Dementia with Lewy Bodies Drug Therapies in Clinical Trials: Systematic Review up to 2022

INTRODUCTION

Reviews of randomized clinical trials (RCTs) in dementia with Lewy bodies (DLB) are essential for informing ongoing research efforts of symptomatic therapies and potentially disease-modifying therapies (DMTs).

METHODS

We performed a systematic review of all clinical trials conducted until September 27, 2022, by examining 3 international registries: ClinicalTrials.gov, the European Union Drug Regulating Authorities Clinical Trials Database, and the International Clinical Trials Registry Platform, to identify drugs in trials in DLB.

RESULTS

We found 25 agents in 40 trials assessing symptomatic treatments and DMTs for DLB: 7 phase 3, 31 phase 2, and 2 phase 1 trials. We found an active pipeline for drug development in DLB, with most ongoing clinical trials in phase 2. We identified a recent trend towards including participants at the prodromal stages, although more than half of active clinical trials will enroll mild to moderate dementia patients. Additionally, repurposed agents are frequently tested, representing 65% of clinical trials.

CONCLUSION

Current challenges in DLB clinical trials include the need for disease-specific outcome measures and biomarkers, and improving representation of global and diverse populations.

Characterization of Depressive Symptoms in Dementia and Examination of Possible Risk Factors

Background

Depression in individuals with Alzheimer's disease (AD) is common, distressing, difficult to treat, and inadequately understood. It occurs more frequently in AD than in older adults without dementia. The reasons why some patients develop depression during AD and others do not remain obscure.

Objective

We aimed to characterize depression in AD and to identify risk factors.

Methods

We used data from three large dementia focused cohorts: ADNI (n = 665 with AD, 669 normal cognition), NACC (n = 698 with AD, 711 normal cognition), and BDR (n = 757 with AD). Depression ratings were available using the GDS and NPI and in addition for BDR the Cornell. A cut-off of≥8 was used for the GDS and the Cornell Scale for Depression in Dementia,≥6 for the NPI depression sub-scale, and≥2 for the NPI-Q depression sub-scale. We used logistic regression to examine potential risk factors and random effects meta-analysis and an interaction term to look for interactions between each risk factor and the presence of cognitive impairment.

Results

In individual studies there was no evidence of a difference in risk factors for depressive symptoms in AD. In the meta-analysis the only risk factor which increased the risk of depressive symptoms in AD was previous depression, but information on this was only available from one study (OR 7.78 95% CI 4.03-15.03).

Conclusion

Risk factors for depression in AD appear to differ to those for depression per se supporting suggestions of a different pathological process, although a past history of depression was the strongest individual risk factor.

Persistent depressive symptoms are associated with frontal regional atrophy in patients with Alzheimer's disease

BACKGROUND

Depression in individuals with Alzheimer's disease (AD) is common, difficult to treat and inadequately understood. Previous studies have identified possible differences in regional brain atrophy in individuals with AD and depression, but the results have been inconsistent and some studies had less robust definitions of depression. We aimed to examine regional brain atrophy in two large dementia focused cohorts.

METHODS

We used data from Alzheimer's disease neuroimaging initiative (ADNI) and the National Alzheimer's Co-ordinating Center (NACC), for those with data from at least one MRI scan. Depression ratings were available using the Geriatric Depression Scale (GDS) and Neuropsychiatric Inventory (NPI). Intermittent depressive symptoms were defined as one episode above threshold (≥8 on GDS, ≥6 on NPI depression subscale and ≥2 on the Neuropsychiatric Inventory version Q depression sub-scale) and persistent as ≥2 episodes. Derived regional volumetric data was available from ADNI and the NACC.

RESULTS

Data was available from 698 individuals with AD in NACC and from 666 individuals in ADNI. We found no evidence of between group differences in regional brain volume at baseline, or of differential atrophy in NACC. In ADNI we found evidence of increased brain atrophy in several frontal brain areas.

LIMITATIONS

Because this study was limited to those with MRI data, the numbers in some analyses were low. MRI parcellation differed between studies making direct comparison difficult. For some individuals only the NPI was used to rate depression.

CONCLUSIONS

We have found mixed evidence of increased regional atrophy in depression in AD, mainly in frontal brain regions. We found no evidence to support a vascular basis for depression in AD.

Efficacy results of pimavanserin from a multi-center, open-label extension study in Parkinson's disease psychosis patients

INTRODUCTION

Pimavanserin, a selective 5-HT_2A inverse agonist/antagonist, was approved for hallucinations and delusions associated with Parkinson's disease psychosis (PDP). We present durability of response with pimavanserin in patients with PDP for an additional 4 weeks of treatment.

METHODS

This was an open-label extension (OLE) study in patients previously completing one of three double-blind, placebo-controlled (Core) studies. All patients received pimavanserin 34 mg once daily. Efficacy assessments included the Scale for the Assessment of Positive Symptoms (SAPS) PD and H + D scales, Clinical Global Impression (CGI) Improvement and Severity scales and Caregiver Burden Scale (CBS), through 4 weeks in the OLE. Safety assessments were conducted at each visit.

RESULTS

Of 459 patients, 424 (92.4%) had a Week 4 efficacy assessment. At Week 4 (10 weeks total treatment), SAPS-PD mean (standard deviation) change from OLE baseline was -1.8 (5.5) and for SAPS-H + D was -2.1 (6.2) with pimavanserin 34 mg. Patients receiving placebo during the Core studies had greater improvements (SAPS-PD -2.9 [5.6]; SAPS-H + D -3.5 [6.3]) during the OLE. For participants treated with pimavanserin 8.5 or 17 mg during the Core studies, further improvement was observed during the OLE with pimavanserin 34 mg. The mean change from Core Study baseline for SAPS-PD score was similar among prior pimavanserin 34 mg and prior placebo-treated participants (-7.1 vs. -7.0). The CGI-I response rate (score of 1 or 2) at Week 4 was 51.4%. Adverse events were reported by 215 (46.8%) patients during the first 4 weeks of OLE. The most common AEs were fall (5.9%), hallucination (3.7%), urinary tract infection (2.8%), insomnia (2.4%), and peripheral edema (2.2%) CONCLUSIONS: Patients previously on pimavanserin 34 mg during three blinded core studies had durability of efficacy during the subsequent 4 week OLE SAPS-PD assessment. Patients previously on blinded placebo improved after 4 weeks of OL pimavanserin treatment. These results in over 400 patients from 14 countries support the efficacy of pimavanserin for treating PDP.

