The article discusses the dual role of microglia and macrophages in brain repair after injury. While these cells can promote neurogenesis, axonal regeneration, and other neurorestorative processes, they can also hinder CNS repair and expand tissue damage. The authors propose that this dual role is due to the polarization of these cells into different phenotypes, such as M1 (pro-inflammatory) and M2 (anti-inflammatory). They highlight recent breakthroughs in understanding the regulatory molecules that control this polarization, which could lead to new therapeutic approaches. The article also explores the dynamic nature of microglia and macrophage polarization, the functions of different phenotypes in brain repair, and the potential of targeting specific phenotypes to enhance recovery. Finally, it discusses the challenges and considerations in translating these findings into clinical practice, emphasizing the need for further research in human systems.The article discusses the dual role of microglia and macrophages in brain repair after injury. While these cells can promote neurogenesis, axonal regeneration, and other neurorestorative processes, they can also hinder CNS repair and expand tissue damage. The authors propose that this dual role is due to the polarization of these cells into different phenotypes, such as M1 (pro-inflammatory) and M2 (anti-inflammatory). They highlight recent breakthroughs in understanding the regulatory molecules that control this polarization, which could lead to new therapeutic approaches. The article also explores the dynamic nature of microglia and macrophage polarization, the functions of different phenotypes in brain repair, and the potential of targeting specific phenotypes to enhance recovery. Finally, it discusses the challenges and considerations in translating these findings into clinical practice, emphasizing the need for further research in human systems.