Cholinesterase Inhibitors May Not Benefit Mild Cognitive Impairment and Mild Alzheimer Disease Dementia

Exploring Patient Perspectives: A Structured Interview Study on Deep Brain Stimulation as a Novel Treatment Approach for Mild Cognitive Impairment

INTRODUCTION

Limited treatments for Mild Cognitive Impairment (MCI) highlight the need to explore innovations including Deep Brain Stimulation (DBS), with patient perspectives key to ethical protocol development.

METHODS

Seven MCI patients and four care partners were interviewed (Feb 2023-Jan 2024) about daily MCI challenges, desired treatment outcomes, and views on DBS. Thematic analysis following COREQ guidelines identified key themes.

RESULTS

DBS was a novel concept for all (7/7), and most expressed interest (6/7) despite concerns about invasiveness (6/7) and preference to exhaust medications first (4/7). Care partners (4/4) shared concerns about invasiveness and emphasized proven efficacy. Key deciding factors included the involved procedural risk (6/7), desired significant outcomes (6/7), and prior testing for MCI (7/7). Most participants (6/7) were hesitant to be the first to try DBS, while one was willing.

CONCLUSION

Patient and care partner insights on DBS for MCI are crucial for balancing innovation with ethical, patient-centered research.

15 Years of Longitudinal Genetic, Clinical, Cognitive, Imaging, and Biochemical Measures in DIAN

This manuscript describes and summarizes the Dominantly Inherited Alzheimer Network Observational Study (DIAN Obs), highlighting the wealth of longitudinal data, samples, and results from this human cohort study of brain aging and a rare monogenic form of Alzheimer's disease (AD). DIAN Obs is an international collaborative longitudinal study initiated in 2008 with support from the National Institute on Aging (NIA), designed to obtain comprehensive and uniform data on brain biology and function in individuals at risk for autosomal dominant AD (ADAD). ADAD gene mutations in the amyloid protein precursor (APP), presenilin 1 (PSEN1), or presenilin 2 (PSEN2) genes are deterministic causes of ADAD, with virtually full penetrance, and a predictable age at symptomatic onset. Data and specimens collected are derived from full clinical assessments, including neurologic and physical examinations, extensive cognitive batteries, structural and functional neuro-imaging, amyloid and tau pathological measures using positron emission tomography (PET), flurordeoxyglucose (FDG) PET, cerebrospinal fluid and blood collection (plasma, serum, and whole blood), extensive genetic and multi-omic analyses, and brain donation upon death. This comprehensive evaluation of the human nervous system is performed longitudinally in both mutation carriers and family non-carriers, providing one of the deepest and broadest evaluations of the human brain across decades and through AD progression. These extensive data sets and samples are available for researchers to address scientific questions on the human brain, aging, and AD.

Brain Age Is Associated with Cognitive Outcomes of Cholinesterase Inhibitor Treatment in Patients with Mild Cognitive Impairment

Background

The effect of cholinesterase inhibitor (ChEI) on mild cognitive impairment (MCI) is controversial. Brain age has been shown to predict Alzheimer's disease conversion from MCI.

Objective

The study aimed to show that brain age is related to cognitive outcomes of ChEI treatment in MCI.

Methods

Brain MRI, the Clinical Dementia Rating (CDR) and Mini-Mental State Exam (MMSE) scores were retrospectively retrieved from a ChEI treatment database. Patients who presented baseline CDR of 0.5 and received ChEI treatment for at least 2 years were selected. Patients with stationary or improved cognition as verified by the CDR and MMSE were categorized to the ChEI-responsive group, and those with worsened cognition were assigned to the ChEI-unresponsive group. A gray matter brain age model was built with a machine learning algorithm by training T1-weighted MRI data of 362 healthy participants. The model was applied to each patient to compute predicted age difference (PAD), i.e. the difference between brain age and chronological age. The PADs were compared between the two groups.

Results

58 patients were found to fit the ChEI-responsive criteria in the patient data, and 58 matched patients that fit the ChEI-unresponsive criteria were compared. ChEI-unresponsive patients showed significantly larger PAD than ChEI-responsive patients (8.44±8.78 years versus 3.87±9.02 years, p = 0.0067).

Conclusions

Gray matter brain age is associated with cognitive outcomes after 2 years of ChEI treatment in patients with the CDR of 0.5. It might facilitate the clinical trials of novel therapeutics for MCI.

The effects of transcranial direct current stimulation on cognitive function for mild cognitive impairment: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) emerged as a potential modality for enhancing cognitive functions in patients with cognitive decline, including mild cognitive impairment (MCI). Our systematic review and meta-analysis aim to synthesize the available randomized controlled trials (RCTs) on the effects of tDCS on cognitive functions in patients with MCI.

METHODS

Our review protocol was registered on PROSPERO with ID: CRD42022360587. We conducted a systematic database search until September 2022. Standardized mean difference (SMD) and pooled effect size (ES) for robust variance estimation (RVE) method were used as effect estimates for our meta-analysis.

RESULTS

We included 11 RCTs with a total of 429 participants. The meta-analysis showed that, compared to sham groups, tDCS did not improve global functioning (measured by MOCA) (SMD = 0.02, CI =  - 0.30 to 0.35; p = 0.88), memory domain (ES = 0.681, CI =  - 2.15 to 3.51, p = 0.576), sustained attention (measured by TMT-A) (SMD =  - 0.21, CI =  - 0.52 to 0.10, p = 0.19), and executive function (measured by TMT-B) (SMD =  - 0.53, CI =  - 1.56 to 0.50, p = 0.20).

CONCLUSION

Our meta-analysis found no significant effect of tDCS on cognitive functions in MCI patients, including effects on global functioning, memory, sustained attention, and executive function. Therefore, an important change to be tested in future studies is to look for a better combination with tDCS for patients with MCI.

