| 1. |
- Fisher, Jane, et al.
(författare)
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A functional observational battery for evaluation of neurological outcomes in a rat model of acute bacterial meningitis
- 2020
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Ingår i: Intensive Care Medicine Experimental. - : Springer Science and Business Media LLC. - 2197-425X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background Acute bacterial meningitis is a disease with a high mortality and a high incidence of neurological sequelae in survivors. There is an acute need to develop new adjuvant therapies. To ensure that new therapies evaluated in animal models are translatable to humans, studies must evaluate clinically relevant and patient-important outcomes, including neurological symptoms and sequelae. Methods We developed and tested a functional observational battery to quantify the severity of a variety of relevant neurological and clinical symptoms in a rat model of bacterial meningitis. The functional observational battery included symptoms relating to general clinical signs, gait and posture abnormalities, involuntary motor movements, focal neurological signs, and neuromotor abnormalities which were scored according to severity and summed to obtain a combined clinical and neurological score. To test the functional observational battery, adult Sprague-Dawley rats were infected by intracisternal injection of a clinical isolate of Streptococcus pneumoniae. Rats were evaluated for 6 days following the infection. Results Pneumococcal meningitis was not lethal in this model; however, it induced severe neurological symptoms. Most common symptoms were hearing loss (75% of infected vs 0% of control rats; p = 0.0003), involuntary motor movements (75% of infected vs 0% of control rats; p = 0.0003), and gait and posture abnormality (67% of infected vs 0% of control rats; p = 0.0013). Infected rats had a higher combined score when determined by the functional observational battery than control rats at all time points (24 h 12.7 ± 4.0 vs 4.0 ± 2.0; 48 h 17.3 ± 7.1 vs 3.4 ± 1.8; 6 days 17.8 ± 7.4 vs 1.7 ± 2.4; p < 0.0001 for all). Conclusions The functional observational battery described here detects clinically relevant neurological sequelae of bacterial meningitis and could be a useful tool when testing new therapeutics in rat models of meningitis.
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| 2. |
- Mohanty, Tirthankar, et al.
(författare)
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Neutrophil extracellular traps in the central nervous system hinder bacterial clearance during pneumococcal meningitis
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 1667-1667
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils are crucial mediators of host defense that are recruited to the central nervous system (CNS) in large numbers during acute bacterial meningitis caused by Streptococcus pneumoniae. Neutrophils release neutrophil extracellular traps (NETs) during infections to trap and kill bacteria. Intact NETs are fibrous structures composed of decondensed DNA and neutrophil-derived antimicrobial proteins. Here we show NETs in the cerebrospinal fluid (CSF) of patients with pneumococcal meningitis, and their absence in other forms of meningitis with neutrophil influx into the CSF caused by viruses, Borrelia and subarachnoid hemorrhage. In a rat model of meningitis, a clinical strain of pneumococci induced NET formation in the CSF. Disrupting NETs using DNase I significantly reduces bacterial load, demonstrating that NETs contribute to pneumococcal meningitis pathogenesis in vivo. We conclude that NETs in the CNS reduce bacterial clearance and degrading NETs using DNase I may have significant therapeutic implications.
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| 3. |
- Pavan, Chiara, et al.
(författare)
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DNase Treatment Prevents Cerebrospinal Fluid Block in Early Experimental Pneumococcal Meningitis
- 2021
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Ingår i: Annals of Neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 90:4, s. 653-669
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Ramos, Marta, et al.
(författare)
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Cisterna Magna Injection in Rats to Study Glymphatic Function
- 2019
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Ingår i: Methods in molecular biology (Clifton, N.J.). - New York, NY : Springer New York. - 1940-6029. ; 1938, s. 97-104
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Tidskriftsartikel (refereegranskat)abstract
- The recently discovered glymphatic system, which supports brain-wide clearance of metabolic waste, has become the subject of intense research within the past few years. Its nomenclature arose due to its functionally analogous nature to the lymphatic system in combination with glial cells that are part of its anatomical boundaries. The influx of cerebrospinal fluid (CSF) from perivascular spaces into the brain interstitium acts to clear intraparenchymal solutes. CSF is produced by the choroid plexus and flows from the ventricles to the subarachnoid space via the cisterna magna, and as such the injection of tracer molecules into any one of these spaces could be used for studying CSF movement through the glymphatic system. Of these options, the cisterna magna is most favorable as it offers a route of entry that does not involve craniotomy. Herein we describe the cisterna magna (CM) injection procedure carried out in rats, essential for studying glymphatic influx and efflux dynamics.
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