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Targeting Microglia in Alzheimer’s Disease: From Molecular Mechanisms to Potential Therapeutic Targets for Small Molecules. Molecules 2022; 27:molecules27134124. [PMID: 35807370 PMCID: PMC9268715 DOI: 10.3390/molecules27134124] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 02/01/2023] Open
Abstract
Alzheimer’s disease (AD) is a common, progressive, and devastating neurodegenerative disorder that mainly affects the elderly. Microglial dysregulation, amyloid-beta (Aβ) plaques, and intracellular neurofibrillary tangles play crucial roles in the pathogenesis of AD. In the brain, microglia play roles as immune cells to provide protection against virus injuries and diseases. They have significant contributions in the development of the brain, cognition, homeostasis of the brain, and plasticity. Multiple studies have confirmed that uncontrolled microglial function can result in impaired microglial mitophagy, induced Aβ accumulation and tau pathology, and a chronic neuroinflammatory environment. In the brain, most of the genes that are associated with AD risk are highly expressed by microglia. Although it was initially regarded that microglia reaction is incidental and induced by dystrophic neurites and Aβ plaques. Nonetheless, it has been reported by genome-wide association studies that most of the risk loci for AD are located in genes that are occasionally uniquely and highly expressed in microglia. This finding further suggests that microglia play significant roles in early AD stages and they be targeted for the development of novel therapeutics. In this review, we have summarized the molecular pathogenesis of AD, microglial activities in the adult brain, the role of microglia in the aging brain, and the role of microglia in AD. We have also particularly focused on the significance of targeting microglia for the treatment of AD.
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Long-term use of pharmacological treatment in Alzheimer's disease: a retrospective cohort study in real-world clinical practice. Eur J Clin Pharmacol 2022; 78:1155-1163. [PMID: 35484251 DOI: 10.1007/s00228-022-03325-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 04/18/2022] [Indexed: 01/26/2023]
Abstract
PURPOSE To assess the impact of long-term use of different drugs commonly prescribed in Alzheimer's disease (AD) on its clinical course and to identify clinical and therapeutic factors associated with a delay in AD progression. METHODS We retrospectively enrolled 50 patients visited at the Neurology Unit, Careggi University Hospital (Florence), followed for at least 24 months. AD diagnosis was made according to clinical diagnostic criteria for probable/possible AD dementia, always supported at least by one biomarker. Clinical features, MMSE scores evaluated at diagnosis and every 6 months, and AD drugs used for at least 6 months, were recorded. Cox regression analysis was performed to estimate the hazard ratio (HR) for AD progression, assuming as the "final event," the progression to a more severe disease stage, defined as the achievement of an MMSE score less than 10. RESULTS At baseline, the median MMSE score was 22. During follow-up (median of 41 months), 56% of patients progressed to a more severe disease stage. The use of memantine, either alone (HR 0.24; 95% CI 0.09-0.60) or combined with acetylcholinesterase inhibitors (HR 0.35; 95% CI 0.14-0.88) and a higher MMSE score at baseline (HR 0.82; 95% CI 0.70-0.96) were associated with a significantly lower risk of AD progression. CONCLUSION Nowadays, effective disease-modifying therapy for AD is missing. Nevertheless, when the diagnosis is established, our results support the advantage of long-term use of available pharmacological treatments, especially in combination, in delaying AD progression to its more severe disease stage.