A High-Density Raman Photometry for Tracking and Quantifying of AchE Activity in The Brain of Freely Moving Animals with Network

A high-density Raman photometry based on a dual-recognition strategy is created for accurately quantifying acetylcholinesterase (AchE) activity in 24 brain regions of free-moving animals with network. A series of 5-ethynyl-1,2,3,3-tetramethyl-based molecules with different conjugated structures and substitute groups are designed and synthesized for specific recognition of AchE by Raman spectroscopy. After systematically evaluating the recognition ability toward AchE, 2-(4-((4-(dimethylamino)benzoyl)oxy)styryl)-5-ethynyl-1,3,3-trimethyl-3H-indol-1-ium (ET-5) is finally optimized for AchE determination, which shows the highest selectivity, the greatest sensitivity, and the fastest response time among the investigated seven molecules. More interestingly, using the developed probe for AchE with high accuracy and sensitivity, the optimized AchE regulated by nitric oxide (NO) is discovered for promoting the neurogenesis of neural stem cells (NSCs). Benefiting from the high-density photometry, it is found that the activity and distribution of AchE varied in 24 brain regions, and the levels of AchE activity in 24 brain regions of Alzheimer's mice (AD) are lower than those of normal mice. It is the first time that a functional network of AchE in 24 brain regions is established. It is also found that the loss of AchE functional network in AD mice is restored and reconstructed by the controlled release of AchE regulated by NO.

A randomized, double-blind, placebo-controlled, parallel-group 12-week pilot phase II trial of SaiLuoTong (SLT) for cognitive function in older adults with mild cognitive impairment

INTRODUCTION

This study primarily aimed to evaluate the efficacy and safety of SaiLuoTong (SLT) on cognition in mild cognitive impairment (MCI).

METHODS

Community-dwelling people with MCI aged ≥60 years were randomly assigned to 180 mg/day SLT or placebo for 12 weeks.

RESULTS

Thirty-nine participants were randomized to each group (N = 78); 65 were included in the final analysis. After 12 weeks, the between-groups difference in Logical Memory delayed recall scores was 1.40 (95% confidence interval [CI]: 0.22 to 2.58; P = 0.010); Delis-Kaplan Executive Function System Trail Making Test Condition 4 switching and contrast scaled scores were 1.42 (95% CI: -0.15 to 2.99; P = 0.038) and 1.56 (95% CI: -0.09 to 3.20; P = 0.032), respectively; Rey Auditory Verbal Learning Test delayed recall was 1.37 (95% CI: -0.10 to 2.84; P = 0.034); and Functional Activities Questionnaire was 1.21 (95% CI: -0.21 to 2.63; P = 0.047; P < 0.001 after controlling for baseline scores).

DISCUSSION

SLT is well tolerated and may be useful in supporting aspects of memory retrieval and executive function in people with MCI.

Highlights

SaiLuoTong (SLT) improves delayed memory retrieval and executive function in people with mild cognitive impairment (MCI).SLT is well tolerated in people ≥ 60 years.The sample of community dwellers with MCI was well characterized and homogeneous.

Molecular docking analysis of acetylcholinesterase inhibitors for Alzheimer's disease management

Alzheimer's disease (AD) is a neurological disease that is related to aging and is the leading cause of dementia globally. AD has a significant influence on cognitive functions, particularly memory, resulting in a variety of functional deficits. Given the increasing prevalence of AD, there is an urgent need for the development of effective therapeutic therapies. In a quest to uncover a holistic remedy for AD, a total of 41 bioactive compounds derived from three distinct medicinal plant sources were screened to evaluate their potential to inhibit the active sites of acetylcholinesterase (AChE). The insilico screening protocol included 24 licorice-derived compounds, 5 ginkgo biloba-derived compounds, and 11 ginseng-derived compounds. Two compounds (Ginkgolide A and Licorice glycoside D2) were observed to display greater binding energy (BE) relative to the control by interacting with crucial residues in the active site of AChE. Ginkgolide A and Licorice glycoside D2 exhibited BEs of -11.3 and -11.2 kcal/mol, respectively, whereas the control, Donepezil, demonstrated a BE of -10.8 kcal/mol. Further, these compounds exhibit favorable drug-likeness properties. This study suggests that further experimental investigations can be conducted on Ginkgolide A and Licorice glycoside D2 to explore their potential therapeutic applications for AD.

Probiotic intervention benefits multiple neural behaviors in older adults with mild cognitive impairment

Probiotic supplements were shown to improve cognitive function in Alzheimer's disease (AD) patients. However, it is still unclear whether this applies to older individuals with mild cognitive impairment (MCI). We aimed to explore the effects of probiotic supplementation on multiple neural behaviors in older adults with MCI. Forty-two MCI patients (age > 60 years) were randomly divided into two groups and consumed either probiotics (n=21) or placebo (n=21) for 12 weeks. Various scale scores, gut microbiota measures and serological indicators were recorded pre- and posttreatment. After 12 weeks of intervention, cognitive function and sleep quality were improved in the probiotic group compared with those in the control group, and the underlying mechanisms were associated with changes in the intestinal microbiota. In conclusion, our study demonstrated that probiotic treatment enhanced cognitive function and sleep quality in older MCI patients, thus providing important insights into the clinical prevention and treatment of MCI.

