Alzheimer's Disease: Past, Present, and Future

Allosterism of Nicotinic Acetylcholine Receptors: Therapeutic Potential for Neuroinflammation Underlying Brain Trauma and Degenerative Disorders

Inflammation is a key physiological phenomenon that can be pervasive when dysregulated. Persistent chronic inflammation precedes several pathophysiological conditions forming one of the critical cellular homeostatic checkpoints. With a steady global surge in inflammatory diseases, it is imperative to delineate underlying mechanisms and design suitable drug molecules targeting the cellular partners that mediate and regulate inflammation. Nicotinic acetylcholine receptors have a confirmed role in influencing inflammatory pathways and have been a subject of scientific scrutiny underlying drug development in recent years. Drugs designed to target allosteric sites on the nicotinic acetylcholine receptors present a unique opportunity to unravel the role of the cholinergic system in regulating and restoring inflammatory homeostasis. Such a therapeutic approach holds promise in treating several inflammatory conditions and diseases with inflammation as an underlying pathology. Here, we briefly describe the potential of cholinergic allosterism and some allosteric modulators as a promising therapeutic option for the treatment of neuroinflammation.

Codonopsis pilosula polysaccharide attenuates Aβ toxicity and cognitive defects in APP/PS1 mice

Codonopsis pilosula Polysaccharides (CPPs), a traditional Chinese medicine used for thousands of years, is a potential neuroprotective polysaccharide via a relatively poorly understood mechanism. We previously reported that CPPs attenuated tau pathology in hTau transfected mice and therefore in the current work investigated the effect of CPPs on Aβ toxicity and cognitive defects in APP/PS1 mice model. It was found that one-month intragastric administration of CPPs significantly ameliorated cognitive defects in APP/PS1 mice. In addition, CPPs treatment mitigated the loss of the synaptic plasticity and increased the synaptic proteins including synaptotagmin and PSD95. The expression of Aβ42 and Aβ40 was remarkably decreased in the hippocampus of APP/PS1 mice after CPPs treatment. We also found that CPPs coincubation significantly reduced the amount of APPβ and Aβ42 expression in cells. Intriguingly, the activity of BACE1 was decreased following CPPs treatment in both the hippocampus of APP/PS1 mice and in vitro experiments. Collectively, these results indicated that CPPs attenuated Aβ pathology in APP/PS1 mice, and down-regulating BACE1 might be the underlaying mechanism which could be a therapeutic target for alleviating cognitive defects in AD pathology.

DL0410 attenuates oxidative stress and neuroinflammation via BDNF/TrkB/ERK/CREB and Nrf2/HO-1 activation

Oxidative stress and neuroinflammation have been deeply associated with Alzheimer's disease. DL0410 is a novel acetylcholinesterase inhibitor with potential anti-oxidative effects in AD-related animal models, while the specific mechanism has not been fully clarified. In this study, DL0410 was predicted to be related to the modification of cell apoptosis, oxidation-reduction process, inflammatory response and ERK1/ERK2 cascade by in silico target fishing and GO enrichment analysis. Then the possible protective effects of DL0410 were evaluated by hydrogen peroxide (H₂O₂)-induced oxidative stress model and lipopolysaccharides (LPS)-induced neuroinflammation model H₂O₂ decreased the viability of SH-SY5Y cells, induced malondialdehyde (MDA) accumulation, mitochondrial membrane potential (Δψm) loss and cell apoptosis, which could be reversed by DL0410 dose-dependently, indicating that DL0410 protected SH-SY5Y cells against H₂O₂-mediated oxidative stress. Western blot analysis showed that DL0410 increased the H₂O₂-triggered down-regulated TrkB, ERK and CREB phosphorylation and the expression of BDNF. In addition, TrkB inhibitor ANA-12, ERK inhibitor SCH772984 and CREB inhibitor 666-15 eliminated the inhibition of DL0410 on MDA accumulation and Δψm loss. Furthermore, DL0410 attenuates inflammatory responses and ROS production in LPS-treated BV2 cells, which is responsible for Nrf2 and HO-1 up-regulation. The present study demonstrates that DL0410 is a potential activator of the BDNF/TrkB/ERK/CREB and Nrf2/HO-1 pathway and may be a potential candidate for regulating oxidative stress and neuroinflammatory response in the brain. Together, the results showed that DL0410 is a promising drug candidate for treating AD and possibly other nervous system diseases associated with oxidative stress and neuroinflammation.

Post-Developmental Roles of Notch Signaling in the Nervous System

Since its discovery in Drosophila, the Notch signaling pathway has been studied in numerous developmental contexts in diverse multicellular organisms. The role of Notch signaling in nervous system development has been extensively investigated by numerous scientists, partially because many of the core Notch signaling components were initially identified through their dramatic ‘neurogenic’ phenotype of developing fruit fly embryos. Components of the Notch signaling pathway continue to be expressed in mature neurons and glia cells, which is suggestive of a role in the post-developmental nervous system. The Notch pathway has been, so far, implicated in learning and memory, social behavior, addiction, and other complex behaviors using genetic model organisms including Drosophila and mice. Additionally, Notch signaling has been shown to play a modulatory role in several neurodegenerative disease model animals and in mediating neural toxicity of several environmental factors. In this paper, we summarize the knowledge pertaining to the post-developmental roles of Notch signaling in the nervous system with a focus on discoveries made using the fruit fly as a model system as well as relevant studies in C elegans, mouse, rat, and cellular models. Since components of this pathway have been implicated in the pathogenesis of numerous psychiatric and neurodegenerative disorders in human, understanding the role of Notch signaling in the mature brain using model organisms will likely provide novel insights into the mechanisms underlying these diseases.

Protective Effects of Co-administration of Zinc and Selenium Against Streptozotocin-Induced Alzheimer's Disease: Behavioral, Mitochondrial Oxidative Stress, and GPR39 Expression Alterations in Rats

Changes in the concentrations of trace metals such as zinc (Zn) and selenium (Se) can pathologically lead to neurodegenerative conditions such as the Alzheimer's disease (AD). Previous studies have shown that mitochondrial dysfunction plays an important role in the pathogenesis of AD. Several male Wistar rats were randomly divided into five groups: sham group, AD group that received 3 mg/kg of streptozotocin (STZ) intracerebroventricularly, AD + Zn group that received 10 mg/kg of Zn intraperitoneally (i.p.) for 1 week, AD + Se group that received 0.1 mg/kg of Se i.p. for 1 week, and AD + Zn + Se group that received 10 mg/kg of Zn i.p. plus 0.1 mg/kg of Se i.p. for 1 week. At end of the study, behavioral tests and mitochondrial oxidative stress and GPR39 gene expression evaluations were carried out. Co-administration of Zn and Se significantly decreased the potential collapse of mitochondrial membrane, reactive oxygen species levels, and lipid peroxidation levels while significantly increased cognitive performance, superoxide dismutase (SOD), glutathione peroxidase, and catalase activity in the brain mitochondria compared with the STZ group. In addition, no significant changes were observed in GPR39 expression in the co-treated group. Findings of the current study showed that ZnR/GPR39 receptor, mitochondrial dysfunction, and oxidative stress play important roles in the pathogenesis of AD. Co-treatment of Zn and Se improved the cognitive performance, mitochondrial dysfunction, and oxidative stress caused by STZ-induced AD. Therefore, therapeutic approaches to improve mitochondrial function could be effective in preventing the initiation and progression of AD.

