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Akinyemi DE, Chevre R, Soehnlein O. Neuro-immune crosstalk in hematopoiesis, inflammation, and repair. Trends Immunol 2024; 45:597-608. [PMID: 39030115 DOI: 10.1016/j.it.2024.06.005] [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: 06/16/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/21/2024]
Abstract
Innate immune cells are primary effectors during host defense and in sterile inflammation. Their production in the bone marrow is tightly regulated by growth and niche factors, and their activity at sites of inflammation is orchestrated by a network of alarmins and cytokines. Yet, recent work highlights a significant role of the peripheral nervous system in these processes. Sympathetic neural pathways play a key role in regulating blood cell homeostasis, and sensory neural pathways mediate pro- or anti-inflammatory signaling in a tissue-specific manner. Here, we review emerging evidence of the fine titration of hematopoiesis, leukocyte trafficking, and tissue repair via neuro-immune crosstalk, and how its derailment can accelerate chronic inflammation, as in atherosclerosis.
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Affiliation(s)
- Damilola Emmanuel Akinyemi
- Institute of Experimental Pathology (ExPat), Center of Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany.
| | - Raphael Chevre
- Institute of Experimental Pathology (ExPat), Center of Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Oliver Soehnlein
- Institute of Experimental Pathology (ExPat), Center of Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany.
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Mazzotta GM, Conte C. Alpha Synuclein Toxicity and Non-Motor Parkinson's. Cells 2024; 13:1265. [PMID: 39120295 PMCID: PMC11311369 DOI: 10.3390/cells13151265] [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: 06/13/2024] [Revised: 07/12/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024] Open
Abstract
Parkinson's disease (PD) is a common multisystem neurodegenerative disorder affecting 1% of the population over the age of 60 years. The main neuropathological features of PD are the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the presence of alpha synuclein (αSyn)-rich Lewy bodies both manifesting with classical motor signs. αSyn has emerged as a key protein in PD pathology as it can spread through synaptic networks to reach several anatomical regions of the body contributing to the appearance of non-motor symptoms (NMS) considered prevalent among individuals prior to PD diagnosis and persisting throughout the patient's life. NMS mainly includes loss of taste and smell, constipation, psychiatric disorders, dementia, impaired rapid eye movement (REM) sleep, urogenital dysfunction, and cardiovascular impairment. This review summarizes the more recent findings on the impact of αSyn deposits on several prodromal NMS and emphasizes the importance of early detection of αSyn toxic species in biofluids and peripheral biopsies as prospective biomarkers in PD.
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Affiliation(s)
| | - Carmela Conte
- Department of Pharmaceutical Sciences, University of Perugia, 06126 Perugia, Italy
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Isonaka R, Sullivan P, Holmes C, Goldstein DS. A pathophysiological biomarker combination separates Lewy body from non-Lewy body neurogenic orthostatic hypotension . Clin Auton Res 2024; 34:329-339. [PMID: 38844644 DOI: 10.1007/s10286-024-01035-2] [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: 02/24/2024] [Accepted: 04/24/2024] [Indexed: 07/19/2024]
Abstract
PURPOSE Neurogenic orthostatic hypotension (nOH) results from deficient reflexive delivery of norepinephrine to cardiovascular receptors in response to decreased cardiac venous return. Lewy body (LB) forms of nOH are characterized by low 18F-dopamine-derived radioactivity (a measure of cardiac noradrenergic deficiency), olfactory dysfunction by the University of Pennsylvania Smell Identification Test (UPSIT), and increased deposition of alpha-synuclein (α-syn) in dermal sympathetic noradrenergic nerves by the α-syn-tyrosine hydroxylase (TH) colocalization index. This observational, cross-sectional study explored whether combinations of these biomarkers specifically identify LB forms of nOH. METHODS Clinical laboratory data were reviewed from patients referred for evaluation at the National Institutes of Health for chronic autonomic failure between 2011 and 2023. The cutoff value for low myocardial 18F-dopamine-derived radioactivity was 6000 nCi-kg/cc-mCi, for olfactory dysfunction an UPSIT score ≤ 28, and for an increased α-syn-TH colocalization index ≥ 1.57. RESULTS A total of 44 patients (31 LB, 13 non-LB nOH) had data for all three biomarkers. Compared to the non-LB group, the LB nOH group had low myocardial 18F-dopamine-derived radioactivity, low UPSIT scores, and high α-syn-TH colocalization indexes (p < 0.0001 each). Combining the three biomarkers completely separated the groups. Cluster analysis identified two distinct groups (p < 0.0001) independently of the clinical diagnosis, with one cluster corresponding exactly to LB nOH. CONCLUSION LB forms of nOH feature cardiac noradrenergic deficiency, olfactory dysfunction, and increased α-syn-TH colocalization in skin biopsies. Combining the data for these variables efficiently separates LB from non-LB nOH. Independently of the clinical diagnosis, this biomarker triad identifies a pathophysiologically distinct cluster of nOH patients.
