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Ueha R, Miura C, Matsumoto N, Sato T, Goto T, Kondo K. Vocal Fold Motion Impairment in Neurodegenerative Diseases. J Clin Med 2024; 13:2507. [PMID: 38731036 PMCID: PMC11084971 DOI: 10.3390/jcm13092507] [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: 03/30/2024] [Revised: 04/20/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Vocal fold motion impairment (VFMI) is the inappropriate movement of the vocal folds during respiration, leading to vocal fold adduction and/or abduction problems and causing respiratory and vocal impairments. Neurodegenerative diseases (NDDs) are a wide range of disorders characterized by progressive loss of neurons and deposition of altered proteins in the brain and peripheral organs. VFMI may be unrecognized in patients with NDDs. VFMI in NDDs is caused by the following: laryngeal muscle weakness due to muscular atrophy, caused by brainstem and motor neuron degeneration in amyotrophic lateral sclerosis; hyperactivity of laryngeal adductors in Parkinson's disease; and varying degrees of laryngeal adductor hypertonia and abductor paralysis in multiple system atrophy. Management of VFMI depends on whether there is a presence of glottic insufficiency or insufficient glottic opening with/without severe dysphagia. VFMI treatment options for glottic insufficiency range from surgical interventions, including injection laryngoplasty and medialization thyroplasty, to behavioral therapies; for insufficient glottic opening, various options are available based on the severity and underlying cause of the condition, including continuous positive airway pressure therapy, botulinum toxin injection, tracheostomy, vocal fold surgery, or a combination of interventions. In this review, we outline the mechanisms, clinical features, and management of VFMI in NDDs and provide a guide for physicians who may encounter these clinical features in their patients. NDDs are always progressive; hence, timely evaluation, proper diagnosis, and appropriate management of the patient will greatly affect their vocal, respiratory, and swallowing functions as well as their quality of life.
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Affiliation(s)
- Rumi Ueha
- Swallowing Center, The University of Tokyo Hospital, Tokyo 113-8655, Japan
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; (C.M.); (N.M.); (T.S.); (T.G.); (K.K.)
| | - Cathrine Miura
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; (C.M.); (N.M.); (T.S.); (T.G.); (K.K.)
| | - Naoyuki Matsumoto
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; (C.M.); (N.M.); (T.S.); (T.G.); (K.K.)
| | - Taku Sato
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; (C.M.); (N.M.); (T.S.); (T.G.); (K.K.)
| | - Takao Goto
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; (C.M.); (N.M.); (T.S.); (T.G.); (K.K.)
| | - Kenji Kondo
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; (C.M.); (N.M.); (T.S.); (T.G.); (K.K.)
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Orr JE, Chen K, Vaida F, Schmickl CN, Laverty CG, Ravits J, Lesser D, Bhattacharjee R, Malhotra A, Owens RL. Effectiveness of long-term noninvasive ventilation measured by remote monitoring in neuromuscular disease. ERJ Open Res 2023; 9:00163-2023. [PMID: 37753280 PMCID: PMC10518857 DOI: 10.1183/23120541.00163-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/14/2023] [Indexed: 09/28/2023] Open
Abstract
Background and objective Patients with neuromuscular disease are often treated with home noninvasive ventilation (NIV) with devices capable of remote patient monitoring. We sought to determine whether long-term NIV data could provide insight into the effectiveness of ventilation over time. Methods We abstracted available longitudinal data for adults with neuromuscular disease in monthly increments from first available to most recent. Generalised linear mixed-effects modelling with subject-level random effects was used to evaluate trajectories over time. Results 1799 months of data across 85 individuals (median age 61, interquartile range (IQR) 46-71 years; 44% female; 49% amyotrophic lateral sclerosis (ALS)) were analysed, with a median (IQR) of 17 (8-35) months per individual. Over time, tidal volume increased and respiratory rate decreased. Dynamic respiratory system compliance decreased, accompanied by increased pressure support. Compared to volume-assured mode, fixed-pressure modes were associated with lower initial tidal volume, higher respiratory rate and lower pressures, which did not fully equalise with volume-assured mode over time. Compared with non-ALS patients, those with ALS had lower initial pressure support, but faster increases in pressure support over time, and ALS was associated wtih a more robust increase in respiratory rate in response to low tidal volume. Nonsurvivors did not differ from survivors in ventilatory trajectories over time, but did exhibit decreasing NIV use prior to death, in contrast with stable use in survivors. Conclusion NIV keeps breathing patterns stable over time, but support needs are dynamic and influenced by diagnosis and ventilation mode. Mortality is preceded by decreased NIV use rather than inadequate support during use.
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Affiliation(s)
- Jeremy E. Orr
- Division of Pulmonary, Critical Care, and Sleep Medicine, UC San Diego, San Diego, CA, USA
| | - Kenneth Chen
- Division of Pulmonary, Critical Care, and Sleep Medicine, UC San Diego, San Diego, CA, USA
| | - Florin Vaida
- School of Public Health, UC San Diego, San Diego, CA, USA
| | | | | | - John Ravits
- Department of Neurology, UC San Diego, San Diego, CA, USA
| | - Daniel Lesser
- Department of Pediatrics, UC San Diego, San Diego, CA, USA
| | | | - Atul Malhotra
- Division of Pulmonary, Critical Care, and Sleep Medicine, UC San Diego, San Diego, CA, USA
| | - Robert L. Owens
- Division of Pulmonary, Critical Care, and Sleep Medicine, UC San Diego, San Diego, CA, USA
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Nakamagoe K, Matsumoto S, Touno N, Tateno I, Koganezawa T. Saccadic oscillations as a biomarker of clinical symptoms in amyotrophic lateral sclerosis. Neurol Sci 2023; 44:2787-2793. [PMID: 36872386 DOI: 10.1007/s10072-023-06719-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 02/27/2023] [Indexed: 03/07/2023]
Abstract
BACKGROUND Among eye movements in amyotrophic lateral sclerosis (ALS), we identified the characteristics of square-wave jerks (SWJs) seen during times without visual fixation (VF) and analyzed their relationships with clinical parameters. MATERIALS AND METHODS Clinical symptoms were evaluated and eye movements were tested using electronystagmography in 15 patients with ALS (10 men, 5 women; mean age, 66.9 ± 10.5 years). SWJs with and without VF were recorded, and their characteristics were identified. Relationships between each SWJ parameter and clinical symptoms were evaluated. Results were compared with eye movement data from 18 healthy individuals. RESULTS The frequency of SWJs without VF was significantly higher in the ALS group than in the healthy group (P < 0.001). When the condition was changed from VF to no-VF in the ALS group, the frequency of SWJs was significantly higher in healthy subjects (P = 0.004). A positive correlation was seen between frequency of SWJs and percentage predicted forced vital capacity (%FVC) (R = 0.546, P = 0.035). CONCLUSION The frequency of SWJs was higher with VF in healthy people, and was suppressed without VF. In contrast, the frequency of SWJs was not suppressed without VF in ALS patients. This suggests that SWJs without VF have some clinical significance in ALS patients. Moreover, a relationship was noted between the parameters of SWJs without VF in ALS patients and results of pulmonary function tests, suggesting that SWJs during times without VF may offer a clinical parameter of ALS.
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Affiliation(s)
- Kiyotaka Nakamagoe
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
| | - Shunya Matsumoto
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Nozomi Touno
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Ikumi Tateno
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tadachika Koganezawa
- Department of Physiology, Division of Biomedical Science, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
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Tabor Gray L, McElheny KL, Vasilopoulos T, Wymer J, Smith BK, Plowman EK. Predictors of Peak Expiratory Cough Flow in Individuals with Amyotrophic Lateral Sclerosis. Dysphagia 2023; 38:719-725. [PMID: 35931882 DOI: 10.1007/s00455-022-10503-8] [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: 02/03/2022] [Accepted: 07/18/2022] [Indexed: 11/30/2022]
Abstract
Dystussia is prevalent in individuals with amyotrophic lateral sclerosis (ALS), leading to a diminished physiologic capacity to effectively defend the airway. We aimed to identify predictors of peak expiratory cough flow rate in individuals with ALS. One hundred and thirty-four individuals with a confirmed diagnosis of ALS (El-Escorial criteria revised) completed the ALS Functional Rating Scale-Revised (ALSFRS-R) and underwent pulmonary function and cough spirometry testing. Pearson's correlation coefficients and hierarchical multiple regression modeling were conducted to determine predictors of voluntary cough peak expiratory flow rate (p < 0.05). The full model including age, bulbar disease, cough spirometry metrics, and respiratory parameters had a marginal R2 = 0.635, F (7, 126) = 30.241, p < 0.0005, adjusted R2 = 0.61. Maximum expiratory pressure, compression phase, and vital capacity did not contribute and were therefore removed (p < 0.05). The most parsimonious predictive model included age, bulbar disease, peak inspiratory flow rate and duration, peak expiratory rise time, and inspiratory pressure generation with a marginal R2 = 0.543. Although expiratory pressure generation has historically served as the therapeutic target to improve dystussia in ALS, the current dataset highlighted that the inability to quickly and forcefully inspire during the inspiratory phase of voluntary cough places patients at a mechanical disadvantage to generate subsequent high-velocity expiratory airflow to clear the airway. Thus, therapeutic training programs that include both inspiratory and expiratory strength targets may optimize airway clearance capacity in this challenging patient population.
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Affiliation(s)
- Lauren Tabor Gray
- Center for Collaborative Research, NOVA Southeastern University, Fort Lauderdale, FL, USA.
