Memantine for dementia

Memantine improves cognition and reduces Alzheimer's-like neuropathology in transgenic mice

Memantine is an N-methyl-d-aspartate receptor antagonist that is approved for the treatment of moderate to severe Alzheimer's disease (AD). In this study, three groups of triple-transgenic (3xTg-AD) mice with differing levels of AD-like pathology (6, 9, and 15 months of age) were treated for 3 months with doses of memantine equivalent to those used in humans. After the treatment, memantine-treated mice had restored cognition and significantly reduced the levels of insoluble amyloid-beta (Abeta), Abeta dodecamers (Abeta*56), prefibrillar soluble oligomers, and fibrillar oligomers. The effects on pathology were stronger in older, more impaired animals. Memantine treatment also was associated with a decline in the levels of total tau and hyperphosphorylated tau. Finally, memantine pre-incubation prevented Abeta-induced inhibition of long-term potentiation in hippocampal slices of cognitively normal mice. These results suggest that the effects of memantine treatment on AD brain include disease modification and prevention of synaptic dysfunction.

Packages of care for dementia in low- and middle-income countries

In the fifth in a series of six articles on packages of care for mental disorders in low- and middle-income countries, Martin Prince and colleagues discuss the treatment of dementia.

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.

Novel regimens and delivery systems in the pharmacological treatment of Alzheimer's disease

The mainstay of current management of patients with Alzheimer's disease involves drugs that provide symptomatic therapy. Research approaches for future therapy of Alzheimer's disease are focusing on disease modifying and/or preventive approaches. Two classes of medications have been approved by the US FDA for the treatment of Alzheimer's disease: the cholinesterase inhibitors (tacrine, donepezil, rivastigmine, galantamine), mostly for mild to moderate Alzheimer's disease, and the noncompetitive NMDA receptor antagonist memantine for the moderate to severe stages of Alzheimer's disease. Management of comorbid medical problems can be more complex in patients with dementia than in those without dementia. Unfortunately, medication adherence in Alzheimer's disease is low and good adherence is essential for attempting to slow disease progression and improve or stabilize quality of life. Simplifying treatment regimens and providing more caregiver- and patient-friendly modes of administration that fit in better with daily routines can ease caregiver stress which, in turn, may have a favourable impact on the patient's condition. To overcome problems of medication adherence in the elderly, simple, user-friendly dosage regimens should be prescribed for all medications; thus the need for novel regimens and delivery systems in the pharmacological treatment of Alzheimer's disease, such as once-daily donepezil, memantine and galantamine, and transdermal rivastigmine.

Aggression in persons with dementia: use of nursing theory to guide clinical practice

With approximately four million people in the United States today diagnosed with dementia, one of the most devastating problems faced by caregivers and patients is dealing with aggressive behavior. Aggression occurs in half of persons diagnosed with dementia and is associated with more rapid cognitive decline, increased risk of abuse, and caregiver burden. This paper uses the Need-driven Dementia-compromised Behavior (NDB) model to explain aggression and discusses therapeutic approaches to care that combines non-pharmacological and pharmacological interventions targeting both the management of aggression crisis and preventing its future recurrence. A clinical algorithm guided by the NBD model is provided for practitioners.

Therapy for Alzheimer's Disease: How Effective are Current Treatments?

Available symptomatic therapies for the treatment of Alzheimer's disease (AD) have been based on known neurotransmitter dysfunctions associated with the illness. The second-generation cholinesterase inhibitors and the N-methyl D-aspartate receptor antagonist memantine have been widely prescribed and studied. Meta-analyses of these therapies were reviewed, focusing on effectiveness and tolerability. Although many of the meta-analyses demonstrate statistically significant improvements, some question if these benefits are sufficient to justify their current widespread and protracted use. This has spurred the development of new disease-modifying therapies that aim to have a greater impact on this debilitating illness.

Huperzine A for vascular dementia

BACKGROUND

Huperzine A, a form of herbal medicine, has been considered as an alternative treatment for vascular dementia (VaD) in China.

OBJECTIVES

To assess the efficacy and safety of Huperzine A in patients with vascular dementia.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG) was searched on 7 July 2008 using the terms: huperzi* OR ayapin OR scoparon*. The CDCIG Specialized Register contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many trials databases and grey literature sources. The review authors searched the following databases in August 2008 using the terms 'Huperzine A', 'Shishanjianjia', 'Haboyin' and 'Shuangyiping': The Chinese Biomedical Database (CBM) (1977 to August 2008); Chinese Science and Technique Journals Database (VIP) (1989 to August 2008); China National Knowledge Infrastructure (CNKI) (1979 to August 2008); The Chinese Clinical Trials Register (ChiCTR, August 2008); Google (August 2008). In addition, the review authors searched reference lists, relevant clinical trials and contacted researchers in an effort to identify further published and unpublished studies.

SELECTION CRITERIA

Randomized controlled trials comparing Huperzine A with placebo in patients with vascular dementia were considered eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data.

MAIN RESULTS

Only one small trial, involving 14 participants, was included. No significant beneficial effect of Huperzine A on the improvement of cognitive function measured by MMSE for VaD (WMD 2.40; 95% CI -4.78 to 9.58) was observed. No death from all causes at the end of treatment were reported. At present, other outcome measures were not available in any of the trials. Although no statistically significant differences were found between the Huperzine A-treated and control groups, the confidence intervals for the treatment effect estimates were wide and included both clinically significant benefits and clinically significant harms.

AUTHORS' CONCLUSIONS

There is no [convincing] evidence that Huperzine A is of value in vascular dementia based on one small trial. It deserves further research.

Pharmacological Treatment of Alzheimer's Disease: Is it Progressing Adequately?

INTRODUCTION

Between 1993 and 2000 four acetylcholinesterase inhibitors were marketed as a symptomatic treatment for Alzheimer's disease (AD), as well as memantine in 2003. Current research is focused on finding drugs that favorably modify the course of the disease. However, their entrance into the market does not seem to be imminent.

RESEARCH DEVELOPMENT

The aim of AD research is to find substances that inhibit certain elements of the AD pathogenic chain (beta- and gamma-secretase inhibitors, alpha-secretase stimulants, beta-amyloid aggregability reducers or disaggregation and elimination inductors, as well as tau-hyperphosphorylation, glutamate excitotoxicity, oxidative stress and mitochondrial damage reducers, among other action mechanisms). Demonstrating a disease's retarding effect demands longer trials than those necessary to ascertain symptomatic improvement. Besides, a high number of patients (thousands of them) is necessary, all of which turns out to be difficult and costly. Furthermore, it would be necessary to count on diagnosis and progression markers in the disease's pre-clinical stage, markers for specific phenotypes, as well as high-selectivity molecules acting only where necessary. In order to compensate these difficulties, drugs acting on several defects of the pathogenic chain or showing both symptomatic and neuroprotective action simultaneously are being researched.

