1
|
Liu H, He Y, Liu H, Brouwers B, Yin N, Lawler K, Keogh JM, Henning E, Lee DK, Yu M, Tu L, Zhang N, Conde KM, Han J, Yan Z, Scarcelli NA, Liao L, Xu J, Tong Q, Zheng H, Sun Z, Yang Y, Wang C, He Y, Farooqi IS, Xu Y. Neural circuits expressing the serotonin 2C receptor regulate memory in mice and humans. SCIENCE ADVANCES 2024; 10:eadl2675. [PMID: 38941473 PMCID: PMC11212768 DOI: 10.1126/sciadv.adl2675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 05/22/2024] [Indexed: 06/30/2024]
Abstract
Declined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a role in memory, but the underlying mechanisms are unknown. Here, we investigate the role of 5-HT 2C receptor (5-HT2CR) in regulating memory. Transgenic mice expressing a humanized HTR2C mutation exhibit impaired plasticity of hippocampal ventral CA1 (vCA1) neurons and reduced memory. Further, 5-HT neurons project to and synapse onto vCA1 neurons. Disruption of 5-HT synthesis in vCA1-projecting neurons or deletion of 5-HT2CRs in the vCA1 impairs neural plasticity and memory. We show that a selective 5-HT2CR agonist, lorcaserin, improves synaptic plasticity and memory in an AD mouse model. Cumulatively, we demonstrate that hippocampal 5-HT2CR signaling regulates memory, which may inform the use of 5-HT2CR agonists in the treatment of dementia.
Collapse
Affiliation(s)
- Hesong Liu
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yang He
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Hailan Liu
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Bas Brouwers
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Na Yin
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Katherine Lawler
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Julia M. Keogh
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Elana Henning
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Dong-Kee Lee
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng Yu
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Longlong Tu
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nan Zhang
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kristine M. Conde
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Junying Han
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zili Yan
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nikolas A. Scarcelli
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lan Liao
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zheng Sun
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yongjie Yang
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chunmei Wang
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yanlin He
- Pennington Biomedical Research Center, Brain Glycemic and Metabolism Control Department, Louisiana State University, Baton Rouge, LA 70808, USA
| | - I. Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Yong Xu
- USDA/ARS, Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
2
|
Collins HM, Greenfield S. Rodent Models of Alzheimer's Disease: Past Misconceptions and Future Prospects. Int J Mol Sci 2024; 25:6222. [PMID: 38892408 PMCID: PMC11172947 DOI: 10.3390/ijms25116222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/28/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease with no effective treatments, not least due to the lack of authentic animal models. Typically, rodent models recapitulate the effects but not causes of AD, such as cholinergic neuron loss: lesioning of cholinergic neurons mimics the cognitive decline reminiscent of AD but not its neuropathology. Alternative models rely on the overexpression of genes associated with familial AD, such as amyloid precursor protein, or have genetically amplified expression of mutant tau. Yet transgenic rodent models poorly replicate the neuropathogenesis and protein overexpression patterns of sporadic AD. Seeding rodents with amyloid or tau facilitates the formation of these pathologies but cannot account for their initial accumulation. Intracerebral infusion of proinflammatory agents offer an alternative model, but these fail to replicate the cause of AD. A novel model is therefore needed, perhaps similar to those used for Parkinson's disease, namely adult wildtype rodents with neuron-specific (dopaminergic) lesions within the same vulnerable brainstem nuclei, 'the isodendritic core', which are the first to degenerate in AD. Site-selective targeting of these nuclei in adult rodents may recapitulate the initial neurodegenerative processes in AD to faithfully mimic its pathogenesis and progression, ultimately leading to presymptomatic biomarkers and preventative therapies.
Collapse
Affiliation(s)
- Helen M. Collins
- Neuro-Bio Ltd., Building F5 The Culham Campus, Abingdon OX14 3DB, UK;
| | | |
Collapse
|
3
|
Wearn A, Tremblay SA, Tardif CL, Leppert IR, Gauthier CJ, Baracchini G, Hughes C, Hewan P, Tremblay-Mercier J, Rosa-Neto P, Poirier J, Villeneuve S, Schmitz TW, Turner GR, Spreng RN. Neuromodulatory subcortical nucleus integrity is associated with white matter microstructure, tauopathy and APOE status. Nat Commun 2024; 15:4706. [PMID: 38830849 PMCID: PMC11148077 DOI: 10.1038/s41467-024-48490-z] [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: 11/29/2023] [Accepted: 05/01/2024] [Indexed: 06/05/2024] Open
Abstract
The neuromodulatory subcortical nuclei within the isodendritic core (IdC) are the earliest sites of tauopathy in Alzheimer's disease (AD). They project broadly throughout the brain's white matter. We investigated the relationship between IdC microstructure and whole-brain white matter microstructure to better understand early neuropathological changes in AD. Using multiparametric quantitative magnetic resonance imaging we observed two covariance patterns between IdC and white matter microstructure in 133 cognitively unimpaired older adults (age 67.9 ± 5.3 years) with familial risk for AD. IdC integrity related to 1) whole-brain neurite density, and 2) neurite orientation dispersion in white matter tracts known to be affected early in AD. Pattern 2 was associated with CSF concentration of phosphorylated-tau, indicating AD specificity. Apolipoprotein-E4 carriers expressed both patterns more strongly than non-carriers. IdC microstructure variation is reflected in white matter, particularly in AD-affected tracts, highlighting an early mechanism of pathological development.
Collapse
Affiliation(s)
- Alfie Wearn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada.
| | - Stéfanie A Tremblay
- Department of Physics, Concordia University, Montreal, H4B 1R6, QC, Canada
- Montreal Heart Institute, Montreal, H1T 1C8, QC, Canada
- School of Health, Concordia University, Montreal, H4B 1R6, QC, Canada
| | - Christine L Tardif
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada
- McConnell Brain Imaging Centre, McGill University, Montreal, H3A 2B4, QC, Canada
- Department of Biomedical Engineering, McGill University, McGill, H3A 2B4, QC, Canada
| | - Ilana R Leppert
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada
- McConnell Brain Imaging Centre, McGill University, Montreal, H3A 2B4, QC, Canada
| | - Claudine J Gauthier
- Department of Physics, Concordia University, Montreal, H4B 1R6, QC, Canada
- Montreal Heart Institute, Montreal, H1T 1C8, QC, Canada
- School of Health, Concordia University, Montreal, H4B 1R6, QC, Canada
| | - Giulia Baracchini
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada
| | - Colleen Hughes
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada
| | - Patrick Hewan
- Department of Psychology, York University, Toronto, M3J 1P3, ON, Canada
| | | | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada
- McConnell Brain Imaging Centre, McGill University, Montreal, H3A 2B4, QC, Canada
- Douglas Mental Health University Institute-Research Center, Verdun, H4H 1R3, QC, Canada
| | - Judes Poirier
- Douglas Mental Health University Institute-Research Center, Verdun, H4H 1R3, QC, Canada
- Department of Psychiatry, McGill University, Montreal, H3A 1A1, QC, Canada
| | - Sylvia Villeneuve
- McConnell Brain Imaging Centre, McGill University, Montreal, H3A 2B4, QC, Canada
- Douglas Mental Health University Institute-Research Center, Verdun, H4H 1R3, QC, Canada
- Department of Psychiatry, McGill University, Montreal, H3A 1A1, QC, Canada
| | - Taylor W Schmitz
- Department of Physiology & Pharmacology, Western Institute for Neuroscience, Western University, London, N6A 5C1, ON, Canada
| | - Gary R Turner
- Department of Psychology, York University, Toronto, M3J 1P3, ON, Canada
| | - R Nathan Spreng
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, QC, Canada.
- McConnell Brain Imaging Centre, McGill University, Montreal, H3A 2B4, QC, Canada.
- Douglas Mental Health University Institute-Research Center, Verdun, H4H 1R3, QC, Canada.
- Department of Psychiatry, McGill University, Montreal, H3A 1A1, QC, Canada.
| |
Collapse
|
4
|
Pierson SR, Kolling LJ, James TD, Pushpavathi SG, Marcinkiewcz CA. Serotonergic dysfunction may mediate the relationship between alcohol consumption and Alzheimer's disease. Pharmacol Res 2024; 203:107171. [PMID: 38599469 PMCID: PMC11088857 DOI: 10.1016/j.phrs.2024.107171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/14/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
The impact of Alzheimer's disease (AD) and its related dementias is rapidly expanding, and its mitigation remains an urgent social and technical challenge. To date there are no effective treatments or interventions for AD, but recent studies suggest that alcohol consumption is correlated with the risk of developing dementia. In this review, we synthesize data from preclinical, clinical, and epidemiological models to evaluate the combined role of alcohol consumption and serotonergic dysfunction in AD, underscoring the need for further research on this topic. We first discuss the limitations inherent to current data-collection methods, and how neuropsychiatric symptoms common among AD, alcohol use disorder, and serotonergic dysfunction may mask their co-occurrence. We additionally describe how excess alcohol consumption may accelerate the development of AD via direct effects on serotonergic function, and we explore the roles of neuroinflammation and proteostasis in mediating the relationship between serotonin, alcohol consumption, and AD. Lastly, we argue for a shift in current research to disentangle the pathogenic effects of alcohol on early-affected brainstem structures in AD.
Collapse
Affiliation(s)
- Samantha R Pierson
- Department of Neuroscience and Pharmacology, University of Iowa, United States
| | - Louis J Kolling
- Department of Neuroscience and Pharmacology, University of Iowa, United States
| | - Thomas D James
- Department of Neuroscience and Pharmacology, University of Iowa, United States
| | | | | |
Collapse
|
5
|
Beardmore R, Durkin M, Zayee-Mellick F, Lau LC, Nicoll JAR, Holmes C, Boche D. Changes in the locus coeruleus during the course of Alzheimer's disease and their relationship to cortical pathology. Neuropathol Appl Neurobiol 2024; 50:e12965. [PMID: 38374720 DOI: 10.1111/nan.12965] [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: 10/13/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 02/21/2024]
Abstract
AIMS In Alzheimer's disease (AD), the locus coeruleus (LC) undergoes early and extensive neuronal loss, preceded by abnormal intracellular tau aggregation, decades before the onset of clinical disease. Neuromelanin-sensitive MRI has been proposed as a method to image these changes during life. Surprisingly, human post-mortem studies have not examined how changes in LC during the course of the disease relate to cerebral pathology following the loss of the LC projection to the cortex. METHODS Immunohistochemistry was used to examine markers for 4G8 (pan-Aβ) and AT8 (ptau), LC integrity (neuromelanin, dopamine β-hydroxylase [DβH], tyrosine hydroxylase [TH]) and microglia (Iba1, CD68, HLA-DR) in the LC and related temporal lobe pathology of 59 post-mortem brains grouped by disease severity determined by Braak stage (0-II, III-IV and V-VI). The inflammatory environment was assessed using multiplex assays. RESULTS Changes in the LC with increasing Braak stage included increased neuronal loss (p < 0.001) and microglial Iba1 (p = 0.005) together with a reduction in neuromelanin (p < 0.001), DβH (p = 0.002) and TH (p = 0.041). Interestingly in LC, increased ptau and loss of neuromelanin were detected from Braak stage III-IV (p = 0.001). At Braak stage V/VI, the inflammatory environment was different in the LC vs TL, highlighting the anatomical heterogeneity of the inflammatory response. CONCLUSIONS Here, we report the first quantification of neuromelanin during the course of AD and its relationship to AD pathology and neuroinflammation in the TL. Our findings of neuromelanin loss early in AD and before the neuroinflammatory reaction support the use of neuromelanin-MRI as a sensitive technique to identify early changes in AD.
Collapse
Affiliation(s)
- Rebecca Beardmore
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Memory Assessment and Research Centre, Moorgreen Hospital, Southern Health Foundation Trust, Southampton, UK
| | - Matthew Durkin
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Faizan Zayee-Mellick
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Laurie C Lau
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, University of Southampton, Southampton, UK
| | - James A R Nicoll
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Department of Cellular Pathology, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Clive Holmes
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Memory Assessment and Research Centre, Moorgreen Hospital, Southern Health Foundation Trust, Southampton, UK
| | - Delphine Boche
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| |
Collapse
|
6
|
Sagar R, Zivko C, Xydia A, Weisman DC, Lyketsos CG, Mahairaki V. Generation and Characterization of a Human-Derived and Induced Pluripotent Stem Cell (iPSC) Line from an Alzheimer's Disease Patient with Neuropsychiatric Symptoms. Biomedicines 2023; 11:3313. [PMID: 38137534 PMCID: PMC10741135 DOI: 10.3390/biomedicines11123313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/01/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Agitation is one of the most eminent characteristics of neuropsychiatric symptoms (NPS) affecting people living with Alzheimer's and Dementia and has serious consequences for patients and caregivers. The current consensus is that agitation results, in part, from the disruption of ascending monoamine regulators of cortical circuits, especially the loss of serotonergic activity. It is believed that the first line of treatment for these conditions is selective serotonin reuptake inhibitors (SSRIs), but these are effective in only about 40% of patients. Person-specific biomarkers, for example, ones based on in vitro iPSC-derived models of serotonin activity, which predict who with Agitation responds to an SSRI, are a major clinical priority. Here, we report the generation of human-induced pluripotent stem cells (iPSCs) from a 74-year-old AD patient, the homozygous APOE ε4/ε4 carrier, who developed Agitation. His iPSCs were reprogrammed from peripheral blood mononuclear cells (PBMCs) using the transient expression of pluripotency genes. These display typical iPSC characteristics that are karyotypically normal and attain the capacity to differentiate into three germ layers. The newly patient-derived iPSC line offers a unique resource to investigate the underlying mechanisms associated with neuropsychiatric symptom progression in AD.
