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Érszegi A, Viola R, Bahar MA, Tóth B, Fejes I, Vágvölgyi A, Csupor D. Not first-line antihypertensive agents, but still effective-The efficacy and safety of imidazoline receptor agonists: A network meta-analysis. Pharmacol Res Perspect 2024; 12:e1215. [PMID: 38807350 PMCID: PMC11133783 DOI: 10.1002/prp2.1215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/22/2024] [Accepted: 05/01/2024] [Indexed: 05/30/2024] Open
Abstract
Cardiovascular disorders are the leading cause of death in the world. Many organ diseases (kidney, heart, and brain) are substantially more prone to develop in people with hypertension. In the treatment of hypertension, first-line medications are recommended, while imidazoline receptor agonists are not first-line antihypertensives. Our goal was to conduct a network meta-analysis to assess the efficacy and safety of imidazoline receptor agonists. The meta-analysis was performed following the PRISMA guidelines using the PICOS format, considering the CONSORT recommendations. Studies were collected from four databases: PubMed, Cochrane Library, Web of Science, and Embase. A total of 5960 articles were found. After filtering, 27 studies remained eligible for network meta-analysis. Moxonidine reduced blood pressure in sitting position statistically significantly after 8 weeks of treatment (SBP MD: 23.80; 95% CI: 17.45-30.15; DBP MD: 10.90; 95% CI: 8.45-13.35) compared to placebo. Moreover, moxonidine reduced blood pressure more effectively than enalapril; however, this difference was not significant (SBP MD: 3.10; 95% CI: -2.60-8.80; DBP MD: 1.30; 95% CI: -1.25-3.85). Dry mouth was experienced as a side effect in the case of all imidazoline receptor agonists. After 8 weeks of treatment, the appearance of dry mouth was highest with clonidine (OR: 9.27 95% CI: 4.70-18.29) and lowest with rilmenidine (OR: 6.46 95% CI: 0.85-49.13) compared to placebo. Somnolence was less frequent with moxonidine compared to rilmenidine (OR: 0.63 95% CI: 0.17-2.31). Imidazoline receptor agonists were nearly as effective as the first-line drugs in the examined studies. However, their utility as antihypertensives is limited due to their side effects. As a result, they are not first-line antihypertensives and should not be used in monotherapy. However, in the case of resistant hypertension, they are a viable option. According to our findings, from the point of view of safety and efficacy, moxonidine appears to be the best choice among imidazoline receptor agonists.
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Affiliation(s)
- András Érszegi
- Faculty of Pharmacy, Institute of Clinical PharmacyUniversity of SzegedSzegedHungary
- Albert Szent‐Györgyi Medical CentreCentral Pharmacy, University of SzegedSzegedHungary
| | - Réka Viola
- Faculty of Pharmacy, Institute of Clinical PharmacyUniversity of SzegedSzegedHungary
- Albert Szent‐Györgyi Medical CentreCentral Pharmacy, University of SzegedSzegedHungary
| | - Muh Akbar Bahar
- Faculty of Pharmacy, Institute of Clinical PharmacyUniversity of SzegedSzegedHungary
- Department of Pharmacy, Faculty of PharmacyUniversitas HasanuddinMakassarIndonesia
| | - Barbara Tóth
- Faculty of Pharmacy, Institute of Clinical PharmacyUniversity of SzegedSzegedHungary
| | - Imola Fejes
- Department of Medicine, Albert Szent‐Györgyi Medical CentreUniversity of SzegedSzegedHungary
| | - Anna Vágvölgyi
- Department of Medicine, Albert Szent‐Györgyi Medical CentreUniversity of SzegedSzegedHungary
| | - Dezső Csupor
- Faculty of Pharmacy, Institute of Clinical PharmacyUniversity of SzegedSzegedHungary
- Institute for Translational MedicineUniversity of PécsPécsHungary
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Khasnavis S, Belliveau T, Arnsten A, Fesharaki-Zadeh A. Combined Use of Guanfacine and N-Acetylcysteine for the Treatment of Cognitive Deficits After Traumatic Brain Injury. Neurotrauma Rep 2024; 5:226-231. [PMID: 38524728 PMCID: PMC10960163 DOI: 10.1089/neur.2023.0124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024] Open
Abstract
