scholarly journals Neuroprotective and Anti-Inflammatory Effects of Low–Moderate Dose Ionizing Radiation in Models of Alzheimer’s Disease

2020 ◽  
Vol 21 (10) ◽  
pp. 3678 ◽  
Author(s):  
Sujin Kim ◽  
Yunkwon Nam ◽  
Chanyang Kim ◽  
Hyewon Lee ◽  
Seojin Hong ◽  
...  

Alzheimer’s disease (AD) is the most common cause of dementia. The neuropathological features of AD include amyloid-β (Aβ) deposition and hyperphosphorylated tau accumulation. Although several clinical trials have been conducted to identify a cure for AD, no effective drug or treatment has been identified thus far. Recently, the potential use of non-pharmacological interventions to prevent or treat AD has gained attention. Low-dose ionizing radiation (LDIR) is a non-pharmacological intervention which is currently being evaluated in clinical trials for AD patients. However, the mechanisms underlying the therapeutic effects of LDIR therapy have not yet been established. In this study, we examined the effect of LDIR on Aβ accumulation and Aβ-mediated pathology. To investigate the short-term effects of low–moderate dose ionizing radiation (LMDIR), a total of 9 Gy (1.8 Gy per fraction for five times) were radiated to 4-month-old 5XFAD mice, an Aβ-overexpressing transgenic mouse model of AD, and then sacrificed at 4 days after last exposure to LMDIR. Comparing sham-exposed and LMDIR-exposed 5XFAD mice indicated that short-term exposure to LMDIR did not affect Aβ accumulation in the brain, but significantly ameliorated synaptic degeneration, neuronal loss, and neuroinflammation in the hippocampal formation and cerebral cortex. In addition, a direct neuroprotective effect was confirmed in SH-SY5Y neuronal cells treated with Aβ1–42 (2 μM) after single irradiation (1 Gy). In BV-2 microglial cells exposed to Aβ and/or LMDIR, LMDIR therapy significantly inhibited the production of pro-inflammatory molecules and activation of the nuclear factor-kappa B (NF-κB) pathway. These results indicate that LMDIR directly ameliorated neurodegeneration and neuroinflammation in vivo and in vitro. Collectively, our findings suggest that the therapeutic benefits of LMDIR in AD may be mediated by its neuroprotective and anti-inflammatory effects.

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Jack Rivers-Auty ◽  
Alison E Mather ◽  
Ruth Peters ◽  
Catherine B Lawrence ◽  
David Brough

Abstract Epidemiological evidence suggests non-steroidal anti-inflammatory drugs reduce the risk of Alzheimer’s disease. However, clinical trials have found no evidence of non-steroidal anti-inflammatory drug efficacy. This incongruence may be due to the wrong non-steroidal anti-inflammatory drugs being tested in robust clinical trials or the epidemiological findings being caused by confounding factors. Therefore, this study used logistic regression and the innovative approach of negative binomial generalized linear mixed modelling to investigate both prevalence and cognitive decline, respectively, in the Alzheimer’s Disease Neuroimaging dataset for each commonly used non-steroidal anti-inflammatory drug and paracetamol. Use of most non-steroidal anti-inflammatories was associated with reduced Alzheimer’s disease prevalence yet no effect on cognitive decline was observed. Paracetamol had a similar effect on prevalence to these non-steroidal anti-inflammatory drugs suggesting this association is independent of the anti-inflammatory effects and that previous results may be due to spurious associations. Interestingly, diclofenac use was significantly associated with both reduce incidence and slower cognitive decline warranting further research into the potential therapeutic effects of diclofenac in Alzheimer’s disease.


2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Zhenyan Song ◽  
Fang Yin ◽  
Biao Xiang ◽  
Bin Lan ◽  
Shaowu Cheng

In traditional Chinese medicine (TCM), Acori Tatarinowii Rhizoma (ATR) is widely used to treat memory and cognition dysfunction. This study aimed to confirm evidence regarding the potential therapeutic effect of ATR on Alzheimer’s disease (AD) using a system network level based in silico approach. Study results showed that the compounds in ATR are highly connected to AD-related signaling pathways, biological processes, and organs. These findings were confirmed by compound-target network, target-organ location network, gene ontology analysis, and KEGG pathway enrichment analysis. Most compounds in ATR have been reported to have antifibrillar amyloid plaques, anti-tau phosphorylation, and anti-inflammatory effects. Our results indicated that compounds in ATR interact with multiple targets in a synergetic way. Furthermore, the mRNA expressions of genes targeted by ATR are elevated significantly in heart, brain, and liver. Our results suggest that the anti-inflammatory and immune system enhancing effects of ATR might contribute to its major therapeutic effects on Alzheimer’s disease.


Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1250 ◽  
Author(s):  
Desanka Milanovic ◽  
Snjezana Petrovic ◽  
Marjana Brkic ◽  
Vladimir Avramovic ◽  
Milka Perovic ◽  
...  

Long-term fish oil (FO) supplementation is able to improve Alzheimer’s disease (AD) pathology. We aimed to determine the impact of short-term fish oil (FO) intake on phospholipids composition and plaque pathology in 5xFAD mice, a widely used animal model of AD. A 3-week-long FO supplementation administered at 3 months of age decreased the number of dense core plaques in the 5xFAD cortex and changed phospholipids in the livers and brains of wild-type (Wt) and 5xFAD mice. Livers of both genotypes responded by increase of n-3 and reciprocal decrease of n-6 fatty acids. In Wt brains, FO supplementation induced elevation of n-3 fatty acids and subsequent enhancement of n-6/n-3 ratio. However, in 5xFAD brains the improved n-6/n-3 ratio was mainly due to FO-induced decrease in arachidonic and adrenic n-6 fatty acids. Also, brain and liver abundance of n-3 fatty acids were strongly correlated in Wts, oppositely to 5xFADs where significant brain-liver correlation exists only for n-6 fatty acids. Expression of omega-3 transporter Mfs2a remained unchanged after FO supplementation. We have demonstrated that even a short-term FO intake improves the phospholipid composition and has a significant effect on plaque burden in 5xFAD brains when applied in early stages of AD pathology.


2020 ◽  
Vol 21 (12) ◽  
pp. 4532 ◽  
Author(s):  
Sujin Kim ◽  
Hyunju Chung ◽  
Han Ngoc Mai ◽  
Yunkwon Nam ◽  
Soo Jung Shin ◽  
...  

Alzheimer’s disease (AD) is the most common type of dementia. AD involves major pathologies such as amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain. During the progression of AD, microglia can be polarized from anti-inflammatory M2 to pro-inflammatory M1 phenotype. The activation of triggering receptor expressed on myeloid cells 2 (TREM2) may result in microglia phenotype switching from M1 to M2, which finally attenuated Aβ deposition and memory loss in AD. Low-dose ionizing radiation (LDIR) is known to ameliorate Aβ pathology and cognitive deficits in AD; however, the therapeutic mechanisms of LDIR against AD-related pathology have been little studied. First, we reconfirm that LDIR (two Gy per fraction for five times)-treated six-month 5XFAD mice exhibited (1) the reduction of Aβ deposition, as reflected by thioflavins S staining, and (2) the improvement of cognitive deficits, as revealed by Morris water maze test, compared to sham-exposed 5XFAD mice. To elucidate the mechanisms of LDIR-induced inhibition of Aβ accumulation and memory loss in AD, we examined whether LDIR regulates the microglial phenotype through the examination of levels of M1 and M2 cytokines in 5XFAD mice. In addition, we investigated the direct effects of LDIR on lipopolysaccharide (LPS)-induced production and secretion of M1/M2 cytokines in the BV-2 microglial cells. In the LPS- and LDIR-treated BV-2 cells, the M2 phenotypic marker CD206 was significantly increased, compared with LPS- and sham-treated BV-2 cells. Finally, the effect of LDIR on M2 polarization was confirmed by detection of increased expression of TREM2 in LPS-induced BV2 cells. These results suggest that LDIR directly induced phenotype switching from M1 to M2 in the brain with AD. Taken together, our results indicated that LDIR modulates LPS- and Aβ-induced neuroinflammation by promoting M2 polarization via TREM2 expression, and has beneficial effects in the AD-related pathology such as Aβ deposition and memory loss.


Author(s):  
K. Duff ◽  
D.B. Hammers ◽  
B.C.A. Dalley ◽  
K.R. Suhrie ◽  
T.J. Atkinson ◽  
...  