- Aerodigestive Research Core, University of Florida, Gainesville, FL, USA.
| | - Kasey L McElheny
- Aerodigestive Research Core, University of Florida, Gainesville, FL, USA
| | - Terrie Vasilopoulos
- Department of Anesthesiology and Orthopedics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - James Wymer
- Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Barbara K Smith
- Department of Physical Therapy and Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL, USA
| | - Emily K Plowman
- Aerodigestive Research Core, University of Florida, Gainesville, FL, USA
- Department of Neurology, University of Florida, Gainesville, FL, USA
- Speech, Language and Hearing Science Department, University of Florida, Gainesville, FL, USA
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Chen Y, Qin Q, Zhao W, Luo D, Huang Y, Liu G, Kuang Y, Cao Y, Chen Y. Carnosol Reduced Pathogenic Protein Aggregation and Cognitive Impairment in Neurodegenerative Diseases Models via Improving Proteostasis and Ameliorating Mitochondrial Disorders. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:10490-10505. [PMID: 35973126 DOI: 10.1021/acs.jafc.2c02665] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neurodegenerative diseases (NDs) such as Alzheimer's disease, Parkinson's disease, and Huntington's disease are incurable diseases with progressive loss of neural function and require urgent development of effective treatments. Carnosol (CL) reportedly has a pharmacological effect in the prevention of dementia. Nevertheless, the mechanisms of CL's neuroprotection are not entirely clear. The present study aimed to investigate the effects and mechanisms of CL-mediated neuroprotection through Caenorhabditis elegans models. First, CL restored ND protein homeostasis via inhibiting the IIS pathway, regulating MAPK signaling, and simultaneously activating molecular chaperone, thus inhibiting amyloid peptide (Aβ), polyglutamine (polyQ), and α-synuclein (α-syn) deposition and reducing protein disruption-mediated behavioral and cognitive impairments as well as neuronal damages. Furthermore, CL could repair mitochondrial structural damage via improving the mitochondrial membrane protein function and mitochondrial structural homeostasis and improve mitochondrial functional defects via increasing adenosine triphosphate contents, mitochondrial membrane potential, and reactive oxygen species levels, suggesting that CL could improve the ubiquitous mitochondrial defects in NDs. More importantly, we found that CL activated mitochondrial kinetic homeostasis related genes to improve the mitochondrial homeostasis and dysfunction in NDs. Meanwhile, CL up-regulated unc-17, cho-1, and cha-1 genes to alleviate Aβ-mediated cholinergic neurological disorders and activated Notch signaling and the Wnt pathway to diminish polyQ- and α-syn-induced ASH neurons as well as dopaminergic neuron damages. Overall, our study clarified the beneficial anti-ND neuroprotective effects of CL in different aspects and provided new insights into developing CL into products with preventive and therapeutic effects on NDs.
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Affiliation(s)
- Yun Chen
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Qiao Qin
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Wen Zhao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Danxia Luo
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Yingyin Huang
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Guo Liu
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Yong Kuang
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Yong Cao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
| | - Yunjiao Chen
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640 Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640 Guangdong, China
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Kirby AJ, Palmer T, Mead RJ, Ichiyama RM, Chakrabarty S. Caudal-Rostral Progression of Alpha Motoneuron Degeneration in the SOD1 G93A Mouse Model of Amyotrophic Lateral Sclerosis. Antioxidants (Basel) 2022; 11:983. [PMID: 35624847 PMCID: PMC9137889 DOI: 10.3390/antiox11050983] [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: 04/11/2022] [Revised: 05/05/2022] [Accepted: 05/12/2022] [Indexed: 01/27/2023] Open
Abstract
Mice with transgenic expression of human SOD1G93A are a widely used model of ALS, with a caudal-rostral progression of motor impairment. Previous studies have quantified the progression of motoneuron (MN) degeneration based on size, even though alpha (α-) and gamma (γ-) MNs overlap in size. Therefore, using molecular markers and synaptic inputs, we quantified the survival of α-MNs and γ-MNs at the lumbar and cervical spinal segments of 3- and 4-month SOD1G93A mice, to investigate whether there is a caudal-rostral progression of MN death. By 3 months, in the cervical and lumbar spinal cord, there was α-MN degeneration with complete γ-MN sparing. At 3 months, the cervical spinal cord had more α-MNs per ventral horn than the lumbar spinal cord in SOD1G93A mice. A similar spatial trend of degeneration was observed in the corticospinal tract, which remained intact in the cervical spinal cord at 3- and 4- months of age. These findings agree with the corticofugal synaptopathy model that α-MNs and CST of the lumbar spinal cord are more susceptible to degeneration in SOD1G93A mice. Hence, there is a spatial and temporal caudal-rostral progression of α-MN and CST degeneration in SOD1G93A mice.
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Affiliation(s)
- Alastair J. Kirby
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK; (A.J.K.); (T.P.); (R.M.I.)
| | - Thomas Palmer
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK; (A.J.K.); (T.P.); (R.M.I.)
| | - Richard J. Mead
- Sheffield Institute of Translational Neuroscience, University of Sheffield, 385a Glossop Road, Sheffield S10 2HQ, UK;
| | - Ronaldo M. Ichiyama
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK; (A.J.K.); (T.P.); (R.M.I.)
| | - Samit Chakrabarty
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK; (A.J.K.); (T.P.); (R.M.I.)
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Vose AK, Welch JF, Nair J, Dale EA, Fox EJ, Muir GD, Trumbower RD, Mitchell GS. Therapeutic acute intermittent hypoxia: A translational roadmap for spinal cord injury and neuromuscular disease. Exp Neurol 2022; 347:113891. [PMID: 34637802 PMCID: PMC8820239 DOI: 10.1016/j.expneurol.2021.113891] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/29/2021] [Accepted: 10/03/2021] [Indexed: 01/03/2023]
Abstract
We review progress towards greater mechanistic understanding and clinical translation of a strategy to improve respiratory and non-respiratory motor function in people with neuromuscular disorders, therapeutic acute intermittent hypoxia (tAIH). In 2016 and 2020, workshops to create and update a "road map to clinical translation" were held to help guide future research and development of tAIH to restore movement in people living with chronic, incomplete spinal cord injuries. After briefly discussing the pioneering, non-targeted basic research inspiring this novel therapeutic approach, we then summarize workshop recommendations, emphasizing critical knowledge gaps, priorities for future research effort, and steps needed to accelerate progress as we evaluate the potential of tAIH for routine clinical use. Highlighted areas include: 1) greater mechanistic understanding, particularly in non-respiratory motor systems; 2) optimization of tAIH protocols to maximize benefits; 3) identification of combinatorial treatments that amplify plasticity or remove plasticity constraints, including task-specific training; 4) identification of biomarkers for individuals most/least likely to benefit from tAIH; 5) assessment of long-term tAIH safety; and 6) development of a simple, safe and effective device to administer tAIH in clinical and home settings. Finally, we update ongoing clinical trials and recent investigations of tAIH in SCI and other clinical disorders that compromise motor function, including ALS, multiple sclerosis, and stroke.
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Affiliation(s)
- Alicia K Vose
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brooks Rehabilitation, Jacksonville, FL 32216, USA
| | - Joseph F Welch
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brooks Rehabilitation, Jacksonville, FL 32216, USA
| | - Jayakrishnan Nair
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Erica A Dale
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32610, USA
| | - Emily J Fox
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brooks Rehabilitation, Jacksonville, FL 32216, USA
| | - Gillian D Muir
- Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Randy D Trumbower
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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Mitchell GS, Baker TL. Respiratory neuroplasticity: Mechanisms and translational implications of phrenic motor plasticity. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:409-432. [PMID: 35965036 DOI: 10.1016/b978-0-323-91534-2.00016-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Widespread appreciation that neuroplasticity is an essential feature of the neural system controlling breathing has emerged only in recent years. In this chapter, we focus on respiratory motor plasticity, with emphasis on the phrenic motor system. First, we define related but distinct concepts: neuromodulation and neuroplasticity. We then focus on mechanisms underlying two well-studied models of phrenic motor plasticity: (1) phrenic long-term facilitation following brief exposure to acute intermittent hypoxia; and (2) phrenic motor facilitation after prolonged or recurrent bouts of diminished respiratory neural activity. Advances in our understanding of these novel and important forms of plasticity have been rapid and have already inspired translation in multiple respects: (1) development of novel therapeutic strategies to preserve/restore breathing function in humans with severe neurological disorders, such as spinal cord injury and amyotrophic lateral sclerosis; and (2) the discovery that similar plasticity also occurs in nonrespiratory motor systems. Indeed, the realization that similar plasticity occurs in respiratory and nonrespiratory motor neurons inspired clinical trials to restore leg/walking and hand/arm function in people living with chronic, incomplete spinal cord injury. Similar application may be possible to other clinical disorders that compromise respiratory and non-respiratory movements.
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Affiliation(s)
- Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United States.
| | - Tracy L Baker
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States
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Borkowski LF, Keilholz AN, Smith CL, Canda KA, Nichols NL. Nonsteroidal anti-inflammatory drug (ketoprofen) delivery differentially impacts phrenic long-term facilitation in rats with motor neuron death induced by intrapleural CTB-SAP injections. Exp Neurol 2022; 347:113892. [PMID: 34634309 PMCID: PMC10805451 DOI: 10.1016/j.expneurol.2021.113892] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 09/05/2021] [Accepted: 10/05/2021] [Indexed: 11/22/2022]
Abstract
Intrapleural injections of cholera toxin B conjugated to saporin (CTB-SAP) selectively eliminates respiratory (e.g., phrenic) motor neurons, and mimics motor neuron death and respiratory deficits observed in rat models of neuromuscular diseases. Additionally, microglial density increases in the phrenic motor nucleus following CTB-SAP. This CTB-SAP rodent model allows us to study the impact of motor neuron death on the output of surviving phrenic motor neurons, and the underlying mechanisms that contribute to enhancing or constraining their output at 7 days (d) or 28d post-CTB-SAP injection. 7d CTB-SAP rats elicit enhanced phrenic long-term facilitation (pLTF) through the Gs-pathway (inflammation-resistant in naïve rats), while pLTF is elicited though the Gq-pathway (inflammation-sensitive in naïve rats) in control and 28d CTB-SAP rats. In 7d and 28d male CTB-SAP rats and controls, we evaluated the effect of cyclooxygenase-1/2 enzymes on pLTF by delivery of the nonsteroidal anti-inflammatory drug, ketoprofen (IP), and we hypothesized that pLTF would be unaffected by ketoprofen in 7d CTB-SAP rats, but pLTF would be enhanced in 28d CTB-SAP rats. In anesthetized, paralyzed and ventilated rats, pLTF was surprisingly attenuated in 7d CTB-SAP rats and enhanced in 28d CTB-SAP rats (both p < 0.05) following ketoprofen delivery. Additionally in CTB-SAP rats: 1) microglia were more amoeboid in the phrenic motor nucleus; and 2) cervical spinal inflammatory-associated factor expression (TNF-α, BDNF, and IL-10) was increased vs. controls in the absence of ketoprofen (p < 0.05). Following ketoprofen delivery, TNF-α and IL-10 expression was decreased back to control levels, while BDNF expression was differentially affected over the course of motor neuron death in CTB-SAP rats. This study furthers our understanding of factors (e.g., cyclooxygenase-1/2-induced inflammation) that contribute to enhancing or constraining pLTF and its implications for breathing following respiratory motor neuron death.