Traumatic Brain Injury (TBI) is a significant contributor to disability across the world. TBIs vary in severity, and most cases are designated mild TBI (mTBI), involving only brief loss of consciousness and no intracranial findings on imaging. Despite this categorization, many persons continue to report persistent cognitive changes in the months to years after injury, with particular impairment in the cognitive and executive functions of the pre-frontal cortex. For these persons, there are no currently approved medications, and treatment is limited to symptom management and cognitive or behavioral therapy. The current case studies explored the use of the alpha-2A adrenoreceptor agonist, guanfacine, combined with the antioxidant, N-acetylcysteine (NAC), in the treatment of post-TBI cognitive symptoms, based on guanfacine's ability to strengthen pre-frontal cortical function, and the open-label use of NAC in treating TBI. Two persons from our TBI clinic were treated with this combined regimen, with neuropsychological testing performed pre- and post-treatment. Guanfacine + NAC improved attention, processing speed, memory, and executive functioning with minimal side effects in both persons. These results encourage future placebo-controlled trials to more firmly establish the efficacy of guanfacine and NAC for the treatment of cognitive deficits caused by TBI.
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Affiliation(s)
- Siddharth Khasnavis
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Timothy Belliveau
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Amy Arnsten
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Arman Fesharaki-Zadeh
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
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Orlando IF, Shine JM, Robbins TW, Rowe JB, O'Callaghan C. Noradrenergic and cholinergic systems take centre stage in neuropsychiatric diseases of ageing. Neurosci Biobehav Rev 2023; 149:105167. [PMID: 37054802 DOI: 10.1016/j.neubiorev.2023.105167] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/28/2023] [Accepted: 03/28/2023] [Indexed: 04/15/2023]
Abstract
Noradrenergic and cholinergic systems are among the most vulnerable brain systems in neuropsychiatric diseases of ageing, including Alzheimer's disease, Parkinson's disease, Lewy body dementia, and progressive supranuclear palsy. As these systems fail, they contribute directly to many of the characteristic cognitive and psychiatric symptoms. However, their contribution to symptoms is not sufficiently understood, and pharmacological interventions targeting noradrenergic and cholinergic systems have met with mixed success. Part of the challenge is the complex neurobiology of these systems, operating across multiple timescales, and with non-linear changes across the adult lifespan and disease course. We address these challenges in a detailed review of the noradrenergic and cholinergic systems, outlining their roles in cognition and behaviour, and how they influence neuropsychiatric symptoms in disease. By bridging across levels of analysis, we highlight opportunities for improving drug therapies and for pursuing personalised medicine strategies.
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Affiliation(s)
- Isabella F Orlando
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Australia
| | - James M Shine
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Australia
| | - Trevor W Robbins
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of Cambridge, CB2 3EB, United Kingdom
| | - James B Rowe
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, CB2 0SZ, United Kingdom
| | - Claire O'Callaghan
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Australia.
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Carey A, Fossati S. Hypertension and hyperhomocysteinemia as modifiable risk factors for Alzheimer's disease and dementia: New evidence, potential therapeutic strategies, and biomarkers. Alzheimers Dement 2023; 19:671-695. [PMID: 36401868 PMCID: PMC9931659 DOI: 10.1002/alz.12871] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/04/2022] [Accepted: 10/17/2022] [Indexed: 11/21/2022]
Abstract
This review summarizes recent evidence on how mid-life hypertension, hyperhomocysteinemia (HHcy) and blood pressure variability, as well as late-life hypotension, exacerbate Alzheimer's disease (AD) and dementia risk. Intriguingly, HHcy also increases the risk for hypertension, revealing the importance of understanding the relationship between comorbid cardiovascular risk factors. Hypertension-induced dementia presents more evidently in women, highlighting the relevance of sex differences in the impact of cardiovascular risk. We summarize each major antihypertensive drug class's effects on cognitive impairment and AD pathology, revealing how carbonic anhydrase inhibitors, diuretics modulating cerebral blood flow, have recently gained preclinical evidence as promising treatment against AD. We also report novel vascular biomarkers for AD and dementia risk, highlighting those associated with hypertension and HHcy. Importantly, we propose that future studies should consider hypertension and HHcy as potential contributors to cognitive impairment, and that uncovering the underlying molecular mechanisms and biomarkers would aid in the identification of preventive strategies.
