Clinical aspects of Alzheimer's disease

Role of Impaired Mitochondrial Dynamics Processes in the Pathogenesis of Alzheimer’s Disease

Mitochondrial dysfunction is now recognized as a contributing factor to neurodegenerative diseases, including Alzheimer’s disease (AD). Mitochondria are signaling organelles with a variety of functions ranging from energy production to the regulation of cellular metabolism, energy homeostasis, and response to stress. The successful functioning of these complex processes is critically dependent on the accuracy of mitochondrial dynamics, which includes the ability of mitochondria to change shape and position in the cell, which is necessary to maintain proper function and quality control, especially in polarized cells such as neurons. There has been much evidence to suggest that the disruption of mitochondrial dynamics may play a critical role in the pathogenesis of AD. This review highlights aspects of altered mitochondrial dynamics in AD that may contribute to the etiology of this debilitating condition. We also discuss therapeutic strategies to improve mitochondrial dynamics and function that may provide an alternative treatment approach.

Foresee novel targets for Alzheimer's disease by investigating repurposed drugs

BACKGROUND

Alzheimer's Disease (AD) is the most rampant neurodegenerative disorder which has caused havoc worldwide. More than a century has passed since the first case of AD was reported, but still no stable treatment is known to mankind. The available medications only provide temporary relief and are not a cure for the disease. The hunt for advanced techniques in drug development has paved the way for drug repurposing, i.e., repositioning or reutilizing drugs as an innovative approach.

METHODOLOGY

Several drugs which were repurposed for AD were collected by following PRISMA 2020 systemic review. Databases like PubMed, ScienceDirect, JSTOR, and SciELO were used for data extraction. Further, Drugbank database was used to download all the identified drugs. Later, the Swiss Target Prediction tool was used to identify protein receptors for these drugs and the biological pathway followed by them.

RESULTS

Drugs like Zileuton, Salbutamol, Baricitinib, Carmustine, Paclitaxel, and Nilotinib were observed to be involved in regulation of neurotransmitters. Similarly, Metformin, Liraglutide, UDCA, and Bexarotene are involved in protein kinase cascades which also is one of the prime processes in metabolic disorders like AD. Furthermore, drugs like Rosiglitazone, Pioglitazone, and Lonafarnib are involved in interleukin-3 biosynthetic processes, which is again one of the most important processes studied in AD treatment.

CONCLUSION

The study concluded that the reviewed drugs that follow similar biological and molecular processes can be repurposed for AD if chosen judiciously with current medications and thus drug repurposing is a promising approach that can be utilized to find a cure for AD within a brief time and fewer resources compared to de novo drug synthesis. Although certain loopholes still need to be worked upon, the technique has great prospects. Furthermore, in silico methods can be utilized to justify the findings and identify the best drug candidate.

Gao-Zi-Yao improves learning and memory function in old spontaneous hypertensive rats

Aims

Gao-Zi-Yao has long been a unique way for treating various diseases. The present study is to explore the effect of Gao-Zi-Yao on learning and memory function in old spontaneous hypertensive rats (SHR) and its possible mechanism.

Method

Male old SHR were received different doses of Gao-Zi-Yao for 4 weeks. Systolic blood pressure (SBP) and heart rate were monitored. Serum levels of nitric oxide (NO), interleukin (IL)-1β, IL-2, and tumor necrotic factor (TNF)-α were measured. Morris water maze was performed to test the learning and memory function of the rats. Number of neurons in hippocampus was counted by Nissl staining. Western blot was applied to detect the expressions of learning and memory function related proteins, N-methyl-d-aspartate receptor 2B (NMDAR 2B), glutamate receptor 1 (GluR1), phosphorylated-calmodulin-dependent protein kinase II (p-CaMK II), and phosphorylated-cAMP responsive element-binding protein (p-CREB) in rat hippocampus.

Results

Data showed that Gao-Zi-Yao reduced SBP in old SHR, elevated NO level, and suppressed levels of IL-1β, IL-2, TNF-α. The results of Morris water maze experiment showed that Gao-Zi-Yao dose-dependently improved learning and memory function. Number of neurons in the hippocampal dentate gyrus (DG) region of the old SHR was increased by Gao-Zi-Yao treatment. In addition, Gao-Zi-Yao elevated the protein expressions of NMDAR 2B, GluR1, p-CaMK II, and p-CREB in hippocampus.

Conclusion

Gao-Zi-Yao decreases SBP and improves the learning and memory function of the old SHR by regulation of oxidative stress, inflammatory factors and neuron number in hippocampal DG area and the expression of learning and memory function related proteins.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03630-0.

