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Hobbins L, Hunter S, Gaoua N, Girard O. Short-Term Perceptually Regulated Interval-Walk Training in Hypoxia and Normoxia in Overweight-to-Obese Adults. JOURNAL OF SPORTS SCIENCE AND MEDICINE 2021; 20:45-51. [PMID: 33707985 DOI: 10.52082/jssm.2021.45] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/23/2020] [Indexed: 12/26/2022]
Abstract
We compared the effects of short-term, perceptually regulated training using interval-walking in hypoxia vs. normoxia on health outcomes in overweight-to-obese individuals. Sixteen adults (body mass index = 33 ± 3 kg·m-2) completed eight interval-walk training sessions (15 × 2 min walking at a rating of perceived exertion of 14 on the 6-20 Borg scale; rest = 2 min) either in hypoxia (FiO2 = 13.0%) or normoxia during two weeks. Treadmill velocity did not differ between conditions or over time (p > 0.05). Heart rate was higher in hypoxia (+10 ± 3%; p = 0.04) during the first session and this was consistent within condition across the training sessions (p > 0.05). Similarly, arterial oxygen saturation was lower in hypoxia than normoxia (83 ± 1% vs. 96 ± 1%, p < 0.05), and did not vary over time (p > 0.05). After training, perceived mood state (+11.8 ± 2.7%, p = 0.06) and exercise self-efficacy (+10.6 ± 4.1%, p = 0.03) improved in both groups. Body mass (p = 0.55), systolic and diastolic blood pressure (p = 0.19 and 0.07, respectively) and distance covered during a 6-min walk test (p = 0.11) did not change from pre- to post-tests. Short term (2-week) perceptually regulated interval-walk training sessions with or without hypoxia had no effect on exercise-related sensations, health markers and functional performance. This mode and duration of hypoxic conditioning does not appear to modify the measured cardiometabolic risk factors or improve exercise tolerance in overweight-to-obese individuals.
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Affiliation(s)
- Liam Hobbins
- Sport and Exercise Science Research Centre (SESRC), London South Bank University, London, UK
| | - Steve Hunter
- Sport and Exercise Science Research Centre (SESRC), London South Bank University, London, UK
| | - Nadia Gaoua
- Sport and Exercise Science Research Centre (SESRC), London South Bank University, London, UK
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, Western Australia, Australia
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152
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Burtscher J, Syed MMK, Lashuel HA, Millet GP. Hypoxia Conditioning as a Promising Therapeutic Target in Parkinson's Disease? Mov Disord 2021; 36:857-861. [DOI: 10.1002/mds.28544] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 02/06/2023] Open
Affiliation(s)
- Johannes Burtscher
- Department of Biomedical Sciences University of Lausanne Lausanne Switzerland
- Institute of Sport Sciences, University of Lausanne Lausanne Switzerland
| | - Muhammed Muazzam Kamil Syed
- Laboratory of Molecular and Chemical Biology of Neurodegeneration Brain Mind Institute, EPFL Lausanne Switzerland
| | - Hilal A. Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration Brain Mind Institute, EPFL Lausanne Switzerland
| | - Grégoire P. Millet
- Institute of Sport Sciences, University of Lausanne Lausanne Switzerland
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153
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Perim RR, El-Chami M, Gonzalez-Rothi EJ, Mitchell GS. Baseline Arterial CO 2 Pressure Regulates Acute Intermittent Hypoxia-Induced Phrenic Long-Term Facilitation in Rats. Front Physiol 2021; 12:573385. [PMID: 33716760 PMCID: PMC7943620 DOI: 10.3389/fphys.2021.573385] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/02/2021] [Indexed: 01/25/2023] Open
Abstract
Moderate acute intermittent hypoxia (mAIH) elicits a progressive increase in phrenic motor output lasting hours post-mAIH, a form of respiratory motor plasticity known as phrenic long-term facilitation (pLTF). mAIH-induced pLTF is initiated by activation of spinally-projecting raphe serotonergic neurons during hypoxia and subsequent serotonin release near phrenic motor neurons. Since raphe serotonergic neurons are also sensitive to pH and CO2, the prevailing arterial CO2 pressure (PaCO2) may modulate their activity (and serotonin release) during hypoxic episodes. Thus, we hypothesized that changes in background PaCO2 directly influence the magnitude of mAIH-induced pLTF. mAIH-induced pLTF was evaluated in anesthetized, vagotomized, paralyzed and ventilated rats, with end-tidal CO2 (i.e., a PaCO2 surrogate) maintained at: (1) ≤39 mmHg (hypocapnia); (2) ∼41 mmHg (normocapnia); or (3) ≥48 mmHg (hypercapnia) throughout experimental protocols. Although baseline phrenic nerve activity tended to be lower in hypocapnia, short-term hypoxic phrenic response, i.e., burst amplitude (Δ = 5.1 ± 1.1 μV) and frequency responses (Δ = 21 ± 4 bpm), was greater than in normocapnic (Δ = 3.6 ± 0.6 μV and 8 ± 4, respectively) or hypercapnic rats (Δ = 2.0 ± 0.6 μV and −2 ± 2, respectively), followed by a progressive increase in phrenic burst amplitude (i.e., pLTF) for at least 60 min post mAIH. pLTF in the hypocapnic group (Δ = 4.9 ± 0.6 μV) was significantly greater than in normocapnic (Δ = 2.8 ± 0.7 μV) or hypercapnic rats (Δ = 1.7 ± 0.4 μV). In contrast, although hypercapnic rats also exhibited significant pLTF, it was attenuated versus hypocapnic rats. When pLTF was expressed as percent change from maximal chemoreflex stimulation, all pairwise comparisons were found to be statistically significant (p < 0.05). We conclude that elevated PaCO2 undermines mAIH-induced pLTF in anesthetized rats. These findings contrast with well-documented effects of PaCO2 on ventilatory LTF in awake humans.
