- Biological pacemaker has a group of cells which produces specific electric stimuli when injected in certain regions of the heart.
- Human embryonic stem cells grown to cardiac cells helps originate heart beat when injected in the sinoatrial node.
Electric pacemakers can soon be replaced with biologic pacemakers which were developed using sinotrial (SA) node pacemaker cells. These cardiac cells were grown from human embryonic stem cells.
A biological pacemaker is one or more types of cellular components that, when "implanted or injected into certain regions of the heart," produce specific electrical stimuli that mimic that of the body's natural pacemaker cells. The biological pacemaker is intended as an alternative to the artificial cardiac pacemaker that's been in human use since the late 1950s.
‘SA node pacemaker cells are responsible for initiation of the electrical signal leading to the contraction of the heart. A pacemaker comes into play when there is a dysfunction in the sino atrial node.’
A team of scientists from Israel and Canada have developed a biological pacemaker that overcomes many of the limitations of electrical pacemakers. The breakthrough findings could pave the way for an "assembly line" for an unlimited reservoir of pacemaker cells to treat patients with heart rhythm problems.
The SA node is the natural pacemaker of the heart and is comprised of a group of dedicated heart cells - SA node pacemaker cells - responsible for initiation of the electrical signal leading to the contraction of the heart.
A dysfunction in their activity results in slow beating rate that could disrupt cardiac function and lead to weakness, dizziness, fainting, heart failure, and even death. Such dysfunction requires the implantation of an artificial electronic pacemaker to correct the dysfunction of the natural pacemaker mechanism using electrodes inserted into various areas of the heart.
But such electrical pacemakers have a myriad of limitations, including an invasive surgical procedure, danger of infection, a lack of hormonal sensitivity and a limited duration of activity (due to limited battery life). An electrical pacemaker does not adapt itself to the gradual increase in cardiac volume when it comes to treating children, whose hearts are still growing.
One of the most promising future alternatives to electrical pacemakers is the biological pacemaker strategy, based on the use of cells that are functionally similar to natural pacemaker cells.
"It is an effective and promising alternative to natural pacemaker cells in the event of their dysfunction. This development is significant both in terms of research - because it will enable scientists to study the heart in new ways, and in practical terms - since we are presenting an assembly line here for an unlimited reservoir of pacemaker cells to treat patients with heart rhythm problems."
To demonstrate the potential future clinical use of the cells as biological pacemakers, experiments were conducted in the Gepstein laboratory on rats. Pacemaker cell transplants restored normal heart rhythm in 6 of the 7 rats that were tested.
"We have previously demonstrated the concept of biological pacemakers, but until now the cells we used contained a mixture of pacemaker cells with other heart cells," said Prof. Gepstein. "Together with our Canadian partners, we present a method for producing a population of pure pacemaker cells and give proof that they work well as a substitute for natural pacemaker cells that have been damaged."
- Professor Lior Gepstein et al., Canadian-Israeli Development: A New Biological Pacemaker, Nature Biotechnology (2016).