Insulin‐like growth factor‐2 is a promising candidate for the treatment and prevention of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia. Current AD treatments slow the rate of cognitive decline, but do not restore lost function. One reason for the low efficacy of current treatments is that they fail to target neurotrophic processes, which are thought to be essential for functional recovery. Bolstering neurotrophic processes may also be a viable strategy for preventative treatment, since structural losses are thought to underlie cognitive decline in AD. The challenge of identifying presymptomatic patients who might benefit from preventative treatment means that any such treatment must meet a high standard of safety and tolerability. The neurotrophic peptide insulin-like growth factor-2 (IGF2) is a promising candidate for both treating and preventing AD-induced cognitive decline. Brain IGF2 expression declines in AD patients. In rodent models of AD, exogenous IGF2 modulates multiple aspects of AD pathology, resulting in (1) improved cognitive function; (2) stimulation of neurogenesis and synaptogenesis; and, (3) neuroprotection against cholinergic dysfunction and beta amyloid-induced neurotoxicity. Preclinical evidence suggests that IGF2 is likely to be safe and tolerable at therapeutic doses. In the preventative treatment context, the intranasal route of administration is likely to be the preferred method for achieving the therapeutic effect without risking adverse side effects. For patients already experiencing AD dementia, routes of administration that deliver IGF2 directly access the CNS may be necessary. Finally, we discuss several strategies for improving the translational validity of animal models used to study the therapeutic potential of IGF2.

Identifying factors influencing cognitive outcomes after anodal transcranial direct current stimulation in older adults with and without cognitive impairment: A systematic review

Anodal transcranial direct current stimulation (tDCS) can improve cognition in healthy older adults, those with Alzheimer's disease (AD) and mild cognitive impairment (MCI), albeit with considerable variability in response. This systematic review identifies interindividual factors that may influence tDCS outcomes in older individuals with or without cognitive impairment. Peer-reviewed articles were included if they assessed whether cognitive outcomes (memory or global cognition) after tDCS were associated with pre-intervention factors in healthy older adults or individuals with AD/MCI. We identified eight factors that may affect cognitive outcomes after tDCS. Improved tDCS outcomes were predicted by lower baseline cognitive function when tDCS was combined with a co-intervention (but not when used alone). Preserved brain structure and better baseline functional connectivity, genetic polymorphisms, and the use of concomitant medications may predict better tDCS outcomes, but further research is warranted. tDCS outcomes were not consistently associated with age, cognitive reserve, sex, and AD risk factors. Accounting for individual differences in baseline cognition, particularly for combined interventions, may thus maximize the therapeutic potential of tDCS.

Type 2 Diabetes Comorbidity and Cognitive Decline in Patients with Alzheimer's Disease

BACKGROUND

Although insulin dysregulation and resistance likely participate in Alzheimer's disease (AD) etiologies, little is known about the correlation between type 2 diabetes mellitus (T2DM) and the progression of cognitive decline in patients with AD.

OBJECTIVE

To determine whether AD patients with T2DM experience more rapid cognitive decline than those without T2DM.

METHODS

All cognitive performance data and the presence or absence of T2DM comorbidity in patients with AD were derived from the US National Alzheimer's Coordinating Center's (NACC) Uniform Data Set (UDS). A search of the UDS identified 3,055 participants with AD who had more than one epoch completed. The data set culled clinically diagnosed AD dementia patients who were assessed for diabetes type identified during at least 1 visit. These patients were divided into 2 groups based on whether they had a diagnosis of T2DM. The data from these groups were then analyzed for differences in cognitive decline based on neuropsychological test battery scores and a Clinician Dementia Rating using a general linear model.

RESULTS

Comparisons of the mean scores for 16 selected tests from the neuropsychological test battery showed no significant differences in baseline scores and scores at subsequent visits between the T2DM and nondiabetic groups.

CONCLUSIONS

The results revealed no differences in cognitive decline metrics over the course of 5 visits in either study group. These data indicate that the presence of T2DM does not increase the rate of cognitive decline in AD. This finding contradicts expected disease burden and will need to be explored further.

The pharmacokinetics profiles, pharmacological properties, and toxicological risks of dehydroevodiamine: A review

Dehydroevodiamine (DHE) is a quinazoline alkaloid isolated from Evodiae Fructus (EF, Wuzhuyu in Chinese, Rutaceae family), a well-known traditional Chinese medicine (TCM) which is clinically applied to treat headache, abdominal pain, menstrual pain, abdominal distension, vomiting, acid regurgitation, etc. Modern research demonstrates that DHE is one of the main components of EF. In recent years, DHE has received extensive attention due to its various pharmacological activities. This review is the first to comprehensively summarize the current studies on pharmacokinetics profiles, pharmacological properties, and toxicological risks of DHE in diverse diseases. Pharmacokinetic studies have shown that DHE has a relatively good oral absorption effect in the mean concentration curves in rat plasma and high absorption in the gastrointestinal tract. In addition, distribution re-absorption and enterohepatic circulation may lead to multiple blood concentration peaks of DHE in rat plasma. DHE possesses a wide spectrum of pharmacological properties in the central nervous system, cardiovascular system, and digestive system. Moreover, DHE has anti-inflammatory effects via downregulating pro-inflammatory cytokines and inflammatory mediators. Given the favorable pharmacological activity, DHE is expected to be a potential drug candidate for the treatment of Alzheimer's disease, chronic stress, amnesia, chronic atrophic gastritis, gastric ulcers, and rheumatoid arthritis. In addition, toxicity studies have suggested that DHE has proarrhythmic effects and can impair bile acid homeostasis without causing hepatotoxicity. However, further rigorous and well-designed studies are needed to elucidate the pharmacokinetics, pharmacological effects, potential biological mechanisms, and toxicity of DHE.

APOE ε4 Carrier Status as Mediator of Effects of Psychotropic Drugs on Clinical Changes in Patients With Alzheimer's Disease

OBJECTIVE

Neuropsychiatric syndromes have been associated with memory dysfunction and risk of and earlier onset of dementia, but how psychotropic drugs affect clinical changes in Alzheimer's disease is not entirely clear. This study aimed to assess the prospective effects of psychotropic drugs on cognitive and functional changes in Alzheimer's disease according to APOE ε4 carrier status.