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Affiliation(s)
- Risa Isonaka
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892-1620, USA
| | - Patti Sullivan
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892-1620, USA
| | - Courtney Holmes
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892-1620, USA
| | - David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892-1620, USA.
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Isonaka R, Sullivan P, Holmes C, Goldstein DS. Intra-neuronal alpha-synuclein deposition is related to cardiac noradrenergic deficiency and olfactory dysfunction in neurogenic orthostatic hypotension. RESEARCH SQUARE 2024:rs.3.rs-3988235. [PMID: 38529504 PMCID: PMC10962745 DOI: 10.21203/rs.3.rs-3988235/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Purpose Neurogenic orthostatic hypotension (nOH) results from deficient reflexive delivery of norepinephrine to cardiovascular receptors in response to decreased cardiac venous return. Lewy body (LB) forms of nOH entail low 18F-dopamine-derived radioactivity (a measure of cardiac noradrenergic deficiency), olfactory dysfunction by the University of Pennsylvania Smell Identification Test (UPSIT), and increased deposition of alpha-synuclein (ɑ-syn) in dermal sympathetic noradrenergic nerves by the ɑ-syn-tyrosine hydroxylase (TH) colocalization index. This observational, cross-sectional study explored whether combinations of these biomarkers specifically identify LB forms of nOH. Methods Clinical laboratory data were reviewed from patients referred for evaluation at the National Institutes of Health for chronic autonomic failure between 2011 and 2023. The cutoff value for low myocardial 18F-dopamine-derived radioactivity was 6,000 nCi-kg/cc-mCi, for olfactory dysfunction an UPSIT score ≤ 28, and for an increased ɑ-syn-TH colocalization index ≥ 1.57. Results A total of 44 patients (31 LB, 13 non-LB nOH) had data for all 3 biomarkers. Compared to the non-LB group, the LB nOH group had low myocardial 18F-dopamine-derived radioactivity, low UPSIT scores, and high ɑ-syn-TH colocalization indexes (p<0.0001 each). Combining the 3 biomarkers completely separated the groups. Cluster analysis identified 2 distinct groups (p<0.0001) independently of the clinical diagnosis, 1 cluster corresponding exactly to LB nOH. Conclusion LB forms of nOH feature cardiac noradrenergic deficiency, olfactory dysfunction, and increased ɑ-syn-TH colocalization in skin biopsies. Combining the data for these variables efficiently separates LB from non-LB nOH. Independently of the clinical diagnosis, this biomarker triad identifies a pathophysiologically distinct cluster of nOH patients.
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Affiliation(s)
- Risa Isonaka
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Patti Sullivan
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Courtney Holmes
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - David S. Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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Lenka A, Isonaka R, Holmes C, Goldstein DS. Cardiac 18F-dopamine positron emission tomography predicts the type of phenoconversion of pure autonomic failure. Clin Auton Res 2023; 33:737-747. [PMID: 37843677 DOI: 10.1007/s10286-023-00987-1] [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: 07/10/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023]
Abstract
PURPOSE Pure autonomic failure (PAF) is a rare disease characterized by neurogenic orthostatic hypotension (nOH), no known secondary cause, and lack of a neurodegenerative movement or cognitive disorder. Clinically diagnosed PAF can evolve ("phenoconvert") to a central Lewy body disease [LBD, e.g., Parkinson's disease (PD) or dementia with Lewy bodies (DLB)] or to the non-LBD synucleinopathy multiple system atrophy (MSA). Since cardiac 18F-dopamine-derived radioactivity usually is low in LBDs and usually is normal in MSA, we hypothesized that patients with PAF with low cardiac 18F-dopamine-derived radioactivity would be more likely to phenoconvert to a central LBD than to MSA. METHODS We reviewed data from all the patients seen at the National Institutes of Health Clinical Center from 1994 to 2023 with a clinical diagnosis of PAF and data about 18F-dopamine positron emission tomography (PET). RESULTS Nineteen patients (15 with low 18F-dopamine-derived radioactivity, 4 with normal radioactivity) met the above criteria and had follow-up data. Nine (47%) phenoconverted to a central synucleinopathy over a mean of 6.6 years (range 1.5-18.8 years). All 6 patients with low cardiac 18F-dopamine-derived radioactivity who phenoconverted during follow-up developed a central LBD, whereas none of 4 patients with consistently normal 18F-dopamine PET phenoconverted to a central LBD (p = 0.0048), 3 evolving to probable MSA and 1 upon autopsy having neither a LBD nor MSA. CONCLUSION Cardiac 18F-dopamine PET can predict the type of phenoconversion of PAF. This capability could refine eligibility criteria for entry into disease-modification trials aimed at preventing evolution of PAF to symptomatic central LBDs.
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Affiliation(s)
- Abhishek Lenka
- Autonomic Medicine Section, National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), CNP/DIR/NINDS/NIH, 9000 Rockville Pike MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892, USA
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Risa Isonaka
- Autonomic Medicine Section, National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), CNP/DIR/NINDS/NIH, 9000 Rockville Pike MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892, USA
| | - Courtney Holmes
- Autonomic Medicine Section, National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), CNP/DIR/NINDS/NIH, 9000 Rockville Pike MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892, USA
| | - David S Goldstein
- Autonomic Medicine Section, National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), CNP/DIR/NINDS/NIH, 9000 Rockville Pike MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892, USA.