CONCLUSIONS

There are multiple molecules used in research to modify AD progression. Although it turns out to be difficult to obtain drugs with sufficient efficacy so that their marketing is approved, if they were achieved they would lead to a reduction of AD prevalence.

Treatment of dementia and cognitive impairment: what can we learn from the Cochrane Library

BACKGROUND

Systematic reviews of health care interventions in a single database have great practical value.

METHODS

We analyze the dementia related information in the Cochrane Library.

RESULTS

In 2008 the Cochrane Library has over 5300 systematic reviews, and in the latest - 2008/3 - issue over 100 reviews have the term "dementia" in their title, abstract or keywords. The Cochrane Dementia and Cognitive Improvement Group has a major role in preparing systematic reviews of randomized clinical trials in the field of dementia. Pharmacological as well as non-pharmacological interventions are analyzed. The reviews are prepared by strict methodology and have uniformed, organized structure. Cochrane reviews or at least their abstracts are available free of charge at www.cochrane.org. About an intervention a review may find evidence of benefit, evidence of harm, or evidence of no effect. For several interventions there is not enough evidence of effect - due to lack of information or if the studies are not conclusive, further research is recommended. In addition to systematic reviews the Cochrane Library includes a large database of bibliographic data of randomized controlled trials, technology assessments and economic evaluations.

CONCLUSIONS

The use of this source of information is strongly recommended for all who are involved in patient care or health care policy.

Ginkgo biloba extract EGb 761(R), donepezil or both combined in the treatment of Alzheimer's disease with neuropsychiatric features: a randomised, double-blind, exploratory trial

OBJECTIVE

This randomised, double-blind exploratory trial was undertaken to compare treatment effects and tolerability of EGb 761(R), donepezil and combined treatment in patients with AD and neuropsychiatric features.

METHOD

We enrolled 96 outpatients, aged 50 years or above, who met the NINCDS/ADRDA criteria for probable AD, scored below 36 on the TE4D, a screening test for dementia, below 6 on the Clock-Drawing Test (CDT) and between 9 and 23 on the SKT, a cross-culturally validated cognitive test battery. They scored at least five on the 12-item Neuropsychiatric Inventory (NPI). EGb 761(R) (240 mg per day), donepezil (initially 5 mg, after 4 weeks 10 mg per day) or EGb 761(R) and donepezil combined (same doses) were administered for 22 weeks.

RESULTS

Changes from baseline to week 22 and response rates were similar for all three treatment groups with respect to all outcome measures (SKT, NPI, total score and activities-of-daily-living sub-score of the Gottfries-Bråne-Steen Scale, Hamilton Rating Scale for Depression, CDT and Verbal Fluency Test). An apparent tendency in favour of combination treatment warrants further scrutiny. Compared to donepezil mono-therapy, the adverse event rate was lower under EGb 761(R) treatment and even under the combination treatment.

CONCLUSION

These exploratory findings helped to develop three hypotheses that will have to be proven in further studies: (1) there is no significant difference in the efficiency between EGb 761(R) and donepezil, (2) a combination therapy will be superior to a mono-therapy with one of both substances and (3) there will be less side effects under a combination therapy than under mono-therapy with donepezil.

Memantine for dementia in people with Down syndrome

BACKGROUND

Alzheimer's dementia (AD) is the most common form of dementia in people with Down Syndrome (DS). There is an understanding that an increase in L-glutamate contributes to the pathogenesis of cerebral ischemias and AD. Memantine acts as an antagonist of N-methyl-D-aspartate (NMDA) type receptors, which is thought to reduce abnormal activation of glutamate neurotransmission. It binds with a low affinity to the NMDA receptor and so should not prevent learning and the formation of memory. Memantine can improve cognitive function and slow the decline of AD in the general population over time, and is the subject of this review. It is important to note that people with DS tend to present with AD at a much younger age than the normal population as well as having subtle differences in physiology (e.g. metabolism and heart rate) and may therefore have different requirements from the general population.

OBJECTIVES

To determine the effectiveness and safety of memantine for people with DS who develop AD.

SEARCH STRATEGY

CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, BIOSIS, SCI, SSCI and the NRR were searched up to October 2008. We contacted the manufacturers of memantine, as well as experts in the field, to ask about reports of unpublished or ongoing trials.

SELECTION CRITERIA

Randomised controlled trials of participants with DS and AD in which treatment with memantine was administered compared with a placebo group.

DATA COLLECTION AND ANALYSIS

No study was identified which met the inclusion criteria for this review.

MAIN RESULTS

No study was identified which met inclusion criteria for this review, however there is an on-going randomised controlled study being conducted in the UK and data are expected in 2009.

AUTHORS' CONCLUSIONS

As there are no included trials, recommendations cannot be made about memantine for AD in DS. Well-designed, adequately powered studies are required.

Searching for unpublished trials in Cochrane reviews may not be worth the effort

OBJECTIVE

To assess the value of searching for unpublished data by exploring the extent to which Cochrane reviews include unpublished data and by evaluating the quality of unpublished trials.

STUDY DESIGN AND SETTING

We screened all 2,462 completed Cochrane reviews published since 2000 in the Cochrane Database of Systematic Reviews Issue 3, 2006. In a random sample (n=61) of 292 reviews, including unpublished trials, we studied all 116 references.

RESULTS

Unpublished trials make up 8.8% of all included trials in our sample. Thirty-eight percent of the "unpublished" trials have in fact been published. Allocation concealment was "unclear" or not adequate in 54.3% and 61.3% reported blinding. In 47.2% reported withdrawal rates were >20%. Trials that were eventually published had larger mean population sizes (P-value, 0.02). Of the reported sponsors, 87.3% were drug companies. Methodological quality and publication bias are mentioned in half of the reviews and explored in a third. Quality ratings did not have consequences for pooling, because 82.8% was included in the forest plots.

CONCLUSIONS

A minority of Cochrane reviews include "unpublished trials" and many of these are eventually published. Truly unpublished studies have poor or unclear methodological quality. Therefore, it may be better to invest in regular updating of reviews, rather than in extensive searching for unpublished data.

RO4938581, a novel cognitive enhancer acting at GABAA alpha5 subunit-containing receptors

RATIONALE

GABAA alpha5 subunit-containing receptors are primarily expressed in the hippocampus and their role in learning and memory has been demonstrated recently by both genetic and pharmacological approaches.

