Researchers Convert Heart Muscle Cells Into Pacemakers by Inserting a Gene

Researchers have found a way to turn ordinary heart muscle cells into pacemaker cells just by inserting a gene. The research can lead to new ways to help people whose hearts start beating irregularly.

Researchers from Cedars-Sinai Heart Institute converted normal heart cells into cells that generate rhythm in the heart by injecting a single gene (Tbx18) into the cells. A genetically modified virus was used to inject the gene in the cells.

"Although we and others have created primitive biological pacemakers before, this study is the first to show that a single gene can direct the conversion of heart muscle cells to genuine pacemaker cells. The new cells generated electrical impulses spontaneously and were indistinguishable from native pacemaker cells," said Hee Cheol Cho, PhD., a Heart Institute research scientist.

Pacemaker cells generate rhythmic muscle contraction by generating electrical activity that spreads to other cells. When these cells get damaged, the heartbeats go haywire; and people suffering from this condition need to undergo a surgery, where an electronic pacemaker placed in the body restores the heartbeat.

Heartbeats begin in the sinoatrial node (SAN) of the heart's right upper chamber, where pacemaker cells are present. Less than 10,000 of the one billion heart cells are pacemakers.

Pacemaker cells are also called as SAN cells. Researchers reprogrammed normal heart cells into SAN cells by the Tbx18 gene. These newly created pacemaker cells or iSAN (induced-SAN) had all features of the regular pacemaker cells.

Tests on guinea pigs showed that the new pacemaker cells worked just like the old ones in creating the heartbeat.

If further research confirms the study's finding then we could see a revolution in way irregular heartbeats are fixed by using a pacemaker.

Researchers said that one of the ways to use the therapy would be to inject a virus carrying the gene in the heart, creating a new cluster of pacemaker cells. Another way would be to create pacemaker cells in the laboratory and then transplant these into the patient's heart.

The study is published in the journal Nature Biotechnology.