1
|
Ó Murchú SC, O'Halloran KD. BREATHE DMD: boosting respiratory efficacy after therapeutic hypoxic episodes in Duchenne muscular dystrophy. J Physiol 2024. [PMID: 38837229 DOI: 10.1113/jp280280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/12/2024] [Indexed: 06/07/2024] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal genetic neuromuscular disorder, characterised by progressive decline in skeletal muscle function due to the secondary consequences of dystrophin deficiency. Weakness extends to the respiratory musculature, and cardiorespiratory failure is the leading cause of death in men with DMD. Intermittent hypoxia has emerged as a potential therapy to counteract ventilatory insufficiency by eliciting long-term facilitation of breathing. Mechanisms of sensory and motor facilitation of breathing have been well delineated in animal models. Various paradigms of intermittent hypoxia have been designed and implemented in human trials culminating in clinical trials in people with spinal cord injury and amyotrophic lateral sclerosis. Application of therapeutic intermittent hypoxia to DMD is considered together with discussion of the potential barriers to progression owing to the complexity of this devastating disease. Notwithstanding the considerable challenges and potential pitfalls of intermittent hypoxia-based therapies for DMD, we suggest it is incumbent on the research community to explore the potential benefits in pre-clinical models. Intermittent hypoxia paradigms should be implemented to explore the proclivity to express respiratory plasticity with the longer-term aim of preserving and potentiating ventilation in pre-clinical models and people with DMD.
Collapse
Affiliation(s)
- Seán C Ó Murchú
- Department of Physiology, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, University College Cork, Cork, Ireland
| |
Collapse
|
2
|
Lv R, Liu X, Zhang Y, Dong N, Wang X, He Y, Yue H, Yin Q. Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome. Signal Transduct Target Ther 2023; 8:218. [PMID: 37230968 DOI: 10.1038/s41392-023-01496-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.
Collapse
Affiliation(s)
- Renjun Lv
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Xueying Liu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Yue Zhang
- Department of Geriatrics, the 2nd Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
| | - Na Dong
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Xiao Wang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Yao He
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Hongmei Yue
- Department of Pulmonary and Critical Care Medicine, The First Hospital of Lanzhou University, Lanzhou, 730000, China.
| | - Qingqing Yin
- Department of Geriatric Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China.
| |
Collapse
|
3
|
Vaughan S, Sankari A, Carroll S, Eshraghi M, Obiakor H, Yarandi H, Chowdhuri S, Salloum A, Badr MS. Tetraplegia is associated with increased hypoxic ventilatory response during nonrapid eye movement sleep. Physiol Rep 2022; 10:e15455. [PMID: 36065854 PMCID: PMC9446393 DOI: 10.14814/phy2.15455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023] Open
Abstract
People with cervical spinal cord injury (SCI) are likely to experience chronic intermittent hypoxia while sleeping. The physiological effects of intermittent hypoxia on the respiratory system during spontaneous sleep in individuals with chronic cervical SCI are unknown. We hypothesized that individuals with cervical SCI would demonstrate higher short- and long-term ventilatory responses to acute intermittent hypoxia (AIH) exposure than individuals with thoracic SCI during sleep. Twenty participants (10 with cervical SCI [9 male] and 10 with thoracic SCI [6 male]) underwent an AIH and sham protocol during sleep. During the AIH protocol, each participant experienced 15 episodes of isocapnic hypoxia using mixed gases of 100% nitrogen (N2 ) and 40% carbon dioxide (CO2 ) to achieve an oxygen saturation of less than 90%. This was followed by two breaths of 100% oxygen (O2 ). Measurements were collected before, during, and 40 min after the AIH protocol to obtain ventilatory data. During the sham protocol, participants breathed room air for the same amount of time that elapsed during the AIH protocol and at approximately the same time of night. Hypoxic ventilatory response (HVR) during the AIH protocol was significantly higher in participants with cervical SCI than those with thoracic SCI. There was no significant difference in minute ventilation (V.E. ), tidal volume (V.T. ), or respiratory frequency (f) during the recovery period after AIH in cervical SCI compared to thoracic SCI groups. Individuals with cervical SCI demonstrated a significant short-term increase in HVR compared to thoracic SCI. However, there was no evidence of ventilatory long-term facilitation following AIH in either group.
Collapse
Affiliation(s)
- Sarah Vaughan
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Abdulghani Sankari
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
- Department of Medical EducationAscension Providence HospitalSouthfieldMichiganUSA
| | - Sean Carroll
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Mehdi Eshraghi
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Harold Obiakor
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Hossein Yarandi
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Susmita Chowdhuri
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Anan Salloum
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - M. Safwan Badr
- Department of MedicineJohn D. Dingell VA Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Abstract
AbstractThe following review is designed to explore the pathophysiology of sleep apnea in aging women. The review initially introduces four endotypes (i.e., a more collapsible airway, upper airway muscle responsiveness, arousal threshold, and loop gain) that may have a role in the initiation of obstructive sleep apnea. Thereafter, sex differences in the prevalence of sleep apnea are considered along with differences in the prevalence that exist between younger and older women. Following this discussion, we consider how each endotype might contribute to the increase in prevalence of sleep apnea in aging women. Lastly, we address how modifications in one form of respiratory plasticity, long-term facilitation, that might serve to mitigate apneic events in younger women may be modified in aging women with obstructive sleep apnea. Overall, the published literature indicates that the prevalence of sleep apnea is increased in aging women. This increase is linked primarily to a more collapsible airway and possibly to reduced responsiveness of upper airway muscle activity. In contrast, modifications in loop gain or the arousal threshold do not appear to have a role in the increased prevalence of sleep apnea in aging women. Moreover, we suggest that mitigation of long-term facilitation could contribute to the increased prevalence of sleep apnea in aging women.
Collapse
|
6
|
Panza GS, Sutor T, Gee CM, Graco M, McCully KK, Chiodo A, Badr MS, Nash MS. Is Sleep Disordered Breathing Confounding Rehabilitation Outcomes in Spinal Cord Injury Research? Arch Phys Med Rehabil 2021; 103:1034-1045. [PMID: 34537222 DOI: 10.1016/j.apmr.2021.08.015] [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: 08/15/2021] [Accepted: 08/24/2021] [Indexed: 11/02/2022]
Abstract
The purpose of this article is to highlight the importance of considering sleep-disordered breathing (SDB) as a potential confounder to rehabilitation research interventions in spinal cord injury (SCI). SDB is highly prevalent in SCI, with increased prevalence in individuals with higher and more severe lesions, and the criterion standard treatment with continuous positive airway pressure remains problematic. Despite its high prevalence, SDB is often untested and untreated in individuals with SCI. In individuals without SCI, SDB is known to negatively affect physical function and many of the physiological systems that negatively affect physical rehabilitation in SCI. Thus, owing to the high prevalence, under testing, low treatment adherence, and known negative effect on the physical function, it is contended that underdiagnosed SDB in SCI may be confounding physical rehabilitation research studies in individuals with SCI. Studies investigating the effect of treating SDB and its effect on physical rehabilitation in SCI were unable to be located. Thus, studies investigating the likely integrated relationship among physical rehabilitation, SDB, and proper treatment of SDB in SCI are needed. Owing to rapid growth in both sleep medicine and physical rehabilitation intervention research in SCI, the authors contend it is the appropriate time to begin the conversations and collaborations between these fields. We discuss a general overview of SDB and physical training modalities, as well as how SDB could be affecting these studies.
Collapse
Affiliation(s)
- Gino S Panza
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI; Department of Physiology, Wayne State University School of Medicine, Detroit, MI.
| | - Tommy Sutor
- Research Service, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, VA
| | - Cameron M Gee
- International Collaboration on Repair Discoveries, Vancouver, BC, Canada
| | - Marnie Graco
- Institute for Breathing and Sleep, Austin Health; and School of Physiotherapy, University of Melbourne, Melbourne, Australia
| | | | - Anthony Chiodo
- Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI
| | - M Safwan Badr
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI; Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI
| | - Mark S Nash
- Department of Neurological Surgery, Physical Medicine & Rehabiliation, and Physical Therapy, Miami, FL; The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL
| | | |
Collapse
|
7
|
Sutor T, Cavka K, Vose AK, Welch JF, Davenport P, Fuller DD, Mitchell GS, Fox EJ. Single-session effects of acute intermittent hypoxia on breathing function after human spinal cord injury. Exp Neurol 2021; 342:113735. [PMID: 33951477 DOI: 10.1016/j.expneurol.2021.113735] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/14/2021] [Accepted: 04/29/2021] [Indexed: 12/13/2022]
Abstract
After spinal cord injury (SCI) respiratory complications are a leading cause of morbidity and mortality. Acute intermittent hypoxia (AIH) triggers spinal respiratory motor plasticity in rodent models, and repetitive AIH may have the potential to restore breathing capacity in those with SCI. As an initial approach to provide proof of principle for such effects, we tested single-session AIH effects on breathing function in adults with chronic SCI. 17 adults (13 males; 34.1 ± 14.5 years old; 13 motor complete SCI; >6 months post injury) completed two randomly ordered sessions, AIH versus sham. AIH consisted of 15, 1-min episodes (hypoxia: 10.3% O2; sham: 21% O2) interspersed with room air breathing (1.5 min, 21% oxygen); no attempt was made to regulate arterial CO2 levels. Blood oxygen saturation (SpO2), maximal inspiratory and expiratory pressures (MIP; MEP), forced vital capacity (FVC), and mouth occlusion pressure within 0.1 s (P0.1) were assessed. Outcomes were compared using nonparametric Wilcoxon's tests, or a 2 × 2 ANOVA. Baseline SpO2 was 97.2 ± 1.3% and was unchanged during sham experiments. During hypoxic episodes, SpO2 decreased to 84.7 ± 0.9%, and returned to baseline levels during normoxic intervals. Outcomes were unchanged from baseline post-sham. Greater increases in MIP were evident post AIH vs. sham (median values; +10.8 cmH2O vs. -2.6 cmH2O respectively, 95% confidence interval (-18.7) - (-4.3), p = .006) with a moderate Cohen's effect size (0.68). P0.1, MEP and FVC did not change post-AIH. A single AIH session increased maximal inspiratory pressure generation, but not other breathing functions in adults with SCI. Reasons may include greater spared innervation to inspiratory versus expiratory muscles or differences in the capacity for AIH-induced plasticity in inspiratory motor neuron pools. Based on our findings, the therapeutic potential of AIH on breathing capacity in people with SCI warrants further investigation.
