Treatments for behavioural disorders in neurodegenerative diseases: drug development strategies

Towards a Non-pharmacological Intervention on Apathy in Korsakoff's Syndrome: A Systematic Narrative Review Across Different Clinical Conditions

Abstract

Apathy is a quantitative reduction of goal-directed activity, which can be observed in relation to behavior, cognition, emotions and social interaction. It is an invalidating behavioral symptom that is frequently present across different psychiatric conditions and neurocognitive disorders including Korsakoff's Syndrome (KS). In fact, apathy is one of the most severe behavioral symptoms of KS and has a major impact on the lives of patients and their relatives and other informal caregivers. However, guidelines for the treatment of apathy in KS are currently not available. This systematic narrative review provides a transdiagnostic overview of the effectiveness of different types of non-pharmacological interventions on apathy across different study populations that at symptom-level share characteristics with KS. This evidence may inform the development of an intervention targeting apathy in KS. The included study populations are dementia (due to Alzheimer's disease, or vascular dementia), Parkinson's disease, schizophrenia and traumatic brain injury. Through a stepped selection approach and with regard to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 22 systematic reviews and 32 empirical articles on the non-pharmacological treatment of apathy were identified. The results show a variety of effective non-pharmacological interventions on apathy. In conditions with severe cognitive impairments, successful interventions did not rely on intrinsic motivation, self-monitoring, or illness insight of the patients, but depend on external stimulation and behavioral activation. Since apathy is a multidimensional construct, identification of the extent and type of apathetic behavior before starting an intervention is highly recommended. Furthermore, it is important to adjust the treatment to the patients' personal interests and needs and embedded in daily care.

Trial registration

CRD42022298464 (PROSPERO).

Enhancing the neuroprotective effect of squid outer skin astaxanthin against rotenone-induced neurotoxicity in in-vitro model for Parkinson's disease

Rotenone is a widely used organic pesticide that induces neurotoxicity via inhibition of mitochondrial complex I and oxidative stress actions for the most of dopaminergic neurons as that occurring in Parkinsonism disease (PD). Astaxanthin (ASX) is a natural pigment (carotenoids) and a potent therapeutic compound due to its antioxidant and anti-inflammatory properties. The commercially important cephalopod Doryteuthis singhalensis is widely distributed in tropical and subtropical waters in World Ocean. D. singhalensis is an important source of astaxanthin that contains valuable biological active compounds with many valuable pharmacological effects. The present study evaluated the effect of astaxanthin in preventing rotenone-induced toxicity of SK-N-SH human neuroblastoma cells in an in vitro model of experimental Parkinsonism. The results revealed the strongly significant antioxidant capability of extracted squid astaxanthin in 1,1- diphenyl- 2- picrylhydrazyl (DPPH) radical scavenging activity. In addition, astaxanthin treatment based on dose dependent manner significantly attenuated rotenone induced cytotoxicity, mitochondrial dysfunction and oxidative stress in SKN- SH cells. It is concluded that the marine squid derived astaxanthin could be used as a potential neuroprotector against rotenone induced toxicity due to its antioxidant, and anti-apoptotic properties. Consequently, it could be a supportive remedy for neurodegenerative diseases like Parkinson's disease.

Role of aripiprazole in the management of behavioural and psychological symptoms of dementia: a narrative review

Behavioural and psychological symptoms of dementia affect in a great way quality of life of both patients and their caregivers, which increases the risk of patient institutionalisation when such symptoms are poorly controlled. One of the drugs that are used for controlling behavioural and psychological symptoms of dementia (BPSD) is aripiprazole. This narrative review aims to solve three basic questions. Is aripiprazole useful for the management of these symptoms? Does aripiprazole play a substantial role regarding safety and efficacy, compared with the other pharmacological options available for the same purpose? Has aripiprazole gained importance in treatment regimens of these symptoms, in current clinical practice? We conclude that aripiprazole is effective to manage BPSD. Moreover, it has shown a good safety profile compared with other antipsychotics in advanced disease and frail patients. Thus, aripiprazole has gained importance in current management algorithms for dementia patients mainly due to its efficacy regarding rapid control of agitation and aggressiveness.

