Targeting new therapeutic options for chronic pain

A recent study published in Scientific Reports by Sascha Alles,’16 PhD, and Peter Smith, professor emeritus in the University of Alberta’s Department of Pharmacology, found that a growth factor called brain-derived neurotrophic factor (BDNF) can help inhibit chronic pain..

Pain is a natural protective mechanism that prevents damage to our body, but sometimes even once an injury has healed, pain persists and becomes chronic. A recent study published in Scientific Reports by Sascha Alles,’16 PhD, and Peter Smith, professor emeritus in the University of Alberta’s Department of Pharmacology, found that a growth factor called brain-derived neurotrophic factor (BDNF) previously thought to only stimulate the pathways that cause chronic pain actually can also inhibit them. This finding may have the potential to lead to options other than the current opioid treatments, which often come with serious side-effects and is highly addictive. 

Chronic pain is most commonly associated with phantom limb pain, diabetic neuropathy, nervous system infection and fibromyalgia. More recently, it has also been associated with COVID-19. Despite an increasing number of people suffering from chronic pain, a clear biological explanation for its cause has yet to be determined. 

In their study, Alles and Smith measured changes in neurons localized in the spinal dorsal horn after exposure to BDNF. The first neurons to receive potential damaging signals from the periphery of our body, they transmit these signals to the brain. By using an ex vivo rat model, the researchers found that BDNF is involved in the chronic pain mechanism in a more complex way than expected. They found that long-term treatment with the molecule not only inhibited certain neurons but unmasked others, showing a cell-type specificity. 

“We found that this molecule involved in pain (BDNF) is both switching things on and off at the same time but in different cells. It is like pressing the gas pedal in one vehicle and the brake pedal in another one,” Alles explains.

The researchers believe that the identification of different subtypes of neurons affected by BDNF will help them to develop more specific interventions for chronic pain management, and hopefully reduce the need for opioid treatments.     

Peter Smith received funding from the Canadian Institutes for Health Research. Sascha Alles received funding from the research endowment fund of the Department of Anesthesiology and Critical Care Medicine, University of New Mexico Health Sciences Center.