METHODS

The study included consecutive outpatients with late-onset Alzheimer's disease (N=193) and examined score variations at 1 year on the following tests: Clinical Dementia Rating sum of boxes, Mini-Mental State Examination, Severe Mini-Mental State Examination (SMMSE), Brazilian version of the Zarit Caregiver Burden Interview, Index of Independence in Activities of Daily Living, and Lawton's Instrumental Activities of Daily Living Scale. Analyses of score variations accounted for the use of psychotropic drugs or the number of different medications in use, as well as APOE ε4 carrier status, with significance at p<0.05.

RESULTS

For APOE ε4 noncarriers (N=90), cholinesterase inhibitors were beneficial regarding caregiver burden (p=0.030) and basic functionality (p=0.046), memantine was harmful regarding SMMSE score changes (p=0.032), second-generation antipsychotics had nonsignificant harmful effects on SMMSE score changes (p=0.070), and antiepileptic therapy (p=0.001) and the number of different medications in use (p=0.006) were harmful in terms of basic functionality. APOE ε4 carriers (N=103) did not experience any effects of isolated psychotropic drugs on clinical changes, including antidepressants.

CONCLUSIONS

Results support the harmful prospective effects of second-generation antipsychotics and antiepileptic drugs on cognitive and functional changes in Alzheimer's disease, particularly for APOE ε4 noncarriers, whereas antidepressants may be safer options for behavioral enhancement.

Vitis vinifera L. Flavones Regulate Hippocampal Neurons via Autophagy in APP/PS1 Alzheimer Model Mice

Background

Alzheimer's disease (AD) is a neurodegenerative disease and our current treatment approach can only delay its course rather than cure it completely. Flavones from Vitis vinifera L. have been reported to promote synaptic plasticity and indirectly affect the expression of cholinergic neurotransmitters in a rat model of Alzheimer's disease.

Objective

The aim of the study is to explore the effect of Vitis vinifera L. in APP/PS1 Alzheimer model mice.

Methods

APP/PS1 AD mice were used as the research subjects, and the mice were divided into a model group, donepezil group, VTF low-dose group, VTF medium-dose group, and VTF high-dose group. C57BL/6 mice served as a control group. The autophagosomes were observed by a transmission electron microscope, and the expressions of LC3I, LC3IIand Beclin-1 were determined by Western blotting. The results of qRT-PCR are consistent with Western blotting.

Results

VTF can exert a positive regulatory effect on AD mice by inhibiting autophagy.

Conclusion

Our study supports that intragastrically administration of VTF is effective and operable in Alzheimer's disease mice, and that inhibition of excessive autophagy may be one of the potential reasons why VTF exerts a therapeutic effect on AD.

Alzheimer Disease

PURPOSE OF REVIEW

Alzheimer disease (AD) is the most common cause of dementia in adults (mid to late life), highlighting the importance of understanding the risk factors, clinical manifestations, and recent developments in diagnostic testing and therapeutics.

RECENT FINDINGS

Advances in fluid (CSF and blood-based) and imaging biomarkers are allowing for a more precise and earlier diagnosis of AD (relative to non-AD dementias) across the disease spectrum and in patients with atypical clinical features. Specifically, tau- and amyloid-related AD pathologic changes can now be measured by CSF, plasma, and positron emission tomography (PET) with good precision. Additionally, a better understanding of risk factors for AD has highlighted the need for clinicians to address comorbidities to maximize prevention of cognitive decline in those at risk or to slow decline in patients who are symptomatic. Recent clinical trials of amyloid-lowering drugs have provided not only some optimism that amyloid reduction or prevention may be beneficial but also a recognition that addressing additional targets will be necessary for significant disease modification.

SUMMARY

Recent developments in fluid and imaging biomarkers have led to the improved understanding of AD as a chronic condition with a protracted presymptomatic phase followed by the clinical stage traditionally recognized by neurologists. As clinical trials of potential disease-modifying therapies continue, important developments in the understanding of the disease will improve clinical care now and lead to more effective therapies in the near future.

Transcranial Direct Current Stimulation (tDCS) as a Useful Rehabilitation Strategy to Improve Cognition in Patients With Alzheimer's Disease and Parkinson's Disease: An Updated Systematic Review of Randomized Controlled Trials

Alzheimer's disease (AD) and Parkinson's disease (PD) are neurodegenerative disorders characterized by cognitive impairment and functional decline increasing with disease progression. Within non-pharmacological interventions, transcranial direct current stimulation (tDCS) might represent a cost-effective rehabilitation strategy to implement cognitive abilities with positive implications for functional autonomy and quality-of-life of patients. Our systematic review aimed at evaluating the effects of tDCS upon cognition in people suffering from AD and PD. We searched for randomized controlled trials (RCTs) into PubMed, Web of Science, and Cochrane Library. Three review authors extracted data of interest, with neuropsychological tests or experimental cognitive tasks scores as outcome measures. A total of 17 RCTs (10 trials for AD and 7 trials for PD) were included. Compared with sham stimulation, tDCS may improve global cognition and recognition memory in patients with AD and also some executive functions (i.e., divided attention, verbal fluency, and reduction of sensitivity to interference) in patients with PD. Criticism remains about benefits for the other investigated cognitive domains. Despite preliminary emerging evidences, larger RCTs with common neuropsychological measures and long-term follow-ups establishing longevity of the observed effects are necessary for future research in applied psychology field, alongside improved clinical guidelines on the neurodegenerative disorders pertaining electrodes montage, sessions number, duration and intensity of the stimulation, and cognitive battery to be used.