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Affiliation(s)
- Raphael R Perim
- Department of Physical Therapy, McKnight Brain Institute, Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL, United States
| | - Mohamed El-Chami
- Department of Physical Therapy, McKnight Brain Institute, Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL, United States
| | - Elisa J Gonzalez-Rothi
- Department of Physical Therapy, McKnight Brain Institute, Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL, United States
| | - Gordon S Mitchell
- Department of Physical Therapy, McKnight Brain Institute, Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL, United States
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154
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Nichols NL, Mitchell GS. Mechanisms of severe acute intermittent hypoxia-induced phrenic long-term facilitation. J Neurophysiol 2021; 125:1146-1156. [PMID: 33566744 DOI: 10.1152/jn.00691.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Moderate acute intermittent hypoxia (mAIH; 35-55 mmHg PaO2) elicits phrenic long-term facilitation (pLTF) by a mechanism that requires activation of Gq protein-coupled serotonin type 2 receptors, MEK/ERK MAP kinase, and NADPH oxidase activity and is constrained by cAMP-PKA signaling. In contrast, severe AIH (sAIH; 25-35 mmHg PaO2) elicits Gs protein-coupled adenosine type 2 A receptor-dependent pLTF. Another Gs protein-coupled receptor, serotonin 7 receptors, elicits phrenic motor facilitation (pMF) by a mechanism that requires exchange protein activated by cyclic AMP (EPAC) and phosphatidylinositol 3-kinase/Akt (PI3K/Akt) activation and is constrained by NADPH oxidase activity. Here, we tested the hypothesis that the same downstream signaling mechanisms giving rise to serotonin 7 (vs. serotonin 2) receptor-induced pMF underlie sAIH-induced pLTF. In anesthetized rats, sAIH-induced pLTF was compared after pretreatment with intrathecal (C4) injections of inhibitors for: 1) EPAC (ESI-05); 2) MEK/ERK (UO126); 3) PKA (KT-5720); 4) PI3K/Akt (PI828); and 5) NADPH oxidase (apocynin). In partial agreement with our hypothesis, sAIH-induced pLTF was abolished by ESI-05 and PI828 and marginally enhanced by apocynin but, surprisingly, was abolished by UO126 and attenuated by KT-5720. Mechanisms of sAIH-induced pLTF reflect elements of both Gq and Gs pathways to pMF, likely as a consequence of the complex, cross-talk interactions between them.NEW & NOTEWORTHY Distinct mechanisms give rise to pLTF induced by moderate and severe AIH. We demonstrate that, unlike moderate AIH, severe AIH-induced pLTF requires EPAC and PI3K/Akt and is marginally constrained by NADPH oxidase activity. Surprisingly, sAIH-induced pLTF requires MEK/ERK activity similar to moderate AIH-induced pLTF and is reduced by PKA inhibition. We suggest sAIH-induced pLTF arises from complex interactions between dominant mechanisms characteristic of moderate versus severe AIH-induced pLTF.
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Affiliation(s)
- Nicole L Nichols
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
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155
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Affiliation(s)
- Matiram Pun
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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156
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DeFrates KG, Franco D, Heber-Katz E, Messersmith PB. Unlocking mammalian regeneration through hypoxia inducible factor one alpha signaling. Biomaterials 2021; 269:120646. [PMID: 33493769 PMCID: PMC8279430 DOI: 10.1016/j.biomaterials.2020.120646] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/19/2020] [Accepted: 12/29/2020] [Indexed: 02/08/2023]
Abstract
Historically, the field of regenerative medicine has aimed to heal damaged tissue through the use of biomaterials scaffolds or delivery of foreign progenitor cells. Despite 30 years of research, however, translation and commercialization of these techniques has been limited. To enable mammalian regeneration, a more practical approach may instead be to develop therapies that evoke endogenous processes reminiscent of those seen in innate regenerators. Recently, investigations into tadpole tail regrowth, zebrafish limb restoration, and the super-healing Murphy Roths Large (MRL) mouse strain, have identified ancient oxygen-sensing pathways as a possible target to achieve this goal. Specifically, upregulation of the transcription factor, hypoxia-inducible factor one alpha (HIF-1α) has been shown to modulate cell metabolism and plasticity, as well as inflammation and tissue remodeling, possibly priming injuries for regeneration. Since HIF-1α signaling is conserved across species, environmental or pharmacological manipulation of oxygen-dependent pathways may elicit a regenerative response in non-healing mammals. In this review, we will explore the emerging role of HIF-1α in mammalian healing and regeneration, as well as attempts to modulate protein stability through hyperbaric oxygen treatment, intermittent hypoxia therapy, and pharmacological targeting. We believe that these therapies could breathe new life into the field of regenerative medicine.
