A team of researchers in Shanghai has succeeded in developing a laboratory version that mimics the human heart's natural pacemaker, from a group of cells responsible for regulating the heartbeat.
Deep inside the right atrium of the heart, there is a very small area known as the "sinoatrial node," which is a very small group of cells responsible for controlling the heartbeat.
This node is often described as the "natural pacemaker" of the heart, as it generates electrical impulses that maintain the regularity and coordination of the heartbeat.
When this area functions properly, it receives signals from the nervous system to coordinate the contraction of the upper and lower chambers of the heart, ensuring proper blood flow throughout the body. If it malfunctions, the heartbeat may slow down significantly or stop momentarily, disrupting circulation and posing a life-threatening risk, potentially requiring the implantation of an artificial pacemaker.
What new discoveries have scientists made?
Researchers at advanced Chinese institutes, such as the Chinese Academy of Sciences and Fudan University, have turned to the use of human pluripotent stem cells, which are cells that can transform into any other tissue in the body.
Using these cells, they were able to grow a three-dimensional organoid of the sinoatrial node in the lab. This organoid is not just ordinary cells, but a self-pulsing replica that generates regular electrical signals, much like the activity of a natural pacemaker.
An organoid is a miniature, simplified version of a real organ, grown in a laboratory using stem cells.
To make the model more realistic, the team connected this organelle to an artificial neural network that resembles the neural plexus near the base of the heart, allowing them to recreate how the nervous system communicates with the pacemaker.
This step is the first of its kind in the laboratory, and opens the door to studying heart rhythm disorders more accurately, and developing future biological treatments that may reduce reliance on implanted electronic devices.
This development is significant because animal studies, particularly in mice, have failed to accurately replicate the mechanism of action of the human pacemaker. Furthermore, the human sinoatrial node is very small and located in a hard-to-reach area within the heart, making direct study in human tissue samples rare. Therefore, laboratory models have been the optimal solution.
Compared to natural tissue, the engineered organoid showed a high degree of similarity to human embryonic ganglion cells in terms of gene activity and responded correctly to heart rate-regulating drugs. This success paves the way for the potential use of implanted cells or organoids as biological pacemakers, an alternative to traditional electronic devices which, despite being in use for over 50 years, remain the most common choice for patients with serious heart rhythm disorders.
