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Osman AM, Mukherjee S, Altree TJ, Delbeck M, Gehring D, Hahn M, Lang T, Xing C, Muller T, Weimann G, Eckert DJ. Topical Potassium Channel Blockage Improves Pharyngeal Collapsibility: A Translational, Placebo-Controlled Trial. Chest 2022; 163:953-965. [PMID: 36435266 DOI: 10.1016/j.chest.2022.11.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 10/06/2022] [Accepted: 11/02/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Potassium channel inhibition has been identified in animal models as a potential target to increase pharyngeal dilator muscle activity and to treat OSA. However, these findings have not yet been translated to humans. RESEARCH QUESTION Does a novel, potent, TWIK-related acid-sensitive K+ (TASK) 1/3 channel antagonist, BAY2586116, improve pharyngeal collapsibility in pigs and humans, and secondarily, what is the optimal dose and method of topical application? STUDY DESIGN AND METHODS In the preclinical study, pharyngeal muscle activity and upper-airway collapsibility via transient negative pressure application was quantified in 13 anesthetized pigs during administration of placebo, 0.3 μg, 3 μg, and 30 μg nasal drops of BAY2586116. In the clinical study, 12 people with OSA instrumented with polysomnography equipment, an epiglottic pressure catheter, pneumotachograph, and nasal mask to monitor sleep and breathing performed up to four detailed upper airway sleep physiology studies. Participants received BAY2586116 or placebo nasal spray (160 μg) before sleep via a double-masked, randomized, crossover design. Most participants also returned for three additional overnight visits: (1) nasal drops (160 μg), (2) half-dose nasal spray (80 μg), and (3) direct endoscopic application (160 μg). The upper-airway critical closing pressure during sleep was quantified at each visit. RESULTS Consistent and sustained improvements in pharyngeal collapsibility to negative pressure were found with 3 and 30 μg of BAY2586116 vs placebo in pigs. Similarly, BAY2586116 improved pharyngeal collapsibility by an average of approximately 2 cm H2O vs placebo, regardless of topical application method and dose (P < .008, mixed model) in participants with OSA. INTERPRETATION Acute topical application of BAY2586116 improves upper-airway collapsibility in anesthetized pigs and sleeping humans with OSA. These novel physiologic findings highlight the therapeutic potential to target POTASSIUM channel mechanisms to treat OSA. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT04236440; URL: www. CLINICALTRIALS gov.
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Affiliation(s)
- Amal M Osman
- Adelaide Institute for Sleep Health and FHMRI Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide.
| | - Sutapa Mukherjee
- Adelaide Institute for Sleep Health and FHMRI Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide; Respiratory and Sleep Service, Southern Adelaide Local Health Network, SA Health, SA, Australia
| | - Thomas J Altree
- Adelaide Institute for Sleep Health and FHMRI Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide; Respiratory and Sleep Service, Southern Adelaide Local Health Network, SA Health, SA, Australia
| | - Martina Delbeck
- Research & Development, Pharmaceuticals, Bayer AG, Wuppertal
| | | | - Michael Hahn
- Research & Development, Pharmaceuticals, Bayer AG, Wuppertal
| | - Tina Lang
- Research & Development, Pharmaceuticals, Bayer AG, Wuppertal
| | - Charles Xing
- Research & Development, Pharmaceuticals, Bayer AG, Wuppertal
| | - Thomas Muller
- Research & Development, Pharmaceuticals, Bayer AG, Wuppertal
| | - Gerrit Weimann
- Research & Development, Pharmaceuticals, Bayer AG, Wuppertal
| | - Danny J Eckert
- Adelaide Institute for Sleep Health and FHMRI Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide
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Carberry JC, Burke PGR, Osman AM, Jugé L, Toson B, Gandevia SC, Butler JE, Bilston LE, Eckert DJ. Regional genioglossus reflex responses to negative pressure pulses in people with obstructive sleep apnea. J Appl Physiol (1985) 2022; 133:755-765. [PMID: 35771222 DOI: 10.1152/japplphysiol.00083.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tongue and upper airway dilator muscle movement patterns during quiet breathing vary in people with obstructive sleep apnea (OSA). Many patients have inadequate or counterproductive responses to inspiratory negative airway pressure that likely contributes to their OSA. This may be due, at least in part, to inadequate or non-homogeneous reflex drive to different regions of the largest upper airway dilator, genioglossus. To investigate potential regional heterogeneity of genioglossus reflex responses in OSA, brief suction pulses were applied via nasal breathing mask and electromyogram (EMG) was recorded in 4 regions (anterior oblique, anterior horizontal, posterior oblique, posterior horizontal) using intramuscular fine wire electrodes in 15 people with OSA. Genioglossus short-latency