Fat cells help to repair injured nerves

Our body is criss-crossed by millions of nerve fibres that transmit information. For example, muscles can be controlled or sensory impressions can be perceived. However, peripheral nerves, such as the nerves in our arms and legs, are often damaged as a result of acute injuries, such as accidents. As a result, those affected suffer from a loss of muscle strength or sensory problems such as numbness. In principle, peripheral nerves have a high potential for regeneration. However, complete restoration of nerve function is still rare for reasons that are not yet sufficiently understood.

When a nerve is crushed or severed, the individual nerve fibres that are affected by the damage initially die. In principle, however, they have the ability to grow back and fully regenerate. They are dependent on the Schwann cells surrounding the nerve fibres. These do not die after a nerve injury, but are responsible for coordinating the breakdown and regrowth of the nerve fibres to their original areas. Schwann cells therefore play a key role in the repair process. Until now, however, it was unknown how these cells cope with the enormous metabolic load associated with the degradation and reconstruction of nerve tissue. Scientists at Leipzig University Medicine have now discovered that Schwann cells are decisively supported in nerve repair by the fatty tissue that surrounds the nerves in the body. With the help of genetically altered mice, they were able to prove that the messenger substance leptin plays a key role in this process.

Leptin is primarily produced by cells in adipose tissue and has previously been known in the nutritional context for its appetite-regulating effect. Surprisingly, the current research project showed that the leptin signalling effect is also an important factor in the repair of injured nerves by Schwann cells. The leptin of fat cells stimulates the energy balance of regenerating Schwann cells by stimulating their mitochondria," explains Dr Robert Fledrich from the Institute of Anatomy at the University of Leipzig, one of the two study leaders.

„At the same time, the mitochondria of the Schwann cells use parts of the damaged nerve tissue as an energy substrate so that successful regeneration can take place," adds Prof Dr Ruth Stassart from the Paul Flechsig Institute of Neuropathology at Leipzig University Hospital, co-leader of the study. The metabolism of the Schwann cells is thus optimised for nerve regeneration and thus significantly facilitates the restoration of the original nerve function, as the two scientists explain.

The communication between fat cells and Schwann cells could potentially open up new therapeutic options that positively influence the metabolism of repair cells in nerve damage. The researchers involved hope that the new findings will help to improve the usually poor regeneration of damaged nerves in humans in the future.

Press release by "idw - Informationsdienst Wissenschaft" from 28 November 2023