Research progress of drug therapy related to neuroinflammation in Alzheimer's disease

Yanxing ZHOU, Xiaohua XIAO, Chunhua LIANG, Xueqin YAN, Huoyou HU

Chinese Journal of Alzheimer's Disease and Related Disorders ›› 2024, Vol. 7 ›› Issue (3) : 218-225.

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Chinese Journal of Alzheimer's Disease and Related Disorders

Abbreviation (ISO4): Chinese Journal of Alzheimer's Disease and Related Disorders      Editor in chief: Jun WANG

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Chinese Journal of Alzheimer's Disease and Related Disorders ›› 2024, Vol. 7 ›› Issue (3) : 218-225. DOI: 10.3969/j.issn.2096-5516.2024.03.011
Review

Research progress of drug therapy related to neuroinflammation in Alzheimer's disease

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Abstract

This review aims to explore the molecular mechanism and pathophysiological characteristics of neuroinflammation in AD, and summarize the latest advances in drug treatment of neuroinflammation in including glial cell inhibitors (such as non-steroidal anti-inflammatory drugs, glucocorticoids, etc.), inflammatory mediator inhibitors (such as monoclonal antibodies, TNF-α inhibitors, etc.), anti-inflammatory siRNA therapy, anti-inflammatory Chinese medicine,etc. The clinical efficacy of the above drugs in the treatment of AD is compared, and their potential mechanisms of action and adverse effects are discussed, which provides a valuable reference for future research and clinical practice.

Key words

Alzheimer's disease / Neuroinflammation / Medical treatment

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Yanxing ZHOU , Xiaohua XIAO , Chunhua LIANG , et al . Research progress of drug therapy related to neuroinflammation in Alzheimer's disease[J]. Chinese Journal of Alzheimer's Disease and Related Disorders. 2024, 7(3): 218-225 https://doi.org/10.3969/j.issn.2096-5516.2024.03.011

