Researchers have found a new way to take charge of an out-of-control heart. All it takes is a light touch — literally touching the heart with a pulse of visible light.
Your heart beats tens of thousands of times each day. Its pace may speed up or slow down as your activities change. Yet its rate remains fairly regular, thanks to electrical signals that travel as waves from cell to cell through the heart. Those waves spread in somewhat the same way that a wave ripples through a baseball stadium as fans stand up and sit down in a coordinated fashion.
But watch out if something goes wrong with the heart’s waves of activity.
A wave sometimes spirals back on itself, for example. It’s almost looks “like a dog chasing its own tail,” explains Gil Bub. As a biophysicist at the University of Oxford in England, he studies the physics of life functions, particularly those of the heart. Such spiral waves that cross back on themselves can make the heart beat too quickly. And that can be deadly.
Medicines or electrical devices can reset — or sometimes even take over — someone’s heartbeat. However, such approaches basically jolt the whole heart. Now, however, there’s a new method to fine tune the control of waves in that muscle that makes up your heart.
“What we’ve done is figure out a way to use light to control waves in a way that hadn’t been done before,” explains Bub. To do that, his group at Oxford worked with biomedical engineer Emilia Entcheva and her colleagues at Stony Brook University in New York.
Together, the researchers used a fairly new technology called optogenetics. Opto- refers to light. Genetics deals with the biological instructions in our cells. The technology uses light to either turn on or shut down genetically programmed actions in cells.
Until now, most people working in this field focused on the brain and nervous system. Among them is Keith Bonin, a physicist at Wake Forest University in Winston-Salem, N.C. He has used optogenetics to study brain cells called neurons. Electrical signals travel through these nerve cells and cause the release of chemicals that send messages to neighboring neurons.
Muscle cells in the heart also produce electrical signals. However, these signals spread from cell to cell in a different way — as waves. Working with heart-muscle cells, Bonin says, “is an interesting new application of the tools of optogenetics.”