Cognitive Stimulation in Moderate Alzheimer's Disease

Cognitive stimulation is one of the non-pharmacological therapies recommended for dementia intervention. The present study evaluated the efficacy of an intervention based on cognitive stimulation in people with moderate Alzheimer's disease. Fifty-nine subjects with moderate dementia were randomly assigned to the stimulation group (N = 36) and the control group (N = 35). The treatment group received 16 intervention sessions cognitive tasks. All participants were evaluated with a battery of neuropsychological tests at three time points (pre, post, and follow-up). The treatment group showed significant increases in the three domains studied (memory, attention, and executive functions), although some of these effects were not maintained at follow-up. The control group progressively worsened. Cognitive stimulation was found to be an effective intervention for people with moderate Alzheimer's disease because it helped to maintain memory function, executive functions, and attention. However, the effects were minimized at the 3-month follow-up.

E. Gaafar P, Mousa MR, Fayez AM, Elsheikh MA. Novel Luteolin-Loaded Chitosan Decorated Nanoparticles for Brain-Targeting Delivery in a Sporadic Alzheimer's Disease Mouse Model: Focus on Antioxidant, Anti-Inflammatory, and Amyloidogenic Pathways

Preparation and evaluation of a non-invasive intranasal luteolin delivery for the management of cognitive dysfunction in Alzheimer's disease (AD) using novel chitosan decorated nanoparticles. Development of luteolin-loaded chitosomes was followed by full in vitro characterization. In vivo efficacy was evaluated using a sporadic Alzheimer's disease (SAD) animal model via intracerebroventricular injection of 3 mg/kg streptozotocin (ICV-STZ). Treatment groups of luteolin suspension and chitosomes (50 mg/kg) were then intranasally administered after 5 h of ICV-STZ followed by everyday administration for 21 consecutive days. Behavioral, histological, immunohistochemical, and biochemical studies were conducted. Chitosomes yielded promising quality attributes in terms of particle size (PS) (412.8 ± 3.28 nm), polydispersity index (PDI) (0.378 ± 0.07), Zeta potential (ZP) (37.4 ± 2.13 mv), and percentage entrapment efficiency (EE%) (86.6 ± 2.05%). Behavioral findings showed obvious improvement in the acquisition of short-term and long-term spatial memory. Furthermore, histological evaluation revealed an increased neuronal survival rate with a reduction in the number of amyloid plaques. Biochemical results showed improved antioxidant effects and reduced pro-inflammatory mediators' levels. In addition, a suppression by half was observed in the levels of both Aβ aggregation and hyperphosphorylated-tau protein in comparison to the model control group which in turn confirmed the capability of luteolin-loaded chitosomes (LUT-CHS) in attenuating the pathological changes of AD. The prepared nanoparticles are considered a promising safe, effective, and non-invasive nanodelivery system that improves cognitive function in SAD albino mice as opposed to luteolin suspension.

Methylated ccfDNA from plasma biomarkers of Alzheimer's disease using targeted bisulfite sequencing

Aim: Noninvasive biomarkers such as methylated ccfDNA from plasma could help to support the diagnosis of Alzheimer's disease (AD). Methods: A targeted sequencing protocol was developed to identify candidate biomarkers of AD in methylated ccfDNA extracted from plasma. Results: The authors identified differentially methylated CpGs, regions of which were the same as those identified in previous AD studies. Specifically, a differentially methylated CpG of the LHX2 gene previously identified in a plasma study of AD was replicated in the study. The MBP and DUSP22 regions have been identified in other brain studies of AD and in the authors' study. Conclusion: Although these biomarkers must be validated in other cohorts, methylated ccfDNA could be a relevant noninvasive biomarker in AD.

Alzheimer's Disease-Related Dysbiosis Might Be Triggered by Certain Classes of Antibiotics with Time-Lapse: New Insights into the Pathogenesis?

BACKGROUND

Several putative factors are identified in the literature as causative agents or risk factors for the development of Alzheimer's disease (AD). The amyloid cascade hypothesis has been the main hypothesis about the pathophysiology of AD for decades, but recent studies raised the possible role of dysbiosis in the development of AD, which prevents memory loss.

OBJECTIVE

Finding possible associations between antibiotic consumption patterns and the prevalence of AD in European countries.

METHODS

Antibiotic consumption (European Centre for Disease Prevention and Control, ECDC) for 1997-2007, 2008-2018, and as the whole 1997-2018 period, has been compared to the AD prevalence for 2018 expressed in percentage of the population and statistically analyzed by Pearson calculation.

RESULTS

A significant positive correlation has been found between the AD prevalence (2018) and the average quinolone consumption for the years 1997-2007 (r: 0.37, p: 0.044). A similar association was not observed for the entire 22 years (1997-2018) of the average quinolone consumption, and the years 2008-2018, indicating 10-20 years of time-lapse between the antibiotic exposure and the development of AD. The ratio of broad-spectrum and narrow-spectrum antibiotics (B/N) estimated in the ECDC database for the years of 2008-2018 showed a strong positive association with AD prevalence (2018) (r: 0.406, p: 0.026) and a positive correlation tendency for the entire 22 years 1997-2018 (r: 0.344, p: 0.063), but none for the years 1997-2007 (r: 0.256, p: 0.241).

