Israeli researchers use light beams to resynchronize irregular heartbeat of rats

Method may pave way to provide alternative to using electrodes into various parts of the heart.

By JUDY SIEGEL-ITZKOVICH
Updated: JUNE 24, 2015 00:08
A rat (photo credit: REUTERS)
A rat
(photo credit: REUTERS)
It is possible to resynchronize irregular heartbeats using a spotlight instead of a pacemaker, according to researchers at Haifa’s Technion- Israel Institute of Technology who published their findings in the journal Nature Biotechnology this week.
The study was led by Prof. Lior Gepstein of the Technion’s Rappaport Medical Faculty, who is also the chief of cardiology at Rambam Medical Center.
The Haifa team said that irregularities in the heartbeat, which involve the electrical conduction of the heart, can lead to a significant slowing down and lack of synchronization of the contraction of the muscles in the four chambers of the heart.
As this condition has negative implications such as weakness, dizziness, fainting, a worsening of cardiac sufficiency and even the risk of death, over the years various techniques have been developed for artificial intervention in the beating of the heart. The most acceptable means is the implantation of an electric pacemaker that corrects the arrhythmia using electrodes inserted into parts of the heart.
But there are many limitations, such as having to perform an invasive procedure to attach the pacemaker, the risk of infection, limitations on the number of electrical wires that are connected to the heart and their location, a decline in cardiac function due to a change in the electrical activation pattern, and significant problems in implanting pacemakers in children.
As a result, many researchers have been working on biological replacements for the electric pacemaker.
In the article, the optogenetic approach is discussed.
As a member of Gepstein’s lab, Dr. Udi Nussinovitch worked on the problem as part of his doctoral dissertation.
Nussinovitch now serves as a doctor and researcher in Rambam’s cardiology department.
Optogenetics are based on the use of proteins sensitive to light, such as the ion channel called ChR2 that is obtained from seaweed and not naturally found in the human body. The proteins are used to activate or suppress the electrical activity of excitable cells such as neurons or muscle cells after they are exposed to light.
Using optogenetic techniques has brought about a revolution in brain research, and the current study is the first instance of using light to resynchronize the heartbeat, Nussinovitch said.
In the experiment carried out on rats, the researchers aimed a blue spotlight toward the region of the heart that expresses the ChR2 protein.
They then showed the ability to repair the heartbeat by lighting up the heart tissue at a varied frequency. At a more advanced stage, the rats’ hearts were activated simultaneously at a number of different foci using light – and this brought about a significant improvement in the synchronization of the hearts’ chambers.
Gepstein noted that their work was primary research and that “to translate the approach to the clinical level” they would need to overcome several significant problems.
“We must improve the penetration of light into the tissue so that continuous expression of the protein is ensured over a period of years,” he said. “We also have to develop a unique pacemaker device that will supply the necessary light. But despite all this, the research shows the great potential in optogenetic techniques as a replacement for electric pacemakers and as a way to resynchronize the heart’s chambers in the event of cardio insufficiency.”