Microglia cells release a protein that activates pain neurons
Montreal - December 2005
A Canadian multidisciplinary, multi-institutional research team has discovered a key mechanism behind neuropathic pain, a finding that could soon lead to better diagnostics and new kinds of therapeutics. This breakthrough was made possible with the support of a $1.5-million NeuroScience Canada Brain Repair Program team grant that enabled five scientists from across Canada to join their labs and fast-track their research. Two of the members of the grant led the work at the Hospital for Sick Children in Toronto and the Robert-Giffard Research Centre in Québec City.
This research will be reported in the December 15, 2005 issue of the journal Nature.
Damage to peripheral nerves, after nerve injury or from diseases that affect peripheral nerve function, can result in neuropathic pain, one of the most debilitating types of chronic pain. Neuropathic pain can afflict people with diabetes, cancer, HIV and spinal cord injury. Previous work has shown that a first step in neuropathic pain depends on the activation of microglia cells, but scientists have long sought to understand how microglia communicate with pain neurons that relay information from the spinal cord.
In the December 15th issue of Nature, Dr. Yves De Koninck and Dr. Michael Salter, and their team, report that upon stimulation, microglia cells release a protein (called brain-derived neurotrophic factor) that alters the properties of pain neurons in the spinal cord in such a way that they become activated - rather than inhibited (as would normally be the case) - by the signaling molecule GABA.
Since current pain relieving drugs, such as morphine, act on the actual nerve cells, they are ineffective in the treatment of neuropathic pain. The findings reported by Dr. Salter and De Konick indicate that drugs that are capable of stopping the microglia from injuring nerve cells will be key to treating this type of pain.
“This is an important discovery for the millions of Canadians who suffer from debilitating chronic pain that cannot currently be treated. The cost to society is equally devastating and is estimated in the billions of dollars annually,” says the Honourable Michael H. Wilson, Chair of NeuroScience Canada, a national umbrella organization for neuroscience research, whose Brain Repair Program helped support this research. “With the work of Drs. Salter and De Koninck, we can now focus the research on developing drugs that will target the class of cells responsible for chronic pain. This represents an important shift that could soon provide patients with effective treatments and allow them to be active again in our society.”
* The date and time embargo on information to be released adheres to the agreement signed by the publisher of the magazine Nature which publishes in extinso the results of this project Ten million Canadians of all ages will be affected by a disease, disorder or injury of the brain, spinal cord or nervous system at some point in their lives. These conditions number more than 1,000 and include Alzheimer’s disease, Parkinson’s disease, stroke, multiple sclerosis, spinal cord injury, depression, schizophrenia, sense organ diseases, traumatic brain injury and chronic pain. Based on Health Canada data, the economic burden of these disorders is conservatively estimated at 14 per cent of the total burden of disease, or $22.7 billion annually; when disability is included, the economic burden reaches 38 per cent or more, according to the World Health Organization. However, despite the magnitude of the problem, neuroscience research, with just $100 million total in operating grants in Canada annually, is still greatly under funded in this country.
Founded in 1988, NeuroScience Canada is Canada’s umbrella organization and voice for the neurosciences. Through partnering with the public, private and voluntary sectors, NeuroScience Canada connects the knowledge and resources available in this area to accelerate neuroscience research and funding, and maximize the output of Canada’s world-class scientists and researchers.
The mission of NeuroScience Canada’s Brain Repair Program is to fast-track neuroscience research in order to develop treatments and therapies more quickly. Through the Brain Repair Program, NeuroScience Canada and its donors and partners have already invested $4.5 million to research teams conducting breakthrough work in the area of brain repair. NeuroScience Canada’s funding partners on the grant led by Dr. Salter include the Canadian Institutes of Health Research and the Ontario Neurotrauma Foundation. The goal of the Brain Repair Program is to initially fund five teams, for a total investment of $8 million.
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Anie Perrault, Media Relations