Collapse
Affiliation(s)
- Ram Sagar
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (R.S.); (C.Z.); (A.X.)
- The Richman Family Precision Medicine Center of Excellence in Alzheimer’s Disease, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
- The Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD 21287, USA
| | - Cristina Zivko
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (R.S.); (C.Z.); (A.X.)
- The Richman Family Precision Medicine Center of Excellence in Alzheimer’s Disease, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
- The Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD 21287, USA
| | - Ariadni Xydia
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (R.S.); (C.Z.); (A.X.)
- The Richman Family Precision Medicine Center of Excellence in Alzheimer’s Disease, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
- The Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD 21287, USA
| | - David C. Weisman
- Abington Neurologic Associates, Clinical Research Center, Abington, PA 19001, USA
| | - Constantine G. Lyketsos
- The Richman Family Precision Medicine Center of Excellence in Alzheimer’s Disease, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
- The Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD 21287, USA
| | - Vasiliki Mahairaki
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (R.S.); (C.Z.); (A.X.)
- The Richman Family Precision Medicine Center of Excellence in Alzheimer’s Disease, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
- The Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD 21287, USA
| |
Collapse
|
7
|
Modrego PJ, de Cerio LD, Lobo A. The Interface between Depression and Alzheimer's Disease. A Comprehensive Approach. Ann Indian Acad Neurol 2023; 26:315-325. [PMID: 37970263 PMCID: PMC10645209 DOI: 10.4103/aian.aian_326_23] [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: 04/14/2023] [Revised: 07/04/2023] [Accepted: 07/04/2023] [Indexed: 11/17/2023] Open
Abstract
Depression and Alzheimer's disease (AD) are frequent interacting diseases in the elderly with a negative impact on the quality of life of patients and caregivers. Late-life depression may be regarded either as an early symptom of AD or a risk factor for AD, depending on the context. This review was focused on the latest developments in the fields of the neurobiological basis and treatment of depression in AD. We found that some plausible hypotheses are emerging to correlate with depression in AD, such as neuroinflammation and dysimmune regulation. It seems that depression is not related to amyloid deposition, but this issue is not completely resolved. The response to antidepressants is controversial according to the evidence from 10 small double-blind randomized placebo-controlled clinical trials with antidepressants in AD patients with depression: four with sertraline, one with three arms (sertraline, mirtazapine, placebo), one with fluoxetine, one with imipramine, one with clomipramine, one with escitalopram, and one with vortioxetine. The total number of treated patients completing the trials was 638. The main criterion of a positive response was a reduction in the scores of clinical scales for depression of at least 50%. The weighted OR (odds ratio) was calculated with the method of Mantel-Haenszel: 1.29; 95% CI: 0.77-2.16. No significant differences were found compared with placebo. Antidepressants did not have a meaningful negative influence on cognition, which was measured with the mini-mental state examination (MMSE) in 18 clinical trials. Alternatives other than drugs are also discussed. Although there have been important advances in this field, pathophysiology and treatment deserve further research.
Collapse
Affiliation(s)
- Pedro J. Modrego
- Servicio de Neurologia, Hospital Miguel Servet de Zaragoza, Spain
| | | | - Antonio Lobo
- Department of Psychiatry, University of Zaragoza, Spain
| |
Collapse
|
8
|
Nageeb Hasan SM, Clarke CL, McManamon Strand TP, Bambico FR. Putative pathological mechanisms of late-life depression and Alzheimer's Disease. Brain Res 2023:148423. [PMID: 37244602 DOI: 10.1016/j.brainres.2023.148423] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by progressive impairment in cognition and memory. AD is accompanied by several neuropsychiatric symptoms, with depression being the most prominent. Although depression has long been known to be associated with AD, controversial findings from preclinical and clinical studies have obscured the precise nature of this association. However recent evidence suggests that depression could be a prodrome or harbinger of AD. Evidence indicates that the major central serotonergic nucleus-the dorsal raphe nucleus (DRN)-shows very early AD pathology: neurofibrillary tangles made of hyperphosphorylated tau protein and degenerated neurites. AD and depression share common pathophysiologies, including functional deficits of the serotonin (5-HT) system. 5-HT receptors have modulatory effects on the progression of AD pathology i.e., reduction in Aβ load, increased hyper-phosphorylation of tau, decreased oxidative stress etc. Moreover, preclinical models show a role for specific channelopathies that result in abnormal regional activational and neuroplasticity patterns. One of these concerns the pathological upregulation of the small conductance calcium-activated potassium (SK) channel in corticolimbic structure. This has also been observed in the DRN in both diseases. The SKC is a key regulator of cell excitability and long-term potentiation (LTP). SKC over-expression is positively correlated with aging and cognitive decline, and is evident in AD. Pharmacological blockade of SKCs has been reported to reverse symptoms of depression and AD. Thus, aberrant SKC functioning could be related to depression pathophysiology and diverts its late-life progression towards the development of AD. We summarize findings from preclinical and clinical studies suggesting a molecular linkage between depression and AD pathology. We also provide a rationale for considering SKCs as a novel pharmacological target for the treatment of AD-associated symptoms.
Collapse
Affiliation(s)
- S M Nageeb Hasan
- Department of Psychology, Memorial University of Newfoundland and Labrador, Newfoundland and Labrador, A1B3Xs, Canada.
| | - Courtney Leigh Clarke
- Department of Psychology, Memorial University of Newfoundland and Labrador, Newfoundland and Labrador, A1B3Xs, Canada
| | | | - Francis Rodriguez Bambico
- Department of Psychology, Memorial University of Newfoundland and Labrador, Newfoundland and Labrador, A1B3Xs, Canada; Behavioural Neurobiology Laboratory, Centre for Addiction and Mental Health, Toronto, ON, M5T1R8, Canada
| |
Collapse
|
9
|
Ehrenberg AJ, Kelberman MA, Liu KY, Dahl MJ, Weinshenker D, Falgàs N, Dutt S, Mather M, Ludwig M, Betts MJ, Winer JR, Teipel S, Weigand AJ, Eschenko O, Hämmerer D, Leiman M, Counts SE, Shine JM, Robertson IH, Levey AI, Lancini E, Son G, Schneider C, Egroo MV, Liguori C, Wang Q, Vazey EM, Rodriguez-Porcel F, Haag L, Bondi MW, Vanneste S, Freeze WM, Yi YJ, Maldinov M, Gatchel J, Satpati A, Babiloni C, Kremen WS, Howard R, Jacobs HIL, Grinberg LT. Priorities for research on neuromodulatory subcortical systems in Alzheimer's disease: Position paper from the NSS PIA of ISTAART. Alzheimers Dement 2023; 19:2182-2196. [PMID: 36642985 PMCID: PMC10182252 DOI: 10.1002/alz.12937] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/08/2022] [Accepted: 12/19/2022] [Indexed: 01/17/2023]
Abstract
The neuromodulatory subcortical system (NSS) nuclei are critical hubs for survival, hedonic tone, and homeostasis. Tau-associated NSS degeneration occurs early in Alzheimer's disease (AD) pathogenesis, long before the emergence of pathognomonic memory dysfunction and cortical lesions. Accumulating evidence supports the role of NSS dysfunction and degeneration in the behavioral and neuropsychiatric manifestations featured early in AD. Experimental studies even suggest that AD-associated NSS degeneration drives brain neuroinflammatory status and contributes to disease progression, including the exacerbation of cortical lesions. Given the important pathophysiologic and etiologic roles that involve the NSS in early AD stages, there is an urgent need to expand our understanding of the mechanisms underlying NSS vulnerability and more precisely detail the clinical progression of NSS changes in AD. Here, the NSS Professional Interest Area of the International Society to Advance Alzheimer's Research and Treatment highlights knowledge gaps about NSS within AD and provides recommendations for priorities specific to clinical research, biomarker development, modeling, and intervention. HIGHLIGHTS: Neuromodulatory nuclei degenerate in early Alzheimer's disease pathological stages. Alzheimer's pathophysiology is exacerbated by neuromodulatory nuclei degeneration. Neuromodulatory nuclei degeneration drives neuropsychiatric symptoms in dementia. Biomarkers of neuromodulatory integrity would be value-creating for dementia care. Neuromodulatory nuclei present strategic prospects for disease-modifying therapies.
Collapse
Affiliation(s)
- Alexander J Ehrenberg
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, California, USA
| | - Michael A Kelberman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Kathy Y Liu
- Division of Psychiatry, University College London, London, UK
| | - Martin J Dahl
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
- Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Neus Falgàs
- Alzheimer's Disease and Other Cognitive Disorders Unit, Neurology Service, Hospital Clínic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain
- Global Brain Health Institute, University of California, San Francisco, San Francisco, California, USA
| | - Shubir Dutt
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
- Department of Psychology, University of Southern California, Los Angeles, California, USA
| | - Mara Mather
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
- Department of Psychology, University of Southern California, Los Angeles, California, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Mareike Ludwig
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, University of Magdeburg, Magdeburg, Germany
| | - Matthew J Betts
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, University of Magdeburg, Magdeburg, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Joseph R Winer
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Stefan Teipel
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Rostock/Greifswald, Rostock, Germany
- Department of Psychosomatic Medicine, University Medicine Rostock, Rostock, Germany
| | - Alexandra J Weigand
- San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California, USA
| | - Oxana Eschenko
- Department of Computational Neuroscience, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany
| | - Dorothea Hämmerer
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
- Department of Psychology, University of Innsbruck, Innsbruck, Austria
- Institute of Cognitive Neuroscience, University College London, London, UK
| | - Marina Leiman
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Scott E Counts
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, Michigan, USA
- Department of Family Medicine, Michigan State University, Grand Rapids, Michigan, USA
- Michigan Alzheimer's Disease Research Center, Ann Arbor, Michigan, USA
| | - James M Shine
- Brain and Mind Center, The University of Sydney, Sydney, Australia
| | - Ian H Robertson
- Global Brain Health Institute, Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Allan I Levey
- Goizueta Alzheimer's Disease Research Center, Emory University, Atlanta, Georgia, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
- Goizueta Institute, Emory University, Atlanta, Georgia, USA
| | - Elisa Lancini
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Gowoon Son
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
| | - Christoph Schneider
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Maxime Van Egroo
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Faculty of Health, Medicine, and Life Sciences, School for Mental Health and Neuroscience, Alzheimer Centre Limburg, Maastricht University, Maastricht, the Netherlands
| | - Claudio Liguori
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
- Neurology Unit, University Hospital of Rome Tor Vergata, Rome, Italy
| | - Qin Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Agusta University, Agusta, Georgia, USA
| | - Elena M Vazey
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | | | - Lena Haag
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Mark W Bondi
- Department of Psychiatry, University of California, San Diego, La Jolla, California, USA
- Psychology Service, VA San Diego Healthcare System, San Diego, California, USA
| | - Sven Vanneste
- Global Brain Health Institute, Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- School of Psychology, Trinity College Dublin, Dublin, Ireland
- Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Whitney M Freeze
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Neuropsychology and Psychiatry, Maastricht University, Maastricht, the Netherlands
| | - Yeo-Jin Yi
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Mihovil Maldinov
- Department of Psychiatry and Psychotherapy, University of Rostock, Rostock, Germany
| | - Jennifer Gatchel
- Division of Geriatric Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Abhijit Satpati
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
| | - Claudio Babiloni
- Department of Physiology and Pharmacology "V. Erspamer,", Sapienza University of Rome, Rome, Italy
- Hospital San Raffaele Cassino, Cassino, Italy
| | - William S Kremen
- Center for Behavior Genetics of Aging, University of California, San Diego, La Jolla, California, USA
| | - Robert Howard
- Division of Psychiatry, University College London, London, UK
| | - Heidi I L Jacobs
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Faculty of Health, Medicine, and Life Sciences, School for Mental Health and Neuroscience, Alzheimer Centre Limburg, Maastricht University, Maastricht, the Netherlands
| | - Lea T Grinberg
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
- Global Brain Health Institute, University of California, San Francisco, San Francisco, California, USA
- Department of Pathology, University of California, San Francisco, San Francisco, California, USA
- Department of Pathology, University of São Paulo Medical School, São Paulo, Brazil
| |
Collapse
|
10
|
Khan KM, Balasubramanian N, Gaudencio G, Wang R, Selvakumar GP, Kolling L, Pierson S, Tadinada SM, Abel T, Hefti M, Marcinkiewcz CA. Human tau-overexpressing mice recapitulate brainstem involvement and neuropsychiatric features of early Alzheimer's disease. Acta Neuropathol Commun 2023; 11:57. [PMID: 37009893 PMCID: PMC10069039 DOI: 10.1186/s40478-023-01546-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/07/2023] [Indexed: 04/04/2023] Open
Abstract
Alzheimer's disease (AD) poses an ever-increasing public health concern as the population ages, affecting more than 6 million Americans. AD patients present with mood and sleep changes in the prodromal stages that may be partly driven by loss of monoaminergic neurons in the brainstem, but a causal relationship has not been firmly established. This is due in part to a dearth of animal models that recapitulate early AD neuropathology and symptoms. The goal of the present study was to evaluate depressive and anxiety-like behaviors in a mouse model of AD that overexpresses human wild-type tau (htau) prior to the onset of cognitive impairments and assess these behavior changes in relationship to tau pathology, neuroinflammation, and monoaminergic dysregulation in the dorsal raphe nucleus (DRN) and locus coeruleus (LC). We observed depressive-like behaviors at 4 months in both sexes and hyperlocomotion in male htau mice. Deficits in social interaction persisted at 6 months and were accompanied by an increase in anxiety-like behavior in males. The behavioral changes at 4 months coincided with a lower density of serotonergic (5-HT) neurons, downregulation of 5-HT markers, reduced excitability of 5-HT neurons, and hyperphosphorylated tau in the DRN. Inflammatory markers were also upregulated in the DRN along with protein kinases and transglutaminase 2, which may promote tau phosphorylation and aggregation. Loss of 5-HT innervation to the entorhinal cortex and dentate gyrus of the hippocampus was also observed and may have contributed to depressive-like behaviors. There was also reduced expression of noradrenergic markers in the LC along with elevated phospho-tau expression, but this did not translate to a functional change in neuronal excitability. In total, these results suggest that tau pathology in brainstem monoaminergic nuclei and the resulting loss of serotonergic and/or noradrenergic drive may underpin depressive- and anxiety-like behaviors in the early stages of AD.