reflex excitation amplitude had regional heterogeneity (horizontal vs. oblique regions) when expressed in absolute units but homogeneity when normalized as a percentage of the immediate (100ms) pre-stimulus EMG. Regional variability in reflex morphology (excitation and inhibition) was present in one third of participants. Minimum cross-sectional area (CSA) of the pharyngeal airway quantified using MRI and may be related to the amplitude of the short-latency reflex response to negative pressure such that we found that people with a smaller CSA tended to have greater reflex amplitude (e.g. horizontal region r2=0.41, p=0.01). These findings highlight the complexity of genioglossus reflex control, the potential for regional heterogeneity and the functional importance of upper airway anatomy in mediating genioglossus reflex responses to rapid changes in negative pressure in OSA.
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Affiliation(s)
- Jayne C Carberry
- Adelaide Institute for Sleep Health, Flinders University, Adelaide, SA, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,University College Dublin, School of Medicine, Ireland
| | - Peter George Redmayne Burke
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia.,Department of Biomedical Sciences, Macquarie University, Australia
| | - Amal M Osman
- Adelaide Institute for Sleep Health, Flinders University, Adelaide, SA, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia
| | - Lauriane Jugé
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia
| | - Barbara Toson
- Adelaide Institute for Sleep Health, Flinders University, Adelaide, SA, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia
| | - Danny J Eckert
- Adelaide Institute for Sleep Health, Flinders University, Adelaide, SA, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,UNSW Sydney, Randwick, Australia
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Altree TJ, Eckert DJ. Obstructive sleep apnea endotypes and their postoperative relevance. Int Anesthesiol Clin 2022; 60:1-7. [PMID: 35125480 DOI: 10.1097/aia.0000000000000357] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Thomas J Altree
- Adelaide Institute for Sleep Health, Flinders Health and Medical Research Institute, Flinders University, Bedford Park, South Australia, Australia
- Respiratory and Sleep Services, Flinders Medical Centre, Southern Adelaide Local Health Network, Bedford Park, South Australia, Australia
| | - Danny J Eckert
- Adelaide Institute for Sleep Health, Flinders Health and Medical Research Institute, Flinders University, Bedford Park, South Australia, Australia
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Myoelectric characteristics of tensor palatini and collapsibility of upper airway in OSA patients with different phenotypes under DISE. Eur Arch Otorhinolaryngol 2021; 279:425-432. [PMID: 34052864 DOI: 10.1007/s00405-021-06795-5] [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: 01/06/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE This study aims to evaluate the combination of myoelectric characteristics of tensor palatini muscle (TP) and collapsibility of upper airway in obstructive sleep apnea (OSA) patients with different external phenotypes of collapse pattern at velum level under drug-induced sleep endoscopy (DISE). STUDY DESIGN Case series with planned data collection. SETTING Operation room. SUBJECTS AND METHODS 36 mainly collapse pattern at velum level OSA subjects underwent DISE with synchronous tensor palatini electromyograms (TP EMG), and polysomnography (ALICE 6). According to the phenotype of collapse pattern at velum level in DISE, the subjects were divided into group 1 (concentric collapse), group 2 (anteroposterior collapse), and group 3 (lateral collapse). Each group consisted of 13, 14, and 9 subjects, respectively, and was observed the electromyographic indexes at awake, sleep onset, during apnea and the third respiratory cycle after apnea. The active and passive upper airway critical closing pressure (Pcrit) of each group were measured at the same time, and the difference of neuromuscular response between different groups was evaluated. RESULTS In tonic TPEMG, group 1 showed the highest value during awake and sleep onset, while group 2 was the highest during apnea and after apnea. In peak TPEMG, group 1 showed the highest value during awake. Group 2 showed the highest value during other states. In passive Pcrit and D value (difference between passive Pcrit and active Pcrit), group 2 was the highest, while group 1 was the highest in active Pcrit. Difference was statistically significant. CONCLUSIONS Under different states of awake, sleep onset, apnea and after apnea, the response force of tensor palatini muscle of OSA subjects with different phenotypes under DISE was different. Group 1 showed the highest EMG values only when awake and sleep onset, and it was most prone to collapse. Group 2 had the highest anatomical load (passive Pcrit) and the highest neuromuscular compensatory effect (D value).
