Genes Make the First Biological Pacemaker

Experts have crafted what they are calling a "biological pacemaker" by simply implanting modified genes into the cells of an irregularly beating heart. This minimally invasive procedure could potentially do away with physical pacemakers entirely, reducing the chance of infection or other complications.

Pacemakers are a wonder of modern medicine in their own right. They can regulate the heart long after the heart's natural rhythm - determined by a cluster of cells called the sinoatrial (SA) node - has been lost.

Electrical signals from modern pacemakers simulate the signals that would normally be sent from a functioning SA node. The signals work much like the call of a good coxswain on a rowing team, telling the heart exactly when to contract.

While an implantable pacemaker can make an excellent replacement 'coxswain of the heart,' it doesn't come without its faults. Unlike human cells, mechanical pacemakers do not easily recover from electric shock. What's worse, the leads that connect a pacemaker to the rest of the heart's upper chamber can often become infected, causing potentially life-threatening situations.

Last May, professionals managed to implant the first leadless pacemaker into the heart of a woman. However, cardiologists from the Cedars-Sinai Heart Institute suggest doing away with mechanical implants entirely. Genes, they say, can do the pacemaking.

"We have been able, for the first time, to create a biological pacemaker using minimally invasive methods and to show that the biological pacemaker supports the demands of daily life," Eduardo Marbán, director of the Cedars-Sinai Heart Institute, said in a recent statement.

Marbán and his team successfully "reprogrammed" several cells in the heart to function as a new SA node, setting a new a regular pace in laboratory pigs previously suffering from irregular heart rhythm.

The researchers accomplished this by inserting specific genetic information into the cells. Over a 14-day study, this insertion not only created a new SA node in malfunctioning hearts, but regular healthy heart beats persisted for the whole two weeks.

"Originally, we thought that biological pacemaker cells could be a temporary bridge therapy for patients who had an infection in the implanted pacemaker area," Marbán said. "These results show us that with more research, we might be able to develop a long-lasting biological treatment for patients."

Co-author Eugenio Cingolani added that with additional success, they may also consider the use of this type of genetic therapy on newborns suffering from irregular heart rhythms - as even modern pacemakers are far too large for their delicate hearts.

A study detailing these findings was published in Science Translational Medicine on July 16.