Background: Practice effects, which are improvements in cognitive test scores due to repeated exposure to testing materials, may provide information about Alzheimer’s disease pathology, which could be useful for clinical trials enrichment. Objectives: The current study sought to add to the limited literature on short-term practice effects on cognitive tests and their relationship to amyloid deposition on neuroimaging. Participants: Twenty-seven, non-demented older adults (9 cognitively intact, 18 with mild cognitive impairment) received amyloid imaging with 18F-Flutemetamol, and two cognitive testing sessions across one week to determine practice effects. Results: A composite measure of 18F-Flutemetamol uptake correlated significantly with all seven cognitive tests scores on the baseline battery (r’s = -0.61 – 0.59, all p’s<0.05), with higher uptake indicating poorer cognition. Practice effects significantly added to the relationship (above and beyond the baseline associations) with 18F-Flutemetamol uptake on 4 of the 7 cognitive test scores (partial r’s = -0.45 – 0.44, p’s<0.05), with higher uptake indicating poorer practice effects. The odds ratio of being “amyloid positive” was 13.5 times higher in individuals with low practice effects compared to high practice effects. Conclusions: Short-term practice effects over one week may be predictive of progressive dementia and serve as an affordable screening tool to enrich samples for preventative clinical trials in Alzheimer’s disease.


2021 ◽  
pp. 1-14
Author(s):  
Xiaodi Sun ◽  
Xinjun Suo ◽  
Xianyou Xia ◽  
Chunshui Yu ◽  
Yan Dou

Background: Dimethyl fumarate (DMF) has been approved for clinical treatment of multiple sclerosis based on its antioxidant and anti-inflammatory effects by activating the Nrf2 pathway. Since both oxidative stress and inflammation are involved in Alzheimer’s disease (AD), DMF is a potential therapeutic option for AD. Objective: This study aims to test the therapeutic effects of DMF on AD model mice and to reveal its underlying molecular mechanisms. Methods: Cell viability assay and in vitro immunofluorescence imaging were used to evaluate the antioxidant effect of DMF on embryonic mouse hippocampal neurons. Behavioral test and brain magnetic resonance imaging were used to assess the therapeutic effects of DMF on spatial learning and memory as well as hippocampal volume in AD model mice with and without Nrf2 knockdown. Western blotting was used to analyze the expression of antioxidant enzymes and molecules associated with AD-related pathological pathways. Results: DMF inhibits reactive oxygen species overproduction and protects neurons without Nrf2 knockdown from death. DMF reduces amyloid-β induced memory impairment and hippocampal atrophy in AD model mice rather than in Nrf2 knockdown AD mice. DMF delays the progression of AD by activating the Nrf2 pathway to enhance the expression of downstream antioxidant enzymes and inhibits lipid peroxidation, apoptosis, inflammation, mitochondrial dysfunction and amyloid-β deposition. Conclusion: These results indicate that DMF is a potential therapeutic option for AD through its antioxidant, anti-inflammatory, anti-apoptotic, and other anti-AD effects by activating the Nrf2 pathway.


2020 ◽  
Vol 28 (6) ◽  
pp. 1439-1455
Author(s):  
Olumayokun A. Olajide ◽  
Satyajit D. Sarker

Abstract Alzheimer’s disease (AD) is the most common form of dementia and affects 44 million people worldwide. New emerging evidence from pre-clinical and clinical investigations shows that neuroinflammation is a major pathological component of AD suggesting that anti-inflammatory strategies are important in delaying the onset or slowing the progression of the disease. However, efforts to employ current anti-inflammatory agents in AD clinical trials have produced limited success. Consequently, there is a need to explore anti-inflammatory natural products, which target neuroinflammatory pathways relevant to AD pathogenesis. This review summarises important druggable molecular targets of neuroinflammation and presents classes of anti-neuroinflammatory natural products with potentials for preventing and reducing symptoms of AD.