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β-amyloid plaques and neurofibrillary tau deposits biologically define Alzheimer disease.To perform post hoc analyses of amyloid reduction after donanemab treatment and assess its association with tau pathology and clinical measures.The Study of LY3002813 in Participants With Early Symptomatic Alzheimer's Disease (TRAILBLAZER-ALZ) was a phase 2, placebo-controlled, randomized clinical trial conducted from December 18, 2017, to December 4, 2020, with a double-blind period of up to 76 weeks and a 48-week follow-up period. The study was conducted at 56 centers in the US and Canada. Enrolled were participants from 60 to 85 years of age with gradual and progressive change in memory function for 6 months or more, early symptomatic Alzheimer disease, elevated amyloid, and intermediate tau levels.Donanemab (an antibody specific for the N-terminal pyroglutamate β-amyloid epitope) dosing was every 4 weeks: 700 mg for the first 3 doses, then 1400 mg for up to 72 weeks. Blinded dose-reduction evaluations occurred at 24 and 52 weeks based on amyloid clearance.Change in amyloid, tau, and clinical decline after donanemab treatment.The primary study randomized 272 participants (mean [SD] age, 75.2 [5.5] years; 145 female participants [53.3%]). The trial excluded 1683 of 1955 individuals screened. The rate of donanemab-induced amyloid reduction at 24 weeks was moderately correlated with the amount of baseline amyloid (Spearman correlation coefficient r, -0.54; 95% CI, -0.66 to -0.39; P < .001). Modeling provides a hypothesis that amyloid would not reaccumulate to the 24.1-centiloid threshold for 3.9 years (95% prediction interval, 1.9-8.3 years) after discontinuing donanemab treatment. Donanemab slowed tau accumulation in a region-dependent manner as measured using neocortical and regional standardized uptake value ratios with cerebellar gray reference region. A disease-progression model found a significant association between percentage amyloid reduction and change on the integrated Alzheimer Disease Rating Scale only in apolipoprotein E (APOE) ε4 carriers (95% CI, 24%-59%; P < .001).Results of post hoc analyses for donanemab-treated participants suggest that baseline amyloid levels were directly associated with the magnitude of amyloid reduction and inversely associated with the probability of achieving complete amyloid clearance. The donanemab-induced slowing of tau was more pronounced in those with complete amyloid clearance and in brain regions identified later in the pathologic sequence. Data from other trials will be important to confirm aforementioned observations, particularly treatment response by APOE ε4 status.ClinicalTrials.gov Identifier: NCT03367403.
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The NLR family, pyrin domain containing 3 (NLRP3) inflammasome drives the progression of Alzheimer's disease (AD). Ginkgolide B (GB) is a potential anti-inflammatory compound that controls neuro-inflammation. The aim of this study was to evaluate the effect of GB on the NLRP3 inflammasome in AD. The effect of GB on the conversion between the M1 and M2 microglial phenotype was examined using quantitative real-time PCR and immunostaining. Western blotting assays and ELISA were used to detect changes in neuro-inflammation following GB treatment, including the NLRP3 inflammasome pathway and autophagy. In order to evaluate the cognitive function of male senescence-accelerated mouse prone 8 (SAMP8) mice, behavioral tests, including the Morris water maze and novel object recognition tests, were performed. GB significantly decreased the intracellular pro-inflammatory cytokine levels in lipopolysaccharide-treated BV2 cells and improved cognitive behavior in SAMP8 mice. Moreover, GB deactivated the NLRP3 inflammasome, and this effect was dependent on autophagy. Ubiquitination was associated with GB-induced autophagic NLRP3 degradation. These results were further validated in the hippocampus of SAMP8 mice. Thus, GB exerted a neuroprotective effect on the cognitive function of SAMP8 mice by suppressing the activation of NLRP3 inflammasome via autophagic degradation.© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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Lin H, Dixon SG, Hu W, et al. p38 MAPK is a major regulator of amyloid beta-Induced IL-6 expression in human microglia[j]. Mol Neurobiol, 2022, 59(9):5284-5298.
The accumulation of amyloid beta (Aβ) plaques in the brain is a hallmark of Alzheimer's disease (AD) pathology. Microglial activation-mediated neuroinflammation has been implicated in the pathogenesis of AD and the expression levels of interleukin-6 (IL-6) were increased in the brains of AD patients. However, the mechanisms by which IL-6 expression is regulated in human microglia are incompletely understood. Here, we show that Aβ oligomers (Aβ) dose-dependently stimulate IL-6 expression in HMC3 human microglial cells. Treatment with Aβ promotes the transcription of IL-6 and tumor necrosis factor α (TNFα) mRNAs in both HMC3 and THP-1 cells. Mechanistic studies reveal that Aβ-induced increase of IL-6 secretion is associated with the activation of p38 mitogen-activated protein kinase (p38 MAPK). Inhibition of p38 MAPK by BIRB 796 or SB202190 abrogates Aβ-induced increase of IL-6 production. Through analyzing brain specimens, we found that the immunoreactivity for IL-6 and phosphorylated (the activated form) p38 MAPK was markedly higher in microglia of AD patients than in age-matched control subjects. Moreover, our studies identified the co-localization of IL-6 with phosphorylated p38 MAPK in microglia in the cortices of AD patients. Taken together, these results indicate that p38 MAPK is a major regulator of Aβ-induced IL-6 production in human microglia, which suggests that targeting p38 MAPK may represent a new approach to ameliorate Aβ accumulation-induced neuroinflammation in AD.© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
[40]
Braun DJ, Frazier HN, Davis VA, et al. Early chronic suppression of microglial p38α in a model of Alzheimer's disease does not significantly alter amyloid-associated neuropathology[J]. PLoS One, 2023, 18(5):e0286495.
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Sims JR, Zimmer JA, Evans CD, et al. TRAILBLAZER-ALZ 2 investigators. donanemab in early symptomatic Alzheimer disease: the TRAILBLAZER-ALZ 2 randomized clinical trial[J]. JAMA, 2023, 330(6):512-527.