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Zhou Z, Zhang M, Fang Q, Huang J. Relationship between Parkinson's disease and cardio-cerebrovascular diseases: a Mendelian randomized study. Sci Rep 2023; 13:20428. [PMID: 37993489 PMCID: PMC10665329 DOI: 10.1038/s41598-023-47708-2] [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: 08/13/2023] [Accepted: 11/17/2023] [Indexed: 11/24/2023] Open
Abstract
Parkinson's disease (PD) and cardio-cerebrovascular diseases are related, according to earlier studies, but these studies have some controversy. Our aim was to assess the impact of PD on cardiocerebrovascular diseases using a Mendelian randomization (MR) method. The data for PD were single nucleotide polymorphisms (SNPs) from a publicly available genome-wide association study (GWAS) dataset containing data on 482,730 individuals. And the outcome SNPs data is were derived from five different GWAS datasets. The basic method for MR analysis was the inverse variance weighted (IVW) approach. We use the weighted median method and the MR-Egger method to supplement the MR analysis conclusion. Finally, We used Cochran's Q test to test heterogeneity, MR-PRESSO method and leave-one-out analysis method to perform sensitivity analysis. We used ratio ratios (OR) to assess the strength of the association between exposure and outcome, and 95% confidence intervals (CI) to show the reliability of the results. Our findings imply that PD is linked to a higher occurrence of coronary artery disease (CAD) (OR = 1.055, 95% CI 1.020-1.091, P = 0.001), stroke (OR = 1.039, 95% CI 1.007-1.072, P = 0.014). IVW analyses for stroke's subgroups of ischemic stroke (IS) and 95% CI 1.007-1.072, P = 0.014). IVW analyses for stroke's subgroups of ischemic stroke (IS) and cardioembolic stroke (CES) also yielded positive results, respectively (OR = 1.043, 95% CI 1.008-1.079, P = 0.013), (OR = 1.076, 95% CI 1.008-1.149, P = 0.026). There is no evidence of a relationship between PD and other cardio-cerebrovascular diseases. Additionally, sensitivity analysis revealed reliable outcomes. Our MR study analysis that PD is related with an elevated risk of CAD, stroke, IS, and CES.
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Affiliation(s)
- Zhongzheng Zhou
- The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Muzi Zhang
- The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qinghua Fang
- The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jing Huang
- The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Nabizadeh F, Valizadeh P, Sharifi P, Zafari R, Mirmosayyeb O. Risk of myocardial infarction in Parkinson's disease: A systematic review and meta-analysis. Eur J Neurol 2023; 30:2557-2569. [PMID: 37151196 DOI: 10.1111/ene.15838] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/06/2023] [Accepted: 04/16/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND PURPOSE Previous studies investigating cardiovascular disorders in patients with Parkinson's disease (PD) showed heterogeneous results regarding whether there is a higher or lower risk of myocardial infarction (MI) in these patients compared to the general population. Because of the inconsistency in findings, herein the aim was to perform a systematic review and meta-analysis to investigate the risk of MI in patients with PD. METHODS A comprehensive literature search was performed using four databases, PubMed, Web of Science, Scopus and Embase, in June 2022. Peer-reviewed observational studies comprising case-controls, cohort, cross-sectional and longitudinal studies that reported MI in the PD population were included. RESULTS After the screening, 20 studies with a total of 80,441 patients with PD and 802,857 controls were included in our qualitative and quantitative synthesis. The pooled estimated odds ratio for MI in PD patients compared to controls was 0.80 (95% confidence interval [CI] 0.56-1.05) which indicates that there is no association. The pooled prevalence of MI was 5% (95% CI 3%-7%) with a range of 1%-20% amongst patients with PD. The men (6%, 95% CI 1%-13%) and women (6%, 95% CI 1%-14%, Q = 29.27, I2 = 98.50%, p < 0.001) had similar MI prevalence. CONCLUSION This comprehensive systematic review and meta-analysis provide compelling evidence that PD is associated with a reduced risk of MI. Whilst the exact mechanism underlying this association remains to be fully elucidated, it is clear that certain risk factors for cardiac events appear to be less present in PD patients, which may serve as a protective factor. However, given the reports of increased risk for cerebrovascular events in PD patients, it is possible that the major risk factors for MI and cardiovascular accidents in this population differ. These findings have important implications for clinical management and further research in this area is warranted.