Association between long-term donepezil treatment and brain regional amyloid and tau burden among individuals with mild cognitive impairment assessed using 18 F-AV-45 and 18 F-AV-1451 PET

This study aims to investigate the association between long-term donepezil treatment and brain neuropathological burden and cognitive function in mild cognitive impairment (MCI) patients. Preprocessed ¹⁸ F-AV-45 amyloid and ¹⁸ F-AV-1451 tau positron emission tomography (PET) images, magnetic resonance imaging images (MRIs), demographic information, and donepezil use status were downloaded from 255 MCI participants enrolled in the Alzheimer's Disease Neuroimaging Initiative database. Partial volume correction was applied to all PET images. Structural MRIs were used for PET spatial normalization. Regions of interest (ROIs) were defined in standard space, and standardized uptake value ratio (SUVR) images relative to the cerebellum were computed. Multiple linear regression with the least absolute shrinkage selector operator was performed to analyze the effect of long-term donepezil treatment on (a) the SUVR of each ¹⁸ F-AV-45 or ¹⁸ F-AV-1451 brain PET ROI after adjusting for age, sex, education, ApoE ε4 status, and AD-associated disease risk factors; and (b) cognitive performance after adjusting for age, sex education, ApoE ε4 status, AD-associated disease risk factors, and regional amyloid or tau burden. In adjusted models, long-term donepezil treatment was associated with greater amyloid load in the orbital frontal, superior frontal, parietal, posterior precuneus, posterior cingulate, lateral temporal, inferior temporal and fusiform regions, and tau burden in the posterior cingulate, entorhinal and parahippocampal gyrus. Long-term donepezil treatment was also associated with worse performance on the 13-item Alzheimer's Disease Assessment Scale-Cognitive subscale after adjusting for AD-related risk factors and regional brain amyloid or tau load. These results indicate that long-term donepezil treatment is associated with increased regional amyloid and tau burden and worse cognitive performance among individuals with MCI. Our study highlights the importance of using noninvasive and quantitative ¹⁸ F-AV-45 and ¹⁸ F-AV-1451 PET to elucidate the consequences of drug administration in AD studies.

Exercise priming with transcranial direct current stimulation: a study protocol for a randomized, parallel-design, sham-controlled trial in mild cognitive impairment and Alzheimer's disease

Background

Transcranial direct current stimulation (tDCS) is a non-invasive type of brain stimulation that uses electrical currents to modulate neuronal activity. A small number of studies have investigated the effects of tDCS on cognition in patients with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD), and have demonstrated variable effects. Emerging evidence suggests that tDCS is most effective when applied to active brain circuits. Aerobic exercise is known to increase cortical excitability and improve brain network connectivity. Exercise may therefore be an effective, yet previously unexplored primer for tDCS to improve cognition in MCI and mild AD.

Methods

Participants with MCI or AD will be randomized to receive 10 sessions over 2 weeks of either exercise primed tDCS, exercise primed sham tDCS, or tDCS alone in a blinded, parallel-design trial. Those randomized to an exercise intervention will receive individualized 30-min aerobic exercise prescriptions to achieve a moderate-intensity dosage, equivalent to the ventilatory anaerobic threshold determined by cardiopulmonary assessment, to sufficiently increase cortical excitability. The tDCS protocol consists of 20 min sessions at 2 mA, 5 times per week for 2 weeks applied through 35 cm² bitemporal electrodes. Our primary aim is to assess the efficacy of exercise primed tDCS for improving global cognition using the Montreal Cognitive Assessment (MoCA). Our secondary aims are to evaluate the efficacy of exercise primed tDCS for improving specific cognitive domains using various cognitive tests (n-back, Word Recall and Word Recognition Tasks from the Alzheimer’s Disease Assessment Scale-Cognitive subscale) and neuropsychiatric symptoms (Neuropsychiatric Inventory). We will also explore whether exercise primed tDCS is associated with an increase in markers of neurogenesis, oxidative stress and angiogenesis, and if changes in these markers are correlated with cognitive improvement.

Discussion

We describe a novel clinical trial to investigate the effects of exercise priming before tDCS in patients with MCI or mild AD. This proof-of-concept study may identify a previously unexplored, non-invasive, non-pharmacological combination intervention that improves cognitive symptoms in patients. Findings from this study may also identify potential mechanistic actions of tDCS in MCI and mild AD.

Trial registration

Clinicaltrials.gov, NCT03670615. Registered on September 13, 2018.

A nanocleaner specifically penetrates the blood‒brain barrier at lesions to clean toxic proteins and regulate inflammation in Alzheimer's disease

Insurmountable blood‒brain barrier (BBB) and complex pathological features are the key factors affecting the treatment of Alzheimer's disease (AD). Poor accumulation of drugs in lesion sites and undesired effectiveness of simply reducing Aβ deposition or TAU protein need to be resolved urgently. Herein, a nanocleaner is designed with a rapamycin-loaded ROS-responsive PLGA core and surface modification with KLVFF peptide and acid-cleavable DAG peptide [R@(ox-PLGA)-KcD]. DAG can enhance the targeting and internalization effect of nanocleaner towards neurovascular unit endothelial cells in AD lesions, and subsequently detach from nanocleaner in response to acidic microenvironment of endosomes to promote the transcytosis of nanocleaner from endothelial cells into brain parenchyma. Then exposed KLVFF can capture and carry Aβ to microglia, attenuating Aβ-induced neurotoxicity. Strikingly, rapamycin, an autophagy promoter, is rapidly liberated from nanocleaner in the high ROS level of lesions to improve Aβ degradation and normalize inflammatory condition. This design altogether accelerates Aβ degradation and alleviates oxidative stress and excessive inflammatory response. Collectively, our finding offers a strategy to target the AD lesions precisely and multi-pronged therapies for clearing the toxic proteins and modulating lesion microenvironment, to achieve efficient AD therapy.

