Geriatrics Research Education and Clinical Center, Puget Sound Health Care System, Seattle, Wash., USA.
Neuroimmunomodulation. 2012;19(2):121-30. doi: 10.1159/000330247. Epub 2012 Jan 11.
The blood-brain barrier (BBB) is not simply a physical barrier but a regulatory interface between the central nervous system (CNS) and immune system. The BBB both affects and is affected by the immune system and connects at many levels with the CNS, including the following: (1) the BBB transports cytokines and secretes various substances with neuroinflammatory properties; (2) transporters are altered in disease states including traumatic injury, Alzheimer's disease and inflammatory processes; (3) cytokines and other immune secretions from the cells comprising the BBB are both constitutive and inducible; (4) immune cells are transported across the BBB by the highly regulated process termed diapedesis, which involves communication and interactions between the brain endothelial cells and the immune cells; (5) the neuroimmune system has various effects on the BBB, including modulation of important transport systems and in extreme pathological conditions even disruption of the BBB, and (6) the brain-to-blood efflux transporter P-glycoprotein is altered in inflammatory conditions, thus affecting drug delivery to the brain. In summary, the BBB is an interactive interface that regulates and defines many of the ways that the CNS and the immune system communicate with one another.
血脑屏障（BBB）不仅仅是一个物理屏障，还是中枢神经系统（CNS）和免疫系统之间的调节界面。BBB 既影响免疫系统，也受免疫系统影响，并与 CNS 多方面连接，包括以下方面：（1）BBB 转运细胞因子并分泌具有神经炎症特性的各种物质；（2）在疾病状态下，转运蛋白发生改变，包括创伤性损伤、阿尔茨海默病和炎症过程；（3）组成 BBB 的细胞中的细胞因子和其他免疫分泌物既有组成型的，也有诱导型的；（4）免疫细胞通过高度调节的过程——穿越细胞（diapedesis）穿过 BBB，该过程涉及脑内皮细胞和免疫细胞之间的通讯和相互作用；（5）神经免疫系统对 BBB 有多种影响，包括对重要转运系统的调节，甚至在极端病理条件下破坏 BBB；（6）在炎症条件下，脑-血外排转运蛋白 P-糖蛋白发生改变，从而影响药物向大脑的输送。总之，BBB 是一个互动界面，调节和定义了 CNS 和免疫系统相互交流的许多方式。
