Do we still need animals? Surveying the role of animal-free models in Alzheimer's and Parkinson's disease research.

The use of animals in neuroscience and biomedical research remains controversial. Policy is built around the "3R" principle of "Refining, Reducing and Replacing" animal experiments, and across the globe, different initiatives stimulate the use of animal-free methods. Based on an extensive literature screen to map the development and adoption of animal-free methods in Alzheimer's and Parkinson's disease research, we find that at least two in three examined studies rely on animals or on animal-derived models. Among the animal-free studies, the relative contribution of innovative models that may replace animal experiments is limited. We argue that the distinction between animal research and alternative models presents a false dichotomy, as the role and scientific value of both animal and animal-free approaches are intertwined. Calls to halt all animal experiments appear premature, as insufficient non-animal-based alternatives are available and their development lags behind. In light of this, we highlight the need for objective, unprejudiced monitoring, and more robust performance indicators of animal-free approaches.

Harmonizing neuropsychological assessment for mild neurocognitive disorders in Europe.

INTRODUCTION: Harmonized neuropsychological assessment for neurocognitive disorders, an international priority for valid and reliable diagnostic procedures, has been achieved only in specific countries or research contexts. METHODS: To harmonize the assessment of mild cognitive impairment in Europe, a workshop (Geneva, May 2018) convened stakeholders, methodologists, academic, and non-academic clinicians and experts from European, US, and Australian harmonization initiatives. RESULTS: With formal presentations and thematic working-groups we defined a standard battery consistent with the U.S. Uniform DataSet, version 3, and homogeneous methodology to obtain consistent normative data across tests and languages. Adaptations consist of including two tests specific to typical Alzheimer's disease and behavioral variant frontotemporal dementia. The methodology for harmonized normative data includes consensus definition of cognitively normal controls, classification of confounding factors (age, sex, and education), and calculation of minimum sample sizes. DISCUSSION: This expert consensus allows harmonizing the diagnosis of neurocognitive disorders across European countries and possibly beyond.

Prolonged use of antipsychotic medications in long-term aged care in Australia: a snapshot from the HALT project.

OBJECTIVES: Use of antipsychotic drugs in long-term aged care (LTC) is prevalent and commonly exceeds the recommended duration, but contributors to this problem are not well understood. The objective of this study is to provide a snapshot of the features of and contributors to prolonged use of antipsychotic medications (>12 weeks) among a sample of LTC residents. DESIGN: We present retrospective and baseline data collected for the Australian Halting Antipsychotic Use in Long-Term Care (HALT) single-arm longitudinal deprescribing trial. SETTING: Twenty-four long-term care facilities in Sydney, Australia. PARTICIPANTS: The HALT study included 146 older people living in 24 Sydney LTC homes who had been prescribed a regular antipsychotic medication for at least 3 months at baseline. MEASUREMENTS: Detailed file audit was conducted to identify the date and indication recorded at initial prescription, consenting practices, longitudinal course of prescribing, and recommendations for review of antipsychotic medication. Behavioural and psychological symptoms of dementia (BPSD) and functional dependence at baseline were assessed via LTC staff interview. Cognition at baseline was assessed in a participant interview (where possible). RESULTS: Antipsychotics were prescribed for 2.2 years on average despite recommendations by a doctor or pharmacist for review in 62% of cases. Consent for antipsychotic prescription was accessible for only one case and contraindications for use were common. Longer use of antipsychotics was independently associated with higher dose of the antipsychotic drug and greater apathy, but not with other BPSD. CONCLUSION: Antipsychotic medications appeared to be prescribed in this sample as a maintenance treatment in the absence of active indicated symptoms and without informed consent. Standard interventions, including recommendations for review, had been insufficient to ensure evidence-based prescribing.

Why deprescribing antipsychotics in older people with dementia in long-term care is not always successful: Insights from the HALT study.