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Svob Strac D, Konjevod M, Sagud M, Nikolac Perkovic M, Nedic Erjavec G, Vuic B, Simic G, Vukic V, Mimica N, Pivac N. Personalizing the Care and Treatment of Alzheimer's Disease: An Overview. Pharmgenomics Pers Med 2021; 14:631-653. [PMID: 34093032 PMCID: PMC8169052 DOI: 10.2147/pgpm.s284615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 05/05/2021] [Indexed: 11/23/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive, complex, and multifactorial neurodegenerative disorder, still without effective and stable therapeutic strategies. Currently, available medications for AD are based on symptomatic therapy, which include acetylcholinesterase (AChE) inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonist. Additionally, medications such as antipsychotic drugs, antidepressants, sedative, and hypnotic agents, and mood stabilizers are used for the management of behavioral and psychological symptoms of dementia (BPSD). Clinical research has been extensively investigated treatments focusing on the hallmark pathology of AD, including the amyloid deposition, tau hyperphosphorylation, neuroinflammation, and vascular changes; however, so far without success, as all new potential drugs failed to show significant clinical benefit. The underlying heterogeneous etiology and diverse symptoms of AD suggest that a precision medicine strategy is required, which would take into account the complex genetic, epigenetic, and environmental landscape of each AD patient. The article provides a comprehensive overview of the literature on AD, the current and potential therapy of both cognitive symptoms as well as BPSD, with a special focus on gut microbiota and epigenetic modifications as new emerging drug targets. Their specific patterns could represent the basis for novel individually tailored approaches aimed to optimize precision medicine strategies for AD prevention and treatment. However, the successful application of precision medicine to AD demands a further extensive research of underlying pathological processes, as well as clinical and biological complexity of this multifactorial neurodegenerative disorder.
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Affiliation(s)
- Dubravka Svob Strac
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Marcela Konjevod
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Marina Sagud
- Department of Psychiatry, Clinical Hospital Centre Zagreb, Zagreb, Croatia
- University of Zagreb Medical School, Zagreb, Croatia
| | - Matea Nikolac Perkovic
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Gordana Nedic Erjavec
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Barbara Vuic
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Goran Simic
- Department of Neuroscience, Croatian Institute for Brain Research, Zagreb, Croatia
| | - Vana Vukic
- Department of Neuroscience, Croatian Institute for Brain Research, Zagreb, Croatia
| | | | - Nela Pivac
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
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Miziak B, Błaszczyk B, Czuczwar SJ. Some Candidate Drugs for Pharmacotherapy of Alzheimer's Disease. PHARMACEUTICALS (BASEL, SWITZERLAND) 2021; 14:ph14050458. [PMID: 34068096 PMCID: PMC8152728 DOI: 10.3390/ph14050458] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022]
Abstract
Alzheimer’s disease (AD; progressive neurodegenerative disorder) is associated with cognitive and functional impairment with accompanying neuropsychiatric symptoms. The available pharmacological treatment is of a symptomatic nature and, as such, it does not modify the cause of AD. The currently used drugs to enhance cognition include an N-methyl-d-aspartate receptor antagonist (memantine) and cholinesterase inhibitors. The PUBMED, Medical Subject Heading and Clinical Trials databases were used for searching relevant data. Novel treatments are focused on already approved drugs for other conditions and also searching for innovative drugs encompassing investigational compounds. Among the approved drugs, we investigated, are intranasal insulin (and other antidiabetic drugs: liraglitude, pioglitazone and metformin), bexarotene (an anti-cancer drug and a retinoid X receptor agonist) or antidepressant drugs (citalopram, escitalopram, sertraline, mirtazapine). The latter, especially when combined with antipsychotics (for instance quetiapine or risperidone), were shown to reduce neuropsychiatric symptoms in AD patients. The former enhanced cognition. Procognitive effects may be also expected with dietary antioxidative and anti-inflammatory supplements—curcumin, myricetin, and resveratrol. Considering a close relationship between brain ischemia and AD, they may also reduce post-brain ischemia neurodegeneration. An investigational compound, CN-105 (a lipoprotein E agonist), has a very good profile in AD preclinical studies, and its clinical trial for postoperative dementia is starting soon.