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Affiliation(s)
- Fardin Nabizadeh
- Neuroscience Research Group (NRG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
- School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Parya Valizadeh
- School of Medicine, Tehran University of Medical Science, Tehran, Iran
| | - Parisa Sharifi
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Rasa Zafari
- School of Medicine, Tehran University of Medical Science, Tehran, Iran
| | - Omid Mirmosayyeb
- Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
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Lenka A, Isonaka R, Holmes C, Goldstein DS. Cardiac 18F-Dopamine Positron Emission Tomography Predicts the Type of Phenoconversion of Pure Autonomic Failure. RESEARCH SQUARE 2023:rs.3.rs-3157807. [PMID: 37503103 PMCID: PMC10371148 DOI: 10.21203/rs.3.rs-3157807/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Background Pure autonomic failure (PAF) is a rare disease characterized clinically by neurogenic orthostatic hypotension (nOH) and biochemically by peripheral noradrenergic deficiency. Clinically diagnosed PAF can evolve ("phenoconvert") to a central Lewy body disease (LBD, e.g., Parkinson's disease (PD) or dementia with Lewy bodies (DLB)) or to the non-LBD synucleinopathy multiple system atrophy (MSA). We examined whether cardiac 18F-dopamine positron emission tomography (PET) predicts the trajectory of phenoconversion in PAF. Since cardiac 18F-dopamine-derived radioactivity always is decreased in LBDs with nOH and usually is normal in MSA, we hypothesized that PAF patients with low cardiac 18F-dopamine-derived radioactivity may phenoconvert to a central LBD but do not phenoconvert to MSA. Methods We reviewed data from all the patients seen at the National Institutes of Health Clinical Center from 1994 to 2023 with a clinical diagnosis of PAF and data about serial 18F-dopamine PET. Results Twenty patients met the above criteria. Of 15 with low cardiac 18F-dopamine-derived radioactivity, 6 (40%) phenoconverted to PD or DLB and none to MSA. Of 5 patients with consistently normal 18F-dopamine PET, 4 phenoconverted to MSA, and the other at autopsy had neither a central LBD nor MSA. Conclusion In this case series, 40% of patients with nOH and low cardiac 18F-dopamine-derived radioactivity phenoconverted to PD or DLB during follow-up; none phenoconverted to MSA. Cardiac 18F-DA PET therefore can predict the type of phenoconversion in PAF. This capability could refine eligibility criteria for entry into disease-modification trials aiming to prevent evolution of PAF to symptomatic central LBDs.
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Affiliation(s)
| | - Risa Isonaka
- National Institute of Neurological Disorders and Stroke Intramural Research Program
| | - Courtney Holmes
- National Institute of Neurological Disorders and Stroke Intramural Research Program
| | - David S Goldstein
- National Institute of Neurological Disorders and Stroke Intramural Research Program
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Lamotte G, Singer W. Synucleinopathies. HANDBOOK OF CLINICAL NEUROLOGY 2023; 196:175-202. [PMID: 37620069 DOI: 10.1016/b978-0-323-98817-9.00032-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The α-synucleinopathies include pure autonomic failure, multiple system atrophy, dementia with Lewy bodies, and Parkinson disease. The past two decades have witnessed significant advances in the diagnostic strategies and symptomatic treatment of motor and nonmotor symptoms of the synucleinopathies. This chapter provides an in-depth review of the pathophysiology, pathology, genetic, epidemiology, and clinical and laboratory autonomic features that distinguish the different synucleinopathies with an emphasis on autonomic failure as a common feature. The treatment of the different synucleinopathies is discussed along with the proposal for multidisciplinary, individualized care models that optimally address the various symptoms. There is an urgent need for clinical scientific studies addressing patients at risk of developing synucleinopathies and the investigation of disease mechanisms, biomarkers, potential disease-modifying therapies, and further advancement of symptomatic treatments for motor and nonmotor symptoms.
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Affiliation(s)
- Guillaume Lamotte
- Department of Neurology, University of Utah, Salt Lake City, UT, United States
| | - Wolfgang Singer
- Department of Neurology, Mayo Clinic, Rochester, MN, United States.
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Chua SKK, Saffari SE, Lee SJY, Tan EK. Association Between Parkinson's Disease and Coronary Artery Disease: A Systematic Review and Meta-Analysis. JOURNAL OF PARKINSON'S DISEASE 2022; 12:1737-1748. [PMID: 35694936 PMCID: PMC9789484 DOI: 10.3233/jpd-223291] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The relationship between Parkinson's disease (PD) and coronary artery disease (CAD) is unclear. OBJECTIVE This study aims to investigate whether PD and CAD are associated through systematic review and meta-analysis of observational studies. METHODS Electronic database search of PubMed, EMBASE, and Web of Science for observational studies published from 1 January 2010 to 1 August 2021 was conducted using terms related to PD and CAD. Unadjusted risk ratios (RR) and odds ratios (OR) of included cohort and case-control studies respectively were used to ascertain the association between PD and CAD. Study heterogeneity was evaluated using the I2 test. RESULTS Forty-one full-text studies were initially retrieved for eligibility assessment. Five studies that satisfied the inclusion criteria, consisting of three cohort and two case-control studies, were eventually included in this meta-analysis. The five studies enrolled 35,237 PD patients and 650,866 non-PD patients. PD and CAD were found to be significantly associated in cohort studies (RR = 2.23, 95% CI = 1.08-4.59, p = 0.03; Fig. 2), which held after sensitivity analysis (RR = 1.45, 95% CI = 1.31-1.60, p < 0.001; Fig. 3). Case-control studies found a trend towards association of PD and CAD approaching significance (OR = 1.47, 95% CI = 0.84-2.56, p = 0.18; Fig. 2). CONCLUSION Overall, this meta-analysis suggests that PD is associated with CAD. The underlying mechanisms, as well as the role of ethnicity and other comorbidities on the relationship between PD and CAD should be further explored.