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Affiliation(s)
- Lauren F Borkowski
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Amy N Keilholz
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Catherine L Smith
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Kaylie A Canda
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA.
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10
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Young C, Ealing J, McDermott C, Williams T, Al-Chalabi A, Majeed T, Roberts R, Mills R, Tennant A. Fatigue and anxiety mediate the effect of dyspnea on quality of life in amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2021; 23:390-398. [PMID: 34709092 DOI: 10.1080/21678421.2021.1990343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Introduction: Dyspnea (or breathlessness) due to progressive neuromuscular respiratory failure is common in amyotrophic lateral sclerosis (ALS). It is associated with anxiety, depression and reduced quality of life (QoL). For effective treatment, it is essential to understand the relationships between dyspnea, anxiety, depression and QoL.Methods: The UK Trajectories of Outcomes in Neurological Conditions-ALS study (TONiC-ALS) collected self-report measures from patients with ALS. Ordinal scales were transformed to interval-scaled estimates by the Rasch Measurement model. They were subsequently included in a series of path models where the focal relationships were dyspnea to QoL and dyspnea to depression.Results: Path analyses using 1022 participants showed that 60.5% of the variance of QoL was explained by fatigue, anxiety, dyspnea and disability. For depression, 54.1% of the variance was explained by a model of these factors. Dyspnea played an important but mostly indirect role in influencing QoL and depressive symptoms. Disability was dominated by all other factors in the model.Discussion: Dyspnea in ALS influences quality of life and depression largely through indirect effects, principally acting via anxiety and fatigue. Recognition of this is essential for clinicians to understand where to intervene for greatest benefit. Researchers must be aware that studies of the effect of dyspnea on QoL and depression require path models, measuring both direct and indirect effects, as the impact of dyspnea is likely to be significantly miscalculated if only direct effects are assessed.
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Affiliation(s)
- Carolyn Young
- Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, UK.,University of Liverpool, Liverpool, UK
| | - John Ealing
- Salford Royal Foundation Trust, Manchester, UK
| | | | - Tim Williams
- Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Ammar Al-Chalabi
- Department of Basic and Clinical Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.,Department of Neurology, King's College Hospital, London, UK
| | | | | | - Roger Mills
- Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, UK.,University of Liverpool, Liverpool, UK
| | - Alan Tennant
- Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK
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11
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Garbuzova-Davis S, Shell R, Mustafa H, Hailu S, Willing AE, Sanberg PR, Borlongan CV. Advancing Stem Cell Therapy for Repair of Damaged Lung Microvasculature in Amyotrophic Lateral Sclerosis. Cell Transplant 2021; 29:963689720913494. [PMID: 32207340 PMCID: PMC7444221 DOI: 10.1177/0963689720913494] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease of motor neuron
degeneration in the brain and spinal cord. Progressive paralysis of
the diaphragm and other respiratory muscles leading to respiratory
dysfunction and failure is the most common cause of death in ALS
patients. Respiratory impairment has also been shown in animal models
of ALS. Vascular pathology is another recently recognized hallmark of
ALS pathogenesis. Central nervous system (CNS) capillary damage is a
shared disease element in ALS rodent models and ALS patients.
Microvascular impairment outside of the CNS, such as in the lungs, may
occur in ALS, triggering lung damage and affecting breathing function.
Stem cell therapy is a promising treatment for ALS. However, this
therapeutic strategy has primarily targeted rescue of degenerated
motor neurons. We showed functional benefits from intravenous delivery
of human bone marrow (hBM) stem cells on restoration of capillary
integrity in the CNS of an superoxide dismutase 1 (SOD1) mouse model
of ALS. Due to the widespread distribution of transplanted cells via
this route, administered cells may enter the lungs and effectively
restore microvasculature in this respiratory organ. Here, we provided
preliminary evidence of the potential role of microvasculature
dysfunction in prompting lung damage and treatment approaches for
repair of respiratory function in ALS. Our initial studies showed
proof-of-principle that microvascular damage in ALS mice results in
lung petechiae at the late stage of disease and that systemic
transplantation of mainly hBM-derived endothelial progenitor cells
shows potential to promote lung restoration via re-established
vascular integrity. Our new understanding of previously underexplored
lung competence in this disease may facilitate therapy targeting
restoration of respiratory function in ALS.
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Affiliation(s)
- Svitlana Garbuzova-Davis
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Robert Shell
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Hilmi Mustafa
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Surafuale Hailu
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Alison E Willing
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Paul R Sanberg
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Cesario V Borlongan
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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12
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Borkowski LF, Nichols NL. Differential mechanisms are required for phrenic long-term facilitation over the course of motor neuron loss following CTB-SAP intrapleural injections. Exp Neurol 2020; 334:113460. [PMID: 32916172 PMCID: PMC10823911 DOI: 10.1016/j.expneurol.2020.113460] [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] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 01/25/2023]
Abstract
Selective elimination of respiratory motor neurons using intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) mimics motor neuron death and respiratory deficits observed in rat models of neuromuscular diseases. This CTB-SAP model allows us to study the impact of motor neuron death on the output of surviving phrenic motor neurons. After 7(d) days of CTB-SAP, phrenic long-term facilitation (pLTF, a form of respiratory plasticity) is enhanced, but returns towards control levels at 28d. However, the mechanism responsible for this difference in magnitude of pLTF is unknown. In naïve rats, pLTF predominately requires 5-HT2 receptors, the new synthesis of BDNF, and MEK/ERK signaling; however, pLTF can alternatively be induced via A2A receptors, the new synthesis of TrkB, and PI3K/Akt signaling. Since A2A receptor-dependent pLTF is enhanced in naïve rats, we suggest that 7d CTB-SAP treated rats utilize the alternative mechanism for pLTF. Here, we tested the hypothesis that pLTF following CTB-SAP is: 1) TrkB and PI3K/Akt, not BDNF and MEK/ERK, dependent at 7d; and 2) BDNF and MEK/ERK, not TrkB and PI3K/Akt, dependent at 28d. Adult Sprague Dawley male rats were anesthetized, paralyzed, ventilated, and were exposed to acute intermittent hypoxia (AIH; 3, 5 min bouts of 10.5% O2) following bilateral, intrapleural injections at 7d and 28d of: 1) CTB-SAP (25 μg), or 2) un-conjugated CTB and SAP (control). Intrathecal C4 delivery included either: 1) small interfering RNA that targeted BDNF or TrkB mRNA; 2) UO126 (MEK/ERK inhibitor); or 3) PI828 (PI3K/Akt inhibitor). Our data suggest that pLTF in 7d CTB-SAP treated rats is elicited primarily through TrkB and PI3K/Akt-dependent mechanisms, whereas BDNF and MEK/ERK-dependent mechanisms induce pLTF in 28d CTB-SAP treated rats. This project increases our understanding of respiratory plasticity and its implications for breathing following motor neuron death.
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Affiliation(s)
- Lauren F Borkowski
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America
| | - Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America.
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13
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Pinto S, Swash M, De Carvalho M. Mouth occlusion pressure at 100ms (P0.1) as a respiratory biomarker in amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2020; 22:53-60. [PMID: 32955378 DOI: 10.1080/21678421.2020.1821061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Airway pressure in the first 100ms of an occluded inspiration (P0.1) evaluates the respiratory center activity, increasing in the presence of respiratory muscle weakness. It is uncertain if its activity can compensate for respiratory muscles weakness in amyotrophic lateral sclerosis (ALS). Methods: Consecutive ALS patients with P0.1 evaluated at first visit were included. Depending on P0.1 percentile, patients were divided in three groups: G1 (<25th percentile); G2 (25th-74th percentiles); G3 (≥75th percentile); two subgroups were further considered: SG0 (<10th percentile); SG1 (>90th percentile). Body mass index (BMI), functional ALS rating scale and its subscores, respiratory function tests, including forced vital capacity, maximal inspiratory (MIP) and expiratory pressures, percentage of P0.1 (%P0.1), blood gas analyses, phrenic nerve motor amplitude (MeanPhrenAmpl) were compared. P0.1/MIP and %P0.1 predictors were explored by linear and multinomial logistic regression analyses. p < 0.05 was considered as significant. Results: From the 497 patients included, 124 were in G1 and G3 each, 249 in G2, 49 in SG0 and SG1 each. G1 included more men, with higher BMI (p < 0.001). G3 had older women, with predominant bulbar phenotype (p < 0.001). Lower respiratory function (p < 0.05) was present in both groups. SG0 (%P0.1 < 51.73%, P0.1/MIP = 1.48 ± 1.02) had more spinal-onset men (p < 0.001) with lower MeanPhrenAmpl (p < 0.004). SG1 (P0.1 > 147.12, P0.1/MIP = 7.92 ± 4.62) predominantly included older patients (p = 0.033), women (p = 0.012), with lower MeanPhrenAmpl (p = 0.039). Discussion: ALS patients with respiratory failure can show high or low P01 values, related to phenotype. Possible central drive reactivity and exhaustion, and the role of respiratory-metabolic-renal buffering system should be further addressed.