Collapse
Affiliation(s)
- Tommy Sutor
- Hunter Holmes McGuire VA Medical Center, United States.
| | - Kathryn Cavka
- Brooks Rehabilitation, Jacksonville, FL, United States.
| | - Alicia K Vose
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.
| | - Joseph F Welch
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.
| | - Paul Davenport
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States; Department of Physiological Sciences, University of Florida, Gainesville, FL, United States.
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.
| | - Gordon S Mitchell
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.
| | - Emily J Fox
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States; Brooks Rehabilitation, Jacksonville, FL, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.
| |
Collapse
|
8
|
Puri S, Panza G, Mateika JH. A comprehensive review of respiratory, autonomic and cardiovascular responses to intermittent hypoxia in humans. Exp Neurol 2021; 341:113709. [PMID: 33781731 PMCID: PMC8527806 DOI: 10.1016/j.expneurol.2021.113709] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/17/2021] [Accepted: 03/24/2021] [Indexed: 01/08/2023]
Abstract
This review explores forms of respiratory and autonomic plasticity, and associated outcome measures, that are initiated by exposure to intermittent hypoxia. The review focuses primarily on studies that have been completed in humans and primarily explores the impact of mild intermittent hypoxia on outcome measures. Studies that have explored two forms of respiratory plasticity, progressive augmentation of the hypoxic ventilatory response and long-term facilitation of ventilation and upper airway muscle activity, are initially reviewed. The role these forms of plasticity might have in sleep disordered breathing are also explored. Thereafter, the role of intermittent hypoxia in the initiation of autonomic plasticity is reviewed and the role this form of plasticity has in cardiovascular and hemodynamic responses during and following intermittent hypoxia is addressed. The role of these responses in individuals with sleep disordered breathing and spinal cord injury are subsequently addressed. Ultimately an integrated picture of the respiratory, autonomic and cardiovascular responses to intermittent hypoxia is presented. The goal of the integrated picture is to address the types of responses that one might expect in humans exposed to one-time and repeated daily exposure to mild intermittent hypoxia. This form of intermittent hypoxia is highlighted because of its potential therapeutic impact in promoting functional improvement and recovery in several physiological systems.
Collapse
Affiliation(s)
- Shipra Puri
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States of America; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States of America
| | - Gino Panza
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States of America; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States of America
| | - Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States of America; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States of America; Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201, United States of America.
| |
Collapse
|
9
|
Alex RM, Panza GS, Hakim H, Badr MS, Edwards BA, Sands SA, Mateika JH. Exposure to mild intermittent hypoxia increases loop gain and the arousal threshold in participants with obstructive sleep apnoea. J Physiol 2019; 597:3697-3711. [DOI: 10.1113/jp277711] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/04/2019] [Indexed: 01/03/2023] Open
Affiliation(s)
- Raichel M. Alex
- John D. Dingell Veterans Affairs Medical Center Detroit MI 48201 USA
- Department of PhysiologyWayne State University School of Medicine Detroit MI 48201 USA
| | - Gino S. Panza
- John D. Dingell Veterans Affairs Medical Center Detroit MI 48201 USA
- Department of PhysiologyWayne State University School of Medicine Detroit MI 48201 USA
| | - Huzaifa Hakim
- John D. Dingell Veterans Affairs Medical Center Detroit MI 48201 USA
- Department of PhysiologyWayne State University School of Medicine Detroit MI 48201 USA
| | - M. Safwan Badr
- John D. Dingell Veterans Affairs Medical Center Detroit MI 48201 USA
- Department of PhysiologyWayne State University School of Medicine Detroit MI 48201 USA
- Department of Internal MedicineWayne State University School of Medicine Detroit MI 48201 USA
| | - Bradley A. Edwards
- Sleep and Circadian Medicine LaboratoryDepartment of Physiology Monash University Melbourne Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical NeurosciencesMonash University Melbourne Australia
| | - Scott A. Sands
- Division of Sleep and Circadian DisordersBrigham and Women's Hospital and Harvard Medical School Boston MA USA
| | - Jason H. Mateika
- John D. Dingell Veterans Affairs Medical Center Detroit MI 48201 USA
- Department of PhysiologyWayne State University School of Medicine Detroit MI 48201 USA
- Department of Internal MedicineWayne State University School of Medicine Detroit MI 48201 USA
| |
Collapse
|
10
|
Panza GS, Alex RM, Yokhana SS, Lee Pioszak DS, Badr MS, Mateika JH. Increased Oxidative Stress, Loop Gain And The Arousal Threshold Are Clinical Predictors Of Increased Apnea Severity Following Exposure To Intermittent Hypoxia. Nat Sci Sleep 2019; 11:265-279. [PMID: 31695534 PMCID: PMC6817348 DOI: 10.2147/nss.s228100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/04/2019] [Indexed: 01/06/2023] Open
Abstract
PURPOSE We determined if oxidative stress prior to sleep onset is correlated to loop gain (LG) and the arousal threshold (AT) during non-rapid eye movement (NREM) sleep. We also explored if LG and AT are correlated with apnea severity and indices of upper airway collapsibility during NREM sleep. METHODS Thirteen male participants with obstructive sleep apnea (apnea-hypopnea index > 5 events/hr) were administered an antioxidant or placebo cocktail while exposed to mild intermittent hypoxia in the awake state. Thereafter, loop gain and measures of arousal, apnea severity and upper airway collapsibility were ascertained during NREM sleep. RESULTS Modification in oxidative stress (i.e., 8-hydroxy-2-deoxyguanosine) prior to sleep onset was correlated to LG (r = 0.8, P = 0.003), the number (r = 0.71, P = 0.01) and duration (r = 0.63, P = 0.04) of apneic events and the percentage of time breathing was stable (r = -0.66, P = 0.03) during sleep. Using a forward stepwise regression analysis, our results showed that LG, AT, the ventilatory response to arousal and nadir end-tidal carbon dioxide were determinants of the apnea-hypopnea index (P value range = 0.04-0.001). In addition, the AT was a predictor of measures of upper airway collapsibility, including the hypopnea/apnea + hypopnea ratio and the degree of flow reduction that accompanied hypopneic events (P < 0.001). CONCLUSION Modifications in oxidative stress following exposure to intermittent hypoxia during wakefulness are positively associated with loop gain and apnea severity during NREM sleep. Moreover, an increase in the arousal threshold is a predictor of increased upper airway collapsibility.
Collapse
Affiliation(s)
- Gino S Panza
- Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Raichel M Alex
- Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Sanar S Yokhana
- Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Dorothy S Lee Pioszak
- Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - M Safwan Badr
- Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.,Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Jason H Mateika
- Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.,Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201, USA
| |
Collapse
|
11
|
Podnar S, Dolenc Grošelj L. Neuropathic changes in the tongue protruder muscles in patients with snoring or obstructive sleep apnea. Neurophysiol Clin 2018; 48:269-275. [PMID: 29910146 DOI: 10.1016/j.neucli.2018.05.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/28/2018] [Accepted: 05/28/2018] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVE Both myopathic and neuropathic tongue protruder muscle changes have been demonstrated to occur in obstructive sleep apnea (OSA) patients using different methods. We tried to elucidate this dilemma using quantitative electromyographic (EMG) methods. METHODS In a group of consecutive patients with suspected OSA a full overnight polysomnography (PSG) and quantitative needle EMG of the tongue protruder, biceps brachii and vastus lateralis muscles were performed. EMG findings were compared to control subjects. RESULTS Of 23 patients, 8 were classified as simple snorers and the remaining 15 as OSA patients by PSG. Motor unit potential (MUP) parameters obtained in tongue protruder muscles, but not biceps brachii or vastus lateralis muscles, were significantly larger in patients compared to controls. However, no correlation was found between tongue protruder muscle MUP parameters and patient characteristics. DISCUSSION Our study confirmed previous findings of neuropathic changes in the tongue protruder muscles of OSA patients, and extended these to simple snorers. Changes were limited to the upper airway muscle, and could not been explained by the severity or duration of the sleep breathing disorder. The possible role of denervation injury caused by the upper airway vibrations should be tested in the future by appropriately designed studies.
Collapse
Affiliation(s)
- Simon Podnar
- Institute of Clinical Neurophysiology, Division of Neurology, University Medical Center Ljubljana, 1525 Ljubljana, Slovenia.
| | - Leja Dolenc Grošelj
- Institute of Clinical Neurophysiology, Division of Neurology, University Medical Center Ljubljana, 1525 Ljubljana, Slovenia
| |
Collapse
|
12
|
Mateika JH, Panza G, Alex R, El-Chami M. The impact of intermittent or sustained carbon dioxide on intermittent hypoxia initiated respiratory plasticity. What is the effect of these combined stimuli on apnea severity? Respir Physiol Neurobiol 2017; 256:58-66. [PMID: 29097171 DOI: 10.1016/j.resp.2017.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 10/13/2017] [Accepted: 10/21/2017] [Indexed: 11/28/2022]
Abstract
The following review explores the effect that intermittent or sustained hypercapnia coupled to intermittent hypoxia has on respiratory plasticity. The review explores published work which suggests that intermittent hypercapnia leads to long-term depression of respiration when administered in isolation and prevents the initiation of long-term facilitation when administered in combination with intermittent hypoxia. The review also explores the impact that sustained hypercapnia alone and in combination with intermittent hypoxia has on the magnitude of long-term facilitation. After exploring the outcomes linked to intermittent hypoxia/hypercapnia and intermittent hypoxia/sustained hypercapnia the translational relevance of the outcomes as it relates to breathing stability during sleep is addressed. The likelihood that naturally induced cycles of intermittent hypoxia, coupled to oscillations in carbon dioxide that range between hypocapnia and hypercapnia, do not initiate long-term facilitation is addressed. Moreover, the conditions under which intermittent hypoxia/sustained hypercapnia could serve to improve breathing stability and mitigate co-morbidities associated with sleep apnea are considered.
