Metformin Activates Neural Stem and Progenitor Cells in the Spinal Cord and Improves Functional Outcomes Following Injury

Abstract

Across mammals, spinal cord injuries (SCI) result in devastating functional deficits with minimal treatment options. Neural stem and progenitor cells (NSPCs) exist within the spinal cord and are located in the periventricular region lining the central canal. Although normally relatively quiescent and non‐neurogenic, these NSPCs are activated in response to injury, however their response is not sufficient to support functional recovery. Enhancing the response of resident NSPCs is an innovative approach to improve structural and functional outcomes following SCI. The FDA‐approved drug metformin (MET) has demonstrated efficacy in promoting neural repair in the injured brain where it expands the size of the NSPC pool and promotes both oligogenesis and neurogenesis from NSPCs. Here, we seek to determine whether MET can influence NSPCs within the spinal cord prior to and following SCI. Using the in vitro colony‐forming assay (neurosphere assay) we examined the size of the neural stem cell (NSC) pool in the spinal cord following 7 days of in vivo MET treatment. Females, but not males, demonstrated a three‐fold increase in the size of the NSC pool in response to MET treatment. Conversely, the differentiation profile of male and female‐derived NSPCs was not sex dependent in the presence of MET. Our results show that MET exposure led to an increase in oligogenesis across both males and females, with no change in neurogenesis. Next, we evaluated whether MET administration would improve functional outcomes following SCI using a dorsal column lesion in the thoracic spinal cord. MET was delivered to animals immediately post‐SCI and treatment resulted in a significantly reduced impairment at 7 days post‐injury (DPI) on a skilled walking task, compared to vehicle‐treated SCI mice. Strikingly, MET‐treated mice recovered to baseline by 14 DPI. Our data reveals that MET has differential effects on spinal cord NSPCs across males and females and that MET administration reduces the severity of SCI and results in improves functional outcomes post‐injury. Taken together, our results support MET as a viable therapeutic strategy for enhancing neural repair and improving recovery following SCI.Support or Funding InformationAmerican Association of AnatomistsOntario Institute for Regeneration MedicineKrembil FoundationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.