OBJECTIVES

The objective of the study is to evaluate the cognitive effects of a novel GABAA alpha5 receptor inverse agonist, RO4938581 in rats and monkeys.

MATERIALS AND METHODS

The in vitro profile was determined using radioligand binding and electrophysiological assays for the GABAA alpha1, alpha2, alpha3, and alpha5 receptors. Long-term potentiation (LTP) was performed in mouse hippocampal slices. Cognitive effects were assessed in rats in the delayed match to position (DMTP) task and the Morris water maze. In monkeys, the object retrieval task was used. Pro-convulsant and anxiogenic potentials were evaluated in mice and rats. In vivo receptor occupancy was determined using [3H]-RO0154513.

RESULTS

RO4938581 is a potent inverse agonist at the GABAA alpha5 receptor, with both binding and functional selectivity, enhancing hippocampal LTP. RO4938581 reversed scopolamine-induced working memory impairment in the DMTP task (0.3-1 mg/kg p.o.) and diazepam-induced spatial learning impairment (1-10 mg/kg p.o.). RO4938581 improved executive function in monkeys (3-10 mg/kg p.o.). Importantly, RO4938581 showed no anxiogenic and pro-convulsive potential. RO4938581 dose-dependently bound to GABAA alpha5 receptors and approximately 30% receptor occupancy was sufficient to produce enhanced cognition in the rat.

CONCLUSIONS

The data further support the potential of GABAA alpha5 receptors as a target for cognition-enhancing drugs. The dual binding and functional selectivity offers an ideal profile for cognition-enhancing effects without the unwanted side effects associated with activity at other GABAA receptor subtypes.

Update on the use of memantine in Alzheimer's disease

Memantine is a low to moderate affinity N-methyl-D-aspartate receptor (NMDAR) antagonist. The effects of memantine in Alzheimer's disease (AD) have been studied in 7 randomized controlled trials in many post-hoc analyses. Three out of four RCTs in patients with moderate to severe AD (Mini Mental State Examination [MMSE] <14) showed a statistically significant but clinically small positive effect of memantine on cognition, global functioning, activities of daily living (ADL) and neuropsychiatric symptoms. No effects on these outcome measures could be found in the three RCTs studying patients with mild to moderate AD (MMSE 14-24). Two of these studies evaluated the effect of addition of memantine to donepezil. Only the study in patients with mild to moderate AD showed a positive effect of addition of memantine on cognition, ADL, global functioning and neuropsychiatric functioning. Cost-effectiveness of memantine therapy remains controversial. Post-hoc analyses and observational studies suggest some effects on agitation/aggression, delusions or hallucinations. Side effects of memantine are usually mild and seem to be comparable with placebo. In this review, an oversight of pharmacodynamics and pharmacokinetics of memantine is presented. Also, published data concerning efficacy and safety in patients with AD are presented.

Riluzole in the treatment of mood and anxiety disorders

Recent advances implicate amino acid neurotransmission in the pathophysiology and treatment of mood and anxiety disorders. Riluzole, which is approved and marketed for the treatment of amyotrophic lateral sclerosis, is thought to be neuroprotective through its modulation of glutamatergic neurotransmission. Riluzole has multiple molecular actions in vitro; the two that have been documented to occur at physiologically realistic drug concentrations and are therefore most likely to be clinically relevant are inhibition of certain voltage-gated sodium channels, which can lead to reduced neurotransmitter release, and enhanced astrocytic uptake of extracellular glutamate.Although double-blind, placebo-controlled trials are lacking, several open-label trials have suggested that riluzole, either as monotherapy or as augmentation of standard therapy, reduces symptoms of obsessive-compulsive disorder, unipolar and bipolar depression, and generalized anxiety disorder. In studies of psychiatrically ill patients conducted to date, the drug has been quite well tolerated; common adverse effects include nausea and sedation. Elevation of liver function tests is common and necessitates periodic monitoring, but has been without clinical consequence in studies conducted to date in psychiatric populations. Case reports suggest utility in other conditions, including trichotillomania and self-injurious behaviour associated with borderline personality disorder. Riluzole may hold promise for the treatment of several psychiatric conditions, possibly through its ability to modulate pathologically dysregulated glutamate levels, and merits further investigation.

Memantine for the treatment of Alzheimer's disease: tolerability and safety data from clinical trials

BACKGROUND

Memantine, a moderate-affinity, uncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors, is the first non-cholinergic agent approved for the treatment of Alzheimer's disease (AD), and the first medication approved in the US and Europe for the treatment of moderate to severe stages of the disease. The objective of this study was to analyse safety and tolerability data from phase III memantine trials and from the open-label extensions of those trials.

METHOD

We conducted an analysis of the pooled data for tolerability and safety from six double-blind, placebo-controlled, memantine trials with a minimum duration of 24 weeks (three trials in mild to moderate AD and three in moderate to severe AD; 20 mg/day; 2311 patients) and four open-label extensions of those trials (two in mild to moderate AD and two in moderate to severe AD; 20 mg/day, 1405 patients), for a total treatment period of up to 2 years.

RESULTS

The analysis revealed that adverse events occurring during both short- and long-term memantine treatment were minimal, and similar in type and frequency to those reported for placebo-treated patients. The most frequently reported adverse events in placebo-controlled trials included agitation (7.5% memantine vs 12.0% placebo), falls (6.8% vs 7.1%), dizziness (6.3% vs 5.7%), accidental injury (6.0% vs 7.2%), influenza-like symptoms (6.0% vs 5.8%), headache (5.2% vs 3.7%) and diarrhoea (5.0% vs 5.6%). Discontinuations due to adverse events were similar in memantine- and placebo-treated groups (8.9% vs 9.8%, respectively).

CONCLUSION

Consistent with the favourable tolerability profile of memantine observed in clinical use, this analysis of pooled safety data indicates that both short- and long-term memantine treatment of patients with AD is safe and well tolerated, with an adverse event profile similar to that of placebo.

Long-term course and effectiveness of combination therapy in Alzheimer disease

OBJECTIVE

To compare the real-world clinical effectiveness and long-term clinical trajectory in patients with Alzheimer disease (AD) treated with combination (COMBO) therapy consisting of cholinesterase-inhibitor (CI) plus memantine (MEM) versus CI alone versus no treatment with either.