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Affiliation(s)
- Kelsey G DeFrates
- Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Daniela Franco
- Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Ellen Heber-Katz
- Laboratory of Regenerative Medicine, Lankenau Institute for Medical Research, Wynnewood, PA, USA.
| | - Phillip B Messersmith
- Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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157
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Tadjalli A, Seven YB, Perim RR, Mitchell GS. Systemic inflammation suppresses spinal respiratory motor plasticity via mechanisms that require serine/threonine protein phosphatase activity. J Neuroinflammation 2021; 18:28. [PMID: 33468163 PMCID: PMC7816383 DOI: 10.1186/s12974-021-02074-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 01/05/2021] [Indexed: 01/05/2023] Open
Abstract
Background Inflammation undermines multiple forms of neuroplasticity. Although inflammation and its influence on plasticity in multiple neural systems has been extensively studied, its effects on plasticity of neural networks controlling vital life functions, such as breathing, are less understood. In this study, we investigated the signaling mechanisms whereby lipopolysaccharide (LPS)-induced systemic inflammation impairs plasticity within the phrenic motor system—a major spinal respiratory motor pool that drives contractions of the diaphragm muscle. Here, we tested the hypotheses that lipopolysaccharide-induced systemic inflammation (1) blocks phrenic motor plasticity by a mechanism that requires cervical spinal okadaic acid-sensitive serine/threonine protein phosphatase (PP) 1/2A activity and (2) prevents phosphorylation/activation of extracellular signal-regulated kinase 1/2 mitogen activated protein kinase (ERK1/2 MAPK)—a key enzyme necessary for the expression of phrenic motor plasticity. Methods To study phrenic motor plasticity, we utilized a well-characterized model for spinal respiratory plasticity called phrenic long-term facilitation (pLTF). pLTF is characterized by a long-lasting, progressive enhancement of inspiratory phrenic nerve motor drive following exposures to moderate acute intermittent hypoxia (mAIH). In anesthetized, vagotomized and mechanically ventilated adult Sprague Dawley rats, we examined the effect of inhibiting cervical spinal serine/threonine PP 1/2A activity on pLTF expression in sham-vehicle and LPS-treated rats. Using immunofluorescence optical density analysis, we compared mAIH-induced phosphorylation/activation of ERK 1/2 MAPK with and without LPS-induced inflammation in identified phrenic motor neurons. Results We confirmed that mAIH-induced pLTF is abolished 24 h following low-dose systemic LPS (100 μg/kg, i.p.). Cervical spinal delivery of the PP 1/2A inhibitor, okadaic acid, restored pLTF in LPS-treated rats. LPS also prevented mAIH-induced enhancement in phrenic motor neuron ERK1/2 MAPK phosphorylation. Thus, a likely target for the relevant okadaic acid-sensitive protein phosphatases is ERK1/2 MAPK or its upstream activators. Conclusions This study increases our understanding of fundamental mechanisms whereby inflammation disrupts neuroplasticity in a critical population of motor neurons necessary for breathing, and highlights key roles for serine/threonine protein phosphatases and ERK1/2 MAPK kinase in the plasticity of mammalian spinal respiratory motor circuits.
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Affiliation(s)
- Arash Tadjalli
- Breathing Research and Therapeutics Center, Department of Physical Therapy and The McKnight Brain Institute, College of Public Health & Health Professions, University of Florida, 1225 Center Drive, PO Box 100154, Gainesville, FL, 32610, USA
| | - Yasin B Seven
- Breathing Research and Therapeutics Center, Department of Physical Therapy and The McKnight Brain Institute, College of Public Health & Health Professions, University of Florida, 1225 Center Drive, PO Box 100154, Gainesville, FL, 32610, USA
| | - Raphael R Perim
- Breathing Research and Therapeutics Center, Department of Physical Therapy and The McKnight Brain Institute, College of Public Health & Health Professions, University of Florida, 1225 Center Drive, PO Box 100154, Gainesville, FL, 32610, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and The McKnight Brain Institute, College of Public Health & Health Professions, University of Florida, 1225 Center Drive, PO Box 100154, Gainesville, FL, 32610, USA.