Collapse
Affiliation(s)
- Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI, 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, United States; Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI, 48201, United States.
| | - Gino Panza
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI, 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, United States
| | - Raichel Alex
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI, 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, United States
| | - Mohamad El-Chami
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI, 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, United States
| |
Collapse
|
13
|
El-Chami M, Sudan S, Lin HS, Mateika JH. Exposure to intermittent hypoxia and sustained hypercapnia reduces therapeutic CPAP in participants with obstructive sleep apnea. J Appl Physiol (1985) 2017; 123:993-1002. [DOI: 10.1152/japplphysiol.00204.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 06/30/2017] [Accepted: 07/01/2017] [Indexed: 12/31/2022] Open
Abstract
Our purpose was to determine whether exposure to mild intermittent hypoxia leads to a reduction in the therapeutic continuous positive airway pressure required to eliminate breathing events. Ten male participants were treated with twelve 2-min episodes of hypoxia ([Formula: see text] ≈50 mmHg) separated by 2-min intervals of normoxia in the presence of [Formula: see text] that was sustained 3 mmHg above baseline. During recovery from the last episode, the positive airway pressure was reduced in a stepwise fashion until flow limitation was evident. The participants also completed a sham protocol under normocapnic conditions, which mimicked the time frame of the intermittent hypoxia protocol. After exposure to intermittent hypoxia, the therapeutic pressure was significantly reduced (i.e., 5 cmH2O) without evidence of flow limitation (103.4 ± 6.3% of baseline, P = 0.5) or increases in upper airway resistance (95.6 ± 15.0% of baseline, P = 0.6). In contrast, a similar decrease in pressure was accompanied by flow limitation (77.0 ± 1.8% of baseline, P = 0.001) and an increase in upper airway resistance (167.2 ± 17.5% of baseline, P = 0.01) after the sham protocol. Consistent with the initiation of long-term facilitation of upper airway muscle activity, exposure to intermittent hypoxia reduced the therapeutic pressure required to eliminate apneic events that could improve treatment compliance. This possibility, coupled with the potentially beneficial effects of intermittent hypoxia on comorbidities linked to sleep apnea, suggests that mild intermittent hypoxia may have a multipronged therapeutic effect on sleep apnea. NEW & NOTEWORTHY Our new finding is that exposure to mild intermittent hypoxia reduced the therapeutic pressure required to treat sleep apnea. These findings are consistent with previous results, which have shown that long-term facilitation of upper muscle activity can be initiated following exposure to intermittent hypoxia in humans.
Collapse
Affiliation(s)
- Mohamad El-Chami
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Sukhesh Sudan
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Ho-Sheng Lin
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine and Karmanos Cancer Institute, Detroit, Michigan
| | - Jason H. Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
- Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan; and
| |
Collapse
|
14
|
Deacon NL, McEvoy RD, Stadler DL, Catcheside PG. Intermittent hypercapnic hypoxia during sleep does not induce ventilatory long-term facilitation in healthy males. J Appl Physiol (1985) 2017; 123:534-543. [DOI: 10.1152/japplphysiol.01005.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 11/22/2022] Open
Abstract
Intermittent hypoxia-induced ventilatory neuroplasticity is likely important in obstructive sleep apnea pathophysiology. Although concomitant CO2levels and arousal state critically influence neuroplastic effects of intermittent hypoxia, no studies have investigated intermittent hypercapnic hypoxia effects during sleep in humans. Thus the purpose of this study was to investigate if intermittent hypercapnic hypoxia during sleep induces neuroplasticity (ventilatory long-term facilitation and increased chemoreflex responsiveness) in humans. Twelve healthy males were exposed to intermittent hypercapnic hypoxia (24 × 30 s episodes of 3% CO2and 3.0 ± 0.2% O2) and intermittent medical air during sleep after 2 wk washout period in a randomized crossover study design. Minute ventilation, end-tidal CO2, O2saturation, breath timing, upper airway resistance, and genioglossal and diaphragm electromyograms were examined during 10 min of stable stage 2 sleep preceding gas exposure, during gas and intervening room air periods, and throughout 1 h of room air recovery. There were no significant differences between conditions across time to indicate long-term facilitation of ventilation, genioglossal or diaphragm electromyogram activity, and no change in ventilatory response from the first to last gas exposure to suggest any change in chemoreflex responsiveness. These findings contrast with previous intermittent hypoxia studies without intermittent hypercapnia and suggest that the more relevant gas disturbance stimulus of concomitant intermittent hypercapnia frequently occurring in sleep apnea influences acute neuroplastic effects of intermittent hypoxia. These findings highlight the need for further studies of intermittent hypercapnic hypoxia during sleep to clarify the role of ventilatory neuroplasticity in the pathophysiology of sleep apnea.NEW & NOTEWORTHY Both arousal state and concomitant CO2levels are known modulators of the effects of intermittent hypoxia on ventilatory neuroplasticity. This is the first study to investigate the effects of combined intermittent hypercapnic hypoxia during sleep in humans. The lack of neuroplastic effects suggests a need for further studies more closely replicating obstructive sleep apnea to determine the pathophysiological relevance of intermittent hypoxia-induced ventilatory neuroplasticity.
Collapse
Affiliation(s)
- Naomi L. Deacon
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
| | - R. Doug McEvoy
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
- School of Medicine, Flinders University, Bedford Park, South Australia, Australia
| | - Daniel L. Stadler
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
| | - Peter G. Catcheside
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
- School of Medicine, Flinders University, Bedford Park, South Australia, Australia
| |
Collapse
|
15
|
Lemes EV, Aiko S, Orbem CB, Formentin C, Bassi M, Colombari E, Zoccal DB. Long-term facilitation of expiratory and sympathetic activities following acute intermittent hypoxia in rats. Acta Physiol (Oxf) 2016; 217:254-66. [PMID: 26910756 DOI: 10.1111/apha.12661] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/14/2016] [Accepted: 02/15/2016] [Indexed: 12/20/2022]
Abstract
AIM Acute intermittent hypoxia (AIH) promotes persistent increases in ventilation and sympathetic activity, referred as long-term facilitation (LTF). Augmented inspiratory activity is suggested as a major component of respiratory LTF. In this study, we hypothesized that AIH also elicits a sustained increase in expiratory motor activity. We also investigated whether the expiratory LTF contributes to the development of sympathetic LTF after AIH. METHODS Rats were exposed to AIH (10 × 6-7% O2 for 45 s, every 5 min), and the cardiorespiratory parameters were evaluated during 60 min using in vivo and in situ approaches. RESULTS In unanesthetized conditions (n = 9), AIH elicited a modest but sustained increase in baseline mean arterial pressure (MAP, 104 ± 2 vs. 111 ± 3 mmHg, P < 0.05) associated with enhanced sympathetic and respiratory-related variabilities. In the in situ preparations (n = 9), AIH evoked LTF in phrenic (33 ± 12%), thoracic sympathetic (75 ± 25%) and abdominal nerve activities (69 ± 14%). The sympathetic overactivity after AIH was phase-locked with the emergence of bursts in abdominal activity during the late-expiratory phase. In anesthetized vagus-intact animals, AIH increased baseline MAP (113 ± 3 vs. 122 ± 2 mmHg, P < 0.05) and abdominal muscle activity (535 ± 94%), which were eliminated after pharmacological inhibition of the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG). CONCLUSION These findings indicate that increased expiratory activity is also an important component of AIH-elicited respiratory LTF. Moreover, the development of sympathetic LTF after AIH is linked to the emergence of active expiratory pattern and depends on the integrity of the neurones of the RTN/pFRG.
Collapse
Affiliation(s)
- E. V. Lemes
- Department of Physiology and Pathology; School of Dentistry of Araraquara; São Paulo State University (UNESP); Araraquara SP Brazil
| | - S. Aiko
- Department of Physiological Sciences; Centre of Biological Sciences; Federal University of Santa Catarina (UFSC); Florianópolis SC Brazil
| | - C. B. Orbem
- Department of Physiological Sciences; Centre of Biological Sciences; Federal University of Santa Catarina (UFSC); Florianópolis SC Brazil
| | - C. Formentin
- Department of Physiological Sciences; Centre of Biological Sciences; Federal University of Santa Catarina (UFSC); Florianópolis SC Brazil
| | - M. Bassi
- Department of Physiology and Pathology; School of Dentistry of Araraquara; São Paulo State University (UNESP); Araraquara SP Brazil
| | - E. Colombari
- Department of Physiology and Pathology; School of Dentistry of Araraquara; São Paulo State University (UNESP); Araraquara SP Brazil
| | - D. B. Zoccal
- Department of Physiology and Pathology; School of Dentistry of Araraquara; São Paulo State University (UNESP); Araraquara SP Brazil
| |
Collapse
|
16
|
Pamenter ME, Powell FL. Time Domains of the Hypoxic Ventilatory Response and Their Molecular Basis. Compr Physiol 2016; 6:1345-85. [PMID: 27347896 DOI: 10.1002/cphy.c150026] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ventilatory responses to hypoxia vary widely depending on the pattern and length of hypoxic exposure. Acute, prolonged, or intermittent hypoxic episodes can increase or decrease breathing for seconds to years, both during the hypoxic stimulus, and also after its removal. These myriad effects are the result of a complicated web of molecular interactions that underlie plasticity in the respiratory control reflex circuits and ultimately control the physiology of breathing in hypoxia. Since the time domains of the physiological hypoxic ventilatory response (HVR) were identified, considerable research effort has gone toward elucidating the underlying molecular mechanisms that mediate these varied responses. This research has begun to describe complicated and plastic interactions in the relay circuits between the peripheral chemoreceptors and the ventilatory control circuits within the central nervous system. Intriguingly, many of these molecular pathways seem to share key components between the different time domains, suggesting that varied physiological HVRs are the result of specific modifications to overlapping pathways. This review highlights what has been discovered regarding the cell and molecular level control of the time domains of the HVR, and highlights key areas where further research is required. Understanding the molecular control of ventilation in hypoxia has important implications for basic physiology and is emerging as an important component of several clinical fields. © 2016 American Physiological Society. Compr Physiol 6:1345-1385, 2016.