Evaluation of the efficacy of pimavanserin in the treatment of agitation and aggression in patients with Alzheimer's disease psychosis: A post hoc analysis

OBJECTIVES

Patients with Alzheimer's disease psychosis (ADP) commonly experience concomitant agitation and aggression. We investigated whether a reduction in ADP following pimavanserin treatment conferred a reduction in associated agitation and aggression.

METHODS

ACP-103-019 was a 12-week, randomized, double-blind, placebo-controlled study that evaluated the efficacy of pimavanserin (34 mg) in reducing psychotic symptoms in patients with ADP. The primary endpoint was change from baseline in Neuropsychiatric Inventory-Nursing Home Version-Psychosis Score (NPI-NH-PS) at week six. A post hoc analysis examined whether there was a greater reduction in agitation and aggression (NPI-NH domain C [agitation/aggression] and Cohen-Mansfield Agitation Inventory-Short Form [CMAI-SF]) in pimavanserin-treated patients who experienced a reduction of hallucinations and delusions (psychosis responders defined as ≥50% reduction from baseline in NPI-NH-PS, week six) when compared with those who did not (nonresponders).

RESULTS

Pimavanserin-treated patients with ≥50% response in psychotic symptoms (n = 44) showed a greater improvement in agitation and aggression symptoms on the NPI-NH domain C (week six, least squares mean [LSM] difference = -3.64, t = -4.69, P < .0001) and the CMAI-SF (week six, LSM difference = -3.71, t = -2.01, P = .0483) than nonresponders (n = 32). Differences between psychosis responders and nonresponders were also observed in patients with more severe agitation and aggression at baseline on the NPI-NH domain C (responders, n = 26; nonresponders, n = 13; week six, LSM difference = -3.03, t = -2.44, P = .019).

CONCLUSIONS

Patients with ADP, who show improvement in psychotic symptoms after pimavanserin treatment, also experience an improvement in concomitant agitation and aggression.

Patterns of Mitochondrial TSPO Binding in Cerebral Small Vessel Disease: An in vivo PET Study With Neuropathological Comparison

Small vessel disease (SVD) is associated with cognitive impairment in older age and be implicated in vascular dementia. Post-mortem studies show proliferation of activated microglia in the affected white matter. However, the role of inflammation in SVD pathogenesis is incompletely understood and better biomarkers are needed. We hypothesized that expression of the 18 kDa translocator protein (TSPO), a marker of microglial activation, would be higher in SVD. Positron emission tomography (PET) was performed with the second-generation TSPO ligand [11C]PBR28 in 11 participants with SVD. TSPO binding was evaluated by a two-tissue compartment model, with and without a vascular binding component, in white matter hyperintensities (WMH) and normal-appearing white matter (NAWM). In post-mortem tissue, in a separate cohort of individuals with SVD, immunohistochemistry was performed for TSPO and a pan-microglial marker Iba1. Kinetic modeling showed reduced tracer volume and blood volume fraction in WMH compared with NAWM, but a significant increase in vascular binding. Vascular [11C]PBR28 binding was also increased compared with normal-appearing white matter of healthy participants free of SVD. Immunohistochemistry showed a diffuse increase in microglial staining (with Iba1) in sampled tissue in SVD compared with control samples, but with only a subset of microglia staining positively for TSPO. Intense TSPO staining was observed in the vicinity of damaged small blood vessels, which included perivascular macrophages. The results suggest an altered phenotype of activated microglia, with reduced TSPO expression, in the areas of greatest white matter ischemia in SVD, with implications for the interpretation of TSPO PET studies in older individuals or those with vascular risk factors.

Temporal Relationship Between Depressive Symptoms and Cognition in Mid and Late Life: A Longitudinal Cohort Study

OBJECTIVES

To examine the bidirectional temporal relationship between depressive symptoms and cognition in relation to risk, reaction, and prodrome.

DESIGN

Cross-lag analysis of longitudinal data collected online at baseline and 12-month follow-up.

SETTING AND PARTICIPANTS

A United Kingdom population cohort of 11,855 participants aged 50 years and over.

MEASURES

Patient Health Questionnaire-9 (depressive symptoms), cognitive measures: Paired Associate Learning, Verbal Reasoning, Spatial Working Memory, and Digit Span.

RESULTS

Depressive symptoms predicted a decline in paired associates learning [β = -.020, P = .013, (95% confidence interval [CI], ‒.036, -.004)] and verbal reasoning [β = -.014, P = .016, (95% CI ‒.025, -.003)] but not vice versa. Depressive symptoms predicted [β = -.043, P < .001, (95% CI ‒.060, -.026); β = -.029, P < .001, (95% CI ‒.043, -.015)] and were predicted by [β = -.030, P = < .001, (95% CI ‒.047, -.014); β = -.025, P = .003, (95% CI ‒.041, -.009)], a decline in spatial working memory and verbal digit span, respectively.

CONCLUSIONS AND IMPLICATIONS

Depressive symptoms may be either a risk factor or prodrome for cognitive decline. In addition, a decline in attention predicts depressive symptoms. Clinical implications and implications for further research are discussed.

Polygenic Risk Scoring is an Effective Approach to Predict Those Individuals Most Likely to Decline Cognitively Due to Alzheimer's Disease

BACKGROUND

There is a clear need for simple and effective tests to identify individuals who are most likely to develop Alzheimer's Disease (AD) both for the purposes of clinical trial recruitment but also for improved management of patients who may be experiencing early pre-clinical symptoms or who have clinical concerns.

