Laboratory of Experimental Neurology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, Santa Catarina, Brazil.
Department of Neuroscience, Karolinska Institutegrid.4714.6t, Biomedicum, Stockholm, Sweden.
mBio. 2022 Oct 26;13(5):e0188622. doi: 10.1128/mbio.01886-22. Epub 2022 Aug 29.
Pneumococcal meningitis, inflammation of the meninges due to an infection of the Central Nervous System caused by Streptococcus pneumoniae (the pneumococcus), is the most common form of community-acquired bacterial meningitis globally. Aquaporin 4 (AQP4) water channels on astrocytic end feet regulate the solute transport of the glymphatic system, facilitating the exchange of compounds between the brain parenchyma and the cerebrospinal fluid (CSF), which is important for the clearance of waste away from the brain. Wistar rats, subjected to either pneumococcal meningitis or artificial CSF (sham control), received Evans blue-albumin (EBA) intracisternally. Overall, the meningitis group presented a significant impairment of the glymphatic system by retaining the EBA in the CSF compartments compared to the uninfected sham group. Our results clearly showed that during pneumococcal meningitis, the glymphatic system does not function because of a detachment of the astrocytic end feet from the blood-brain barrier (BBB) vascular endothelium, which leads to misplacement of AQP4 with the consequent loss of the AQP4 water channel's functionality. The lack of solute drainage due to a dysfunctional glymphatic system leads to an increase of the neurotoxic bacterial material in the CSF compartments of the brain, ultimately leading to brain-wide neuroinflammation and neuronal damage with consequent impairment of neurological functions. The loss of function of the glymphatic system can therefore be a leading cause of the neurological sequelae developing post-bacterial meningitis.
肺炎球菌性脑膜炎,是由肺炎链球菌(肺炎球菌)引起的中枢神经系统感染导致的脑膜炎症,是全球最常见的社区获得性细菌性脑膜炎形式。星形胶质细胞终足上的水通道蛋白 4(AQP4)调节神经淋巴系统的溶质转运,促进脑实质和脑脊液(CSF)之间化合物的交换,这对于清除大脑中的废物非常重要。Wistar 大鼠分别患有肺炎球菌性脑膜炎或人工 CSF(假对照),接受了脑室内 Evans 蓝白蛋白(EBA)。总体而言,与未感染的假对照组相比,脑膜炎组由于 CSF 隔室中 EBA 的保留,明显损害了神经淋巴系统。我们的研究结果清楚地表明,在肺炎球菌性脑膜炎期间,由于星形胶质细胞终足与血脑屏障(BBB)血管内皮分离,神经淋巴系统功能失调,导致 AQP4 错位,随之丧失 AQP4 水通道的功能。由于神经淋巴系统功能失调导致溶质排出减少,导致 CSF 隔室中的神经毒性细菌物质增加,最终导致全脑神经炎症和神经元损伤,从而导致神经功能受损。因此,神经淋巴系统功能丧失可能是细菌性脑膜炎后出现神经后遗症的主要原因。