Collapse
Affiliation(s)
| | - Frank L Powell
- Physiology Division, Department of Medicine, University of California San Diego, La Jolla, California, USA
| |
Collapse
|
17
|
Mateika JH, Komnenov D. Intermittent hypoxia initiated plasticity in humans: A multipronged therapeutic approach to treat sleep apnea and overlapping co-morbidities. Exp Neurol 2016; 287:113-129. [PMID: 27170208 DOI: 10.1016/j.expneurol.2016.05.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/18/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
Abstract
Over the past three decades exposure to intermittent hypoxia (IH) has generally been considered a stimulus associated with a number of detrimental outcomes. However, there is sufficient evidence to link IH to many beneficial outcomes but they have largely been ignored, particularly in the field of sleep medicine in the United States. Recent reviews have postulated that this apparent contradiction is related to the severity and duration of exposure to IH; mild forms of IH initiate beneficial outcomes while severe forms of IH are coupled to detrimental consequences. In the present review we explore the role that IH has in initiating respiratory plasticity and the potential this form of plasticity has to mitigate obstructive sleep apnea (OSA) in humans. In taking this approach, we address the possibility that IH could serve as an adjunct therapy coupled with continuous positive airway pressure (CPAP) to treat OSA. Our working hypothesis is that exposure to mild IH leads to respiratory plasticity that manifests in increased stability of the upper airway, which could ultimately reduce the CPAP required to treat OSA. In turn, this reduction could increase CPAP compliance and extend the length of treatment each night, which might improve the magnitude of outcome measures. Improved treatment compliance coupled with the direct effect that IH has on numerous overlapping conditions (i.e. asthma, chronic obstructive pulmonary disease, spinal cord injury) may well lead to substantial improvements that exceed outcomes following treatment with CPAP alone. Overall, this review will consider evidence from the published literature which suggests that IH could serve as an effective multipronged therapeutic approach to treat sleep apnea and its overlapping co-morbidities.
Collapse
Affiliation(s)
- Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States; Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201, United States.
| | - Dragana Komnenov
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| |
Collapse
|
18
|
Alamin FAERM, Ayad CE. Characterization of Upper Air Way Tract in Snoring and Non-Snoring Patients: A CT Based Study. OPEN JOURNAL OF RADIOLOGY 2016; 06:181-190. [DOI: 10.4236/ojrad.2016.63025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
19
|
Dubey A, Upadhyay S, Mathur S, Kant S, Singh BP, Makwana R. Comparative evaluation of craniofacial anthropometric measurements in Indian adult patients with and without obstructive sleep apnea: A pilot study. J Indian Prosthodont Soc 2015; 15:331-6. [PMID: 26929536 PMCID: PMC4762347 DOI: 10.4103/0972-4052.161567] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 06/11/2015] [Indexed: 11/25/2022] Open
Abstract
AIMS The study aimed to compare the craniofacial features of North Indian patients suffering from obstructive sleep apnea (OSA) to that of normal North Indian population. MATERIALS AND METHODS Selected 25 North Indian subjects (age: 18-65 years) were divided into two groups (OSA group [n = 14] and non-OSA group [n = 9]) according to the results of full night polysomnographic sleep study. Body mass index (BMI), neck circumference (NC), and lateral cephalograms were recorded for each subject in both groups and total 22 parameters of craniofacial anthropometric features were measured on lateral cephalograms for each subject. The differences in BMI, NC, and craniofacial features between the OSA and non-OSA groups were compared statistically. RESULTS Independent sample t-test was used to compare the differences between OSA group and non-OSA group. The results showed that the BMI, NC, bulk of tongue (tongue length, tongue height, and tongue area) and length of the soft palate (PNS-U) were significantly higher in OSA group. OSA group was also found to have inferior positioning of hyoid bone (MP-H, ANS-H, PNS-H, ANS-Eb), narrower superior and middle airway space (SPAS and MAS), antero-inferior positioning of mandible (Gn-C3, ANS-Me, SNB, N-Me) and lower cranial base flexure angle (N-S-Ba). CONCLUSION Craniofacial features, which play an important role in the pathophysiology of OSA, differ significantly between North Indian patients suffering from OSA and normal North Indian population.
Collapse
Affiliation(s)
- Abhishek Dubey
- Department of Pulmonary Medicine, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Snehal Upadhyay
- Department of Prosthodontics and Oral Implantology, Faculty of Dental Sciences, Dharamsinh Desai University, Nadiad, Gujarat, India
| | - Somil Mathur
- Department of Prosthodontics and Oral Implantology, Faculty of Dental Sciences, Dharamsinh Desai University, Nadiad, Gujarat, India
| | - Surya Kant
- Department of Pulmonary Medicine, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Balendra Pratap Singh
- Department of Prosthodontics, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Rakesh Makwana
- Department of Prosthodontics and Oral Implantology, Faculty of Dental Sciences, Dharamsinh Desai University, Nadiad, Gujarat, India
| |
Collapse
|
20
|
Chowdhuri S, Pranathiageswaran S, Franco-Elizondo R, Jayakar A, Hosni A, Nair A, Badr MS. Effect of age on long-term facilitation and chemosensitivity during NREM sleep. J Appl Physiol (1985) 2015; 119:1088-96. [PMID: 26316510 DOI: 10.1152/japplphysiol.00030.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 08/04/2015] [Indexed: 12/31/2022] Open
Abstract
The reason for increased sleep-disordered breathing with a predominance of central apneas in the elderly is unknown. We speculate that ventilatory control instability may provide a link between aging and the onset of unstable breathing during sleep. We sought to investigate potential underlying mechanisms in healthy, elderly adults during sleep. We hypothesized that there is 1) a decline in respiratory plasticity or long-term facilitation (LTF) of ventilation and/or 2) increased ventilatory chemosensitivity in older adults during non-, this should be hyphenated, non-rapid rapid eye movement (NREM) sleep. Fourteen elderly adults underwent 15, 1-min episodes of isocapnic hypoxia (EH), nadir O2 saturation: 87.0 ± 0.8%. Measurements were obtained during control, hypoxia, and up to 20 min of recovery following the EH protocol, respectively, for minute ventilation (VI), timing, and inspiratory upper-airway resistances (RUA). The results showed the following. 1) Compared with baseline, there was a significant increase in VI (158 ± 11%, P < 0.05) during EH, but this was not accompanied by augmentation of VI during the successive hypoxia trials nor in VI during the recovery period (94.4 ± 3.5%, P = not significant), indicating an absence of LTF. There was no change in inspiratory RUA during the trials. This is in contrast to our previous findings of respiratory plasticity in young adults during sleep. Sham studies did not show a change in any of the measured parameters. 2) We observed increased chemosensitivity with increased isocapnic hypoxic ventilatory response and hyperoxic suppression of VI in older vs. young adults during NREM sleep. Thus increased chemosensitivity, unconstrained by respiratory plasticity, may explain increased periodic breathing and central apneas in elderly adults during NREM sleep.
Collapse
Affiliation(s)
- Susmita Chowdhuri
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Sukanya Pranathiageswaran
- Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Rene Franco-Elizondo
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Arunima Jayakar
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Arwa Hosni
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Ajin Nair
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and
| | - M Safwan Badr
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| |
Collapse
|
21
|
The role of high loop gain induced by intermittent hypoxia in the pathophysiology of obstructive sleep apnoea. Sleep Med Rev 2015; 22:3-14. [DOI: 10.1016/j.smrv.2014.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 10/03/2014] [Accepted: 10/07/2014] [Indexed: 02/06/2023]
|
22
|
The role of high loop gain induced by intermittent hypoxia in the pathophysiology of obstructive sleep apnea. Sleep Med Rev 2015; 22:1-2. [PMID: 25770004 DOI: 10.1016/j.smrv.2015.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/24/2022]
|
23
|
Verges S, Chacaroun S, Godin-Ribuot D, Baillieul S. Hypoxic Conditioning as a New Therapeutic Modality. Front Pediatr 2015; 3:58. [PMID: 26157787 PMCID: PMC4476260 DOI: 10.3389/fped.2015.00058] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/03/2015] [Indexed: 01/03/2023] Open
Abstract
Preconditioning refers to a procedure by which a single noxious stimulus below the threshold of damage is applied to the tissue in order to increase resistance to the same or even different noxious stimuli given above the threshold of damage. Hypoxic preconditioning relies on complex and active defenses that organisms have developed to counter the adverse consequences of oxygen deprivation. The protection it confers against ischemic attack for instance as well as the underlying biological mechanisms have been extensively investigated in animal models. Based on these data, hypoxic conditioning (consisting in recurrent exposure to hypoxia) has been suggested a potential non-pharmacological therapeutic intervention to enhance some physiological functions in individuals in whom acute or chronic pathological events are anticipated or existing. In addition to healthy subjects, some benefits have been reported in patients with cardiovascular and pulmonary diseases as well as in overweight and obese individuals. Hypoxic conditioning consisting in sessions of intermittent exposure to moderate hypoxia repeated over several weeks may induce hematological, vascular, metabolic, and neurological effects. This review addresses the existing evidence regarding the use of hypoxic conditioning as a potential therapeutic modality, and emphasizes on many remaining issues to clarify and future researches to be performed in the field.