OBJECTIVES

To predict individuals at greatest risk of progression of cognitive impairment due to Alzheimer's Disease in individuals from the Alzheimer's Disease Neuroimaging Initiative (ADNI) using a polygenic risk scoring algorithm. To compare the performance of a PRS algorithm in predicting cognitive decline against that of using the pTau/Aß1-42 ratio CSF biomarker profile.

DESIGN

A longitudinal analysis of data from the Alzheimer's Disease Neuroimaging Initiative study conducted across over 50 sites in the US and Canada.

SETTING

Multi-center genetics study.

PARTICPANTS

515 subjects who upon entry to the study were diagnosed as cognitively normal or with mild cognitive impairment.

MEASUREMENTS

Use of genotyping and/or whole genome sequencing data to calculate polygenic risk scores and assess ability to predict subsequent cognitive decline as measured by CDR-SB and ADAS-Cog13 over 4 years.

RESULTS

The overall performance for predicting those individuals who would decline by at least 15 ADAS-Cog13 points from a baseline mild cognitive impairment in 4 years was 72.8% (CI:67.9-77.7) AUC increasing to 79.1% (CI: 75.6-82.6) when also including cognitively normal participants. Assessing mild cognitive impaired subjects only and using a threshold of greater than 0.6, the high genetic risk participant group declined, on average, by 1.4 points (CDR-SB) more than the low risk group over 4 years. The performance of the PRS algorithm tested was similar to that of the pTau/Aß1-42 ratio CSF biomarker profile in predicting cognitive decline.

CONCLUSION

Calculating polygenic risk scores offers a simple and effective way, using DNA extracted from a simple mouth swab, to select mild cognitively impaired patients who are most likely to decline cognitively over the next four years.

Mitochondrial Translocase of the Outer Membrane Alterations May Underlie Dysfunctional Oxidative Phosphorylation in Alzheimer's Disease

BACKGROUND

The translocase of the outer membrane (TOM) is a vital mitochondrial transport system facilitating the importation of nuclear encoded proteins into the organelle. While mitochondrial dysfunction, including perturbation of oxidative phosphorylation (OXPHOS) complex, is evident in Alzheimer's disease (AD), it remains unclear whether the observed OXPHOS deficits may be associated with TOM alterations.

OBJECTIVES

To correlate TOM subunits with OXPHOS complex proteins in AD.

METHODS

Postmortem neocortex (BA40) from AD and age-matched controls were processed to obtain mitochondrial enriched homogenates for the measurement of Tom20, Tom22, Tom40, and Tom70 as well as components of OXPHOS complex I-V by immunoblotting.

RESULTS

Tom20 and Tom70 immunoreactivities were significantly reduced in AD, as were components of OXPHOS complex I and III. Both Tom20 and Tom70 positively correlated with complex III and V, while Tom20 also correlated withcomplex IV.

CONCLUSION

Reductions in certain TOM subunits and their correlations with specific OXPHOS complex proteins suggest that an impaired mitochondrial transportation system may contribute to previously observed oxidative phosphorylation deficits in AD. Follow-up studies are needed to corroborate the present correlative study.

Ras-ERK-ETS inhibition alleviates neuronal mitochondrial dysfunction by reprogramming mitochondrial retrograde signaling

Mitochondrial dysfunction activates the mitochondrial retrograde signaling pathway, resulting in large scale changes in gene expression. Mitochondrial retrograde signaling in neurons is poorly understood and whether retrograde signaling contributes to cellular dysfunction or is protective is unknown. We show that inhibition of Ras-ERK-ETS signaling partially reverses the retrograde transcriptional response to alleviate neuronal mitochondrial dysfunction. We have developed a novel genetic screen to identify genes that modify mitochondrial dysfunction in Drosophila. Knock-down of one of the genes identified in this screen, the Ras-ERK-ETS pathway transcription factor Aop, alleviates the damaging effects of mitochondrial dysfunction in the nervous system. Inhibition of Ras-ERK-ETS signaling also restores function in Drosophila models of human diseases associated with mitochondrial dysfunction. Importantly, Ras-ERK-ETS pathway inhibition partially reverses the mitochondrial retrograde transcriptional response. Therefore, mitochondrial retrograde signaling likely contributes to neuronal dysfunction through mis-regulation of gene expression.

Loss of mitochondrial function activates the mitochondrial retrograde signaling pathway resulting in large scale changes in nuclear gene transcription. Very little is known about retrograde signaling in the nervous system and how the transcriptional changes affect neuronal function. Here we identify Ras-ERK-ETS signaling as a novel mitochondrial retrograde signaling pathway in the Drosophila nervous system. Inhibition of Ras-ERK-ETS signaling improves neuronal function in Drosophila models of mitochondrial disease. Targeting Ras-ERK-ETS signaling may therefore have therapeutic potential in mitochondrial disease patients. Using a transcriptomic approach, we find that inhibition of Ras-ERK-ETS signaling partially reverses the mitochondrial retrograde transcriptional response. Surprisingly therefore, the mitochondrial retrograde transcriptional response contributes to neuronal dysfunction.

Increased Transforming Growth Factor β2 in the Neocortex of Alzheimer's Disease and Dementia with Lewy Bodies is Correlated with Disease Severity and Soluble Aβ42 Load

BACKGROUND

Of the three transforming growth factor (TGF)-β isoforms known, TGFβ1 deficits have been widely reported in Alzheimer's disease (AD) and studied as a potential therapeutic target. In contrast, the status of TGFβ2, which has been shown to mediate amyloid-β (Aβ)-mediated neuronal death, are unclear both in AD and in Lewy body dementias (LBD) with differential neuritic plaque and neurofibrillary tangle burden.

OBJECTIVE

To measure neocortical TGFβ2 levels and their correlations with neuropathological and clinical markers of disease severity in a well-characterized cohort of AD as well as two clinical subtypes of LBD, dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), known to manifest relatively high and low Aβ plaque burden, respectively.