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158
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Ciesla MC, Seven YB, Allen LL, Smith KN, Asa ZA, Simon AK, Holland AE, Santiago JV, Stefan K, Ross A, Gonzalez-Rothi EJ, Mitchell GS. Serotonergic innervation of respiratory motor nuclei after cervical spinal injury: Impact of intermittent hypoxia. Exp Neurol 2021; 338:113609. [PMID: 33460645 DOI: 10.1016/j.expneurol.2021.113609] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/31/2020] [Accepted: 01/09/2021] [Indexed: 12/12/2022]
Abstract
Although cervical spinal cord injury (cSCI) disrupts bulbo-spinal serotonergic projections, partial recovery of spinal serotonergic innervation below the injury site is observed after incomplete cSCI. Since serotonin contributes to functional recovery post-injury, treatments to restore or accelerate serotonergic reinnervation are of considerable interest. Intermittent hypoxia (IH) was reported to increase serotonin innervation near respiratory motor neurons in spinal intact rats, and to improve function after cSCI. Here, we tested the hypotheses that spontaneous serotonergic reinnervation of key respiratory (phrenic and intercostal) motor nuclei: 1) is partially restored 12 weeks post C2 hemisection (C2Hx); 2) is enhanced by IH; and 3) results from sprouting of spared crossed-spinal serotonergic projections below the site of injury. Serotonin was assessed via immunofluorescence in male Sprague Dawley rats with and without C2Hx (12 wks post-injury); individual groups were exposed to 28 days of: 1) normoxia; 2) daily acute IH (dAIH28: 10, 5 min 10.5% O2 episodes per day; 5 min normoxic intervals); 3) mild chronic IH (IH28-5/5: 5 min 10.5% O2 episodes; 5 min intervals; 8 h/day); or 4) moderate chronic IH (IH28-2/2: 2 min 10.5% O2 episodes; 2 min intervals; 8 h/day), simulating IH experienced during moderate sleep apnea. After C2Hx, the number of ipsilateral serotonergic structures was decreased in both motor nuclei, regardless of IH protocol. However, serotonergic structures were larger after C2Hx in both motor nuclei, and total serotonin immunolabeling area was increased in the phrenic motor nucleus but reduced in the intercostal motor nucleus. Both chronic IH protocols increased serotonin structure size and total area in the phrenic motor nuclei of uninjured rats, but had no detectable effects after C2Hx. Although the functional implications of fewer but larger serotonergic structures are unclear, we confirm that serotonergic reinnervation is substantial following injury, but IH does not affect the extent of reinnervation.
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Affiliation(s)
- Marissa C Ciesla
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Yasin B Seven
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Latoya L Allen
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Kristin N Smith
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Zachary A Asa
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Alec K Simon
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Ashley E Holland
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Juliet V Santiago
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Kelsey Stefan
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Ashley Ross
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Elisa J Gonzalez-Rothi
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, FL 32610, USA.
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159
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Millet GP, Debevec T, Brocherie F, Burtscher M, Burtscher J. Altitude and COVID-19: Friend or foe? A narrative review. Physiol Rep 2021; 8:e14615. [PMID: 33340275 PMCID: PMC7749581 DOI: 10.14814/phy2.14615] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/11/2022] Open
Abstract
Recent reports suggest that high-altitude residence may be beneficial in the novel coronavirus disease (COVID-19) implicating that traveling to high places or using hypoxic conditioning thus could be favorable as well. Physiological high-altitude characteristics and symptoms of altitude illnesses furthermore seem similar to several pathologies associated with COVID-19. As a consequence, high altitude and hypoxia research and related clinical practices are discussed for potential applications in COVID-19 prevention and treatment. We summarize the currently available evidence on the relationship between altitude/hypoxia conditions and COVID-19 epidemiology and pathophysiology. The potential for treatment strategies used for altitude illnesses is evaluated. Symptomatic overlaps in the pathophysiology of COVID-19 induced ARDS and high altitude illnesses (i.e., hypoxemia, dyspnea…) have been reported but are also common to other pathologies (i.e., heart failure, pulmonary embolism, COPD…). Most treatments of altitude illnesses have limited value and may even be detrimental in COVID-19. Some may be efficient, potentially the corticosteroid dexamethasone. Physiological adaptations to altitude/hypoxia can exert diverse effects, depending on the constitution of the target individual and the hypoxic dose. In healthy individuals, they may optimize oxygen supply and increase mitochondrial, antioxidant, and immune system function. It is highly debated if these physiological responses to hypoxia overlap in many instances with SARS-CoV-2 infection and may exert preventive effects under very specific conditions. The temporal overlap of SARS-CoV-2 infection and exposure to altitude/hypoxia may be detrimental. No evidence-based knowledge is presently available on whether and how altitude/hypoxia may prevent, treat or aggravate COVID-19. The reported lower incidence and mortality of COVID-19 in high-altitude places remain to be confirmed. High-altitude illnesses and COVID-19 pathologies exhibit clear pathophysiological differences. While potentially effective as a prophylactic measure, altitude/hypoxia is likely associated with elevated risks for patients with COVID-19. Altogether, the different points discussed in this review are of possibly some relevance for individuals who aim to reach high-altitude areas. However, due to the ever-changing state of understanding of COVID-19, all points discussed in this review may be out of date at the time of its publication.
