By now, you likely know what a pacemaker is. It’s a small device that’s placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate. Electronic cardiac pacemakers and defibrillators have become successful and accepted ways to treat arrhythmia. But these devices can experience some problems: metal leads can short; batteries can run out; and magnetic fields can cause interference. Now scientists think they have found a new way of controlling heart function.
This latest health breakthrough involves a new technique that stimulates heart muscle cells with low-energy light. This creates the possibility for a future light-controlled pacemaker.
In the new study, researchers built on knowledge discovered in previous research. Several years ago, investigators determined that brain cells could be stimulated using light if they were genetically altered to produce a light-sensitive protein called “channelrhodopsin 2” (or ChR2). Fast forward to the recent study: scientists created cells expressing the ChR2 protein and coupled them with heart muscle cells from animals, creating heart tissue stimulated by light. They found that light-triggered heart muscle contractions and electrical waves were indistinguishable from electrically triggered waves.
What makes this health news particularly important?
Rather than directly modifying heart cells, the researchers coupled donor cells optimized for light responsiveness with the heart cells. The new technique uses much lower energy than in prior studies and doesn’t require the use of viruses or the introduction of genes from other organisms into heart cells. Instead, cells from a person’s bone marrow or skin can be cultured and modified to respond to light, reducing the possibility that the immune system will reject the light-sensitive cells.
The research team states that their method of non-viral cell delivery may overcome some hurdles on the way to potential clinical use by harvesting cells from the patient, making them light-responsive and using them as donor cells in the same patient.
This approach may someday improve pacemakers and defibrillators and become the alternative therapy for arrhythmia. Instead of metal leads, a light-controlled pacemaker would use biocompatible, flexible plastic optic fibers. Another bonus over current electronic pacemakers is that a light-based system might require only one-tenth the energy, meaning that a battery could last 50 years rather than five!