Newswise — In the pursuit to better enable regional anesthesia for the treatment of chronic pain, modulation of neuro-immune pathways in the brain and spinal cord may represent novel therapeutic targets. According to research from investigators at Millennium Pain Center and Lumbrera, LLC, targeting of microglial activation phenotypes, such as the M1 and M2, may help control patients’ chronic pain.

William Smith, Satya Sanapati, David Cedeno, Courtney Kelley, Dana Tilley, and Ricardo Vallejo received a Best of Meeting Abstract Award for their abstract of the study, “Effect of SCS on M1 and M2 Microglia Activation,” which will be presented on Saturday, November 16, 2019, during the 18th Annual Pain Medicine Meeting in New Orleans, LA.

As researchers continue to build the knowledge base around microglia cells in the central nervous system, their dynamic role in the development and attenuation of chronic pain becomes more apparent. Microglia are hypothesized to have a multitude of activation phenotypes, including the inflammatory M1 phenotype and the neuroprotective, healing M2 phenotype, depending on the environment and phase of chronic pain development.  

In their study, Smith and colleagues examined the effects of high-rate (HR) or low-rate (LR) spinal cord stimulation (SCS) therapy on M1 and M2 activation in rats with the spared nerve injury model of neuropathic pain. RNA sequencing of dorsal spinal cord tissue showed that the pain model upregulated about 48% of M1 and 49% of M2 microglia activation genes compared to naïve expression. Gene expression of M1 microglia after HR-SCS correlated most significantly with gene expression in naïve animals. In contrast, gene expression of M2 microglia after LR-SCS most significantly correlated with the expression of naïve animals.

The researchers explain that preferentially activating M2 microglia may be beneficial for pain control. “As the role of microglia in chronic pain is further elucidated, it is essential to understand how M1 and M2 microglia are differentially activated by injury and modulated by SCS to optimize SCS therapy and improve patient outcomes,” the authors conclude.

The 18th Annual Pain Medicine Meeting will be held November 14–16, 2019, in New Orleans, LA. The conference brings together national and international experts in pain medicine to offer translational and clinical information that pain practitioners can implement directly in practice.