Alzheimer disease immunotherapeutics: then and now

Hotspots and trends of microglia in Alzheimer's disease: a bibliometric analysis during 2000-2022

BACKGROUND

Alzheimer's disease is one common type of dementia. Numerous studies have suggested a correlation between Alzheimer's disease and inflammation. Microglia mainly participate in the inflammatory response in the brain. Currently, ample evidence has shown that microglia are closely related to the occurrence and development of Alzheimer's disease.

OBJECTIVE

We opted for bibliometric analysis to comprehensively summarize the advancements in the study of microglia in Alzheimer's disease, aiming to provide researchers with current trends and future research directions.

METHODS

All articles and reviews pertaining to microglia in Alzheimer's disease from 2000 to 2022 were downloaded through Web of Science Core Collection. The results were subjected to bibliometric analysis using VOSviewer 1.6.18 and CiteSpace 6.1 R2.

RESULTS

Overall, 7449 publications were included. The number of publications was increasing yearly. The United States has published the most publications. Harvard Medical School has published the most papers of all institutions. Journal of Alzheimer's Disease and Journal of Neuroscience were the journals with the most studies and the most commonly cited, respectively. Mt Heneka is the author with the highest productivity and co-citation. After analysis, the most common keywords are neuroinflammation, amyloid-beta, inflammation, neurodegeneration. Gut microbiota, extracellular vesicle, dysfunction and meta-analysis are the hotspots of research at the present stage and are likely to continue.

CONCLUSION

NLRP3 inflammasome, TREM2, gut microbiota, mitochondrial dysfunction, exosomes are research hotspots. The relationship between microglia-mediated neuroinflammation and Alzheimer's disease have been the focus of current research and the development trend of future research.

Kaempferol as a therapeutic agent in Alzheimer's disease: Evidence from preclinical studies

BACKGROUND

Alzheimer's disease (AD) is the most common type of dementia and seriously affects human life and health. Kaempferol (KMP) is a common flavonoid, that is mainly derived from the rhizomes of Kaempferol galanga L. and is widely found in various fruits and vegetables. Previous studies have suggested that KMP has multiple pharmacological activities. However, the anti-AD mechanism of KMP has not been elucidated.

METHODS

This systematic review aims to summarize the existing preclinical experiments on KMP, further confirm the therapeutic effect of KMP in an AD model, and summarize the possible mechanism by which KMP exerts anti-AD effects. Electronic databases, including PubMed, China National Knowledge Infrastructure (CNKI), Baidu Academic, and Wanfang, were searched using the keywords of 'Kaempferol,' 'KMP,' 'pharmacology,' and 'Alzheimer's disease'.

RESULTS

We evaluated the reliability of the 12 included studies, and the results showed that the anti-AD mechanism of KMP was reliable and that the prospect of KMP in the treatment of cognitive impairment was promising. We comprehensively assessed the neuroprotective effects of KMP in in vivo and in vitro models of AD. These studies shown that KMP ameliorated AD through several mechanisms, including its antioxidant, anti-inflammatory, anti-apoptotic, and anti-acetylcholinesterase effects.

CONCLUSION

KMP may exert anti-AD effects through various mechanisms and is a potential drug with broad prospects for the treatment of AD.

Pathogenesis, Animal Models, and Drug Discovery of Alzheimer's Disease

Alzheimer's disease (AD), the most common cause of dementia, is a chronic neurodegenerative disease induced by multiple factors. The high incidence and the aging of the global population make it a growing global health concern with huge implications for individuals and society. The clinical manifestations are progressive cognitive dysfunction and lack of behavioral ability, which not only seriously affect the health and quality of life of the elderly, but also bring a heavy burden to the family and society. Unfortunately, almost all the drugs targeting the classical pathogenesis have not achieved satisfactory clinical effects in the past two decades. Therefore, the present review provides more novel ideas on the complex pathophysiological mechanisms of AD, including classical pathogenesis and a variety of possible pathogenesis that have been proposed in recent years. It will be helpful to find out the key target and the effect pathway of potential drugs and mechanisms for the prevention and treatment of AD. In addition, the common animal models in AD research are outlined and we examine their prospect for the future. Finally, Phase I, II, III, and IV randomized clinical trials or on the market of drugs for AD treatment were searched in online databases (Drug Bank Online 5.0, the U.S. National Library of Medicine, and Alzforum). Therefore, this review may also provide useful information in the research and development of new AD-based drugs.