METHODS

Postmortem samples from temporal cortex (BA21) were measured for TGFβ2 using a Luminex-based platform, and correlated with scores for neuritic plaques, neurofibrillary tangles, α-synuclein pathology, dementia severity (as measured by annual decline of Mini-Mental State Examination scores) as well as soluble and total fractions of brain Aβ42.

RESULTS

TGFβ2 was significantly increased in AD and DLB, but not in PDD. TGFβ2 also correlated with scores for neurofibrillary tangles, Lewy bodies (within the LBD group), dementia severity, and soluble Aβ42 concentration, but not with neuritic plaque scores, total Aβ42, or monomeric α-synuclein immunoreactivity.

CONCLUSIONS

TGFβ2 is increased in the temporal cortex of AD and DLB, and its correlations with neuropathological and clinical markers of disease severity as well as with soluble Aβ42 load suggest a potential pathogenic role in mediating the neurotoxicity of non-fibrillar Aβ. Our study also indicates the potential utility of targeting TGFβ2 in pharmacotherapeutic approaches to AD and DLB.

Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium

The Dementia with Lewy Bodies (DLB) Consortium has refined its recommendations about the clinical and pathologic diagnosis of DLB, updating the previous report, which has been in widespread use for the last decade. The revised DLB consensus criteria now distinguish clearly between clinical features and diagnostic biomarkers, and give guidance about optimal methods to establish and interpret these. Substantial new information has been incorporated about previously reported aspects of DLB, with increased diagnostic weighting given to REM sleep behavior disorder and ¹²³iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. The diagnostic role of other neuroimaging, electrophysiologic, and laboratory investigations is also described. Minor modifications to pathologic methods and criteria are recommended to take account of Alzheimer disease neuropathologic change, to add previously omitted Lewy-related pathology categories, and to include assessments for substantia nigra neuronal loss. Recommendations about clinical management are largely based upon expert opinion since randomized controlled trials in DLB are few. Substantial progress has been made since the previous report in the detection and recognition of DLB as a common and important clinical disorder. During that period it has been incorporated into DSM-5, as major neurocognitive disorder with Lewy bodies. There remains a pressing need to understand the underlying neurobiology and pathophysiology of DLB, to develop and deliver clinical trials with both symptomatic and disease-modifying agents, and to help patients and carers worldwide to inform themselves about the disease, its prognosis, best available treatments, ongoing research, and how to get adequate support.

Decreased Levels of VAMP2 and Monomeric Alpha-Synuclein Correlate with Duration of Dementia

Alpha-synuclein (α-syn) aggregations are the key pathological hallmark of dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), but are also frequently present in Alzheimer's disease (AD). Much remains unknown about the role of α-syn in the synapse and the wider role of synaptic dysfunction in these dementias. Changes in concentrations of key 'SNAP (Soluble N-ethylmaleimide Sensitive Factor Attachment Protein) Receptor' (SNARE) proteins as a consequence of alterations in the aggregation state of α-syn may contribute to synaptic dysfunction in patients with DLB, PDD, and AD and result in impaired cognition. We have studied a large cohort (n = 130) of autopsy confirmed DLB, PDD, AD, and control brains. Using semi-quantitative western blotting, we have demonstrated significant changes across the diagnostic groups of DLB, PDD, and AD in the SNARE and vesicle proteins syntaxin, Munc18, VAMP2, and monomeric α-syn in the prefrontal cortex, with a significant reduction of Munc18 in AD patients (p <  0.001). This correlated to the final MMSE score before death (p = 0.016). We also identified a significant negative correlation between the duration of dementia and the levels of the binding partners VAMP2 (p = 0.0004) and monomeric α-syn (p = 0.0002). Our findings may indicate that an upregulation of SNARE complex related proteins occurs in the early stages of disease as an attempt at compensating for failing synapses, prior to widespread deposition of pathological α-syn.

Increased phosphorylation of collapsin response mediator protein-2 at Thr514 correlates with β-amyloid burden and synaptic deficits in Lewy body dementias

Collapsin response mediator protein-2 (CRMP2) regulates axonal growth cone extension, and increased CRMP2 phosphorylation may lead to axonal degeneration. Axonal and synaptic pathology is an important feature of Lewy body dementias (LBD), but the state of CRMP2 phosphorylation (pCRMP2) as well as its correlations with markers of neurodegeneration have not been studied in these dementias. Hence, we measured CRMP2 phosphorylation at Thr509, Thr514 and Ser522, as well as markers of β-amyloid (Aβ), tau-phosphorylation, α-synuclein and synaptic function in the postmortem neocortex of a longitudinally assessed cohort of LBD patients characterized by low (Parkinson’s disease dementia, PDD) and high (dementia with Lewy bodies, DLB) burden of Alzheimer type pathology. We found specific increases of pCRMP2 at Thr514 in DLB, but not PDD. The increased CRMP2 phosphorylation correlated with fibrillogenic Aβ as well as with losses of markers for axon regeneration (β-III-tubulin) and synaptic integrity (synaptophysin) in LBD. In contrast, pCRMP2 alterations did not correlate with tau-phosphorylation or α-synuclein, and also appear unrelated to immunoreactivities of putative upstream kinases glycogen synthase kinase 3β and cyclin-dependent kinase 5, as well as to protein phosphatase 2A. In conclusion, increased pCRMP2 may underlie the axonal pathology of DLB, and may be a novel therapeutic target. However, antecedent signaling events as well as the nature of pCRMP2 association with Aβ and other neuropathologic markers require further study.

Dementia in Parkinson's disease is associated with enhanced mitochondrial complex I deficiency

BACKGROUND

Dementia is a common feature of Parkinson's disease (PD), but the neuropathological changes associated with the development of Parkinson's disease dementia (PDD) are only partially understood. Mitochondrial dysfunction is a hallmark of PD but has not been studied in PDD.