CONCLUSION

Our study indicated the possible sequential role of certain classes of antibiotics in the development of dysbiosis leading to amyloid deposits of AD, which strengthen the possible role of different mediator molecules (short-chain fatty acids, lipopolysaccharides, etc.) produced by the altered microbiome in the development of AD.

Recent Advances in Understanding of Alzheimer's Disease Progression through Mass Spectrometry-Based Metabolomics

Alzheimer's disease (AD) is the leading cause of dementia in the aging population, but despite extensive research, there is no consensus on the biological cause of AD. While AD research is dominated by protein/peptide-centric research based on the amyloid hypothesis, a theory that designates dysfunction in beta-amyloid production, accumulation, or disposal as the primary cause of AD, many studies focus on metabolomics as a means of understanding the biological processes behind AD progression. In this review, we discuss mass spectrometry (MS)-based AD metabolomics studies, including sample type and preparation, mass spectrometry specifications, and data analysis, as well as biological insights gleaned from these studies, with the hope of informing future AD metabolomic studies.

Targeting Systemic Innate Immune Cells as a Therapeutic Avenue for Alzheimer Disease

Alzheimer disease (AD) is the first progressive neurodegenerative disease worldwide, and the disease is characterized by an accumulation of amyloid in the brain and neurovasculature that triggers cognitive decline and neuroinflammation. The innate immune system has a preponderant role in AD. The last decade, scientists focused their efforts on therapies aiming to modulate innate immunity. The latter is of great interest, since they participate to the inflammation and phagocytose the amyloid in the brain and blood vessels. We and others have developed pharmacological approaches to stimulate these cells using various ligands. These include toll-like receptor 4, macrophage colony stimulating factor, and more recently nucleotide-binding oligomerization domain-containing 2 receptors. This review will discuss the great potential to take advantage of the innate immune system to fight naturally against amyloid β accumulation and prevent its detrimental consequence on brain functions and its vascular system. SIGNIFICANCE STATEMENT: The focus on amyloid β removal from the perivascular space rather than targeting CNS plaque formation and clearance represents a new direction with a great potential. Small molecules able to act at the level of peripheral immunity would constitute a novel approach for tackling aberrant central nervous system biology, one of which we believe would have the potential of generating a lot of interest.

Moringa oleifera: A Tree of Life as a Promising Medicinal Plant for Neurodegenerative Diseases

Moringa oleifera, popularly known as a miracle tree or tree of life, has been extensively used as a functional food and nutritional asset worldwide. Ethnomedicinal and traditional uses of M. oleifera indicate that this plant might have a pleiotropic therapeutic efficacy against most human ailments. In fact, M. oleifera is reported to have several pharmacological activities, including antioxidant, antibacterial, antifungal, antidiabetic, antipyretic, antiulcer, antispasmodic, antihypertensive, antitumor, hepatoprotective, and cardiac stimulant properties. Recently, a few experimental studies reported the neuroprotective effects of M. oleifera against Alzheimer's disease, dementia, Parkinson's disease, stroke, and neurotoxicity-related symptoms. In addition, several neuroprotective phytochemicals have been isolated from M. oleifera, which signifies that it can have promising neuroprotective effects. Therefore, this review aimed to explore the current updates and future prospective of neuroprotective efficacies of M. oleifera.

Design and evaluation of a dashboard to support the comprehension of the progression of patients with dementia in day centers

BACKGROUND AND OBJECTIVE

In day centers, people with dementia are assigned to specific groups to receive care according to the progression of the disease. This article presents the design and evaluation of a dashboard aimed at facilitating the comprehension of the progression of people with dementia to support decision-making of healthcare professionals (HCPs) when determining patient-group assignment.

MATERIALS AND METHOD

A participatory design methodology was followed to build the dashboard. The grounded theory methodology was utilized to identify requirements. A total of 8 HCPs participated in the design and evaluation of a low-fidelity prototype. The perceived usefulness and perceived ease of use of the high-fidelity prototype was evaluated by 15 HCPs (from several day centers) and 38 psychology students utilizing a questionnaire based on the technology acceptance model.

RESULTS

HCPs perceived the dashboard as extremely likely to be useful (Mdn=6.5 out of 7) and quite likely to be usable (Mdn=6 out of 7). Psychology students perceived the dashboard as quite likely to be useful and usable (both with Mdn=6).

CONCLUSIONS

Making use of a participatory design helped foster in HCPs a sense of ownership of the dashboard, thus facilitating its acceptance. The creation of low-fidelity and high-fidelity prototypes led to identifying valuable, timely, and specific feedback at different stages of the development process as well as to establishing a set of lessons learned for the development of dashboards in the healthcare domain.

