A new international study by the Carolinaska Institute and Columbia University, published in the journal Nature Communications, has found that the heart has a “mini-brain” that controls the heartbeat. The study was led by Konstantinos Abatzis, a principal investigator and doctoral student at the Department of Neurosciences at the Karolinska Institute in Sweden.

Originally from Thessaloniki, Constantine Abatzis studied at the Biology Department of the University of Crete and since 2016 he has been a research professor at the Karolinska Institute.

“This ‘mini-brain’ of the heart has a key role in maintaining and controlling the heartbeat, similar to that of the brain in terms of controlling rhythmic functions such as movement and breathing,” explains Konstantinos Ampatzis.

For a long time, the heart was thought to be controlled only by the autonomic nervous system, which carries commands from the brain. The heart’s neural network, located in the surface layers of the heart wall, was considered a simple structure that merely carried the brain’s signals. However, recent studies have revealed that its function is more complex. Scientists have found that the heart has its own complex nervous system, which plays a crucial role in regulating its rhythm.

A deeper understanding of this system, which is much more diverse and complex than we assume, may lead to new treatments for heart disease. The researchers identified several types of neurons in the heart with different functions, including a small group of neurons with pacemaker properties. This finding challenges the existing understanding of heartbeat control, which may have clinical implications.

“We were surprised by the complexity of the heart’s nervous system. A better understanding of this system may provide new insights into heart disease and contribute to the development of new treatments for diseases such as arrhythmias,” says Konstantinos Abatzis.

The research was carried out in zebrafish, an animal model whose heart rhythm shows significant similarities to that of humans, as well as to the overall function of the heart. The researchers were able to map the composition, organisation and function of neurons within the heart using methods such as single-cell RNA sequencing, anatomical studies and electrophysiological techniques.

“We plan to continue research on how the ‘brain’ of the heart interacts with our central brain to regulate heart functions under different conditions, such as exercise, stress or disease,” says Konstantinos Abatzis.

“Our goal is to identify new therapeutic targets by examining how disorders in the neural network of the heart contribute to various cardiac disorders,” concludes the Greek researcher.