Author(s):  
S. Dubé ◽  
J.T. Megerian ◽  
R. Malamut

Agitation is a common and burdensome symptom associated with Alzheimer’s disease (AD). This is a narrative literature review of the designs and methods used in randomized clinical trials of agitation in patients with AD; sources range from published, to completed but not published, to ongoing studies in the past 10 years. Selection for review included blinded, randomized trials conducted to assess the effect of a pharmacological intervention for which agitation in patients with AD was among the prespecified end points. Key criteria for exclusion included open-label studies, trials of dementia not specific to AD, or mixed populations of AD and unspecified dementia. A search of PubMed and clinicaltrials.gov databases identified 36 trials for which agitation was among the prespecified end points: 18 were published trials and 18 were completed but not published or ongoing. There was significant heterogeneity among AD studies in terms of diagnostic criteria, assessment of severity of disease and agitation, sample size and powering assumptions, treatment duration, patient age and cognitive status, and outcomes measurements. Few studies used a mitigation strategy for placebo response. Accumulating evidence suggests that it is important to consider the following in trial design: thresholds for baseline severity of agitation and AD; use of prespecified accepted criteria to define agitation; and use of standardized, validated tools to measure treatment effects during a trial. Adoption of these design strategies might help improve signal detection and bring us closer to identifying the most appropriate, effective, and safe treatments for agitation in patients with AD.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Izumi Maezawa ◽  
David Paul Jenkins ◽  
Benjamin E. Jin ◽  
Heike Wulff

There exists an urgent need for new target discovery to treat Alzheimer’s disease (AD); however, recent clinical trials based on anti-Aβand anti-inflammatory strategies have yielded disappointing results. To expedite new drug discovery, we propose reposition targets which have been previously pursued by both industry and academia for indications other than AD. One such target is the calcium-activated potassium channel KCa3.1 (KCNN4), which in the brain is primarily expressed in microglia and is significantly upregulated when microglia are activated. We here review the existing evidence supporting that KCa3.1 inhibition could block microglial neurotoxicity without affecting their neuroprotective phagocytosis activity and without being broadly immunosuppressive. The anti-inflammatory and neuroprotective effects of KCa3.1 blockade would be suitable for treating AD as well as cerebrovascular and traumatic brain injuries, two well-known risk factors contributing to the dementia in AD patients presenting with mixed pathologies. Importantly, the pharmacokinetics and pharmacodynamics of several KCa3.1 blockers are well known, and a KCa3.1 blocker has been proven safe in clinical trials. It is therefore promising to reposition old or new KCa3.1 blockers for AD preclinical and clinical trials.


Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1702
Author(s):  
Afsana Tajmim ◽  
Areli K. Cuevas-Ocampo ◽  
Abu Bakar Siddique ◽  
Mohammed H. Qusa ◽  
Judy Ann King ◽  
...  

Alzheimer’s disease (AD) is a complex progressive neurodegenerative disorder affecting humans mainly through the deposition of Aβ-amyloid (Aβ) fibrils and accumulation of neurofibrillary tangles in the brain. Currently available AD treatments only exhibit symptomatic relief but do not generally intervene with the amyloid and tau pathologies. The extra-virgin olive oil (EVOO) monophenolic secoiridoid S-(–)-oleocanthal (OC) showed anti-inflammatory activity through COX system inhibition with potency comparable to the standard non-steroidal anti-inflammatory drug (NSAID) like ibuprofen. OC also showed positive in vitro, in vivo, and clinical therapeutic effects against cardiovascular diseases, many malignancies, and AD. Due to its pungent, astringent, and irritant taste, OC should be formulated in acceptable dosage form before its oral use as a potential nutraceutical. The objective of this study is to develop new OC oral formulations, assess whether they maintained OC activity on the attenuation of β-amyloid pathology in a 5xFAD mouse model upon 4-month oral dosing use. Exploration of potential OC formulations underlying molecular mechanism is also within this study scope. OC powder formulation (OC-PF) and OC-solid dispersion formulation with erythritol (OC-SD) were prepared and characterized using FT-IR spectroscopy, powder X-ray diffraction, and scanning electron microscopy (SEM) analyses. Both formulations showed an improved OC dissolution profile. OC-PF and OC-SD improved memory deficits of 5xFAD mice in behavioral studies. OC-PF and OC-SD exhibited significant attenuation of the accumulation of Aβ plaques and tau phosphorylation in the brain of 5xFAD female mice. Both formulations markedly suppressed C3AR1 (complement component 3a receptor 1) activity by targeting the downstream marker STAT3. Collectively, these results demonstrate the potential for the application of OC-PF as a prospective nutraceutical or dietary supplement to control the progression of amyloid pathogenesis associated with AD.


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