Collapse
Affiliation(s)
- Kanza M Khan
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
- Psychological Sciences Department, Daemen University, Amherst, NY, 14226, USA
| | - Nagalakshmi Balasubramanian
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | - Gabriel Gaudencio
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | - Ruixiang Wang
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | | | - Louis Kolling
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | - Samantha Pierson
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | - Satya M Tadinada
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA
| | - Marco Hefti
- Department of Pathology, University of Iowa, Iowa City, IA, 52242, USA
| | - Catherine A Marcinkiewcz
- Department of Neuroscience and Pharmacology, University of Iowa, 2-430 Bowen Science Building, Iowa City, IA, 52242, USA.
| |
Collapse
|
11
|
Lazarova MI, Tancheva LP, Tasheva KN, Denev PN, Uzunova DN, Stefanova MO, Tsvetanova ER, Georgieva AP, Kalfin RE. Effects of Sideritis scardica Extract on Scopolamine-Induced Learning and Memory Impairment in Mice. J Alzheimers Dis 2023; 92:1289-1302. [PMID: 36872784 DOI: 10.3233/jad-230017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
BACKGROUND The neurodegenerative process in Alzheimer's disease, one of the most common types of dementia worldwide, mostly affects the cholinergic neurotransmitter system and, to a lesser extent, the monoaminergic one. The antioxidant acetylcholinesterase (AChE) and triple monoamine reuptake inhibitory activity of Sideritis scardica (S. scardica) and other Sideritis species has already been reported. OBJECTIVE To investigate the effects of S. scardica water extracts on the learning and memory processes, anxiety-like behavior, and locomotor activities in scopolamine (Sco)-induced dementia in mice. METHODS Male Albino IRC mice were used. The plant extract was administered for 11 consecutive days in the presence or absence of Sco (1 mg/kg, i.p). The behavioural performance of the animals was evaluated by passive avoidance, T-maze, and hole-board tests. The effects of extract on AChE activity, brain noradrenalin (NA), and serotonin (Sero) content, and antioxidant status were also monitored. RESULTS Our experimental data revealed that the S. scardica water extract caused a reduction in degree of memory impairment and anxiety-like behaviour in mice with scopolamine-induced dementia. The extract did not affect changed by the Sco AChE activity but impact reduced brain NA and Sero levels and demonstrated moderate antioxidant activity. In healthy mice we did not confirm the presence of anxiolytic-like and AChE inhibitory effects of the S. scardica water extract. The extract did not change the control Sero brain levels and reduce those of NA. CONCLUSION S. scardica water extract demonstrated memory preserving effect in mice with scopolamine-induced dementia and deserve further attention.
Collapse
Affiliation(s)
- Maria I Lazarova
- Institute of Neurobiology, Bulgarian Academy of Science, Sofia, Bulgaria
| | - Lyubka P Tancheva
- Institute of Neurobiology, Bulgarian Academy of Science, Sofia, Bulgaria.,Weston Professor of Weizmann Institute of Science, Israel
| | - Krasimira N Tasheva
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Petko N Denev
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Laboratory of Biologically Active Substances - Plovdiv, Bulgaria
| | - Diamara N Uzunova
- Institute of Neurobiology, Bulgarian Academy of Science, Sofia, Bulgaria
| | | | - Elina R Tsvetanova
- Institute of Neurobiology, Bulgarian Academy of Science, Sofia, Bulgaria
| | - Almira P Georgieva
- Institute of Neurobiology, Bulgarian Academy of Science, Sofia, Bulgaria
| | - Reni E Kalfin
- Institute of Neurobiology, Bulgarian Academy of Science, Sofia, Bulgaria.,Department of Healthcare, South-West University "Neofit Rilski", Blagoevgrad, Bulgaria
| |
Collapse
|
12
|
Downs AM, Catavero CM, Kasten MR, McElligott ZA. Tauopathy and alcohol consumption interact to alter locus coeruleus excitatory transmission and excitability in male and female mice. Alcohol 2023; 107:97-107. [PMID: 36150608 DOI: 10.1016/j.alcohol.2022.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/22/2022] [Accepted: 08/29/2022] [Indexed: 12/23/2022]
Abstract
Alcohol use disorder is a major public health concern in the United States. Recent work has suggested a link between chronic alcohol consumption and the development of tauopathy disorders, such as Alzheimer's disease and frontotemporal dementia. However, relatively little work has investigated changes in neural circuitry involved in both tauopathy disorders and alcohol use disorder. The locus coeruleus (LC) is the major noradrenergic nucleus in the brain and is one of the earliest sites to be affected by tau lesions. The LC is also implicated in the rewarding effects of ethanol and alcohol withdrawal. In this study we assessed effects of long-term ethanol consumption and tauopathy on the physiology of LC neurons. Male and female P301S mice, a humanized transgenic mouse model of tauopathy, underwent 16 weeks of intermittent access to 20% ethanol from 3 to 7 months of age. We observed higher total alcohol consumption in female mice regardless of genotype. Male P301S mice consumed more ethanol and had a greater preference for ethanol than wild-type (WT) males. At the end of the drinking study, LC function was assessed using ex vivo whole cell electrophysiology. We found significant changes in excitatory inputs to the LC due to both ethanol and genotype. We found significantly increased excitability of the LC due to ethanol with greater effects in female P301S mice than in female WT mice. Our study identifies significant changes in the LC due to interactions between tauopathy and long-term ethanol use. These findings could have important implications regarding LC activity and changes in behavior due to both ethanol- and tauopathy-related dementia.
Collapse
Affiliation(s)
- Anthony M Downs
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Christina M Catavero
- Graduate Program in Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Michael R Kasten
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Zoé A McElligott
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
| |
Collapse
|
13
|
Brash DE, Goncalves LCP. Chemiexcitation: Mammalian Photochemistry in the Dark †. Photochem Photobiol 2023; 99:251-276. [PMID: 36681894 PMCID: PMC10065968 DOI: 10.1111/php.13781] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 01/18/2023] [Indexed: 01/23/2023]
Abstract
Light is one way to excite an electron in biology. Another is chemiexcitation, birthing a reaction product in an electronically excited state rather than exciting from the ground state. Chemiexcited molecules, as in bioluminescence, can release more energy than ATP. Excited states also allow bond rearrangements forbidden in ground states. Molecules with low-lying unoccupied orbitals, abundant in biology, are particularly susceptible. In mammals, chemiexcitation was discovered to transfer energy from excited melanin, neurotransmitters, or hormones to DNA, creating the lethal and carcinogenic cyclobutane pyrimidine dimer. That process was initiated by nitric oxide and superoxide, radicals triggered by ultraviolet light or inflammation. Several poorly understood chronic diseases share two properties: inflammation generates those radicals across the tissue, and cells that die are those containing melanin or neuromelanin. Chemiexcitation may therefore be a pathogenic event in noise- and drug-induced deafness, Parkinson's disease, and Alzheimer's; it may prevent macular degeneration early in life but turn pathogenic later. Beneficial evolutionary selection for excitable biomolecules may thus have conferred an Achilles heel. This review of recent findings on chemiexcitation in mammalian cells also describes the underlying physics, biochemistry, and potential pathogenesis, with the goal of making this interdisciplinary phenomenon accessible to researchers within each field.
Collapse
Affiliation(s)
- Douglas E. Brash
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA
- Yale Cancer Center, Yale School of Medicine, New Haven, CT 06520-8028, USA
| | - Leticia C. P. Goncalves
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA
- Institut de Chimie de Nice CNRS UMR7272, Université Côte d’Azur, 28 Avenue Valrose 06108 Nice, France
| |
Collapse
|
14
|
Anxiety and depression in Alzheimer's disease: a systematic review of pathogenetic mechanisms and relation to cognitive decline. Neurol Sci 2022; 43:4107-4124. [PMID: 35461471 PMCID: PMC9213384 DOI: 10.1007/s10072-022-06068-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/06/2022] [Indexed: 12/13/2022]
Abstract
Objectives To explore the pathogenetic hypothesis provided to explain the comorbidity of anxious and depressive symptomatology and AD and to assess the association between anxious and depressive symptoms and the AD-related cognitive impairment. Methods In October 2020 and March 2021, PsycINFO, Embase, Ovid, and CINAHL were searched for peer-reviewed original articles investigating anxiety and/or depression in AD. Results A total of 14,760 studies were identified and 34 papers on AD patients were included in the review. Suggested biological causes of depression and anxiety in AD include higher strychnine-sensitive glycine receptor (GlyRS) functioning and selective reduction of N-methyl-d-aspartate (NMDA) receptor NR2A density, cortical and limbic atrophy, lower resting cortical metabolism, lower CSF Aβ42 and higher t-tau and p-tau levels, and neuritic plaques. At the same time, dysthymia arises in the early stages of AD as an emotional reaction to the progressive cognitive decline and can cause it; anxiety can appear as an initial compensating behaviour; and depression might be related to AD awareness and loss of functional abilities. Affective symptoms and the expression of the depressive symptoms tend to reduce as AD progresses. Conclusion The neurodegeneration of areas and circuits dealing with emotions can elicit anxiety and depression in AD. In the early stages of the disease, anxiety and depression could arise as a psychological reaction to AD and due to coping difficulties. In late AD stages, the cognitive impairment reduces the emotional responses and their expression. Anxiety and depression are more intense in early-onset AD, due to the major impact of AD on the individual. Supplementary Information The online version contains supplementary material available at 10.1007/s10072-022-06068-x.
Collapse
|
15
|
Behl T, Kaur I, Sehgal A, Singh S, Makeen HA, Albratty M, Alhazmi HA, Bhatia S, Bungau S. The Locus Coeruleus - Noradrenaline system: Looking into Alzheimer's therapeutics with rose coloured glasses. Biomed Pharmacother 2022; 151:113179. [PMID: 35676784 DOI: 10.1016/j.biopha.2022.113179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/17/2022] [Accepted: 05/22/2022] [Indexed: 11/16/2022] Open
Abstract
Owing to the challenging ethos of global healthcare system, the Alzheimer's Disease (AD) researchers are consistently striving for a suitable target for disease amelioration. Besides the neurotransmitter release by neurons, the cells release tau proteins and amyloid peptides, within the extracellular vacancies, aggregating into tangles and plaques (AD pathological hallmarks). During neuro-stimulation, release of neuromodulator noradrenaline (NA), contained in the locus coeruleus (LC), exerts a significant impact on the neurons and microglia. The production of amyloid-β (Aβ) and hyperphosphorylation of tau proteins are affected by the α2A and β adrenoreceptors, parallel to influencing their clearance. The manuscript entails a detailed understanding of the LC-NA system, as a possible avenue in AD management. The authors provide a comprehensive data on AD pathology and its link with LC neuroanatomical projections, followed by the pathogenic implications of LC-NA system in AD. The data also integrates numerous studies from online databases, evidently supporting the loss of the system integrity in AD patients, and the impact of the sympathetic system on specific AD hallmarks. Thus, the objective of this review is to compile a wide compendium of studies, for the convenience of the neuro-researchers, aiding in the establishment of a suitable therapeutic regimen for AD treatment.