Pharmacokinetic and tissue distribution study of ZCY-15, a novel compound against Alzheimer's disease, in rats by liquid chromatography-tandem mass spectrometry

ZCY-15, N-(3,5-dimethyladamatan-1-yl)-N-(3-methylphenyl) urea, is a candidate compound synthesized from the memantine structure and has been shown to be remarkably effective in treating Alzheimer's disease. To elucidate the pharmacokinetics and tissue distribution of ZCY-15 in rats after oral and intravenous administration, a rapid and selective LC-MS/MS method was established for the determination of ZCY-15 in rat plasma and tissues. According to the dissolution characteristics, the plasma samples were prepared by acetonitrile protein precipitation and carbamazepine was selected as the internal standard (IS). After separation by gradient elution using Aqela Venusil ASB C₈ (2.1 × 50 mm, 3 µm), the pretreated samples were analyzed in MRM mode in positive ESI mode. The effective detection limit of this method was 1.95-1000 ng·mL^-1. Tissue samples were collected from the heart, liver, spleen, lung, kidney, fat, muscle, brain, hippocampus, testicles or ovaries, large intestine, small intestine and stomach. The proposed method demonstrated fine precision and accuracy for analyzing ZCY-15 in selected tissues within the concentration range of standard liquid chromatography-tandem mass spectrometry. The whole analysis time was 3.6 min per sample. After oral administration, the blood and tissue concentrations of ZCY-15 in female rats were significantly higher than those in male rats. The clearance rate of ZCY-15 in female rats was lower than that in male rats. The results confirmed that there were gender differences. It has been shown that ZCY-15 could pass through the blood-brain barrier and was highly concentrated in the hippocampus. We established the first bioanalytical method to quantify ZCY-15 in rodent bio-samples for ongoing pharmacokinetic and tissue distribution studies, and the results were expected to lay foundation for the subsequent studies.

The Protective Effects of Green Tea Catechins in the Management of Neurodegenerative Diseases: A Review

BACKGROUND

The therapeutic strategies to manage neurodegenerative diseases remain limited and it is necessary to discover new agents for their prevention and control. Oxidative stress and inflammation play a main role in the pathogenesis of neurodegenerative diseases. The aim of this study is to review the effects of green tea catechins against the Neurodegenerative Diseases.

METHODS

In this study, we extensively reviewed all articles on the terms of Green tea, catechins, CNS disorders, and different diseases in PubMed, Science Direct, Scopus, and Google Scholar databases between the years 1990 and 2017.

RESULTS

The present study found that catechins, the major flavonoids in green tea, are powerful antioxidants and radical scavengers which possess the potential roles in the management of neurodegenerative diseases. Catechins modulate the cellular and molecular mechanisms through the inflammation-related NF-κB and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways.

CONCLUSION

The findings of the present review shows catechins could be effective against neurodegenerative diseases due to their antioxidation and anti-inflammation effects and the involved biochemical pathways including Nrf2 and NF-kB signaling pathways.

Ascorbic acid ameliorates behavioural deficits and neuropathological alterations in rat model of Alzheimer's disease