Synthesis of furocoumarin-stilbene hybrids as potential multifunctional drugs against multiple biochemical targets associated with Alzheimer's disease

A series of furocoumarin-stilbene hybrids has been synthesized and evaluated in vitro for inhibitory effect against acetylcholinesterase (AChE), butyrylcholinestarase (BChE), β-secretase, cyclooxygenase-2 (COX-2), and lipoxygenase-5 (LOX-5) activities including free radical-scavenging properties. Among these hybrids, 8-(3,5-dimethoxyphenyl)-4-(3,5-dimethoxystyryl)furochromen-2-one 4h exhibited significant anticholinesterase activity and inhibitory effect against β-secretase, COX-2 and LOX-5 activities. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and an in vitro cell-based antioxidant activity assay involving lipopolysaccharide induced reactive oxygen species production revealed that 4h has capability of scavenging free radicals. Molecular docking into AChE, BChE, β-secretase, COX-2 and LOX-5 active sites has also been performed.

Effect of Glycyrrhizic Acid on Scopolamine-Induced Cognitive Impairment in Mice

Purpose

Cognitive impairment is one of the main symptoms of Alzheimer disease and other dementias. Glycyrrhiza uralensis is a natural product that has a protective effect against cognitive impairment. In this study, we investigated whether glycyrrhizic acid, among the main bioactive components of Glycyrrhiza uralensis, has a neuroprotective effect on scopolamine-induced cognitive impairment.

Methods

Twenty-week-old male Institute of Cancer Research mice were used in this study. The scopolamine-induced cognitive impairment mice model was used. Glycyrrhizic acid was orally administered to mice once daily for 21 days, while scopolamine (1 mg/kg) treatment was delivered 30 minutes before behavioral tests. Donepezil (2 mg/kg) was used as a positive drug control. To evaluate the effect of glycyrrhizic acid, the following assessments were performed on hippocampal tissue: Y-maze test, acetylcholinesterase activity, antioxidant enzymes’ activity (superoxide dismutase, catalase). Western blotting for phosphor-extracellular signal-regulated kinase, P38, and c-Jun NH2-terminal kinase was conducted.

Results

We found that glycyrrhizic acid administration significantly improved scopolamine-induced cognitive impairment in the Y-maze test. The acetylcholinesterase activity, superoxide dismutase, and catalase activity in the glycyrrhizic acid-treated group showed a significant reversal of cognitive impairment compared with the scopolamine-treated group.

Conclusions

Our results suggest that glycyrrhizic acid has a neuroprotective effect on cognitive function in scopolamine-induced cognitive impairment.

Potentiation of anti-Alzheimer activity of curcumin by probiotic Lactobacillus rhamnosus UBLR-58 against scopolamine-induced memory impairment in mice

Curcumin, a major component of Indian saffron through clinical studies, revealed its neuroprotective effect in neurodegenerative diseases. However, it has not been utilized alone orally due to its low bioavailability. There are certain strategies to overcome the drawbacks such as poor absorption and low aqueous solubility. Many strategies are utilized to increase the systemic availability of curcumin. Among them, the steady intestinal and liver metabolism of curcumin by a curcumin adjuvant (enzyme inhibitor/inducer) is an important and less engrossed strategy for improving the overall systemic bioavailability of curcumin. Here, we assess the effect of probiotic Lactobacillus rhamnosus as a curcumin adjuvant (potentiate the effect of curcumin) in scopolamine-induced dementia in mice. To induce amnesia, scopolamine was used in a mouse model (1 mg/kg, daily for 10 days i.p.). After execution of behavioural tests (Morris water maze test), brains and liver were isolated for further neurochemical and histopathology examination. Our results showed a significant increase in antioxidant enzyme levels in curcumin with a probiotic group compared with curcumin alone. Besides, histopathology study results showed less neuronal damage of curcumin with probiotics as compared with the curcumin and scopolamine alone groups. Additionally, curcumin with probiotics improved memory and cognitive functions in the behavioural study with the significance of p ≤ 0.0001. In conclusion, curcumin with probiotics has greater activity as compared with curcumin alone and reverses the hallmarks of Alzheimer's disease (AD).

Integrated network pharmacology and zebrafish model to investigate dual-effects components of Cistanche tubulosa for treating both Osteoporosis and Alzheimer's Disease

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoporosis (OP) and Alzheimer's disease (AD) are common geriatric concurrent diseases, and many studies indicate the connection of their pathogenesis. Cistanche tubulosa (Schenk) Wight (CT) is a widely used traditional Chinese medicine and has been extensively applied to treat OP and AD, respectively. However, the active ingredients for both concurrent diseases simultaneously and underlying mechanisms are limited.

AIM OF STUDY

This work aimed at establishing an effective and reliable network screening method to find dual-effects compounds in CT that can protect AD and OP concurrently. And it will provide new perspectives of the link between OP and AD on molecular mechanisms.

MATERIAL AND METHODS

The dual-effects of CT were systematically analyzed with integrating multiple databases and extensive analysis at a network pharmacology level. Classified drug-target interaction network was constructed to reveal differences in effects between different types of compounds. To prove the effectiveness of this network, some compounds were selected to verify in Pre-induced OP model and AlCl₃-induced AD model of zebrafish according to the topological parameters.

RESULTS

22 dual-effects active ingredients in CT were initially screened out via network pharmacology with a closely connection with 81 OP and AD-related targets. Classified network analysis found the better bioactivities of phenylethanoid glycosides and flavonoids. The dual-effects of four selected compounds demonstrated that the network is reasonable and effective, suggesting the dual-effects of the remaining 18 compounds. Moreover, we identified 9 putative targets and two pathways that were significantly related to OP and AD.

CONCLUSIONS

We successfully identified 22 dual-effects active components in CT. This systematic screening strategy provided a new protocol to objectively discover multi-effects compounds of traditional Chinese medicine, and even a macroscopic perspective that will improve our understanding of the link between OP and AD on molecular mechanisms.

Expression of Genes Involved in Axon Guidance: How Much Have We Learned?

Neuronal axons are guided to their target during the development of the brain. Axon guidance allows the formation of intricate neural circuits that control the function of the brain, and thus the behavior. As the axons travel in the brain to find their target, they encounter various axon guidance cues, which interact with the receptors on the tip of the growth cone to permit growth along different signaling pathways. Although many scientists have performed numerous studies on axon guidance signaling pathways, we still have an incomplete understanding of the axon guidance system. Lately, studies on axon guidance have shifted from studying the signal transduction pathways to studying other molecular features of axon guidance, such as the gene expression. These new studies present evidence for different molecular features that broaden our understanding of axon guidance. Hence, in this review we will introduce recent studies that illustrate different molecular features of axon guidance. In particular, we will review literature that demonstrates how axon guidance cues and receptors regulate local translation of axonal genes and how the expression of guidance cues and receptors are regulated both transcriptionally and post-transcriptionally. Moreover, we will highlight the pathological relevance of axon guidance molecules to specific diseases.