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Affiliation(s)
- Shaun Kai Kiat Chua
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Seyed Ehsan Saffari
- National Neuroscience Institute, Singapore, Singapore,
Health Services & Systems Research, Duke-NUS Medical School, National University of Singapore, Singapore
| | | | - Eng-King Tan
- National Neuroscience Institute, Singapore, Singapore,Correspondence to: Eng-King Tan, MD, Department of Neurology, National Neuroscience Institute, Duke NUS Medical School, Outram Road, Singapore 169608, Singapore. Tel.: +65 63265003; Fax: +65 62203322; E-mail:
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Goldstein DS, Pekker MJ, Sullivan P, Isonaka R, Sharabi Y. Modeling the Progression of Cardiac Catecholamine Deficiency in Lewy Body Diseases. J Am Heart Assoc 2022; 11:e024411. [PMID: 35621196 PMCID: PMC9238705 DOI: 10.1161/jaha.121.024411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 03/15/2022] [Indexed: 11/16/2022]
Abstract
Background Lewy body diseases (LBDs) feature deficiency of the sympathetic neurotransmitter norepinephrine in the left ventricular myocardium and sympathetic intra-neuronal deposition of the protein alpha-synuclein (αS). LBDs therefore are autonomic synucleinopathies. Computational modeling has revealed multiple functional abnormalities in residual myocardial sympathetic noradrenergic nerves in LBDs, including decreased norepinephrine synthesis, vesicular storage, and recycling. We report an extended model that enables predictions about the progression of LBDs and effects of genetic predispositions and treatments on that progression. Methods and Results The model combines cardiac sympathetic activation with autotoxicity mediated by the dopamine metabolite 3,4-dihydroxyphenylacetaldehyde. We tested the model by its ability to predict longitudinal empirical data based on cardiac sympathetic neuroimaging, effects of genetic variations related to particular intra-neuronal reactions, treatment by monoamine oxidase inhibition to decrease 3,4-dihydroxyphenylacetaldehyde production, and post-mortem myocardial tissue contents of catecholamines and αS. The new model generated a triphasic decline in myocardial norepinephrine content. This pattern was confirmed by empirical data from serial cardiac 18F-dopamine positron emission tomographic scanning in patients with LBDs. The model also correctly predicted empirical data about effects of genetic variants and monoamine oxidase inhibition and about myocardial levels of catecholamines and αS. Conclusions The present computational model predicts a triphasic decline in myocardial norepinephrine content as LBDs progress. According to the model, disease-modifying interventions begun at the transition from the first to the second phase delay the onset of symptomatic disease. Computational modeling coupled with biomarkers of preclinical autonomic synucleinopathy may enable early detection and more effective treatment of LBDs.
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Affiliation(s)
- David S. Goldstein
- Autonomic Medicine SectionClinical Neurosciences ProgramDivision of Intramural ResearchNational Institute of Neurological Disorders and StrokeNational Institutes of HealthBethesdaMD
| | - Mark J. Pekker
- Mathematical SciencesUniversity of Alabama at HuntsvilleHuntsvilleAL
| | - Patti Sullivan
- Autonomic Medicine SectionClinical Neurosciences ProgramDivision of Intramural ResearchNational Institute of Neurological Disorders and StrokeNational Institutes of HealthBethesdaMD
| | - Risa Isonaka
- Autonomic Medicine SectionClinical Neurosciences ProgramDivision of Intramural ResearchNational Institute of Neurological Disorders and StrokeNational Institutes of HealthBethesdaMD
| | - Yehonatan Sharabi
- Tel Aviv University Sackler Faculty of Medicine and Chaim Sheba Medical CenterTel HaShomerIsrael
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12
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Lamotte G, Goldstein DS. What new can we learn from cardiac sympathetic neuroimaging in synucleinopathies? Clin Auton Res 2022; 32:95-98. [PMID: 35201527 PMCID: PMC10691841 DOI: 10.1007/s10286-022-00859-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 12/29/2022]
Affiliation(s)
- Guillaume Lamotte
- Sleep and Movement Disorders Division, Department of Neurology, Movement Disorders and Autonomic Disorders Clinic, University of Utah, Salt Lake City, UT, 84108, USA.