Analysis of behavioral management for dental treatment in patients with dementia using the Korean National Health Insurance data

Background

The global population is aging rapidly, and accordingly, the number of patients with dementia is increasing every year. Although the need for dental treatment increases for various reasons in patients with dementia, they cannot cooperate during dental treatment. Therefore, behavioral management, including sedation (SED) or general anesthesia (GA), is required for patients with dementia. Thus, this study aimed to investigate the trends and effects of SED or GA in patients with dementia undergoing dental treatment in South Korea based on the Korean National Health Insurance claims data.

Methods

This study utilized customized health information data provided by the Health Insurance Review and Assessment Service. Among patients with records of using sedative drugs during dental treatment from January 2007 to September 2019, patients with the International Classification of Diseases-10 code for dementia (F00, F01, F02, F03, and G30) were selected. We then analyzed the full insurance claims data for dental care. Age, sex, sedative use, and dental treatment of patients were analyzed yearly. In addition, the number of cases of GA or SED per year was analyzed, and changes in behavioral management methods with increasing age were investigated.

Results

Between January 2007 and September 2019, a total of 4,383 (male, 1,454; female, 2,929) patients with dementia received dental treatment under SED or GA. The total number of SED and GA cases were 1,515 (male, 528 ; female, 987) and 3,396 (male, 1,119 ; female, 2,277) cases, respectively. The total number of cases of dental treatment for 4,383 patients with dementia was 153,051 cases, of which 2.22% were under GA and 0.98% were under SED. Midazolam was the most commonly used drug for SED.

Conclusion

Although gingivitis and pulpitis were the most common reasons for patients with dementia to visit the dentist, GA or SED for patients with dementia was frequently used in oral and maxillofacial or periodontal surgery.

Influential role of 7-Ketocholesterol in the progression of Alzheimer's disease

Millions of people are affected by neurodegenerative diseases worldwide. They occur due to the loss of brain functions or peripheral nervous system dysfunction. If untreated, prolonged condition ultimately leads to death. Mostly they are associated with stress, altered cholesterol metabolism, inflammation and organelle dysfunction. Endogenous cholesterol and phospholipids in brain undergo auto-oxidation by enzymatic as well as non-enzymatic modes leading to the formation of by-products such as 4-hydroxynonenal and oxysterols. Among various oxysterols, 7-ketocholesterol (7KCh) is one of the major toxic components involved in altering neuronal lipid metabolism, contributing to inflammation and nerve cell damage. More evidently 7KCh is proven to induce oxidative stress and affects membrane permeability. Loss in mitochondrial membrane potential affects metabolism of cell organelles such as lysosomes and peroxisomes which are involved in lipid and protein homeostasis. This in turn could affect amyloidogenesis, tau protein phosphorylation and accumulation in pathological conditions of neurodegenerative diseases. Lipid alterations and the consequent pathogenic protein accumulation, results in the damage of cell organelles and microglial cells. This could be a reason behind disease progression and predominantly reported characteristics of neurodegenerative disorders such as Alzheimer's disease. This review focuses on the role of 7KCh mediated neurodegenerative Alzheimer's disease with emphasis on alterations in the lipid raft microdomain. In addition, current trends in the significant therapies related to 7KCh inhibition are highlighted.

The Beneficial Role of Natural Endocrine Disruptors: Phytoestrogens in Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia with a growing incidence rate primarily among the elderly. It is a neurodegenerative, progressive disorder leading to significant cognitive loss. Despite numerous pieces of research, no cure for halting the disease has been discovered yet. Phytoestrogens are nonestradiol compounds classified as one of the endocrine-disrupting chemicals (EDCs), meaning that they can potentially disrupt hormonal balance and result in developmental and reproductive abnormalities. Importantly, phytoestrogens are structurally, chemically, and functionally akin to estrogens, which undoubtedly has the potential to be detrimental to the organism. What is intriguing, although classified as EDCs, phytoestrogens seem to have a beneficial influence on Alzheimer's disease symptoms and neuropathologies. They have been observed to act as antioxidants, improve visual-spatial memory, lower amyloid-beta production, and increase the growth, survival, and plasticity of brain cells. This review article is aimed at contributing to the collective understanding of the role of phytoestrogens in the prevention and treatment of Alzheimer's disease. Importantly, it underlines the fact that despite being EDCs, phytoestrogens and their use can be beneficial in the prevention of Alzheimer's disease.

The cognitive dysfunction related to Alzheimer disease or cerebral small vessel disease: What's the differences

