A matter of nerves – progress in the field of neuroregeneration

Nerves run through our entire body and influence how we feel and move in the world. When a nerve is damaged, the consequences are immediate and often very far-reaching: from pain and sensory disturbances to the loss of function of entire limbs. What is damaged in a few seconds often determines the life of patients for a long time to come.

In Europe, around 300,000 people are affected by peripheral nerve injury every year, mostly as a result of an accident. Many of those affected are young adults. Due to the long rehabilitation phases, these injuries are associated with particularly high costs for the social system. But for the patients it is about more than just getting back to work: their entire quality of life depends on the success of the therapies.

The proverbial silk thread has a completely different meaning at LBI Trauma: a sub-project of the Neuroregeneration Group headed by Dr David Hercher deals with the development of novel nerve guidance splints made of silk.

If tissue is lost when a peripheral nerve – i.e. a nerve away from the central nervous system – is injured, a surgical intervention is necessary to restore the continuity of the nerve. In routine clinical practice, a nerve graft is taken from elsewhere for this purpose and serves as a bridge. However, this is accompanied by the loss of sensitivity of the area where the “donor nerve” was taken. In addition, the number of possible donor nerves is very limited. The need for clinical alternatives is great. One such alternative is bridging by means of an artificially produced nerve guide, a so-called conduit. At the LBI Trauma, in cooperation with the FH Technikum Vienna, a new type of conduit made of silk was developed. It has the necessary physical and biological properties to support the regeneration of a nerve. The silk conduit is already being used successfully in preclinical studies and is constantly being further developed. Accordingly, for instance, work is being done on adding growth factors to further support regeneration.

Research into the nervous system and its functional regeneration has developed at an almost breakneck speed in recent years. Nevertheless, individual aspects remain virtually unexplored, such as the structure and function of the lymphatic system in peripheral nerves. Tissue sections and isolated studies show that such a system exists. Concepts for the therapy of peripheral nerve injuries in relation to the lymphatic system are still completely undescribed in the literature. A better understanding could offer new approaches here. The question of the role of the lymphatic system also lends itself in particular to nerve compression injuries, such as carpal tunnel syndrome, a widespread occupational disease.

By precisely describing the lymphatic system in peripheral nerves with different degrees of injury for the first time, the scientists hope to gain new insights. If there is a connection, the stimulation of lymphatic vessel formation by means of growth factors could accelerate nerve healing or stop the progressive degeneration of a nerve.

Peripheral nerves are not the only topic at LBI Trauma – spinal cord injuries are also in focus. The main point of interest here is the prevention and reduction of consequential damage after a spinal cord injury. Only rarely is the spinal cord actually completely severed in an accident. A contusion is enough to cause extensive damage to the spinal cord. Inflammatory processes gradually break down the nerve tissue. The severing of the nerve tracts often occurs as a result of these destructive processes, days after the actual injury.

This subacute phase after the injury is considered one of the most clinically relevant phases for therapeutic interventions. Dr Hercher’s group is testing, for instance, the use of extracorporeal shock waves, which have already been able to demonstrate an improvement in regeneration and modulation of inflammatory processes in various tissues in laboratory tests. In fact, initial preclinical studies showed a functional improvement after spinal cord injuries when shock wave therapy was used.

What this positive effect is based on is currently deciphered in follow-up studies. Special imaging techniques are already in the process of being developed to make the extent of the damage and the effect of the applied therapies visible and measurable.