Collapse
Affiliation(s)
- Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, India; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania.
| | - Ishnoor Kaur
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, India; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Aayush Sehgal
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, India; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Sukhbir Singh
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, India; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Hafiz A Makeen
- Pharmacy Practice Research Unit, Clinical Pharmacy Department, College of Pharmacy, Jazan University, Jazan, Saudi Arabia; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Mohammed Albratty
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jazan University, Jazan, Saudi Arabia; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Hassan A Alhazmi
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jazan University, Jazan, Saudi Arabia; Substance Abuse and Toxicology Research Centre, Jazan University, Jazan, Saudi Arabia; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Saurabh Bhatia
- Natural & Medical Sciences Research Centre, University of Nizwa, Birkat Al Mauz, Nizwa, Oman; School of Health Science, University of Petroleum and Energy Studies, Dehradun, India; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania; Doctoral School of Biomedical Sciences, University of Oradea, Oradea, Romania.
| |
Collapse
|
16
|
Association between Ultraviolet B Exposure Levels and Depression in Taiwanese Adults: A Nested Case-Control Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19116846. [PMID: 35682430 PMCID: PMC9180491 DOI: 10.3390/ijerph19116846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/19/2022] [Accepted: 05/30/2022] [Indexed: 02/06/2023]
Abstract
Depression is a common mental disorder that affects more than 264 million people worldwide. Anxiety, diabetes, Alzheimer’s disease, myocardial infarction, and cancer, among other disorders, are known to increase the risk of depression. Exposure to ultraviolet B (UVB) can cause human serotonin levels to increase. The vitamin D pathway is one mechanism through which ultraviolet light absorbed through the skin can affect mood; however, UVB exposure is known to increase the risk of cancer. In this study, we explored the effects of prolonged exposure to UVB on depression. Data were retrieved from the Taiwan National Health Insurance Research Database for 2008 to 2013. Each patient with depression was matched 1:4 with a comparison patient by sex and age (±5 years); thus, the study included 23,579 patients with depression and 94,316 healthy controls for comparison. The patients had been exposed to UVB for at least 1 year to observe the cumulative effect of UVB exposure. Based on the World Health Organization UV index, we divided the observation period data into five UV levels: low, moderate, high, very high, and extreme. A multivariate Poisson regression model was used to assess the risk of depression according to UVB exposure level, adjusting for sex, age, income, urbanization level, month, and comorbidities. The results revealed that the incidence rate ratio (IRR) for patients with depression was 0.889 for moderate levels (95% CI 0.835–0.947), 1.134 for high levels (95% CI: 1.022–1.260), 1.711 for very high levels (95% CI: 1.505–1.945), and 2.785 for extreme levels (95% CI: 2.439–3.180) when compared to low levels. Moderate levels of UVB lowered the risk of depression, while high levels of UVB gradually increased the risk. We propose that UVB at normal concentrations can effectively improve depression. However, exposure to high concentrations of UVB damage DNA results in physical diseases such as skin cancer, which increase the risk of depression.
Collapse
|
17
|
Geriatric Depression and Inappropriate Medication: Benefits of Interprofessional Team Cooperation in Nursing Homes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182312438. [PMID: 34886164 PMCID: PMC8657238 DOI: 10.3390/ijerph182312438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/18/2021] [Accepted: 11/20/2021] [Indexed: 11/26/2022]
Abstract
An investigation of inappropriate medication use in treatment of depressivity in institutionalized older adults, based on a nurse-led evaluation of functional status and depressive symptoms in nursing home residents. Methods: A cross-sectional multicenter study was performed using records from 1087 residents cared for in fifteen nursing homes (NHs) in the Czech Republic. Inclusion criteria were being a permanent resident of one of the facilities, being 60 years of age or older, having a Geriatric Depression Scale score of 6 or more, and having a Mini Mental State examination score 10 or more. The final sample for analysis included 317 depressed NH residents. Results: 52 percent of NH residents with depressivity had no antidepressant treatment. Benzodiazepines were the only medication in 16 percent of depressed residents, and were added to antidepressant treatment in 18 percent of residents. Benzodiazepine users had significantly higher GDS scores compared to non-users (p = 0.007). Conclusion: More than half of depressed NH residents remained without antidepressant treatment. Residents inappropriately treated with benzodiazepines were more depressed than residents treated with antidepressants only, or even not treated at all. Cooperation of the interprofessional team in the screening of depressive symptoms has the potential to improve the quality of care.
Collapse
|
18
|
Muñiz R, López-Alvarez J, Agüera-Ortiz L, Perea L, Olazarán J. Syndrome-Based Prescription to Optimize Psychotropics: Are CHROME Criteria a Game Changer? Front Psychiatry 2021; 12:662228. [PMID: 33967863 PMCID: PMC8101684 DOI: 10.3389/fpsyt.2021.662228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
A variety of medical and social factors have contributed over the last decades to the overuse of psychotropic drugs in people with dementia. One social factor is probably the frequent failure to provide adequate person-centered care, be it in the community or in institutional settings. This unfortunate reality has been reacted upon with numerous guidelines to reduce prescriptions of the most dangerous drugs (e.g., neuroleptics). Each psychotropic drug prescription can in principle be assessed around three dimensions: (a) adequate, (b) inadequate, and (c) chemical restraint. The CHemical Restraints avOidance MEthodology (CHROME) defined chemical restraint as any prescription based on organizational convenience, rather than justified with medical diagnosis. Two validation studies revealed that one of the main medical reasons of over- and miss-prescriptions was symptom-based prescription. By switching to syndrome-based prescription, a large proportion of drugs could be de-prescribed and some re-adjusted or kept. Paucity of research and weakness of data are not conclusive about the adequacy of specific drugs for the myriad of cases presented by patients with dementia and comorbid conditions. Clinical practice, however, leads us to believe that even under optimal care conditions, psychotropics might still contribute to quality of life if based on an adequate diagnosis. This article explains the rationale that underlies a syndromic approach aimed at optimizing psychotropic treatment in people with dementia whose significant suffering derives from their thought, affective, or behavioral problems. The results of previous validation studies of this new methodology will be discussed and conclusions for future results will be drawn.
Collapse
Affiliation(s)
| | - Jorge López-Alvarez
- Maria Wolff Foundation, Madrid, Spain
- Servicio de Psiquiatría, Instituto de Investigación i+12, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Luis Agüera-Ortiz
- Servicio de Psiquiatría, Instituto de Investigación i+12, Hospital Universitario 12 de Octubre, Madrid, Spain
- CIBERSAM, Madrid, Spain
| | - Luis Perea
- Albertia Servicios Sociosanitarios, Madrid, Spain
| | - Javier Olazarán
- Maria Wolff Foundation, Madrid, Spain
- Memory Disorders Clinic, HM Hospitals, Madrid, Spain
- Neurology Service, University Hospital Gregorio Marañón, Madrid, Spain
| |
Collapse
|
19
|
Babić Leko M, Nikolac Perković M, Klepac N, Švob Štrac D, Borovečki F, Pivac N, Hof PR, Šimić G. Relationships of Cerebrospinal Fluid Alzheimer's Disease Biomarkers and COMT, DBH, and MAOB Single Nucleotide Polymorphisms. J Alzheimers Dis 2021; 73:135-145. [PMID: 31771069 PMCID: PMC7029364 DOI: 10.3233/jad-190991] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The noradrenergic and dopaminergic systems are affected in Alzheimer’s disease (AD). Polymorphisms in genes encoding enzymes and proteins that are components of these systems can affect products of transcription and translation and lead to altered enzymatic activity and alterations in overall dopamine and noradrenaline levels. Catechol-O-methyltransferase (COMT) and monoamine oxidase B (MAOB) are the enzymes that regulate degradation of dopamine, while dopamine β-hydroxylase (DBH) is involved in synthesis of noradrenaline. COMT Val158Met (rs4680), DBH rs1611115 (also called –1021C/T or –970C/T), and MAOB rs1799836 (also called A644G) polymorphisms have been previously associated with AD. We assessed whether these polymorphisms are associated with cerebrospinal fluid (CSF) AD biomarkers including total tau (t-tau), phosphorylated tau proteins (p-tau181, p-tau199, and p-tau231), amyloid-β42 (Aβ42), and visinin-like protein 1 (VILIP-1) to test possible relationships of specific genotypes and pathological levels of CSF AD biomarkers. The study included 233 subjects: 115 AD, 53 mild cognitive impairment, 54 subjects with other primary causes of dementia, and 11 healthy controls. Significant decrease in Aβ42 levels was found in patients with GG compared to AG COMT Val158Met genotype, while t-tau and p-tau181 levels were increased in patients with AA compared to AG COMT Val158Met genotype. Aβ42 levels were also decreased in carriers of A allele in MAO-B rs1799836 polymorphism, while p-tau181 levels were increased in carriers of T allele in DBH rs1611115 polymorphism. These results indicate that COMT Val158Met, DBH rs1611115, and MAOB rs1799836 polymorphisms deserve further investigation as genetic markers of AD.
Collapse
Affiliation(s)
- Mirjana Babić Leko
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | | | - Nataša Klepac
- Department of Neurology, University Hospital Centre Zagreb, Zagreb, Croatia
| | | | - Fran Borovečki
- Department of Neurology, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Nela Pivac
- Department of Molecular Medicine, Institute Ruđer Bošković, Zagreb, Croatia
| | - Patrick R Hof
- Nash Family Department of Neuroscience, Friedman Brain Institute, and Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Goran Šimić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| |
Collapse
|
20
|
Khatri DK, Kadbhane A, Patel M, Nene S, Atmakuri S, Srivastava S, Singh SB. Gauging the role and impact of drug interactions and repurposing in neurodegenerative disorders. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2021; 2:100022. [PMID: 34909657 PMCID: PMC8663985 DOI: 10.1016/j.crphar.2021.100022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/23/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neurodegenerative diseases (ND) are of vast origin which are characterized by gradual progressive loss of neurons in the brain region. ND can be classified according to the clinical symptoms present (e.g. Cognitive decline, hyperkinetic, and hypokinetic movements disorder) or by the pathological protein deposited (e.g., Amyloid, tau, Alpha-synuclein, TDP-43). Alzheimer's disease preceded by Parkinson's is the most prevalent form of ND world-wide. Multiple factors like aging, genetic mutations, environmental factors, gut microbiota, blood-brain barrier microvascular complication, etc. may increase the predisposition towards ND. Genetic mutation is a major contributor in increasing the susceptibility towards ND, the concept of one disease-one gene is obsolete and now multiple genes are considered to be involved in causing one particular disease. Also, the involvement of multiple pathological mechanisms like oxidative stress, neuroinflammation, mitochondrial dysfunction, etc. contributes to the complexity and makes them difficult to be treated by traditional mono-targeted ligands. In this aspect, the Poly-pharmacological drug approach which targets multiple pathological pathways at the same time provides the best way to treat such complex networked CNS diseases. In this review, we have provided an overview of ND and their pathological origin, along with a brief description of various genes associated with multiple diseases like Alzheimer's, Parkinson's, Multiple sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS), Huntington's and a comprehensive detail about the Poly-pharmacology approach (MTDLs and Fixed-dose combinations) along with their merits over the traditional single-targeted drug is provided. This review also provides insights into current repurposing strategies along with its regulatory considerations.
Collapse
Affiliation(s)
- Dharmendra Kumar Khatri
- Corresponding authors. Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India.
| | | | | | | | | | | | - Shashi Bala Singh
- Corresponding authors. Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India.
| |
Collapse
|
21
|
Bekdash RA. The Cholinergic System, the Adrenergic System and the Neuropathology of Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22031273. [PMID: 33525357 PMCID: PMC7865740 DOI: 10.3390/ijms22031273] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/23/2021] [Accepted: 01/25/2021] [Indexed: 12/16/2022] Open
Abstract
Neurodegenerative diseases are a major public health problem worldwide with a wide spectrum of symptoms and physiological effects. It has been long reported that the dysregulation of the cholinergic system and the adrenergic system are linked to the etiology of Alzheimer’s disease. Cholinergic neurons are widely distributed in brain regions that play a role in cognitive functions and normal cholinergic signaling related to learning and memory is dependent on acetylcholine. The Locus Coeruleus norepinephrine (LC-NE) is the main noradrenergic nucleus that projects and supplies norepinephrine to different brain regions. Norepinephrine has been shown to be neuroprotective against neurodegeneration and plays a role in behavior and cognition. Cholinergic and adrenergic signaling are dysregulated in Alzheimer’s disease. The degeneration of cholinergic neurons in nucleus basalis of Meynert in the basal forebrain and the degeneration of LC-NE neurons were reported in Alzheimer’s disease. The aim of this review is to describe current literature on the role of the cholinergic system and the adrenergic system (LC-NE) in the pathology of Alzheimer’s disease and potential therapeutic implications.