Changes in the use of psychotropic drugs during the course of Alzheimer's disease: A large-scale longitudinal study of French medical records

INTRODUCTION

We aim to understand how patients with Alzheimer's disease (AD) are treated by identifying in a longitudinal fashion the late-life changes in patients' medical history that precede and follow AD diagnosis.

METHODS

We use prescription history of 34,782 patients followed between 1996 and 2019 by French general practitioners. We compare patients with an AD diagnosis, patients with mild cognitive impairment (MCI), and patients free of mental disorders. We use a generalized mixed-effects model to study the longitudinal changes in the prescription of eight drug types for a period 15 years before diagnosis and 10 years after.

RESULTS

In the decades preceding diagnosis, we find that future AD patients are treated significantly more than MCI patients with most psychotropic drugs and that most studied drugs are increasingly prescribed with age. At the time of diagnosis, all psychotropic drugs except benzodiazepines show a significant increase in prescription, while other drugs are significantly less prescribed. In the 10 years after diagnosis, nearly all categories of drugs are less and less prescribed including antidementia drugs.

DISCUSSION

Pre-diagnosis differences between future AD patients and MCI patients may indicate that subtle cognitive changes are recognized and treated as psychiatric symptoms. The disclosure of AD diagnosis drastically changes patients' care, priority being given to the management of psychiatric symptoms. The decrease of all prescriptions in the late stages may reflect treatment discontinuation and simplification of therapeutic procedures. This study therefore provides new insights into the medical practices for management of AD.

Improving Drug Delivery for Alzheimer's Disease Through Nose-to-Brain Delivery Using Nanoemulsions, Nanostructured Lipid Carriers (NLC) and in situ Hydrogels

Current treatments for Alzheimer's disease (AD) attenuate the progression of symptoms and aim to improve the patient's quality of life. Licensed medicines are mostly for oral administration and are limited by the difficulty in crossing the blood-brain barrier (BBB). Here in, the nasal route has been explored as an alternative pathway that allows drugs to be directly delivered to the brain via the nasal cavity. However, clearance mechanisms in the nasal cavity impair the delivery of drugs to the brain and limit their bioavailability. To optimize nose-to-brain delivery, formulations of lipid-based nanosystems, namely nanoemulsions and nanostructured lipid carriers (NLC), formulated in situ gelling hydrogels have been proposed as approaches for nose-to-brain delivery. These formulations possess characteristics that facilitate drug transport directly to the brain, minimizing side effects and maximizing therapeutic benefits. It has been recommended that the manufacture of these drug delivery systems follows the quality by design (QbD) approach based on nasal administration requirements. This review provides an insight into the current knowledge of the AD, highlighting the need for an effective drug delivery to the brain. Considering the mounting interest in the use of nanoemulsions and NLC for nose-to-brain delivery, a description of drug transport pathways in the nasal cavity and the application of these nanosystems and their in situ hydrogels through the intranasal route are presented. Relevant preclinical studies are summarised, and the future prospects for the use of lipid-based nanosystems in the treatment of AD are emphasized.

Biocomputational Screening of Natural Compounds against Acetylcholinesterase

Alzheimer's disease (AD) is the most common form of dementia and is characterized by irreversible and progressive neurodegeneration. Cholinergic dysfunction has been reported in AD, and several cholinesterase inhibitors, including natural compounds and synthetic analogs, have been developed to treat the disease. However, there is currently no treatment for AD, as most drug-like compounds have failed in clinical trials. Acetylcholinesterase (AChE) is the target of most drugs used commercially to treat AD. This work focused on screening natural compounds obtained from the ZINC database (224, 205 compounds) against AChE to identify those possibly capable of enabling the management of AD. Indirubin and dehydroevodiamine were the best potential AChE inhibitors with free binding energies of -10.03 and -9.00 kcal/mol, respectively. The key residue (His447) of the active site of AChE was found to participate in complex interactions with these two molecules. Six H-bonds were involved in the 'indirubin-AChE' interaction and three H-bonds in the 'dehydroevodiamine-AChE' interaction. These compounds were predicted to cross the blood-brain barrier (BBB) and to exhibit high levels of intestinal absorption. Furthermore, 'indirubin-AChE' and 'dehydroevodiamine-AChE' complexes were found to be stable, as determined by root mean square deviation (RMSD) during a 50 ns molecular dynamics simulation study. Based on the free binding energies and stabilities obtained by simulation studies, we recommend that experimental studies be undertaken on indirubin and dehydroevodiamine with a view towards their potential use as treatments for AD.

Diagnostic accuracy of the Clinical Dementia Rating Scale for detecting mild cognitive impairment and dementia: A bivariate meta-analysis

OBJECTIVE

The Clinical Dementia Rating (CDR) Scale comprising global score (CDR-GS) and sum of boxes scores (CDR-SB) is commonly used in staging cognitive impairment; however, its diagnostic accuracy is not well clarified. The meta-analysis aimed to investigate the diagnostic accuracy of the CDR for mild cognitive impairment (MCI) and dementia in older populations.

METHODS

Studies examining the diagnostic accuracy of the CDR for MCI or dementia against reference standards were included from seven electronic databases. The bivariate analysis with a random-effects model was adopted to calculate the pooled sensitivity and specificity of the CDR for MCI and dementia.