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Ruehland WR, Rochford PD, Pierce RJ, Trinder J, Jordan AS, Cori JM, O'Donoghue FJ. Genioglossus muscle responses to resistive loads in severe OSA patients and healthy control subjects. J Appl Physiol (1985) 2019; 127:1586-1598. [PMID: 31647723 DOI: 10.1152/japplphysiol.00186.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aimed to determine whether there is impairment of genioglossus neuromuscular responses to small negative pressure respiratory stimuli, close to the conscious detection threshold, in obstructive sleep apnea (OSA). We compared genioglossus electromyogram (EMGgg) responses to midinspiratory resistive loads of varying intensity (≈1.2-6.2 cmH2O·L-1·s), delivered via a nasal mask, between 16 severe OSA and 17 control participants while the subjects were awake and in a seated upright position. We examined the relationship between stimulus intensity and peak EMGgg amplitude in a 200-ms poststimulus window and hypothesized that OSA patients would have an increased activation threshold and reduced sensitivity in the relationship between EMGgg activation and stimulus intensity. There was no significant difference between control and OSA participants in the threshold (P = 0.545) or the sensitivity (P = 0.482) of the EMGgg amplitude vs. stimulus intensity relationship, where change in epiglottic pressure relative to background epiglottic pressure represented stimulus intensity. These results do not support the hypothesis that deficits in neuromuscular response to negative upper airway pressure exist in OSA during wakefulness; however, the results are likely influenced by a counterintuitive and novel genioglossus muscle suppression response observed in a significant proportion of both OSA and healthy control participants. This suppression response may relate to the inhibition seen in inspiratory muscles such as the diaphragm in response to sudden-onset negative pressure, and its presence provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.NEW & NOTEWORTHY Our study used a novel midinspiratory resistive load stimulus to study upper airway neuromuscular responses to negative pressure during wakefulness in obstructive sleep apnea (OSA). Although no differences were found between OSA and healthy groups, the study uncovered a novel and unexpected suppression of neuromuscular activity in a large proportion of both OSA and healthy participants. The unusual response provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.
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Affiliation(s)
- Warren R Ruehland
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Victoria, Australia
| | - Peter D Rochford
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Robert J Pierce
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Victoria, Australia
| | - John Trinder
- School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Amy S Jordan
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Jennifer M Cori
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Fergal J O'Donoghue
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Victoria, Australia
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Sistla SK, Paramasivan VK, Agrawal V. Anatomic and Pathophysiologic Considerations in Surgical Treatment of Obstructive Sleep Apnea. Sleep Med Clin 2019; 14:21-31. [PMID: 30709530 DOI: 10.1016/j.jsmc.2018.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Evaluation of the upper airway is key for a successful surgical management. Proper evaluation can be done only with a good understanding of the anatomy and pathophysiology of the upper airway. The authors discuss surgical anatomy from a soft tissue and bony perspective in detail along with its clinical implications. The complex interaction among pharyngeal dilator tone, arousal threshold, respiratory control instability, and changes in lung volume during sleep play an important role in obstructive sleep apnea. Because all the anatomic and physiologic characteristics discussed have genetic predisposition, gene therapy may play a pivotal role in the future.