News about Therapies of Alzheimer’s Disease: Extracellular Vesicles from Stem Cells Exhibit Advantages Compared to Other Treatments

Upon its discovery, Alzheimer’s, the neurodegenerative disease that affects many millions of patients in the world, remained without an effective therapy. The first drugs, made available near the end of last century, induced some effects, which remained only marginal. More promising effects are now present, induced by two approaches. Blockers of the enzyme BACE-1 induce, in neurons and glial cells, decreased levels of Aβ, the key peptide of the Alzheimer’s disease. If administered at early AD steps, the BACE-1 blockers preclude further development of the disease. However, they have no effect on established, irreversible lesions. The extracellular vesicles secreted by mesenchymal stem cells induce therapy effects analogous, but more convenient, than the effects of their original cells. After their specific fusion to target cells, the action of these vesicles depends on their ensuing release of cargo molecules, such as proteins and many miRNAs, active primarily on the cell cytoplasm. Operationally, these vesicles exhibit numerous advantages: they exclude, by their accurate selection, the heterogeneity of the original cells; exhibit molecular specificity due to their engineering and drug accumulation; and induce effective actions, mediated by variable concentrations of factors and molecules and by activation of signaling cascades. Their strength is reinforced by their combination with various factors and processes. The recent molecular and operations changes, induced especially by the stem cell target cells, result in encouraging and important improvement of the disease. Their further development is expected in the near future.

The Role of Medical Acupuncture Therapy in Alzheimer's Disease

Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by memory deficits and other cognitive disorders, which can be accompanied by personality changes. Long-term use of medications available to treat AD today have a variety of side-effects. Acupuncture, as a nonpharmacologic therapeutic modality providing stimulation at acupuncture points, using filiform needles, has been widely tested and used to manage of AD and can be a therapeutic option, considering its effectiveness and lack of side-effects. Methods: This literature review examines the role of acupuncture in AD treatment. Results: Acupuncture can ameliorate AD symptoms through decreasing amyloid-β protein, reducing neuroinflammation, enhancing the antioxidant system, improving neurogenesis, enhancing prosurvival protein, reducing proapoptotic protein, and regulating brain energy metabolism. Conclusions: According to various research findings, acupuncture may be a therapeutic choice for addressing AD that avoids the long-term side-effects caused by medical therapy.

High-Sensitivity and Trace-Amount Specimen Electrochemical Sensors for Exploring the Levels of β-Amyloid in Human Blood and Tears

As the occurrence of Alzheimer's disease (AD) has increased, the detection and treatment of AD have become global social issues. Effective early detection and wide-range screening of AD allow patients to gain early control and delay brain degeneration. For these reasons, we choose electrochemical sensors to complete the detection task. Although bio-electrochemical technology for antibody and antigen sensing is not a new technology, considering the scarcity of tear samples for dementia and since the existing AD detection techniques are highly invasive and expensive for subjects, we have to use the traditional detection techniques for the early screening of Alzheimer's disease via trace-amount specimens. An AD-related protein in the eye is thought to be an important biomarker for early detection. To carry out detection using tear samples as a test specimens, a tear collection device was developed in this study that extracted 10 μL of tear fluid from a tear Schirmer strip. In this research, we distinguished healthy people in different age groups and detect Aβ in both tear and blood samples. We developed a biosensor, which could detect Aβ in tear specimen from 1 to 100 pg/mL. Also, this biosensor is inexpensive, disposable, and easy to use. In our result, the concentration of Aβ in tears was approximately 10 times more than that in blood. This study demonstrates the feasibility and prospects of future screening for AD-associated biomarkers by a dynamic comparison between blood and tears.