Exploring the links between neural pathobiology and behavioural deficits in Alzheimer's disease (AD), and investigating substances with known therapeutic advantages over subcellular mechanisms underlying these dysfunctions could advance the development of potent therapeutic molecules for AD treatment. Here we investigated the efficacy of ascorbic acid (AA) in reversing aluminium chloride (AlCl₃)-induced behavioural deficits and neurotoxic cascades within prefrontal cortex (PFC) and hippocampus of rats. A group of rats administered oral AlCl₃ (100mg/kg) daily for 15days showed degenerative changes characterised by significant weight loss, reduced exploratory/working memory, frontal-dependent motor deficits, cognitive decline, memory dysfunction and anxiety during behavioural assessments compared to control. Subsequent analysis showed that oxidative impairment-indicated by depleted superoxide dismutase and lipid peroxidation (related to glutathione-S-transferase activity), cholinergic deficits seen by increased neural acetylcholinesterase (AChE) expression and elevated lactate dehydrogenase underlie behavioural alterations. Furthermore, evidences of proteolysis were seen by reduced Nissl profiles in neuronal axons and dendrites which correspond to apoptotic changes observed in H&E staining of PFC and hippocampal sections. Interestingly, AA (100mg/kg daily for 15days) significantly attenuated behavioural deficits in rats through inhibition of molecular and cellular stressor proteins activated by AlCl_3. Our results showed that the primary mechanisms underlying AA therapeutic advantages relates closely with its abilities to scavenge free radicals, prevent membrane lipid peroxidation, modulate neuronal bioenergetics, act as AChE inhibitor and through its anti-proteolytic properties. These findings suggest that supplementing endogenous AA capacity through its pharmacological intake may inhibit progression of AD-related neurodegenerative processes and behavioural alterations.

SUR1 Receptor Interaction with Hesperidin and Linarin Predicts Possible Mechanisms of Action of Valeriana officinalis in Parkinson

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. A theoretical approach of our previous experiments reporting the cytoprotective effects of the Valeriana officinalis compounds extract for PD is suggested. In addiction to considering the PD as a result of mitochondrial metabolic imbalance and oxidative stress, such as in our previous in vitro model of rotenone, in the present manuscript we added a genomic approach to evaluate the possible underlying mechanisms of the effect of the plant extract. Microarray of substantia nigra (SN) genome obtained from Allen Brain Institute was analyzed using gene set enrichment analysis to build a network of hub genes implicated in PD. Proteins transcribed from hub genes and their ligands selected by search ensemble approach algorithm were subjected to molecular docking studies, as well as 20 ns Molecular Dynamics (MD) using a Molecular Mechanic Poison/Boltzman Surface Area (MMPBSA) protocol. Our results bring a new approach to Valeriana officinalis extract, and suggest that hesperidin, and probably linarin are able to relieve effects of oxidative stress during ATP depletion due to its ability to binding SUR1. In addition, the key role of valerenic acid and apigenin is possibly related to prevent cortical hyperexcitation by inducing neuronal cells from SN to release GABA on brain stem. Thus, under hyperexcitability, oxidative stress, asphyxia and/or ATP depletion, Valeriana officinalis may trigger different mechanisms to provide neuronal cell protection.

The pain of a heart being broken: pain experience and use of analgesics by caregivers of patients with Alzheimer's disease

BACKGROUND

It has been observed that psychical suffering (e.g. the feeling of losing a significant person) tends to reduce the physical pain tolerance threshold, as well as to increase the subjective sense of painfulness. The purpose of this study was to assess pain sensation among a group of caregivers of patients with Alzheimer's disease, and to determine the psychological factors (emotional and relational) that contribute to both pain perception and coping with pain via the use of analgesics.

METHODS

The study comprised 127 caregivers of patients with Alzheimer's disease. Questionnaires were used to elicit pain intensity, strength of emotional relationship between caregiver and patient, sense of painfulness of the loss experienced, depression level, and somatic ailments.

RESULTS

A large majority (87.4%) of participants reported pain complaints, while 93% took analgesics without a doctor's recommendation at least once a week; 8% took painkillers daily. The strongest predictors of both perceived pain and tendency to use analgesics were sense of loss and painfulness of loss in relation to the patient's deteriorating condition.

CONCLUSIONS

The pain experienced by caregivers may be connected to social pain resulting from the experience of losing someone they are close to. Caregivers may resort to excessive use of analgesics as a pain-coping strategy.