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Affiliation(s)
- Ashley Carey
- Alzheimer’s Center at Temple, Department of Neural Sciences, Temple University Lewis Katz School of Medicine, Philadelphia
| | - Silvia Fossati
- Alzheimer’s Center at Temple, Department of Neural Sciences, Temple University Lewis Katz School of Medicine, Philadelphia
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Mumtaz I, Ayaz MO, Khan MS, Manzoor U, Ganayee MA, Bhat AQ, Dar GH, Alghamdi BS, Hashem AM, Dar MJ, Ashraf GM, Maqbool T. Clinical relevance of biomarkers, new therapeutic approaches, and role of post-translational modifications in the pathogenesis of Alzheimer's disease. Front Aging Neurosci 2022; 14:977411. [PMID: 36158539 PMCID: PMC9490081 DOI: 10.3389/fnagi.2022.977411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/18/2022] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder that causes progressive loss of cognitive functions like thinking, memory, reasoning, behavioral abilities, and social skills thus affecting the ability of a person to perform normal daily functions independently. There is no definitive cure for this disease, and treatment options available for the management of the disease are not very effective as well. Based on histopathology, AD is characterized by the accumulation of insoluble deposits of amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs). Although several molecular events contribute to the formation of these insoluble deposits, the aberrant post-translational modifications (PTMs) of AD-related proteins (like APP, Aβ, tau, and BACE1) are also known to be involved in the onset and progression of this disease. However, early diagnosis of the disease as well as the development of effective therapeutic approaches is impeded by lack of proper clinical biomarkers. In this review, we summarized the current status and clinical relevance of biomarkers from cerebrospinal fluid (CSF), blood and extracellular vesicles involved in onset and progression of AD. Moreover, we highlight the effects of several PTMs on the AD-related proteins, and provide an insight how these modifications impact the structure and function of proteins leading to AD pathology. Finally, for disease-modifying therapeutics, novel approaches, and targets are discussed for the successful treatment and management of AD.
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Affiliation(s)
- Ibtisam Mumtaz
- Laboratory of Nanotherapeutics and Regenerative Medicine, Department of Nanotechnology, University of Kashmir, Srinagar, India
| | - Mir Owais Ayaz
- Laboratory of Cell and Molecular Biology, Department of Cancer Pharmacology, CSIR-Indian Institute of Integrative Medicine, Jammu, India
- Centre for Scientific and Innovative Research, Ghaziabad, Utter Pradesh, India
| | - Mohamad Sultan Khan
- Neurobiology and Molecular Chronobiology Laboratory, Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Umar Manzoor
- Laboratory of Immune and Inflammatory Disease, Jeju Research Institute of Pharmaceutical Sciences, Jeju National University, Jeju, South Korea
| | - Mohd Azhardin Ganayee
- Laboratory of Nanotherapeutics and Regenerative Medicine, Department of Nanotechnology, University of Kashmir, Srinagar, India
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, India
| | - Aadil Qadir Bhat
- Laboratory of Cell and Molecular Biology, Department of Cancer Pharmacology, CSIR-Indian Institute of Integrative Medicine, Jammu, India
- Centre for Scientific and Innovative Research, Ghaziabad, Utter Pradesh, India
| | - Ghulam Hassan Dar
- Sri Pratap College, Cluster University Srinagar, Jammu and Kashmir, India
| | - Badrah S. Alghamdi