Response Surface Study on Molecular Docking Simulations of Citalopram and Donepezil as Potent CNS Drugs

Computer-aided drug design provides broad structural modifications to evolving bioactive molecules without an immediate requirement to observe synthetic restraints or tedious protocols. Subsequently, the most promising guidelines with regard to synthetic and biological resources may be focused on upcoming steps. Molecular docking is common in-silico drug design techniques since it predicts ligand-receptor interaction modes and associated binding affinities. Current docking simulations suffer serious constraints in estimating accurate ligand-receptor binding affinities despite several advantages and historical results. Response surface method (RSM) is an efficient statistical approach for modeling and optimization of various pharmaceutical systems. With the aim of unveiling the full potential of RSM in optimizing molecular docking simulations, this study particularly focused on binding affinity prediction of citalopram-serotonin transporter (SERT) and donepezil-acetyl cholinesterase (AChE) complexes. For this purpose, Box-Behnken design of experiments (DOE) was used to develop a trial matrix for simultaneous variations of AutoDock4.2 driven binding affinity data with selected factor levels. Responses of all docking trials were considered as estimated protein inhibition constants with regard to validated data for each drug. The output matrix was subjected to statistical analysis and constructing polynomial quadratic models. Numerical optimization steps to attain ideal docking accuracies revealed that more accurate results might be envisaged through the best combination of factor levels and considering factor interactions. Results of the current study indicated that the application of RSM in molecular docking simulations might lead to optimized docking protocols with more stable estimates of ligand-target interactions and hence better correlation of in-silico in-vitro data.

Verum- versus Sham-Acupuncture on Alzheimer's Disease (AD) in Animal Models: A Preclinical Systematic Review and Meta-Analysis

BACKGROUND

Alzheimer's disease (AD) is a common health condition affecting senile people and leads to severe cognitive dysfunctions. Acupuncture has been shown to be a possible alternative natural remedy for AD in some animal studies.

OBJECTIVE

To perform a systematic review to identify the effect of verum-acupuncture compared with sham-acupuncture on learning and memory performance among animal models of AD.

METHODS

Experimental animal studies of treating AD via verum- and sham- acupuncture were searched in nine electronic databases, including Sciverse ScienceDirect, PubMed, Springer, Ebsco Medline, AMED, EMBASE (Elsevier), Scopus (Elsevier), PsycINFO (ProQuest), and OVID from the dates of the databases' inception to June 2019. The Morris water maze test was considered as an outcome measure. The software Revman 5.3 and Stata 16.0 were used to conduct the meta-analysis. Heterogeneity was examined by using I2 statistics. The publication bias was assessed via Begg's test by Stata 16.0.

RESULTS

Twelve studies involving 229 animals met the inclusion criteria. Most of the studies had a moderate quality according to SYRCLE's risk of bias tool for animal studies. The results of the meta-analysis indicated that verum-acupuncture could reduce the escape latency (MD = -12.90, 95% CI (-17.08, -8.71), p < 0.001) and increase the time spent in the original platform quadrant (MD = 7.28, 95% CI (4.23, 10.33), p < 0.001) and frequency of the crossing former platform (MD = 2.01, 95% CI (1.53, 2.50), p < 0.001) compared with the sham-acupuncture.

CONCLUSIONS

Acupuncture is effective in improving cognitive functions in AD animal models, and this benefit is more than just a placebo effect. Further clinical trials are needed to confirm the findings.

The role of myelin damage in Alzheimer's disease pathology

Although Alois Alzheimer described myelin disruption in Alzheimer's disease (AD) as early as in 1911, his observation has escaped the attention of researchers since that time. Alzheimer's disease has been mainly considered as a grey matter disorder; nevertheless, recent evidence suggests that myelin impairment may play an important role in AD pathology. Classical neuropathological changes in AD, e.g. the accumulation of aggregated Aβ 42 and the presence of neurofibrillary tangles, are responsible for neuronal loss, but they may also induce death of oligodendrocytes and myelin damage. There is also evidence that myelin pathology may even precede Aβ and tau pathologies in AD. The state of the art does not allow us to determine whether myelin damage is a primary or a secondary injury in AD subjects. The article presents an overview of current knowledge on the role of myelin in AD pathology and its interactions with Aβ and tau pathologies.