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Affiliation(s)
- Susana Pinto
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Michael Swash
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Mamede De Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Department of Neurosciences and Mental Health, Hospital de Santa Maria, Centro Hospitalar Universitário de Lisboa Norte, Lisbon, Portugal
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14
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Tabor-Gray L, Vasilopoulos T, Plowman EK. Differences in voluntary and reflexive cough strength in individuals with amyotrophic lateral sclerosis and healthy adults. Muscle Nerve 2020; 62:597-600. [PMID: 32776561 DOI: 10.1002/mus.27040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Dystussia impacts the ability to protect the airway. Voluntary cough provides a metric of airway defense but differs from the reflexive response to aspiration during swallowing. Therefore, we evaluated relationships between voluntary and reflexive cough among individuals with amyotrophic lateral sclerosis (ALS) and a healthy cohort. METHODS Twenty-eight individuals with ALS and 26 healthy individuals completed voluntary and reflexive cough testing. Descriptive statistics, reliability, and paired t tests were conducted to evaluate differences in cough volume acceleration (CVA) and peak expiratory flow rate (PEFR) in voluntary vs reflexive cough. RESULTS Compared with reflexive cough, voluntary CVA and PEFR were greater in individuals with ALS [t(27) = 4.83, P < .001 and t(27) = 8.69, P < .001] and the healthy cohort [t(21) = 5.91, P < .001 and t(21) = 12.26, P < .001], respectively. DISCUSSION These findings hold important implications for the use and interpretation of voluntary peak cough flow during clinical swallowing evaluations.
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Affiliation(s)
- Lauren Tabor-Gray
- Department of Neurology, Phil Smith Neuroscience Institute, Fort Lauderdale, Florida, USA.,Swallowing Systems Core, University of Florida, Gainesville, Florida, USA
| | - Terrie Vasilopoulos
- Department of Anesthesiology and Orthopedics, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Emily K Plowman
- Swallowing Systems Core, University of Florida, Gainesville, Florida, USA.,Speech, Language and Hearing Science Department, University of Florida, Gainesville, Florida, USA.,Department of Neurology, University of Florida, Gainesville, Florida, USA
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15
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McCall AL, Dhindsa JS, Pucci LA, Kahn AF, Fusco AF, Biswas DD, Strickland LM, Tseng HC, ElMallah MK. Respiratory pathology in the Optn -/- mouse model of Amyotrophic Lateral Sclerosis. Respir Physiol Neurobiol 2020; 282:103525. [PMID: 32805420 DOI: 10.1016/j.resp.2020.103525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/29/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disorder that results in death due to respiratory failure. Many genetic defects are associated with ALS; one such defect is a mutation in the gene encoding optineurin (OPTN). Using an optineurin null mouse (Optn-/-), we sought to characterize the impact of optineurin deficiency on respiratory neurodegeneration. Respiratory function was assessed at 6 and 12 mo of age using whole body plethysmography at baseline during normoxia (FiO2: 0.21; N2 balance) and during a respiratory challenge with hypoxia and hypercapnia (FiCO2: 0.07, FiO2: 0.10; N2 balance). Histological analyses to assess motor neuron viability and respiratory nerve integrity were performed in the medulla, cervical spinal cord, hypoglossal nerve, and phrenic nerve. Minute ventilation, peak inspiratory flow, and peak expiratory flow are significantly reduced during a respiratory challenge in 6 mo Optn-/-mice. By 12 mo, tidal volume is also significantly reduced in Optn-/- mice. Furthermore, 12mo Optn-/- mice exhibit hypoglossal motor neuron loss, phrenic and hypoglossal dysmyelination, and accumulated mitochondria in the hypoglossal nerve axons. Overall, these data indicate that Optn-/- mice display neurodegenerative respiratory dysfunction and are a useful model to study the impact of novel therapies on respiratory function for optineurin-deficient ALS patients.
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Affiliation(s)
- Angela L McCall
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Justin S Dhindsa
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Logan A Pucci
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Amanda F Kahn
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Anna F Fusco
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Debolina D Biswas
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Laura M Strickland
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Henry C Tseng
- Duke Eye Center and Department of Ophthalmology, School of Medicine, Duke University, Durham, North Carolina 27710, USA
| | - Mai K ElMallah
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA.
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16
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Lind LA, Andel EM, McCall AL, Dhindsa JS, Johnson KA, Stricklin OE, Mueller C, ElMallah MK, Lever TE, Nichols NL. Intralingual Administration of AAVrh10-miR SOD1 Improves Respiratory But Not Swallowing Function in a Superoxide Dismutase-1 Mouse Model of Amyotrophic Lateral Sclerosis. Hum Gene Ther 2020; 31:828-838. [PMID: 32498636 DOI: 10.1089/hum.2020.065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by degeneration of motor neurons and muscles, and death is usually a result of impaired respiratory function due to loss of motor neurons that control upper airway muscles and/or the diaphragm. Currently, no cure for ALS exists and treatments to date do not significantly improve respiratory or swallowing function. One cause of ALS is a mutation in the superoxide dismutase-1 (SOD1) gene; thus, reducing expression of the mutated gene may slow the progression of the disease. Our group has been studying the SOD1G93A transgenic mouse model of ALS that develops progressive respiratory deficits and dysphagia. We hypothesize that solely treating the tongue in SOD1 mice will preserve respiratory and swallowing function, and it will prolong survival. At 6 weeks of age, 11 SOD1G93A mice (both sexes) received a single intralingual injection of gene therapy (AAVrh10-miRSOD1). Another 29 mice (both sexes) were divided into two control groups: (1) 12 SOD1G93A mice that received a single intralingual vehicle injection (saline); and (2) 17 non-transgenic littermates. Starting at 13 weeks of age, plethysmography (respiratory parameters) at baseline and in response to hypoxia (11% O2) + hypercapnia (7% CO2) were recorded and videofluoroscopic swallow study testing were performed twice monthly until end-stage disease. Minute ventilation during hypoxia + hypercapnia and mean inspiratory flow at baseline were significantly reduced (p < 0.05) in vehicle-injected, but not AAVrh10-miRSOD1-injected SOD1G93A mice as compared with wild-type mice. In contrast, swallowing function was unchanged by AAVrh10-miRSOD1 treatment (p > 0.05). AAVrh10-miRSOD1 injections also significantly extended survival in females by ∼1 week. In conclusion, this study indicates that intralingual AAVrh10-miRSOD1 treatment preserved respiratory (but not swallowing) function potentially via increasing upper airway patency, and it is worthy of further exploration as a possible therapy to preserve respiratory capacity in ALS patients.
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Affiliation(s)
- Lori A Lind
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Ellyn M Andel
- Department of Otolaryngology, University of Missouri, Columbia, Missouri, USA
| | - Angela L McCall
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Justin S Dhindsa
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Katherine A Johnson
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Olivia E Stricklin
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Christian Mueller
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Department of Pediatrics, University of Massachusetts Medical School, Worcester Massachusetts, USA
| | - Mai K ElMallah
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Teresa E Lever
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA.,Department of Otolaryngology, University of Missouri, Columbia, Missouri, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
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17
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Munir B, Murphy EK, Mallick A, Gutierrez H, Zhang F, Verga S, Smith C, Levy S, McIlduff C, Sarbesh P, Halter RJ, Rutkove SB. A robust and novel electrical impedance metric of pulmonary function in ALS patients. Physiol Meas 2020; 41:044005. [PMID: 32240997 DOI: 10.1088/1361-6579/ab85cf] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Pulmonary function tests (PFTs) are important for assessing respiratory function in amyotrophic lateral sclerosis (ALS) patients. However, weakness of oral and glottal closure, due to concomitant bulbar dysfunction, may result in unreliable PFT values stemming from leakage of air around the breathing tube and through the glottis. In this study, we assessed whether standard thoracic electrical impedance tomography (EIT) could serve as a surrogate measure for PFTs. APPROACH Thoracic EIT was performed simultaneously with standard PFTs on seven ALS patients without clinical bulbar weakness (six men and one woman, mean age of 63 years) and ten healthy volunteers (seven men and three women, mean age of 57 years). A raw impedance metric along with more standard EIT measures were computed and correlated with the normalized forced vital capacity (FVC). Additionally, test/re-test metrics and EIT images were analyzed. MAIN RESULTS The impedance metric was found to be robust and sensitive to lung activity. We also identified qualitative EIT differences between healthy volunteers and ALS patients, with the ALS images showing greater heterogeneity. Significant correlations with FVC were found for both impedance and EIT metrics in ALS patients (r2 = 0.89) and for the impedance metric only in healthy volunteers (r2 = 0.49). SIGNIFICANCE This suggests that EIT, using our novel impedance metric, has the potential to serve as an alternative technology to standard PFTs for assessing pulmonary function in patients with ALS, offering new metrics of disease status for those with bulbar weakness.