- Department of Physiology, Neuroscience Unit, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pre-clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Anwar M. Hashem
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohd Jamal Dar
- Laboratory of Cell and Molecular Biology, Department of Cancer Pharmacology, CSIR-Indian Institute of Integrative Medicine, Jammu, India
- Centre for Scientific and Innovative Research, Ghaziabad, Utter Pradesh, India
| | - Gulam Md. Ashraf
- Pre-clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Tariq Maqbool
- Laboratory of Nanotherapeutics and Regenerative Medicine, Department of Nanotechnology, University of Kashmir, Srinagar, India
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Hoang K, Watt H, Golemme M, Perry RJ, Ritchie C, Wilson D, Pickett J, Fox C, Howard R, Malhotra PA. Noradrenergic Add-on Therapy with Extended-Release Guanfacine in Alzheimer's Disease (NorAD): study protocol for a randomised clinical trial and COVID-19 amendments. Trials 2022; 23:623. [PMID: 35915506 PMCID: PMC9340683 DOI: 10.1186/s13063-022-06190-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/20/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Guanfacine is a α2A adrenergic receptor agonist approved for treating attention deficit hyperactivity disorder (ADHD). It is thought to act via postsynaptic receptors in the prefrontal cortex, modulating executive functions including the regulation of attention. Attention is affected early in Alzheimer's disease (AD), and this may relate to pathological changes within the locus coeruleus, the main source of noradrenergic pathways within the brain. Given that cholinergic pathways, also involved in attention, are disrupted in AD, the combination of noradrenergic and cholinergic treatments may have a synergistic effect on symptomatic AD. The primary objective of the NorAD trial is to evaluate the change in cognition with 12 weeks of treatment of extended-release guanfacine (GXR) against a placebo as a combination therapy with cholinesterase inhibitors in participants with mild to moderate Alzheimer's disease. METHODS/DESIGN NorAD is a 3-month, single-centre, randomised, double-blind, placebo-controlled, phase III trial of extended-release guanfacine (GXR) in participants with mild to moderate Alzheimer's disease. A total of 160 participants will be randomised to receive either daily guanfacine or placebo in combination with approved cholinesterase treatment for 12 weeks. The primary outcome is the change in cognition, as measured by the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), from baseline to follow-up in the treatment group compared to the placebo group. Secondary outcomes include the change in additional cognitive measures of attention (Tests of Attention: Trails A and B, digit-symbol substitution, Test of Everyday Attention and CANTAB-RVP), neuropsychiatric symptoms (Neuropsychiatric Inventory), caregiver burden (Zarit Burden Interview) and activities of daily living (Alzheimer's Disease Co-operative Study - Activities of Daily Living Inventory). From July 2020, observation of change following cessation of treatment is also being assessed. DISCUSSION There is strong evidence for early noradrenergic dysfunction in Alzheimer's disease. The NorAD trial aims to determine whether guanfacine, a noradrenergic alpha-2 agonist, improves attention and cognition when used in addition to standard cholinergic treatment. TRIAL REGISTRATION ClinicalTrials.gov NCT03116126 . Registered on 14 April 2017 EudraCT: 2016-002598-36.
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Affiliation(s)
- Karen Hoang
- Department of Brain Sciences, Imperial College London, London, UK. .,Imperial College Healthcare NHS Trust, London, UK.