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Affiliation(s)
- Srinivas Kishore Sistla
- Department of ENT, Star Hospital, Block B, Road Number 10, Banjara Hills, Hyderabad 500034, Telangana, India.
| | - Vijaya Krishnan Paramasivan
- Department of Snoring & Sleep Disorders, Madras ENT Research Foundation, 1, Ist Cross Street, Off II Main Road, Raja Annamalaipuram, Chennai 600028, Tamil Nadu, India
| | - Vikas Agrawal
- Department of ENT, Specialty ENT Hospital, Kandivali East, Mumbai 400101, Maharashtra, India
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Wijesuriya NS, Gainche L, Jordan AS, Berlowitz DJ, LeGuen M, Rochford PD, O'Donoghue FJ, Ruehland WR, Carberry JC, Butler JE, Eckert DJ. Genioglossus reflex responses to negative upper airway pressure are altered in people with tetraplegia and obstructive sleep apnoea. J Physiol 2018; 596:2853-2864. [PMID: 29658103 DOI: 10.1113/jp275222] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/07/2018] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Protective reflexes in the throat area (upper airway) are crucial for breathing. Impairment of these reflexes can cause breathing problems during sleep such as obstructive sleep apnoea (OSA). OSA is very common in people with spinal cord injury for unknown reasons. This study shows major changes in protective reflexes that serve to keep the upper airway open in response to suction pressures in people with tetraplegia and OSA. These results help us understand why OSA is so common in people with tetraplegia and provide new insight into how protective upper airway reflexes work more broadly. ABSTRACT More than 60% of people with tetraplegia have obstructive sleep apnoea (OSA). However, the specific causes are unknown. Genioglossus, the largest upper-airway dilator muscle, is important in maintaining upper-airway patency. Impaired genioglossus muscle function following spinal cord injury may contribute to OSA. This study aimed to determine if genioglossus reflex responses to negative upper-airway pressure are altered in people with OSA and tetraplegia compared to non-neurologically impaired able-bodied individuals with OSA. Genioglossus reflex responses measured via intramuscular electrodes to ∼60 brief (250 ms) pulses of negative upper-airway pressure (∼-15 cmH2 O at the mask) were compared between 13 participants (2 females) with tetraplegia plus OSA and 9 able-bodied controls (2 females) matched for age and OSA severity. The initial short-latency excitatory reflex response was absent in 6/13 people with tetraplegia and 1/9 controls. Genioglossus reflex inhibition in the absence of excitation was observed in three people with tetraplegia and none of the controls. When the excitatory response was present, it was significantly delayed in the tetraplegia group compared to able-bodied controls: excitation onset latency (mean ± SD) was 32 ± 16 vs. 18 ± 9 ms, P = 0.045; peak excitation latency was 48 ± 17 vs. 33 ± 8 ms, P = 0.038. However, when present, amplitude of the excitation response was not different between groups, 195 ± 26 vs. 219 ± 98% at baseline, P = 0.55. There are major differences in genioglossus reflex morphology and timing in response to rapid changes in airway pressure in people with tetraplegia and OSA. Altered genioglossus function may contribute to the increased risk of OSA in people with tetraplegia. The precise mechanisms mediating these differences are unknown.
