The malfunctioning of the glymphatic system during bacterial meningitis

Researchers at Karolinska Institute in Sweden show in a study on rats that the brain's tool for waste clearance, the glymphatic system, malfunctions during bacterial meningitis, causing a buildup of toxic garbage that damages brain cells. The findings are published in the journal mBio.

The researchers found higher amounts of bacterial waste products in the brains of rats with meningitis than in a control group. The concentrations were highest in the brain's cerebrospinal fluid compartments. In contrast, blood tests revealed low levels of bacterial components, indicating the glymphatic system had failed to drain the brain from bacteria and associated rest products. Over time, increased signs of neuroinflammation and neuronal damage were observed, with a corresponding loss of cognitive abilities. The researchers found that during pneumococcal meningitis, the AQP4-water channel lost its natural place and connection with the blood-brain barrier vessel wall. The astrocytic end-feet had detached from the vessel walls after the astrocytes swelled in response to the neuroinflammation caused by the bacterial infection.

Ref:

"Dysfunctional glymphatic system with disrupted aquaporin-4 expression pattern on astrocytes causes bacterial product accumulation in the CSF during pneumococcal meningitis." Jaqueline S. Generoso*, Sigrun Thorsdottir*, Allan Collodel, Diogo Dominguini, Roberta R. E. Santo, Fabricia Petronilho, Tatiana Barichello, Federico Iovino, mBio, online Aug. 29, 2022, doi: 10.1128/mbio.01886-22