| | - Hilary Watt
- Department of Public Health and Primary Care, Imperial College London, London, UK
| | - Mara Golemme
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London and the University of Surrey, London, UK
| | - Richard J Perry
- Department of Brain Sciences, Imperial College London, London, UK.,Imperial College Healthcare NHS Trust, London, UK
| | - Craig Ritchie
- Edinburgh Dementia Prevention and Centre for Clinical Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Danielle Wilson
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London and the University of Surrey, London, UK
| | - James Pickett
- Department of Brain Sciences, Imperial College London, London, UK
| | - Chris Fox
- Norwich Medical School, University of East Anglia, Norfolk, UK
| | - Robert Howard
- Division of Psychiatry, University College London, Maple House 149 Tottenham Court Road, London, W1T 7NF, UK
| | - Paresh A Malhotra
- Department of Brain Sciences, Imperial College London, London, UK.,Imperial College Healthcare NHS Trust, London, UK.,UK Dementia Research Institute Care Research and Technology Centre, Imperial College London and the University of Surrey, London, UK
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7
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Khoury R, Gallop A, Roberts K, Grysman N, Lu J, Grossberg GT. Pharmacotherapy for Alzheimer’s disease: what’s new on the horizon? Expert Opin Pharmacother 2022; 23:1305-1323. [DOI: 10.1080/14656566.2022.2097868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Rita Khoury
- Department of Psychiatry and Clinical Psychology, St. Georges Hospital University Medical Center, Beirut, Lebanon
- University of Balamand, Faculty of Medicine, Beirut, Lebanon
- Department of Psychiatry and Behavioral Neuroscience, St Louis University School of Medicine, St. Louis, Missouri, United States
| | - Amy Gallop
- Department of Psychiatry and Behavioral Neuroscience, St Louis University School of Medicine, St. Louis, Missouri, United States
| | - Kelsey Roberts
- Department of Psychiatry and Behavioral Neuroscience, St Louis University School of Medicine, St. Louis, Missouri, United States
| | - Noam Grysman
- Department of Psychiatry and Behavioral Neuroscience, St Louis University School of Medicine, St. Louis, Missouri, United States
| | - Jiaxi Lu
- Department of Psychiatry and Behavioral Neuroscience, St Louis University School of Medicine, St. Louis, Missouri, United States
| | - George T. Grossberg
- Department of Psychiatry and Behavioral Neuroscience, St Louis University School of Medicine, St. Louis, Missouri, United States
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Dahl MJ, Mather M, Werkle-Bergner M. Noradrenergic modulation of rhythmic neural activity shapes selective attention. Trends Cogn Sci 2022; 26:38-52. [PMID: 34799252 PMCID: PMC8678372 DOI: 10.1016/j.tics.2021.10.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 10/12/2021] [Accepted: 10/12/2021] [Indexed: 01/03/2023]
Abstract
During moments involving selective attention, the thalamus orchestrates the preferential processing of prioritized information by coordinating rhythmic neural activity within a distributed frontoparietal network. The timed release of neuromodulators from subcortical structures dynamically sculpts neural synchronization in thalamocortical networks to meet current attentional demands. In particular, noradrenaline modulates the balance of cortical excitation and inhibition, as reflected by thalamocortical alpha synchronization (~8-12 Hz). These neuromodulatory adjustments facilitate the selective processing of prioritized information. Thus, by disrupting effective rhythmic coordination in attention networks, age-related locus coeruleus (LC) degeneration can impair higher levels of neural processing. In sum, findings across different levels of analysis and modalities shed light on how the noradrenergic modulation of neural synchronization helps to shape selective attention.
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Affiliation(s)
- Martin J Dahl
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany; Davis School of Gerontology, University of Southern California, 90089 Los Angeles, CA, USA.
| | - Mara Mather
- Davis School of Gerontology, University of Southern California, 90089 Los Angeles, CA, USA
| | - Markus Werkle-Bergner
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany
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New therapeutics beyond amyloid-β and tau for the treatment of Alzheimer's disease. Acta Pharmacol Sin 2021; 42:1382-1389. [PMID: 33268824 PMCID: PMC8379190 DOI: 10.1038/s41401-020-00565-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/25/2020] [Indexed: 02/06/2023] Open
Abstract
As the population ages, Alzheimer's disease (AD), the most common neurodegenerative disease in elderly people, will impose social and economic burdens to the world. Currently approved drugs for the treatment of AD including cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and an N-methyl-D-aspartic acid receptor antagonist (memantine) are symptomatic but poorly affect the progression of the disease. In recent decades, the concept of amyloid-β (Aβ) cascade and tau hyperphosphorylation leading to AD has dominated AD drug development. However, pharmacotherapies targeting Aβ and tau have limited success. It is generally believed that AD is caused by multiple pathological processes resulting from Aβ abnormality, tau phosphorylation, neuroinflammation, neurotransmitter dysregulation, and oxidative stress. In this review we updated the recent development of new therapeutics that regulate neurotransmitters, inflammation, lipid metabolism, autophagy, microbiota, circadian rhythm, and disease-modified genes for AD in preclinical research and clinical trials. It is to emphasize the importance of early diagnosis and multiple-target intervention, which may provide a promising outcome for AD treatment.