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Affiliation(s)
| | - Tadej Debevec
- Faculty of SportUniversity of LjubljanaLjubljanaSlovenia
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160
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Mishra P, Jaseja H, Goyal M. A critical analysis of the purported role of hypoxaemia in the comorbidity of obstructive sleep apnoea and epilepsy. Clin Physiol Funct Imaging 2021; 41:4-9. [PMID: 33068455 DOI: 10.1111/cpf.12672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/30/2020] [Accepted: 10/13/2020] [Indexed: 02/05/2023]
Abstract
Obstructive sleep apnoea (OSA) is a globally prevalent sleep disorder of significant health concern and confounded with several comorbidities resulting in adverse effect(s) on quality of life in patients afflicted with it. Of particular interest is the enigmatic high comorbidity of OSA with epilepsy, the exact underlying pathophysiology of which remains elusive despite a multitude of research performed in the last four decades. Hypoxaemia, which is an important characteristic feature found in OSA during apnoeic spells, has been implicated in the high comorbidity of OSA with epilepsy, the basis of which rests upon hypoxaemia-mediated brain damage, subcortical release phenomenon, oxidative stress and neuroinflammatory reactions. However, several studies present contradictory evidences that potentially refute the hypoxaemia-based mechanism. Additionally, the role of hypercapnia thatgenerally accompanies hypoxaemia during apnoeic spells, cannot be overlooked and is known to be potentially protective against neuronal hyperexcitability. Thus, hypoxaemia theory implicated in the high comorbidity of OSA and epilepsy appears weak and refutable. This brief paper studies and critically analyses the role of hypoxaemia in conjunction with hypercapnia in the underlying pathophysiology of the comorbidity.
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Affiliation(s)
- Priyadarshini Mishra
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, India
| | | | - Manish Goyal
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, India
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161
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Camacho-Cardenosa M, Quesada-Gómez JM, Camacho-Cardenosa A, Leal A, Dorado G, Torrecillas-Baena B, Casado-Díaz A. Effects of normobaric cyclic hypoxia exposure on mesenchymal stem-cell differentiation-pilot study on bone parameters in elderly. World J Stem Cells 2020; 12:1667-1690. [PMID: 33505607 PMCID: PMC7789125 DOI: 10.4252/wjsc.v12.i12.1667] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/30/2020] [Accepted: 10/20/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Mesenchymal stem cells (MSC) of bone marrow are the progenitor of osteoblasts and adipocytes. MSC tend to differentiate into adipocytes, instead of osteoblasts, with aging. This favors the loss of bone mass and development of osteoporosis. Hypoxia induces hypoxia inducible factor 1α gene encoding transcription factor, which regulates the expression of genes related to energy metabolism and angiogenesis. That allows a better adaptation to low O2 conditions. Sustained hypoxia has negative effects on bone metabolism, favoring bone resorption. Yet, surprisingly, cyclic hypoxia (CH), short times of hypoxia followed by long times in normoxia, can modulate MSC differentiation and improve bone health in aging. AIM To evaluate the CH effect on MSC differentiation, and whether it improves bone mineral density in elderly. METHODS MSC cultures were induced to differentiate into osteoblasts or adipocytes, in CH (3% O2 for 1, 2 or 4 h, 4 d a week). Extracellular-matrix mineralization and lipid-droplet formation were studied in MSC induced to differentiate into osteoblast or adipocytes, respectively. In addition, gene expression of marker genes, for osteogenesis or adipogenesis, have been quantified by quantitative real time polymerase chain reaction. The in vivo studies with elderly (> 75 years old; n = 10) were carried out in a hypoxia chamber, simulating an altitude of 2500 m above sea level, or in normoxia, for 18 wk (36 CH sessions of 16 min each). Percentages of fat mass and bone mineral density from whole body, trunk and right proximal femur (femoral, femoral neck and trochanter) were assessed, using dual-energy X-ray absorptiometry. RESULTS CH (4 h of hypoxic exposure) inhibited extracellular matrix mineralization and lipid-droplet formation in MSC induced to differentiate into osteoblasts or adipocytes, respectively. However, both parameters were not significantly affected by the other shorter hypoxia times assessed. The longest periods of hypoxia downregulated the expression of genes related to extracellular matrix formation, in MSC induced to differentiate into osteoblasts. Interestingly, osteocalcin (associated to energy metabolism) was upregulated. Vascular endothelial growth factor an expression and low-density lipoprotein receptor related protein 5/6/dickkopf Wnt signaling pathway inhibitor 1 (associated to Wnt/β-catenin pathway activation) increased in osteoblasts. Yet, they decreased in adipocytes after CH treatments, mainly with the longest hypoxia times. However, the same CH treatments increased the osteoprotegerin/receptor activator for nuclear factor kappa B ligand ratio in both cell types. An increase in total bone mineral density was observed in elderly people exposed to CH, but not in specific regions. The percentage of fat did not vary between groups. CONCLUSION CH may have positive effects on bone health in the elderly, due to its possible inhibitory effect on bone resorption, by increasing the osteoprotegerin / receptor activator for nuclear factor kappa B ligand ratio.
