Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.
School of Medicine, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.
Brain. 2021 Nov 29;144(10):2933-2945. doi: 10.1093/brain/awab250.
After spinal cord injury, macrophages can exert either beneficial or detrimental effects depending on their phenotype. Aside from their critical role in inflammatory responses, macrophages are also specialized in the recognition, engulfment, and degradation of pathogens, apoptotic cells, and tissue debris. They promote remyelination and axonal regeneration by removing inhibitory myelin components and cellular debris. However, excessive intracellular presence of lipids and dysregulated intracellular lipid homeostasis result in the formation of foamy macrophages. These develop a pro-inflammatory phenotype that may contribute to further neurological decline. Additionally, myelin-activated macrophages play a crucial role in axonal dieback and retraction. Here, we review the opposing functional consequences of phagocytosis by macrophages in spinal cord injury, including remyelination and regeneration versus demyelination, degeneration, and axonal dieback. Furthermore, we discuss how targeting the phagocytic ability of macrophages may have therapeutic potential for the treatment of spinal cord injury.
脊髓损伤后,巨噬细胞的表型可以产生有益或有害的影响。除了在炎症反应中发挥关键作用外,巨噬细胞还专门识别、吞噬和降解病原体、凋亡细胞和组织碎片。它们通过去除抑制性髓鞘成分和细胞碎片来促进髓鞘再生和轴突再生。然而,脂质在细胞内的过度存在和细胞内脂质稳态的失调导致泡沫状巨噬细胞的形成。这些细胞表现出促炎表型,可能导致进一步的神经功能下降。此外,髓鞘激活的巨噬细胞在轴突回缩和退变中起着至关重要的作用。在这里,我们回顾了巨噬细胞吞噬作用在脊髓损伤中的相反功能后果,包括髓鞘再生和再生与脱髓鞘、退变和轴突回缩。此外,我们还讨论了如何靶向巨噬细胞的吞噬能力可能具有治疗脊髓损伤的潜力。