Systemic inflammation impairs microglial Aß clearance through NLRP3 inflammasome.

Alzheimer's disease is the most prevalent type of dementia and is caused by the deposition of extracellular amyloid-beta and abnormal tau phosphorylation. Neuroinflammation has emerged as an additional pathological component. Microglia, representing the brain's major innate immune cells, play an important role during Alzheimer's. Once activated, microglia show changes in their morphology, characterized by a retraction of cell processes. Systemic inflammation is known to increase the risk for cognitive decline in human neurogenerative diseases including Alzheimer's. Here, we assess for the first time microglial changes upon a peripheral immune challenge in the context of aging and Alzheimer's in vivo, using 2-photon laser scanning microscopy. Microglia were monitored at 2 and 10 days post-challenge by lipopolysaccharide. Microglia exhibited a reduction in the number of branches and the area covered at 2 days, a phenomenon that resolved at 10 days. Systemic inflammation reduced microglial clearance of amyloid-beta in APP/PS1 mice. NLRP3 inflammasome knockout blocked many of the observed microglial changes upon lipopolysaccharide, including alterations in microglial morphology and amyloid pathology. NLRP3 inhibition may thus represent a novel therapeutic target that may protect the brain from toxic peripheral inflammation during systemic infection.

Melodic Intonation Therapy for Post-stroke Non-fluent Aphasia: Systematic Review and Meta-Analysis.

Introduction: Melodic intonation therapy (MIT) is one of the most studied speech and language therapy (SLT) approaches for patients with non-fluent aphasia, although the methodological quality of the studies has been rated as low in previous reviews. The aim of this study is to update current evidence on the possible efficacy of MIT for the treatment of non-fluent post-stroke aphasia. Methods: A systematic review and meta-analysis. We selected randomized clinical trials (RCT) that included adult patients over 18 years of age with non-fluent post-stroke aphasia, whose intervention was MIT vs. no therapy or other therapy. We excluded non-RCT studies, mixed populations including patients with aphasia of non-stroke etiology, studies with no availability of post-stroke aphasia-specific data, and incomplete studies. Three sections of communicative ability were analyzed as outcomes: functional communication, expressive language (naming and repetition), and comprehension. Results: We identified a total of four eligible RCTs involving 94 patients. Despite the heterogeneity in the psychometric tests employed among the trials, a significant effect of MIT on functional communication (evaluated by the Communication Activity Log) was found (SMD 1.47; 95% CI 0.39-2.56). In addition, a positive effect of MIT on expressive language (repetition) was found (SMD 0.45; 95% CI 0.01-0.90). No significant effects on comprehension measurements were found, despite a lack of significant statistical heterogeneity. Conclusion: This systematic review and meta-analysis shows a significant effect of MIT on improving functional communication and on repetition tasks. Future larger RCT specifically addressing those outcomes should provide the definite evidence on the efficacy of MIT on post-stroke aphasia recovery. Systematic Review Registration:PROSPERO-URL https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020144604.