Drug repositioning approaches for the discovery of new therapeutics for Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia and represents one of the highest unmet needs in medicine today. Drug development efforts for AD have been encumbered by largely unsuccessful clinical trials in the last decade. Drug repositioning, a process of discovering a new therapeutic use for existing drugs or drug candidates, is an attractive and timely drug development strategy especially for AD. Compared with traditional de novo drug development, time and cost are reduced as the safety and pharmacokinetic properties of most repositioning candidates have already been determined. A majority of drug repositioning efforts for AD have been based on positive clinical or epidemiological observations or in vivo efficacy found in mouse models of AD. More systematic, multidisciplinary approaches will further facilitate drug repositioning for AD. Some experimental approaches include unbiased phenotypic screening using the library of available drug collections in physiologically relevant model systems (e.g. stem cell-derived neurons or glial cells), computational prediction and selection approaches that leverage the accumulating data resulting from RNA expression profiles, and genome-wide association studies. This review will summarize several notable strategies and representative examples of drug repositioning for AD.

How legislation on decisional capacity can negatively affect the feasibility of clinical trials in patients with dementia

Antipsychotic drugs are widely used to treat behavioural and psychological disturbances associated with Alzheimer's disease (AD), although only modest evidence from randomized controlled trials supports their efficacy, and increasing evidence from post-marketing surveillance shows serious adverse events associated with their use, including increased mortality. The AdCare study, a non-profit, randomized, placebo-controlled, double-blind, multicentre, pragmatic trial coordinated by the Italian National Institute of Health, aimed to evaluate the long-term safety and efficacy profiles of three atypical antipsychotic drugs (risperidone, olanzapine and quetiapine) and one conventional antipsychotic drug (haloperidol) in treating psychosis, aggression and agitation in outpatients with AD. The study was planned to be carried out in 19 clinical centres and to enrol 1000 outpatients. According to Italian law, in the case where a patient is considered unable to give informed consent, a legal representative designated by the court has to provide it. Because of difficulties in the informed consent procedure, the study had to be prematurely interrupted. From February 2009 to April 2010, 83 patients gave informed consent to participate in the trial. Fifty-six patients (68%) were included with consent given by a legal representative, while 27 patients (32%) were considered to provide personal informed consent on the basis of the results from a specifically built procedure. Patients and caregivers were offered the opportunity to participate in the trial before the occurrence of behavioural disturbances, in order to provide them with enough time to consider their participation in the study. Twenty-three patients experienced behavioural, clinically relevant symptoms and were randomized to the study drug; all randomized patients except one had consent for inclusion in the study given by legal representatives. After trial interruption, all patients taking an active drug continued treatment with the same molecule in clinical practice. Randomized controlled trials are acknowledged as the gold standard source of evidence on drug safety and efficacy. The AdCare study showed that an excessively rigid regulation can become a major obstacle while carrying out therapeutic research with incapacitated persons.

Pharmacologic treatment of apathy in dementia

Apathy in patients with dementia is common, underrecognized, and undertreated. We sought to improve understanding of the pharmacologic treatment of apathy in dementia by performing a systematic literature review of studies that used apathy outcome scales to document results of pharmacologic treatments for apathy. There is limited evidence of efficiency of pharmacotherapy for treatment of apathy in dementia. The best results were found for acetylcholinesterase inhibitors. There was some evidence of efficacy for memantine, but less evidence of efficacy for stimulants, calcium antagonists, and antipsychotics. There was no evidence to support the use of antidepressants or anticonvulsants. The research quality of studies was modest. Recommendations for standardizing research and for holistic evaluation and treatment are provided.

