Single Gene Injection Could Soon Replace Electronic Pacemakers to Cure Heart Diseases

Electronic pacemakers may soon be a thing of the past, with researchers from Cedars-Sinai Heart Institute in Los Angeles developing a new bio-pacemaker.

The human heart has its own natural pacemaker, called sinoatrial node. The sinoatrial node is no more than the size of a peppercorn. This sinoatrial node keeps the heart beating by generating electrical activity. It acts much like a metronome, keeping the rhythm of the heartbeat normal, i.e. 60 to 100 beats per minute when in normal state, and more when the body is physically active.

Sometimes, however, the sinoatrial node fails to keep the heartbeat at normal levels. In such cases, electronic pacemakers are used, which works on the same principles as that of the sinoatrial node, creating an electrical impulse to increase the rate of contraction and expansion of the heart.

However, according to the new study published in the Science Translational Medicine, there could be a new bio-pacemaker on the way, which could make the use of electronic pacemakers obsolete, in the near future.

"In essence, we create a new sinoatrial node in a part of the heart that ordinarily spreads impulse, but does not originate it," said Eduardo Marban, author of the study and researcher at the Cedars-Sinai Medical Center. "The newly created node then takes over as the functional pacemaker, bypassing the need for implanted electronics and hardware."

The researchers created two types of non-replicating viruses – one creates the transcription factor TBX-18 for the actual research, while the other creates a fluorescent green protein, which would be used as a control for the experiment. TBX-18 is a gene that creates pacemaker cells in the sinoatrial node, when human beings are inside their mother's womb.

For this experiment, pigs with a condition known as "complete heart block" were employed. This means that there was a disruption in the electronic signalling between the top and the bottom half of their hearts, which slowed down their heart rate considerably. Every pig was also given an electronic pacemaker, as a backup.

The pigs that were given TBX-18 viruses showed much better heartrate than the pigs who were given the control viruses. Also, these pigs relied much less on the backup electronic pacemakers, and showed much more metabolism than the other group of pigs. An adrenaline-like drug was also given to all of them. The TBX-18 pigs responded much better to this drug than the other pigs.

However, since this experiment was conducted only for a period of two weeks, experts have their doubts on whether TBX-18 could be a long-term replacement for its much-tried and tested electronic counterpart.

"We don't know what the long term durability is," Nikhil Munshi, Cardiac Researcher at UT Southwestern Medical Center, told PopMech. "Especially in a situation where a patient has to be treated with antibiotics, if they need an extended period of up to six weeks, let's say, i don't think the study answered whether that would be feasible for long-term antibiotic treatments."