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, 20892, USA.
| | - David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, 20892, USA
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Cuenca-Bermejo L, Almela P, Navarro-Zaragoza J, Fernández Villalba E, González-Cuello AM, Laorden ML, Herrero MT. Cardiac Changes in Parkinson's Disease: Lessons from Clinical and Experimental Evidence. Int J Mol Sci 2021; 22:13488. [PMID: 34948285 PMCID: PMC8705692 DOI: 10.3390/ijms222413488] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 01/18/2023] Open
Abstract
Dysautonomia is a common non-motor symptom in Parkinson's disease (PD). Most dysautonomic symptoms appear due to alterations in the peripheral nerves of the autonomic nervous system, including both the sympathetic and parasympathetic nervous systems. The degeneration of sympathetic nerve fibers and neurons leads to cardiovascular dysfunction, which is highly prevalent in PD patients. Cardiac alterations such as orthostatic hypotension, heart rate variability, modifications in cardiogram parameters and baroreflex dysfunction can appear in both the early and late stages of PD, worsening as the disease progresses. In PD patients it is generally found that parasympathetic activity is decreased, while sympathetic activity is increased. This situation gives rise to an imbalance of both tonicities which might, in turn, promote a higher risk of cardiac damage through tachycardia and vasoconstriction. Cardiovascular abnormalities can also appear as a side effect of PD treatment: L-DOPA can decrease blood pressure and aggravate orthostatic hypotension as a result of a negative inotropic effect on the heart. This unwanted side effect limits the therapeutic use of L-DOPA in geriatric patients with PD and can contribute to the number of hospital admissions. Therefore, it is essential to define the cardiac features related to PD for the monitorization of the heart condition in parkinsonian individuals. This information can allow the application of intervention strategies to improve the course of the disease and the proposition of new alternatives for its treatment to eliminate or reverse the motor and non-motor symptoms, especially in geriatric patients.
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Affiliation(s)
- Lorena Cuenca-Bermejo
- Clinical and Experimental Neuroscience Group/Biomedical Research Institute of Murcia (NiCE-IMIB)/Institute for Aging Research, School of Medicine, University of Murcia, 30100 Murcia, Spain; (L.C.-B.); (A.-M.G.-C.)
| | - Pilar Almela
- Department of Pharmacology, School of Medicine, Biomedical Research Institute of Murcia (IMIB), University of Murcia, 30100 Murcia, Spain; (P.A.); (J.N.-Z.); (M.-L.L.)
| | - Javier Navarro-Zaragoza
- Department of Pharmacology, School of Medicine, Biomedical Research Institute of Murcia (IMIB), University of Murcia, 30100 Murcia, Spain; (P.A.); (J.N.-Z.); (M.-L.L.)
| | - Emiliano Fernández Villalba
- Clinical and Experimental Neuroscience Group/Biomedical Research Institute of Murcia (NiCE-IMIB)/Institute for Aging Research, School of Medicine, University of Murcia, 30100 Murcia, Spain; (L.C.-B.); (A.-M.G.-C.)
| | - Ana-María González-Cuello
- Clinical and Experimental Neuroscience Group/Biomedical Research Institute of Murcia (NiCE-IMIB)/Institute for Aging Research, School of Medicine, University of Murcia, 30100 Murcia, Spain; (L.C.-B.); (A.-M.G.-C.)
| | - María-Luisa Laorden
- Department of Pharmacology, School of Medicine, Biomedical Research Institute of Murcia (IMIB), University of Murcia, 30100 Murcia, Spain; (P.A.); (J.N.-Z.); (M.-L.L.)
| | - María-Trinidad Herrero
- Clinical and Experimental Neuroscience Group/Biomedical Research Institute of Murcia (NiCE-IMIB)/Institute for Aging Research, School of Medicine, University of Murcia, 30100 Murcia, Spain; (L.C.-B.); (A.-M.G.-C.)
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Odnoshivkina YG, Petrov AM. The Role of Neuro-Cardiac Junctions
in Sympathetic Regulation of the Heart. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021030078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Goldstein DS. The Catecholaldehyde Hypothesis for the Pathogenesis of Catecholaminergic Neurodegeneration: What We Know and What We Do Not Know. Int J Mol Sci 2021; 22:ijms22115999. [PMID: 34206133 PMCID: PMC8199574 DOI: 10.3390/ijms22115999] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 01/10/2023] Open
Abstract
3,4-Dihydroxyphenylacetaldehyde (DOPAL) is the focus of the catecholaldehyde hypothesis for the pathogenesis of Parkinson’s disease and other Lewy body diseases. The catecholaldehyde is produced via oxidative deamination catalyzed by monoamine oxidase (MAO) acting on cytoplasmic dopamine. DOPAL is autotoxic, in that it can harm the same cells in which it is produced. Normally, DOPAL is detoxified by aldehyde dehydrogenase (ALDH)-mediated conversion to 3,4-dihydroxyphenylacetic acid (DOPAC), which rapidly exits the neurons. Genetic, environmental, or drug-induced manipulations of ALDH that build up DOPAL promote catecholaminergic neurodegeneration. A concept derived from the catecholaldehyde hypothesis imputes deleterious interactions between DOPAL and the protein alpha-synuclein (αS), a major component of Lewy bodies. DOPAL potently oligomerizes αS, and αS oligomers impede vesicular and mitochondrial functions, shifting the fate of cytoplasmic dopamine toward the MAO-catalyzed formation of DOPAL—destabilizing vicious cycles. Direct and indirect effects of DOPAL and of DOPAL-induced misfolded proteins could “freeze” intraneuronal reactions, plasticity of which is required for neuronal homeostasis. The extent to which DOPAL toxicity is mediated by interactions with αS, and vice versa, is poorly understood. Because of numerous secondary effects such as augmented spontaneous oxidation of dopamine by MAO inhibition, there has been insufficient testing of the catecholaldehyde hypothesis in animal models. The clinical pathophysiological significance of genetics, emotional stress, environmental agents, and interactions with numerous proteins relevant to the catecholaldehyde hypothesis are matters for future research. The imposing complexity of intraneuronal catecholamine metabolism seems to require a computational modeling approach to elucidate clinical pathogenetic mechanisms and devise pathophysiology-based, individualized treatments.