MiR-539-5p Decreases amyloid β-protein production, hyperphosphorylation of Tau and Memory Impairment by Regulating PI3K/Akt/GSK-3β Pathways in APP/PS1 Double Transgenic Mice

The production of amyloid β (Aβ) and tau hyperphosphorylation have been identified as key processes in Alzheimer's disease (AD) pathogenesis. MiR-539-5p has been found to be abnormally expressed in brain tissue; however, the functional role of miR-539-5p in the pathogenesis of AD remains unclear. In our study, we found that the expression of miR-539-5p was significantly downregulated in humans and mice with AD and was negatively correlated with expression of APP, caveolin 1, and GSK-3β. Moreover, upregulation of miR-539-5p inhibited Aβ accumulation, tau phosphorylation, oxidative stress, and apoptosis and improved memory ability in AD mice. Furthermore, by using bioinformatics tool and dual-luciferase reporter assay, APP, Caveolin 1, and GSK-3β were confirmed as direct targets of miR-539-5p. In addition, the PI3K/AKT/GSK-3β signaling pathway can be regulated by miR-539-5p. In conclusion, this study provided a novel insight into the pathologic mechanism of AD by identifying that miR-539-5p plays a neuroprotective role in AD.

Synthesis, in vitro evaluation and molecular docking of a new class of indolylpropyl benzamidopiperazines as dual AChE and SERT ligands for Alzheimer's disease

During the last decade, the one drug-one target strategy has resulted to be inefficient in facing diseases with complex ethiology like Alzheimer's disease and many others. In this context, the multitarget paradigm has emerged as a promising strategy. Based on this consideration, we aim to develop novel molecules as promiscuous ligands acting in two or more targets at the same time. For such purpose, a new series of indolylpropyl-piperazinyl oxoethyl-benzamido piperazines were synthesized and evaluated as multitarget-directed drugs for the serotonin transporter (SERT) and acetylcholinesterase (AChE). The ability to decrease β-amyloid levels as well as cell toxicity of all compounds were also measured. In vitro results showed that at least four compounds displayed promising activity against SERT and AChE. Compounds 18 and 19 (IC₅₀ = 3.4 and 3.6 μM respectively) exhibited AChE inhibition profile in the same order of magnitude as donepezil (DPZ, IC₅₀ = 2.17 μM), also displaying nanomolar affinity in SERT. Moreover, compounds 17 and 24 displayed high SERT affinities (IC₅₀ = 9.2 and 1.9 nM respectively) similar to the antidepressant citalopram, and significant micromolar AChE activity at the same time. All the bioactive compounds showed a low toxicity profile in the range of concentrations studied. Molecular docking allowed us to rationalize the binding mode of the synthesized compounds in both targets. In addition, we also show that compounds 11 and 25 exhibit significant β-amyloid lowering activity in a cell-based assay, 11 (50% inhibition, 10 μM) and 25 (35% inhibition, 10 μM). These results suggest that indolylpropyl benzamidopiperazines based compounds constitute promising leads for a multitargeted approach for Alzheimer's disease.

Effect of Quercetin on PC12 Alzheimer's Disease Cell Model Induced by Aβ 25-35 and Its Mechanism Based on Sirtuin1/Nrf2/HO-1 Pathway

Objective

This study is aimed at studying the effect of quercetin on the Alzheimer disease cell model induced by Aβ_25-35 in PC12 cells and its mechanism of action.

Methods

The AD cell model was established by Aβ_25-35. Quercetin was used at different concentrations (0, 10, 20, 40, and 80 μmol/L). The morphology of cells was observed, and the effect on cell survival rate was detected by the MTT method. Cell proliferation was detected by the SRB method. The contents of LDH, SOD, MDA, GSH-Px, AChE, CAT, and T-AOC were detected by kits. The expression of sirtuin1/Nrf2/HO-1 was detected by RT-qPCR and Western blot.

Results

PC12 cells in the control group grew quickly and adhered well to the wall, most of which had extended long axons and easily grew into clusters. In the model group, cells were significantly damaged and the number of cells was significantly reduced. It was found that PC12 cells were swollen, rounded, protruding, and retracting, with reduced adherent function and floating phenomenon. Quercetin could increase the survival rate and proliferation rate of PC12 cells; reduce the levels of LDH, AChE, MDA, and HO-1 protein; and increase the levels of SOD, GSH-Px, CAT, T-AOC, sirtuin1, and Nrf2 protein.

Conclusion

Quercetin can increase the survival rate of PC12 injured by Aβ_25-35, promote cell proliferation, and antagonize the toxicity of Aβ; it also has certain neuroprotective effects. Therefore, quercetin is expected to become a drug for the treatment of AD.

The multiple sclerosis prodrome: Emerging evidence, challenges, and opportunities

A prodrome is considered an early set of signs or symptoms indicating the onset of a disease or illness. In multiple sclerosis (MS), the prodromal period is the months or years before our current, classic understanding of “MS symptom onset.” Prodromal periods are well recognized in other neurodegenerative conditions and more recently have been shown in MS. In this Viewpoint, we reflect on the emerging evidence surrounding the MS prodrome, including features that may be common across chronic inflammatory and neurodegenerative diseases. Finally, we discuss the implications for future disease prevention in MS.

Is bronchiectasis really a disease?

The definition of a disease requires that distinguishing signs and symptoms are present that are common, and that the constellation of signs and symptoms differentiate the condition from other causes. In bronchiectasis, anatomical changes, airways inflammation and airway infection are the distinguishing features that are common to this disease. However, bronchiectasis is a heterogenous disease: signs and symptoms are shared with other airway diseases, there are multiple aetiologies and certain phenotypes of bronchiectasis have distinct clinical and laboratory features that are not common to all people with bronchiectasis. Furthermore, response to therapeutic interventions in clinical trials is not uniform. The concept of bronchiectasis as a treatable trait has been suggested, but this may be too restrictive in view of the heterogeneity of bronchiectasis. It is our opinion that bronchiectasis should be defined as a disease in its own right, but one that shares several pathophysiological features and "treatable traits" with other airway diseases. These traits define the large heterogeneity in the pathogenesis and clinical features and suggest a more targeted approach to therapy.

Islet Amyloid Polypeptide: A Partner in Crime With Aβ in the Pathology of Alzheimer's Disease

Diabetes affects hundreds of millions of patients worldwide. Despite the advances in understanding the disease and therapeutic options, it remains a leading cause of death and of comorbidities globally. Islet amyloid polypeptide (IAPP), or amylin, is a hormone produced by pancreatic β-cells. It contributes to the maintenance of glucose physiological levels namely by inhibiting insulin and glucagon secretion as well as controlling adiposity and satiation. IAPP is a highly amyloidogenic polypeptide forming intracellular aggregates and amyloid structures that are associated with β-cell death. Data also suggest the relevance of unprocessed IAPP forms as seeding for amyloid buildup. Besides the known consequences of hyperamylinemia in the pancreas, evidence has also pointed out that IAPP has a pathological role in cognitive function. More specifically, IAPP was shown to impair the blood–brain barrier; it was also seen to interact and co-deposit with amyloid beta peptide (Aß), and possibly with Tau, within the brain of Alzheimer's disease (AD) patients, thereby contributing to diabetes-associated dementia. In fact, it has been suggested that AD results from a metabolic dysfunction in the brain, leading to its proposed designation as type 3 diabetes. Here, we have first provided a brief perspective on the IAPP amyloidogenic process and its role in diabetes and AD. We have then discussed the potential interventions for modulating IAPP proteotoxicity that can be explored for therapeutics. Finally, we have proposed the concept of a “diabetes brain phenotype” hypothesis in AD, which may help design future IAPP-centered drug developmentstrategies against AD.