Therapeutic Potential of Amniotic Fluid Derived Mesenchymal Stem Cells Based on their Differentiation Capacity and Immunomodulatory Properties

BACKGROUND

Amniotic Fluid Derived Mesenchymal Stem Cells (AF-MSCs) are adult, fibroblast- like, self-renewable, multipotent stem cells. During the last decade, the therapeutic potential of AF-MSCs, based on their huge differentiation capacity and immunomodulatory characteristics, has been extensively explored in animal models of degenerative and inflammatory diseases.

OBJECTIVE

In order to describe molecular mechanisms responsible for the therapeutic effects of AFMSCs, we summarized current knowledge about phenotype, differentiation potential and immunosuppressive properties of AF-MSCs.

METHODS

An extensive literature review was carried out in March 2018 across several databases (MEDLINE, EMBASE, Google Scholar), from 1990 to present. Keywords used in the selection were: "amniotic fluid derived mesenchymal stem cells", "cell-therapy", "degenerative diseases", "inflammatory diseases", "regeneration", "immunosuppression". Studies that emphasized molecular and cellular mechanisms responsible for AF-MSC-based therapy were analyzed in this review.

RESULTS

AF-MSCs have huge differentiation and immunosuppressive potential. AF-MSCs are capable of generating cells of mesodermal origin (chondrocytes, osteocytes and adipocytes), neural cells, hepatocytes, alveolar epithelial cells, insulin-producing cells, cardiomyocytes and germ cells. AF-MSCs, in juxtacrine or paracrine manner, regulate proliferation, activation and effector function of immune cells. Due to their huge differentiation capacity and immunosuppressive characteristic, transplantation of AFMSCs showed beneficent effects in animal models of degenerative and inflammatory diseases of nervous, respiratory, urogenital, cardiovascular and gastrointestinal system.

CONCLUSION

Considering the fact that amniotic fluid is obtained through routine prenatal diagnosis, with minimal invasive procedure and without ethical concerns, AF-MSCs represents a valuable source for cell-based therapy of organ-specific or systemic degenerative and inflammatory diseases.

Stem cell therapy in Alzheimer's disease: possible benefits and limiting drawbacks

Alzheimer's disease (AD) is the sixth leading cause of death globally and the main reason for dementia in elderly people. AD is a long-term and progressive neurodegenerative disorder that steadily worsens memory and communicating skills eventually leads to a disabled person of performing simple daily tasks. Unfortunately, numerous clinical trials exploring new therapeutic drugs have encountered disappointing outcomes in terms of improved cognitive performance since they are not capable of halting or stimulating the regeneration of already-damaged neural cells, and merely provide symptomatic relief. Therefore, a deeper understanding of the mechanism of action of stem cell may contribute to the development of novel and effective therapies. The revolutionary discovery of stem cells has cast a new hope for the development of disease-modifying treatments for AD, in terms of their potency in the replenishment of lost cells via differentiating towards specific lineages, stimulating in situ neurogenesis, and delivering the therapeutic agents to the brain. Herein, firstly, we explore the pathophysiology of AD. Next, we summarize the most recent preclinical stem cell reports designed for AD treatment, their benefits and outcomes according to cell type. We briefly review relevant clinical trials and their potential clinical applications in order to find a unique solution to effectively relieve the patients' pain.

Mitochondrial quality control and neurodegenerative diseases

Mitochondria homeostasis is sustained by the mitochondrial quality control (MQC) system, which is crucial for cellular health, especially in the maintenance of functional mitochondria. A healthy mitochondria network is essential for life as it regulates cellular metabolism processes, particularly ATP production. Mitochondrial dynamics and mitophagy are two highly integrated processes in MQC system that determines whether damaged mitochondria will be repaired or degraded. Neurons are highly differentiated cells which demand high energy consumption. Therefore, compromised MQC processes and the accumulation of dysfunctional mitochondria may be the main cause of neuronal death and lead to neurodegeneration. Here, we focus on the inseparable relationship of mitochondria dynamics and mitophagy and how their dysfunction may lead to neurodegenerative diseases.