RESULTS

Fifteen studies investigating the diagnostic accuracy of the CDR-GS (n = 13) or CDR-SB (n = 5) for MCI or dementia were included. The pooled sensitivity and specificity of the CDR-GS for MCI were 93% and 97%, respectively. With respect to dementia, the CDR-GS had superior pooled specificity compared to the CDR-SB (99% vs. 94%), while similar sensitivities were found between the CDR-GS and CDR-SB (both 87%). Significant moderators of an old age, a high educational level, a high prevalence of MCI or dementia, being in a developing country, and a lack of informants' observations may affect the estimation of the sensitivity or specificity of the CDR.

CONCLUSIONS

Evidence supports the CDR being useful for detecting MCI and dementia; applying the CDR for staging cognitive impairment in at risk populations should be considered. Furthermore, including objective observations from relevant informants or proxies to increase the accuracy of the CDR for dementia is suggested.

Five novel and highly efficient endophytic fungi isolated from Huperzia serrata expressing huperzine A for the treatment of Alzheimer's disease

Huperzine A (Hup A) is an important drug for treating Alzheimer's disease (AD) and mainly extracted from the Huperzia serrata (Thunb.) Trevis. (Lycopodiaceae) (HS). Nevertheless, the content of Hup A in HS is very low of 0.007% with growing circle of 8 to 10 years, and the chemical synthesis of Hup A still has some insurmountable limitations in the industrialized production. So, the available resources of Hup A for clinical treatment of AD are scarce. The purpose of this work was to construct a biosynthesis platform based on the endophytic fungi from HS. In this work, five endophytic fungi Mucor racemosus NSH-D, Mucor fragilis NSY-1, Fusarium verticillioides NSH-5, Fusarium oxysporum NSG-1, and Trichoderma harzianum NSW-V were firstly found and isolated from the Chinese folk medicine HS, which were identified according to their morphological characteristics and nuclear ribosomal DNA ITS sequences. The highest efficient fungus could effectively biosynthesize Hup A in a liquid culture of 319.8 ± 0.17 mg/L which were 112 times higher than that of other reported conventional endophytic fungi. Moreover, these fungi with higher hereditary stability could possess the initial expressing ability of Hup A after 40 generations, and the expressed Hup A from these biosynthesis systems has prior physicochemical properties, a better inhibition activity of acetylcholinesterase and a lower cytotoxicity compared with the listed active pharmaceutical ingredients (APIs) of Hup A. These results provide promising alternative resources for producing Hup A at an industrial scale by biosynthesis, and it may also shed light on millions of AD patients. KEY POINTS: • Five novel endophytic fungi with high stability could highly express prior Hup A Graphical abstract.

Pharmacogenetic considerations when prescribing cholinesterase inhibitors for the treatment of Alzheimer's disease

INTRODUCTION

Cholinergic dysfunction, demonstrated in the late 1970s and early 1980s, led to the introduction of acetylcholinesterase inhibitors (AChEIs) in 1993 (Tacrine) to enhance cholinergic neurotransmission as the first line of treatment against Alzheimer's disease (AD). The new generation of AChEIs, represented by Donepezil (1996), Galantamine (2001) and Rivastigmine (2002), is the only treatment for AD to date, together with Memantine (2003). AChEIs are not devoid of side-effects and their cost-effectiveness is limited. An option to optimize the correct use of AChEIs is the implementation of pharmacogenetics (PGx) in the clinical practice.

AREAS COVERED

(i) The cholinergic system in AD, (ii) principles of AD PGx, (iii) PGx of Donepezil, Galantamine, Rivastigmine, Huperzine and other treatments, and (iv) practical recommendations.

EXPERT OPINION

The most relevant genes influencing AChEI efficacy and safety are APOE and CYPs. APOE-4 carriers are the worst responders to AChEIs. With the exception of Rivastigmine (UGT2B7, BCHE-K), the other AChEIs are primarily metabolized via CYP2D6, CYP3A4, and UGT enzymes, with involvement of ABC transporters and cholinergic genes (CHAT, ACHE, BCHE, SLC5A7, SLC18A3, CHRNA7) in most ethnic groups. Defective variants may affect the clinical response to AChEIs. PGx geno-phenotyping is highly recommended prior to treatment.

Initiation of symptomatic medication in Alzheimer's disease clinical trials: Hypothetical versus treatment policy approach

In clinical trials in populations with mild cognitive impairment, it is common for participants to initiate concurrent symptomatic medications for Alzheimer's disease after randomization to the experimental therapy. One strategy for addressing this occurrence is to exclude any observations that occur after the concurrent medication is initiated. The rationale for this approach is that these observations might reflect a symptomatic benefit of the concurrent medication that would adversely bias efficacy estimates for an effective experimental therapy. We interrogate the assumptions underlying such an approach by estimating the effect of newly prescribed concurrent medications in an observational study, the Alzheimer's Disease Neuroimaging Initiative.

Safety and efficacy of Jujadokseo-hwan for memory deficit (amnesia) in mild neurocognitive disorder: A protocol for randomized, double-blind, placebo-controlled, parallel-group, multicenter clinical trial

BACKGROUND

Mild neurocognitive disorder (mNCD) is one of the degenerative diseases that results in memory deficit, and can progress to dementia. The effectiveness of drug therapy for mNCD is still debatable, but treatment of this disease has important implications for postponing or preventing dementia. Jujadokseo-hwan (JDH) is a traditional herbal medicine formulation that exhibits improvement in cognitive abilities and neuroprotective effects. In this study, we will evaluate the safety and efficacy of JDH compared to placebo in mNCD patients.