Current and Future Treatments in Alzheimer Disease: An Update

Disease-modifying treatment strategies for Alzheimer disease (AD) are still under extensive research. Nowadays, only symptomatic treatments exist for this disease, all trying to counterbalance the neurotransmitter disturbance: 3 cholinesterase inhibitors and memantine. To block the progression of the disease, therapeutic agents are supposed to interfere with the pathogenic steps responsible for the clinical symptoms, classically including the deposition of extracellular amyloid β plaques and intracellular neurofibrillary tangle formation. Other underlying mechanisms are targeted by neuroprotective, anti-inflammatory, growth factor promotive, metabolic efficacious agents and stem cell therapies. Recent therapies have integrated multiple new features such as novel biomarkers, new neuropsychological outcomes, enrollment of earlier populations in the course of the disease, and innovative trial designs. In the near future different specific agents for every patient might be used in a “precision medicine” context, where aberrant biomarkers accompanied with a particular pattern of neuropsychological and neuroimaging findings could determine a specific treatment regimen within a customized therapeutic framework. In this review, we discuss potential disease-modifying therapies that are currently being studied and potential individualized therapeutic frameworks that can be proved beneficial for patients with AD.

Intracellular Calcium Dysregulation by the Alzheimer's Disease-Linked Protein Presenilin 2

Alzheimer's disease (AD) is the most common form of dementia. Even though most AD cases are sporadic, a small percentage is familial due to autosomal dominant mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes. AD mutations contribute to the generation of toxic amyloid β (Aβ) peptides and the formation of cerebral plaques, leading to the formulation of the amyloid cascade hypothesis for AD pathogenesis. Many drugs have been developed to inhibit this pathway but all these approaches currently failed, raising the need to find additional pathogenic mechanisms. Alterations in cellular calcium (Ca2+) signaling have also been reported as causative of neurodegeneration. Interestingly, Aβ peptides, mutated presenilin-1 (PS1), and presenilin-2 (PS2) variously lead to modifications in Ca2+ homeostasis. In this contribution, we focus on PS2, summarizing how AD-linked PS2 mutants alter multiple Ca2+ pathways and the functional consequences of this Ca2+ dysregulation in AD pathogenesis.

Misfolded proteins as a therapeutic target in Alzheimer's disease

For decades, Alzheimer's Disease (AD) was defined as a disorder of protein misfolding and aggregation. In particular, the extracellular peptide fragment: amyloid-β (Aβ), and the intracellular microtubule-associated protein: tau, were thought to initiate a neurodegenerative cascade which culminated in AD's progressive loss of memory and executive function. As such, both proteins became the focus of intense scrutiny, and served as the principal pathogenic target for hundreds of clinical trials. However, with varying efficacy, none of these investigations produced a disease-modifying therapy - offering patients with AD little recourse aside from transient, symptomatic medications. The near universal failure of clinical trials is unprecedented for a major research discipline. In part, this has motivated an increasing skepticism of the relevance of protein misfolding to AD's etiology. Several recent observations, principally the presence of significant protein pathologies in non-demented seniors, have lent credence to an apparent cursory role for Aβ and tau. Herein, we review both Aβ and tau, examining the processes from their biosynthesis to their pathogenesis and evaluate their vulnerability to medicinal intervention. We further attempt to reconcile the apparent failure of trials with the potential these targets hold. Ultimately, we seek to answer if protein misfolding is a viable platform in the pursuit of a disease-arresting strategy for AD.

New Insights Into the Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD), a common neurodegenerative disease in the elderly and the most prevalent cause of dementia, is characterized by progressive cognitive impairment. The prevalence of AD continues to increase worldwide, becoming a great healthcare challenge of the twenty-first century. In the more than 110 years since AD was discovered, many related pathogenic mechanisms have been proposed, and the most recognized hypotheses are the amyloid and tau hypotheses. However, almost all clinical trials targeting these mechanisms have not identified any effective methods to treat AD. Scientists are gradually moving away from the simple assumption, as proposed in the original amyloid hypothesis, to new theories of pathogenesis, including gamma oscillations, prion transmission, cerebral vasoconstriction, growth hormone secretagogue receptor 1α (GHSR1α)-mediated mechanism, and infection. To place these findings in context, we first reviewed the neuropathology of AD and further discussed new insights in the pathogenesis of AD.

O-GlcNAcylation as a Therapeutic Target for Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia and the number of elderly patients suffering from AD has been steadily increasing. Despite worldwide efforts to cope with this disease, little progress has been achieved with regard to identification of effective therapeutics. Thus, active research focusing on identification of new therapeutic targets of AD is ongoing. Among the new targets, post-translational modifications which modify the properties of mature proteins have gained attention. O-GlcNAcylation, a type of PTM that attaches O-linked β-N-acetylglucosamine (O-GlcNAc) to a protein, is being sought as a new target to treat AD pathologies. O-GlcNAcylation has been known to modify the two important components of AD pathological hallmarks, amyloid precursor protein, and tau protein. In addition, elevating O-GlcNAcylation levels in AD animal models has been shown to be effective in alleviating AD-associated pathology. Although studies investigating the precise mechanism of reversal of AD pathologies by targeting O-GlcNAcylation are not yet complete, it is clearly important to examine O-GlcNAcylation regulation as a target of AD therapeutics. This review highlights the mechanisms of O-GlcNAcylation and its role as a potential therapeutic target under physiological and pathological AD conditions.

Alzheimer's disease: The derailed repair hypothesis

A lot of research has been done on Alzheimer's disease, especially focused on factors like amyloid beta, ApoE and tau-protein. However, a complete theory on the disease mechanism of AD, including and connecting all known pathological elements of AD in a conceivable context and order of occurrence, is still lacking. In this article I describe a hypothesis on the entire pathophysiology of Alzheimer's disease, based on the most wellknown pathological elements in AD, filling the gaps with hypothetical mechanisms. This proposed mechanism of derailed repair starts with an insufficiently increased level of injury signalling in the axon by ApoE, DLK, APP, BACE-1, Aβ and iPLA2β, followed by an excessive repair response induced by opening of the mitochondrial permeability transition pore, release of mitochondrial CoA and activation of palmitoylation and massive endocytosis. Excessive compounds, associated with injury signalling and repair, start to accumulate, adding to axonal injury. This increased activation of the repair mechanism causes exhaustion of the repair response by lack of mitochondrial CoA. A vicious circle of increased injury signalling and insufficient repair ensues. Based on this hypothesis, I propose possible markers for early diagnosis and disease-modifying treatments for Alzheimer's disease.

Reasons for Failed Trials of Disease-Modifying Treatments for Alzheimer Disease and Their Contribution in Recent Research

Despite all scientific efforts and many protracted and expensive clinical trials, no new drug has been approved by FDA for treatment of Alzheimer disease (AD) since 2003. Indeed, more than 200 investigational programs have failed or have been abandoned in the last decade. The most probable explanations for failures of disease-modifying treatments (DMTs) for AD may include late initiation of treatments during the course of AD development, inappropriate drug dosages, erroneous selection of treatment targets, and mainly an inadequate understanding of the complex pathophysiology of AD, which may necessitate combination treatments rather than monotherapy. Clinical trials’ methodological issues have also been criticized. Drug-development research for AD is aimed to overcome these drawbacks. Preclinical and prodromal AD populations, as well as traditionally investigated populations representing all the clinical stages of AD, are included in recent trials. Systematic use of biomarkers in staging preclinical and prodromal AD and of a single primary outcome in trials of prodromal AD are regularly integrated. The application of amyloid, tau, and neurodegeneration biomarkers, including new biomarkers—such as Tau positron emission tomography, neurofilament light chain (blood and Cerebrospinal fluid (CSF) biomarker of axonal degeneration) and neurogranin (CSF biomarker of synaptic functioning)—to clinical trials allows more precise staging of AD. Additionally, use of Bayesian statistics, modifiable clinical trial designs, and clinical trial simulators enrich the trial methodology. Besides, combination therapy regimens are assessed in clinical trials. The above-mentioned diagnostic and statistical advances, which have been recently integrated in clinical trials, are relevant to the recent failures of studies of disease-modifying treatments. Their experiential rather than theoretical origins may better equip potentially successful drug-development strategies.