Collapse
Affiliation(s)
- Rola A Bekdash
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA
| |
Collapse
|
22
|
Beardmore R, Hou R, Darekar A, Holmes C, Boche D. The Locus Coeruleus in Aging and Alzheimer's Disease: A Postmortem and Brain Imaging Review. J Alzheimers Dis 2021; 83:5-22. [PMID: 34219717 PMCID: PMC8461706 DOI: 10.3233/jad-210191] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2021] [Indexed: 12/21/2022]
Abstract
The locus coeruleus (LC), a tiny nucleus in the brainstem and the principal site of noradrenaline synthesis, has a major role in regulating autonomic function, arousal, attention, and neuroinflammation. LC dysfunction has been linked to a range of disorders; however particular interest is given to the role it plays in Alzheimer's disease (AD). The LC undergoes significant neuronal loss in AD, thought to occur early in the disease process. While neuronal loss in the LC has also been suggested to occur in aging, this relationship is less clear as the findings have been contradictory. LC density has been suggested to be indicative of cognitive reserve and the evidence for these claims will be discussed. Recent imaging techniques allowing visualization of the LC in vivo using neuromelanin-sensitive MRI are developing our understanding of the role of LC in aging and AD. Tau pathology within the LC is evident at an early age in most individuals; however, the relationship between tau accumulation and neuronal loss and why some individuals then develop AD is not understood. Neuromelanin pigment accumulates within LC cells with age and is proposed to be toxic and inflammatory when released into the extracellular environment. This review will explore our current knowledge of the LC changes in both aging and AD from postmortem, imaging, and experimental studies. We will discuss the reasons behind the susceptibility of the LC to neuronal loss, with a focus on the role of extracellular neuromelanin and neuroinflammation caused by the dysfunction of the LC-noradrenaline pathway.
Collapse
Affiliation(s)
- Rebecca Beardmore
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Memory Assessment and Research Centre, Moorgreen Hospital, Southern Health Foundation Trust, Southampton, UK
| | - Ruihua Hou
- Clinical and Experimental Sciences, Department of Psychiatry, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Angela Darekar
- Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Clive Holmes
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Memory Assessment and Research Centre, Moorgreen Hospital, Southern Health Foundation Trust, Southampton, UK
| | - Delphine Boche
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| |
Collapse
|
23
|
Ohm DT, Peterson C, Lobrovich R, Cousins KAQ, Gibbons GS, McMillan CT, Wolk DA, Van Deerlin V, Elman L, Spindler M, Deik A, Siderowf A, Trojanowski JQ, Lee EB, Grossman M, Irwin DJ. Degeneration of the locus coeruleus is a common feature of tauopathies and distinct from TDP-43 proteinopathies in the frontotemporal lobar degeneration spectrum. Acta Neuropathol 2020; 140:675-693. [PMID: 32804255 DOI: 10.1007/s00401-020-02210-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
Neurodegeneration of the locus coeruleus (LC) in age-related neurodegenerative diseases such as Alzheimer's disease (AD) is well documented. However, detailed studies of LC neurodegeneration in the full spectrum of frontotemporal lobar degeneration (FTLD) proteinopathies comparing tauopathies (FTLD-tau) to TDP-43 proteinopathies (FTLD-TDP) are lacking. Here, we tested the hypothesis that there is greater LC neuropathology and neurodegeneration in FTLD-tau compared to FTLD-TDP. We examined 280 patients including FTLD-tau (n = 94), FTLD-TDP (n = 135), and two reference groups: clinical/pathological AD (n = 32) and healthy controls (HC, n = 19). Adjacent sections of pons tissue containing the LC were immunostained for phosphorylated TDP-43 (1D3-p409/410), hyperphosphorylated tau (PHF-1), and tyrosine hydroxylase (TH) to examine neuromelanin-containing noradrenergic neurons. Blinded to clinical and pathologic diagnoses, we semi-quantitatively scored inclusions of tau and TDP-43 both inside LC neuronal somas and in surrounding neuropil. We also digitally measured the percent area occupied of neuromelanin inside of TH-positive LC neurons and in surrounding neuropil to calculate a ratio of extracellular-to-intracellular neuromelanin as an objective composite measure of neurodegeneration. We found that LC tau burden in FTLD-tau was greater than LC TDP-43 burden in FTLD-TDP (z = - 11.38, p < 0.0001). Digital measures of LC neurodegeneration in FTLD-tau were comparable to AD (z = - 1.84, p > 0.05) but greater than FTLD-TDP (z = - 3.85, p < 0.0001) and HC (z = - 4.12, p < 0.0001). Both tau burden and neurodegeneration were consistently elevated in the LC across pathologic and clinical subgroups of FTLD-tau compared to FTLD-TDP subgroups. Moreover, LC tau burden positively correlated with neurodegeneration in the total FTLD group (rho = 0.24, p = 0.001), while TDP-43 burden did not correlate with LC neurodegeneration in FTLD-TDP (rho = - 0.01, p = 0.90). These findings suggest that patterns of disease propagation across all tauopathies include prominent LC tau and neurodegeneration that are relatively distinct from the minimal degenerative changes to the LC in FTLD-TDP and HC. Antemortem detection of LC neurodegeneration and/or function could potentially improve antemortem differentiation of underlying FTLD tauopathies from clinically similar FTLD-TDP proteinopathies.
Collapse
Affiliation(s)
- Daniel T Ohm
- Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Claire Peterson
- Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Rebecca Lobrovich
- Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Katheryn A Q Cousins
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Garrett S Gibbons
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Corey T McMillan
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - David A Wolk
- Alzheimer's Disease Center, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Penn Memory Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Vivianna Van Deerlin
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Alzheimer's Disease Center, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lauren Elman
- Comprehensive Amyotrophic Lateral Sclerosis Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Meredith Spindler
- Parkinson's Disease and Movement Disorders Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Andres Deik
- Parkinson's Disease and Movement Disorders Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Andrew Siderowf
- Parkinson's Disease and Movement Disorders Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - John Q Trojanowski
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Alzheimer's Disease Center, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Edward B Lee
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Alzheimer's Disease Center, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Murray Grossman
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - David J Irwin
- Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| |
Collapse
|
24
|
Labus J, Röhrs KF, Ackmann J, Varbanov H, Müller FE, Jia S, Jahreis K, Vollbrecht AL, Butzlaff M, Schill Y, Guseva D, Böhm K, Kaushik R, Bijata M, Marin P, Chaumont-Dubel S, Zeug A, Dityatev A, Ponimaskin E. Amelioration of Tau pathology and memory deficits by targeting 5-HT7 receptor. Prog Neurobiol 2020; 197:101900. [PMID: 32841723 DOI: 10.1016/j.pneurobio.2020.101900] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 07/21/2020] [Accepted: 08/17/2020] [Indexed: 01/01/2023]
Abstract
Tauopathies comprise a heterogeneous family of neurodegenerative diseases characterized by pathological accumulation of hyperphosphorylated Tau protein. Pathological changes in serotonergic signaling have been associated with tauopathy etiology, but the underlying mechanisms remain poorly understood. Here, we studied the role of the serotonin receptor 7 (5-HT7R), in a mouse model of tauopathy induced by overexpressing the human Tau[R406W] mutant associated with inherited forms of frontotemporal dementia. We showed that the constitutive 5-HT7R activity is required for Tau hyperphosphorylation and formation of highly bundled Tau structures (HBTS) through G-protein-independent, CDK5-dependent mechanism. We also showed that 5-HT7R physically interacts with CDK5. At the systemic level, 5-HT7R-mediated CDK5 activation induces HBTS leading to neuronal death, reduced long-term potentiation (LTP), and impaired memory in mice. Specific blockade of constitutive 5-HT7R activity in neurons that overexpressed Tau[R406W] prevents Tau hyperphosphorylation, aggregation, and neurotoxicity. Moreover, 5-HT7R knockdown in the prefrontal cortex fully abrogates Tau[R406W]-induced LTP deficits and memory impairments. Thus, 5-HT7R/CDK5 signaling emerged as a new, promising target for tauopathy treatments.
Collapse
Affiliation(s)
- Josephine Labus
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Kian-Fritz Röhrs
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany; Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jana Ackmann
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Hristo Varbanov
- Instituite of Neurophysiology, Hannover Medical School, Hannover, Germany; German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Franziska E Müller
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Shaobo Jia
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Kathrin Jahreis
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Anna-Lena Vollbrecht
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Malte Butzlaff
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Yvonne Schill
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Daria Guseva
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Katrin Böhm
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Rahul Kaushik
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Monika Bijata
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany; Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Science, Warsaw, Poland
| | - Philippe Marin
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | | | - Andre Zeug
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Alexander Dityatev
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany; Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany.
| | - Evgeni Ponimaskin
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany; Institute of Neuroscience, Lobachevsky State University of Nizhni Novgorod, Russia.
| |
Collapse
|
25
|
Okaty BW, Sturrock N, Escobedo Lozoya Y, Chang Y, Senft RA, Lyon KA, Alekseyenko OV, Dymecki SM. A single-cell transcriptomic and anatomic atlas of mouse dorsal raphe Pet1 neurons. eLife 2020; 9:e55523. [PMID: 32568072 PMCID: PMC7308082 DOI: 10.7554/elife.55523] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022] Open
Abstract
Among the brainstem raphe nuclei, the dorsal raphe nucleus (DR) contains the greatest number of Pet1-lineage neurons, a predominantly serotonergic group distributed throughout DR subdomains. These neurons collectively regulate diverse physiology and behavior and are often therapeutically targeted to treat affective disorders. Characterizing Pet1 neuron molecular heterogeneity and relating it to anatomy is vital for understanding DR functional organization, with potential to inform therapeutic separability. Here we use high-throughput and DR subdomain-targeted single-cell transcriptomics and intersectional genetic tools to map molecular and anatomical diversity of DR-Pet1 neurons. We describe up to fourteen neuron subtypes, many showing biased cell body distributions across the DR. We further show that P2ry1-Pet1 DR neurons - the most molecularly distinct subtype - possess unique efferent projections and electrophysiological properties. These data complement and extend previous DR characterizations, combining intersectional genetics with multiple transcriptomic modalities to achieve fine-scale molecular and anatomic identification of Pet1 neuron subtypes.
Collapse
Affiliation(s)
- Benjamin W Okaty
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Nikita Sturrock
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | | | - YoonJeung Chang
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Rebecca A Senft
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Krissy A Lyon
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | | | - Susan M Dymecki
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| |
Collapse
|
26
|
The Challenge of Antidepressant Therapeutics in Alzheimer's Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020. [PMID: 32304037 DOI: 10.1007/978-3-030-42667-5_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
The link between depression and Alzheimer's disease (AD) is controversial, because it is not clear if depression is an independent risk factor for the disease or a prodromal symptom in the older population. Cerebral amyloid-β (Aβ) peptide deposition is associated with both cognitive symptoms and neuropsychiatric symptoms (NPS), which may be a biological mechanism of compensation. Despite the widespread use of antidepressant therapeutics (30-50% of patients with AD/dementia are on antidepressants), there is mixed evidence regarding the benefits from their use in AD depression. Monoaminergic antidepressant drugs have shown only modest or no clinical benefits. Therefore, it is important to understand the reason of this drug-resistance and the relationship between antidepressant drugs and the Aβ peptide. The goal of the present review is to highlight the etiology of depression in patients affected by AD in comparison to depressive disorders without AD, and to speculate on more appropriate and alternative therapeutics.
Collapse
|
27
|
Mather M, Huang R, Clewett D, Nielsen SE, Velasco R, Tu K, Han S, Kennedy BL. Isometric exercise facilitates attention to salient events in women via the noradrenergic system. Neuroimage 2020; 210:116560. [PMID: 31978545 PMCID: PMC7061882 DOI: 10.1016/j.neuroimage.2020.116560] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/19/2019] [Accepted: 01/14/2020] [Indexed: 12/21/2022] Open
Abstract
The locus coeruleus (LC) regulates attention via the release of norepinephrine (NE), with levels of tonic LC activity constraining the intensity of phasic LC responses. In the current fMRI study, we used isometric handgrip to modulate tonic LC-NE activity in older women and in young women with different hormone statuses during the time period immediately after the handgrip. During this post-handgrip time, an oddball detection task was used to probe how changes in tonic arousal influenced functional coordination between the LC and a right frontoparietal network that supports attentional selectivity. As expected, the frontoparietal network responded more to infrequent target and novel sounds than to frequent sounds. Across participants, greater LC-frontoparietal functional connectivity, pupil dilation, and faster oddball detection were all positively associated with LC MRI structural contrast from a neuromelanin-sensitive scan. Thus, LC structure was related to LC functional dynamics and attentional performance during the oddball task. We also found that handgrip influenced pupil and attentional processing during a subsequent oddball task. Handgrip decreased subsequent tonic pupil size, increased phasic pupil responses to oddball sounds, speeded oddball detection speed, and increased frontoparietal network activation, suggesting that inducing strong LC activity benefits attentional performance in the next few minutes, potentially due to reduced tonic LC activity. In addition, older women showed a similar benefit of handgrip on frontoparietal network activation as younger women, despite showing lower frontoparietal network activation overall. Together these findings suggest that a simple exercise may improve selective attention in healthy aging, at least for several minutes afterwards.