Update on biomarkers for amyloid pathology in Alzheimer's disease

At the center of Alzheimer's disease pathogenesis is the aberrant aggregation of amyloid-β (Aβ) into oligomers, fibrils and plaques. Effective monitoring of Aβ deposition directly in patients is essential to assist anti-Aβ therapeutics in target engagement and participant selection. In the advent of approved anti-Aβ therapeutics, biomarkers will become of fundamental importance in initiating treatments having disease modifying effects at the earliest stage. Two well-established Aβ biomarkers are widely utilized: Aβ-binding ligands for positron emission tomography and immunoassays to measure Aβ42 in cerebrospinal fluid. In this review, we will discuss the current clinical, diagnostic and research state of biomarkers for Aβ pathology. Furthermore, we will explore the current application of blood-based markers to assess Aβ pathology.

Spore powder of Ganoderma lucidum for the treatment of Alzheimer disease: A pilot study

BACKGROUND

This study explored the feasible efficacy and safety of the Spore Powder of Ganoderma Lucidum (SPGL) for treating patients with Alzheimer disease (AD).

METHODS

Forty-two eligible patients with AD were recruited. These patients were randomly allocated to an intervention group and a control group equally. The patients in the intervention group underwent SPGL, whereas the subjects in the control received placebo. All patients were treated for a total of 6 weeks. The primary outcome was measured by Alzheimer's disease Assessment Scale-Cognitive (ADAS-cog). The secondary outcomes were measured by the World Health Organization Quality of Life questionnaire (WHOQOL-BREF) and Neuropsychiatric Index (NPI). The adverse events were also recorded during the treatment period.

RESULTS

At the end of the treatment, GLSP did not show more encouraging outcomes in symptoms improvement, measured by the ADAS-cog (P = .31), and NPI (P = .79); and quality of life enhancement, measured by the WHOQOL-BREF (physical, P = .62; psychological, P = .69; social relationships, P = .75; environment, P = .82; overall quality of life, P = .74), compared with the control group. In addition, all adverse events were mild, and no significant differences were found between 2 groups.

CONCLUSION

The results of this study did not find the promising efficacy of SPGL for the treatment of AD after 6-week treatment. It may be because of the relative short-term of intervention. Future clinical trials with larger sample size and longer treatment period are urgently needed.

Acupuncture for patients with mild to moderate Alzheimer's disease: a randomized controlled trial

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia. However, none of medical treatment can stop or reverse the underlying neurodegenerative of AD at present. Acupuncture has attracted more and more attention in recent years due to its efficacy and very few side effects. Lately, a systematic review has thought that the evidence on the effectiveness of acupuncture in improving the cognitive function of AD patients was not powerful enough. Therefore, the aim of this study is to explore the efficacy and safety of acupuncture in patients with mild to moderate AD.

METHODS

This was a randomized, controlled, parallel-group, exploratory study with 4-week baseline (T0), 12-week treatment phase (T1) and 12-week follow-up period (T2). Patients with mild to moderate AD meeting the included criteria were randomly allocated into either acupuncture or donepezil hydrochloride groups. The acupuncture group(AG) was given acupuncture treatment three times per week and the donepezil hydrochloride group(DG) group was administered donepezil hydrochloride once daily (5 mg/day for the first 4 weeks and 10 mg/day thereafter). Primary efficacy was measured using Alzheimer's disease Assessment Scale-Cognitive (ADAS-cog) and Clinician's Interview-Based Impression of Change-Plus (CIBIC-Plus). The second outcomes were measured with 23-Item Alzheimer's disease Cooperative Study Activities of Daily Living Scales (ADAS-ADL₂₃) and Neuropsychiatric Index (NPI).

RESULTS

Of 87 participants enrolled in the study, 79 patients finished their treatment and follow-up processes. The ADAS-cog scores for AG group showed obvious decreases at T2 and ∆(T2-T0)when compared with DG group, and significant between-group differences were detected (all p < 0.05). The mean CIBIC-Plus values for the AG group at T1 and T2 were much lower than that for the DG group, and there were significant differences between the two groups (푃<0.05). There were no significant between-group differences in the scores of ADAS-ADL₂₃ and NPI during the study period. Treatment discontinuations due to adverse events were 0 (0%) and 4 (9.09%) for the AG and DG groups, respectively.