Highly integrated workflows for exploring cardiovascular conditions: Exemplars of precision medicine in Alzheimer's disease and aortic dissection

For precision medicine to be implemented through the lens of in silico technology, it is imperative that biophysical research workflows offer insight into treatments that are specific to a particular illness and to a particular subject. The boundaries of precision medicine can be extended using multiscale, biophysics-centred workflows that consider the fundamental underpinnings of the constituents of cells and tissues and their dynamic environments. Utilising numerical techniques that can capture the broad spectrum of biological flows within complex, deformable and permeable organs and tissues is of paramount importance when considering the core prerequisites of any state-of-the-art precision medicine pipeline. In this work, a succinct breakdown of two precision medicine pipelines developed within two Virtual Physiological Human (VPH) projects are given. The first workflow is targeted on the trajectory of Alzheimer's Disease, and caters for novel hypothesis testing through a multicompartmental poroelastic model which is integrated with a high throughput imaging workflow and subject-specific blood flow variability model. The second workflow gives rise to the patient specific exploration of Aortic Dissections via a multi-scale and compliant model, harnessing imaging, computational fluid-dynamics (CFD) and dynamic boundary conditions. Results relating to the first workflow include some core outputs of the multiporoelastic modelling framework, and the representation of peri-arterial swelling and peri-venous drainage solution fields. The latter solution fields were statistically analysed for a cohort of thirty-five subjects (stratified with respect to disease status, gender and activity level). The second workflow allowed for a better understanding of complex aortic dissection cases utilising both a rigid-wall model informed by minimal and clinically common datasets as well as a moving-wall model informed by rich datasets.

Erythrocyte membrane fluidity in mild cognitive impairment and Alzheimer's disease patients

Alzheimer's disease (AD) is the most common cause of dementia accounting for 60-70% of all demented cases and one of the leading sources of morbidity and mortality in the aging population. Most of the recent literature regards the relationship between plasma oxidative stress and AD, showing that markers of lipid peroxidation are significantly higher in AD and Mild Cognitive Impairment (MCI) patients with respect to control subjects. The increased generation of reactive oxygen species that occurs in AD may be also responsible for oxidative injury to erythrocyte membranes. Since erythrocyte membrane serves as a variable barrier to oxygen transport, changes in its stability can induce cellular hypoxia and the consequence brain tissue oxygenation. In this study, plasma oxygen radical absorbance capacity (ORAC) and erythrocyte membrane fluidity have been evaluated in control, MCI and AD patients. Moreover erythrocyte membrane acetylcholinesterase (AchE) activity has been measured in control and AD patients. Plasma ORAC significantly decreased in MCI and AD subjects with respect to the controls, while a decrease in erythrocyte membrane fluidity has been observed only in MCI patients. No significant differences were detected in erythrocyte AchE activity between control subjects and AD patients.

Therapeutic Potential of the Hsp90/Cdc37 Interaction in Neurodegenerative Diseases

Alzheimer's, Huntington's, and Parkinson's are devastating neurodegenerative diseases that are prevalent in the aging population. Patient care costs continue to rise each year, because there is currently no cure or disease modifying treatments for these diseases. Numerous efforts have been made to understand the molecular interactions governing the disease development. These efforts have revealed that the phosphorylation of proteins by kinases may play a critical role in the aggregation of disease-associated proteins, which is thought to contribute to neurodegeneration. Interestingly, a molecular chaperone complex consisting of the 90 kDa heat shock protein (Hsp90) and Cell Division Cycle 37 (Cdc37) has been shown to regulate the maturation of many of these kinases as well as regulate some disease-associated proteins directly. Thus, the Hsp90/Cdc37 complex may represent a potential drug target for regulating proteins linked to neurodegenerative diseases, through both direct and indirect interactions. Herein, we discuss the broad understanding of many Hsp90/Cdc37 pathways and how this protein complex may be a useful target to regulate the progression of neurodegenerative disease.

2-Hydroxy-N-phenylbenzamides and Their Esters Inhibit Acetylcholinesterase and Butyrylcholinesterase

The development of novel inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) represents a viable approach to alleviate Alzheimer’s disease. Thirty-six halogenated 2-hydroxy-N-phenylbenzamides (salicylanilides) with various substitution patterns and their esters with phosphorus-based acids were synthesized in yields of 72% to 92% and characterized. They were evaluated for in vitro inhibition of AChE from electric eel and BuChE from equine serum using modified Ellman’s spectrophotometric method. The benzamides exhibited a moderate inhibition of AChE with IC₅₀ values in a narrow concentration range from 33.1 to 85.8 µM. IC₅₀ values for BuChE were higher (53.5–228.4 µM). The majority of derivatives inhibit AChE more efficiently than BuChE and are comparable or superior to rivastigmine—an established cholinesterases inhibitor used in the treatment of Alzheimer’s disease. Phosphorus-based esters especially improved the activity against BuChE with 5-chloro-2-{[4-(trifluoromethyl)phenyl]carbamoyl}phenyl diethyl phosphite 5c superiority (IC₅₀ = 2.4 µM). This derivative was also the most selective inhibitor of BuChE. It caused a mixed inhibition of both cholinesterases and acted as a pseudo-irreversible inhibitor. Several structure-activity relationships were identified, e.g., favouring esters and benzamides obtained from 5-halogenosalicylic acids and polyhalogenated anilines. Both 2-hydroxy-N-phenylbenzamides and esters share convenient physicochemical properties for blood-brain-barrier penetration and thus central nervous system delivery.

The Rat Prefrontal-Cortex Transcriptome: Effects of Aging and Sporadic Alzheimer's Disease-Like Pathology

Alzheimer's disease (AD) is the most widespread late-life dementia and involves the prefrontal cortex, a vulnerable brain region implicated in memory, emotion, cognition, and decision-making behavior. To understand the molecular differences between the effects of aging and AD on the prefrontal cortex, this study characterized the age-dependent changes in gene expression in Wistar rats (control) and OXYS rats (rodents that simulate key characteristics of sporadic AD) using RNA sequencing. We found that major altered biological processes during aging in Wistar rats were associated with immune processes. Gene expression changes during development of AD-like pathology as well as at the preclinical stage were related to neuronal plasticity, catalytic activity, lipid and immune processes, and mitochondria. A comparison of genes between data sets "OXYS rats" and "human AD" revealed similarity in expression alterations of genes related primarily to mitochondrial function; immune, endocrine, and circulatory systems; signal transduction; neuronal and synaptic processes; hypoxia; and apoptosis. Expression changes in mitochondrial processes identified in OXYS rats by RNA sequencing were confirmed by ultrastructural neuronal organelle alterations and low activity of respiratory chain complexes I, IV, and V in cortical mitochondria, suggesting that mitochondrial dysfunction appears to mediate or possibly even initiate the development of AD.