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Affiliation(s)
- David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Lamotte G, Benarroch EE. What Is the Clinical Correlation of Cardiac Noradrenergic Denervation in Parkinson Disease? Neurology 2021; 96:748-753. [PMID: 33970873 DOI: 10.1212/wnl.0000000000011805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 02/12/2021] [Indexed: 01/15/2023] Open
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Goldstein DS, Sullivan P, Holmes C, Lamotte G, Lenka A, Sharabi Y. Differential abnormalities of cerebrospinal fluid dopaminergic versus noradrenergic indices in synucleinopathies. J Neurochem 2021; 158:554-568. [PMID: 33894018 DOI: 10.1111/jnc.15371] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/22/2021] [Accepted: 04/15/2021] [Indexed: 12/14/2022]
Abstract
The synucleinopathies Parkinson's disease (PD), multiple system atrophy (MSA), and pure autonomic failure (PAF) are characterized by intra-cytoplasmic deposition of the protein alpha-synuclein and by catecholamine depletion. PAF, which manifests with neurogenic orthostatic hypotension (nOH) and no motor signs of central neurodegeneration, can evolve into PD+nOH. The cerebrospinal fluid (CSF) levels of catecholamine metabolites may indicate central catecholamine deficiency in these synucleinopathies, but the literature is inconsistent and incomplete. In this retrospective cohort study we reviewed data about CSF catecholamines, the dopamine metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the norepinephrine metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG). The compounds were measured in 36 patients with PD, 37 patients with MSA, and 19 patients with PAF and in 38 controls. Compared to the control group, the PD, MSA, and PAF groups had decreased CSF MHPG (p < .0001 each by Dunnett's post hoc test), DHPG (p = .004; p < .0001; p < .0001) and norepinephrine (p = .017; p = .0003; p = .044). CSF HVA and DOPAC were decreased in PD (p < .0001 each) and MSA (p < .0001 each) but not in PAF. The three synucleinopathies therefore have in common in vivo evidence of central noradrenergic deficiency but differ in the extents of central dopaminergic deficiency-prominent in PD and MSA, less apparent in PAF. Data from putamen 18 F-DOPA and cardiac 18 F-dopamine neuroimaging in the same patients, post-mortem tissue catecholamines in largely separate cohorts, and review of the neuropathology literature fit with these distinctions. The results suggest a 'norepinephrine first' ascending pathogenetic sequence in synucleinopathies, with degeneration of pontine locus ceruleus noradrenergic neurons preceding the loss of midbrain substantia nigra dopaminergic neurons.
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Affiliation(s)
- David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Patti Sullivan
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Courtney Holmes
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Guillaume Lamotte
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Abhishek Lenka
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Yehonatan Sharabi
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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Lenka A, Lamotte G, Goldstein DS. Cardiac 18F-Dopamine PET Distinguishes PD with Orthostatic Hypotension from Parkinsonian MSA. Mov Disord Clin Pract 2021; 8:582-586. [PMID: 33981791 PMCID: PMC8088110 DOI: 10.1002/mdc3.13190] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/15/2021] [Accepted: 02/28/2021] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Parkinson's disease with orthostatic hypotension (PD + OH) can be difficult to distinguish clinically from the parkinsonian form of multiple system atrophy (MSA-P). Previous studies examined cardiac sympathetic neuroimaging to differentiate PD from MSA but without focusing specifically on PD + OH versus MSA-P, which often is the relevant differential diagnostic issue. OBJECTIVE To investigate the utility of cardiac sympathetic neuroimaging by 18F-dopamine positron emission tomographic (PET) scanning for separating PD + OH from MSA-P. METHODS Cardiac 18F-dopamine PET data were analyzed from 50 PD + OH and 68 MSA-P patients evaluated at the NIH Clinical Center from 1990 to 2020. Noradrenergic deficiency was defined by interventricular septal 18F-dopamine-derived radioactivity <6000 nCi-kg/cc-mCi in the 5' frame with mid-point 8' after initiation of 3' tracer injection. RESULTS 18F-Dopamine PET separated the PD + OH from the MSA-P group with a sensitivity of 92% and specificity of 96%. CONCLUSION Cardiac 18F-dopamine PET scanning efficiently distinguishes PD + OH from MSA-P.