METHODS

Molecular and biochemical approaches were used to study mitochondrial activity and quantity in postmortem prefrontal cortex tissue. Tissues from pathologically confirmed PD and PDD patients and from age-matched controls were used to analyze the activity of mitochondrial enzyme complex nicotinamide adenine dinucleotide:ubiquinone oxidoreductase, or complex I (the first enzyme in the mitochondrial respiratory chain), mitochondrial DNA levels, and the expression of mitochondrial proteins.

RESULTS

Complex I activity was significantly decreased (27% reduction; analysis of variance with Tukey's post hoc test; P < 0.05) in PDD patients, and mitochondrial DNA levels were also significantly decreased (18% reduction; Kruskal-Wallis analysis of variance with Dunn's multiple comparison test; P < 0.05) in PDD patients compared with controls, but neither was significantly reduced in PD patients. Overall, mitochondrial biogenesis was unaffected in PD or PDD, because the expression of mitochondrial proteins in patients was similar to that in controls.

CONCLUSIONS

Patients with PDD have a deficiency in mitochondrial complex I activity and reduced mitochondrial DNA levels in the prefrontal cortex without a change in mitochondrial protein quantity. Therefore, mitochondrial complex I deficiency and reduced mitochondrial DNA in the prefrontal cortex may be a hallmark of dementia in patients with PD.

Butyrylcholinesterase: impact on symptoms and progression of cognitive impairment

The most successful approach for treating people with Alzheimer's disease to date has been by improving cholinergic transmission using cholinesterase inhibitors. Many of these drugs selectively inhibit acetylcholinesterase but some agents inhibit both acetylcholinesterase and butyrylcholinesterase. Recent evidence from studies examining butyrylcholinesterase in post mortem brain samples from dementia patients and examining the relationship between butyrylcholinesterase polymorphisms and the progression of cognitive impairment in dementia with Lewy bodies and Alzheimer's disease add to a body of work suggesting that butyrylcholinesterase is present in key brain areas and may influence the maturation of plaques in Alzheimer's disease. These accumulating data suggest that butyrylcholinesterase contributes to disease progression in people with dementia, which may be particularly important in individuals with more severe dementia as butyrylcholinesterase activity increases with disease development. It is a priority for future clinical trials to determine whether agents which inhibit butyrylcholinesterase and acetylcholinesterase have a greater clinical efficacy.

(123I)FP-CIT SPECT in suspected dementia with Lewy bodies: a longitudinal case study

OBJECTIVES

Little is known regarding the 'false-negative' or 'false-positive' striatal dopamine transporter binding on SPECT for the diagnosis of dementia with Lewy bodies (DLB). We explored the clinical course in patients fulfilling the criteria for clinical DLB with a normal ((123)I)FP-CIT SPECT (ie, SPECT scan negative, clinical features positive (S-CF+)) and patients not fulfilling DLB criteria with an abnormal scan (S+CF-).

DESIGN

Longitudinal case study over 2-5 years.

SETTING

Consecutive referrals of patients with mild dementia to dementia clinics in western Norway.

PARTICIPANTS

50 patients (27 men and 23 women; mean age at baseline of 74 (range 52-88)) with ((123)I)FP-CIT SPECT images underwent cluster analysis: 20/50 patients allocated to a 'DLB' and 8 to a 'non-DLB' cluster were included.

OUTCOME MEASURES

Scores on standardised clinical rating scales for hallucinations, parkinsonism, fluctuations, rapid eye movement (REM) sleep behaviour disorder and visually rated ((123)I)FP-CIT SPECT.

RESULTS

During the follow-up period, in the S+CF- group (n=7), frequency and severity of DLB symptoms tended to increase, particularly parkinsonism (7/7) and cognitive fluctuations (7/7), while severity of visual hallucinations and REM sleep behaviour disorder remained stable. The S-CF+ (n=3) fulfilled the operationalised criteria for probable DLB both at baseline and at the end of the follow-up.

CONCLUSIONS

The findings suggest that systematic visual analyses of ((123)I)FP-CIT SPECT can detect people with DLB prior to the development of the full clinical syndrome. In addition, the study indicates that some patients fulfilling clinical criteria for probable DLB have a normal scan, and further studies are required to characterise these patients better.

Antipsychotic medication is associated with selective alterations in ventricular cerebrospinal fluid Aβ 40 and tau in patients with intractable unipolar depression

OBJECTIVE

Alterations in plasma and in lumbar cerebrospinal fluid amyloid-B peptide (Aβ) levels have been reported in Alzheimer's disease. Studies have also suggested similar changes in depressed patients. No information is available on the impact of psychotropic drugs on this in patients with depression. We therefore quantified Aβ in ventricular cerebrospinal fluid (CSF) in a population of patients with treatment-resistant depression, with and without antipsychotic medication.

METHOD

A cross-sectional study of 32 patients undergoing subcaudate tractotomy for major (unipolar) depressive disorder. Ventricular CSF concentrations of Aβ peptide 1-40 and 1-42, also p-tau and total tau were determined by Western blotting or enzyme-linked immunosorbent assay.

RESULTS

Patients taking antipsychotic medication in the 2 weeks prior to surgery demonstrated significantly higher levels of Aβ 1-40 (mean ± SD: 727.3 ± 382.3 vs. 440.9 ± 337.2 pg/ml; p = 0.032, Student's t-test) but unaltered Aβ 1-42 (mean 72.1 ± 67.5 vs. 60.0 ± 56.7 pg/ml; p = 0.587) compared to a matched sample not treated with antipsychotic drugs. The same group demonstrated elevated total tau (mean 945.0 ± 422.2 vs. 534.3 ± 388.3 pg/ml; p = 0.010) but not p-tau (mean 98.6 ± 71.5 vs. 88.1 ± 70.5 pg/ml; p = 0.694). No similar effect was found with lithium, antidepressants, carbamazepine or benzodiazepines.