Collapse
Affiliation(s)
- Mara Mather
- University of Southern California, Leonard Davis School of Gerontology, USA.
| | - Ringo Huang
- University of Southern California, Leonard Davis School of Gerontology, USA
| | - David Clewett
- University of California, Los Angeles, Department of Psychology, USA
| | - Shawn E Nielsen
- University of Southern California, Leonard Davis School of Gerontology, USA
| | - Ricardo Velasco
- University of Southern California, Leonard Davis School of Gerontology, USA
| | - Kristie Tu
- University of Southern California, Leonard Davis School of Gerontology, USA
| | - Sophia Han
- University of Southern California, Leonard Davis School of Gerontology, USA
| | - Briana L Kennedy
- University of Southern California, Leonard Davis School of Gerontology, USA
| |
Collapse
|
28
|
Ehrenberg AJ, Suemoto CK, França Resende EDP, Petersen C, Leite REP, Rodriguez RD, Ferretti-Rebustini REDL, You M, Oh J, Nitrini R, Pasqualucci CA, Jacob-Filho W, Kramer JH, Gatchel JR, Grinberg LT. Neuropathologic Correlates of Psychiatric Symptoms in Alzheimer's Disease. J Alzheimers Dis 2019; 66:115-126. [PMID: 30223398 DOI: 10.3233/jad-180688] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Clarifying the relationships between neuropsychiatric symptoms and Alzheimer's disease (AD)-related pathology may open avenues for effective treatments. Here, we investigate the odds of developing neuropsychiatric symptoms across increasing burdens of neurofibrillary tangle and amyloid-β pathology. Participants who passed away between 2004 and 2014 underwent comprehensive neuropathologic evaluation at the Biobank for Aging Studies from the Faculty of Medicine at the University of São Paulo. Postmortem interviews with reliable informants were used to collect information regarding neuropsychiatric and cognitive status. Of 1,092 cases collected, those with any non-Alzheimer pathology were excluded, bringing the cohort to 455 cases. Braak staging was used to evaluate neurofibrillary tangle burden, and the CERAD neuropathology score was used to evaluate amyloid-β burden. The 12-item neuropsychiatric inventory was used to evaluate neuropsychiatric symptoms and CDR-SOB score was used to evaluate dementia status. In Braak I/II, significantly increased odds were detected for agitation, anxiety, appetite changes, depression, and sleep disturbances, compared to controls. Increased odds of agitation continue into Braak III/IV. Braak V/VI is associated with higher odds for delusions. No increased odds for neuropsychiatric symptoms were found to correlate with amyloid-β pathology. Increased odds of neuropsychiatric symptoms are associated with early neurofibrillary tangle pathology, suggesting that subcortical neurofibrillary tangle accumulation with minimal cortical pathology is sufficient to impact quality of life and that neuropsychiatric symptoms are a manifestation of AD biological processes.
Collapse
Affiliation(s)
- Alexander J Ehrenberg
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.,Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | | | - Elisa de Paula França Resende
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.,Global Brain Health Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Cathrine Petersen
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | | | | | | | - Michelle You
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Jun Oh
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | | | | | | | - Joel H Kramer
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | | | - Lea T Grinberg
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.,University of São Paulo Medical School, São Paulo, Brazil.,Global Brain Health Institute, University of California, San Francisco, San Francisco, CA, USA
| |
Collapse
|
29
|
Nyarko JNK, Quartey MO, Baker GB, Mousseau DD. Can Animal Models Inform on the Relationship between Depression and Alzheimer Disease? CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2019; 64:18-29. [PMID: 29685068 PMCID: PMC6364140 DOI: 10.1177/0706743718772514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The focus on the β-amyloid (Aβ) peptide in clinical Alzheimer disease (AD) as well as in animal models of AD has perhaps biased our understanding of what contributes to the heterogeneity in disease onset and progression. Part of this heterogeneity could reflect the various neuropsychiatric risk factors that present with common symptomatology and can predispose the brain to AD-like changes. One such risk factor is depression. Animal models, particularly mouse models carrying variants of AD-related gene(s), many of which lead to an accumulation of Aβ, suggest that a fundamental shift in depression-related monoaminergic systems (including serotonin and noradrenaline) is a strong indicator of the altered cellular function associated with the earlier(est) stages of AD-related pathology. These changes in monoaminergic neurochemistry could provide for relevant targets for intervention in clinical AD and/or could support a polypharmacy strategy, which might include the targeting of Aβ, in vulnerable populations. Future studies must also include female mice as well as male mice in animal model studies on the relationship between depression and AD.
Collapse
Affiliation(s)
- Jennifer N K Nyarko
- 1 Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Maa O Quartey
- 1 Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Glen B Baker
- 2 Department of Psychiatry, Neuroscience and Mental Health Institute, Neurochemical Research Unit, University of Alberta, Edmonton, Alberta, Canada
| | - Darrell D Mousseau
- 1 Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| |
Collapse
|
30
|
Nyarko JNK, Quartey MO, Heistad RM, Pennington PR, Poon LJ, Knudsen KJ, Allonby O, El Zawily AM, Freywald A, Rauw G, Baker GB, Mousseau DD. Glycosylation States of Pre- and Post-synaptic Markers of 5-HT Neurons Differ With Sex and 5-HTTLPR Genotype in Cortical Autopsy Samples. Front Neurosci 2018; 12:545. [PMID: 30147642 PMCID: PMC6096231 DOI: 10.3389/fnins.2018.00545] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 07/19/2018] [Indexed: 11/13/2022] Open
Abstract
The serotonin (5-hydroxytryptamine, 5-HT) transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) is thought to alter 5-HT signaling and contribute to behavioral and cognitive phenotypes in depression as well as Alzheimer disease (AD). We explored how well the short (S) and long (L) alleles of the 5-HTTLPR align with serotoninergic indices in 60 autopsied cortical samples from early-onset AD/EOAD and late-onset AD/LOAD donors, and age- and sex-matched controls. Stratifying data by either diagnosis-by-genotype or by sex-by-genotype revealed that the donor's 5-HTTLPR genotype, i.e., L/L, S/L, or S/S, did not affect 5-HTT mRNA or protein expression. However, the glycosylation of 5-HTT was significantly higher in control female (vs. male) samples and tended to decrease in female EOAD/LOAD samples, but remained unaltered in male LOAD samples. Glycosylated forms of the vesicular monoamine transporter (VMAT2) were lower in both male and female AD samples, while a sex-by-genotype stratification revealed a loss of VMAT2 glycosylation specifically in females with an L/L genotype. VMAT2 and 5-HTT glycosylation were correlated in male samples and inversely correlated in female samples in both stratification models. The S/S genotype aligned with lower levels of 5-HT turnover in females (but not males) and with an increased glycosylation of the post-synaptic 5-HT2C receptor. Interestingly, the changes in presynaptic glycosylation were evident primarily in female carriers of the APOE ε4 risk factor for AD. Our data do not support an association between 5-HTTLPR genotype and 5-HTT expression, but they do reveal a non-canonical association of 5-HTTLPR genotype with sex-dependent glycosylation changes in pre- and post-synaptic markers of serotoninergic neurons. These patterns of change suggest adaptive responses in 5-HT signaling and could certainly be contributing to the female prevalence in risk for either depression or AD.
Collapse
Affiliation(s)
- Jennifer N K Nyarko
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Maa O Quartey
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ryan M Heistad
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Paul R Pennington
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Lisa J Poon
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Kaeli J Knudsen
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Odette Allonby
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Amr M El Zawily
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Andrew Freywald
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Gail Rauw
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Glen B Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Darrell D Mousseau
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| |
Collapse
|
31
|
Ross JA, Gliebus G, Van Bockstaele EJ. Stress induced neural reorganization: A conceptual framework linking depression and Alzheimer's disease. Prog Neuropsychopharmacol Biol Psychiatry 2018; 85:136-151. [PMID: 28803923 PMCID: PMC5809232 DOI: 10.1016/j.pnpbp.2017.08.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 08/04/2017] [Accepted: 08/06/2017] [Indexed: 12/29/2022]
Abstract
Chronic stress is a risk factor for a number of physiological disorders including cardiovascular disease, obesity and gastrointestinal disorders, as well as psychiatric and neurodegenerative disorders. There are a number of underlying molecular and cellular mechanisms altered in the course of chronic stress, which may increase the vulnerability of individuals to develop psychiatric disorders such as depression, and neurodegenerative disorders such as Alzheimer's Disease (AD). This is evident in the influence of stress on large-scale brain networks, including the resting state Default Mode Network (DMN), the effects of stress on neuronal circuitry and architecture, and the cellular and molecular adaptations to stress, which may render individuals with stress related psychiatric disorders more vulnerable to neurodegenerative disease later in life. These alterations include decreased negative feedback inhibition of the hypothalamic pituitary axis (HPA) axis, decreased dendritic arborization and spine density in the prefrontal cortex (PFC) and hippocampus, and the release of proinflammatory cytokines, which may suppress neurogenesis and promote neuronal cell death. Each of these factors are thought to play a role in stress-related psychiatric disease as well as AD, and have been observed in clinical and post-mortem studies of individuals with depression and AD. The goal of the current review is to summarize clinical and preclinical evidence supporting a role for chronic stress as a putative link between neuropsychiatric and neurodegenerative disease. Moreover, we provide a rationale for the importance of taking a medical history of stress-related psychiatric diseases into consideration during clinical trial design, as they may play an important role in the etiology of AD in stratified patient populations.
Collapse
Affiliation(s)
- Jennifer A. Ross
- Department of Pharmacology and Physiology, College of Medicine, Drexel University, Philadelphia, PA 19102
| | - Gediminas Gliebus
- Department of Neurology, Drexel Neuroscience Institute, Philadelphia, PA 19107
| | | |
Collapse
|
32
|
Brash DE, Goncalves LCP, Bechara EJH. Chemiexcitation and Its Implications for Disease. Trends Mol Med 2018; 24:527-541. [PMID: 29751974 DOI: 10.1016/j.molmed.2018.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/27/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022]
Abstract
Quantum mechanics rarely extends to molecular medicine. Recently, the pigment melanin was found to be susceptible to chemiexcitation, in which an electron is chemically excited to a high-energy molecular orbital. In invertebrates, chemiexcitation causes bioluminescence; in mammals, a higher-energy process involving melanin transfers energy to DNA without photons, creating the lethal and mutagenic cyclobutane pyrimidine dimer that can cause melanoma. This process is initiated by NO and O2- radicals, the formation of which can be triggered by ultraviolet light or inflammation. Several chronic diseases share two properties: inflammation generates these radicals across the tissue, and the diseased cells lie near melanin. We propose that chemiexcitation may be an upstream event in numerous human diseases.
Collapse
Affiliation(s)
- Douglas E Brash
- Departments of Therapeutic Radiology and Dermatology, and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06520-8040, USA.
| | - Leticia C P Goncalves
- Departments of Therapeutic Radiology and Dermatology, and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06520-8040, USA
| | - Etelvino J H Bechara
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo 05513-970 SP, and Departamento de Ciências Exatas e da Terra, Universidade Federal de São Paulo, Diadema, São Paulo 09972-270 SP, Brazil
| | | |
Collapse
|
33
|
Lozupone M, La Montagna M, D'Urso F, Piccininni C, Sardone R, Dibello V, Giannelli G, Solfrizzi V, Greco A, Daniele A, Quaranta N, Seripa D, Bellomo A, Logroscino G, Panza F. Pharmacotherapy for the treatment of depression in patients with alzheimer's disease: a treatment-resistant depressive disorder. Expert Opin Pharmacother 2018; 19:823-842. [PMID: 29726758 DOI: 10.1080/14656566.2018.1471136] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Pharmacotherapy for the treatment of depressive disorders in Alzheimer's Disease (AD) represents a clinical challenge. pharmacological options are often attempted after a period of watchful waiting (8-12 weeks). monoaminergic antidepressant drugs have shown only modest or null clinical benefits, maybe because the etiology of depressive symptoms in ad patients is fundamentally different from that of nondemented subjects. AREAS COVERED The following article looks at the selective serotonin reuptake inhibitor sertraline, which is one of the most frequently studied antidepressant medications in randomized controlled trials (RCTs). It also discusses many other pharmacological approaches that have proven to be inadequate (antipsychotics, acetylcholinesterase inhibitors, anticonvulsants, hormone replacement therapy) and new drug classes (mainly affecting glutamate transmission) that are being studied for treating depression in AD. It also gives discussion to the phase II RCT on the alternative drug S47445 and the potential effect on cognition of the multimodal antidepressant vortioxetine in older depressed patients. Finally, it discusses the N-methyl-D-aspartate antagonist ketamine. EXPERT OPINION The present RCT methodologies are too disparate to draw firm conclusions. Future studies are required to identify effective and multimodal pharmacological treatments that efficiently treat depression in AD. Genotyping may boost antidepressant treatment success.