INTRODUCTION: Antipsychotic medications are commonly used to manage behavioural and psychological symptoms of dementia despite their side effects and harms. While the Halting Antipsychotic Use in Long-Term care (HALT) deprescribing trial was successful at reducing antipsychotic use, 19% of participants had their antipsychotics represcribed or never reached a dose of zero. The aim of this study was to investigate the reasons for represcription of antipsychotic medication and factors associated with ongoing antipsychotic use, relating to care staff requests and perceived behavioural changes. MATERIALS AND METHODS: Thirty-nine of 133 HALT participants never ceased their antipsychotic medication or were represcribed a regular or pro re nata (PRN) antipsychotic after initial deprescribing. The views of nursing staff, general practitioner, and family on the circumstances leading up to these outcomes were collected via a questionnaire-based approach. This information was triangulated with observation and detailed file audit (including progress notes, medical notes, medication charts, incident reports, and hospital discharge summaries). A consensus panel reconstructed the represcribing context. RESULTS: Nurses were the most common drivers of represcribing (63.2%), followed by family members (39.5%), GPs (23.7%), specialists (13.2%), and hospital staff (10.5%). There were multiple drivers for antipsychotic use in 46.2% of participants. Increased agitated and aggressive behaviours were the most commonly reported reasons for represcribing even though these changes were not identified over time on objective measures. Consent and dosage practices remained poor despite education. DISCUSSION: Nursing staff are the key drivers of deprescribing particularly in response to perceived worsening agitation and aggression among male residents. The train-the-trainer model used in the HALT trial may have been insufficient on its own to improve staff competence and confidence in applying nonpharmacological approaches when responding to behaviour change.

Antipsychotic Deprescription for Older Adults in Long-term Care: The HALT Study.

OBJECTIVES: Despite limited efficacy and significant safety concerns, antipsychotic medications are frequently used to treat behavioral and psychological symptoms of dementia (BPSD) in long-term residential care. This study evaluates the sustained reduction of antipsychotic use for BPSD through a deprescribing intervention and education of health care professionals. DESIGN: Repeated-measures, longitudinal, single-arm study. SETTING: Long-term residential care of older adults. PARTICIPANTS: Nursing staff from 23 nursing homes recruited 139 residents taking regular antipsychotic medication for ≥3 months, without primary psychotic illness, such as schizophrenia or bipolar disorder, or severe BPSD. INTERVENTION: An antipsychotic deprescribing protocol was established. Education of general practitioners, pharmacists, and residential care nurses focused on nonpharmacological prevention and management of BPSD. MEASUREMENTS: The primary outcome was antipsychotic use over 12-month follow-up; secondary outcomes were BPSD (Neuropsychiatric Inventory, Cohen-Mansfield Agitation Inventory, and social withdrawal) and adverse outcomes (falls, hospitalizations, and cognitive decline). RESULTS: The number of older adults on regular antipsychotics over 12 months reduced by 81.7% (95% confidence interval: 72.4-89.0). Withdrawal was not accompanied by drug substitution or a significant increase in pro-re-nata antipsychotic or benzodiazepine administration. There was no change in BPSD or in adverse outcomes. CONCLUSION: In a selected sample of older adults living in long-term residential care, sustained reduction in regular antipsychotic use is feasible without an increase of BPSD.

Effects of MCI subtype and reversion on progression to dementia in a community sample.

OBJECTIVE: We sought to understand the trajectory of mild cognitive impairment (MCI) better by examining longitudinally different MCI subtypes and progression to dementia and reversion to normal cognition in a community sample. METHODS: We evaluated the stability of MCI subtypes and risk of dementia over 4 biennial assessments as part of an ongoing prospective cohort study, the Sydney Memory and Ageing Study. RESULTS: While prevalence of MCI and different MCI subtypes remains relatively stable across all assessments, reversion from MCI and transitions between different MCI subtypes were common. Up to 46.5% of participants classified with MCI at baseline reverted at some point during follow-up. The majority (83.8%) of participants with incident dementia were diagnosed with MCI 2 years prior to their dementia diagnosis. Both reverters and participants with stable MCI were at an increased risk of progression to dementia compared to those without MCI at baseline (HR 6.4, p = 0.02, and HR 24.7, p < 0.001, respectively); however, the risk of dementia in participants with MCI who did not revert was higher than in reverters (HR 2.5, p = 0.01). This effect was specific to amnestic subtypes (MCI reverters vs nonreverters: amnestic MCI HR 3.3, p = 0.006; nonamnestic MCI: HR 1.3, p = 0.67). CONCLUSION: Our findings indicate that the relevance of reversion for progression risk depends on the MCI subtype. Subtype specificity and longitudinal characterization are required for the reliable identification of individuals at high risk of developing dementia.