CONCLUSIONS

This preliminary study suggests antipsychotic drugs, widely used in patients with severe depression across all age ranges, may be associated with alteration of Aβ 1-40 and total tau, indices strongly linked with progressive organic brain disease. Further confirmatory work is needed.

Genetic associations of autopsy-confirmed vascular dementia subtypes

BACKGROUND/AIMS

Genetic risk factors have not been clearly established for vascular dementias (VaD) related to stroke and cerebrovascular disease.

METHODS

Samples were genotyped for APOE, MTHFR and ICAM. Aβ levels and choline acetyltransferase (ChAT) activities were assayed in controls and individuals with VaD.

RESULTS

Associations were found between the APOE-ε4 allele and mixed dementia, infarct/stroke dementia and subcortical ischemic vascular dementia (SIVD), and higher Aβ1-42 levels and decreased ChAT activity. MTHFR was more associated with SIVD, mixed dementia, and lower ChAT activity.

CONCLUSIONS

The study demonstrates important differences in the genetic associations of VaD and begins to clarify the genetic basis of key pathological substrates.

An Intron 7 Polymorphism in APP Affects the Age of Onset of Dementia in Down Syndrome

People with Down syndrome (DS) develop Alzheimer's disease (AD) with an early age of onset. A tetranucleotide repeat, attt(5-8), in intron 7 of the amyloid precursor protein has been associated with the age of onset of AD in DS in a preliminary study. The authors examine the impact of this polymorphism in a larger cohort of individuals with DS. Adults with DS were genotyped for attt(5-8) and APOE. The results were analysed with respect to the age of onset of dementia. The presence of three copies of the six-repeat allele resulted in onset of dementia seven years earlier than in the presence of other genotypes. Further study is essential to elucidate the mechanism by which this polymorphism functions, with an exciting opportunity to identify novel treatment targets relevant for people with DS and AD.

Vesicular glutamate transporter and cognition in stroke: a case-control autopsy study

OBJECTIVES

Vascular dementia (VaD) accounts for approximately 15%-20% of all dementias, but the relationship of progressive cognitive impairment to neurochemical changes is poorly understood. We have therefore investigated glutamatergic synaptic markers in VaD.

METHODS

We used homogenates prepared from gray matter from 2 neocortical regions (Brodmann area [BA] 9 and BA 20) and Western blotting to determine the concentrations of key components of the glutamatergic neurotransmitter system, vesicular glutamate transporter 1 (VGLUT1) and excitatory amino acid transporter EAAT2 (GLT-1), and the ubiquitous synaptic protein, synaptophysin, in 73 individuals-48 patients with cerebrovascular disease with and without dementia, 10 patients with AD, and 15 controls-in a case-control design.

RESULTS

VGLUT1 concentrations in BA 20 and BA 9 were correlated with CAMCOG total (Rs 0.525, p = 0.018, n = 20; Rs 0.560, p = 0.002, n = 27) and CAMCOG memory scores (Rs 0.616, p = 0.004, n = 20; Rs 0.675, p = 0.000, n = 27). VGLUT1 concentration in BA 9 differed between the different dementia groups and the stroke no dementia group (1-way analysis of variance F = 6.69, p = 0.001 and Bonferroni p < 0.01 in each case), with subjects with stroke who did not develop dementia exhibiting the highest mean value for VGLUT1.

CONCLUSIONS

These data suggest that loss of glutamatergic synapses is a feature of VaD and Alzheimer disease but the preservation of synapses, in particular glutamatergic synapses, in the frontal cortex against the temporal cortex plays a role in sustaining cognition and protecting against dementia following a stroke.

NOS3 gene rs1799983 polymorphism and incident dementia in elderly stroke survivors

Stroke is a major risk factor for the development of dementia in the elderly. It is unclear which genes influence risk of delayed dementia after stroke. We tested a single nucleotide polymorphism (SNP) in endothelial nitric oxide synthase (NOS3) gene at codon 298 (single-nucleotide polymorphism rs1799983; p.Asp298Glu) in a cohort of 355 older (>75 years) stroke survivors, who had detailed cognitive assessments from 3 months poststroke, i.e., baseline when the patients were free of dementia and subsequently at annual intervals. Of these, 253 participants were genotyped for polymorphisms in NOS3 and apolipoprotein E (APOE). Our analysis showed that homozygosity for NOS3 TT rather than the GT or GG genotype was a significant factor in the development of dementia. The presence of TT genotype increased risk of incident dementia compared with GG genotype; hazard ratio, 3.14 (95% confidence interval, 1.64-5.99; p = 0.001). We hypothesize that this may be mediated by reduction of nitric oxide production and cerebral perfusion. Our findings, if replicated widely, have implications for treatments to ameliorate cognitive decline in stroke survivors.

Choline acetyltransferase activity in vascular dementia and stroke

BACKGROUND/AIM

Alterations in cholinergic activity have not been systematically studied in types of cerebrovascular disease. We examined cholinergic function at postmortem, focussing on stroke and vascular dementia (VaD).

METHODS

Post-mortem brain tissue was studied from 61 patients with stroke or VaD (13 infarct dementia; 8 stroke/no dementia; 11 sub-cortical ischaemic VaD, SIVD; 29 VaD and concurrent Alzheimer's disease, AD), 12 patients with AD and 23 controls. Choline acetyltransferase (ChAT) was measured in Brodmann areas (BA) 9 and 20/21.

RESULTS

There were significant reductions in ChAT activity in patients with VaD and concurrent AD compared to age-matched controls (BA9: t = 2.7, p = 0.009; BA20/21: t = 4.67, p = 0.000). In patients with infarct dementia, there was a significant 27% increase in ChAT activity in BA9 (t = 2.1, p = 0.047), but not in BA20/21 (t = 1.67, p = 0.106), compared to the age-matched control group. There was no relationship between ChAT activity and cognition in the VaD patients.

CONCLUSIONS

Loss of cholinergic function is only evident in VaD patients with concurrent AD. A novel increase in cholinergic activity was identified in patients with infarct dementia, which may create important new treatment opportunities.