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Affiliation(s)
- Badria Munir
- Department of Neurology, Beth Israel Deaconess Medical Center (BIDMC), Boston, MA 02215, United States of America. Harvard Medical School, Boston, MA 02115, United States of America
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18
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Fields DP, Roberts BM, Simon AK, Judge AR, Fuller DD, Mitchell GS. Cancer cachexia impairs neural respiratory drive in hypoxia but not hypercapnia. J Cachexia Sarcopenia Muscle 2019; 10:63-72. [PMID: 30362273 PMCID: PMC6438337 DOI: 10.1002/jcsm.12348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 07/26/2018] [Accepted: 08/19/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Cancer cachexia is an insidious process characterized by muscle atrophy with associated motor deficits, including diaphragm weakness and respiratory insufficiency. Although neuropathology contributes to muscle wasting and motor deficits in many clinical disorders, neural involvement in cachexia-linked respiratory insufficiency has not been explored. METHODS We first used whole-body plethysmography to assess ventilatory responses to hypoxic and hypercapnic chemoreflex activation in mice inoculated with the C26 colon adenocarcinoma cell line. Mice were exposed to a sequence of inspired gas mixtures consisting of (i) air, (ii) hypoxia (11% O2 ) with normocapnia, (iii) hypercapnia (7% CO2 ) with normoxia, and (iv) combined hypercapnia with hypoxia (i.e. maximal chemoreflex response). We also tested the respiratory neural network directly by recording inspiratory burst output from ligated phrenic nerves, thereby bypassing influences from changes in diaphragm muscle strength, respiratory mechanics, or compensation through recruitment of accessory motor pools. RESULTS Cachectic mice demonstrated a significant attenuation of the hypoxic tidal volume (0.26mL±0.01mL vs 0.30mL±0.01mL; p<0.05), breathing frequency (317±10bpm vs 344±6bpm; p<0.05) and phrenic nerve (29.5±2.6% vs 78.8±11.8%; p<0.05) responses. On the other hand, the much larger hypercapnic tidal volume (0.46±0.01mL vs 0.46±0.01mL; p>0.05), breathing frequency (392±5bpm vs 408±5bpm; p>0.05) and phrenic nerve (93.1±8.8% vs 111.1±13.2%; p>0.05) responses were not affected. Further, the concurrent hypercapnia/hypoxia tidal volume (0.45±0.01mL vs 0.45±0.01mL; p>0.05), breathing frequency (395±7bpm vs 400±3bpm; p>0.05), and phrenic nerve (106.8±7.1% vs 147.5±38.8%; p>0.05) responses were not different between C26 cachectic and control mice. CONCLUSIONS Breathing deficits associated with cancer cachexia are specific to the hypoxic ventilatory response and, thus, reflect disruptions in the hypoxic chemoafferent neural network. Diagnostic techniques that detect decompensation and therapeutic approaches that support the failing hypoxic respiratory response may benefit patients at risk for cancer cachectic-associated respiratory failure.
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Affiliation(s)
- Daryl P Fields
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Brandon M Roberts
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Alec K Simon
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Andrew R Judge
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - David D Fuller
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Gordon S Mitchell
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
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19
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Seven YB, Mitchell GS. Mechanisms of compensatory plasticity for respiratory motor neuron death. Respir Physiol Neurobiol 2019; 265:32-39. [PMID: 30625378 DOI: 10.1016/j.resp.2019.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/22/2018] [Accepted: 01/03/2019] [Indexed: 02/06/2023]
Abstract
Respiratory motor neuron death arises from multiple neurodegenerative and traumatic neuromuscular disorders. Despite motor neuron death, compensatory mechanisms minimize its functional impact by harnessing intrinsic mechanisms of compensatory respiratory plasticity. However, the capacity for compensation eventually reaches limits and pathology ensues. Initially, challenges to the system such as increased metabolic demand reveal sub-clinical pathology. With greater motor neuron loss, the eventual result is de-compensation, ventilatory failure, ventilator dependence and then death. In this brief review, we discuss recent advances in our understanding of mechanisms giving rise to compensatory respiratory plasticity in response to respiratory motor neuron death including: 1) increased central respiratory drive, 2) plasticity in synapses on spared phrenic motor neurons, 3) enhanced neuromuscular transmission and 4) shifts in respiratory muscle utilization from more affected to less affected motor pools. Some of these compensatory mechanisms may prolong breathing function, but hasten the demise of surviving motor neurons. Improved understanding of these mechanisms and their impact on survival of spared motor neurons will guide future efforts to develop therapeutic interventions that preserve respiratory function with neuromuscular injury/disease.
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Affiliation(s)
- Yasin B Seven
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA
| | - Gordon S Mitchell
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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20
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Malik R, Meng H, Wongkongkathep P, Corrales CI, Sepanj N, Atlasi RS, Klärner FG, Schrader T, Spencer MJ, Loo JA, Wiedau M, Bitan G. The molecular tweezer CLR01 inhibits aberrant superoxide dismutase 1 (SOD1) self-assembly in vitro and in the G93A-SOD1 mouse model of ALS. J Biol Chem 2019; 294:3501-3513. [PMID: 30602569 DOI: 10.1074/jbc.ra118.005940] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/01/2019] [Indexed: 12/13/2022] Open
Abstract
Mutations in superoxide dismutase 1 (SOD1) cause 15-20% of familial amyotrophic lateral sclerosis (fALS) cases. The resulting amino acid substitutions destabilize SOD1's protein structure, leading to its self-assembly into neurotoxic oligomers and aggregates, a process hypothesized to cause the characteristic motor-neuron degeneration in affected individuals. Currently, effective disease-modifying therapy is not available for ALS. Molecular tweezers prevent formation of toxic protein assemblies, yet their protective action has not been tested previously on SOD1 or in the context of ALS. Here, we tested the molecular tweezer CLR01-a broad-spectrum inhibitor of the self-assembly and toxicity of amyloid proteins-as a potential therapeutic agent for ALS. Using recombinant WT and mutant SOD1, we found that CLR01 inhibited the aggregation of all tested SOD1 forms in vitro Next, we examined whether CLR01 could prevent the formation of misfolded SOD1 in the G93A-SOD1 mouse model of ALS and whether such inhibition would have a beneficial therapeutic effect. CLR01 treatment decreased misfolded SOD1 in the spinal cord significantly. However, these histological findings did not correlate with improvement of the disease phenotype. A small, dose-dependent decrease in disease duration was found in CLR01-treated mice, relative to vehicle-treated animals, yet motor function did not improve in any of the treatment groups. These results demonstrate that CLR01 can inhibit SOD1 misfolding and aggregation both in vitro and in vivo, but raise the question whether such inhibition is sufficient for achieving a therapeutic effect. Additional studies in other less aggressive ALS models may be needed to determine the therapeutic potential of this approach.
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Affiliation(s)
- Ravinder Malik
- From the Department of Neurology, David Geffen School of Medicine, and
| | - Helen Meng
- From the Department of Neurology, David Geffen School of Medicine, and
| | | | | | - Niki Sepanj
- From the Department of Neurology, David Geffen School of Medicine, and
| | - Ryan S Atlasi
- From the Department of Neurology, David Geffen School of Medicine, and
| | | | - Thomas Schrader
- the Faculty of Chemistry, University of Duisburg-Essen, 47057 Essen, Germany
| | - Melissa J Spencer
- From the Department of Neurology, David Geffen School of Medicine, and.,Brain Research Institute, and
| | - Joseph A Loo
- Departments of Chemistry and Biochemistry and.,Biological Chemistry.,Molecular Biology Institute, UCLA, Los Angeles, California 90095 and
| | - Martina Wiedau
- From the Department of Neurology, David Geffen School of Medicine, and .,Brain Research Institute, and
| | - Gal Bitan
- From the Department of Neurology, David Geffen School of Medicine, and .,Brain Research Institute, and.,Molecular Biology Institute, UCLA, Los Angeles, California 90095 and
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21
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Fusco AF, McCall AL, Dhindsa JS, Pucci LA, Strickland LM, Kahn AF, ElMallah MK. The Respiratory Phenotype of Rodent Models of Amyotrophic Lateral Sclerosis and Spinocerebellar Ataxia. JOURNAL OF NEUROINFLAMMATION AND NEURODEGENERATIVE DISEASES 2019; 3:100011. [PMID: 31893284 PMCID: PMC6938301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia (SCA) are neurodegenerative disorders that result in progressive motor dysfunction and ultimately lead to respiratory failure. Rodent models of neurodegenerative disorders provide a means to study the respiratory motor unit pathology that results in respiratory failure. In addition, they are important for pre-clinical studies of novel therapies that improve breathing, quality of life, and survival. The goal of this review is to compare the respiratory phenotype of two neurodegenerative disorders that have different pathological origins, but similar physiological outcomes. Manuscripts reviewed were identified using specific search terms and exclusion criteria. We excluded manuscripts that investigated novel therapeutics and only included those manuscripts that describe the respiratory pathology. The ALS manuscripts describe pathology in respiratory physiology, the phrenic and hypoglossal motor units, respiratory neural control centers, and accessory respiratory muscles. The SCA rodent model manuscripts characterized pathology in overall respiratory function, phrenic motor units and hypoglossal motor neurons. Overall, a combination of pathology in the respiratory motor units and control centers contribute to devastating respiratory dysfunction.
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Affiliation(s)
- Anna F. Fusco
- Department of Pediatrics, School of Medicine, Duke University, Durham, NC
| | - Angela L. McCall
- Department of Pediatrics, School of Medicine, Duke University, Durham, NC
| | - Justin S. Dhindsa
- Department of Pediatrics, School of Medicine, Duke University, Durham, NC
| | - Logan A. Pucci
- Department of Pediatrics, School of Medicine, Duke University, Durham, NC
| | | | - Amanda F. Kahn
- Department of Pediatrics, School of Medicine, Duke University, Durham, NC
| | - Mai K. ElMallah
- Department of Pediatrics, School of Medicine, Duke University, Durham, NC,Corresponding author: Mai K. ElMallah, Division of Allergy, Immunology and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, NC 27710, USA, Tel: 919-684-3577;
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22
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Sebastião AM, Rei N, Ribeiro JA. Amyotrophic Lateral Sclerosis (ALS) and Adenosine Receptors. Front Pharmacol 2018; 9:267. [PMID: 29713276 PMCID: PMC5911503 DOI: 10.3389/fphar.2018.00267] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/09/2018] [Indexed: 12/11/2022] Open
Abstract
In the present review we discuss the potential involvement of adenosinergic signaling, in particular the role of adenosine receptors, in amyotrophic lateral sclerosis (ALS). Though the literature on this topic is not abundant, the information so far available on adenosine receptors in animal models of ALS highlights the interest to continue to explore the role of these receptors in this neurodegenerative disease. Indeed, all motor neurons affected in ALS are responsive to adenosine receptor ligands but interestingly, there are alterations in pre-symptomatic or early symptomatic stages that mirror those in advanced disease stages. Information starts to emerge pointing toward a beneficial role of A2A receptors (A2AR), most probably at early disease states, and a detrimental role of caffeine, in clear contrast with what occurs in other neurodegenerative diseases. However, some evidence also exists on a beneficial action of A2AR antagonists. It may happen that there are time windows where A2AR prove beneficial and others where their blockade is required. Furthermore, the same changes may not occur simultaneously at the different synapses. In line with this, it is not fully understood if ALS is a dying back disease or if it propagates in a centrifugal way. It thus seems crucial to understand how motor neuron dysfunction occurs, how adenosine receptors are involved in those dysfunctions and whether the early changes in purinergic signaling are compensatory or triggers for the disease. Getting this information is crucial before starting the design of purinergic based strategies to halt or delay disease progression.
