They find a link between sleep disturbances and heart problems

Scientists from the Technical University of Munich revealed the relationship between heart disease and rest problems and stated that these pathologies affect the production of melatonin.

About a third of people with heart disease -which includes different diseases, such as heart attacks- suffer from sleep problems. However, it was unknown why it happened. Now, a team of researchers from Germany provided an answer.

In an article published in the journal Science, scientists from the Technical University of Munich (TUM) in Germany showed that heart disease affects the production of the sleep hormone melatonin in the pineal gland.

The link between the two organs is a ganglion located in the neck region. The study then suggested a hitherto unknown role of the ganglia and opens a door to the development of possible treatments.

It has long been known that melatonin levels can decrease in patients with heart muscle diseases, for example after having had a heart attack. In general, that has been considered another example of how a heart condition acts systemically throughout the body.

The German team in which Stefan Engelhardt, Professor of Pharmacology and Toxicology at TUM, and Dr. Karin Ziegler, who was the first author of the paper, collaborate, have now proven that there is a direct cause behind sleep disorders in people suffering from medical conditions. cardiac.

"In our work we show that heart muscle problems affect an organ that at first glance would seem to have no direct relationship to it," said Stefan Engelhardt.

Melatonin is produced in the pineal gland, located within the brain. Like the heart, it is controlled by the autonomic nervous system, which regulates involuntary processes in the body. Related nerves originate from ganglia, among other places. Especially important for the heart and the pineal gland is the superior cervical ganglion.

“To understand our results, let's imagine the ganglion as an electrical switch box. In a patient suffering from sleep disturbances after heart disease, you might think that a problem with one cable causes a fire in the breaker box and then spreads to another cable,” Engelhardt said.

The team discovered that macrophages - cells that feed on dead cells - accumulate in the cervical ganglion of mice with heart disease, causing inflammation and scarring in the ganglion and destruction of nerve cells.

In rodents, as in humans, long fibers that extend from these nerve cells, called axons, lead to the pineal gland. In advanced stages of the disease, a substantial decrease in the number of axons connecting the gland to the nervous system was observed. There was even less melatonin in the animals' bodies and their day/night rhythm was altered.

Comparable organic effects were observed in humans. The team investigated the pineal glands of nine heart patients. Compared to the control group, significantly fewer axons were found. As in mice, the upper cervical node of humans with heart disease was scarred and markedly enlarged.

Engelhardt believes that the nodes could also become important from a diagnostic point of view. Since all of the cervical nodes in the cardiac patients they examined were significantly enlarged, the researchers believe this could be an indicator of heart failure.

The size of the node can be easily checked with a conventional ultrasound machine. If the results are confirmed in subsequent studies, it might be advisable to order more exhaustive controls of the heart when the node is detected to be enlarged. (DIB)

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