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Affiliation(s)
| | - Laura Gainche
- University of Melbourne, Melbourne, Australia.,Institute for Breathing and Sleep (IBAS), Melbourne, Australia
| | - Amy S Jordan
- University of Melbourne, Melbourne, Australia.,Institute for Breathing and Sleep (IBAS), Melbourne, Australia
| | - David J Berlowitz
- University of Melbourne, Melbourne, Australia.,Institute for Breathing and Sleep (IBAS), Melbourne, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Melbourne, Australia
| | - Mariannick LeGuen
- University of Melbourne, Melbourne, Australia.,Institute for Breathing and Sleep (IBAS), Melbourne, Australia
| | - Peter D Rochford
- Institute for Breathing and Sleep (IBAS), Melbourne, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Melbourne, Australia
| | - Fergal J O'Donoghue
- University of Melbourne, Melbourne, Australia.,Institute for Breathing and Sleep (IBAS), Melbourne, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Melbourne, Australia
| | - Warren R Ruehland
- University of Melbourne, Melbourne, Australia.,Institute for Breathing and Sleep (IBAS), Melbourne, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Melbourne, Australia
| | - Jayne C Carberry
- Neuroscience Research Australia (NeuRA), Randwick, NSW, Australia.,University of New South Wales, Syndney, Australia
| | - Jane E Butler
- Neuroscience Research Australia (NeuRA), Randwick, NSW, Australia.,University of New South Wales, Syndney, Australia
| | - Danny J Eckert
- Neuroscience Research Australia (NeuRA), Randwick, NSW, Australia.,University of New South Wales, Syndney, Australia
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8
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Phenotypic approaches to obstructive sleep apnoea – New pathways for targeted therapy. Sleep Med Rev 2018; 37:45-59. [DOI: 10.1016/j.smrv.2016.12.003] [Citation(s) in RCA: 225] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/30/2016] [Accepted: 12/08/2016] [Indexed: 02/01/2023]
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Abstract
The prevalence of obstructive sleep apnea (OSA) continues to rise. So too do the health, safety, and economic consequences. On an individual level, the causes and consequences of OSA can vary substantially between patients. In recent years, four key contributors to OSA pathogenesis or "phenotypes" have been characterized. These include a narrow, crowded, or collapsible upper airway "anatomical compromise" and "non-anatomical" contributors such as ineffective pharyngeal dilator muscle function during sleep, a low threshold for arousal to airway narrowing during sleep, and unstable control of breathing (high loop gain). Each of these phenotypes is a target for therapy. This review summarizes the latest knowledge on the different contributors to OSA with a focus on measurement techniques including emerging clinical tools designed to facilitate translation of new cause-driven targeted approaches to treat OSA. The potential for some of the specific pathophysiological causes of OSA to drive some of the key symptoms and consequences of OSA is also highlighted.
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Affiliation(s)
- Amal M Osman
- Neuroscience Research Australia (NeuRA).,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sophie G Carter
- Neuroscience Research Australia (NeuRA).,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jayne C Carberry
- Neuroscience Research Australia (NeuRA).,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Danny J Eckert
- Neuroscience Research Australia (NeuRA).,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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10
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Edwards BA, Eckert DJ, Jordan AS. Obstructive sleep apnoea pathogenesis from mild to severe: Is it all the same? Respirology 2016; 22:33-42. [PMID: 27699919 DOI: 10.1111/resp.12913] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/31/2016] [Indexed: 12/14/2022]
Abstract
Obstructive sleep apnoea (OSA) is a common disorder caused by not only an impaired upper airway anatomy (i.e. anatomically narrow/collapsible airway), but also by several non-anatomical factors. In this review, we summarise what is known about how each of the pathological factors that cause OSA vary according to disease severity as measured by the apnoea-hypopnoea index. Our synthesis of the available literature indicates that most of the key factors that cause OSA vary with disease severity. However, there is substantial heterogeneity such that the relative contribution of each of these traits varies both between patients and within different severities of disease. These differences likely contribute to variable efficacy of many non-continuous positive airway pressure treatments and inconsistencies in responses with regard to different OSA severities at baseline.