There are limited efficacious treatments for Alzheimer disease.To assess efficacy and adverse events of donanemab, an antibody designed to clear brain amyloid plaque.Multicenter (277 medical research centers/hospitals in 8 countries), randomized, double-blind, placebo-controlled, 18-month phase 3 trial that enrolled 1736 participants with early symptomatic Alzheimer disease (mild cognitive impairment/mild dementia) with amyloid and low/medium or high tau pathology based on positron emission tomography imaging from June 2020 to November 2021 (last patient visit for primary outcome in April 2023).Participants were randomized in a 1:1 ratio to receive donanemab (n = 860) or placebo (n = 876) intravenously every 4 weeks for 72 weeks. Participants in the donanemab group were switched to receive placebo in a blinded manner if dose completion criteria were met.The primary outcome was change in integrated Alzheimer Disease Rating Scale (iADRS) score from baseline to 76 weeks (range, 0-144; lower scores indicate greater impairment). There were 24 gated outcomes (primary, secondary, and exploratory), including the secondary outcome of change in the sum of boxes of the Clinical Dementia Rating Scale (CDR-SB) score (range, 0-18; higher scores indicate greater impairment). Statistical testing allocated α of.04 to testing low/medium tau population outcomes, with the remainder (.01) for combined population outcomes.Among 1736 randomized participants (mean age, 73.0 years; 996 [57.4%] women; 1182 [68.1%] with low/medium tau pathology and 552 [31.8%] with high tau pathology), 1320 (76%) completed the trial. Of the 24 gated outcomes, 23 were statistically significant. The least-squares mean (LSM) change in iADRS score at 76 weeks was -6.02 (95% CI, -7.01 to -5.03) in the donanemab group and -9.27 (95% CI, -10.23 to -8.31) in the placebo group (difference, 3.25 [95% CI, 1.88-4.62]; P < .001) in the low/medium tau population and -10.2 (95% CI, -11.22 to -9.16) with donanemab and -13.1 (95% CI, -14.10 to -12.13) with placebo (difference, 2.92 [95% CI, 1.51-4.33]; P < .001) in the combined population. LSM change in CDR-SB score at 76 weeks was 1.20 (95% CI, 1.00-1.41) with donanemab and 1.88 (95% CI, 1.68-2.08) with placebo (difference, -0.67 [95% CI, -0.95 to -0.40]; P < .001) in the low/medium tau population and 1.72 (95% CI, 1.53-1.91) with donanemab and 2.42 (95% CI, 2.24-2.60) with placebo (difference, -0.7 [95% CI, -0.95 to -0.45]; P < .001) in the combined population. Amyloid-related imaging abnormalities of edema or effusion occurred in 205 participants (24.0%; 52 symptomatic) in the donanemab group and 18 (2.1%; 0 symptomatic during study) in the placebo group and infusion-related reactions occurred in 74 participants (8.7%) with donanemab and 4 (0.5%) with placebo. Three deaths in the donanemab group and 1 in the placebo group were considered treatment related.Among participants with early symptomatic Alzheimer disease and amyloid and tau pathology, donanemab significantly slowed clinical progression at 76 weeks in those with low/medium tau and in the combined low/medium and high tau pathology population.ClinicalTrials.gov Identifier: NCT04437511.
[42]
Matsunaga S, Kishi T, Nomura I, et al. The efficacy and safety of memantine for the treatment of Alzheimer's disease[J]. Expert Opin Drug Saf, 2018, 17(10):1053-1061.
Currently, five pharmacotherapeutic options are available to treat Alzheimer's disease: memantine; the three cholinesterase inhibitors donepezil, galantamine, and rivastigmine; and combination treatments with memantine and one cholinesterase inhibitor. Selection of the best course of treatment is based upon the evidence gathered by systematic reviews and meta-analyses of randomized controlled trials. Areas covered: This article provides a risk-benefit analysis of these treatments using evidence from meta-analyses on their safety and their efficacy. Expert opinion: Memantine improves cognitive functions and behavioral disturbances more efficiently than the placebo, both as monotherapy and in combination with donepezil. Although memantine monotherapy and combination therapy are associated with a few individual adverse events such as somnolence, it is well-tolerated and its safety (all-cause discontinuation) is comparable or superior to that of the placebo (agitation). Pooled cholinesterase inhibitors are superior to the placebo in the improvement of cognitive functions, but not behavioral disturbances and they are not well-tolerated, as evaluated by the high discontinuation rate. Donepezil (10 mg/day) and oral rivastigmine and galantamine monotherapies carry the risk for some adverse events including gastrointestinal symptoms. Therefore, we consider that combined treatment with memantine and donepezil is the most useful treatment for Alzheimer's disease.
[43]
Sinniah A, Yazid S, Flower RJ, et al. From NSAIDs to glucocorticoids and beyond[J]. Cells, 2021, 10(12):3524.
[44]
Ismail Z, Creese B, Aarsland D, et al. Psychosis in Alzheimer disease - mechanisms, genetics and therapeutic opportunities[J]. Nat Rev Neurol, 2022, 18(3):131-144.
Psychosis is a common and distressing symptom in people with Alzheimer disease, and few safe and effective treatments are available. However, new approaches to symptom assessment and treatment are beginning to drive the field forward. New nosological perspectives have been provided by incorporating the emergence of psychotic symptoms in older adults - even in advance of dementia - into epidemiological and neurobiological frameworks as well as into diagnostic and research criteria such as the International Psychogeriatric Association criteria for psychosis in neurocognitive disorders, the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) research criteria for psychosis in neurodegenerative disease, and the ISTAART criteria for mild behavioural impairment. Here, we highlight the latest findings in genomics, neuroimaging and neurobiology that are informing approaches to drug discovery and repurposing. Current pharmacological and non-pharmacological treatment options are discussed, with a focus on safety and precision medicine. We also explore trial data for pimavanserin, a novel agent that shows promise for the treatment of psychosis in people with dementia, and discuss existing agents that might be useful but need further exploration such as escitalopram, lithium, cholinesterase inhibitors and vitamin D. Although the assessment and management of psychosis in people with dementia remain challenging, new opportunities are providing direction and hope to the field.© 2022. Springer Nature Limited.
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