Collapse
Affiliation(s)
- Samuel Verges
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| | - Samarmar Chacaroun
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| | - Diane Godin-Ribuot
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| | - Sébastien Baillieul
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| |
Collapse
|
24
|
Mateika JH, El-Chami M, Shaheen D, Ivers B. Intermittent hypoxia: a low-risk research tool with therapeutic value in humans. J Appl Physiol (1985) 2014; 118:520-32. [PMID: 25549763 DOI: 10.1152/japplphysiol.00564.2014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Intermittent hypoxia has generally been perceived as a high-risk stimulus, particularly in the field of sleep medicine, because it is thought to initiate detrimental cardiovascular, respiratory, cognitive, and metabolic outcomes. In contrast, the link between intermittent hypoxia and beneficial outcomes has received less attention, perhaps because it is not universally understood that outcome measures following exposure to intermittent hypoxia may be linked to the administered dose. The present review is designed to emphasize the less recognized beneficial outcomes associated with intermittent hypoxia. The review will consider the role intermittent hypoxia has in cardiovascular and autonomic adaptations, respiratory motor plasticity, and cognitive function. Each section will highlight the literature that contributed to the belief that intermittent hypoxia leads primarily to detrimental outcomes. The second segment of each section will consider the possible risks associated with experimentally rather than naturally induced intermittent hypoxia. Finally, the body of literature indicating that intermittent hypoxia initiates primarily beneficial outcomes will be considered. The overarching theme of the review is that the use of intermittent hypoxia in research investigations, coupled with reasonable safeguards, should be encouraged because of the potential benefits linked to the administration of a variety of low-risk intermittent hypoxia protocols.
Collapse
Affiliation(s)
- Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Mohamad El-Chami
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - David Shaheen
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Blake Ivers
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| |
Collapse
|
25
|
Navarrete-Opazo A, Mitchell GS. Therapeutic potential of intermittent hypoxia: a matter of dose. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1181-97. [PMID: 25231353 DOI: 10.1152/ajpregu.00208.2014] [Citation(s) in RCA: 289] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Intermittent hypoxia (IH) has been the subject of considerable research in recent years, and triggers a bewildering array of both detrimental and beneficial effects in multiple physiological systems. Here, we review the extensive literature concerning IH and its impact on the respiratory, cardiovascular, immune, metabolic, bone, and nervous systems. One major goal is to define relevant IH characteristics leading to safe, protective, and/or therapeutic effects vs. pathogenesis. To understand the impact of IH, it is essential to define critical characteristics of the IH protocol under investigation, including potentially the severity of hypoxia within episodes, the duration of hypoxic episodes, the number of hypoxic episodes per day, the pattern of presentation across time (e.g., within vs. consecutive vs. alternating days), and the cumulative time of exposure. Not surprisingly, severe/chronic IH protocols tend to be pathogenic, whereas any beneficial effects are more likely to arise from modest/acute IH exposures. Features of the IH protocol most highly associated with beneficial vs. pathogenic outcomes include the level of hypoxemia within episodes and the number of episodes per day. Modest hypoxia (9-16% inspired O2) and low cycle numbers (3-15 episodes per day) most often lead to beneficial effects without pathology, whereas severe hypoxia (2-8% inspired O2) and more episodes per day (48-2,400 episodes/day) elicit progressively greater pathology. Accumulating evidence suggests that "low dose" IH (modest hypoxia, few episodes) may be a simple, safe, and effective treatment with considerable therapeutic potential for multiple clinical disorders.
Collapse
Affiliation(s)
- Angela Navarrete-Opazo
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| |
Collapse
|
26
|
Saboisky JP, Stashuk DW, Hamilton-Wright A, Trinder J, Nandedkar S, Malhotra A. Effects of aging on genioglossus motor units in humans. PLoS One 2014; 9:e104572. [PMID: 25111799 PMCID: PMC4128697 DOI: 10.1371/journal.pone.0104572] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/10/2014] [Indexed: 11/21/2022] Open
Abstract
The genioglossus is a major upper airway dilator muscle thought to be important in obstructive sleep apnea pathogenesis. Aging is a risk factor for obstructive sleep apnea although the mechanisms are unclear and the effects of aging on motor unit remodeled in the genioglossus remains unknown. To assess possible changes associated with aging we compared quantitative parameters related to motor unit potential morphology derived from EMG signals in a sample of older (n = 11; >55 years) versus younger (n = 29; <55 years) adults. All data were recorded during quiet breathing with the subjects awake. Diagnostic sleep studies (Apnea Hypopnea Index) confirmed the presence or absence of obstructive sleep apnea. Genioglossus EMG signals were analyzed offline by automated software (DQEMG), which estimated a MUP template from each extracted motor unit potential train (MUPT) for both the selective concentric needle and concentric needle macro (CNMACRO) recorded EMG signals. 2074 MUPTs from 40 subjects (mean±95% CI; older AHI 19.6±9.9 events/hr versus younger AHI 30.1±6.1 events/hr) were extracted. MUPs detected in older adults were 32% longer in duration (14.7±0.5 ms versus 11.1±0.2 ms; P = 0.05), with similar amplitudes (395.2±25.1 µV versus 394.6±13.7 µV). Amplitudes of CNMACRO MUPs detected in older adults were larger by 22% (62.7±6.5 µV versus 51.3±3.0 µV; P<0.05), with areas 24% larger (160.6±18.6 µV.ms versus 130.0±7.4 µV.ms; P<0.05) than those detected in younger adults. These results confirm that remodeled motor units are present in the genioglossus muscle of individuals above 55 years, which may have implications for OSA pathogenesis and aging related upper airway collapsibility.
Collapse
Affiliation(s)
- Julian P. Saboisky
- Division of Sleep Medicine, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Prince of Wales Clinical School, Faculty of Medicine University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
| | - Daniel W. Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada
| | - Andrew Hamilton-Wright
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - John Trinder
- School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Atul Malhotra
- Division of Sleep Medicine, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
- University of California San Diego, La Jolla, California, United States of America
| |
Collapse
|
27
|
Abstract
Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive collapse of the pharyngeal airway during sleep. Control of pharyngeal patency is a complex process relating primarily to basic anatomy and the activity of many pharyngeal dilator muscles. The control of these muscles is regulated by a number of processes including respiratory drive, negative pressure reflexes, and state (sleep) effects. In general, patients with OSA have an anatomically small airway the patency of which is maintained during wakefulness by reflex-driven augmented dilator muscle activation. At sleep onset, muscle activity falls, thereby compromising the upper airway. However, recent data suggest that the mechanism of OSA differs substantially among patients, with variable contributions from several physiologic characteristics including, among others: level of upper airway dilator muscle activation required to open the airway, increase in chemical drive required to recruit the pharyngeal muscles, chemical control loop gain, and arousal threshold. Thus, the cause of sleep apnea likely varies substantially between patients. Other physiologic mechanisms likely contributing to OSA pathogenesis include falling lung volume during sleep, shifts in blood volume from peripheral tissues to the neck, and airway edema. Apnea severity may progress over time, likely due to weight gain, muscle/nerve injury, aging effects on airway anatomy/collapsibility, and changes in ventilatory control stability.
Collapse
Affiliation(s)
- David P White
- Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA.
| | | |
Collapse
|
28
|
Xing T, Fong AY, Bautista TG, Pilowsky PM. Acute intermittent hypoxia induced neural plasticity in respiratory motor control. Clin Exp Pharmacol Physiol 2013; 40:602-9. [DOI: 10.1111/1440-1681.12129] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/24/2013] [Accepted: 05/26/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Tao Xing
- Australian School of Advanced Medicine; Macquarie University; Sydney NSW Australia
| | - Angelina Y Fong
- Australian School of Advanced Medicine; Macquarie University; Sydney NSW Australia
| | - Tara G Bautista
- Australian School of Advanced Medicine; Macquarie University; Sydney NSW Australia
| | - Paul M Pilowsky
- Australian School of Advanced Medicine; Macquarie University; Sydney NSW Australia
| |
Collapse
|
29
|
Syed Z, Lin HS, Mateika JH. The impact of arousal state, sex, and sleep apnea on the magnitude of progressive augmentation and ventilatory long-term facilitation. J Appl Physiol (1985) 2012; 114:52-65. [PMID: 23139361 DOI: 10.1152/japplphysiol.00985.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the impact of arousal state, sex, and obstructive sleep apnea (OSA) on the magnitude of progressive augmentation of the hypoxic ventilatory response and ventilatory long-term facilitation (vLTF). We also examined whether exposure to intermittent hypoxia during sleep has an impact on the apnea-hypopnea index (AHI) in individuals with OSA. Ten men and seven women with OSA, along with ten healthy men and ten healthy women, were exposed to twelve 2-min episodes of hypoxia (end-tidal PO(2): 50 Torr) in the presence of sustained hypercapnia (end-tidal PCO(2): 3 Torr above baseline), followed by a 30-min recovery period during wakefulness and sleep. The OSA participants completed an additional sham study during sleep. The AHI during the first hour of sleep following the intermittent hypoxia and sham protocols were compared. Progressive augmentation was only evident during wakefulness and was enhanced in the OSA participants. vLTF was evident during wakefulness and sleep. When standardized to baseline, vLTF was greater during wakefulness and was enhanced in the OSA group (men: wakefulness 1.39 ± 0.08 vs. sleep 1.14 ± 0.03; women: wakefulness 1.35 ± 0.03 vs. sleep 1.16 ± 0.05 fraction of baseline; P ≤ 0.001) compared with control (men: wakefulness 1.19 ± 0.03 vs. sleep 1.09 ± 0.03; women: wakefulness 1.26 ± 0.05 vs. sleep 1.08 ± 0.04 fraction of baseline; P ≤ 0.001). The AHI following exposure to intermittent hypoxia was increased (intermittent hypoxia 72.8 ± 7.3 vs. sham 56.5 ± 7.0 events/h; P ≤ 0.01). Sex-related differences were not observed for the primary measures. We conclude that progressive augmentation is not evident, and the magnitude of vLTF is diminished during sleep compared with wakefulness in men and women. However, when present, the phenomena are enhanced in individuals with OSA. The AHI data indicate that, under the prevailing experimental conditions, vLTF did not serve to mitigate apnea severity.