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Affiliation(s)
- Bradley A Edwards
- Sleep and Circadian Medicine Laboratory, Department of Physiology, Monash University, Melbourne, Victoria, Australia.,School of Psychological Sciences, Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Danny J Eckert
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,University of New South Wales, Sydney, New South Wales, Australia
| | - Amy S Jordan
- Department of Psychology, University of Melbourne, Melbourne, Victoria, Australia
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11
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Carberry JC, Hensen H, Fisher LP, Saboisky JP, Butler JE, Gandevia SC, Eckert DJ. Mechanisms contributing to the response of upper-airway muscles to changes in airway pressure. J Appl Physiol (1985) 2015; 118:1221-8. [DOI: 10.1152/japplphysiol.01103.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/02/2015] [Indexed: 11/22/2022] Open
Abstract
This study assessed the effects of inhaled lignocaine to reduce upper airway surface mechanoreceptor activity on 1) basal genioglossus and tensor palatini EMG, 2) genioglossus reflex responses to large pulses (∼10 cmH2O) of negative airway pressure, and 3) upper airway collapsibility in 15 awake individuals. Genioglossus and tensor palatini muscle EMG and airway pressures were recorded during quiet nasal breathing and during brief pulses (250 ms) of negative upper-airway pressure. Lignocaine reduced peak inspiratory (5.6 ± 1.5 vs. 3.8 ± 1.1% maximum; mean ± SE, P < 0.01) and tonic (2.8 ± 0.8 vs. 2.1 ± 0.7% maximum; P < 0.05) genioglossus EMG during quiet breathing but had no effect on tensor palatini EMG (5.0 ± 0.8 vs. 5.0 ± 0.5% maximum; P = 0.97). Genioglossus reflex excitation to negative pressure pulses decreased after anesthesia (60.9 ± 20.7 vs. 23.6 ± 5.2 μV; P < 0.05), but not when expressed as a percentage of the immediate prestimulus baseline. Reflex excitation was closely related to the change in baseline EMG following lignocaine ( r2 = 0.98). A short-latency genioglossus reflex to rapid increases from negative to atmospheric pressure was also observed. The upper airway collapsibility index (%difference) between nadir choanal and epiglottic pressure increased after lignocaine (17.8 ± 3.7 vs. 28.8 ± 7.5%; P < 0.05). These findings indicate that surface receptors modulate genioglossus but not tensor palatini activity during quiet breathing. However, removal of input from surface mechanoreceptors has minimal effect on genioglossus reflex responses to large (∼10 cmH2O), sudden changes in airway pressure. Changes in pressure rather than negative pressure per se can elicit genioglossus reflex responses. These findings challenge previous views and have important implications for upper airway muscle control.
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Affiliation(s)
- Jayne C. Carberry
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
| | - Hanna Hensen
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
| | - Lauren P. Fisher
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
| | - Julian P. Saboisky
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
| | - Jane E. Butler
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
| | - Danny J. Eckert
- Neuroscience Research Australia (NeuRA) and University of New South Wales, Sydney, New South Wales, Australia
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12
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Abstract
Sensory nerves innervating the lung and airways play an important role in regulating various cardiopulmonary functions and maintaining homeostasis under both healthy and disease conditions. Their activities conducted by both vagal and sympathetic afferents are also responsible for eliciting important defense reflexes that protect the lung and body from potential health-hazardous effects of airborne particulates and chemical irritants. This article reviews the morphology, transduction properties, reflex functions, and respiratory sensations of these receptors, focusing primarily on recent findings derived from using new technologies such as neural immunochemistry, isolated airway-nerve preparation, cultured airway neurons, patch-clamp electrophysiology, transgenic mice, and other cellular and molecular approaches. Studies of the signal transduction of mechanosensitive afferents have revealed a new concept of sensory unit and cellular mechanism of activation, and identified additional types of sensory receptors in the lung. Chemosensitive properties of these lung afferents are further characterized by the expression of specific ligand-gated ion channels on nerve terminals, ganglion origin, and responses to the action of various inflammatory cells, mediators, and cytokines during acute and chronic airway inflammation and injuries. Increasing interest and extensive investigations have been focused on uncovering the mechanisms underlying hypersensitivity of these airway afferents, and their role in the manifestation of various symptoms under pathophysiological conditions. Several important and challenging questions regarding these sensory nerves are discussed. Searching for these answers will be a critical step in developing the translational research and effective treatments of airway diseases.