TGF-β Signaling in Cellular Senescence and Aging-Related Pathology

Aging is broadly defined as the functional decline that occurs in all body systems. The accumulation of senescent cells is considered a hallmark of aging and thought to contribute to the aging pathologies. Transforming growth factor-β (TGF-β) is a pleiotropic cytokine that regulates a myriad of cellular processes and has important roles in embryonic development, physiological tissue homeostasis, and various pathological conditions. TGF-β exerts potent growth inhibitory activities in various cell types, and multiple growth regulatory mechanisms have reportedly been linked to the phenotypes of cellular senescence and stem cell aging in previous studies. In addition, accumulated evidence has indicated a multifaceted association between TGF-β signaling and aging-associated disorders, including Alzheimer’s disease, muscle atrophy, and obesity. The findings regarding these diseases suggest that the impairment of TGF-β signaling in certain cell types and the upregulation of TGF-β ligands contribute to cell degeneration, tissue fibrosis, inflammation, decreased regeneration capacity, and metabolic malfunction. While the biological roles of TGF-β depend highly on cell types and cellular contexts, aging-associated changes are an important additional context which warrants further investigation to better understand the involvement in various diseases and develop therapeutic options. The present review summarizes the relationships between TGF-β signaling and cellular senescence, stem cell aging, and aging-related diseases.

Eye tracking - The overlooked method to measure cognition in neurodegeneration?

Eye tracking (ET) studies are becoming increasingly popular due to rapid methodological and technological advances as well as the development of cost efficient and portable eye trackers. Although historically ET has been mostly employed in psychophysics or developmental cognition studies, there is also promising scope to use ET for movement disorders and measuring cognitive processes in neurodegeneration. Particularly, ET can be a powerful tool for cognitive and neuropsychological assessments of patients with pathologies affecting motor and verbal abilities, as tasks can be adapted without requiring motor (except eye movements) or verbal responses. In this review, we will examine the existing evidence of ET methods in neurodegenerative conditions and its potential clinical impact for cognitive assessment. We highlight that current evidence for ET is mostly focused on diagnostics of cognitive impairments in neurodegenerative disorders, where it is debatable whether it has any more sensitivity or specificity than existing cognitive assessments. By contrast, there is currently a lack of ET studies in more advanced disease stages, when patients' motor and verbal functions can be significantly affected, and standard cognitive assessments are challenging or often not possible. We conclude that ET is a promising method not only for cognitive diagnostics but more importantly, for potential cognitive disease tracking in progressive neurodegenerative conditions.

Neuropsychological latent classes at enrollment and postmortem neuropathology

INTRODUCTION

We classified individuals based on their baseline performance on cognitive measures and investigated the association between cognitive classifications and neuropathological findings ∼7 years later, as an external validator.

METHODS

Brain autopsies of 779 decedents were examined. Baseline latent class analysis on 10 neuropsychological measures was previously assigned: mixed-domains impairment (n = 39, 5%), memory-specific impairment (n = 210, 27%), frontal impairment (n = 113, 14.5%), average cognition (n = 360, 46.2%), and superior cognition (n = 57, 7.3%). Linear regressions and risks ratios were used to examine the relation of latent class assignment at enrollment with neuropathological indices.

RESULTS

Amyloid β, tau, and transactive response DNA-binding protein 43 were associated with mixed-domains impairment and memory-specific impairment classes ∼7 years before death. Moderate arteriolosclerosis was associated with membership in the frontal impairment class.

DISCUSSION

Our findings support the use of latent class models that incorporate more comprehensive neuropsychological measures to classify cognitive impairment.

Risk classification for conversion from mild cognitive impairment to Alzheimer's disease in primary care

There is a pressing need to identify individuals at high risk of conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD) based on available repeated cognitive measures in primary care. Using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), we applied a joint latent class mixed model (JLCM) to derive a 3-class solution: low risk (72.65%), medium risk (20.41%) and high risk (6.94%). In the low-risk group, individuals with lower daily activity and ApoEε4 carriers were at greater risk of conversion from MCI to AD. In the medium-risk group, being female, single, and an ApoEε4 carrier increased risk of conversion to AD. In the high-risk group, individuals with lower education level and single individuals were at greater risk of conversion to AD. Individual dynamic prediction for conversion from MCI to AD after 10 years was derived. Accurate identification of conversion from MCI to AD contributes to earlier close monitoring, appropriate management, and targeted interventions. Thereby, it can reduce avoidable hospitalizations for the high-risk MCI population. Moreover, it can avoid expensive follow-up tests that may provoke unnecessary anxiety for low-risk individuals and their families.

Layer-Wise Relevance Propagation for Explaining Deep Neural Network Decisions in MRI-Based Alzheimer's Disease Classification

Deep neural networks have led to state-of-the-art results in many medical imaging tasks including Alzheimer's disease (AD) detection based on structural magnetic resonance imaging (MRI) data. However, the network decisions are often perceived as being highly non-transparent, making it difficult to apply these algorithms in clinical routine. In this study, we propose using layer-wise relevance propagation (LRP) to visualize convolutional neural network decisions for AD based on MRI data. Similarly to other visualization methods, LRP produces a heatmap in the input space indicating the importance/relevance of each voxel contributing to the final classification outcome. In contrast to susceptibility maps produced by guided backpropagation ("Which change in voxels would change the outcome most?"), the LRP method is able to directly highlight positive contributions to the network classification in the input space. In particular, we show that (1) the LRP method is very specific for individuals ("Why does this person have AD?") with high inter-patient variability, (2) there is very little relevance for AD in healthy controls and (3) areas that exhibit a lot of relevance correlate well with what is known from literature. To quantify the latter, we compute size-corrected metrics of the summed relevance per brain area, e.g., relevance density or relevance gain. Although these metrics produce very individual "fingerprints" of relevance patterns for AD patients, a lot of importance is put on areas in the temporal lobe including the hippocampus. After discussing several limitations such as sensitivity toward the underlying model and computation parameters, we conclude that LRP might have a high potential to assist clinicians in explaining neural network decisions for diagnosing AD (and potentially other diseases) based on structural MRI data.

Role of Resveratrol and Selenium on Oxidative Stress and Expression of Antioxidant and Anti-Aging Genes in Immortalized Lymphocytes from Alzheimer's Disease Patients

Oxidative damage is involved in the pathophysiology of age-related ailments, including Alzheimer's disease (AD). Studies have shown that the brain tissue and also lymphocytes from AD patients present increased oxidative stress compared to healthy controls (HCs). Here, we use lymphoblastoid cell lines (LCLs) from AD patients and HCs to investigate the role of resveratrol (RV) and selenium (Se) in the reduction of reactive oxygen species (ROS) generated after an oxidative injury. We also studied whether these compounds elicited expression changes in genes involved in the antioxidant cell response and other aging-related mechanisms. AD LCLs showed higher ROS levels than those from HCs in response to H2O2 and FeSO4 oxidative insults. RV triggered a protective response against ROS under control and oxidizing conditions, whereas Se exerted antioxidant effects only in AD LCLs under oxidizing conditions. RV increased the expression of genes encoding known antioxidants (catalase, copper chaperone for superoxide dismutase 1, glutathione S-transferase zeta 1) and anti-aging factors (sirtuin 1 and sirtuin 3) in both AD and HC LCLs. Our findings support RV as a candidate for inducing resilience and protection against AD, and reinforce the value of LCLs as a feasible peripheral cell model for understanding the protective mechanisms of nutraceuticals against oxidative stress in aging and AD.