Biogenic amines and their metabolites in mouse brain tissue: development, optimization and validation of an analytical HPLC method

A simple and fast HPLC method based on an isocratic, reversed-phased ion-pair with amperometric end-point detection for simultaneous measurement of noradrenergic (MHPG/NA and A), dopaminergic (DOPAC, HVA/DA) and serotonergic (5-HIAA/5-HT) compounds in mouse brain tissue was developed. In order to improve the chromatographic resolution (Rs) with an acceptable total analysis time, experimental designs for multivariate optimization of the experimental conditions were applied. The optimal conditions for the separation of the eight neurotransmitters and metabolites, as well as two internal standards, i.e., DHBA and 5-HMT, were obtained using a mixture of methanol-phosphate-citric buffer (pH 3.2, 50 mM) (9:91, v/v) containing 2 mM OSA as mobile phase at 32°C on a microbore ALF-115 column (150 mm × 1.0 mm, 3 μm particle size) filled with porous C(18) silica stationary phase. In this study, a two-level fractional factorial experimental design (½ 2(K)) was employed to optimize the separation and capacity factor (k') of each molecule, leading to a good separation of all biogenic amines and their metabolites in brain tissue. A simple method for the preparation of different bio-analytical samples in phosphate-citric buffer was also developed. Results show that all molecules of interest were stabilized for at least 24 h in the matrix conditions without any antioxidants. The method was fully validated according to the requirements of SFSTP (Société Française des Sciences et Techniques Pharmaceutiques). The acceptance limits were set at ±15% of the nominal concentration. The method was found accurate over a concentration range of 4-2000 ng/ml for MHPG, 1-450 ng/ml for NA, 1-700 ng/ml for A, 1-300 ng/ml for DOPAC, 1-300 ng/ml for 5-HIAA, 1-700 ng/ml for DA, 4-2800 ng/ml for HVA and 1-350 ng/ml for 5-HT. The assay limits of detection for MHPG, NA, A, DOPAC, 5-HIAA, DA, HVA and 5-HT were 2.6, 2.8, 4.1, 0.7, 0.6, 0.8, 4.2 and 1.4 pg, respectively. It was found that the mean inter- and intra-assay relative standard deviations (RSDs) over the range of standard curve were less than 3%, the absolute and the relative recoveries were around 100%, demonstrating the high precision and accuracy, and reliability of the analytical method described to apply in routine analysis of biogenic amines and their metabolites in brain tissue.

Challenges to demonstrating disease-modifying effects in Alzheimer's disease clinical trials

Progress in understanding the molecular biology of Alzheimer's disease (AD) has provided a number of plausible therapeutic targets for disease-modifying interventions. To advance these agents toward eventual US Food and Drug Administration (FDA) approval and incorporation into clinical practice by physicians and acceptance by patients and caregivers it is necessary to reach consensus on the meaning of disease modification and on what information is needed to provide a compelling factual basis for distinguishing disease modification from symptomatic treatment effects. Disease modification requires that the intervention have an impact of underlying pathology and pathophysiology of AD; disease course modification, illness modification or disability sparing are alternate terminologies that could be applied to symptomatic agents that do not affect the underlying neurobiology of AD. A variety of trial designs have been proposed to provide information supporting disease modification including change from baseline designs, survival type designs, staggered start designs, and staggered withdrawal designs. Each of these has shortcomings, and by themselves trial designs are not likely to provide sufficient information to conclusively prove that disease modification has occurred. Incorporation of a biomarker into clinical trials will support the claim for disease modification. Such a surrogate marker ideally should respond to the intervention, predict the clinical response to the intervention, and be compellingly related to the neurobiology of AD in the pathway affected by the intervention. A third axis of information supportive of disease modification is derived from observation of the effect of treatment in animal models of AD. The triad of a clinical outcome consistent with disease modification, support from a surrogate marker incorporated into the clinical trial, and basic science information indicating the effect of the therapy on a model of AD would combine to make a convincing case for disease modification.