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Affiliation(s)
- Lu-Yuan Lee
- Department of Physiology, University of Kentucky, Lexington, Kentucky
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13
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Schwab RJ, Kim C, Siegel L, Keenan BT, Black J, Farid-Moayer M, Podmore J, Vaska M. Examining the mechanism of action of a new device using oral pressure therapy for the treatment of obstructive sleep apnea. Sleep 2014; 37:1237-47. [PMID: 25061252 DOI: 10.5665/sleep.3846] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES The objective of this study was to explore the mechanism of action of the oral pressure therapy (OPT) device, a new treatment for sleep apnea. DESIGN Case series. SETTING Academic medical center. PATIENTS Fifteen subjects with sleep apnea who had been successfully treated (responders) with the OPT device and 4 subjects who were not successfully treated (non-responders) with the OPT device. INTERVENTIONS All subjects underwent a MRI (without the device, with the device in place without vacuum and with the device in place with vacuum) to examine the biomechanical changes associated with the OPT device. MEASUREMENTS AND RESULTS Oral pressure therapy significantly (P = 0.002) increased the size of the retropalatal airway in both the lateral and anterior-posterior dimensions by moving the soft palate anteriorly and superiorly and the anterior-superior segment of the tongue forward, toward the teeth. The percentage and absolute increase in the cross-sectional area of the retropalatal region, the superior movement of the soft palate, and the anterior displacement of the tongue were significantly greater in the responders than in the non-responders. In responders, there were significant increases in the mean (P = 0.002), maximum (P = 0.0002), and minimum (P = 0.04) cross-sectional areas of the retropalatal region with the OPT device. However, in the retroglossal region, airway caliber decreased with the OPT device. CONCLUSIONS In those who responded to oral pressure therapy, it increased airway caliber in the retropalatal region by moving the soft palate anteriorly and superiorly and the anterior-superior segment of the tongue forward. CITATION Schwab RJ, Kim C, Siegel L, Keenan BT, Black J, Farid-Moayer M, Podmore J, Vaska M. Examining the mechanism of action of a new device using oral pressure therapy for the treatment of obstructive sleep apnea.
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Affiliation(s)
- Richard J Schwab
- Division of Sleep Medicine, Pulmonary Allergy and Critical Care Division and Center for Sleep & Circadian Neurobiology, Philadelphia PA
| | - C Kim
- Division of Sleep Medicine, Pulmonary Allergy and Critical Care Division and Center for Sleep & Circadian Neurobiology, Philadelphia PA
| | - Lawrence Siegel
- Stanford University School of Medicine, Stanford, CA ; ApniCure, Redwood City CA
| | - B T Keenan
- Division of Sleep Medicine, Pulmonary Allergy and Critical Care Division and Center for Sleep & Circadian Neurobiology, Philadelphia PA
| | - Jed Black
- Stanford University School of Medicine, Stanford, CA
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Eckert DJ, Malhotra A, Wellman A, White DP. Trazodone increases the respiratory arousal threshold in patients with obstructive sleep apnea and a low arousal threshold. Sleep 2014; 37:811-9. [PMID: 24899767 PMCID: PMC4044741 DOI: 10.5665/sleep.3596] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES The effect of common sedatives on upper airway physiology and breathing during sleep in obstructive sleep apnea (OSA) has been minimally studied. Conceptually, certain sedatives may worsen OSA in some patients. However, sleep and breathing could improve with certain sedatives in patients with OSA with a low respiratory arousal threshold. This study aimed to test the hypothesis that trazodone increases the respiratory arousal threshold in patients with OSA and a low arousal threshold. Secondary aims were to examine the effects of trazodone on upper airway dilator muscle activity, upper airway collapsibility, and breathing during sleep. DESIGN Patients were studied on 4 separate nights according to a within-subjects cross-over design. SETTING Sleep physiology laboratory. PATIENTS Seven patients with OSA and a low respiratory arousal threshold. INTERVENTIONS In-laboratory polysomnograms were obtained at baseline and after 100 mg of trazodone was administered, followed by detailed overnight physiology experiments under the same conditions. During physiology studies, continuous positive airway pressure was transiently lowered to measure arousal threshold (negative epiglottic pressure prior to arousal), dilator muscle activity (genioglossus and tensor palatini), and upper airway collapsibility (Pcrit). MEASUREMENTS AND RESULTS Trazodone increased the respiratory arousal threshold by 32 ± 6% (-11.5 ± 1.4 versus -15.3 ± 2.2 cmH2O, P < 0.01) but did not alter the apnea-hypopnea index (39 ± 12 versus 39 ± 11 events/h sleep, P = 0.94). Dilator muscle activity and Pcrit also did not systematically change with trazodone. CONCLUSIONS Trazodone increases the respiratory arousal threshold in patients with obstructive sleep apnea and a low arousal threshold without major impairment in dilator muscle activity or upper airway collapsibility. However, the magnitude of change in arousal threshold was insufficient to overcome the compromised upper airway anatomy in these patients.