CONCLUSIONS

Acupuncture is safe, well tolerated and effective in improving the cognitive function, global clinical status of AD.

TRIAL REGISTRATION

ChiCTR-IOR-17010465 (Retroactively registered on 18 JAN 2017).

Amyloid-Beta-Related Angiitis with Distinctive Neuro-Ophthalmologic Features

Amyloid beta-related angiitis (ABRA) is a subtype of cerebral amyloid angiopathy-related inflammation, with distinctive pathology and prognosis compared with cerebral amyloid angiopathy (CAA). On a spectrum of increasing severity, ABRA is considered to be in-between the less aggressive inflammatory-CAA and the more severe primary central nervous system (CNS) angiitis. Whereas retinal pathological changes were described in subjects with primary or secondary CNS angiitis, and non-inflammatory CAA, bilateral posterior pole superficial and peripapillary retinal hemorrhages have not been reported as initial signs in patients with pathology-confirmed ABRA, accompanying neurological spells and characteristic neuroimaging findings.

A vaccine with Aβ oligomer-specific mimotope attenuates cognitive deficits and brain pathologies in transgenic mice with Alzheimer's disease

Background

β-Amyloid peptide (Aβ) oligomers are initial factors used to induce Alzheimer’s disease (AD) development, and Aβ monomers have normal physiological function. The antibodies or vaccines against Aβ monomers have serious problems, such as side effects and low curative effects. Therefore, it is essential to specifically target Aβ oligomers rather than monomers for the treatment of AD.

Methods

The mimotopes of Aβ oligomers were obtained by panning the phage-displayed random peptide libraries using oligomer-specific antibodies as targets and expressed on the surface of EBY100 Saccharomyces cerevisiae to generate yeast cell base vaccines. One vaccine (AOE1) induced antibodies specifically against Aβ oligomers and was selected for further study. The APP/PS1 mice were subcutaneously immunized with AOE1 eight times. The levels and characteristics of antibodies induced by AOE1 were determined by enzyme-linked immunosorbent assay. The effect of AOE1 on the cognitive deficits of AD mice was tested by novel object recognition (NOR) and Y-maze. Dot blot analysis, Western blot analysis, and immunohistochemistry were applied to measure the effects of AOE1 on Aβ pathologies, neuroinflammation, and microhemorrhages in the brains of AD mice.

Results

Eight mimotope candidates of Aβ oligomers were selected and expressed on EBY100 S. cerevisiae. Only AOE1 vaccine containing mimotope L2 induced antibodies that specifically recognized Aβ42 oligomers rather than monomers. AOE1 immunization significantly increased the AD mice’s exploration times for the novel object in the NOR test and the choices for new arms in the Y-maze test, and it reduced levels of Aβ oligomers and glial activation in the AD mouse brains. No activation of Aβ-specific T cells and microhemorrhages was observed in their brains following AOE1 vaccination.

Conclusions

AOE1 is the first vaccine applying the oligomer-specific mimotope as an immunogen, which could induce antibodies with high specificity to Aβ oligomers. AOE1 immunization attenuated Aβ pathologies and cognitive deficits in AD mice, decreased the overactivation of glial cells, and did not induce microhemorrhage in the brains of AD mice. These findings suggest that AOE1 may be a safer and more effective vaccine for AD treatment.