METHODS

Three hundred eighty-two subjects with probable AD underwent serial clinical evaluations at a memory disorders unit. Cognition was assessed by the Information-Memory-Concentration subscale of the Blessed Dementia Scale (BDS) and function was assessed by the Weintraub Activities of Daily Living Scale (ADL) at 6-month intervals. One hundred forty-four subjects received standard care without CI or MEM (NO-RX), 122 received CI monotherapy, and 116 received COMBO therapy with CI plus MEM. Mean follow-up was 30 months (4.1 visits) and mean cumulative medication treatment time was 22.5 months. Rates of decline were analyzed using mixed-effects regression models, and Cohen's d effect sizes were calculated annually for years 1 to 4.

RESULTS

Covarying for baseline scores, age, education, and duration of illness, the COMBO group had significantly lower mean annualized rates of deterioration in BDS and ADL scores compared with the CI (P<0.001; Cohen's dBDS=0.10-0.34 and dADL=0.23-0.46 at 1 to 2 y) and NO-RX groups (P<0.001; Cohen's dBDS=0.56-0.73 and dADL=0.32-0.48 at 1 to 2 y). For the COMBO group, Cohen's d effect sizes increased with treatment duration. Similar comparisons significantly favored the CI over the NO-RX group on the BDS.

CONCLUSIONS

COMBO therapy slows cognitive and functional decline in AD compared with CI monotherapy and no treatment. These benefits had small-to-medium effect sizes that increased with time on treatment and were sustained for years.

Antagonism of glutamatergic NMDA and mGluR5 receptors decreases consumption of food in baboon model of binge-eating disorder

Excessive consumption of highly palatable foods may contribute to the development of weight gain. Therefore medications that selectively suppress eating of such foods would be useful in clinical practice. We compared the effects of the glutamatergic antagonists memantine and MTEP to dexfenfluramine in baboons given periodic access to highly palatable food and ad libitum access to a standard chow diet. Three days a week baboons received a sugar-coated candy during the first meal and standard standard-diet chow pellets were available in subsequent meals. All baboons derived a greater amount of energy from the single single-candy meal than from the standard diet across an entire day. Pre-treatment with dexfenfluramine, memantine, and MTEP produced decreases in candy consumption without altering candy-seeking behaviour. At the same time, dexfenfluramine and memantine, but not MTEP, produced a decrease in seeking and consumption of standard chow pellets. Both memantine and MTEP are promising agents for the treatment of obesity.

NMDA receptors in clinical neurology: excitatory times ahead

Since the N-methyl-D-aspartate receptor (NMDAR) subunits were cloned less than two decades ago, a substantial amount of research has been invested into understanding their physiological function in the healthy CNS. Research has also been directed at their pathological roles in various neurological diseases, including disorders resulting from acute excitotoxic insults (eg, ischaemic stroke, traumatic brain injury), diseases due to chronic neurodegeneration (eg, Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis), disorders arising from sensitisation of neurons (eg, epilepsy, neuropathic pain), and neurodevelopmental disorders associated with NMDAR hypofunction (eg, schizophrenia). Selective NMDAR antagonists have not produced positive results in clinical trials. However, there are other NMDAR-targeted therapies used in current practice that are effective for treating some neurological disorders. In this Review, we describe the evidence for the use of these therapies and provide an overview of drugs being investigated in clinical trials. We also discuss new NMDAR-targeted strategies in clinical neurology.

Alternatives to atypical antipsychotics for the management of dementia-related agitation

Numerous recent studies have challenged the widely held belief that atypical antipsychotics are safe and effective options for the treatment of behavioural problems such as agitation in patients with dementia. Accordingly, there is a need to reconsider the place of atypical antipsychotics in the treatment of patients with dementia. The present article is intended to assist clinicians with the assessment and pharmacological management of agitation in patients with dementia. We review the risk-benefit evidence for the use of atypical antipsychotics in patients with dementia-related agitation (DRA). Emerging evidence indicates that, for patients with dementia, the risks associated with atypical antipsychotics may outweigh the benefits except for patients with severe agitation who require short-term chemical restraint. We then discuss the importance of a careful assessment to rule out potentially reversible factors contributing to DRA. Finally, we summarize the evidence supporting the use of medications other than antipsychotics to treat DRA. There is wide variability in the levels of evidence supporting the use of non-antipsychotic medication for the treatment of DRA. The best evidence currently exists for cholinesterase inhibitors and serotonin-specific reuptake inhibitor antidepressants. Emerging reports suggest that numerous other medications, for example, antiepileptics, lithium, anxiolytics, analgesics, beta-adrenoceptor antagonists, cannabinoid receptor agonists and hormonal agents, may prove to be viable alternatives to antipsychotics for the treatment of severe DRA and more research is urgently needed to help assess the effectiveness of these agents. A comprehensive biopsychosocial assessment and treatment plan is likely the most effective way to manage DRA.

Present and prospective clinical therapeutic regimens for Alzheimer's disease

Alzheimer's disease (AD) is an incurable neurodegenerative disorder that produces cognitive impairments that increase in severity as the disease progresses. The clinical symptoms are related to the presence of neuritic plaques and neurofibrillary tangles in the cerebral cortex which represent the pathophysiological hallmarks of AD. The debilitating nature of the disease can result in clinical burden for the patient, emotional strain for those that care for patients with Alzheimer's, and significant financial burden to society. The goals of current treatments, such as cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonist, are to reduce the severity or slow the progression of cognitive symptoms. Although these treatments have demonstrated modest clinical benefit, they are unable to prevent, prohibit, or reverse the underlying pathophysiology of AD. Considerable progress has been made toward the development of disease-modifying treatments. Treatments currently under development mainly target the production, aggregation, and removal of existing amyloid beta-peptide aggregates which are believed to instigate the overall development of the neuropathology. Additional strategies that target tau pathology are being studied to promote neural protection against AD pathology. The current research has continued to expand our knowledge toward the development of disease modifying Alzheimer's therapies; however, no specific treatment strategy capable of demonstrating empirical efficacy and safety has yet to emerge.

Effect of dimebon on cognition, activities of daily living, behaviour, and global function in patients with mild-to-moderate Alzheimer's disease: a randomised, double-blind, placebo-controlled study

BACKGROUND

Although treatments for Alzheimer's disease sometimes improve cognition, functional ability, or behaviour compared with baseline levels, such improvements are inconsistent across studies and measures, and effects diminish over time. More effective treatments are needed. We assessed the safety, tolerability, and efficacy of dimebon in the treatment of patients with mild-to-moderate Alzheimer's disease.

