Sleep disturbance cause in cardiac disease identified

Around one third of people with heart disease suffer from sleep problems. In a paper published in the journal Science, a team at the Technical University of Munich (TUM) shows that heart diseases affect the production of the sleep hormone melatonin in the pineal gland. The link between the two organs is a ganglion in the neck region. The study demonstrates a previously unknown role of ganglia and points to possible treatments.

The team discovered that macrophages accumulate in the cervical ganglion of mice with heart disease. These macrophages cause inflammation and scarring in the ganglion and the destruction of nerve cells. In mice, as in humans, long fibers extending from these nerve cells, called axons, lead to the pineal gland. At advanced stages of disease, there was a substantial decrease in the number of axons connecting the gland to the nervous system. There was less melatonin in the bodies of the animals and their day/night rhythm was disrupted.

Comparable organic effects were seen in humans. The team investigated the pineal glands in nine heart patients. Compared to the control group, significantly fewer axons were found. As with the mice, the superior cervical ganglion in the humans with heart disease showed scarring and was noticeably enlarged.

The researchers assume that the negative effects of the dead axons become permanent at an advanced stage.

Ref: K.A. Ziegler, A. Ahles, A. Dueck, D. Esfandyari, P. Pichler, K. Weber, S. Kotschi, A. Bartelt, I. Sinicina, M. Graw, H. Leonhardt, L. Weckbach, S. Massberg, M. Schifferer, M. Simons, L. Hoeher, J. Luo, A. Ertürk, G.G. Schiattarella, Y. Sassi, T. Misgeld, S. Engelhardt. “Immune-mediated denervation of the pineal gland underlies sleep disturbance in cardiac disease”. Science (2023). DOI: 10.1126/science.abn6366