Elevation of Plasma Amyloid-β Level is More Significant in Early Stage of Cognitive Impairment: A Population-Based Cross-Sectional Study

BACKGROUND

Aggregation and deposition of amyloid-β (Aβ) in the brain is the main pathological change of Alzheimer's disease (AD). Decreased Aβ42 in the cerebrospinal fluid has been confirmed as a biomarker of AD; however, the relationship between plasma Aβ and cognitive impairment is currently unclear.

OBJECTIVE

The aim was to explore the relationship between plasma Aβ and cognitive impairment in a cross-sectional study.

METHODS

A total of 1,314 subjects (age above 40) from a village in the suburbs of Xi'an, China were enrolled between October 8, 2014 and March 30, 2015. A validated Chinese version of the Mini-Mental State Examination and neuropsychological battery were used to assess cognition. Levels of plasma Aβ42 and Aβ40 were tested using commercial enzyme-linked immunosorbent assay. Relationship of plasma Aβ and cognitive impairment was analyzed using logistic regression analysis.

RESULTS

Of the enrolled subjects, 1,180 (89.80%) had normal cognition, 85 (6.47%) had possible cognitive impairment and 49 (3.73%) had probable cognitive impairment. Logistic regression analysis showed that the Aβ42/Aβ40 ratio (OR = 4.042, 95% CI: 1.248-11.098, p = 0.012) and plasma Aβ42 (OR = 1.036, 95% CI: 1.003-1.071, p = 0.031) was higher in the possible cognitive impairment than that in the normal cognition group. Furthermore, the plasma Aβ42/Aβ40 ratio was higher in the possible cognitive impairment group than that in the probable cognitive impairment group (OR = 0.029, 95% CI: 0.002-0.450, p = 0.011).

CONCLUSIONS

Levels of plasma Aβ42 and Aβ42/Aβ40 ratio were elevated in patients with possible cognitive impairment, indicating that plasma Aβ42 and Aβ42/Aβ40 ratio increases may be more pronounced in early stage of cognitive impairment.

The long-non-coding RNA NEAT1 is a novel target for Alzheimer's disease progression via miR-124/BACE1 axis

OBJECTIVES

Long-non-coding RNAs (lncRNAs) have been involved in central nervous system recently. A number of studies have reported that lncRNA NEAT1 exerts critical roles in neurodegenerative disorder. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) has been reported to exert function in the accumulation of amyloid-β (Aβ). Moreover, BACE1 acts as a target of miR-124 in the progression of AD. So far, the biological role and underlying mechanisms of NEAT1 and miR-124 in AD remains elusive.

METHODS

The relative NEAT1 and miR-124 expression was examined by qRT-PCR in the tissues and cells line of AD. Cell apoptosis was examined by FACS. Luciferase reporter assay was performed to verify that miR-124 is a direct target of NEAT1, and BACE1 is a downstream target of miR-124. qRT-PCR and western blot analysis were also performed to determinate the BACE1 and the phosphorylation of tau protein.

RESULTS

NEAT1 was notably up-regulated and miR-124 was remarkably down-regulated in AD mouse model. Knockdown of NEAT1 or overexpression of miR-124 showed the protective effects on cellular AD model induced by Aβ. Moreover, miR-124 expression could be up- and down-regulated by suppression or overexpression of NEAT1, respectively. In addition, the expression of BACE1 was the potential functional target of miR-124. These findings suggested that NEAT1 might play a vital role in the development of AD by regulating miR-124/BACE1 axis.

DISCUSSION

The present study showed that NEAT1 worked as a regulating factor to promote the development of AD via modulating miR-124/BACE1 axis, which might be considered as a novel target in AD treatment.

CRMP2-derived peptide ST2-104 (R9-CBD3) protects SH-SY5Y neuroblastoma cells against Aβ25-35-induced neurotoxicity by inhibiting the pCRMP2/NMDAR2B signaling pathway

Collapsin response mediator protein 2 (CRMP2),by regulating voltage-gated calcium channel activity, is a crucial regulator of neuronal excitability. Hyperphosphorylation of CRMP2 has been reported in brains of Alzheimer's disease (AD) patients and other neurodegenerative diseases. CRMP2 acting on N-methyl-d-aspartate receptors (NMDARs) may contribute to AD pathology. A short peptide from CRMP2, designated the Ca²⁺ channel-binding domain 3 (CBD3) peptide, has recently emerged as a Ca²⁺ channel blocker that exerts neuroprotective effects in traumatic brain injury and cerebral ischemia by disrupting pCRMP2/NMDAR interaction to inhibit calcium influx. ST2-104, a nona-arginine (R9)-conjugated CBD3 peptide derived from CRMP2, exerts a beneficial effect on neuropathic pain; however, the effect of ST2-104 on AD and its mechanism of action have not been studied. In this study we investigated the effects of ST2-104 on SH-SY5Y neuroblastoma cells stimulated by Aβ_25-35. To induce neurotoxicity, SH-SY5Y cells were incubated with Aβ_25-35, the shortest toxic fragment of Aβ. CRMP2 expression was manipulated by knockdown or overexpression of CRMP2 before ST2-104 treatment to further explore if the pCRMP2/NMDAR2B signaling pathway is involved in the action of the ST2-104 peptide. The results show that ST2-104 significantly enhanced cell viability, inhibited cell apoptosis, decreased LDH release, suppressed the expression of the pCRMP2 protein, disrupted pCRMP2/NMDAR2B interaction, inhibited Aβ_25-35-induced NMDAR currents, and decreased intracellular Ca²⁺ levels. The effects of ST2-104 was abolished by overexpression of CRMP2 and intensified by knockdown of CRMP2 in SH-SY5Y cells. Taken together, our results support ST2-104 as a possible biologic therapeutic in the face of Aβ_25-35-induced injury via the inhibition of the pCRMP2/NMDAR2B signaling pathway.

Alzheimer’s disease: An overview of the current treatments

Alzheimer’s disease (AD) affects millions of people around the world and although there are treatments that help control symptoms and slow down the progress of the disease, there is still no cure. Current treatments include three acetylcholine inhibitors, a glutamate inhibitor and a combination of the two. Due to the failure of hundreds of clinical trials with monotherapies, multitarget treatments are currently being investigated that consider both brain and peripheral factors. Gene therapy is one of the most promising therapies to treat and prevent the development of AD. Nowadays, there is no available medical treatment based on gene therapy to treat AD; however, there are treatments in phase 1 and phase 2 clinical trials with promising results. In this review, we will focus on the most important gene therapy treatments, CERE-110 (adeno-associated virus AAV2-Nerve Growth Factor), Intracerebral AAV gene delivery of APOE2 and gene therapy using PPARγ-coactivator-1α(PGC-1α)

Evaluation of APOE Genotype and Vascular Risk Factors As Prognostic and Risk Factors for Alzheimer's Disease and Their Influence On Age of Symptoms Onset

BACKGROUND

Alzheimer's disease (AD), the most common cause of dementia, is evolving to become a threatening epidemy of the 21^st century. Only 21% of the predicted number of AD patients in Macedonia have been diagnosed and treated, which means that almost 80% are underdiagnosed or misdiagnosed. Apolipoprotein E gene (APOE) is recognised as the strongest genetic risk factor for sporadic AD. Whether and when Alzheimer's disease develops, depends on the very complex interaction between genetic and modifiable risk factors. It has been known that vascular factors like hypertension, diabetes mellitus, hypercholesterolemia and obesity increase the risk of developing both AD, vascular dementia and mixed AD and vascular pathology.