Collapse
Affiliation(s)
- Ziauddin Syed
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan 48201, USA
| | | | | |
Collapse
|
30
|
Bautista TG, Xing T, Fong AY, Pilowsky PM. Recurrent laryngeal nerve activity exhibits a 5-HT-mediated long-term facilitation and enhanced response to hypoxia following acute intermittent hypoxia in rat. J Appl Physiol (1985) 2012; 112:1144-56. [DOI: 10.1152/japplphysiol.01356.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A progressive and sustained increase in inspiratory-related motor output (“long-term facilitation”) and an augmented ventilatory response to hypoxia occur following acute intermittent hypoxia (AIH). To date, acute plasticity in respiratory motor outputs active in the postinspiratory and expiratory phases has not been studied. The recurrent laryngeal nerve (RLN) innervates laryngeal abductor muscles that widen the glottic aperture during inspiration. Other efferent fibers in the RLN innervate adductor muscles that partially narrow the glottic aperture during postinspiration. The aim of this study was to investigate whether or not AIH elicits a serotonin-mediated long-term facilitation of laryngeal abductor muscles, and if recruitment of adductor muscle activity occurs following AIH. Urethane anesthetized, paralyzed, unilaterally vagotomized, and artificially ventilated adult male Sprague-Dawley rats were subjected to 10 exposures of hypoxia (10% O2 in N2, 45 s, separated by 5 min, n = 7). At 60 min post-AIH, phrenic nerve activity and inspiratory RLN activity were elevated (39 ± 11 and 23 ± 6% above baseline, respectively). These responses were abolished by pretreatment with the serotonin-receptor antagonist, methysergide ( n = 4). No increase occurred in time control animals ( n = 7). Animals that did not exhibit postinspiratory RLN activity at baseline did not show recruitment of this activity post-AIH ( n = 6). A repeat hypoxia 60 min after AIH produced a significantly greater peak response in both phrenic and RLN activity, accompanied by a prolonged recovery time that was also prevented by pretreatment with methysergide. We conclude that AIH induces neural plasticity in laryngeal motoneurons, via serotonin-mediated mechanisms similar to that observed in phrenic motoneurons: the so-called “Q-pathway”. We also provide evidence that the augmented responsiveness to repeat hypoxia following AIH also involves a serotonergic mechanism.
Collapse
Affiliation(s)
- Tara G. Bautista
- Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| | - Tao Xing
- Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| | - Angelina Y. Fong
- Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| | - Paul M. Pilowsky
- Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| |
Collapse
|
31
|
Yokhana SS, Gerst DG, Lee DS, Badr MS, Qureshi T, Mateika JH. Impact of repeated daily exposure to intermittent hypoxia and mild sustained hypercapnia on apnea severity. J Appl Physiol (1985) 2011; 112:367-77. [PMID: 22052874 DOI: 10.1152/japplphysiol.00702.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined whether exposure to intermittent hypoxia (IH) during wakefulness impacted on the apnea/hypopnea index (AHI) during sleep in individuals with sleep apnea. Participants were exposed to twelve 4-min episodes of hypoxia in the presence of sustained mild hypercapnia each day for 10 days. A control group was exposed to sustained mild hypercapnia for a similar duration. The intermittent hypoxia protocol was completed in the evening on day 1 and 10 and was followed by a sleep study. During all sleep studies, the change in esophageal pressure (ΔPes) from the beginning to the end of an apnea and the tidal volume immediately following apneic events were used to measure respiratory drive. Following exposure to IH on day 1 and 10, the AHI increased above baseline measures (day 1: 1.95 ± 0.42 fraction of baseline, P ≤ 0.01, vs. day 10: 1.53 ± 0.24 fraction of baseline, P < 0.06). The indexes were correlated to the hypoxic ventilatory response (HVR) measured during the IH protocol but were not correlated to the magnitude of ventilatory long-term facilitation (vLTF). Likewise, ΔPes and tidal volume measures were greater on day 1 and 10 compared with baseline (ΔPes: -8.37 ± 0.84 vs. -5.90 ± 1.30 cmH(2)0, P ≤ 0.04; tidal volume: 1,193.36 ± 101.85 vs. 1,015.14 ± 119.83 ml, P ≤ 0.01). This was not the case in the control group. Interestingly, the AHI on day 10 (0.78 ± 0.13 fraction of baseline, P ≤ 0.01) was significantly less than measures obtained during baseline and day 1 in the mild hypercapnia control group. We conclude that enhancement of the HVR initiated by exposure to IH may lead to increases in the AHI during sleep and that initiation of vLTF did not appear to impact on breathing stability. Lastly, our results suggest that repeated daily exposure to mild sustained hypercapnia may lead to a decrease in breathing events.
Collapse
Affiliation(s)
- Sanar S Yokhana
- Department of Physiology, Wayne State University School of Medicine, Wayne State University, Detroit, Michigan, USA
| | | | | | | | | | | |
Collapse
|
32
|
Baker-Herman TL, Strey KA. Similarities and differences in mechanisms of phrenic and hypoglossal motor facilitation. Respir Physiol Neurobiol 2011; 179:48-56. [PMID: 21745601 DOI: 10.1016/j.resp.2011.06.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/27/2011] [Accepted: 06/27/2011] [Indexed: 12/17/2022]
Abstract
Intermittent hypoxia-induced long-term facilitation (LTF) is variably expressed in the motor output of several inspiratory nerves, such as the phrenic and hypoglossal. Compared to phrenic LTF (pLTF), less is known about hypoglossal LTF (hLTF), although it is often assumed that cellular mechanisms are the same. While fundamental mechanisms appear to be similar, potentially important differences exist in the modulation of pLTF and hLTF. The primary objectives of this paper are to: (1) review similarities and differences in pLTF and hLTF, pointing out knowledge gaps and (2) present new data suggesting that reduced respiratory neural activity elicits differential plasticity in phrenic and hypoglossal output (inactivity-induced phrenic and hypoglossal motor facilitation, iPMF and iHMF), suggesting that these motor pool-specific differences are not unique to LTF. Differences in fundamental mechanisms or modulation of plasticity among motor pools may confer the capacity to mount a complex ventilatory response to specific challenges, particularly in motor pools with different "jobs" in the control of breathing.
Collapse
Affiliation(s)
- Tracy L Baker-Herman
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706, USA.
| | | |
Collapse
|
33
|
Mateika JH, Sandhu KS. Experimental protocols and preparations to study respiratory long term facilitation. Respir Physiol Neurobiol 2011; 176:1-11. [PMID: 21292044 DOI: 10.1016/j.resp.2011.01.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 01/18/2011] [Accepted: 01/18/2011] [Indexed: 11/29/2022]
Abstract
Respiratory long-term facilitation is a form of neuronal plasticity that is induced following exposure to intermittent hypoxia. Long-term facilitation is characterized by a progressive increase in respiratory motor output during normoxic periods that separate hypoxic episodes and by a sustained elevation in respiratory activity for up to 90min after exposure to intermittent hypoxia. This phenomenon is associated with increases in phrenic, hypoglossal or carotid sinus nerve inspiratory-modulated discharge. The examination of long-term facilitation has been steadily ongoing for approximately 3 decades. During this period of time a variety of animal models (e.g. cats, rats and humans), experimental preparations and intermittent hypoxia protocols have been used to study long-term facilitation. This review is designed to summarize the strengths and weaknesses of the models, preparations and protocols that have been used to study LTF over the past 30 years. The review is divided into two primary sections. Initially, the models and protocols used to study LTF in animals other than humans will be discussed, followed by a section specifically focused on human studies. Each section will begin with a discussion of various factors that must be considered when selecting an experimental preparation and intermittent hypoxia protocol to examine LTF. Model and protocol design recommendations will follow, with the goal of presenting a prevailing model and protocol that will ultimately ensure standardized comparisons across studies.
Collapse
Affiliation(s)
- Jason H Mateika
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States.
| | | |
Collapse
|
34
|
Chowdhuri S, Sinha P, Pranathiageswaran S, Badr MS. Sustained hyperoxia stabilizes breathing in healthy individuals during NREM sleep. J Appl Physiol (1985) 2010; 109:1378-83. [PMID: 20724559 PMCID: PMC2980383 DOI: 10.1152/japplphysiol.00453.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 08/18/2010] [Indexed: 11/22/2022] Open
Abstract
The present study was designed to determine whether hyperoxia would lower the hypocapnic apneic threshold (AT) during non-rapid eye movement (NREM) sleep. Nasal noninvasive mechanical ventilation was used to induce hypocapnia and subsequent central apnea in healthy subjects during stable NREM sleep. Mechanical ventilation trials were conducted under normoxic (room air) and hyperoxic conditions (inspired PO(2) > 250 Torr) in a random order. The CO(2) reserve was defined as the minimal change in end-tidal PCO(2) (PET(CO(2))) between eupnea and hypocapnic central apnea. The PET(CO(2)) of the apnea closest to eupnea was designated as the AT. The hypocapnic ventilatory response was calculated as the change in ventilation below eupnea for a given change in PET(CO(2)). In nine participants, compared with room air, exposure to hyperoxia was associated with a significant decrease in eupneic PET(CO(2)) (37.5 ± 0.6 vs. 41.1 ± 0.6 Torr, P = 0.001), widening of the CO(2) reserve (-3.8 ± 0.8 vs. -2.0 ± 0.3 Torr, P = 0.03), and a subsequent decline in AT (33.3 ± 1.2 vs. 39.0 ± 0.7 Torr; P = 001). The hypocapnic ventilatory response was also decreased with hyperoxia. In conclusion, 1) hyperoxia was associated with a decreased AT and an increase in the magnitude of hypocapnia required for the development of central apnea. 2) Thus hyperoxia may mitigate the effects of hypocapnia on ventilatory motor output by lowering the hypocapnic ventilatory response and lowering the resting eupneic PET(CO(2)), thereby decreasing plant gain.