METHODS

We enrolled 183 patients with mild-to-moderate Alzheimer's disease (mini-mental state examination [MMSE] scores 10-24) at 11 sites in Russia. Patients were randomly assigned by a computer-generated randomisation scheme to receive oral dimebon, 20 mg three times a day (60 mg/day [n=89]), or matched placebo (n=94). Other antidementia drugs were not allowed. The primary outcome measure assessed cognition, the difference in mean change from baseline to week 26, or last completed observation on the cognitive subscale of the Alzheimer's disease assessment scale (ADAS-cog). All patients and study personnel were blinded throughout the study. We compared dimebon with placebo with an intention-to-treat analysis, with last observation carried forward (ITT-LOCF) imputation. Analyses were repeated on the fully evaluable population, defined as all patients in the intention-to-treat population who had an ADAS-cog at week 26 and at least 80% compliance. 134 patients (68 in dimebon group, 66 in placebo group) enrolled in the 6-month blinded extension phase of the study. This trial is registered with Clinicaltrials.gov, number NCT00377715.

FINDINGS

155 (85%) patients completed the trial (78 [88%] in dimebon group, 77 [82%] in placebo group). Treatment with dimebon resulted in significant benefits in ADAS-cog compared with placebo (ITT-LOCF) at week 26 (mean drug-placebo difference -4.0 [95% CI -5.73 to -2.28]; p<0.0001). Results of the ITT-LOCF and the evaluable population analyses were much the same for all measures. Patients given dimebon were significantly improved over baseline for ADAS-cog (mean difference -1.9 [-2.92 to -0.85]; p=0.0005). Dimebon was well tolerated: dry mouth and depressed mood or depression were the most common adverse events associated with dimebon (12 [14%] patients for each symptom by week 26). The percentage of patients who had adverse events in the two groups did not differ.

INTERPRETATION

Dimebon was safe, well tolerated, and significantly improved the clinical course of patients with mild-to-moderate Alzheimer's disease.

Blocking kinetics of memantine on NR1a/2A receptors recorded in inside-out and outside-out patches from Xenopus oocytes

Previous experiments on primary cultures of hippocampal/cortical neurones revealed that the block and unblock of N-Methyl-D-Aspartate (NMDA) receptor channels by memantine showed double exponential kinetics and that the offset kinetics following a voltage-step were much faster than following a concentration jump. There are, however, two major problems when using such cultured primary neurones for these experiments (1) the almost certain expression of heterogeneous NMDA receptor subunits which could underlie double exponential kinetics due to different potencies at receptor subtypes and (2) slow space- and concentration-clamp due to neuronal morphology which could mask even faster kinetics. Therefore, we performed similar experiments with Xenopus oocytes exclusively expressing one NMDA receptor type (NR1a/2A) at high levels which allowed recordings from membrane patches with large currents. The use of inside-out patches for voltage-step and outside-out patches in combination with a piezo driven fast application system largely negated potential space- and concentration-clamp problems. Block and unblock of the NMDA receptor by memantine after both voltage jump and concentration jumps showed triple exponential kinetics. The fast onset kinetics of NMDA receptor channel block following both concentration-clamp and voltage jumps from +70 to -70 mV were similar. In contrast, offset kinetics after a voltage-step from -70 to +70 mV were much faster than following a concentration jump at the holding potential of -70 mV. These results provide further support for the hypothesis that rapid relief of block via strong synaptic membrane depolarisation underlies the good therapeutic profile of memantine.

Treatment options in Alzheimer's disease: maximizing benefit, managing expectations

Alzheimer's disease (AD) is becoming an increasingly heavy burden on the society of developed countries, and physicians now face the challenge of providing efficient treatment regimens to an ever-higher number of individuals affected by the disease. Currently approved anti-AD therapies - the cholinesterase inhibitors and the N-methyl-D-aspartate receptor antagonist memantine - offer modest symptomatic relief, which can be enhanced using combination therapy with both classes of drugs. Additionally, alternative therapies such as nonsteroidal anti-inflammatory drugs, vitamin E, selegiline, Ginkgo biloba extracts, estrogens, and statins, as well as behavioral and lifestyle changes, have been explored as therapeutic options. Until a therapy is developed that can prevent or reverse the disease, the optimal goal for effective AD management is to develop a treatment regimen that will yield maximum benefits for individual patients across multiple domains, including cognition, daily functioning, and behavior, and to provide realistic expectations for patients and caregivers throughout the course of the disease. This review provides a basic overview of approved AD therapies, discusses some pharmacologic and nonpharmacologic treatment strategies that are currently being investigated, and offers suggestions for optimizing treatment to fit the needs of individual patients.

Huperzine A for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) has become a major public health problem around the world due to its increasing prevalence, long duration, caregiver burden, and high financial cost of care. The degeneration of acetylcholine-containing neurons in the basal forebrain has been implicated in the symptoms of AD. Cholinesterase inhibitors may block the degradation of acetylcholine, thus increasing the efficacy of the remaining cholinergic neurons. Huperzine A is a linearly competitive, reversible inhibitor of acetyl cholinesterase that is said to have both central and peripheral activity with the ability to protect cells against hydrogen peroxide, beta-amyloid protein (or peptide), glutamate, ischemia and staurosporine-induced cytotoxicity and apoptosis. These properties might qualify Huperzine A as a promising agent for treating dementia (including AD).

OBJECTIVES

To assess the efficacy and safety of Huperzine A for the treatment of patients with AD.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group was searched on 1 February 2006 using the search term: huperzin*. The CDCIG Specialized register contains records from all major health care databases (MEDLINE, EMBASE, PsycINFO, CINAHL, SIGLE, ISTP, INSIDE, LILACS) as well as from many trials databases and grey literature sources. In addition, the CBM and AMED databases and relevant websites were searched and some journals were hand-searched. Specialists in the field were approached for unpublished material and any publications found were searched for additional references.

SELECTION CRITERIA

All relevant randomized controlled trials (RCTs) studying the efficacy and safety of Huperzine A for AD.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers using a self-developed data extraction form and entered into RevMan 4.2.10 software. Meta-analyses were performed when more than one trial provided data on a comparable outcome on sufficiently similar patients. Random effects analyses were performed whenever heterogeneity between results appeared to be present. Standardized differences in mean outcome measures were used due to the use of different scales and periods of treatment.