METHODS AND DESIGN

This is a randomized, double-blind, placebo-controlled, parallel-group, multicenter clinical trial. After obtaining informed consent from all participants and performing the screening process, the participants will be equally divided into an experimental group and a control group. Each participant will visit the trial center 7 times during the 12 weeks of intervention. The follow up study will be conducted 12 weeks after the intervention ends. The primary outcome is the variance in Seoul verbal learning test-elderly's version (SVLT-E) score from baseline to 12 weeks. Secondary outcomes include scores/values for the following variables: SVLT-E, Rey complex figure test, Digit span test, Korean-Boston naming test, calculation ability, controlled oral word association test, Korean-color word stroop test, digit symbol coding, Korean-trail making test-elderly's version, Korean version of mini mental state examination for dementia screening, euro-qol-5 dimension, pattern identifications tool for cognitive disorders, Korean version of Montreal cognitive assessment, Korean quality of life-Alzheimer disease, computerized tongue image analysis system, blood pressure pulse analyzer, bioelectrical impedance analyzer, wearable electroencephalogram device, functional near-infrared spectroscopy system, and cost analysis.

DISCUSSION

This is the first trial evaluating the efficacy of JDH for mNCD. We expect this trial will provide strong support for wide use of JDH for mNCD and lead to further research on herbal medicine treatments for mNCD.

TRIAL REGISTRATION NUMBER

KCT0003570 (Registered in Clinical Research Information Service of the Republic of Korea, https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=12669).

Effects of computerised cognitive training on cognitive impairment: a meta-analysis

INTRODUCTION

Computerised cognitive training (CCT) has been shown to enhance cognitive function in elderly individuals with cognitive deterioration, but evidence is controversial. Additionally, whether specific CCT is most effective and which stages of cognitive impairment benefit most is unclear.

METHODS

We systematically searched nine medical and technological databases to collect randomized controlled trials related to CCT primarily conducted in patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI).

RESULTS

We identified 12 studies in patients with SCD and MCI. Pooled analysis showed that CCT could significantly improve cognitive function (g = 0.518, p = 0.000), especially related to memory. In terms of different types of cognitive training, specific CCT was more efficacious than non-specific CCT (g = 0.381, p = 0.007) or placebo (g = 0.734, p = 0.000) but not traditional CT (p = 0.628). In terms of stages of cognitive deterioration, the effect of CCT on SCD (g = 0.926, p = 0.002) was almost double that of its effect on MCI (g = 0.502, p = 0.000).

CONCLUSION

CCT was most effective in cognitive rehabilitation, particularly in the subdomain of memory. Early intervention in SCD is better.

Alzheimer Disease: An Update on Pathobiology and Treatment Strategies

Alzheimer disease (AD) is a heterogeneous disease with a complex pathobiology. The presence of extracellular β-amyloid deposition as neuritic plaques and intracellular accumulation of hyperphosphorylated tau as neurofibrillary tangles remains the primary neuropathologic criteria for AD diagnosis. However, a number of recent fundamental discoveries highlight important pathological roles for other critical cellular and molecular processes. Despite this, no disease-modifying treatment currently exists, and numerous phase 3 clinical trials have failed to demonstrate benefits. Here, we review recent advances in our understanding of AD pathobiology and discuss current treatment strategies, highlighting recent clinical trials and opportunities for developing future disease-modifying therapies.

The effects of acupuncture on cognitive deficits in transgenic mouse studies of mild cognitive impairment and Alzheimer's disease: Study protocol of a systematic review

BACKGROUND

Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are neurodegenerative diseases associated with aging. The major clinical features of both are progressive memory loss and progressive cognitive loss. The objective of this systematic review protocol is to provide the methods for evaluating the effectiveness of acupuncture in the treatment on cognitive deficits in transgenic mouse.

METHODS AND ANALYSIS

We will search the electronic databases of PubMed, Web of Science, Embase, PsycINFO, as well as the Chinese databases such as Chinese Biomedicine Literature (CBM), Chinese Medical Current Content (CMCC), Chinese Scientific Journal Database (VIP), WanFang Database and China National Knowledge Infrastructure (CNKI) from their inceptions to July 2019. RevMan 5.3 software will be used for the data synthesis and the quality of each study was assessed independently by use of the CAMARADES checklist.

RESULTS

This review will provide a high-quality synthesis based on present evidence of acupuncture treatment for AD and MCI in transgenic mouse models.

CONCLUSIONS

This systematic review will provide evidence for weather acupuncture is an effective intervention for AD and MCI in transgenic mouse models.

ETHICS AND DISSEMINATION

Ethical approval is not necessary since this protocol is only for systematic review and does not involve privacy data or conduct an animal experiment. This protocol will be disseminated by a peer-review journal or conference presentation.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42019142985.

STRENGTHS AND LIMITATIONS OF THIS STUDY

This systematic review will be the first to provide new knowledge underlying the effectiveness to improve cognitive function of acupuncture treatment for AD and MCI in transgenic mouse models. The result of this systematic review may provide experimental and theoretical basis for the future clinical application of acupuncture in the treatment of AD.The limitation of this systematic review may come from language barriers, because only English and Chinese can be included. Also, this study includes various kinds of acupuncture treatments which may result in essential heterogeneity.

Neuro-regeneration Therapeutic for Alzheimer's Dementia: Perspectives on Neurotrophic Activity

Alzheimer's disease (AD), the leading disorder of memory impairment in our aging population, is increasing at an alarming rate. AD is currently identified by three 'gold standard criteria': (i) dementia in life, (ii) amyloid plaques at autopsy, and (iii) neurofibrillary tangles at autopsy. Several autopsy studies have indicated that dementia in life is a consequence of lost synaptic networks in the brain, while many clinical trials targeting neurotoxic amyloid beta (Aβ) have consistently failed to produce therapeutic effects on memory function in AD patients. Restoring cognitive function(s) by activating endogenous repairing/regenerating mechanisms that are synaptogenic and antiapoptotic (preventing neuronal death), however, is emerging as a necessary disease-modifying therapeutic strategy against AD and possibly for other degenerative dementias, such as Parkinson's disease and multi-infarct dementia.