AIM

This study aims to evaluate the influence of APOEε4 allele presence and modifiable vascular risk factors (hypertension, diabetes mellitus and dyslipidemia) as prognostic and risk factors for AD and their influence on the age of onset of AD symptoms among 144 AD patients from Macedonia.

MATERIAL AND METHODS

Study group of a total of 144 patients diagnosed with AD was evaluated. APOE genotyping was performed using APOE haplotype-specific sequence specific-primer (SSP)-PCR (Polymerase Chain Reaction) methodology. The non-standardized questionnaire was used to obtain information about demographics, lifestyle and modifiable risk factors that could influence disease onset and phenotype.

RESULTS

Statistically significant association was found between the presences of APOEε4 allele in AD group versus controls. The presence of APOEε4 allele increases the risk of developing AD in a 3-fold manner. The average age of disease onset in the ε4 carrier group was 67.2 ± 8.3 and in the ε4 non-carrier group 69.7 ± 9.4. This confirms that the presence of APOEε4 allele shifts towards earlier disease onset, though the difference is not statistically significant. Out of the vascular risk factors, only hypertension was significantly associated with earlier AD onset. Out of total 144 patients, in 22.9% the first symptom onset was before the age of 65, that can be considered as early onset Alzheimer's Disease (EOAD), which is much higher than 5% for EOAD as most of the studies report.

CONCLUSIONS

The average age of disease onset of 68.4 years could be considered earlier than the average age of AD onset worldwide. Out of all the vascular risk factors analysed in this study, only hypertension and dyslipidemia were found to significantly increase the risk for developing AD and only the presence of hypertension influences the age of onset, shifting towards earlier disease onset. Public awareness campaigns should be organised to influence general population knowledge about Alzheimer's disease, early recognition and the influence of modifiable vascular risk factors.

Novel Approaches for the Treatment of Alzheimer's and Parkinson's Disease

Neurodegenerative disorders affect around one billion people worldwide. They can arise from a combination of genomic, epigenomic, metabolic, and environmental factors. Aging is the leading risk factor for most chronic illnesses of old age, including Alzheimer’s and Parkinson’s diseases. A progressive neurodegenerative process and neuroinflammation occur, and no current therapies can prevent, slow, or halt disease progression. To date, no novel disease-modifying therapies have been shown to provide significant benefit for patients who suffer from these devastating disorders. Therefore, early diagnosis and the discovery of new targets and novel therapies are of upmost importance. Neurodegenerative diseases, like in other age-related disorders, the progression of pathology begins many years before the onset of symptoms. Many efforts in this field have led to the conclusion that exits some similar events among these diseases that can explain why the aging brain is so vulnerable to suffer neurodegenerative diseases. This article reviews the current knowledge about these diseases by summarizing the most common features of major neurodegenerative disorders, their causes and consequences, and the proposed novel therapeutic approaches.

Spore powder of Ganoderma lucidum for Alzheimer's disease: A protocol for systematic review

BACKGROUND

Previous studies have reported that spore powder of Ganoderma lucidum (SPGL) may be effective for the treatment of Alzheimer's disease (AD). However, its efficacy is still inconclusive. Thus, this systematic review will aim to assess its efficacy and safety for AD.

METHODS

We will search the electronic databases of Cochrane Central Register of Controlled Trials, EMBASE, MEDILINE, the Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, and Chinese Biomedical Literature Database to assess the efficacy and safety of SPGL for patients with AD from their inceptions to the present. All case-control studies and randomized controlled trials will be considered for inclusion in this study. Two review authors will independently perform the study selection, data extraction, and risk of bias evaluation.

RESULTS

The primary outcome includes the cognitive status for patients. The secondary outcomes consist of the quality of life, AD symptoms, and adverse events.

CONCLUSIONS

This systematic review will present the existing evidence for the efficacy and safety of SPGL for treating patients with AD.

DISSEMINATION AND ETHICS

The results of this systematic review will be disseminated by through peer-reviewed journals. It does not needs ethic approval, because it does not involve individual patient data.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019119426.

Late-onset Alzheimer Disease

PURPOSE OF REVIEW

Alzheimer disease (AD) is the most common cause of late-onset dementia. This article describes the epidemiology, genetic and environmental risk factors, clinical diagnosis, biomarkers, and treatment of late-onset AD, defined by age of onset of 65 years or older.

RECENT FINDINGS

An estimated 5.7 million Americans are living with AD dementia, with the number of affected individuals growing rapidly because of an aging population. Vascular risk factors, sleep disorders, and traumatic brain injury are associated with an increased risk of AD, while increased cognitive and physical activity throughout the lifespan reduce the risk of disease. The primary genetic risk factor for late-onset AD is the apolipoprotein E (APOE) ε4 allele. AD typically presents with early and prominent episodic memory loss, although this clinical syndrome is neither sensitive nor specific for underlying AD neuropathology. Emerging CSF and imaging biomarkers can now detect the key neuropathologic features of the disease (amyloid plaques, neurofibrillary tangles, and neurodegeneration) in living people, allowing for characterization of patients based on biological measures. A comprehensive treatment plan for AD includes use of symptomatic medications, optimal treatment of comorbid conditions and neuropsychiatric symptoms, counseling about safety and future planning, and referrals to community resources.

SUMMARY

AD is very common in older neurologic patients. Neurologists should set the standard for the diagnosis and care of patients with AD and should be familiar with emerging biomarkers that have transformed AD research and are primed to enter the clinical arena.

Going beyond the mean: Intraindividual variability of cognitive performance in prodromal and early neurodegenerative disorders

OBJECTIVE

Intraindividual variability (IIV), generally defined as short-term variations in behavior, has been proposed as a sign of subtle early impairment in neurodegenerative disorders, presumably associated with the disintegration of neuronal network connectivity. We aim to provide a review of IIV as a sensitive cognitive marker in prodromal neurodegenerative disorders.

METHOD

A narrative review focusing not only on theoretical and methodological definitions, including an overview on the neural correlates of IIV, but mainly on results from population-based and clinical-based studies on the role of IIV as a reliable predictor of mild cognitive impairment (MCI) and conversion to dementia in neurodegenerative disorders, mostly Alzheimer's and Parkinson's disease.

RESULTS

Most studies focus on MCI and Alzheimer's disease and demonstrate that IIV is a reliable cognitive marker. IIV is partly more sensitive than mean performance in the prediction of cognitive impairment or progressive deterioration and is independent of socio-demographic variables and disease mediators (e.g., genetic susceptibility). Neuroimaging data, mostly from healthy subjects, suggest a relationship between IIV and dysfunction of the default mode network, presumably mediated by white matter disintegration in frontal and parietal areas.

CONCLUSIONS

IIV measures may provide valuable information about diagnosis and progression in prodromal stages of neurodegenerative disorders. Thus, further conceptual and methodological clarifications are needed to justify the inclusion of IIV as a sensible cognitive marker in routine clinical neuropsychological assessment.