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Affiliation(s)
| | - José Manuel Quesada-Gómez
- CIBER De Fragilidad Y Envejecimiento Saludable (CIBERFES), Unidad De Gestión Clínica De Endocrinología Y Nutrición, Instituto Maimónides De Investigación Biomédica De Córdoba, Hospital Universitario Reina Sofía, Córdoba 14004, Spain
| | | | - Alejo Leal
- Servicio de Traumatología, Hospital de Cáceres, Cáceres 10004, Spain
| | - Gabriel Dorado
- Departamento Bioquímica y Biología Molecular, Campus Rabanales C6-1-E17, Campus de Excelencia Internacional Agroalimentario (ceiA3), Universidad de Córdoba-CIBERFES, 14071 Córdoba, Spain
| | - Bárbara Torrecillas-Baena
- CIBER De Fragilidad Y Envejecimiento Saludable (CIBERFES), Unidad De Gestión Clínica De Endocrinología Y Nutrición, Instituto Maimónides De Investigación Biomédica De Córdoba, Hospital Universitario Reina Sofía, Córdoba 14004, Spain
| | - Antonio Casado-Díaz
- CIBER De Fragilidad Y Envejecimiento Saludable (CIBERFES), Unidad De Gestión Clínica De Endocrinología Y Nutrición, Instituto Maimónides De Investigación Biomédica De Córdoba, Hospital Universitario Reina Sofía, Córdoba 14004, Spain
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Wan N, Tang X, Ding H, Yan Y, Zhuang Y, Qi C, Chen Q, Xie W, Zhang J, Wang Y, Liang M, Ning W, Cao J. Influence of coexistence of mild OSA on airway mucus hypersecretion in patients with COPD. J Breath Res 2020; 15. [PMID: 33339013 DOI: 10.1088/1752-7163/abd52e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 12/17/2020] [Indexed: 11/11/2022]
Abstract
PURPOSE The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) can cause multiple system damage, and the main physiological mechanisms are continuous hypoxia and intermittent hypoxia (IH). Airway mucus hypersecretion is an important clinical feature of COPD, which can cause a progressive decline of lung function, acute COPD aggravation, and disease progression. The purpose of our study is to determine the influence of the coexistence of mild OSA on airway mucus hypersecretion. PATIENTS AND METHODS Clinical data and airway epithelial samples were collected. The average fluorescence intensity of MUC5AC and the number of goblet cells were measured through immunofluorescence staining. MUC5AC expression was measured in human bronchial epithelial (HBE) cells exposed to normoxia, IH, particulate matter (PM), and PM+IH using real-time quantitative polymerase chain reaction and western blotting. RESULTS FEV1% pred and FEV1/FVC were higher in patients with COPD-OSA overlap syndrome(OS) than in patients with COPD alone. Patients with OS had less sputum volume than patients with COPD alone.MUC5AC expression and the number of goblet cells in the airway epithelium in the COPD alone group were significantly higher than those in the OS groups. The PM+IH group had lower MUC5AC mRNA and protein expression in HBE cells than the PM group. CONCLUSIONS The coexistence of mild OSA may reduce goblet cell proliferation and MUC5AC expression in the airway epithelium of patients with COPD. Mild IH inhibited PM-induced up-regulation of MUC5AC expression in the mRNA and protein levels in HBE cells.
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Affiliation(s)
- Nansheng Wan
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Xin Tang
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, CHINA
| | - Hui Ding
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Yuxia Yan
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Yan Zhuang
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Chao Qi
- State Key Laboratory of Medicinal Chemical Biology, Nankai University College of Life Sciences, Tianjin, Tianjin, CHINA
| | - Qianqian Chen
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Wei Xie
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Jing Zhang
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Yan Wang
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Maoli Liang
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, CHINA
| | - Wen Ning
- State Key Laboratory of Medicinal Chemical Biology, Nankai University College of Life Sciences, Tianjin, Tianjin, CHINA
| | - Jie Cao
- Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, CHINA
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163
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Hobbins L, Girard O, Gaoua N, Hunter S. Acute psycho-physiological responses to perceptually regulated hypoxic and normoxic interval walks in overweight-to-obese adults. J Sci Med Sport 2020; 24:481-487. [PMID: 33281095 DOI: 10.1016/j.jsams.2020.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/02/2020] [Accepted: 11/16/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVES We investigated psycho-physiological responses to perceptually regulated interval walks in hypoxia versus normoxia in obese individuals. DESIGN Within-participants repeated measures. METHODS Ten obese adults (BMI=32±3kg/m-2) completed a 60-min interval session (15×2min walking at a rating of perceived exertion of 14 on the 6-20 Borg scale with 2min of rest) either in hypoxia (FiO2=13.0%, HYP) or normoxia (NOR). A third trial replicating the HYP speed pattern was carried out in normoxia as a control (CON). Exercise responses were analysed comparing the average of 1st to 3rd exercise bouts to those of the 4th-6th, 7th-9th, 10th-12th and 13th-15th exercise bouts (block 1 versus 2, 3, 4 and 5). RESULTS Treadmill speed was slower during block 4 (6.14±0.67 versus 6.24±0.73km/h-1) and block 5 (6.12±0.64 versus 6.25±0.75km/h-1) in HYP compared to NOR or CON (p=0.009). Compared to NOR and CON, heart rate was +6-10% higher (p=0.001), whilst arterial oxygen saturation (-12-13%) was lower (p<0.001) in HYP. Perceived limb discomfort was lower in HYP and CON versus NOR (-21±4% and -34±6%; p=0.004). CONCLUSIONS In overweight-to-obese adults, perceptually regulated interval walks in hypoxia versus normoxia leads to progressively slower speeds along with lower limb discomfort and larger physiological stress than normoxia. Walking at the speed adopted in hypoxia produces similar psycho-physiological responses at the same absolute intensity in normoxia.