Development of Immunoassays for the Quantitative Assessment of Amyloid-β in the Presence of Therapeutic Antibody: Application to Pre-Clinical Studies

Utilizing decision making biomarkers in drug development requires thorough assay validation. Special considerations need to be taken into account when monitoring biomarkers using immunoassays in the presence of therapeutic antibodies. We have developed robust and sensitive assays to assess target engagement and proof of mechanism to support the clinical progression of a human monoclonal antibody against the neurotoxic amyloid-β (Aβ)₄₂ peptide. Here we present the introduction of novel pre-treatment steps to ensure drug-tolerant immunoassays and describe the validation of the complete experimental procedures to measure total Aβ₄₂ concentration (bound and unbound) in cerebrospinal fluid (CSF) and plasma, free Aβ₄₂ concentration (unbound) in CSF, and Aβ₄₀ concentration in CSF. The difference in composition of the matrices (CSF and plasma) and antigen levels therein, in combination with the hydrophobic properties of Aβ protein, adds to the complexity of validation. Monitoring pharmacodynamics of an Aβ₄₂ specific monoclonal antibody in a non-human primate toxicology study using these assays, we demonstrated a 1500-fold and a 3000-fold increase in total Aβ₄₂ in plasma, a 4-fold and 8-fold increase in total Aβ₄₂ in CSF together with a 95% and 96% reduction of free Aβ₄₂ in CSF following weekly intravenous injections of 10 mg/kg and 100 mg/kg, respectively. Levels of Aβ₄₀ were unchanged. The accuracy of these data is supported by previous pre-clinical studies as well as predictive pharmacokinetic/pharmacodynamics modeling. In contrast, when analyzing the same non-human primate samples excluding the pre-treatment steps, we were not able to distinguish between free and total Aβ₄₂. Our data clearly demonstrate the importance of thorough evaluation of antibody interference and appropriate validation to monitor different types of biomarkers in the presence of a therapeutic antibody.

Gene-based vaccines and immunotherapeutic strategies against neurodegenerative diseases: Potential utility and limitations

There has been a recent expansion of vaccination and immunotherapeutic strategies from controlling infectious diseases to the targeting of non-infectious conditions including neurodegenerative disorders. In addition to conventional vaccine and immunotherapeutic modalities, gene-based methods that express antigens for presentation to the immune system by either live viral vectors or non-viral naked DNA plasmids have been developed and evaluated. This mini-review/commentary summarizes the advantages and disadvantages, as well as the research findings to date, of both of these gene-based vaccination approaches in terms of how they can be targeted against appropriate antigens within the Alzheimer and Parkinson disease pathogenesis processes as well as potentially against targets in other neurodegenerative diseases. Most recently, the novel utilization of these viral vector and naked DNA gene-based technologies includes the delivery of immunoglobulin genes from established biologically active monoclonal antibodies. This modified passive immunotherapeutic strategy has recently been applied to deliver passive antibody immunotherapy against the pathologically relevant amyloid β protein in Alzheimer disease. The advantages and disadvantages of this technological application of gene-based immune interventions, as well as research findings to date are also summarized. In sum, it is suggested that further evaluation of gene based vaccines and immunotherapies against neurodegenerative diseases are warranted to determine their potential clinical utility.

Current Research Therapeutic Strategies for Alzheimer's Disease Treatment

Alzheimer's disease (AD) currently presents one of the biggest healthcare issues in the developed countries. There is no effective treatment capable of slowing down disease progression. In recent years the main focus of research on novel pharmacotherapies was based on the amyloidogenic hypothesis of AD, which posits that the beta amyloid (Aβ) peptide is chiefly responsible for cognitive impairment and neuronal death. The goal of such treatments is (a) to reduce Aβ production through the inhibition of β and γ secretase enzymes and (b) to promote dissolution of existing cerebral Aβ plaques. However, this approach has proven to be only modestly effective. Recent studies suggest an alternative strategy centred on the inhibition of the downstream Aβ signalling, particularly at the synapse. Aβ oligomers may cause aberrant N-methyl-D-aspartate receptor (NMDAR) activation postsynaptically by forming complexes with the cell-surface prion protein (PrPC). PrPC is enriched at the neuronal postsynaptic density, where it interacts with Fyn tyrosine kinase. Fyn activation occurs when Aβ is bound to PrPC-Fyn complex. Fyn causes tyrosine phosphorylation of the NR2B subunit of metabotropic glutamate receptor 5 (mGluR5). Fyn kinase blockers masitinib and saracatinib have proven to be efficacious in treating AD symptoms in experimental mouse models of the disease.