Study on the role of peripheral immune cells in cerebral ischemia

Stroke, primarily resulting from the sudden interruption of blood supply to the brain, remains a leading cause of morbidity and mortality worldwide. Following an ischemic stroke, the peripheral immune system significantly contributes to brain damage. Damage-associated molecular patterns (DAMPs) released from ischemic cells activate peripheral immune cells, resulting in increased inflammation and disruption of the blood-brain barrier (BBB). This review highlights the critical immune cells of the peripheral immune system activated after cerebral ischemia, with an emphasis on the roles of T cells, B cells, macrophages, and neutrophils. We discuss the pathophysiological mechanisms of cerebral ischemia, which include reduced blood flow, energy metabolism disorders, neuronal injury and death, and BBB disruption and cerebral edema. The interplay between the peripheral immune system and cerebral ischemia is explored, offering insights into the inflammatory and immunosuppressive responses following ischemic events. Meanwhile, current research advances and future research directions are presented, focusing on potential therapeutic targets within the peripheral immune system to improve outcomes in ischemic brain injury. In summary, this review underscores the necessity of understanding the peripheral immune system's role in cerebral ischemia to develop effective treatment strategies and enhance patient recovery.