Management of agitation and aggression associated with Alzheimer disease

Agitation and aggression are frequently occurring and distressing behavioral and psychological symptoms of dementia (BPSD). These symptoms are disturbing for individuals with Alzheimer disease, commonly confer risk to the patient and others, and present a major management challenge for clinicians. The most widely prescribed pharmacological treatments for these symptoms-atypical antipsychotics-have a modest but significant beneficial effect in the short-term treatment (over 6-12 weeks) of aggression but limited benefits in longer term therapy. Benefits are less well established for other symptoms of agitation. In addition, concerns are growing over the potential for serious adverse outcomes with these treatments, including stroke and death. A detailed consideration of other pharmacological and nonpharmacological approaches to agitation and aggression in patients with Alzheimer disease is, therefore, imperative. This article reviews the increasing evidence in support of psychological interventions or alternative therapies (such as aromatherapy) as a first-line management strategy for agitation, as well as the potential pharmacological alternatives to atypical antipsychotics-preliminary evidence for memantine, carbamazepine, and citalopram is encouraging.

Incidence and prediction of falls in dementia: a prospective study in older people

Background

Falls are a major cause of morbidity and mortality in dementia, but there have been no prospective studies of risk factors for falling specific to this patient population, and no successful falls intervention/prevention trials. This prospective study aimed to identify modifiable risk factors for falling in older people with mild to moderate dementia.

Methods and Findings

179 participants aged over 65 years were recruited from outpatient clinics in the UK (38 Alzheimer's disease (AD), 32 Vascular dementia (VAD), 30 Dementia with Lewy bodies (DLB), 40 Parkinson's disease with dementia (PDD), 39 healthy controls). A multifactorial assessment of baseline risk factors was performed and fall diaries were completed prospectively for 12 months. Dementia participants experienced nearly 8 times more incident falls (9118/1000 person-years) than controls (1023/1000 person-years; incidence density ratio: 7.58, 3.11–18.5). In dementia, significant univariate predictors of sustaining at least one fall included diagnosis of Lewy body disorder (proportional hazard ratio (HR) adjusted for age and sex: 3.33, 2.11–5.26), and history of falls in the preceding 12 months (HR: 2.52, 1.52–4.17). In multivariate analyses, significant potentially modifiable predictors were symptomatic orthostatic hypotension (HR: 2.13, 1.19–3.80), autonomic symptom score (HR per point 0–36: 1.055, 1.012–1.099), and Cornell depression score (HR per point 0–40: 1.053, 1.01–1.099). Higher levels of physical activity were protective (HR per point 0–9: 0.827, 0.716–0.956).

Conclusions

The management of symptomatic orthostatic hypotension, autonomic symptoms and depression, and the encouragement of physical activity may provide the core elements for the most fruitful strategy to reduce falls in people with dementia. Randomised controlled trials to assess such a strategy are a priority.

Increased binding to 5-HT1A and 5-HT2A receptors is associated with large vessel infarction and relative preservation of cognition

Vascular dementia accounts for approximately 15-20% of all dementias. In addition, a significant subset of people with Alzheimer's disease have concurrent cerebrovascular disease. Vascular dementia is caused by different cerebrovascular morphological abnormalities including large artery territory infarction (multi-infarct vascular dementia) and sub-cortical ischaemic vascular dementia. Despite this distinction, there is a lack of studies examining the neurochemistry of individual vascular dementia subtypes. Serotonin is believed to play an important role in cognition, and serotonin receptors may provide a novel target for future anti-dementia therapeutics. This study aimed to determine levels of two serotonin receptors in subtypes of vascular dementia and relate any changes to cognition. We have determined, using saturation radioligand binding, the binding parameters (affinity and maximal binding) of ((3)H)-WAY 100635 binding to 5-HT(1A) receptors and ((3)H)-ketanserin binding to 5-HT(2A) receptors in post-mortem tissue from the frontal and temporal cortices of patients with either multi-infarct vascular dementia, sub-cortical ischaemic vascular dementia, mixed Alzheimer's disease/vascular dementia or stroke no dementia (SND). 5-HT(1A) and 5-HT(2A) receptor binding was significantly increased in the temporal cortex of patients with either multi-infarct vascular dementia or SND, compared to age-matched controls. 5-HT(1A) receptor maximal binding in the temporal cortex was also positively correlated with cognition as determined by Mini-Mental State Examination (MMSE) and Cambridge Assessment of Mental Health for the Elderly scores (CAMCOG). These results reveal an important distinction between the neurochemistry of multi-infarct vascular dementia/SND and sub-cortical ischaemic vascular dementia, suggesting that pharmacological manipulation of serotonin offers the possibility to develop novel therapies for stroke and multi-infarct vascular dementia patients. The results also highlight the importance of the cortical 5-HT(1A) receptor in mediating cognition.

Cortical serotonin 1A receptor levels are associated with depression in patients with dementia with Lewy bodies and Parkinson's disease dementia

BACKGROUND

Serotonin 1A receptors (5-HT(1A)) have not been studied in dementia with Lewy bodies (DLB) or Parkinson's disease dementia (PDD) patients with depression.

AIM

To examine 5-HT(1A) in DLB and PDD postmortem in relation to depression.

METHODS

[(3)H]8-hydroxy-2-dipropylaminotetralin binding to 5-HT(1A) was determined in temporal cortex (Brodmann areas, BA20 and BA36) from 10 DLB patients, 17 PDD patients and 9 controls.

RESULTS

5-HT(1A) density was significantly higher in BA36 in combined DLB/PDD patients with depression, but was unaltered in BA20.

CONCLUSION

Higher BA36 5-HT(1A) density in PDD and DLB patients than in control is dependent on whether the patient had experienced depression during life, not DLB/PDD diagnosis. A 5-HT(1A) antagonist adjuvant may improve treatment of depression in dementia.