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10
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Mather M. Noradrenaline in the aging brain: Promoting cognitive reserve or accelerating Alzheimer's disease? Semin Cell Dev Biol 2021; 116:108-124. [PMID: 34099360 PMCID: PMC8292227 DOI: 10.1016/j.semcdb.2021.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/19/2022]
Abstract
Many believe that engaging in novel and mentally challenging activities promotes brain health and prevents Alzheimer's disease in later life. However, mental stimulation may also have risks as well as benefits. As neurons release neurotransmitters, they often also release amyloid peptides and tau proteins into the extracellular space. These by-products of neural activity can aggregate into the tau tangle and amyloid plaque signatures of Alzheimer's disease. Over time, more active brain regions accumulate more pathology. Thus, increasing brain activity can have a cost. But the neuromodulator noradrenaline, released during novel and mentally stimulating events, may have some protective effects-as well as some negative effects. Via its inhibitory and excitatory effects on neurons and microglia, noradrenaline sometimes prevents and sometimes accelerates the production and accumulation of amyloid-β and tau in various brain regions. Both α2A- and β-adrenergic receptors influence amyloid-β production and tau hyperphosphorylation. Adrenergic activity also influences clearance of amyloid-β and tau. Furthermore, some findings suggest that Alzheimer's disease increases noradrenergic activity, at least in its early phases. Because older brains clear the by-products of synaptic activity less effectively, increased synaptic activity in the older brain risks accelerating the accumulation of Alzheimer's pathology more than it does in the younger brain.
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Affiliation(s)
- Mara Mather
- Leonard Davis School of Gerontology, Department of Psychology, & Department of Biomedical Engineering, University of Southern California, 3715 McClintock Ave, Los Angeles, CA 90089, United States.
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11
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Arnsten AFT. Guanfacine's mechanism of action in treating prefrontal cortical disorders: Successful translation across species. Neurobiol Learn Mem 2020; 176:107327. [PMID: 33075480 PMCID: PMC7567669 DOI: 10.1016/j.nlm.2020.107327] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/13/2020] [Indexed: 01/18/2023]
Abstract
The selective norepinephrine (NE) α2A-adrenoceptor (α2A-AR) agonist, guanfacine (Intuniv™), is FDA-approved for treating Attention Deficit Hyperactivity Disorder (ADHD) based on research in animals, a translational success story. Guanfacine is also widely used off-label in additional mental disorders that involve impaired functioning of the prefrontal cortex (PFC), including stress-related disorders such as substance abuse, schizotypic cognitive deficits, and traumatic brain injury. The PFC subserves high order cognitive and executive functions including working memory, abstract reasoning, insight and judgment, and top-down control of attention, action and emotion. These abilities arise from PFC microcircuits with extensive recurrent excitation through NMDAR synapses. There is powerful modulation of these synapses, where cAMP-PKA opening of nearby potassium (K+) channels can rapidly and dynamically alter synaptic strength to coordinate arousal state with cognitive state, e.g. to take PFC "offline" during uncontrollable stress. A variety of evidence shows that guanfacine acts within the PFC via post-synaptic α2A-AR on dendritic spines to inhibit cAMP-PKA-K+ channel signaling, thus strengthening network connectivity, enhancing PFC neuronal firing, and improving PFC cognitive functions. Although guanfacine's beneficial effects are present in rodent, they are especially evident in primates, where the PFC greatly expands and differentiates. In addition to therapeutic actions in PFC, stress-related disorders may also benefit from additional α2-AR actions, such as weakening plasticity in the amygdala, reducing NE release, and anti-inflammatory actions by deactivating microglia. Altogether, these NE α2-AR actions optimize top-down control by PFC networks, which may explain guanfacine's benefits in a variety of mental disorders.