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Affiliation(s)
- Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal
| | - Nádia Rei
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal
| | - Joaquim A Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal
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23
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Seven YB, Nichols NL, Kelly MN, Hobson OR, Satriotomo I, Mitchell GS. Compensatory plasticity in diaphragm and intercostal muscle utilization in a rat model of ALS. Exp Neurol 2017; 299:148-156. [PMID: 29056361 DOI: 10.1016/j.expneurol.2017.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/29/2017] [Accepted: 10/17/2017] [Indexed: 12/13/2022]
Abstract
In SOD1G93A transgenic rat model of ALS, breathing capacity is preserved until late in disease progression despite profound respiratory motor neuron (MN) cell death. To explore mechanisms preserving breathing capacity, we assessed inspiratory EMG activity in diaphragm and external intercostal T2 (EIC2) and T5 (EIC5) muscles in anesthetized SOD1G93A rats at disease end-stage (20% decrease in body mass). We hypothesized that despite significant phrenic motor neuron loss and decreased phrenic nerve activity, diaphragm electrical activity and trans-diaphragmatic pressure (Pdi) are maintained to sustain ventilation. We alternatively hypothesized that EIC activity is enhanced, compensating for impaired diaphragm function. Diaphragm, EIC2 and EIC5 muscle EMGs and Pdi were measured in urethane-anesthetized, spontaneously breathing female SOD1G93A rats versus wild-type littermates during normoxia (arterial PO2 ~90mmHg, PCO2 ~45mmHg), maximal chemoreceptor stimulation (MCS: 10.5% O2/7% CO2), spontaneous augmented breaths and sustained tracheal occlusion. Phrenic MNs were counted in C3-5; T2 and T5 ventrolateral MNs were counted. In end-stage SOD1G93A rats, 29% of phrenic MNs survived (vs. wild-type), yet integrated diaphragm EMG amplitude was normal. Nevertheless, maximal Pdi decreased ~30% vs. wild type (p<0.01) and increased esophageal to gastric pressure ratio (p<0.05), consistent with persistent diaphragm weakness. Despite major T2 and T5 MN death, integrated EIC2 (100% greater than wild type) and EIC5 (300%) EMG amplitudes were increased in mutant rats during normoxia (p<0.01), possibly compensating for decreased Pdi. Thus, despite significant phrenic MN loss, diaphragm EMG activity is maintained; in contrast, Pdi was not, suggesting diaphragm dysfunction. Presumably, increased EIC EMG activity compensated for persistent diaphragm weakness. These adjustments contribute to remarkable preservation of breathing ability despite major respiratory motor neuron death and diaphragm dysfunction.
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Affiliation(s)
- Yasin B Seven
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA; Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Nicole L Nichols
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
| | - Mia N Kelly
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Orinda R Hobson
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Irawan Satriotomo
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Gordon S Mitchell
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA; Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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24
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MacFarlane PM, Vinit S, Mitchell GS. Enhancement of phrenic long-term facilitation following repetitive acute intermittent hypoxia is blocked by the glycolytic inhibitor 2-deoxyglucose. Am J Physiol Regul Integr Comp Physiol 2017; 314:R135-R144. [PMID: 29021191 DOI: 10.1152/ajpregu.00306.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Moderate acute intermittent hypoxia (mAIH) elicits a form of respiratory motor plasticity known as phrenic long-term facilitation (pLTF). Preconditioning with modest protocols of chronic intermittent hypoxia enhances pLTF, demonstrating pLTF metaplasticity. Since "low-dose" protocols of repetitive acute intermittent hypoxia (rAIH) show promise as a therapeutic modality to restore respiratory (and nonrespiratory) motor function in clinical disorders with compromised breathing, we tested 1) whether preconditioning with a mild rAIH protocol enhances pLTF and hypoglossal (XII) LTF and 2) whether the enhancement is regulated by glycolytic flux. In anesthetized, paralyzed, and ventilated adult male Lewis rats, mAIH (three 5-min episodes of 10% O2) elicited pLTF (pLTF at 60 min post-mAIH: 49 ± 5% baseline). rAIH preconditioning (ten 5-min episodes of 11% O2/day with 5-min normoxic intervals, 3 times per week, for 4 wk) significantly enhanced pLTF (100 ± 16% baseline). XII LTF was unaffected by rAIH. When glycolytic flux was inhibited by 2-deoxy-d-glucose (2-DG) administered via drinking water (~80 mg·kg-1·day-1), pLTF returned to normal levels (58 ± 8% baseline); 2-DG had no effect on pLTF in normoxia-pretreated rats (59 ± 7% baseline). In ventral cervical (C4/5) spinal homogenates, rAIH increased inducible nitric oxide synthase mRNA vs. normoxic controls, an effect blocked by 2-DG. However, there were no detectable effects of rAIH or 2-DG on several molecules associated with phrenic motor plasticity, including serotonin 2A, serotonin 7, brain-derived neurotrophic factor, tropomyosin receptor kinase B, or VEGF mRNA. We conclude that modest, but prolonged, rAIH elicits pLTF metaplasticity and that a drug known to inhibit glycolytic flux (2-DG) blocks pLTF enhancement.
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Affiliation(s)
- P M MacFarlane
- Department of Comparative Biosciences, University of Wisconsin , Madison, Wisconsin.,Department of Pediatrics, Case Western Reserve University, Rainbow Babies & Children's Hospital , Cleveland, Ohio
| | - S Vinit
- Department of Comparative Biosciences, University of Wisconsin , Madison, Wisconsin.,Université de Versailles Saint-Quentin-en-Yvelines, INSERM U1179 END-ICAP, UFR des Sciences de la Santé-Simone Veil, Montigny-le-Bretonneux, France
| | - G S Mitchell
- Department of Comparative Biosciences, University of Wisconsin , Madison, Wisconsin.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida , Gainesville, Florida
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25
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Agosto-Marlin IM, Mitchell GS. Spinal BDNF-induced phrenic motor facilitation requires PKCθ activity. J Neurophysiol 2017; 118:2755-2762. [PMID: 28855298 DOI: 10.1152/jn.00945.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 07/19/2017] [Accepted: 08/29/2017] [Indexed: 11/22/2022] Open
Abstract
Spinal brain-derived neurotrophic factor (BDNF) is necessary and sufficient for certain forms of long-lasting phrenic motor facilitation (pMF). BDNF elicits pMF by binding to its high-affinity receptor, tropomyosin receptor kinase B (TrkB), on phrenic motor neurons, potentially activating multiple downstream signaling cascades. Canonical BDNF/TrkB signaling includes the 1) Ras/RAF/MEK/ERK MAP kinase, 2) phosphatidylinositol 3-kinase (PI3K)/Akt, and 3) PLCγ/PKC pathways. Here we demonstrate that spinal BDNF-induced pMF requires PLCγ/PKCθ in normal rats but not MEK/ERK or PI3K/Akt signaling. Cervical intrathecal injections of MEK/ERK (U0126) or PI3K/Akt (PI-828; 100 μM, 12 μl) inhibitor had no effect on BDNF-induced pMF (90 min after BDNF; U0126 + BDNF: 59 ± 14%, PI-828 + BDNF: 59 ± 8%, inhibitor vehicle + BDNF: 56 ± 7%; all P ≥ 0.05). In contrast, PKCθ inhibition with theta inhibitory peptide (TIP; 0.86 mM, 12 μl) prevented BDNF-induced pMF (90 min after BDNF; TIP + BDNF: -2 ± 2%; P ≤ 0.05 vs. other groups). Thus BDNF-induced pMF requires downstream PLCγ/PKCθ signaling, contrary to initial expectations.NEW AND NOTEWORTHY We demonstrate that BDNF-induced pMF requires downstream signaling via PKCθ but not MEK/ERK or PI3K/Akt signaling. These data are essential to understand the sequence of the cellular cascade leading to BDNF-dependent phrenic motor plasticity.
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Affiliation(s)
- Ibis M Agosto-Marlin
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin; and
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin; and .,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, Florida
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26
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Nichols NL, Craig TA, Tanner MA. Phrenic long-term facilitation following intrapleural CTB-SAP-induced respiratory motor neuron death. Respir Physiol Neurobiol 2017; 256:43-49. [PMID: 28822818 DOI: 10.1016/j.resp.2017.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/20/2017] [Accepted: 08/04/2017] [Indexed: 01/26/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating disease leading to progressive motor neuron degeneration and death by ventilatory failure. In a rat model of ALS (SOD1G93A), phrenic long-term facilitation (pLTF) following acute intermittent hypoxia (AIH) is enhanced greater than expected at disease end-stage but the mechanism is unknown. We suggest that one trigger for this enhancement is motor neuron death itself. Intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) selectively kill respiratory motor neurons and mimic motor neuron death observed in SOD1G93A rats. This CTB-SAP model allows us to study the impact of respiratory motor neuron death on breathing without many complications attendant to ALS. Here, we tested the hypothesis that phrenic motor neuron death is sufficient to enhance pLTF. pLTF was assessed in anesthetized, paralyzed and ventilated Sprague Dawley rats 7 and 28 days following bilateral intrapleural injections of: 1) CTB-SAP (25 μg), or 2) un-conjugated CTB and SAP (control). CTB-SAP enhanced pLTF at 7 (CTB-SAP: 162 ± 18%, n = 8 vs. Control: 63 ± 3%; n = 8; p < 0.05), but not 28 days post-injection (CTB-SAP: 64 ± 10%, n = 10 vs. Control: 60 ± 13; n = 8; p > 0.05). Thus, pLTF at 7 (not 28) days post-CTB-SAP closely resembles pLTF in end-stage ALS rats, suggesting that processes unique to the early period of motor neuron death enhance pLTF. This project increases our understanding of respiratory plasticity and its implications for breathing in motor neuron disease.