Cytoprotective effect of Valeriana officinalis extract on an in vitro experimental model of Parkinson disease

Parkinson's disease (PD) is one of the most important neurodegenerative worldwide disorders. The potential cytoprotective effects of aqueous extract of Valeriana officinalis on rotenone-induced apoptosis in human neuroblastoma SH-SY5Y cells were demonstrated. The cytotoxicity, cell viability and analysis of cellular morphology were performed by MTT-tetrazole (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and phase contrast microscopy, respectively. Significant changes in the cellular morphology, and condensation of the cell body could be observed when cells were treated with 300 nM rotenone for 48 h. Three different concentrations of Valeriana officinalis extract were used (0.049, 0.098 and 0.195 mg/mL). These extracts brought about an increase of 7.0 +/- 1.3%, 14.5 +/- 1.3% and 14.5 +/- 3.2% in cell viability. Our results indicated that neuroprotector action of the Valeriana officinalis extract provides support for later studies as they help understanding this drug for the development of cytoprotective various therapies in PD.

Consistency of neuropsychiatric syndromes across dementias: results from the European Alzheimer Disease Consortium. Part II

BACKGROUND/AIMS

The aim of this study was to determine the consistency of neuropsychiatric subsyndromes of the Neuropsychiatric Inventory across several clinical and demographic subgroups (e.g. dementia subtypes, dementia severity, medication use, age and gender) in a large sample of outpatients with dementia.

METHODS

Cross-sectional data of 2,808 patients with dementia from 12 centres from the European Alzheimer's Disease Consortium were collected. Principal component analysis was used for factor analysis. Subanalyses were performed for dementia subtypes, dementia severity, medication use, age and gender.

RESULTS

The results showed the relatively consistent presence of the 4 neuropsychiatric subsyndromes 'hyperactivity', 'psychosis', 'affective symptoms' and 'apathy' across the subanalyses. The factor structure was not dependent on dementia subtypes, age and gender but was dependent on dementia severity and cholinesterase use. The factors hyperactivity and affective symptoms were present in all subanalyses, but the presence of the factors apathy and psychosis was dependent on use of cholinesterase inhibitors and dementia severity, respectively.

CONCLUSION

The present study provided evidence of the relative consistency of neuropsychiatric subsyndromes across dementia subtypes, age and gender, thereby stressing the importance of thinking about neuropsychiatric subsyndromes instead of separate symptoms. However, the subsyndromes apathy and psychosis were dependent on use of cholinesterase inhibitors and dementia severity.

A systematic review of the effectiveness of rivastigmine for the treatment of behavioral disturbances in dementia and other neurological disorders

BACKGROUND

Dementia is frequently associated with behavioral disturbances, some of which have a significant impact on patient quality of life and the likelihood of institutionalization. Cholinergic systems, among other neurotransmitters in the brain, appear to be involved with different behaviors, such as psychosis, depression, agitation, and personality changes.

SCOPE

This paper reviews the clinical data on the effectiveness of rivastigmine, a dual inhibitor of acetylcholinesterase and butyrylcholinesterase, in ameliorating behavioral disturbances in different patient populations. Relevant articles were identified through MEDLINE searches with no date restrictions.

FINDINGS

In particular, rivastigmine has shown efficacy in treating behavioral disturbances in patients with a wide range of dementias - Alzheimer's disease, vascular dementia, fronto-temporal dementia, mixed dementia, Lewy body dementia, Parkinson's disease with dementia, and schizophrenia with dementia. Most of the studies have been open-label clinical trials with behavior as a secondary endpoint. The behavior domains that most consistently showed improvement were apathy/indifference, anxiety, delusions (psychosis), and hallucinations. The major limitation of this review is that the effects on behavioral symptoms were usually secondary endpoints in clinical trials.

CONCLUSION

The efficacious effects of treatment with rivastigmine on various behavioral disturbances provide supporting evidence that cholinergic mechanisms, among other neurotransmitters, are involved in the manifestation of some behavioral and psychological symptoms of dementia.