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Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Barbara Błaszczyk
- Faculty of Health Sciences, High School of Economics, Law and Medical Sciences, 25-734 Kielce, Poland;
| | - Stanisław J. Czuczwar
- Department of Pathophysiology, Medical University of Lublin, 20-090 Lublin, Poland;
- Correspondence: ; Tel.: +48-81-448-65-00; Fax: +48-81-65-00-01
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Cacabelos R. Pharmacogenetic considerations when prescribing cholinesterase inhibitors for the treatment of Alzheimer's disease. Expert Opin Drug Metab Toxicol 2020; 16:673-701. [PMID: 32520597 DOI: 10.1080/17425255.2020.1779700] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Cholinergic dysfunction, demonstrated in the late 1970s and early 1980s, led to the introduction of acetylcholinesterase inhibitors (AChEIs) in 1993 (Tacrine) to enhance cholinergic neurotransmission as the first line of treatment against Alzheimer's disease (AD). The new generation of AChEIs, represented by Donepezil (1996), Galantamine (2001) and Rivastigmine (2002), is the only treatment for AD to date, together with Memantine (2003). AChEIs are not devoid of side-effects and their cost-effectiveness is limited. An option to optimize the correct use of AChEIs is the implementation of pharmacogenetics (PGx) in the clinical practice. AREAS COVERED (i) The cholinergic system in AD, (ii) principles of AD PGx, (iii) PGx of Donepezil, Galantamine, Rivastigmine, Huperzine and other treatments, and (iv) practical recommendations. EXPERT OPINION The most relevant genes influencing AChEI efficacy and safety are APOE and CYPs. APOE-4 carriers are the worst responders to AChEIs. With the exception of Rivastigmine (UGT2B7, BCHE-K), the other AChEIs are primarily metabolized via CYP2D6, CYP3A4, and UGT enzymes, with involvement of ABC transporters and cholinergic genes (CHAT, ACHE, BCHE, SLC5A7, SLC18A3, CHRNA7) in most ethnic groups. Defective variants may affect the clinical response to AChEIs. PGx geno-phenotyping is highly recommended prior to treatment.
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Affiliation(s)
- Ramón Cacabelos
- Department of Genomic Medicine, EuroEspes Biomedical Research Center, International Center of Neuroscience and Genomic Medicine , Bergondo, Corunna, Spain
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Ueda K, Katayama S, Arai T, Furuta N, Ikebe S, Ishida Y, Kanaya K, Ouma S, Sakurai H, Sugitani M, Takahashi M, Tanaka T, Tsuno N, Wakutani Y, Shekhawat A, Das Gupta A, Kiyose K, Toriyama K, Nakamura Y. Efficacy, Safety, and Tolerability of Switching from Oral Cholinesterase Inhibitors to Rivastigmine Transdermal Patch with 1-Step Titration in Patients with Mild to Moderate Alzheimer's Disease: A 24-Week, Open-Label, Multicenter Study in Japan. Dement Geriatr Cogn Dis Extra 2019; 9:302-318. [PMID: 31572426 PMCID: PMC6751467 DOI: 10.1159/000501364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 01/12/2023] Open
Abstract
Background Few studies have investigated treatment options for patients with Alzheimer's disease (AD) showing a poor response to oral cholinesterase inhibitors (ChEIs) in Japan. Objective To investigate the efficacy and safety of switching from oral ChEIs to rivastigmine transdermal patch in patients with AD. Methods In this multicenter, open-label, phase IV study in outpatient clinics in Japan, patients with mild-moderate AD who had a poor response to or experienced difficulty in continuing donepezil or galantamine were switched to rivastigmine transdermal patch (5 cm2; loaded dose 9 mg, delivery rate 4.6 mg/24 h) with a 1-step titration in week 4 (10 cm2; loaded dose 18 mg, delivery rate 9.5 mg/24 h), which was continued for 4 weeks in the titration period and 16 weeks in a maintenance period. The primary endpoint was the change in Mini-Mental State Examination (MMSE) total score from baseline to week 24. Results A total of 118 patients were enrolled and switched to rivastigmine, of which 102 completed the 24-week study. The MMSE total score was essentially unchanged during the study, with a least-square mean change (SD) of −0.35 (2.64) at week 24 (p = 0.1750). Exploratory analysis with a mixed-effect model comparing changes in MMSE between the pre- and post-switch periods suggested that switching to rivastigmine prevented a worsening of MMSE. Application site skin reactions/irritations occurred in 30.5% of patients overall, in 22.0% in the 8-week titration period, and in 10.2% in the 16-week maintenance period. Conclusion Within-class switching from an oral ChEI to rivastigmine transdermal patch might be an efficacious and tolerable option for AD patients showing a poor or limited response to a prior oral ChEI.