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Affiliation(s)
- Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, 65211, United States.
| | - Taylor A Craig
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, 65211, United States
| | - Miles A Tanner
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, 65211, United States
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27
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Lanfranconi F, Ferri A, Corna G, Bonazzi R, Lunetta C, Silani V, Riva N, Rigamonti A, Maggiani A, Ferrarese C, Tremolizzo L. Inefficient skeletal muscle oxidative function flanks impaired motor neuron recruitment in Amyotrophic Lateral Sclerosis during exercise. Sci Rep 2017; 7:2951. [PMID: 28592858 PMCID: PMC5462750 DOI: 10.1038/s41598-017-02811-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/19/2017] [Indexed: 12/11/2022] Open
Abstract
This study aimed to evaluate muscle oxidative function during exercise in amyotrophic lateral sclerosis patients (pALS) with non-invasive methods in order to assess if determinants of reduced exercise tolerance might match ALS clinical heterogeneity. 17 pALS, who were followed for 4 months, were compared with 13 healthy controls (CTRL). Exercise tolerance was assessed by an incremental exercise test on cycle ergometer measuring peak O2 uptake (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{{\rm{V}}}$$\end{document}V˙O2peak), vastus lateralis oxidative function by near infrared spectroscopy (NIRS) and breathing pattern (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{{\rm{V}}}$$\end{document}V˙E peak). pALS displayed: (1) 44% lower \documentclass[12pt]{minimal}
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\begin{document}$$\dot{{\rm{V}}}$$\end{document}V˙O2peakvs. CTRL (p < 0.0001), paralleled by a 43% decreased peak skeletal muscle oxidative function (p < 0.01), with a linear regression between these two variables (r2 = 0.64, p < 0.0001); (2) 46% reduced \documentclass[12pt]{minimal}
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\begin{document}$$\dot{{\rm{V}}}$$\end{document}V˙Epeakvs. CTRL (p < 0.0001), achieved by using an inefficient breathing pattern (increasing respiratory frequency) from the onset until the end of exercise. Inefficient skeletal muscle O2 function, when flanking the impaired motor units recruitment, is a major determinant of pALS clinical heterogeneity and working capacity exercise tolerance. CPET and NIRS are useful tools for detecting early stages of oxidative deficiency in skeletal muscles, disclosing individual impairments in the O2 transport and utilization chain.
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Affiliation(s)
- F Lanfranconi
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milano, Italy.
| | - A Ferri
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milano, Italy.,Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia
| | - G Corna
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milano, Italy
| | - R Bonazzi
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milano, Italy
| | - C Lunetta
- NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milano, Italy
| | - V Silani
- Department of Neurology and Laboratory Neuroscience - IRCCS Istituto Auxologico Italiano, Pioltello, Italy.,Department of Pathophysiology and Transplantation, Dino Ferrari Centre, Università of Milan, Milano, Italy
| | - N Riva
- San Raffaele Hospital, Milano, Italy
| | | | - A Maggiani
- Italian Academy of Osteopathic Medicine (AIMO), Saronno, Italy
| | - C Ferrarese
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milano, Italy.,Neurology Unit, "San Gerardo" Hospital, Monza, Italy
| | - L Tremolizzo
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milano, Italy.,Neurology Unit, "San Gerardo" Hospital, Monza, Italy
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28
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Hinchcliffe M, Smith A. Riluzole: real-world evidence supports significant extension of median survival times in patients with amyotrophic lateral sclerosis. Degener Neurol Neuromuscul Dis 2017; 7:61-70. [PMID: 30050378 PMCID: PMC6053101 DOI: 10.2147/dnnd.s135748] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the commonest form of motor neuron disease and is a fatal, degenerative, multisystem disorder affecting upper and/or lower motor neurons in the motor cortex, brain stem, and spinal cord. ALS is characterized by progressive atrophy of associated bulbar, limb, thoracic, and abdominal muscles and supporting cells manifesting in a range of muscular symptoms such as weakness and wasting and eventual paralysis; the majority of patients will die from respiratory failure within 2–5 years of onset. Riluzole, a synthetic benzothiazole drug with glutamine antagonist activity, is indicated for the treatment of patients with ALS and is the only drug that has been shown to slow the course of the disease and extend survival in ALS patients. The original analyses, and subsequent meta-analyses, of data obtained from randomized controlled trials (RCTs) suggest that riluzole typically extends survival by 2–3 months and increases the chance of an additional year of survival by ~9%. However, published real-world evidence (RWE) from 10 clinical ALS databases indicates that riluzole therapy may afford much greater extension of survival, and improvements in median survival times of more than 19 months have been reported in the overall ALS patient population. This article will review the available data from RCTs and RWE on riluzole therapy.
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Affiliation(s)
| | - Alan Smith
- PharmaSci Consulting Ltd, Nottingham, UK
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29
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30
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Respiratory neuroplasticity – Overview, significance and future directions. Exp Neurol 2017; 287:144-152. [DOI: 10.1016/j.expneurol.2016.05.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 05/17/2016] [Indexed: 01/10/2023]
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31
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Fields DP, Mitchell GS. Divergent cAMP signaling differentially regulates serotonin-induced spinal motor plasticity. Neuropharmacology 2016; 113:82-88. [PMID: 27663700 DOI: 10.1016/j.neuropharm.2016.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 12/29/2022]
Abstract
Spinal metabotropic serotonin receptors encode transient experiences into long-lasting changes in motor behavior (i.e. motor plasticity). While interactions between serotonin receptor subtypes are known to regulate plasticity, the significance of molecular divergence in downstream G protein coupled receptor signaling is not well understood. Here we tested the hypothesis that distinct cAMP dependent signaling pathways differentially regulate serotonin-induced phrenic motor facilitation (pMF); a well-studied model of spinal motor plasticity. Specifically, we studied the capacity of cAMP-dependent protein kinase A (PKA) and exchange protein activated by cAMP (EPAC) to regulate 5-HT2A receptor-induced pMF within adult male rats. Although spinal PKA, EPAC and 5-HT2A each elicit pMF when activated alone, concurrent PKA and 5-HT2A activation interact via mutual inhibition thereby blocking pMF expression. Conversely, concurrent EPAC and 5-HT2A activation enhance pMF expression reflecting additive contributions from both mechanisms. Thus, we demonstrate that distinct downstream cAMP signaling pathways enable differential regulation of 5-HT2A-induced pMF. Conditional activation of independent signaling mechanisms may explain experience amendable changes in plasticity expression (i.e. metaplasticity), an emerging concept thought to enable flexible motor control within the adult central nervous system.
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Affiliation(s)
- D P Fields
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706, USA
| | - G S Mitchell
- Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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32
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Romer SH, Seedle K, Turner SM, Li J, Baccei ML, Crone SA. Accessory respiratory muscles enhance ventilation in ALS model mice and are activated by excitatory V2a neurons. Exp Neurol 2016; 287:192-204. [PMID: 27456268 DOI: 10.1016/j.expneurol.2016.05.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 05/09/2016] [Accepted: 05/26/2016] [Indexed: 02/06/2023]
Abstract
Inspiratory accessory respiratory muscles (ARMs) enhance ventilation when demands are high, such as during exercise and/or pathological conditions. Despite progressive degeneration of phrenic motor neurons innervating the diaphragm, amyotrophic lateral sclerosis (ALS) patients and rodent models are able to maintain ventilation at early stages of disease. In order to assess the contribution of ARMs to respiratory compensation in ALS, we examined the activity of ARMs and ventilation throughout disease progression in SOD1G93A ALS model mice at rest using a combination of electromyography and unrestrained whole body plethysmography. Increased ARM activity, accompanied by increased ventilation, is observed beginning at the onset of symptoms. However, ARM recruitment fails to occur at rest at late stages of disease, even though the same ARMs are used for other behaviors. Using a chemogenetic approach, we demonstrate that a glutamatergic class of neurons in the brainstem and spinal cord, the V2a class, is sufficient to drive increased ARM activity at rest in healthy mice. Additionally, we reveal pathology in the medial reticular formation of the brainstem of SOD1G93A mice using immunohistochemistry and confocal imaging. Both spinal and brainstem V2a neurons degenerate in ALS model mice, accompanied by regional activation of astrocytes and microglia. These results establish inspiratory ARM recruitment as one of the compensatory mechanisms that maintains breathing at early stages of disease and indicate that V2a neuron degeneration may contribute to ARM failure at late stages of disease.
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Affiliation(s)
- Shannon H Romer
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229
| | - Kari Seedle
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229
| | - Sarah M Turner
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229
| | - Jie Li
- Pain Research Center, Dept. of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267
| | - Mark L Baccei
- Pain Research Center, Dept. of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267
| | - Steven A Crone
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229; Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229.
