Ischemic stroke is a major cause of disability. No efficient therapy is currently available, except for the removal of the occluding blood clot during the first hours after symptom onset. Loss of function after stroke is due to cell death in the infarcted tissue, cell dysfunction in the peri-infarct region, as well as dysfunction and neurodegeneration in remote brain areas. Plasticity responses in spared brain regions are a major contributor to functional recovery, while secondary neurodegeneration in remote regions is associated with depression and impedes the long-term outcome after stroke. Hypoxic-ischemic encephalopathy due to birth asphyxia is the leading cause of neurological disability resulting from birth complications. Despite major progress in neonatal care, approximately 50% of survivors develop complications such as mental retardation, cerebral palsy or epilepsy. The C3a receptor (C3aR) is expressed by many cell types including neurons and glia. While there is a body of evidence for its deleterious effects in the acute phase after ischemic injury to the adult brain, C3aR signaling contributes to better outcome in the post-acute and chronic phase after ischemic stroke in adults and in the ischemic immature brain. Here we discuss recent insights into the novel roles of C3aR signaling in the ischemic brain with focus on the therapeutic opportunities of modulating C3aR activity to improve the outcome after ischemic stroke and birth asphyxia.

缺血性中风是致残的主要原因。目前没有有效的治疗方法，除了在症状出现后的最初几个小时内去除阻塞的血凝块。中风后功能丧失是由于梗塞组织中的细胞死亡、梗塞周围区域的细胞功能障碍以及偏远脑区的功能障碍和神经退行性变。备用大脑区域的可塑性反应是功能恢复的主要因素，而偏远区域的继发性神经退行性变与抑郁症有关，并阻碍中风后的长期结果。由出生窒息引起的缺氧缺血性脑病是由出生并发症引起的神经功能障碍的主要原因。尽管新生儿护理取得了重大进展，但仍有约 50% 的幸存者出现智力低下等并发症，脑瘫或癫痫。C3a 受体 (C3aR) 由许多细胞类型表达，包括神经元和神经胶质细胞。虽然有大量证据表明其在成人脑缺血性损伤后的急性期具有有害影响，但 C3aR 信号传导有助于成人缺血性中风后急性期和慢性期和缺血性未成熟脑的更好结果。在这里，我们讨论了最近对 C3aR 信号在缺血性脑中的新作用的见解，重点是调节 C3aR 活性以改善缺血性中风和出生窒息后结果的治疗机会。C3aR 信号传导有助于成人缺血性卒中后急性期和慢性期和缺血性未成熟脑的更好结果。在这里，我们讨论了最近对 C3aR 信号在缺血性脑中的新作用的见解，重点是调节 C3aR 活性以改善缺血性中风和出生窒息后结果的治疗机会。C3aR 信号传导有助于成人缺血性卒中后急性期和慢性期和缺血性未成熟脑的更好结果。在这里，我们讨论了最近对 C3aR 信号在缺血性脑中的新作用的见解，重点是调节 C3aR 活性以改善缺血性中风和出生窒息后结果的治疗机会。