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Affiliation(s)
- Liam Hobbins
- Sport and Exercise Science Research Centre (SESRC), London South Bank University, United Kingdom
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Australia.
| | - Nadia Gaoua
- Sport and Exercise Science Research Centre (SESRC), London South Bank University, United Kingdom
| | - Steve Hunter
- Sport and Exercise Science Research Centre (SESRC), London South Bank University, United Kingdom
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164
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Soo J, Girard O, Ihsan M, Fairchild T. The Use of the SpO 2 to FiO 2 Ratio to Individualize the Hypoxic Dose in Sport Science, Exercise, and Health Settings. Front Physiol 2020; 11:570472. [PMID: 33329021 PMCID: PMC7714921 DOI: 10.3389/fphys.2020.570472] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/09/2020] [Indexed: 01/15/2023] Open
Affiliation(s)
- Jacky Soo
- Murdoch Applied Sports Science Laboratory, Discipline of Exercise Science, Murdoch University, Perth, WA, Australia
| | - Olivier Girard
- School of Human Sciences, Exercise and Sport Science, The University of Western Australia, Perth, WA, Australia
| | - Mohammed Ihsan
- Research and Scientific Support, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
- Human Potential and Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Timothy Fairchild
- Murdoch Applied Sports Science Laboratory, Discipline of Exercise Science, Murdoch University, Perth, WA, Australia
- The Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Perth, WA, Australia
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165
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Brito J, Siques P, Pena E. Long-term chronic intermittent hypoxia: a particular form of chronic high-altitude pulmonary hypertension. Pulm Circ 2020; 10:5-12. [PMID: 33110494 PMCID: PMC7557688 DOI: 10.1177/2045894020934625] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022] Open
Abstract
In some subjects, high-altitude hypobaric hypoxia leads to high-altitude pulmonary
hypertension. The threshold for the diagnosis of high-altitude pulmonary hypertension is a
mean pulmonary artery pressure of 30 mmHg, even though for general pulmonary hypertension
is ≥25 mmHg. High-altitude pulmonary hypertension has been associated with high hematocrit
findings (chronic mountain sickness), and although these are two separate entities, they
have a synergistic effect that should be considered. In recent years, a new condition
associated with high altitude was described in South America named long-term chronic
intermittent hypoxia and has appeared in individuals who commute to work at high altitude
but live and rest at sea level. In this review, we discuss the initial epidemiological
pattern from the early studies done in Chile, the clinical presentation and possible
molecular mechanism and a discussion of the potential management of this condition.
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Affiliation(s)
- Julio Brito
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
| | - Patricia Siques
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
| | - Eduardo Pena
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
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CARDIORESPIRATORY SYSTEM AND ANTIHYPOXIC RESISTANCE STATE IN ELDER CORONARY HEART DISEASE PATIENTS. EUREKA: HEALTH SCIENCES 2020. [DOI: 10.21303/2504-5679.2020.001418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of the study. Evaluation of cardiorespiratory system and microcirculation state in elder CHD patients with different resistance against hypoxia.
Methods. The author has carried out a retrospective analysis of 103 CHD 60+-patients, their deaths have occurred due to cardiovascular events. Two patient groups have been formed including patients (68 persons) having kept their resistance to hypoxia (their blood SO2 level was never below 80 %) and patients (35 ones) with decreased resistance to hypoxia, their blood SO2 level having been dropped below 80 %.
Results: The life span of patients with decreased hypoxia resistance is lower comparing to ones having kept such resistance. The patients with decreased hypoxia resistance demonstrate decreased ejection fraction, increased mass of left ventricle myocardium as well as increased left ventricle volumes. Such patients show also significant increase of mean daily values of systolic, diastolic, and mean arterial pressure. Generally, the micro-circulation state in patients with decreased anti-hypoxic resistance is lower comparing to persons having kept this resistance. Simultaneously, the endothelial function of persons with decreased anti-hypoxic resistance is significantly worse. The pulmonary ventilation system patency and bronchial patency in these persons are also lowered comparing to these indices in patients with kept anti-hypoxic resistance.
Conclusions: The decrease of anti-hypoxic resistance leads to the shorter life span on elderly CHD patients. Such decreased resistance is accompanied by worsened potency of cardio-respiratory system, microcirculation, and endothelial system functioning.