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Affiliation(s)
- Abhishek Lenka
- Department of NeurologyMedstar Georgetown University HospitalWashington, DCUSA
- Autonomic Medicine Section, National Institute of Neurological Disorders and Stroke (NINDS)National Institutes of Health (NIH)BethesdaMarylandUSA
| | - Guillaume Lamotte
- Autonomic Medicine Section, National Institute of Neurological Disorders and Stroke (NINDS)National Institutes of Health (NIH)BethesdaMarylandUSA
- Department of NeurologyMayo ClinicRochesterMinnesotaUSA
| | - David S. Goldstein
- Autonomic Medicine Section, National Institute of Neurological Disorders and Stroke (NINDS)National Institutes of Health (NIH)BethesdaMarylandUSA
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Goldstein DS. "Sick-but-not-dead": multiple paths to catecholamine deficiency in Lewy body diseases. Stress 2020; 23:633-637. [PMID: 32372682 PMCID: PMC10680065 DOI: 10.1080/10253890.2020.1765158] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/29/2020] [Indexed: 01/05/2023] Open
Abstract
Profound depletion of the catecholamines dopamine (DA) and norepinephrine in the brain, heart, or both characterizes Lewy body diseases such as Parkinson disease, dementia with Lewy bodies, and pure autonomic failure. Although one might presume that catecholamine deficiency in these disorders results directly and solely from loss of catecholaminergic neurons, there is increasing evidence that functional abnormalities in extant residual neurons contribute to the neurotransmitter deficiencies-the "sick-but-not-dead" phenomenon. This brief review highlights two such functional abnormalities-decreased vesicular sequestration of cytoplasmic catecholamines and decreased catecholamine biosynthesis. Another abnormality, decreased activity of aldehyde dehydrogenase, may have pathogenetic significance and contribute indirectly to the loss of catecholamine stores via interactions between the autotoxic catecholaldehyde 3,4-dihydroxyphenylacetaldehyde and the protein alpha-synuclein, which is a major component of Lewy bodies. Theoretically, chronically repeated stress responses could accelerate these abnormalities, via increased exocytosis and neuronal reuptake, which indirectly shifts tissue catecholamines from vesicular stores into the cytoplasm, and via increased tyrosine hydroxylation, which augments intra-cytoplasmic DA production. The discovery of specific paths mediating the sick-but-not-dead phenomenon offers novel targets for multi-pronged therapeutic approaches.
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Affiliation(s)
- David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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Tsukita K, Tachibana N, Hamano T. Appropriate assessment method of 123I-MIBG myocardial scintigraphy for the diagnosis of Lewy body diseases and idiopathic REM sleep behavior disorder. J Neurol 2020; 267:3248-3257. [DOI: 10.1007/s00415-020-09992-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023]
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Goldstein DS. The catecholaldehyde hypothesis: where MAO fits in. J Neural Transm (Vienna) 2020; 127:169-177. [PMID: 31807952 PMCID: PMC10680281 DOI: 10.1007/s00702-019-02106-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 12/13/2022]
Abstract
Monoamine oxidase (MAO) plays a central role in the metabolism of the neurotransmitters dopamine, norepinephrine, and serotonin. This brief review focuses on 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is the immediate product of MAO acting on cytoplasmic dopamine. DOPAL is toxic; however, normally DOPAL is converted via aldehyde dehydrogenase (ALDH) to 3,4-dihydroxyphenylacetic acid (DOPAC), which rapidly exits the neurons. In addition to vesicular uptake of dopamine via the vesicular monoamine transporter (VMAT), the two-enzyme sequence of MAO and ALDH keeps cytoplasmic dopamine levels low. Dopamine oxidizes readily to form toxic products that could threaten neuronal homeostasis. The catecholaldehyde hypothesis posits that diseases featuring catecholaminergic neurodegeneration result from harmful interactions between DOPAL and the protein alpha-synuclein, a major component of Lewy bodies in diseases such as Parkinson disease, dementia with Lewy bodies, and pure autonomic failure. DOPAL potently oligomerizes alpha-synuclein, and alpha-synuclein oligomers impede vesicular functions, shifting the fate of cytoplasmic dopamine toward MAO-catalyzed formation of DOPAL-a vicious cycle. When MAO deaminates dopamine to form DOPAL, hydrogen peroxide is generated; and DOPAL, hydrogen peroxide, and divalent metal cations react to form hydroxyl radicals, which peroxidate lipid membranes. Lipid peroxidation products in turn inhibit ALDH, causing DOPAL to accumulate-another vicious cycle. MAO inhibition decreases DOPAL formation but concurrently increases the spontaneous oxidation of dopamine, potentially trading off one form of toxicity for another. These considerations rationalize a neuroprotection strategy based on concurrent treatment with an MAO inhibitor and an anti-oxidant.
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Affiliation(s)
- David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, 9000 Rockville Pike MSC-1620, Building 10 Room 8N260, Bethesda, MD, 20892-1620, USA.
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