MAIN RESULTS

Six trials including a total of 454 patients met our inclusion criteria. The methodological quality of most included trials was not high. It was shown that compared to placebo, Huperzine A had beneficial effects on the improvement of general cognitive function measured by MMSE (WMD 2.81; 95% CI 1.87 to 3.76; P < 0.00001) and ADAS-Cog at six weeks (WMD 1.91; 95% CI 1.27 to 2.55) and at 12 weeks (WMD 2.51; 95% CI 1.74 to 3.28), global clinical assessment measured by CDR (WMD -0.80; 95% CI -0.95 to -0.65) and CIBIC-plus (OR 4.32, 95% CI 2.37 to 7.90), behavioral disturbance measured by ADAS-non-Cog at six weeks (WMD -1.33, 95%CI -2.12 to -0.54) and at 12 weeks (WMD -1.52, 95% CI-2.39 to -0.65), and functional performance measured by ADL (WMD = -7.17; 95% CI -9.13 to -5.22; P < 0.00001). However, Huperzine A was not superior to placebo in the improvement of general cognitive function measured by Hasegawa Dementia Scale (HDS) (WMD: 2.78; 95% CI -0.17 to 5.73, P = 0.06) and specific cognitive function measured by Weshler Memory Scale (WMS) (WMD = 6.64; 95% CI -3.22 to 16.50; P = 0.19). No data were available on quality of life and caregiver burden. The adverse events of Huperzine A were mild and there were no significant differences of adverse events between Huperzine A groups and control groups.

AUTHORS' CONCLUSIONS

From the available evidence, Huperzine A seems to have some beneficial effects on improvement of general cognitive function, global clinical status, behavioral disturbance and functional performance, with no obvious serious adverse events for patients with AD. However, only one study was of adequate quality and size. There is therefore inadequate evidence to make any recommendation about its use. Rigorous design, randomized, multi-centre, large-sample trials of Huperzine A for AD are needed to further assess the effects.

The use of cognitive enhancers in behavioral disturbances of Alzheimer's disease

OBJECTIVE

To review the literature for double-blind, placebo-controlled trials that examined the efficacy of cognitive enhancers in the psychopathology of Alzheimer's disease.

DATA SOURCES

Literature searches were conducted using MEDLINE and EMBASE databases and clinicaltrials.gov.

STUDY SELECTION

Overall, 55 articles were reviewed for inclusion. Several open-label studies and case reports were found on this topic, but only those involving both tacrine and use of the Neuropsychiatric Inventory were included. Regarding other drugs, only double-blind, placebo-controlled trials were selected for inclusion.

DATA SYNTHESIS

Limited data suggest that the anticholinesterase inhibitors and memantine offer an alternative or adjunct to the antipsychotics for the treatment of moderate-to-severe behaviors. The author reviewed the literature for pharmacological management of behavioral and psychological symptoms of dementia (BPSD) using these cognitive enhancers.

CONCLUSION

The majority of patients with Alzheimer's disease will experience behavioral disturbances during the course of their disease. Atypical antipsychotics are used routinely in these situations to treat the psychotic features and agitation. However, atypicals now carry a "black box" warning issued by the Food and Drug Administration on the basis of evidence that their use in geriatric patients with dementia-related psychosis may put patients at increased risk of mortality as a result of cardiovascular or infectious events. An alternative to the atypicals may be the acetylcholinesterase inhibitors and memantine, which have been shown to stabilize cognitive as well as behavioral issues in patients, utilizing the "gold standard" for behavior, the Neuropsychiatric Inventory. Efficacy varies among agents, with the greatest positive effects seen with donepezil, which also has the greatest number of studies. Drug benefits were harder to demonstrate for mild-to-moderate BPSD compared with moderate-to-severe symptoms.

Aspirin in Alzheimer's disease (AD2000): a randomised open-label trial

BACKGROUND

Cardiovascular risk factors and a history of vascular disease can increase the risk of Alzheimer's disease (AD). AD is less common in aspirin users than non-users, and there are plausible biological mechanisms whereby aspirin might slow the progression of either vascular or Alzheimer-type pathology. We assessed the benefits of aspirin in patients with AD.

METHODS

310 community-resident patients who had AD and who had no potential indication or definite contraindication for aspirin were randomly assigned to receive open-label aspirin (n=156; one 75-mg enteric-coated tablet per day, to continue indefinitely) or to avoid aspirin (n=154). Primary outcome measures were cognition (assessed with the mini-mental state examination [MMSE]) and functional ability (assessed with the Bristol activities of daily living scale [BADLS]). Secondary outcomes were time to formal domiciliary or institutional care, progress of disability, behavioural symptoms, caregiver wellbeing, and care time. Patients were assessed at 12-week intervals in the first year and once each year thereafter. Analysis of the primary outcome measures was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN96337233.

FINDINGS

Patients had a median age of 75 years; 156 patients had mild AD, 154 had moderate AD, and 18 had concomitant vascular dementia. Over the 3 years after randomisation, in patients who took aspirin, mean MMSE score was 0.10 points higher (95% CI -0.37 to 0.57; p=0.7) and mean BADLS score was 0.62 points lower (-1.37 to 0.13; p=0.11) than in patients assigned to aspirin avoidance. There were no obvious differences between the groups in any other outcome measurements. 13 (8%) patients on aspirin and two (1%) patients in the control group had bleeds that led to admission to hospital (relative risk=4.4, 95% CI 1.5-12.8; p=0.007); three (2%) patients in the aspirin group had fatal cerebral bleeds.

INTERPRETATION

Although aspirin is commonly used in dementia, in patients with typical AD 2 years of treatment with low-dose aspirin has no worthwhile benefit and increases the risk of serious bleeds.

Prise en charge de la maladie d'Alzheimer

Management of Alzheimer disease is based on drug and nondrug treatments. Specific drug treatment includes acetylcholinesterase inhibitors and memantine. They show moderate efficacy superior to that of placebo for global condition, cognitive disorders, need for care, and behavioral problems, but do not prevent further decline. These treatments remain underused. The efficacy of psychotropic drugs (antidepressants, neuroleptics, and antipsychotic agents) in treating behavioral problems is not well documented. Nondrug activities and interventions have not been sufficiently evaluated scientifically. These involve interventions against the consequences of the disease (loss of autonomy, malnutrition) and helping patients' family caregivers. Among these activities, the best evaluated and most interesting are: educational programs for caregivers, occupational therapy at home, and interventions at home by nurses specially trained as case managers.

Efficacy and adverse effects of cholinesterase inhibitors and memantine in vascular dementia: a meta-analysis of randomised controlled trials

BACKGROUND

Cholinesterase inhibitors and memantine do not have regulatory approval in most of the world for treatment of vascular dementia. A systematic review and meta-analysis was undertaken to assess the evidence for efficacy and safety of cholinesterase inhibitors and memantine in vascular dementia.

METHODS

PubMed, BIOSIS, International Pharmaceutical Abstracts, and Cochrane registries were searched for randomised, placebo-controlled trials on cholinesterase inhibitors and memantine in patients with vascular dementia. Trial methods, clinical characteristics, outcomes, and adverse events were extracted and checked. Meta-analytic methods using fixed-effects models were used to give summaries of each drug's effects.