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33
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Pattinson KTS, Turner MR. A wider pathological network underlying breathlessness and respiratory failure in amyotrophic lateral sclerosis. Eur Respir J 2016; 47:1632-4. [PMID: 27246080 DOI: 10.1183/13993003.00321-2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 03/04/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Kyle T S Pattinson
- Nuffield Dept of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Martin R Turner
- Nuffield Dept of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Georges M, Morawiec E, Raux M, Gonzalez-Bermejo J, Pradat PF, Similowski T, Morélot-Panzini C. Cortical drive to breathe in amyotrophic lateral sclerosis: a dyspnoea-worsening defence? Eur Respir J 2016; 47:1818-28. [DOI: 10.1183/13993003.01686-2015] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 01/19/2016] [Indexed: 11/05/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease causing diaphragm weakness that can be partially compensated by inspiratory neck muscle recruitment. This disappears during sleep, which is compatible with a cortical contribution to the drive to breathe. We hypothesised that ALS patients with respiratory failure exhibit respiratory-related cortical activity, relieved by noninvasive ventilation (NIV) and related to dyspnoea.We studied 14 ALS patients with respiratory failure. Electroencephalographic recordings (EEGs) and electromyographic recordings of inspiratory neck muscles were performed during spontaneous breathing and NIV. Dyspnoea was evaluated using the Multidimensional Dyspnea Profile.Eight patients exhibited slow EEG negativities preceding inspiration (pre-inspiratory potentials) during spontaneous breathing. Pre-inspiratory potentials were attenuated during NIV (p=0.04). Patients without pre-inspiratory potentials presented more advanced forms of ALS and more severe respiratory impairment, but less severe dyspnoea. Patients with pre-inspiratory potentials had stronger inspiratory neck muscle activation and more severe dyspnoea during spontaneous breathing.ALS-related diaphragm weakness can engage cortical resources to augment the neural drive to breathe. This might reflect a compensatory mechanism, with the intensity of dyspnoea a negative consequence. Disease progression and the corresponding neural loss could abolish this phenomenon. A putative cognitive cost should be investigated.
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Breathing pattern in a phase I clinical trial of intraspinal injection of autologous bone marrow mononuclear cells in patients with amyotrophic lateral sclerosis. Respir Physiol Neurobiol 2016; 221:54-8. [DOI: 10.1016/j.resp.2015.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/19/2015] [Accepted: 11/12/2015] [Indexed: 11/20/2022]
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Nichols NL, Satriotomo I, Harrigan DJ, Mitchell GS. Acute intermittent hypoxia induced phrenic long-term facilitation despite increased SOD1 expression in a rat model of ALS. Exp Neurol 2015; 273:138-50. [PMID: 26287750 DOI: 10.1016/j.expneurol.2015.08.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 02/08/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease characterized by motor neuron death. Since most ALS patients succumb to ventilatory failure from loss of respiratory motor neurons, any effective ALS treatment must preserve and/or restore breathing capacity. In rats over-expressing mutated super-oxide dismutase-1 (SOD1(G93A)), the capacity to increase phrenic motor output is decreased at disease end-stage, suggesting imminent ventilatory failure. Acute intermittent hypoxia (AIH) induces phrenic long-term facilitation (pLTF), a form of spinal respiratory motor plasticity with potential to restore phrenic motor output in clinical disorders that compromise breathing. Since pLTF requires NADPH oxidase activity and reactive oxygen species (ROS) formation, it is blocked by NADPH oxidase inhibition and SOD mimetics in normal rats. Thus, we hypothesized that SOD1(G93A) (mutant; MT) rats do not express AIH-induced pLTF due to over-expression of active mutant superoxide dismutase-1. AIH-induced pLTF and hypoglossal (XII) LTF were assessed in young, pre-symptomatic and end-stage anesthetized MT rats and age-matched wild-type littermates. Contrary to predictions, pLTF and XII LTF were observed in MT rats at all ages; at end-stage, pLTF was actually enhanced. SOD1 levels were elevated in young and pre-symptomatic MT rats, yet superoxide accumulation in putative phrenic motor neurons (assessed with dihydroethidium) was unchanged; however, superoxide accumulation significantly decreased at end-stage. Thus, compensatory mechanisms appear to maintain ROS homoeostasis until late in disease progression, preserving AIH-induced respiratory plasticity. Following intrathecal injections of an NADPH oxidase inhibitor (apocynin; 600 μM; 12 μL), pLTF was abolished in pre-symptomatic, but not end-stage MT rats, demonstrating that pLTF is NADPH oxidase dependent in pre-symptomatic, but NADPH oxidase independent in end-stage MT rats. Mechanisms preserving/enhancing the capacity for pLTF in MT rats are not known.
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Affiliation(s)
- Nicole L Nichols
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Irawan Satriotomo
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Daniel J Harrigan
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
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Identification of unexpected respiratory abnormalities in patients with amyotrophic lateral sclerosis through electromyographic analysis using intramuscular electrodes implanted for therapeutic diaphragmatic pacing. Am J Surg 2015; 209:451-6. [DOI: 10.1016/j.amjsurg.2014.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/30/2014] [Accepted: 10/01/2014] [Indexed: 11/22/2022]
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Fields DP, Mitchell GS. Spinal metaplasticity in respiratory motor control. Front Neural Circuits 2015; 9:2. [PMID: 25717292 PMCID: PMC4324138 DOI: 10.3389/fncir.2015.00002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 01/07/2015] [Indexed: 12/25/2022] Open
Abstract
A hallmark feature of the neural system controlling breathing is its ability to exhibit plasticity. Less appreciated is the ability to exhibit metaplasticity, a change in the capacity to express plasticity (i.e., “plastic plasticity”). Recent advances in our understanding of cellular mechanisms giving rise to respiratory motor plasticity lay the groundwork for (ongoing) investigations of metaplasticity. This detailed understanding of respiratory metaplasticity will be essential as we harness metaplasticity to restore breathing capacity in clinical disorders that compromise breathing, such as cervical spinal injury, motor neuron disease and other neuromuscular diseases. In this brief review, we discuss key examples of metaplasticity in respiratory motor control, and our current understanding of mechanisms giving rise to spinal plasticity and metaplasticity in phrenic motor output; particularly after pre-conditioning with intermittent hypoxia. Progress in this area has led to the realization that similar mechanisms are operative in other spinal motor networks, including those governing limb movement. Further, these mechanisms can be harnessed to restore respiratory and non-respiratory motor function after spinal injury.
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Affiliation(s)
- Daryl P Fields
- Department of Comparative Biosciences, University of Wisconsin-Madison Madison, WI, USA
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin-Madison Madison, WI, USA
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Respiratory function after selective respiratory motor neuron death from intrapleural CTB-saporin injections. Exp Neurol 2014; 267:18-29. [PMID: 25476493 DOI: 10.1016/j.expneurol.2014.11.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/26/2014] [Accepted: 11/20/2014] [Indexed: 02/06/2023]
Abstract
UNLABELLED Amyotrophic lateral sclerosis (ALS) causes progressive motor neuron degeneration, paralysis and death by ventilatory failure. In rodent ALS models: 1) breathing capacity is preserved until late in disease progression despite major respiratory motor neuron death, suggesting unknown forms of compensatory respiratory plasticity; and 2) spinal microglia become activated in association with motor neuron cell death. Here, we report a novel experimental model to study the impact of respiratory motor neuron death on compensatory responses without many complications attendant to spontaneous motor neuron disease. In specific, we used intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) to selectively kill motor neurons with access to the pleural space. Motor neuron survival, CD11b labeling (microglia), ventilatory capacity and phrenic motor output were assessed in rats 3-28days after intrapleural injections of: 1) CTB-SAP (25 and 50μg), or 2) unconjugated CTB and SAP (i.e. control; (CTB+SAP). CTB-SAP elicited dose-dependent phrenic and intercostal motor neuron death; 7days post-25μg CTB-SAP, motor neuron survival approximated that in end-stage ALS rats (phrenic: 36±7%; intercostal: 56±10% of controls; n=9; p<0.05). CTB-SAP caused minimal cell death in other brainstem or spinal cord regions. CTB-SAP 1) increased CD11b fractional area in the phrenic motor nucleus, indicating microglial activation; 2) decreased breathing during maximal chemoreceptor stimulation; and 3) diminished phrenic motor output in anesthetized rats (7days post-25μg, CTB-SAP 0.3±0.07V; CTB+SAP: 1.5±0.3; n=9; p<0.05). Intrapleural CTB-SAP represents a novel, inducible model of respiratory motor neuron death and provides an opportunity to study compensation for respiratory motor neuron loss.
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Nichols NL, Johnson RA, Satriotomo I, Mitchell GS. Neither serotonin nor adenosine-dependent mechanisms preserve ventilatory capacity in ALS rats. Respir Physiol Neurobiol 2014; 197:19-28. [PMID: 24681328 DOI: 10.1016/j.resp.2014.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 03/13/2014] [Accepted: 03/15/2014] [Indexed: 02/04/2023]
Abstract
In rats over-expressing SOD1G93A, ventilation is preserved despite significant loss of respiratory motor neurons. Thus, unknown forms of compensatory respiratory plasticity may offset respiratory motor neuron cell death. Although mechanisms of such compensation are unknown, other models of respiratory motor plasticity may provide a conceptual guide. Multiple cellular mechanisms give rise to phrenic motor facilitation; one mechanism requires spinal serotonin receptor and NADPH oxidase activity whereas another requires spinal adenosine receptor activation. Here, we studied whether these mechanisms contribute to compensatory respiratory plasticity in SOD1G93A rats. Using plethysmography, we assessed ventilation in end-stage SOD1G93A rats after: (1) serotonin depletion with parachlorophenylalanine (PCPA), (2) serotonin (methysergide) and A2A (MSX-3) receptor inhibition, (3) NADPH oxidase inhibition (apocynin), and (4) combined treatments. The ability to increase ventilation was not decreased by individual or combined treatments; thus, these mechanisms do not maintain breathing capacity at end-stage motor neuron disease. Possible mechanisms giving rise to enhanced breathing capacity with combined treatment in end-stage SOD1G93A rats are discussed.
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Affiliation(s)
- N L Nichols
- Department of Comparative Biosciences, University of Wisconsin, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, United States
| | - R A Johnson
- Department of Surgical Sciences, University of Wisconsin, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, United States
| | - I Satriotomo
- Department of Comparative Biosciences, University of Wisconsin, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, United States
| | - G S Mitchell
- Department of Comparative Biosciences, University of Wisconsin, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, United States.
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Clinical challenges to ventilatory control. Respir Physiol Neurobiol 2013; 189:211-2. [PMID: 24056024 DOI: 10.1016/j.resp.2013.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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