Asymmetric Synthesis of 3-Oxa-15-deoxy-16-(m-tolyl)-17,18,19,20-tetranorisocarbacyclin and Its Neuroprotective Analogue 15-Deoxy-16-(m-tolyl)-17,18,19,20-tetranorisocarbacyclin Based on the Conjugate Addition–Azoalkene–Asymmetric Olefination Strategy

A fully stereocontrolled synthesis of 3-oxa-15-deoxy-16-(m-tolyl)-17,18,19,20-tetranorisocarbacyclin (3-oxa-15-deoxy-TIC, 7 b) and a formal one of 15-deoxy-16-(m-tolyl)-17,18,19,20-tetranorisocarbacyclin (15-deoxy-TIC, 7 a) are described. 15-Deoxy-TIC is specific for the neuronal prostacyclin receptor (IP2) and exhibits neuroprotective activities, and the new 3-oxa-15-deoxy-TIC is expected to be metabolically more stable than 15-deoxy-TIC. The syntheses of 7 a and 7 b are based on the convergent conjugate addition-azoalkene-asymmetric olefination strategy. Key building blocks are the readily available bicyclic azoalkene 14 and the alkenylcopper derivative 15. The stereoselective conjugate addition of 15 to 14 gave hydrazone 13, which was stereoselectively converted to the bicyclic ketone 11. The key steps for the construction of the alpha side chain of 7 a and 7 b and the regioselective introduction of the endocyclic Delta6,6a double bond are: 1) a highly selective asymmetric olefination of ketone 11 with the chiral Horner-Wadsworth-Emmons reagent 28 and 2) a regioselective deconjugation of the alpha,beta-unsaturated ester (E)-10 with the chiral lithium amide 29, which gave the beta,gamma-unsaturated ester anti-9 with high selectivity. The homoallylic alcohol 8 served at a late stage as the joint intermediate in the syntheses of 7 a and 7 b. While an etherification of 8 furnished, after hydrolysis and deprotection, 3-oxa-15-deoxy-TIC, its alkylation afforded alcohol 37, the known precursor for the synthesis of 15-deoxy-TIC.

Behavioral correlates of GABAergic disruption in Alzheimer's disease

BACKGROUND

Losses of gamma-aminobutyric acid (GABA) have been variably demonstrated in Alzheimer's disease (AD) and may be related to the presence of behavioral and psychological symptoms of dementia (BPSD) in AD. Our objective was to assess the relationship between plasma GABA (pGABA) levels and specific BPSD in patients with severe AD.

METHODS

pGABA levels and BPSD were measured in 14 institutionalized AD patients (8M/6F, mean age +/- S.D. = 85.6 +/- 4.5 years) with severe cognitive impairment (Mini-mental State Examination score = 4.5 +/- 4.6) and prominent behavioral disturbances (Neuropsychiatric Inventory (NPI) score = 33.4 +/- 23.6).

RESULTS

pGABA was positively correlated with depression and apathy scores on the NPI and negatively correlated with age. Apathy and age were independent predictors of pGABA levels.

CONCLUSIONS

The final stages of AD are associated with GABAergic changes, which may contribute to depression and apathy in AD.

Multifunctional drugs with different CNS targets for neuropsychiatric disorders

The multiple disease etiologies that lead to neuropsychiatric disorders, such as Parkinson's and Alzheimer's disease, amyotrophic lateral sclerosis, Huntington disease, schizophrenia, depressive illness and stroke, offer significant challenges to drug discovery efforts aimed at preventing or even reversing the progression of these disorders. Transcriptomic tools and proteomic profiling have clearly indicated that such diseases are multifactorial in origin. Further, they are thought to be initiated by a cascade of molecular events that involve several neurotransmitter systems. In response to this complexity, a new paradigm has recently emerged that challenges the widely held assumption that 'silver bullet' agents are superior to 'dirty drugs' in therapeutic approaches aimed at the prevention or treatment of neuropsychiatric diseases. A similar pattern of drug development has occurred in strategies for the treatment of cancer, AIDS and cardiovascular diseases. In this review, we offer an overview of therapeutic strategies and novel investigative drugs discovered or developed in our own and other laboratories, that address multiple CNS etiological targets associated with an array of neuropsychiatric disorders.