The extended tau haplotype and the age of onset of dementia in Down syndrome

BACKGROUND/AIMS

Most people with Down syndrome (DS) develop Alzheimer's disease (AD). The extended tau haplotype has been linked to AD. In this study, we examined the haplotype's effect on the age of onset of AD in DS.

METHODS

People with DS were assessed for dementia. Genotyping was performed for the extended tau haplotype, APOE and a polymorphism in APP, attt(5-8).

RESULTS

Haplotype frequencies vary between those developing AD before 45 and those developing dementia after this age (p = 0.03). H1/H2 individuals are more likely to develop dementia before 45 than H1/H1 individuals (OR = 3, 95% CI = 1.01-8.91).

CONCLUSION

Even in a condition driven by excess amyloid pathology, factors affecting tau are also important and should be considered as potential treatment targets.

Inflammatory mediators in the frontal lobe of patients with mixed and vascular dementia

Vascular dementia (VaD) accounts for about 20% of all dementias, and vascular risk is a key factor in more than 40% of people with Alzheimer's disease (AD). Little is known about inflammatory processes in the brains of these individuals. We have examined inflammatory mediators (interleukin (IL)-1beta, IL-1alpha, IL-6 and tumour necrosis factor alpha) and chemokines (macrophage inflammatory protein 1, monocyte chemo-attractant protein (MCP)-1 and granulocyte macrophage colony-stimulating factor) in brain homogenates from grey and white matter of the frontal cortex (Brodmann area 9) from patients with VaD (n = 11), those with concurrent VaD and AD (mixed dementia; n = 8) and from age-matched controls (n = 13) using ELISA assays. We found a dramatic reduction of MCP-1 levels in the grey matter in VaD and mixed dementia in comparison to controls (55 and 66%, respectively). IL-6 decreases were also observed in the grey matter of VaD and mixed dementia (72 and 71%, respectively), with a more modest decrease (30%) in the white matter of patients with VaD or mixed dementia. In the first study to examine the status of inflammatory mediators in a brain region severely affected by white-matter lesions, our findings highlight - in contrast to previous reports in AD - that patients at the later stage of VaD or mixed dementia have a significantly attenuated neuro-inflammatory response.

An extract of Salvia (sage) with anticholinesterase properties improves memory and attention in healthy older volunteers

RATIONALE

Species of Salvia (sage) have a long-standing reputation in European medical herbalism, including for memory enhancement. In recent controlled trials, administration of sage extracts with established cholinergic properties improved cognitive function in young adults.

OBJECTIVES

This randomised, placebo-controlled, double-blind, balanced, five-period crossover study investigated the acute effects on cognitive performance of a standardised extract of Salvia officinalis in older adults.

MATERIALS AND METHODS

Twenty volunteers (>65 years of age, mean = 72.95) received four active doses of extract (167, 333, 666 and 1332 mg) and a placebo with a 7-day wash-out period between visits. Assessment involved completion of the Cognitive Drug Research computerised assessment battery. On study days, treatments were administered immediately following a baseline assessment with further assessment at 1, 2.5, 4 and 6 h post treatment.

RESULTS

Compared with the placebo condition (which exhibited the characteristic performance decline over the day), the 333-mg dose was associated with significant enhancement of secondary memory performance at all testing times. The same measure benefited to a lesser extent from other doses. There also were significant improvements to accuracy of attention following the 333-mg dose. In vitro analysis confirmed cholinesterase inhibiting properties for the extract.

CONCLUSIONS

The overall pattern of results is consistent with a dose-related benefit to processes involved in efficient stimulus processing and/or memory consolidation rather than retrieval or working memory efficiency. These findings extend those of the memory-enhancing effects of Salvia extracts in younger populations and warrant further investigation in larger series, in other populations and with different dosing regimes.

Memantine for agitation/aggression and psychosis in moderately severe to severe Alzheimer's disease: a pooled analysis of 3 studies

OBJECTIVE

Long-standing evidence indicates that Alzheimer's disease patients with behavioral symptoms have a worse prognosis and a more rapid disease progression. The current retrospective analysis evaluated the efficacy and safety of memantine in a subpopulation of patients with Alzheimer's disease exhibiting behavioral symptoms of agitation/aggression or psychosis at baseline.

METHOD

A pooled analysis was conducted in people with agitation/aggression or psychosis from 3 large 6-month, randomized studies in moderately severe to severe Alzheimer's disease. The effect of memantine and placebo on these specific symptoms was evaluated using the Neuropsychiatric Inventory (NPI) subitem cluster of agitation and psychosis. Outcomes on global, cognitive, and functional measures were also analyzed.

RESULTS

Sixty percent of the total patient group had baseline symptoms of agitation/aggression, delusions, or hallucinations on the NPI. At both 12 and 24/28 weeks, there was a significant treatment advantage for memantine over placebo for the proportion of patients showing improvement on the defined neuropsychiatric symptom cluster (55.6% vs. 44.4% at week 12, p = .008; 58.0% vs. 44.8% at week 24/28, p = .002) and specifically for the treatment of agitation/aggression (55.3% vs. 43.1% at week 12, p = .011; 61.0% vs. 45.0% at week 24/28, p < .001). Placebo-treated patients in this population demonstrated an accelerated disease progression for global (Clinician's Interview-Based Impression of Change Plus Caregiver Input), cognitive (Severe Impairment Battery), and functional (Alzheimer Disease Cooperative Study Activities of Daily Living Inventory 19-item scale) outcomes, but memantine conferred statistically significant benefit for all measures. Tolerability in this population remained good, and fewer memantine-treated patients than placebo-treated patients withdrew due to adverse events.

CONCLUSIONS

This post hoc analysis provides important evidence from placebo-controlled trials that memantine may be a safe and effective treatment in Alzheimer's disease patients with agitation/aggression or psychosis, who are otherwise prone to rapid progression. Memantine treatment provided benefits in cognitive, functional, and global outcomes in these patients and for their agitation/aggression.