damage such as stroke and spinal cord injury.”

Dr. Dzau’s team identified a combination of three microRNA types that convert fibroblasts to muscle cells. In the next phase of research, the researchers will assess whether microRNAs repair damaged hearts in larger animals and improve heart function. If those studies prove safe and effective, they will begin human studies. “If everything comes to fruition, I think we will see this as a therapy in the next decade,” Dr. Dzau said. “Conceivably, we’ll use it to regenerate hearts damaged by heart attacks, avoiding heart failure and saving lives.”

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Duke University Medical Center