© Felix Rioux

The Pioneer

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Professor Samuel David paved the way for modern Neuroregeneration. At the beginning of the 1980s, he published a groundbreaking research paper that proved the nerve cells of the spinal cord are capable of regeneration in the right environment.

As Austrian neurologist and thinker, Sigmund Freud, so famously said: “The progress of science is slow, tentative, and laborious,” which also applies to spinal cord research. Quick results are exceedingly rare. More often than not, researchers have to be content with small steps. From time to time, however, a scientist achieves a significant breakthrough. Professor Samuel David, a researcher at McGill University, is one of the few who have succeeded in making a huge leap forward. Up until 1981, it was believed that damaged nerves in the spinal cord are unable to recover. David proved the otherwise.

A few years earlier
David’s career path can be described as atypical. At 18 years of age, he studied physiotherapy and worked in various hospitals in India, before finally emigrating to Canada in 1969. As part of his day-to-day work, David spent a lot of time with patients suffering from spinal cord injuries. He assisted them in adjusting to their new life and maximising their potential. Soon he started to wonder why the spinal cord is unable to recover from an injury, especially as peripheral nerves are capable of regenerating. David decided that he needed to know more about the biological background of this specific type of injury, which is why he went to university and studied neuroscience in Winnipeg, Canada.

Revolutionary insights 
After successfully completing his PhD, David began his research at McGill University in Montreal. He and his colleague, Albert Aguayo, started looking for answers to David’s questions. In one experiment, he bridged the spinal cord injury with a peripheral nerve extracted from the leg. He attached one end of the inactive nerve graft to the spinal cord above the injury, while attaching the other end below the injury. Six weeks later, he observed that new axons had formed over the entire length of the graft – a veritable sensation. This discovery was a turning point and inspired science to search for more factors that stimulate or inhibit the growth of nerve cells.

Further discoveries
Samuel David had no intentions of resting on his laurels and continued his research. A few years later, he and his colleagues discovered that a molecule called MAG (myelin associated glycoprotein) inhibits the growth of nerve cells. Yet another discovery followed shortly after. David found out that certain immune cells (macrophages) can contribute to the regeneration of the adult nervous system. This realisation inspired other scientists to research macrophages and their potential intensively. David’s most recent discovery was published in the Neuron journal in 2014. He described how the protein TNF and the element iron can exacerbate secondary damage following a spinal cord injury. David is currently investigating how inflammation and its associated immune cells contribute to secondary damage after a spinal cord injury and other diseases, such as multiple sclerosis. Furthermore, he is eager to find out more about the role iron plays in respect of neurological conditions.

Consultant and mentor
David has received numerous awards for his research. He is also an in-demand reviewer for prestigious journals such as Cell, Neuron, and Nature. David is also keen to pass on his vast knowledge to the next generation, in the hope that others can make equally significant leaps forward in terms of regenerative medicine in the future.

 (Felix Rioux)
© Felix Rioux

Name: Professor Samuel David
Institute: Institute of Neurology & Neurosurgery at McGill University in Montreal, Canada
Position at Wings for Life: Member of the Scientific Advisory Board
Number of publications: 106
Significant publications
1981: Central nerve cells can regenerate when placed in the right environment (Science)
1990: Diffusible factors released by a special type of immune cells called macrophages can stimulate adult central nervous system regeneration (Neuron)
1997: Ceruloplasmin is expressed by astrocytes. It regulates iron levels in the CNS and prevents free radical injury (Journal of Biological Chemistry)
2007: Role of Nogo receptor in macrophage clearance (Neuron)
2014: Cytokine TNF and iron can worsen inflammation-induced secondary damage after spinal cord injury (Neuron)