FINDINGS

Three donepezil, two galantamine, one rivastigmine, and two memantine trials, comprising 3093 patients on the study drugs and 2090 patients on placebo, met the selection criteria. Trials were of 6-month duration with similar vascular dementia criteria and outcome measures. Cognitive effects on the Alzheimer's Disease Assessment scale were significant for all drugs, ranging from a -1.10 point mean difference (95% CI -2.15 to -0.05) for rivastigmine to -2.17 for 10 mg daily donepezil (95% CI -2.98 to -1.35). Only 5 mg daily donepezil had an effect on the Clinicians' Global Impression of Change scale (odds ratio 1.51 [95% CI 1.11-2.07]). No behavioural or functional benefits were observed, except for a -0.95 point difference (95% CI -1.74 to -0.16) with 10 mg daily donepezil on the Alzheimer's Disease Functional Assessment and Change Scale. Compared with placebo, more dropouts and adverse events (anorexia, nausea, vomiting, diarrhoea, and insomnia) occurred with the cholinesterase inhibitors, but not with memantine.

INTERPRETATION

Cholinesterase inhibitors and memantine produce small benefits in cognition of uncertain clinical significance in patients with mild to moderate vascular dementia. Data are insufficient to support widespread use of these drugs in vascular dementia. Individual patient analyses are needed to identify subgroups of patients with vascular dementia who might benefit.

Agonist concentration dependency of blocking kinetics but not equilibrium block of N-methyl-d-aspartate receptors by memantine

Memantine is an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist which is registered in both Europe and the USA for the treatment of Alzheimer's disease (AD). Cultured rat hippocampal neurons were used to evaluate the potency and blocking kinetics of this therapeutically very well-tolerated agent in the presence of various concentrations of the synthetic agonist NMDA and a constant, saturating concentration of the co-agonist D-serine (10 microM). Whole-cell patch-clamp experiments at -70 mV revealed that the degree of "equilibrium" blockade of NMDA-induced currents by memantine was largely unaffected by the concentration of the agonist NMDA. The IC50 values for NMDA at 300, 100, 30 and 10 microM were 0.80+/-0.12, 1.01+/-0.08, 0.92+/-0.13 and 1.31+/-0.09 microM, respectively, giving an average IC(50) for all agonists concentrations tested of 1.01+/-0.11 microM. In contrast, and as expected, the onset and offset kinetics of blockade were clearly dependent on agonist concentration. For NMDA 300, 100, 30 and 10 microM, kon values were 10.55+/-1.41, 8.60+/-0.17, 4.90+/-0.20 and 3.22+/-0.08x10(4) M(-1) s(-1), respectively; 1/tauon values at the IC50 concentration of memantine-i.e. 1 microM-were 0.58+/-0.11, 0.28+/-0.05, 0.15+/-0.02 and 0.11+/-0.03 s(-1), respectively and koff values were 0.24+/-0.01, 0.19+/-0.01, 0.14+/-0.00 and 0.09+/-0.01 s(-1), respectively. It therefore appears that the kinetics, but not the equilibrium potency, of memantine are agonist concentration-dependent. These fast agonist concentration-dependent kinetic properties, in addition to the clear voltage-dependence of memantine, are proposed to be important for the therapeutic tolerability of this compound in the treatment of AD.

Memantine: a NMDA receptor antagonist that improves memory by restoration of homeostasis in the glutamatergic system--too little activation is bad, too much is even worse

The neurotransmitter glutamate activates several classes of metabotropic receptor and three major types of ionotropic receptor--alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate and N-methyl-D-aspartate (NMDA). The involvement of glutamate mediated neurotoxicity in the pathogenesis of Alzheimer's disease (AD) is finding increasing scientific acceptance. Central to this hypothesis is the assumption that glutamate receptors, in particular of the NMDA type, are overactivated in a tonic rather than a phasic manner. Such continuous, mild, chronic activation ultimately leads to neuronal damage/death. Additionally, impairment of synaptic plasticity (learning) may result not only from neuronal damage per se but may also be a direct consequence of this continuous, non-contingent NMDA receptor activation. Complete NMDA receptor blockade has also been shown to impair neuronal plasticity, thus, both hypo- and hyperactivity of the glutamatergic system leads to dysfunction. Memantine received marketing authorization from the EMEA (European Medicines Agency) for the treatment of moderate to severe AD in Europe and was subsequently also approved by the FDA (Food and Drug Administration) for use in the same indication in the USA. Memantine is a moderate affinity, uncompetitive NMDA receptor antagonist with strong voltage-dependency and fast kinetics. This review summarizes existing hypotheses on the mechanism of action (MOA) of memantine in an attempt to understand how the accepted interaction with NMDA receptors could allow memantine to provide both neuroprotection and reverse deficits in learning/memory by the same MOA.

Cost-effectiveness of memantine compared with standard care in moderate-to-severe Alzheimer disease in Canada

OBJECTIVE

To conduct a cost-effectiveness analysis comparing the addition of memantine to standard care (that is, without acetylcholinesterase inhibitors) with standard care alone in moderate-to-severe Alzheimer disease (AD) in Canada.

METHODS

A 2-year Markov model estimated clinical effects in terms of quality-adjusted life years (QALYs) and time in complete dependence as well as societal costs in four 6-month cycles. Health states were defined by AD severity assessed with the Mini-Mental State Examination (moderate = 10 to 19; severe < 10), by level of dependence in activities of daily living, and by death. Transition probabilities were estimated by combining data of patients with moderate-to-severe AD from all relevant clinical trials. QALYs were estimated from a UK epidemiologic study. The initial distribution and use of medical and support services for each health state was obtained from the Canadian Study on Health and Aging with current estimates of frequency of use and unit prices applied.

RESULTS

Compared with standard care, the memantine strategy saved more than 1 month of complete dependence and produced 0.03 additional QALYs, with no additional cost. Probabilistic sensitivity analyses give an 83.3% chance that memantine treatment is cost-neutral, an 89.5% chance of its being cost-effective if the decision maker is willing to pay $20 000 for a QALY, and a 96.2% chance with a willingness to pay $100 000 per QALY. Robustness of results was confirmed through 1-way and scenario-based sensitivity analyses.

CONCLUSIONS

Our evaluation found that memantine monotherapy produced relevant health benefit, compared with standard care alone, with no additional costs. Results are consistent with other economic evaluations of memantine conducted in Europe and the United States.