Collapse
Affiliation(s)
- Madia Lozupone
- a Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs , University of Bari Aldo Moro , Bari , Italy
| | - Maddalena La Montagna
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Francesca D'Urso
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Carla Piccininni
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Rodolfo Sardone
- c Department of Epidemiology and Biostatistics , National Institute of Gastroenterology "S. de Bellis" Research Hospital , Castellana Grotte, Bari , Italy
| | - Vittorio Dibello
- d Interdisciplinary Department of Medicine (DIM), Section of Dentistry , University of Bari Aldo Moro , Bari , Italy
| | - Gianluigi Giannelli
- c Department of Epidemiology and Biostatistics , National Institute of Gastroenterology "S. de Bellis" Research Hospital , Castellana Grotte, Bari , Italy
| | - Vincenzo Solfrizzi
- e Geriatric Medicine-Memory Unit and Rare Disease Centre , University of Bari Aldo Moro , Bari , Italy
| | - Antonio Greco
- f Geriatric Unit & Laboratory of Gerontology and Geriatrics, Department of Medical Sciences , IRCCS "Casa Sollievo della Sofferenza" , San Giovanni Rotondo, Foggia , Italy
| | - Antonio Daniele
- g Institute of Neurology , Catholic University of Sacred Heart , Rome , Italy
| | - Nicola Quaranta
- h Otolaryngology Unit , University of Bari "Aldo Moro" , Bari , Italy
| | - Davide Seripa
- f Geriatric Unit & Laboratory of Gerontology and Geriatrics, Department of Medical Sciences , IRCCS "Casa Sollievo della Sofferenza" , San Giovanni Rotondo, Foggia , Italy
| | - Antonello Bellomo
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Giancarlo Logroscino
- a Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs , University of Bari Aldo Moro , Bari , Italy.,i Department of Clinical Research in Neurology , University of Bari Aldo Moro, "Pia Fondazione Cardinale G. Panico" , Tricase, Lecce , Italy
| | - Francesco Panza
- a Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs , University of Bari Aldo Moro , Bari , Italy.,f Geriatric Unit & Laboratory of Gerontology and Geriatrics, Department of Medical Sciences , IRCCS "Casa Sollievo della Sofferenza" , San Giovanni Rotondo, Foggia , Italy.,i Department of Clinical Research in Neurology , University of Bari Aldo Moro, "Pia Fondazione Cardinale G. Panico" , Tricase, Lecce , Italy
| |
Collapse
|
34
|
Rajmohan R, Reddy PH. Amyloid-Beta and Phosphorylated Tau Accumulations Cause Abnormalities at Synapses of Alzheimer's disease Neurons. J Alzheimers Dis 2018; 57:975-999. [PMID: 27567878 DOI: 10.3233/jad-160612] [Citation(s) in RCA: 267] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amyloid-beta (Aβ) and hyperphosphorylated tau are hallmark lesions of Alzheimer's disease (AD). However, the loss of synapses and dysfunctions of neurotransmission are more directly tied to disease severity. The role of these lesions in the pathoetiological progression of the disease remains contested. Biochemical, cellular, molecular, and pathological studies provided several lines of evidence and improved our understanding of how Aβ and hyperphosphorylated tau accumulation may directly harm synapses and alter neurotransmission. In vitro evidence suggests that Aβ and hyperphosphorylated tau have both direct and indirect cytotoxic effects that affect neurotransmission, axonal transport, signaling cascades, organelle function, and immune response in ways that lead to synaptic loss and dysfunctions in neurotransmitter release. Observations in preclinical models and autopsy studies support these findings, suggesting that while the pathoetiology of positive lesions remains elusive, their removal may reduce disease severity and progression. The purpose of this article is to highlight the need for further investigation of the role of tau in disease progression and its interactions with Aβ and neurotransmitters alike.
Collapse
Affiliation(s)
- Ravi Rajmohan
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - P Hemachandra Reddy
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Speech, Language and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| |
Collapse
|
35
|
Brown EE, Iwata Y, Chung JK, Gerretsen P, Graff-Guerrero A. Tau in Late-Life Depression: A Systematic Review and Meta-Analysis. J Alzheimers Dis 2018; 54:615-33. [PMID: 27497481 DOI: 10.3233/jad-160401] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A lifetime history of major depressive disorder (MDD) increases the risk of developing Alzheimer's disease, of which neurofibrillary tangles due to abnormal tau proteins are a hallmark. We systematically reviewed the literature on tau in MDD and identified 49 relevant articles spanning a number of modalities, including cerebrospinal fluid (CSF) analysis, positron emission tomography, and clinicopathological correlation. We compared CSF total and phosphorylated tau proteins in MDD and controls using a meta-analytic approach. We found no difference in total or phosphorylated tau in MDD. We also found no difference in a comparison of a subgroup excluding studies with significant age differences. Positron emission tomography studies lacked specificity. Clinicopathological studies failed to associate neurofibrillary tangles with MDD. The available data on tau in MDD is limited. The involvement of tau in a subset of MDD cannot be ruled out and requires prospective exploration.
Collapse
Affiliation(s)
- Eric E Brown
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Yusuke Iwata
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Jun Ku Chung
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Philip Gerretsen
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ariel Graff-Guerrero
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| |
Collapse
|
36
|
Molecular imaging of serotonin degeneration in mild cognitive impairment. Neurobiol Dis 2017; 105:33-41. [PMID: 28511918 DOI: 10.1016/j.nbd.2017.05.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/02/2017] [Accepted: 05/12/2017] [Indexed: 01/17/2023] Open
Abstract
Neuropathological and neuroimaging studies have consistently demonstrated degeneration of monoamine systems, especially the serotonin system, in normal aging and Alzheimer's disease. The evidence for degeneration of the serotonin system in mild cognitive impairment is limited. Thus, the goal of the present study was to measure the serotonin transporter in vivo in mild cognitive impairment and healthy controls. The serotonin transporter is a selective marker of serotonin terminals and of the integrity of serotonin projections to cortical, subcortical and limbic regions and is found in high concentrations in the serotonergic cell bodies of origin of these projections (raphe nuclei). Twenty-eight participants with mild cognitive impairment (age 66.6±6.9, 16 males) and 28 healthy, cognitively normal, demographically matched controls (age 66.2±7.1, 15 males) underwent magnetic resonance imaging for measurement of grey matter volumes and high-resolution positron emission tomography with well-established radiotracers for the serotonin transporter and regional cerebral blood flow. Beta-amyloid imaging was performed to evaluate, in combination with the neuropsychological testing, the likelihood of subsequent cognitive decline in the participants with mild cognitive impairment. The following hypotheses were tested: 1) the serotonin transporter would be lower in mild cognitive impairment compared to controls in cortical and limbic regions, 2) in mild cognitive impairment relative to controls, the serotonin transporter would be lower to a greater extent and observed in a more widespread pattern than lower grey matter volumes or lower regional cerebral blood flow and 3) lower cortical and limbic serotonin transporters would be correlated with greater deficits in auditory-verbal and visual-spatial memory in mild cognitive impairment, not in controls. Reduced serotonin transporter availability was observed in mild cognitive impairment compared to controls in cortical and limbic areas typically affected by Alzheimer's disease pathology, as well as in sensory and motor areas, striatum and thalamus that are relatively spared in Alzheimer's disease. The reduction of the serotonin transporter in mild cognitive impairment was greater than grey matter atrophy or reductions in regional cerebral blood flow compared to controls. Lower cortical serotonin transporters were associated with worse performance on tests of auditory-verbal and visual-spatial memory in mild cognitive impairment, not in controls. The serotonin system may represent an important target for prevention and treatment of MCI, particularly the post-synaptic receptors (5-HT4 and 5-HT6), which may not be as severely affected as presynaptic aspects of the serotonin system, as indicated by the observation of lower serotonin transporters in MCI relative to healthy controls.
Collapse
|
37
|
Andrés-Benito P, Fernández-Dueñas V, Carmona M, Escobar LA, Torrejón-Escribano B, Aso E, Ciruela F, Ferrer I. Locus coeruleus at asymptomatic early and middle Braak stages of neurofibrillary tangle pathology. Neuropathol Appl Neurobiol 2017; 43:373-392. [PMID: 28117912 DOI: 10.1111/nan.12386] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/19/2017] [Accepted: 01/24/2017] [Indexed: 12/11/2022]
Abstract
AIMS The present study analyses molecular characteristics of the locus coeruleus (LC) and projections to the amygdala and hippocampus at asymptomatic early and middle Braak stages of neurofibrillary tangle (NFT) pathology. METHODS Immunohistochemistry, whole-transcriptome arrays and RT-qPCR in LC and western blotting in hippocampus and amygdala in a cohort of asymptomatic individuals at stages I-IV of NFT pathology were used. RESULTS NFTs in the LC increased in parallel with colocalized expression of tau kinases, increased neuroketal adducts and decreased superoxide dismutase 1 in neurons with hyperphosphorylated tau and decreased voltage-dependent anion channel in neurons containing truncated tau were found. These were accompanied by increased microglia and AIF1, CD68, PTGS2, IL1β, IL6 and TNF-α gene expression. Whole-transcriptome arrays revealed upregulation of genes coding for proteins associated with heat shock protein binding and genes associated with ATP metabolism and downregulation of genes coding for DNA-binding proteins and members of the small nucleolar RNAs family, at stage IV when compared with stage I. Tyrosine hydroxylase (TH) immunoreactivity was preserved in neurons of the LC, but decreased TH and increased α2A adrenergic receptor protein levels were found in the hippocampus and the amygdala. CONCLUSIONS Complex alteration of several metabolic pathways occurs in the LC accompanying NFT formation at early and middle asymptomatic stages of NFT pathology. Dopaminergic/noradrenergic denervation and increased expression of α2A adrenergic receptor in the hippocampus and amygdala occur at first stage of NFT pathology, suggesting compensatory activation in the face of decreased adrenergic input occurring before clinical evidence of cognitive impairment and depression.
Collapse
Affiliation(s)
- P Andrés-Benito
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - V Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - M Carmona
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - L A Escobar
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - B Torrejón-Escribano
- Unitat de Biologia (BT-E), Serveis Cientifics I Tecnics, Universitat de Barcelona, Madrid, Spain
| | - E Aso
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Hospital Universitari de Bellvitge, Barcelona, Spain.,Departament de Patologia i Terapèutica Experimental, Universitat de Barcelona, L'Hospitalet de Llobregat, Madrid, Spain
| | - F Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - I Ferrer
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Hospital Universitari de Bellvitge, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Departament de Patologia i Terapèutica Experimental, Universitat de Barcelona, L'Hospitalet de Llobregat, Madrid, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
38
|
Ehrenberg AJ, Nguy AK, Theofilas P, Dunlop S, Suemoto CK, Di Lorenzo Alho AT, Leite RP, Diehl Rodriguez R, Mejia MB, Rüb U, Farfel JM, de Lucena Ferretti-Rebustini RE, Nascimento CF, Nitrini R, Pasquallucci CA, Jacob-Filho W, Miller B, Seeley WW, Heinsen H, Grinberg LT. Quantifying the accretion of hyperphosphorylated tau in the locus coeruleus and dorsal raphe nucleus: the pathological building blocks of early Alzheimer's disease. Neuropathol Appl Neurobiol 2017; 43:393-408. [PMID: 28117917 DOI: 10.1111/nan.12387] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/19/2017] [Accepted: 01/24/2017] [Indexed: 01/02/2023]
Abstract
AIMS Hyperphosphorylated tau neuronal cytoplasmic inclusions (ht-NCI) are the best protein correlate of clinical decline in Alzheimer's disease (AD). Qualitative evidence identifies ht-NCI accumulating in the isodendritic core before the entorhinal cortex. Here, we used unbiased stereology to quantify ht-NCI burden in the locus coeruleus (LC) and dorsal raphe nucleus (DRN), aiming to characterize the impact of AD pathology in these nuclei with a focus on early stages. METHODS We utilized unbiased stereology in a sample of 48 well-characterized subjects enriched for controls and early AD stages. ht-NCI counts were estimated in 60-μm-thick sections immunostained for p-tau throughout LC and DRN. Data were integrated with unbiased estimates of LC and DRN neuronal population for a subset of cases. RESULTS In Braak stage 0, 7.9% and 2.6% of neurons in LC and DRN, respectively, harbour ht-NCIs. Although the number of ht-NCI+ neurons significantly increased by about 1.9× between Braak stages 0 to I in LC (P = 0.02), we failed to detect any significant difference between Braak stage I and II. Also, the number of ht-NCI+ neurons remained stable in DRN between all stages 0 and II. Finally, the differential susceptibility to tau inclusions among nuclear subdivisions was more notable in LC than in DRN. CONCLUSIONS LC and DRN neurons exhibited ht-NCI during AD precortical stages. The ht-NCI increases along AD progression on both nuclei, but quantitative changes in LC precede DRN changes.
Collapse
Affiliation(s)
- A J Ehrenberg
- University of California, San Francisco, California, USA.,University of California, Berkeley, California, USA
| | - A K Nguy
- University of California, San Francisco, California, USA.,University of California, Berkeley, California, USA
| | - P Theofilas
- University of California, San Francisco, California, USA
| | - S Dunlop
- University of California, San Francisco, California, USA
| | - C K Suemoto
- University of São Paulo Medical School, São Paulo, Brazil
| | - A T Di Lorenzo Alho
- University of São Paulo Medical School, São Paulo, Brazil.,Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - R P Leite
- University of São Paulo Medical School, São Paulo, Brazil
| | | | - M B Mejia
- University of California, San Francisco, California, USA
| | - U Rüb
- University of Frankfurt, Frankfurt, Germany
| | - J M Farfel
- University of São Paulo Medical School, São Paulo, Brazil
| | | | - C F Nascimento
- University of São Paulo Medical School, São Paulo, Brazil
| | - R Nitrini
- University of São Paulo Medical School, São Paulo, Brazil
| | | | - W Jacob-Filho
- University of São Paulo Medical School, São Paulo, Brazil
| | - B Miller
- University of California, San Francisco, California, USA
| | - W W Seeley
- University of California, San Francisco, California, USA
| | - H Heinsen
- University of São Paulo Medical School, São Paulo, Brazil.,University of Wüerzburg, Wüerzburg, Germany
| | - L T Grinberg
- University of California, San Francisco, California, USA.,University of São Paulo Medical School, São Paulo, Brazil
| |
Collapse
|
39
|
Mehta R, Singh A, Mallick BN. Disciplined sleep for healthy living: Role of noradrenaline. World J Neurol 2017; 7:6-23. [DOI: 10.5316/wjn.v7.i1.6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/10/2016] [Accepted: 11/29/2016] [Indexed: 02/06/2023] Open
Abstract
Sleep is essential for maintaining normal physiological processes. It has been broadly divided into rapid eye movement sleep (REMS) and non-REMS (NREMS); one spends the least amount of time in REMS. Sleep (both NREMS and REMS) disturbance is associated with most altered states, disorders and pathological conditions. It is affected by factors within the body as well as the environment, which ultimately modulate lifestyle. Noradrenaline (NA) is one of the key molecules whose level increases upon sleep-loss, REMS-loss in particular and it induces several REMS-loss associated effects and symptoms. The locus coeruleus (LC)-NAergic neurons are primarily responsible for providing NA throughout the brain. As those neurons project to and receive inputs from across the brain, they are modulated by lifestyle changes, which include changes within the body as well as in the environment. We have reviewed the literature showing how various inputs from outside and within the body integrate at the LC neuronal level to modulate sleep (NREMS and REMS) and vice versa. We propose that these changes modulate NA levels in the brain, which in turn is responsible for acute as well as chronic psycho-somatic disorders and pathological conditions.
