Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO, USA.
Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.
J Cereb Blood Flow Metab. 2024 Jun;44(6):841-856. doi: 10.1177/0271678X241237070. Epub 2024 Feb 28.
Subarachnoid hemorrhage is a devastating sequela of aneurysm rupture. Because it disproportionately affects younger patients, the population impact of hemorrhagic stroke from subarachnoid hemorrhage is substantial. Secondary brain injury is a significant contributor to morbidity after subarachnoid hemorrhage. Initial hemorrhage causes intracranial pressure elevations, disrupted cerebral perfusion pressure, global ischemia, and systemic dysfunction. These initial events are followed by two characterized timespans of secondary brain injury: the early brain injury period and the delayed cerebral ischemia period. The identification of varying microglial phenotypes across phases of secondary brain injury paired with the functions of microglia during each phase provides a basis for microglia serving a critical role in both promoting and attenuating subarachnoid hemorrhage-induced morbidity. The duality of microglial effects on outcomes following SAH is highlighted by the pleiotropic features of these cells. Here, we provide an overview of the key role of microglia in subarachnoid hemorrhage-induced secondary brain injury as both cytotoxic and restorative effectors. We first describe the ontogeny of microglial populations that respond to subarachnoid hemorrhage. We then correlate the phenotypic development of secondary brain injury after subarachnoid hemorrhage to microglial functions, synthesizing experimental data in this area.
蛛网膜下腔出血是动脉瘤破裂的毁灭性后果。由于它不成比例地影响年轻患者，蛛网膜下腔出血引起的出血性中风对人口的影响是巨大的。继发性脑损伤是蛛网膜下腔出血后发病率的一个重要因素。最初的出血导致颅内压升高、脑灌注压破坏、全脑缺血和全身功能障碍。这些初始事件之后是继发性脑损伤的两个特征时间段：早期脑损伤期和迟发性脑缺血期。在继发性脑损伤的各个阶段，不同的小胶质细胞表型的鉴定，以及小胶质细胞在每个阶段的功能，为小胶质细胞在促进和减轻蛛网膜下腔出血引起的发病率方面发挥关键作用提供了基础。小胶质细胞对蛛网膜下腔出血后结果的双重影响突出了这些细胞的多效性特征。在这里，我们概述了小胶质细胞在蛛网膜下腔出血引起的继发性脑损伤中作为细胞毒性和修复效应器的关键作用。我们首先描述了对蛛网膜下腔出血有反应的小胶质细胞群体的个体发生。然后，我们将蛛网膜下腔出血后继发性脑损伤的表型发展与小胶质细胞功能相关联，综合了该领域的实验数据。