ABSTRACT

Alzheimer disease (AD) and sporadic cerebral small vessel disease (CSVD) are common cognitive disorders. Both AD and CSVD have mental symptoms including chronic progressive cognitive impairment, dysfunction, and behavioral abnormalities. However, the differences on the cognitive dysfunction of AD and CSVD remain unclear. It is necessary to elucidate the cognitive dysfunction differences of AD and CSVD, and to identify the potential risk factors.AD or sporadic CSVD patients treated in our hospital from December 1, 2018 to May 31, 2019 were included. And we selected healthy participants as controls. The mini-mental state examination and Montreal Cognitive Assessment Scale were used for neuropsychological assessment, and related medical information were collected and compared.A total of 190 patients were included. The total mini-mental state examination scores in AD, CSVD group were significantly less than that of control group, there were significant differences in the domains of directional ability, attention and computing ability, delayed recall, and visual perception (all P < .05); the total Montreal Cognitive Assessment Scale scores in AD, CSVD group were significantly less than that of control group. There were significant differences in the domains of visual space and execution, immediate remember, attention and computing ability, language, delayed recall, and directional ability (all P < .05); diabetes was a risk factor both for AD (hazard ratio = 1.63, 95% confidence interval: 1.35-1.97) and CSVD (hazard ratio = 1.15, 95% confidence interval: 1.08-1.27).The cognitive dysfunctions of AD are difference to that of CSVD patients, and diabetes is the risk factor both for AD and CSVD, future studies are needed to further identify the prevention and treatment of AD and CSVD.

Evolving Role of Natural Products from Traditional Medicinal Herbs in the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease that causes dementia by impairing mental capacity growth and disrupting neurocognitive activity. Despite recent advancements in AD therapy, therapeutic effectiveness has been small, noncurative, and susceptible to drug resistance. The reality that AD's origin remains unknown and that the blood-brain barrier limits treatment effectiveness are two significant impediments to science. Plants are repositories for novel chemical entities, which provide an exciting avenue for Alzheimer's disease studies. Although several herbal remedies are unquestionably efficient, only a small number have been clinically tested for their active chemical constituents and biological activities. Using published data in the literature, we summarized commonly used medicinal plants and herbs and their phyto components for the care and diagnosis of Alzheimer's disease as an alternative therapy. In this, we summarize the main compounds found in 30 different herbal medicines that target neurodegenerative diseases. Using the experimental study of physicochemical properties, we put forward a hypothesis about potential medicinal plants and the management of Alzheimer's disease. The summary analysis demonstrates that conventional herbal medicines produce compounds with physicochemical properties with a high degree of similarities with existing approved medicines.

Signal and Texture Features from T2 Maps for the Prediction of Mild Cognitive Impairment to Alzheimer's Disease Progression

Early detection of Alzheimer's disease (AD) is crucial to preserve cognitive functions and provide the opportunity for patients to enter clinical trials. In recent years, some studies have reported that features related to the signal and texture of MRI images can be an effective biomarker of AD. To test these claims, a study was conducted using T2 maps, a sequence not previously studied, of 40 patients with mild cognitive impairment (MCI) from the Alzheimer's Disease Neuroimaging Initiative database, who either progressed to AD (18) or remained stable (22). From these maps, the mean value and absolute difference of 37 signal and texture imaging features for 40 contralateral pairs of regions were measured. We used seven machine learning methods to analyze whether, by adding these imaging features to the neuropsychological studies currently used for diagnosis, we could more accurately identify patients who will progress to AD. The predictive models improved with the addition of signal and texture features. Additionally, features related to the signal and texture of the images were much more relevant than volumetric ones. Our results suggest that contralateral signal and texture features should be further investigated as potential biomarkers for the prediction of AD.

Optimized Taste-Masked Microparticles for Orally Disintegrating Tablets as a Promising Dosage Form for Alzheimer's Disease Patients

The objective of this research was to optimize the tasted-masked microparticles for orally disintegrating tablets containing donepezil hydrochloride using quality risk assessment and design of experiment approaches. The double emulsion solvent evaporation technique using aminoalkyl methacrylate copolymer (AMC) was used to prepare taste-masked microparticles. Factors affecting the quality of the taste-masked microparticles were analyzed using an Ishikawa diagram. A risk-ranking approach was used to rank the formulation and process risks. Furthermore, the effect of AMC quantity, stirring time, and volume of outer water phase on various responses, such as particle size, the amount of drug dissolved at 5 min (Q5) in simulated saliva fluid, and mean dissolution time (MDT) in simulated gastric fluid, was investigated using the Box-Behnken design. The optimized microparticles were then used to prepare orally disintegrating tablets (ODTs) and evaluated by in vitro and in vivo testing. The results demonstrated that particle size was influenced by the AMC amount and stirring time. Q5 was significantly affected by the amount of AMC and the volume of the outer water phase. On the other hand, these two factors had a positive effect on MDT. The optimized microparticles had a particle size of 174.45 ± 18.19 µm, Q5 of 5.04%, and MDT of 5.97 min. The ODTs with taste-masked microparticles showed acceptable in vitro dissolution with an MDT of 5 min. According to the results of a panel of six human volunteers, they greatly improved palatability.