Collapse
Affiliation(s)
- Susmita Chowdhuri
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.
| | | | | | | |
Collapse
|
35
|
Chamberlin NL, Ling L. The effect of intermittent hypoxia on obstructive sleep apnea: beneficial or detrimental? J Appl Physiol (1985) 2010; 110:9-10. [PMID: 20966197 DOI: 10.1152/japplphysiol.01191.2010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
36
|
Julien CA, Niane L, Kinkead R, Bairam A, Joseph V. Carotid sinus nerve stimulation, but not intermittent hypoxia, induces respiratory LTF in adult rats exposed to neonatal intermittent hypoxia. Am J Physiol Regul Integr Comp Physiol 2010; 299:R192-205. [DOI: 10.1152/ajpregu.00707.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that exposure to neonatal intermittent hypoxia (n-IH) in rat pups alters central integrative processes following acute and intermittent peripheral chemoreceptor activation in adults. Newborn male rats were exposed to n-IH or normoxia for 10 consecutive days after birth. We then used both awake and anesthetized 3- to 4-mo-old rats to record ventilation, blood pressure, and phrenic and splanchnic nerve activities to assess responses to peripheral chemoreflex activation (acute hypoxic response) and long-term facilitation (LTF, long-term response after intermittent hypoxia). In anesthetized rats, phrenic and splanchnic nerve activities and hypoxic responses were also recorded with or without intact carotid body afferent signal (bilateral chemodenervation) or in response to electrical stimulations of the carotid sinus nerve. In awake rats, n-IH alters the respiratory pattern (higher frequency and lower tidal volume) and increased arterial blood pressure in normoxia, but the ventilatory response to repeated hypoxic cycles was not altered. In anesthetized rats, phrenic nerve responses to repeated hypoxic cycles or carotid sinus nerve stimulation were not altered by n-IH; however, the splanchnic nerve response was suppressed by n-IH compared with control. In control rats, respiratory LTF was apparent in anesthetized but not in awake animals. In n-IH rats, respiratory LTF was not apparent in awake and anesthetized animals. Following intermittent electrical stimulation, however, phrenic LTF was clearly present in n-IH rats, being similar in magnitude to controls. We conclude that, in adult n-IH rats: 1) arterial blood pressure is elevated, 2) peripheral chemoreceptor responses to hypoxia and its central integration are not altered, but splanchnic nerve response is suppressed, 3) LTF is suppressed, and 4) the mechanisms involved in the generation of LTF are still present but are masked most probably as the result of an augmented inhibitory response to hypoxia in the central nervous system.
Collapse
Affiliation(s)
- Cécile A. Julien
- Department of Pediatrics, Laval University, Centre de Recherche St.-François d'Assise, Québec, Canada
| | - Lalah Niane
- Department of Pediatrics, Laval University, Centre de Recherche St.-François d'Assise, Québec, Canada
| | - Richard Kinkead
- Department of Pediatrics, Laval University, Centre de Recherche St.-François d'Assise, Québec, Canada
| | - Aida Bairam
- Department of Pediatrics, Laval University, Centre de Recherche St.-François d'Assise, Québec, Canada
| | - Vincent Joseph
- Department of Pediatrics, Laval University, Centre de Recherche St.-François d'Assise, Québec, Canada
| |
Collapse
|
37
|
Cao Y, Ling L. Urethane inhibits genioglossal long-term facilitation in un-paralyzed anesthetized rats. Neurosci Lett 2010; 477:124-8. [PMID: 20433898 DOI: 10.1016/j.neulet.2010.04.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 04/17/2010] [Accepted: 04/20/2010] [Indexed: 11/15/2022]
Abstract
For approximately 3 decades, urethane has been (partially or solely) used as a successful anesthetic in numerous respiratory long-term facilitation (LTF) studies, which were performed on anesthetized, paralyzed, vagotomized and artificially ventilated animals of several different species. However, things become complicated when LTF of muscle activity is studied in un-paralyzed animals. For example, a commonly used acute intermittent hypoxia (AIH) protocol failed to induce muscle LTF in anesthetized, spontaneously breathing rats. But muscle LTF could be induced when hypoxic episode number was increased and/or anesthetics other than urethane were used. In these studies however, neither anesthetic nor paralysis was mentioned as a potential factor influencing AIH-induced muscle LTF. This study tested whether urethane inhibits AIH-induced genioglossal LTF (gLTF) in un-paralyzed ventilated rats, and if so, determined whether reducing urethane dose reverses this inhibition. Three groups of adult male Sprague-Dawley rats were anesthetized (Group 1: approximately 1.6 g kg(-1) urethane; Group 2: 50 mg kg(-1) alpha-chloralose +0.9-1.2 g kg(-1) urethane; Group 3: 0.9 g kg(-1) urethane +200-400 microg kg(-1) min(-1) alphaxalone), vagotomized and mechanically ventilated. Integrated genioglossus activity was measured before, during and after AIH (5 episodes of 3-min isocapnic 12% O(2), separated by 3-min hyperoxic intervals). The AIH-induced gLTF was absent in Group 1 rats (success rate was only approximately 1/7), but was present in Group 2 (in 10/12 rats) and Group 3 (in 11/11 rats) rats. The genioglossal response to hypoxia was not significantly different among the 3 groups. Collectively, these data suggest that urethane dose-dependently inhibits gLTF in un-paralyzed anesthetized rats.
Collapse
Affiliation(s)
- Ying Cao
- Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | |
Collapse
|
38
|
Cao Y, Liu C, Ling L. Glossopharyngeal long-term facilitation requires serotonin 5-HT2 and NMDA receptors in rats. Respir Physiol Neurobiol 2010; 170:164-72. [PMID: 20026287 PMCID: PMC2819572 DOI: 10.1016/j.resp.2009.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 12/11/2009] [Accepted: 12/14/2009] [Indexed: 10/20/2022]
Abstract
Although the glossopharyngeal nerve (IX) is mainly a sensory nerve, it innervates stylopharyngeus and some other pharyngeal muscles, whose excitations would likely improve upper airway patency since electrical IX stimulation increases pharyngeal airway size. As acute intermittent hypoxia (AIH) induces hypoglossal and genioglossal long-term facilitation (LTF), we hypothesized that AIH induces glossopharyngeal LTF, which requires serotonin 5-HT(2) and NMDA receptors. Integrated IX activity was recorded in anesthetized, vagotomized, paralyzed and ventilated rats before, during and after 5 episodes of 3-min isocapnic 12% O(2) with 3-min intervals of 50% O(2). Either saline, ketanserin (5-HT(2) antagonist, 2mg/kg) or MK-801 (NMDA antagonist, 0.2mg/kg) was (i.v.) injected 30-60 min before AIH. Both phasic and tonic IX activities were persistently increased (both P<0.05) after AIH in vehicle, but not ketanserin or MK-801, rats. Hypoxic glossopharyngeal responses were minimally changed after either drug. These data suggest that AIH induces both phasic and tonic glossopharyngeal LTF, which requires activation of 5-HT(2) and NMDA receptors.
Collapse
Affiliation(s)
- Ying Cao
- Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, BLI-043B, Boston, MA 02115, USA
| | | | | |
Collapse
|
39
|
Chowdhuri S, Shanidze I, Pierchala L, Belen D, Mateika JH, Badr MS. Effect of episodic hypoxia on the susceptibility to hypocapnic central apnea during NREM sleep. J Appl Physiol (1985) 2010; 108:369-77. [PMID: 19940101 PMCID: PMC2822673 DOI: 10.1152/japplphysiol.00308.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 11/25/2009] [Indexed: 11/22/2022] Open
Abstract
We hypothesized that episodic hypoxia (EH) leads to alterations in chemoreflex characteristics that might promote the development of central apnea in sleeping humans. We used nasal noninvasive positive pressure mechanical ventilation to induce hypocapnic central apnea in 11 healthy participants during stable nonrapid eye movement sleep before and after an exposure to EH, which consisted of fifteen 1-min episodes of isocapnic hypoxia (mean O(2) saturation/episode: 87.0 +/- 0.5%). The apneic threshold (AT) was defined as the absolute measured end-tidal PCO(2) (Pet(CO(2))) demarcating the central apnea. The difference between the AT and baseline Pet(CO(2)) measured immediately before the onset of mechanical ventilation was defined as the CO(2) reserve. The change in minute ventilation (V(I)) for a change in Pet(CO(2)) (DeltaV(I)/ DeltaPet(CO(2))) was defined as the hypocapnic ventilatory response. We studied the eupneic Pet(CO(2)), AT Pet(CO(2)), CO(2) reserve, and hypocapnic ventilatory response before and after the exposure to EH. We also measured the hypoxic ventilatory response, defined as the change in V(I) for a corresponding change in arterial O(2) saturation (DeltaV(I)/DeltaSa(O(2))) during the EH trials. V(I) increased from 6.2 +/- 0.4 l/min during the pre-EH control to 7.9 +/- 0.5 l/min during EH and remained elevated at 6.7 +/- 0.4 l/min the during post-EH recovery period (P < 0.05), indicative of long-term facilitation. The AT was unchanged after EH, but the CO(2) reserve declined significantly from -3.1 +/- 0.5 mmHg pre-EH to -2.3 +/- 0.4 mmHg post-EH (P < 0.001). In the post-EH recovery period, DeltaV(I)/DeltaPet(CO(2)) was higher compared with the baseline (3.3 +/- 0.6 vs. 1.8 +/- 0.3 l x min(-1) x mmHg(-1), P < 0.001), indicative of an increased hypocapnic ventilatory response. However, there was no significant change in the hypoxic ventilatory response (DeltaV(I)/DeltaSa(O(2))) during the EH period itself. In conclusion, despite the presence of ventilatory long-term facilitation, the increase in the hypocapnic ventilatory response after the exposure to EH induced a significant decrease in the CO(2) reserve. This form of respiratory plasticity may destabilize breathing and promote central apneas.