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Affiliation(s)
- Danny J. Eckert
- Brigham and Women's Hospital, Division of Sleep Medicine, Sleep Disorders Program and Harvard Medical School, Boston, MA
- Neuroscience Research Australia (NeuRA), and the School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Atul Malhotra
- Brigham and Women's Hospital, Division of Sleep Medicine, Sleep Disorders Program and Harvard Medical School, Boston, MA
- Pulmonary and Critical Care Division, University of California San Diego, La Jolla, CA
| | - Andrew Wellman
- Brigham and Women's Hospital, Division of Sleep Medicine, Sleep Disorders Program and Harvard Medical School, Boston, MA
| | - David P. White
- Brigham and Women's Hospital, Division of Sleep Medicine, Sleep Disorders Program and Harvard Medical School, Boston, MA
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Eckert DJ, Lo YL, Saboisky JP, Jordan AS, White DP, Malhotra A. Sensorimotor function of the upper-airway muscles and respiratory sensory processing in untreated obstructive sleep apnea. J Appl Physiol (1985) 2011; 111:1644-53. [PMID: 21885797 PMCID: PMC3233889 DOI: 10.1152/japplphysiol.00653.2011] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 08/30/2011] [Indexed: 11/22/2022] Open
Abstract
Numerous studies have demonstrated upper-airway neuromuscular abnormalities during wakefulness in snorers and obstructive sleep apnea (OSA) patients. However, the functional role of sensorimotor impairment in OSA pathogenesis/disease progression and its potential effects on protective upper-airway reflexes, measures of respiratory sensory processing, and force characteristics remain unclear. This study aimed to gain physiological insight into the potential role of sensorimotor impairment in OSA pathogenesis/disease progression by comparing sensory processing properties (respiratory-related evoked potentials; RREP), functionally important protective reflexes (genioglossus and tensor palatini) across a range of negative pressures (brief pulses and entrained iron lung ventilation), and tongue force and time to task failure characteristics between 12 untreated OSA patients and 13 controls. We hypothesized that abnormalities in these measures would be present in OSA patients. Upper-airway reflexes (e.g., genioglossus onset latency, 20 ± 1 vs. 19 ± 2 ms, P = 0.82), early RREP components (e.g., P1 latency 25 ± 2 vs. 25 ± 1 ms, P = 0.78), and the slope of epiglottic pressure vs. genioglossus activity during iron lung ventilation (-0.68 ± 1.0 vs. -0.80 ± 2.0 cmH(2)O/%max, P = 0.59) were not different between patients and controls. Maximal tongue protrusion force was greater in OSA patients vs. controls (35 ± 2 vs. 27 ± 2 N, P < 0.01), but task failure occurred more rapidly (149 ± 24 vs. 254 ± 23 s, P < 0.01). Upper-airway protective reflexes across a range of negative pressures as measured by electromyography and the early P1 component of the RREP are preserved in OSA patients during wakefulness. Consistent with an adaptive training effect, tongue protrusion force is increased, not decreased, in untreated OSA patients. However, OSA patients may be vulnerable to fatigue of upper-airway dilator muscles, which could contribute to disease progression.
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Affiliation(s)
- Danny J Eckert
- Brigham and Women's Hospital, Div. of Sleep Medicine, Sleep Disorders Program, Boston, MA 02115, USA.
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