A Comprehensive Review of the Quality and Feasibility of Dementia Assessment Measures: The Dementia Outcomes Measurement Suite.

The diagnosis of dementia and the management of its associated symptoms are aided by high-quality assessment tools. However, there is disagreement on the optimal tools among abundant alternatives and lack of consistent quality standards across the different domains of dementia-related change (ie, cognition, severity, function, behavioral and psychological symptoms, delirium, quality of life). Standardization is difficult because the relevance of a measurement tool for health professionals may depend on the clinical setting and on the dementia type and severity. To address this need, we conducted a comprehensive and clinically relevant evidence-based review of dementia-related tools and present a set of recommended tools, the Dementia Outcomes Measurement Suite. The review revealed that considerable development has occurred in terms of assessment of persons with mild cognitive impairment, executive dysfunction, cognitively mediated functional change, and apathy. More research is needed to develop and validate tools to assess health-related quality of life and specific symptoms of dementia including anxiety, wandering, and repetitive vocalizations. This extensive overview of the quality of different measures may serve as a guide for health professionals clinically and for researchers developing new or improved dementia assessment tools.

Operationalizing the Diagnostic Criteria for Mild Cognitive Impairment: The Salience of Objective Measures in Predicting Incident Dementia.

OBJECTIVE: Mild cognitive impairment (MCI) is considered an intermediate stage between normal aging and dementia. It is diagnosed in the presence of subjective cognitive decline and objective cognitive impairment without significant functional impairment, although there are no standard operationalizations for each of these criteria. The objective of this study is to determine which operationalization of the MCI criteria is most accurate at predicting dementia. DESIGN: Six-year longitudinal study, part of the Sydney Memory and Ageing Study. SETTING: Community-based. PARTICIPANTS: 873 community-dwelling dementia-free adults between 70 and 90 years of age. Persons from a non-English speaking background were excluded. MEASUREMENTS: Seven different operationalizations for subjective cognitive decline and eight measures of objective cognitive impairment (resulting in 56 different MCI operational algorithms) were applied. The accuracy of each algorithm to predict progression to dementia over 6 years was examined for 618 individuals. RESULTS: Baseline MCI prevalence varied between 0.4% and 30.2% and dementia conversion between 15.9% and 61.9% across different algorithms. The predictive accuracy for progression to dementia was poor. The highest accuracy was achieved based on objective cognitive impairment alone. Inclusion of subjective cognitive decline or mild functional impairment did not improve dementia prediction accuracy. CONCLUSIONS: Not MCI, but objective cognitive impairment alone, is the best predictor for progression to dementia in a community sample. Nevertheless, clinical assessment procedures need to be refined to improve the identification of pre-dementia individuals.

Apathy in Dementia: Systematic Review of Recent Evidence on Pharmacological Treatments.

Increasing recognition that apathy is one of the most prevalent behavioral and psychological symptoms of dementia and causes substantial caregiver distress has led to trials evaluating psychosocial and pharmacological treatments of apathy in dementia. We evaluated evidence of the efficacy of pharmacotherapies for apathy in dementia from studies since 2013. Previously reported benefits of acetylcholinesterase inhibitors and memantine were not replicated in recent studies. Antidepressants had mixed results with positive effects for apathy shown only for agomelatine, while stimulants, analgesics, and oxytocin study results were inconclusive. For some approaches, such as antipsychotic review, positive effects were found only in combination with nonpharmacological approaches. Relatively few studies assessed apathy outcomes specifically, complicating interpretation of potentially positive treatment effects; none dissected outcomes for emotional, motivational and behavioral components of apathy. Better trial design and more detailed analysis are needed in order to evaluate outcomes of pharmacological treatments for apathy.

In Vitro Comparison of the Activity Requirements and Substrate Specificity of Human and Triboleum castaneum PINK1 Orthologues.

Mutations in the gene encoding the mitochondrial kinase PINK1 cause early-onset familial Parkinson's disease. To understand the biological function of PINK1 and its role in the pathogenesis of Parkinson's disease, it is useful to study its kinase activity towards substrates both in vivo and in vitro. For in vitro kinase assays, a purified Triboleum castaneum PINK1 insect orthologue is often employed, because it displays higher levels of activity when compared to human PINK1. We show, however, that the activity requirements, and more importantly the substrate specificity, differ between both orthologues. While Triboleum castaneum PINK1 readily phosphorylates the PINKtide peptide and Histone H1 in vitro, neither of these non-physiological substrates is phosphorylated by human PINK1. Nonetheless, both Tc and human PINK1 phosphorylate Parkin and Ubiquitin, two physiological substrates of PINK1. Our results show that the substrate selectivity differs among PINK1 orthologues, an important consideration that should be taken into account when extrapolating findings back to human PINK1.