Collapse
|
40
|
Santos CY, Snyder PJ, Wu WC, Zhang M, Echeverria A, Alber J. Pathophysiologic relationship between Alzheimer's disease, cerebrovascular disease, and cardiovascular risk: A review and synthesis. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2017; 7:69-87. [PMID: 28275702 PMCID: PMC5328683 DOI: 10.1016/j.dadm.2017.01.005] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
As the population ages due to demographic trends and gains in life expectancy, the incidence and prevalence of dementia increases, and the need to understand the etiology and pathogenesis of dementia becomes ever more urgent. Alzheimer's disease (AD), the most common form of dementia, is a complex disease, the mechanisms of which are poorly understood. The more we learn about AD, the more questions are raised about our current conceptual models of disease. In the absence of a cure or the means by which to slow disease progress, it may be prudent to apply our current knowledge of the intersection between AD, cardiovascular disease, and cerebrovascular disease to foster efforts to delay or slow the onset of AD. This review discusses our current understanding of the epidemiology, genetics, and pathophysiology of AD, the intersection between AD and vascular causes of dementia, and proposes future directions for research and prevention.
Collapse
Affiliation(s)
- Cláudia Y. Santos
- Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - Peter J. Snyder
- Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Wen-Chih Wu
- Division of Cardiology, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Mia Zhang
- Griffith University School of Medicine, Gold Coast, Queensland, Australia
| | - Ana Echeverria
- University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Jessica Alber
- Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI, USA
- Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, USA
| |
Collapse
|
41
|
Farina N, Morrell L, Banerjee S. What is the therapeutic value of antidepressants in dementia? A narrative review. Int J Geriatr Psychiatry 2017; 32:32-49. [PMID: 27593707 DOI: 10.1002/gps.4566] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/17/2016] [Accepted: 07/26/2016] [Indexed: 11/09/2022]
Abstract
OBJECTIVES Antidepressants are commonly used in dementia. Depression is a frequent and important co-morbidity in dementia, and antidepressants are often used to treat depression and more widely. However, there are questions about their utility in depression in dementia and other behavioural and psychological symptoms of dementia. The aim of this narrative review is to summarize the evidence on whether there is therapeutic value in prescribing antidepressants to people with dementia. METHODS A PubMed search was performed to identify randomized controlled trials that prescribed antidepressants to people with dementia, either in the treatment of behavioural and psychological symptoms of dementia (depression, anxiety, agitation/aggression, psychosis and apathy) or for secondary outcomes (quality of life, carer burden, activities of daily living, cognition, clinical severity and adverse events). RESULTS Thirty-six randomized controlled trials were identified (participant n = 3386). A consistent finding in well-designed blinded placebo controlled trials in dementia is the lack of positive effect of antidepressants on outcomes of interest, including depression. One large well-designed study has reported a significant reduction in agitation in people with dementia, but at the expense of clinically significant adverse events. Otherwise, change observed in open trials is also seen in the placebo group, suggesting that any effect is not attributable to the prescription of antidepressants. CONCLUSIONS It is striking how few data there are on indications other than depression. We should question the use of antidepressants in dementia. Definitive trials of clinical effectiveness of specific indications such as anxiety and agitation in dementia and discontinuation of antidepressants in dementia are needed. Copyright © 2016 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Nicolas Farina
- Centre for Dementia Studies, Brighton and Sussex Medical School, Brighton, UK
| | - Lucy Morrell
- Centre for Dementia Studies, Brighton and Sussex Medical School, Brighton, UK
| | - Sube Banerjee
- Centre for Dementia Studies, Brighton and Sussex Medical School, Brighton, UK
| |
Collapse
|
42
|
Luczkowski M. “No screams and cries will convince us that white is white and black is black”, an ode to the defenders of amyloid cascade hypothesis of Alzheimer's disease. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
43
|
Scherder E, Bouma A, Steen L. Effects of peripheral tactile nerve stimulation on affective behavior of patients with probable Alzheimer's disease. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/153331759801300203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the present study, the hypothesis was tested that peripheral tactile nerve stimulation by massage would improve various aspects of affective behavior in patients with probable Alzheimer's disease. It was assumed that peripheral tactile stimulation might activate higher-level brain structures (e.g. the hypothalamus). The present study revealed that patients who were stimulated with tactile stimulation felt less depressed, less anxious, more well tempered, and were more alert. Apart from that, their personal orientation and their environmental orientation in place improved, they were more interested in social contacts and they participated more in activities of daily living. However, the observed effects could not be maintained over a period of six weeks following treatment.
Collapse
Affiliation(s)
| | - Anke Bouma
- Vrije Universiteit, Department of Clinical Psychology, Amsterdam, The Netherlands
| | - Louis Steen
- Centre of Informatics, University of Amsterdam, The Netherlands
| |
Collapse
|
44
|
Flint AJ. Delusions, hallucinations and depression in Alzheimer's disease: A biological perspective. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/153331759100600305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Three symptoms complicating Alzheimer's disease - delusions, hallucinations, and depression - are discussed from a biological perspective. Relevant clinical, radiological and pathological data are reviewed and hypotheses are advanced regarding the possible biological mechanisms of these phenomena. In addition, pharmacological and physical treatments of delusions, hallucinations and depression in Alzheimer's disease are discussed. Areas for future research are suggested.
Collapse
|
45
|
Theofilas P, Dunlop S, Heinsen H, Grinberg LT. Turning on the Light Within: Subcortical Nuclei of the Isodentritic Core and their Role in Alzheimer's Disease Pathogenesis. J Alzheimers Dis 2016; 46:17-34. [PMID: 25720408 DOI: 10.3233/jad-142682] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Pharmacological interventions in Alzheimer's disease (AD) are likely to be more efficacious if administered early in the course of the disease, foregoing the spread of irreversible changes in the brain. Research findings underline an early vulnerability of the isodendritic core (IC) network to AD neurofibrillary lesions. The IC constitutes a phylogenetically conserved subcortical system including the locus coeruleus in pons, dorsal raphe nucleus, and substantia nigra in the midbrain, and nucleus basalis of Meynert in basal forebrain. Through their ascending projections to the cortex, the IC neurons regulate homeostasis and behavior by synthesizing aminergic and cholinergic neurotransmitters. Here we reviewed the evidence demonstrating that neurons of the IC system show neurofibrillary tangles in the earliest stages of AD, prior to cortical pathology, and how this involvement may explain pre-amnestic symptoms, including depression, agitation, and sleep disturbances in AD patients. In fact, clinical and animal studies show a significant reduction of AD cognitive and behavioral symptoms following replenishment of neurotransmitters associated with the IC network. Therefore, the IC network represents a unique candidate for viable therapeutic intervention and should become a high priority for research in AD.
Collapse
Affiliation(s)
- Panos Theofilas
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Sara Dunlop
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Helmut Heinsen
- Department of Pathology, University of Sao Paulo Medical School, Sao Paulo, Brazil.,Department of Psychiatrics, University of Wuerzburg, Germany
| | - Lea Tenenholz Grinberg
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.,Department of Pathology, University of Sao Paulo Medical School, Sao Paulo, Brazil
| |
Collapse
|
46
|
Differential effects of amyloid-beta 1–40 and 1–42 fibrils on 5-HT 1A serotonin receptors in rat brain. Neurobiol Aging 2016; 40:11-21. [DOI: 10.1016/j.neurobiolaging.2015.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 12/08/2015] [Accepted: 12/15/2015] [Indexed: 11/23/2022]
|
47
|
Neurons in Vulnerable Regions of the Alzheimer's Disease Brain Display Reduced ATM Signaling. eNeuro 2016; 3:eN-NWR-0124-15. [PMID: 27022623 PMCID: PMC4770009 DOI: 10.1523/eneuro.0124-15.2016] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/03/2016] [Accepted: 02/06/2016] [Indexed: 01/30/2023] Open
Abstract
Ataxia telangiectasia (A-T) is a multisystemic disease caused by mutations in the ATM (A-T mutated) gene. It strikes before 5 years of age and leads to dysfunctions in many tissues, including the CNS, where it leads to neurodegeneration, primarily in cerebellum. Alzheimer's disease (AD), by contrast, is a largely sporadic neurodegenerative disorder that rarely strikes before the 7th decade of life with primary neuronal losses in hippocampus, frontal cortex, and certain subcortical nuclei. Despite these differences, we present data supporting the hypothesis that a failure of ATM signaling is involved in the neuronal death in individuals with AD. In both, partially ATM-deficient mice and AD mouse models, neurons show evidence for a loss of ATM. In human AD, three independent indices of reduced ATM function-nuclear translocation of histone deacetylase 4, trimethylation of histone H3, and the presence of cell cycle activity-appear coordinately in neurons in regions where degeneration is prevalent. These same neurons also show reduced ATM protein levels. And though they represent only a fraction of the total neurons in each affected region, their numbers significantly correlate with disease stage. This previously unknown role for the ATM kinase in AD pathogenesis suggests that the failure of ATM function may be an important contributor to the death of neurons in AD individuals.
Collapse
|
48
|
Das AK, Pandit R, Maiti S. Effect of amyloids on the vesicular machinery: implications for somatic neurotransmission. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0187. [PMID: 26009766 DOI: 10.1098/rstb.2014.0187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Certain neurodegenerative diseases are thought to be initiated by the aggregation of amyloidogenic proteins. However, the mechanism underlying toxicity remains obscure. Most of the suggested mechanisms are generic in nature and do not directly explain the neuron-type specific lesions observed in many of these diseases. Some recent reports suggest that the toxic aggregates impair the synaptic vesicular machinery. This may lead to an understanding of the neuron-type specificity observed in these diseases. A disruption of the vesicular machinery can also be deleterious for extra-synaptic, especially somatic, neurotransmission (common in serotonergic and dopaminergic systems which are specifically affected in Alzheimer's disease (AD) and Parkinson's disease (PD), respectively), though this relationship has remained unexplored. In this review, we discuss amyloid-induced damage to the neurotransmitter vesicular machinery, with an eye on the possible implications for somatic exocytosis. We argue that the larger size of the system, and the availability of multi-photon microscopy techniques for directly visualizing monoamines, make the somatic exocytosis machinery a more tractable model for understanding the effect of amyloids on all types of vesicular neurotransmission. Indeed, exploring this neglected connection may not just be important, it may be a more fruitful route for understanding AD and PD.
Collapse
Affiliation(s)
- Anand Kant Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, Maharashtra 400005, India
| | - Rucha Pandit
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, Maharashtra 400005, India
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, Maharashtra 400005, India
| |
Collapse
|
49
|
Abstract
As brainstem nuclei are interconnected with several cortical structures and regulate several autonomic, cognitive, and behavioral functions, it might be important to place the brainstem within an important pathologic core in the progression of Alzheimer's disease (AD). Although there have been several postmortem studies reporting neuropathological alterations of the brainstem in AD, there has been no in-vivo structural neuroimaging study of the brainstem in the patients with AD. The aim of this study was to investigate differences in the brainstem volume and shape between patients with AD and elderly normal controls. Fifty AD patients (the Clinical Dementia Rating Scale ≥ 1) and 50 normal controls were recruited, and the brainstem volumes and deformations were compared between the AD and the controls. Patients with AD showed significant total volume [(mean ± SD) 21007 ± 1640 mm] reduction in the brainstem compared with the controls [(mean ± SD) 22530 ± 1750 mm] (P<0.001). In addition, AD patients showed significant brainstem deformations in the upper posterior brainstem corresponding to the midbrain compared with the healthy individuals (false discovery rate corrected P<0.05). This study is the first to explore brainstem volume change and deformations in AD. These structural changes in the midbrain areas might be at the core of the underlying neurobiological mechanisms of brainstem dysfunction with relevance to their various cognitive and behavioral symptoms such as memory impairment, sleep, and emotional disturbance in AD. However, further longitudinal studies might be needed to confirm these findings.
Collapse
|
50
|
|