DNase Treatment Prevents Cerebrospinal Fluid Block in Early Experimental Pneumococcal Meningitis

Objective Streptococcus pneumoniae is the most common cause of bacterial meningitis, a disease that, despite treatment with antibiotics, still is associated with high mortality and morbidity worldwide. Diffuse brain swelling is a leading cause of morbidity in S pneumoniae meningitis. We hypothesized that neutrophil extracellular traps (NETs) disrupt cerebrospinal fluid (CSF) transport by the glymphatic system and contribute to edema formation in S pneumoniae meningitis. Methods We used DNase I treatment to disrupt NETs and then assessed glymphatic function by cisterna magna injections of CSF tracers in a rat model of S pneumoniae meningitis. Results Our analysis showed that CSF influx into the brain parenchyma, as well as CSF drainage to the cervical lymph nodes, was significantly reduced in the rat model of S pneumoniae meningitis. Degrading NETs by DNase treatment restored glymphatic transport and eliminated the increase in brain weight in the rats. In contrast, first-line antibiotic treatment had no such effect on restoring fluid dynamics. Interpretation This study suggests that CSF accumulation is responsible for cerebral edema formation and identifies the glymphatic system and NETs as possible new treatment targets in S pneumoniae meningitis. ANN NEUROL 2021

Automated summary

In this study, it was found that NETs disrupt the transport of cerebrospinal fluid through the glymphatic system in pneumococcal meningitis, leading to the formation of cerebral edema. Treatment with DNase can restore glymphatic transport and reduce the increased brain weight in rats, while first-line antibiotic treatment does not have the same effect on restoring fluid dynamics. Therefore, the glymphatic system and NETs may be potential new treatment targets in pneumococcal meningitis.