Chronic administration of R-flurbiprofen attenuates learning impairments in transgenic amyloid precursor protein mice

Background

Long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced incidence of Alzheimer's disease (AD). We and others have shown that certain NSAIDs reduce secretion of Aβ42 in cell culture and animal models, and that the effect of NSAIDs on Aβ42 is independent of the inhibition of cyclooxygenase by these compounds. Since Aβ42 is hypothesized to be the initiating pathologic molecule in AD, the ability of these compounds to lower Aβ42 selectively may be associated with their protective effect. We have previously identified R-flurbiprofen (tarenflurbil) as a selective Aβ42 lowering agent with greatly reduced cyclooxygenase activity that shows promise for testing this hypothesis. In this study we report the effect of chronic R-flurbiprofen treatment on cognition and Aβ loads in Tg2576 APP mice.

Results

A four-month preventative treatment regimen with R-flurbiprofen (10 mg/kg/day) was administered to young Tg2576 mice prior to robust plaque or Aβ pathology. This treatment regimen improved spatial learning as assessed by the Morris water maze, indicated by an increased spatial bias during the third probe trial and an increased utilization of a place strategy to solve the water maze. These results are consistent with an improvement in hippocampal- and medial temporal lobe-dependent memory function. A modest, though not statistically significant, reduction in formic acid-soluble levels of Aβ was also observed. To determine if R-flurbiprofen could reverse cognitive deficits in Tg2576 mice where plaque pathology was already robust, a two-week therapeutic treatment was given to older Tg2576 mice with the same dose of R-flurbiprofen. This approach resulted in a significant decrease in Aβ plaque burden but no significant improvement in spatial learning.

Conclusion

We have found that chronic administration of R-flurbiprofen is able to attenuate spatial learning deficits if given prior to plaque deposition in Tg2576 mice. Given its ability to selectively target Aβ42 production and improve cognitive impairments in transgenic APP mice, as well as promising data from a phase 2 human clinical trial, future studies are needed to investigate the utility of R-flurbiprofen as an AD therapeutic and its possible mechanisms of action.

[Clinical aspects of Alzheimer disease]

Alzheimer disease is diagnosed in only half of the patients with this disease in France. In its typical form, it is characterized at the onset by short-term memory problems, repetitive and unusual oversights and forgetfulness, and difficulties in learning new information. Dementia is responsible for more than 50% of the need for care in the elderly. Disease progression is accompanied by noncognitive complications. The 3 most frequent are psychological and behavioral symptoms, weight loss, and impaired balance and walking. Its progressive nature and potential complications underline the need for multidisciplinary management for patients and their families, with regular medical follow-up.

Disease-modifying therapies in Alzheimer's disease: how far have we come?

Currently, there are no disease-modifying therapies available for Alzheimer's disease (AD). Acetylcholinesterase inhibitors and memantine are licensed for AD and have moderate symptomatic benefits. Epidemiological studies have suggested that NSAIDs, estrogen, HMG-CoA reductase inhibitors (statins) or tocopherol (vitamin E) can prevent AD. However, prospective, randomised studies have not convincingly been able to demonstrate clinical efficacy. Major progress in molecular medicine suggests further drug targets. The metabolism of the amyloid-precursor protein and the aggregation of its Abeta fragment are the focus of current studies. Abeta peptides are produced by the enzymes beta- and gamma-secretase. Inhibition of gamma-secretase has been shown to reduce Abeta production. However, gamma-secretase activity is also involved in other vital physiological pathways. Involvement of gamma-secretase in cell differentiation may preclude complete blockade of gamma-secretase for prolonged times in vivo. Inhibition of beta-secretase seems to be devoid of serious adverse effects according to studies with knockout animals. However, targeting beta-secretase is hampered by the lack of suitable inhibitors to date. Other approaches focus on enzymes that cut inside the Abeta sequence such as alpha-secretase and neprilysin. Stimulation of the expression or activity of alpha-secretase or neprilysin has been shown to enhance Abeta degradation. Furthermore, inhibitors of Abeta aggregation have been described and clinical trials have been initiated. Peroxisome proliferator activated receptor-gamma agonists and selected NSAIDs may be suitable to modulate both Abeta production and inflammatory activation. On the basis of autopsy reports, active immunisation against Abeta in humans seems to have proven its ability to clear amyloid deposits from the brain. However, a first clinical trial with active vaccination against the full length Abeta peptide has been halted because of adverse effects. Further trials with vaccination or passive transfer of antibodies are planned.

Disease progression in vascular cognitive impairment: Cognitive, functional and behavioural outcomes in the Consortium to Investigate Vascular Impairment of Cognition (CIVIC) cohort study

BACKGROUND AND PURPOSE

Empirical studies to clarify the outcomes in Vascular Cognitive Impairment (VCI) are needed. We compared cognitive, functional, and behavioural outcomes in patients with VCI to patients with no cognitive impairment (NCI), and Alzheimer's disease (AD).

METHODS

Secondary analysis of the Consortium to Investigate Vascular Impairment of Cognition (CIVIC), a multi-centre Canadian memory clinic 30-month cohort study.

RESULTS

Of 1347 patients, 938 were eligible for follow-up, of whom 239 (24.5%) were lost and 29 (3%) had died. Of the remaining 697 patients, 125 had NCI, 229 had VCI, and 343 had AD at baseline. Compared to people with NCI, of whom 20-40% showed progression based on cognitive and functional measures, those with VCI were more likely to progress (50-65%), as were people with AD (50-80%) (p<0.01). More people with VCI showed progression of affective symptoms (30%) than those with NCI (12%) or AD (15% p<0.01). Progression of impaired judgment (rated clinically) in VCI (15%) was similar to AD (11%) but more common than in NCI (4%, p<0.01).

CONCLUSIONS

Most people with VCI show readily detectable progression by 30 months. Depressive symptoms were more common and more progressive in VCI than in Alzheimer's disease, whereas clinical evidence of progressive executive dysfunction was common in both AD and VCI.

100 years and counting: prospects for defeating Alzheimer's disease

This week marks a century since the first description of Alzheimer's disease (AD). Despite approval of several drugs for AD, the disease continues to rob millions of their memories and their lives. Fortunately, many new therapies directly targeting the mechanisms underlying AD are now in the pipeline. Among the investigative AD therapies in clinical trials are several strategies to block pathogenic amyloid-beta peptides and to rescue vulnerable neurons from degeneration. Complementary but less mature strategies aim to prevent the copathogenic effects of apolipoprotein E and the microtubule-associated protein tau. New insights into selective neuronal vulnerability and the link between aging and AD may provide additional entry points for therapeutic interventions. The predicted increase in AD cases over the next few decades makes the development of better treatments a matter of utmost importance and urgency.