β-Amyloid Clustering around ASC Fibrils Boosts Its Toxicity in Microglia

Alzheimer’s disease is the world’s most common neurodegenerative disorder. It is associated with neuroinflammation involving activation of microglia by β-amyloid (Aβ) deposits. Based on previous studies showing apoptosis-associated speck-like protein containing a CARD (ASC) binding and cross-seeding extracellular Aβ, we investigate the propagation of ASC between primary microglia and the effects of ASC-Aβ composites on microglial inflammasomes and function. Indeed, ASC released by a pyroptotic cell can be functionally built into the neighboring microglia NOD-like receptor protein (NLRP3) inflammasome. Compared with protein-only application, exposure to ASC-Aβ composites amplifies the proinflammatory response, resulting in pyroptotic cell death, setting free functional ASC and inducing a feedforward stimulating vicious cycle. Clustering around ASC fibrils also compromises clearance of Aβ by microglia. Together, these data enable a closer look at the turning point from acute to chronic Aβ-related neuroinflammation through formation of ASC-Aβ composites.

Friker et al. investigate the reaction of primary microglia to exogenous ASC and ASC-Aβ composites. They uncover a vicious circle involving amplified NLRP3 inflammasome activity and reduced Aβ clearance in the presence of ASC that might play a key role in Alzheimer’s disease progression.

Molecular mechanisms in Alzheimer's disease and the impact of physical exercise with advancements in therapeutic approaches

Alzheimer's disease (AD) is one of the most common, severe neurodegenerative brain disorder characterized by the accumulation of amyloid-beta plaques, neurofibrillary tangles in the brain causing neural disintegration, synaptic dysfunction, and neuronal death leading to dementia. Although many US-FDA-approved drugs like Donepezil, Rivastigmine, Galantamine are available in the market, their consumption reduces only the symptoms of the disease but fails in potency to cure the disease. This disease affects many individuals with aging. Combating the disease tends to be very expensive. This review focuses on biochemical mechanisms in the neuron both at normal and AD state with relevance to the tau hypothesis, amyloid hypothesis, the risk factors influencing dementia, oxidative stress, and neuroinflammation altogether integrated with neurodegeneration. A brief survey is carried out on available biomarkers in the diagnosis of the disease, drugs used for the treatment, and the challenges in approaching therapeutic targets in inhibiting the disease pathologies. This review conjointly assesses the demerits with the inefficiency of drugs to reach targets, their side effects, and toxicity. Optimistically, this review directs on the advantageous strategies in using nanotechnology-based drug delivery systems to cross the blood-brain barrier for improving the efficacy of drugs combined with a novel neuronal stem cell therapy approach. Determinately, this review aims at the natural, non-therapeutic healing impact of physical exercise on different model organisms and the effect of safe neuromodulation treatments using repetitive Transcranial Magnetic Stimulation (rTMS), transcranial Electrical Stimulation (tES) in humans to control the disease pathologies prominent in enhancing the synaptic function.

Contributors and Moderators of Quality of Life in Caregivers of Alzheimer´s Disease Patients

Aim and objective: This study aimed to identify the variables that contributed to Quality of Life (QoL) of Alzheimer's Disease (AD) caregivers, taking into consideration the caregiving context, stressors, role strains, and resources.Methods: The sample included 102 caregivers of AD patients who answered the following instruments: Depression, Anxiety and Stress Scale-21; Satisfaction with Social Support Scale; Revised Memory and Behavioral Problems Checklist; Family Communication and Satisfaction Scales; Spiritual and Religious Attitudes in Dealing with Illness; and Quality of Life in Alzheimer's Disease - Caregiver Version.Results: Caregivers who were employed, chose the caregiving role, and received help in caring showed better QoL. Also, being younger, less caregiving daily hours, caring for patients with less memory and behavior problems, lower distress, and family satisfaction predicted better QoL. Finally, spirituality was a moderator between family communication and QoL but not between family satisfaction and QoL.Conclusion: Caregiving-context variables (age, professional status, choosing to care, receiving help in the caregiving role and duration of daily care); role strains (family dissatisfaction); stressors (caregivers' distress and patients' memory and behavioral problems); and resources (spirituality) had an impact on caregivers' QoL emphasizing the adequacy of the Stress Process Model. Intervention should also focus on spirituality given its moderating role.

Extract of the Aerial Part of Polygala tenuifolia Attenuates d-Galactose/NaNO2-induced Learning and Memory Impairment in Mice

Alzheimer's disease, one of the most common types of age-related dementia, is characterized by memory deterioration and behavior disorder. The aboveground part of Polygala tenuifolia is a traditional Chinese medicine used for the treatment of amnesia. This study was conducted to investigate the ameliorating effect of the aerial part of P. tenuifolia on d-galactose/NaNO₂-induced learning and memory impairment in mice. d-galactose (120 mg/kg) and NaNO₂ (90 mg/kg) were injected intraperitoneally for 60 days to induce learning and memory impairment in mice. The aerial part of P. tenuifolia (25, 50, and 100 mg/kg) and piracetam (200 mg/kg) were simultaneously administered orally on days 15 - 60. Results of this study showed that aerial part of P. tenuifolia significantly decreased the latency time and increased the number of platform crossings in the Morris water maze compared with the Model group. Moreover, the aerial part of P. tenuifolia significantly increased the latency time and decreased the error frequency in the step-down and step-through tests compared with the Model group. Meanwhile, the aerial part of P. tenuifolia was able to regulate the cholinergic system by increasing the levels of ACh and ChAT and decreasing the level of AChe. The aerial part of P. tenuifolia also significantly attenuated the levels of interleukin-1 beta and malonaldehyde and enhanced the interleukin-10 and glutathione levels and superoxide dismutase activity. Furthermore, treatment with aerial part of P. tenuifolia increased the protein and mRNA expression of brain-derived neurotrophic factor and tropomyosin receptor kinase B in the hippocampus. These results suggest that the aerial part of P. tenuifolia can ameliorate learning and memory impairments by modulating cholinergic activity, inhibiting neuroinflammation and oxidative stress, and regulating the brain-derived neurotrophic factor and tropomyosin receptor kinase B signaling pathway.