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Affiliation(s)
| | | | - Tetsuaki Arai
- Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | | | | | | | - Kiyoshi Kanaya
- Hachioji Medical Center, Geriatric Medicine, Tokyo Medical University, Tokyo, Japan
| | - Shinji Ouma
- Department of Neurology, Fukuoka University, Fukuoka, Japan
| | - Hirofumi Sakurai
- Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan
| | | | - Makio Takahashi
- Department of Neurology, Osaka Red Cross Hospital, Osaka, Japan
| | - Toshihisa Tanaka
- Department of Psychiatry, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Norifumi Tsuno
- Department of Neuropsychiatry, Kagawa University School of Medicine, Kagawa, Japan
| | - Yosuke Wakutani
- Department of Neurology, Kurashiki Heisei Hospital, Okayama, Japan
| | - Ankita Shekhawat
- Novartis Healthcare Pvt. Ltd., Data Sciences, SSP, PLS, Hyderabad, India
| | - Ayan Das Gupta
- Novartis Healthcare Pvt. Ltd., Data Sciences, SSP, PLS, Hyderabad, India
| | | | | | - Yu Nakamura
- Department of Neuropsychiatry, Kagawa University School of Medicine, Kagawa, Japan
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Petrov AM, Lam M, Mast N, Moon J, Li Y, Maxfield E, Pikuleva IA. CYP46A1 Activation by Efavirenz Leads to Behavioral Improvement without Significant Changes in Amyloid Plaque Load in the Brain of 5XFAD Mice. Neurotherapeutics 2019; 16:710-724. [PMID: 31062296 PMCID: PMC6694340 DOI: 10.1007/s13311-019-00737-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Efavirenz, the FDA-approved anti-retroviral medication, is evaluated in the clinical trial in patients with mild cognitive impairment or early dementia due to Alzheimer's disease. Efavirenz is assessed for activation of cytochrome P450 46A1 (CYP46A1), a CNS-specific enzyme that converts cholesterol to 24-hydroxycholesterol. Cholesterol 24-hydroxylation is the major pathway for brain cholesterol removal, and a mechanism that controls brain cholesterol turnover. The present study tested efavirenz on 5XFAD mice (an Alzheimer's model) at a very low daily dose of 0.1 mg/kg body weight. Efavirenz treatment started from three months of age, after amyloid plague appearance, and continued for 6 months. This treatment led to CYP46A1 activation in the brain, enhancement of brain cholesterol turnover, behavioral improvements, reduction in microglia activation but increased astrocyte reactivity. The levels of the soluble and insoluble amyloid 40 and 42 peptides were unchanged while the number and area of the dense core amyloid plaques were slightly decreased. The measurements of the brain levels of several pre- and post-synaptic proteins (Munc13-1, PSD-95, gephyrin, synaptophysin, synapsin-1, and calbindin-D28k) suggested efavirenz effect at the synaptic level. Efavirenz treatment in the present work seems to represent a model of behavioral and other improvements independent of the levels of the amyloid peptides and provides insight into potential outcomes of the future clinical trial.
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Affiliation(s)
- Alexey M Petrov
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA
| | - Morrie Lam
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA
| | - Natalia Mast
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA
| | - Jean Moon
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA
| | - Yong Li
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA
| | - Erin Maxfield
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., Room 303, Cleveland, OH, 44106, USA.
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