Hundreds of millions of people worldwide experience some form of peripheral nerve damage, either from injury or disease. Because these nerves do not fully regenerate, individuals are often left with sensory or motor deficits, or pain. New research from the Hotchkiss Brain Institute (HBI) has discovered that a naturally occurring protein can enhance the repair of these damaged nerves in animal models and restore motor and sensory deficits. The study, which was led by the HBI’s Shalina Ousman, PhD was published recently in the journal Proceedings of the National Academy of Sciences (PNAS).
“We wanted to determine what is responsible for the incomplete regeneration of these nerves and how we can enhance regrowth,” says Ousman who is an Associate Professor in the Department of Clinical Neurosciences. “Imagine not being able to use your arms or legs or being in chronic pain. This severely disrupts the quality of life of affected individuals.”
Peripheral nerves are axonal fibers (projections of nerves) that extend throughout the entire body and form connections with the brain and spinal cord. Damage can be the result of an accident where the nerve is physically crushed or severed, the result of disease such as diabetes, or from various medications or chemotherapies. Because these nerves do not regenerate adequately in humans, affected individuals can be left with numbness or tingling in the respective body part, or in extreme cases, loss of feeling or motor function altogether. While surgery is currently the best option in situations where the nerves are severed and can be re-attached, the intervention rarely restores full nerve function.
Prior research informs study
Ousman’s previous research focused on the protein alphaB-crystallin (alphaBC) in the context of multiple sclerosis (MS). It was during these studies that she located some reports suggesting that the protein is also expressed in Schwann cells. Schwann cells support nerve cells in the peripheral nervous system and some produce myelin – a fatty substance that coats the axons of nerves and permits the rapid conduction of nerve impulses. When myelin is damaged or destroyed, nerve impulses are slowed or interrupted, leading to sensory or motor deficits.
Together with her PhD student Erin-Mai Lim, Ousman set to work looking more closely at what role alphaBC played in Schwann cells and if it could influence peripheral nerve regrowth.
Ousman explains, “we found that the protein contributed to the formation of myelin and, as a consequence, led to improvement in electrical conductivity and functional recovery, particularly in situations of nerve damage.”
PhD student carries research forward
Armed with this encouraging data, Lim and Ousman carried their work forward into an animal model, where they observed that when mice with nerve damage were injected with the alphaBC, they were able to recover from their injuries faster than those that were not injected with the protein.
“We were very pleased to discover that we can in fact use this protein to enhance the regeneration of nerves and to restore nerve function,” Lim says.
While the findings are promising, the researchers are quick to caution that further investigation is required before they can investigate the effects of alphaBC in humans with peripheral nerve damage.
“What we plan to do next is to discuss our findings with clinical researchers to discuss the most appropriate next steps in translating this research,” says Ousman. “New and specific therapies are urgently needed and this work is perhaps one step closer to improved quality of life for millions of people worldwide.”
Led by the HBI, Brain and Mental Health is one of six strategic research themes guiding the University of Calgary towards its Eyes High goals.