PINK1 activation-turning on a promiscuous kinase.

PINK1 [phosphatase and tensin homologue (PTEN)-induced putative kinase 1] is a serine/threonine kinase targeted to mitochondria and implicated in early-onset recessive Parkinson's disease (PD). Through the phosphorylation of its downstream targets, PINK1 regulates multiple mitochondrial processes, including ATP production, stress-response and mitochondrial dynamics and quality control. The orchestration of such a wide array of functions by an individual kinase requires a fine-tuned and versatile regulation of its activity. PINK1 proteolytic processing, trafficking and localization, as well as different post-translational modifications, affect its activity and function. Unravelling the regulatory mechanisms of PINK1 is essential for a full comprehension of its kinase function in health and disease.

PINK1 kinase catalytic activity is regulated by phosphorylation on serines 228 and 402.

Mutations in the PINK1 gene cause early-onset recessive Parkinson disease. PINK1 is a mitochondrially targeted kinase that regulates multiple aspects of mitochondrial biology, from oxidative phosphorylation to mitochondrial clearance. PINK1 itself is also phosphorylated, and this might be linked to the regulation of its multiple activities. Here we systematically analyze four previously identified phosphorylation sites in PINK1 for their role in autophosphorylation, substrate phosphorylation, and mitophagy. Our data indicate that two of these sites, Ser-228 and Ser-402, are autophosphorylated on truncated PINK1 but not on full-length PINK1, suggesting that the N terminus has an inhibitory effect on phosphorylation. We furthermore establish that phosphorylation of these PINK1 residues regulates the phosphorylation of the substrates Parkin and Ubiquitin. Especially Ser-402 phosphorylation appears to be important for PINK1 function because it is involved in Parkin recruitment and the induction of mitophagy. Finally, we identify Thr-313 as a residue that is critical for PINK1 catalytic activity, but, in contrast to previous reports, we find no evidence that this activity is regulated by phosphorylation. These data clarify the regulation of PINK1 through multisite phosphorylation.

PINK1 loss-of-function mutations affect mitochondrial complex I activity via NdufA10 ubiquinone uncoupling.

Under resting conditions, Pink1 knockout cells and cells derived from patients with PINK1 mutations display a loss of mitochondrial complex I reductive activity, causing a decrease in the mitochondrial membrane potential. Analyzing the phosphoproteome of complex I in liver and brain from Pink1(-/-) mice, we found specific loss of phosphorylation of serine-250 in complex I subunit NdufA10. Phosphorylation of serine-250 was needed for ubiquinone reduction by complex I. Phosphomimetic NdufA10 reversed Pink1 deficits in mouse knockout cells and rescued mitochondrial depolarization and synaptic transmission defects in pink(B9)-null mutant Drosophila. Complex I deficits and adenosine triphosphate synthesis were also rescued in cells derived from PINK1 patients. Thus, this evolutionary conserved pathway may contribute to the pathogenic cascade that eventually leads to Parkinson's disease in patients with PINK1 mutations.

VEGF mediates commissural axon chemoattraction through its receptor Flk1.

Growing axons are guided to their targets by attractive and repulsive cues. In the developing spinal cord, Netrin-1 and Shh guide commissural axons toward the midline. However, the combined inhibition of their activity in commissural axon turning assays does not completely abrogate turning toward floor plate tissue, suggesting that additional guidance cues are present. Here we show that the prototypic angiogenic factor VEGF is secreted by the floor plate and is a chemoattractant for commissural axons in vitro and in vivo. Inactivation of Vegf in the floor plate or of its receptor Flk1 in commissural neurons causes axon guidance defects, whereas Flk1 blockade inhibits turning of axons to VEGF in vitro. Similar to Shh and Netrin-1, VEGF-mediated commissural axon guidance requires the activity of Src family kinases. Our results identify VEGF and Flk1 as a novel ligand/receptor pair controlling commissural axon guidance.