Effects of imeglimin on mitochondrial functions and ischemic brain damage in young and aging rats

Imeglimin, a novel oral antidiabetic drug, has been suggested to affect mitochondrial functions in some types of cells and tissues, however, it has never been investigated whether aging has an impact on its pharmacological effects in the brain. In this study, we investigated whether imeglimin directly affects functions of brain mitochondria and whether its intraperitoneal injection protects against ischemic brain injury in young, middle-aged and aged Wistar rats. We found that direct addition of imeglimin to mitochondria isolated from young and middle-aged rat brains suppressed oxidative phosphorylation and activities of mitochondrial Complexes I and IV. The opposite, stimulating effect on Complex II activity was observed within the same groups. Injection of imeglimin 24 h before simulated brain ischemia in vitro reduced infarct size only in young and middle-aged rat groups. In the aged rat group, imeglimin did not reduce cerebral infarct size nor directly modulate mitochondrial respiration and activities of the complexes. In conclusion, we provided novel evidence on potential effects of imeglimin in the brain by demonstrating a direct stimulating effect on mitochondrial Complex II activity and age-dependent protective effects against brain injury under in vitro simulated ischemia.