Neuroprotective effects of the aerial parts of Polygala tenuifolia Willd extract on scopolamine-induced learning and memory impairments in mice

Alzheimer's disease is a common neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. Aerial parts of Polygala tenuifolia Willd (APT) is a traditional Chinese medicine used for the treatment of amnesia. The present study aimed to investigate the protective effects of APT on scopolamine-induced learning and memory impairments in mice. Scopolamine-induced mice were used to determine the effects of APT on learning and memory impairment. Mice were orally administered with APT (25, 50 and 100 mg/kg) and piracetam (750 mg/kg) for 14 days, and intraperitoneally injected with scopolamine (2 mg/kg) from days 8 to 14. Morris water maze and step-down tests were performed to evaluate learning and memory. Levels of acetylcholine (ACh), choline acetyltransferase (ChAT), acetylcholinesterase (AChE), interleukin (IL)-1β, IL-10 and brain-derived neurotrophic factor (BDNF) in the hippocampus and frontal cortex were measured by ELISA. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were measured via biochemical detection. The results demonstrated that APT ameliorated learning and memory impairment in scopolamine-induced mice. Correspondingly, APT significantly increased ACh and ChAT levels in the hippocampus and prefrontal cortex of scopolamine-induced mice. Additionally, treatment with APT significantly increased BDNF and IL-10 levels, and decreased IL-1β and AChE levels in the same mice. Furthermore, APT significantly increased SOD activity and GSH content, and decreased MDA levels in brain tissue. These results indicated that APT may ameliorate learning and memory impairment by regulating cholinergic activity, promoting BDNF and inhibiting neuroinflammation and oxidative stress.

Astrocytic palmitoylethanolamide pre-exposure exerts neuroprotective effects in astrocyte-neuron co-cultures from a triple transgenic mouse model of Alzheimer's disease

Palmitoylethanolamide (PEA) is an endogenous lipid mediator that, also by blunting astrocyte activation, demonstrated beneficial properties in several in vitro and in vivo models of Alzheimer's disease (AD). In the present study, we used astrocyte-neuron co-cultures from 3xTg-AD mouse (i.e. an animal model of AD) cerebral cortex to further investigate on the role of astrocytes in PEA-induced neuroprotection. To this aim, we evaluated the number of viable cells, apoptotic nuclei, microtubule-associated protein-2 (MAP2) positive cells and morphological parameters in cortical neurons co-cultured with cortical astrocytes pre-exposed, or not, to Aβ₄₂ (0.5 μM; 24 h) or PEA (0.1 μM; 24 h). Pre-exposure of astrocytes to Aβ₄₂ failed to affect the viability, the number of neuronal apoptotic nuclei, MAP2 positive cell number, neuritic aggregations/100 μm, dendritic branches per neuron, the neuron body area, the length of the longest dendrite and number of neurites/neuron in 3xTg-AD mouse astrocyte-neuron co-cultures. Compared to neurons from wild-type (non-Tg) mouse co-cultures, 3xTg-AD mouse neurons co-cultured with astrocytes from this mutant mice displayed higher number of apoptotic nuclei, lower MAP2 immunoreactivity and several morphological changes. These signs of neuronal suffering were significantly counteracted when the 3xTg-AD mouse cortical neurons were co-cultured with 3xTg-AD mouse astrocytes pre-exposed to PEA. The present data suggest that in astrocyte-neuron co-cultures from 3xTg-AD mice, astrocytes contribute to neuronal damage and PEA, by possibly counteracting reactive astrogliosis, improved neuronal survival. These findings further support the role of PEA as a possible new therapeutic opportunity in AD treatment.