Collapse
Affiliation(s)
- Susmita Chowdhuri
- Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, USA.
| | | | | | | | | | | |
Collapse
|
40
|
Ling L. Serotonin and NMDA receptors in respiratory long-term facilitation. Respir Physiol Neurobiol 2009; 164:233-41. [PMID: 18606575 DOI: 10.1016/j.resp.2008.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 05/15/2008] [Accepted: 05/19/2008] [Indexed: 11/16/2022]
Abstract
Some have postulated that long-term facilitation (LTF), a persistent augmentation of respiratory activity after episodic hypoxia, may play a beneficial role in helping stabilize upper airway patency in obstructive sleep apnea (OSA) patients. However, the neuronal and cellular mechanisms underlying this plasticity of respiratory motor behavior are still poorly understood. The main purpose of this review is to summarize recent findings about serotonin and NMDA receptors involved in both LTF and its enhancement after chronic intermittent hypoxia (CIH). The potential roles of these receptors in the initiation, formation and/or maintenance of LTF, as well as the CIH effect on LTF, will be discussed. As background, different paradigms for the stimulus protocol, different patterns of LTF expression and their mechanistic implications in LTF will also be discussed.
Collapse
Affiliation(s)
- Liming Ling
- Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA.
| |
Collapse
|
41
|
Mateika JH, Narwani G. Intermittent hypoxia and respiratory plasticity in humans and other animals: does exposure to intermittent hypoxia promote or mitigate sleep apnoea? Exp Physiol 2009; 94:279-96. [PMID: 19060117 PMCID: PMC2771401 DOI: 10.1113/expphysiol.2008.045153] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This review focuses on two phenomena that are initiated during and after exposure to intermittent hypoxia. The two phenomena are referred to as long-term facilitation and progressive augmentation of respiratory motor output. Both phenomena are forms of respiratory plasticity. Long-term facilitation is characterized by a sustained elevation in respiratory activity after exposure to intermittent hypoxia. Progressive augmentation is characterized by a gradual increase in respiratory activity from the initial to the final hypoxic exposure. There is much speculation that long-term facilitation may have a significant role in individuals with sleep apnoea because this disorder is characterized by periods of upper airway collapse accompanied by intermittent hypoxia, one stimulus known to induce long-term facilitation. It has been suggested that activation of long-term facilitation may serve to mitigate apnoea by facilitating ventilation and, more importantly, upper airway muscle activity. We examine the less discussed but equally plausible situation that exposure to intermittent hypoxia might ultimately lead to the promotion of apnoea. There are at least two scenarios in which apnoea might be promoted following exposure to intermittent hypoxia. In both scenarios, long-term facilitation of upper airway muscle activity is initiated but ultimately rendered ineffective because of other physiological conditions. Thus, one of the primary goals of this review is to discuss, with support from basic and clinical studies, whether various forms of respiratory motor neuronal plasticity have a beneficial and/or a detrimental impact on breathing stability in individuals with sleep apnoea.
Collapse
Affiliation(s)
- Jason H Mateika
- John D. Dingell VA Medical Center, 4646 John R (11R), Room 4332, Detroit, MI 48201, USA.
| | | |
Collapse
|
42
|
Wilkerson JER, Mitchell GS. Daily intermittent hypoxia augments spinal BDNF levels, ERK phosphorylation and respiratory long-term facilitation. Exp Neurol 2009; 217:116-23. [PMID: 19416672 DOI: 10.1016/j.expneurol.2009.01.017] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 01/23/2009] [Accepted: 01/27/2009] [Indexed: 10/21/2022]
Abstract
Acute intermittent hypoxia (AIH) elicits a form of respiratory plasticity known as long-term facilitation (LTF). We hypothesized that: 1) daily AIH (dAIH) preconditioning enhances phrenic and hypoglossal (XII) LTF in a rat strain with low constitutive LTF expression; 2) dAIH induces brain-derived neurotrophic factor (BDNF), a critical protein for phrenic LTF (pLTF) in the cervical spinal cord; and 3) dAIH increases post-AIH extracellular regulated kinase (ERK) activation. Phrenic and XII motor output were monitored in anesthetized dAIH- or sham-treated Brown Norway rats with and without acute AIH. pLTF was observed in both sham (18+/-9% baseline; 60 min post-hypoxia; p<0.05; n=18) and dAIH treated rats (37+/-8%; p<0.05; n=14), but these values were not significantly different (p=0.13). XII LTF was not observed in sham-treated rats (4+/-5%), but was revealed in dAIH pretreated rats (48+/-18%; p<0.05). dAIH preconditioning increased basal ventral cervical BDNF protein levels (24+/-8%; p<0.05), but had no significant effect on ERK phosphorylation. AIH increased BDNF in sham (25+/-8%; p<0.05), but not dAIH-pretreated rats (-7+/-4%), and had complex effects on ERK phosphorylation (ERK2 increased in shams whereas ERK1 increased in dAIH-treated rats). Thus, dAIH elicits metaplasticity in LTF, revealing XII LTF in a rat strain with no constitutive XII LTF expression. Increased BDNF synthesis may no longer be necessary for phrenic LTF following dAIH preconditioning since BDNF concentration is already elevated.
Collapse
Affiliation(s)
- Julia E R Wilkerson
- Department of Comparative Biosciences, University of Wisconsin, School of Veterinary Medicine, Madison, WI 53706, USA
| | | |
Collapse
|
43
|
McGuire M, Tartar JL, Cao Y, McCarley RW, White DP, Strecker RE, Ling L. Sleep fragmentation impairs ventilatory long-term facilitation via adenosine A1 receptors. J Physiol 2008; 586:5215-29. [PMID: 18787037 DOI: 10.1113/jphysiol.2008.158121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Sleep fragmentation (SF), a primary feature of obstructive sleep apnoea (OSA), impairs hippocampal long-term potentiation and causes cognitive/attention deficits. However, its influence upon respiratory control has hardly been studied. This study examined the effect of SF on ventilatory long-term facilitation (LTF, a persistent augmentation of respiratory activity after episodic hypoxia) and the hypoxic ventilatory response (HVR), and investigated the role of adenosine A1 receptors in these SF effects in conscious adult male Sprague-Dawley rats. SF, confirmed by sleep architecture recordings, was achieved by periodic, forced locomotion in a rotating drum (30 s rotation/90 s stop for 24 h). LTF, elicited by five episodes of 5 min poikilocapnic hypoxia (10% O2) with 5 min intervals, was measured by plethysmography. Resting ventilation and metabolic rate were unchanged, HVR was reduced (150.6 +/- 3.5% versus 110.4 +/- 12.3%) and LTF was eliminated (22.6 +/- 0.5% versus -0.1 +/- 1.3%) shortly after 24 h SF. The SF-induced impairments were SF duration dependent, and completely reversible as HVR (< 24 h) and LTF (< 48 h) returned spontaneously to their pre-SF values. The SF-impaired HVR was improved (130.3 +/- 4.2%) and SF-eliminated LTF was restored (19.6 +/- 0.9%) by systemic injection of the adenosine A1 receptor antagonist 8-CPT (2.5 mg kg(-1)) approximately 30 min before LTF elicitation. Both HVR and LTF were also similarly impaired by 24 h total sleep deprivation or 24 h repeated cage tapping-induced SF, but not by a 24 h locomotion control protocol for SF. Collectively, these data suggest that: (1) 24 h SF impairs LTF and poikilocapnic HVR; (2) these impairments require A1 receptors; and (3) SF of OSA may exacerbate OSA via impaired ventilatory control mechanisms.
Collapse
Affiliation(s)
- Michelle McGuire
- Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
McGuire M, Liu C, Cao Y, Ling L. Formation and maintenance of ventilatory long-term facilitation require NMDA but not non-NMDA receptors in awake rats. J Appl Physiol (1985) 2008; 105:942-50. [PMID: 18583381 DOI: 10.1152/japplphysiol.01274.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-methyl-d-aspartate (NMDA) receptor antagonism in the phrenic motonucleus area eliminates phrenic long-term facilitation (pLTF; a persistent augmentation of phrenic nerve activity after episodic hypoxia) in anesthetized rats. However, whether NMDA antagonism can eliminate ventilatory LTF (vLTF) in awake rats is unclear. The role of non-NMDA receptors in LTF is also unknown. Serotonin receptor antagonism before, but not after, episodic hypoxia eliminates pLTF, suggesting that serotonin receptors are required for induction, but not maintenance, of pLTF. However, because NMDA and non-NMDA ionotropic glutamate receptors are directly involved in mediating the inspiratory drive to phrenic, hypoglossal, and intercostal motoneurons, we hypothesized that these receptors are required for both formation and maintenance of vLTF. vLTF, induced by five episodes of 5-min poikilocapnic hypoxia (10% O(2)) with 5-min normoxia intervals, was measured with plethysmography in conscious adult male Sprague-Dawley rats. Either (+/-)-2-amino-5-phosphonovaleric acid (APV; NMDA antagonist, 1.5 mg/kg) or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; non-NMDA antagonist, 10 mg/kg) was systemically (ip) injected approximately 30 min before hypoxia. APV was also injected immediately after or 20 min after episodic hypoxia in additional groups. As control, vehicle was similarly injected in each rat 1-2 days before. Regardless of being injected before or after episodic hypoxia, vehicle did not alter vLTF ( approximately 23%), whereas APV eliminated vLTF while having little effect on baseline ventilation or hypoxic ventilatory response. In contrast, CNQX enhanced vLTF ( approximately 34%) while decreasing baseline ventilation. Collectively, these results suggest that activation of NMDA but not non-NMDA receptors is necessary for formation and maintenance of vLTF in awake rats.
Collapse
Affiliation(s)
- Michelle McGuire
- Div. of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | |
Collapse
|