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Affiliation(s)
- Amy F T Arnsten
- Dept. Neuroscience, Yale Medical School, 333 Cedar St., New Haven, CT 06510, USA.
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α 2A-adrenergic heteroreceptors are required for stress-induced reinstatement of cocaine conditioned place preference. Neuropsychopharmacology 2020; 45:1473-1481. [PMID: 32074627 PMCID: PMC7360592 DOI: 10.1038/s41386-020-0641-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/03/2020] [Accepted: 02/10/2020] [Indexed: 02/08/2023]
Abstract
The α2a-adrenergic receptor (α2a-AR) agonist guanfacine has been investigated as a potential treatment for substance use disorders. While decreasing stress-induced reinstatement of cocaine seeking in animal models and stress-induced craving in human studies, guanfacine has not been reported to decrease relapse rates. Although guanfacine engages α2a-AR autoreceptors, it also activates excitatory Gi-coupled heteroreceptors in the bed nucleus of the stria terminalis (BNST), a key brain region in driving stress-induced relapse. Thus, BNST α2a-AR heteroreceptor signaling might decrease the beneficial efficacy of guanfacine. We aimed to determine the role of α2a-AR heteroreceptors and BNST Gi-GPCR signaling in stress-induced reinstatement of cocaine conditioned place preference (CPP) and the effects of low dose guanfacine on BNST activity and stress-induced reinstatement. We used a genetic deletion strategy and the cocaine CPP procedure to first define the contributions of α2a-AR heteroreceptors to stress-induced reinstatement. Next, we mimicked BNST Gi-coupled α2a-AR heteroreceptor signaling using a Gi-coupled designer receptor exclusively activated by designer drug (Gi-DREADD) approach. Finally, we evaluated the effects of low-dose guanfacine on BNST cFOS immunoreactivity and stress-induced reinstatement. We show that α2a-AR heteroreceptor deletion disrupts stress-induced reinstatement and that BNST Gi-DREADD activation is sufficient to induce reinstatement. Importantly, we found that low-dose guanfacine does not increase BNST activity, but prevents stress-induced reinstatement. Our findings demonstrate a role for α2a-AR heteroreceptors and BNST Gi-GPCR signaling in stress-induced reinstatement of cocaine CPP and provide insight into the impact of dose on the efficacy of guanfacine as a treatment for stress-induced relapse of cocaine use.
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Sun MK. Executive functioning: perspectives on neurotrophic activity and pharmacology. Behav Pharmacol 2018; 29:592-604. [PMID: 30179884 DOI: 10.1097/fbp.0000000000000427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Executive functioning is a high-level cognitive ability, regulating other abilities and behaviors to achieve desired goals. A typical executive task can be defined as the capacity to maintain one's attention on the current task, that is, responding only to the correct but not to distractive stimuli. Impairments of executive functions, or executive dysfunctions, have a growing impact on everyday life and academic achievement and are usually an early feature, and one of the core features, in brain injury and memory and behavioral disorders. Furthermore, emerging evidence indicates that memory therapeutics cannot achieve their clinical benefits in cognition if executive dysfunction is not effectively and simultaneously treated. Improvement of executive functions might be achieved through targeting some signaling pathways in the brain, including the brain-derived neurotrophic factor signaling pathways. These agents may be useful either as stand-alone interventions for patients with executive dysfunction and/or psychiatric and memory disorders or as essential adjuncts to drugs that target the underlying pathology in various brain injury and memory and behavioral disorders.
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Affiliation(s)
- Miao-Kun Sun
- Blanchette Rockefeller Neurosciences Institute, Morgantown, West Virginia, USA
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