Recent Developments in Microfluidic Technologies for Central Nervous System Targeted Studies

Neurodegenerative diseases (NDs) bear a lot of weight in public health. By studying the properties of the blood-brain barrier (BBB) and its fundamental interactions with the central nervous system (CNS), it is possible to improve the understanding of the pathological mechanisms behind these disorders and create new and better strategies to improve bioavailability and therapeutic efficiency, such as nanocarriers. Microfluidics is an intersectional field with many applications. Microfluidic systems can be an invaluable tool to accurately simulate the BBB microenvironment, as well as develop, in a reproducible manner, drug delivery systems with well-defined physicochemical characteristics. This review provides an overview of the most recent advances on microfluidic devices for CNS-targeted studies. Firstly, the importance of the BBB will be addressed, and different experimental BBB models will be briefly discussed. Subsequently, microfluidic-integrated BBB models (BBB/brain-on-a-chip) are introduced and the state of the art reviewed, with special emphasis on their use to study NDs. Additionally, the microfluidic preparation of nanocarriers and other compounds for CNS delivery has been covered. The last section focuses on current challenges and future perspectives of microfluidic experimentation.

Cannabis sativa: Much more beyond Δ9-tetrahydrocannabinol

Cannabis is the most used illicit drug worldwide and its medicinal use is under discussion, being regulated in several countries. However, the psychotropic effects of Δ⁹-tetrahydrocannabinol (THC), the main psychoactive compound of Cannabis sativa, are of concern. Thus, the interest in the isolated constituents without psychotropic activity, such as cannabidiol (CBD) and cannabidivarin (CBDV) is growing. CBD and CBDV are lipophilic molecules with poor oral bioavailability and are mainly metabolized by cytochrome P450 (CYP450) enzymes. The pharmacodynamics of CBD is the best explored, being able to interact with diverse molecular targets, like cannabinoid receptors, G protein-coupled receptor-55, transient receptor potential vanilloid 1 channel and peroxisome proliferator-activated receptor-γ. Considering the therapeutic potential, several clinical trials are underway to study the efficacy of CBD and CBDV in different pathologies, such as neurodegenerative diseases, epilepsy, autism spectrum disorders and pain conditions. The anti-cancer properties of CBD have also been demonstrated by several pre-clinical studies in different types of tumour cells. Although less studied, CBDV, a structural analogue of CBD, is receiving attention in the last years. CBDV exhibits anticonvulsant properties and, currently, clinical trials are underway for the treatment of autism spectrum disorders. Despite the benefits of these phytocannabinoids, it is important to highlight their potential interference with relevant physiologic mechanisms. In fact, CBD interactions with CYP450 enzymes and with drug efflux transporters may have serious consequences when co-administered with other drugs. This review summarizes the therapeutic advances of CBD and CBDV and explores some aspects of their pharmacokinetics, pharmacodynamics and possible interactions. Moreover, it also highlights the therapeutic potential of CBD and CBDV in several medical conditions and clinical applications.

Chronic Oral Palmitoylethanolamide Administration Rescues Cognitive Deficit and Reduces Neuroinflammation, Oxidative Stress, and Glutamate Levels in A Transgenic Murine Model of Alzheimer's Disease

N-palmitoylethanolamide (PEA) is a lipid mediator belonging to the class of the N-acylethanolamine. Products containing PEA, also in ultramicronized formulation (um-PEA), are already licensed for use in humans for its analgesic and anti-inflammatory properties, and demonstrated high safety and tolerability. Preclinical studies indicate that PEA, especially in the ultramicronized form, could be a potential therapeutic agent for Alzheimer's disease (AD). In this study, we evaluated the neuroprotective and antioxidant effects of chronic (three months) um-PEA administration in an animal model of AD (3×Tg-AD mice). For translation purposes, the compound has been orally administered. Cognitive performance as well as biochemical markers [(interleukin-16 (IL-16) and tumor necrosis factor- (TNF-)] levels, reactive oxygen species (ROS) production, synaptophysin and glutamate levels) have been evaluated at the end of um-PEA treatment. The results indicate that orally administered um-PEA was adsorbed and distributed in the mice brain. The chronic treatment with um-PEA (100 mg/kg/day for three months) rescued cognitive deficit, restrained neuroinflammation and oxidative stress, and reduced the increase in hippocampal glutamate levels observed in 3×Tg-AD mice. Overall, these data reinforce the concept that um-PEA exerts beneficial effects in 3×Tg-AD mice. The fact that PEA is already licensed for the use in humans strongly supports its rapid translation in clinical practice.

Collapsin Response Mediator Proteins: Novel Targets for Alzheimer's Disease

Numerous experimental and postmortem studies have increasingly reported dystrophic axons and dendrites, and alterations of dendritic spine morphology and density in the hippocampus as prominent changes in the early stages of Alzheimer's disease (AD). Furthermore, these alterations tend to correlate well with the progressive cognitive decline observed in AD. For these reasons, and because these neurite structures have a capacity to re-grow, re-establish lost connections, and are critical for learning and memory, there is compelling evidence to suggest that therapeutic interventions aimed at preventing their degradation or promoting their regrowth may hold tremendous promise in preventing the progression of AD. In this regard, collapsin response mediator proteins (CRMPs), a family of phosphoproteins playing a major role in axon guidance and dendritic growth, are especially interesting. The roles these proteins play in neurons and immune cells are reviewed here.