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Glazachev OS, Geppe NA, Timofeev YS, Samartseva VG, Dudnik EN, Zapara MA, Chebysheva SN. Indicators of individual hypoxia resistance — a way to optimize hypoxic training for children. ROSSIYSKIY VESTNIK PERINATOLOGII I PEDIATRII (RUSSIAN BULLETIN OF PERINATOLOGY AND PEDIATRICS) 2020. [DOI: 10.21508/1027-4065-2020-65-4-78-84] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- O. S. Glazachev
- Sechenov First Moscow State Medical University (Sechenov University)
| | - N. A. Geppe
- Sechenov First Moscow State Medical University (Sechenov University)
| | - Yu. S. Timofeev
- Sechenov First Moscow State Medical University (Sechenov University)
| | - V. G. Samartseva
- Sechenov First Moscow State Medical University (Sechenov University)
| | - E. N. Dudnik
- Sechenov First Moscow State Medical University (Sechenov University)
| | - M. A. Zapara
- Sechenov First Moscow State Medical University (Sechenov University)
| | - S. N. Chebysheva
- Sechenov First Moscow State Medical University (Sechenov University)
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168
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Hu K, Deng W, Yang J, Wei Y, Wen C, Li X, Chen Q, Ke D, Li G. Intermittent hypoxia reduces infarct size in rats with acute myocardial infarction: a systematic review and meta-analysis. BMC Cardiovasc Disord 2020; 20:422. [PMID: 32962654 PMCID: PMC7507284 DOI: 10.1186/s12872-020-01702-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 09/09/2020] [Indexed: 11/20/2022] Open
Abstract
Background To determine whether intermittent hypoxia (IH) can reduce the infarct size (IS) after acute myocardial infarction (AMI) in rats. Methods Articles were identified in PubMed, EMBASE and the Web of Science and were included if they evaluated the effect of IH on the changes in the infarcted area after AMI in rats. Results A preliminary search identified 3633 articles and 29 data sets from 23 articles (12 in vivo, 16 in vitro). The IS decreased after AMI in IH rats both in vitro (SMD -1.46, 95% CI [− 2.37, − 0.55]; I2 = 85.6%, P = 0.000) and in vivo (SMD -1.43, 95% CI [− 2.05, − 0.82], I2 = 73.6%, P = 0.000). Sensitivity analysis indicated that IH had a strong protective effect against myocardial infarction, and the hypoxia concentration was significantly correlated with the change in IS after AMI. Conclusion IH can reduce IS after AMI in rats. This effect of IH may be related to the dose of hypoxia, and the oxygen concentration may be one of the most important influencing factors.
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Affiliation(s)
- Ke Hu
- Department of Nephrology, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Wei Deng
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China.
| | - Jing Yang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Yu Wei
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Chaolin Wen
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Xingsheng Li
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Qingwei Chen
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Dazhi Ke
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Guiqiong Li
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
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169
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Simpkins AN, Busl KM, Amorim E, Barnett-Tapia C, Cervenka MC, Dhakar MB, Etherton MR, Fung C, Griggs R, Holloway RG, Kelly AG, Khan IR, Lizarraga KJ, Madagan HG, Onweni CL, Mestre H, Rabinstein AA, Rubinos C, Dionisio-Santos DA, Youn TS, Merck LH, Maciel CB. Proceedings from the Neurotherapeutics Symposium on Neurological Emergencies: Shaping the Future of Neurocritical Care. Neurocrit Care 2020; 33:636-645. [PMID: 32959201 PMCID: PMC7736003 DOI: 10.1007/s12028-020-01085-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
Effective treatment options for patients with life-threatening neurological disorders are limited. To address this unmet need, high-impact translational research is essential for the advancement and development of novel therapeutic approaches in neurocritical care. "The Neurotherapeutics Symposium 2019-Neurological Emergencies" conference, held in Rochester, New York, in June 2019, was designed to accelerate translation of neurocritical care research via transdisciplinary team science and diversity enhancement. Diversity excellence in the neuroscience workforce brings innovative and creative perspectives, and team science broadens the scientific approach by incorporating views from multiple stakeholders. Both are essential components needed to address complex scientific questions. Under represented minorities and women were involved in the organization of the conference and accounted for 30-40% of speakers, moderators, and attendees. Participants represented a diverse group of stakeholders committed to translational research. Topics discussed at the conference included acute ischemic and hemorrhagic strokes, neurogenic respiratory dysregulation, seizures and status epilepticus, brain telemetry, neuroprognostication, disorders of consciousness, and multimodal monitoring. In these proceedings, we summarize the topics covered at the conference and suggest the groundwork for future high-yield research in neurologic emergencies.
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Affiliation(s)
- Alexis N Simpkins
- Department of Neurology, McKnight Brain Institute, University of Florida College of Medicine, Room L3-100, 1149 Newell Drive, Gainesville, FL, 32611, USA.
| | - Katharina M Busl
- Department of Neurology, McKnight Brain Institute, University of Florida College of Medicine, Room L3-100, 1149 Newell Drive, Gainesville, FL, 32611, USA
- Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - Edilberto Amorim
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Carolina Barnett-Tapia
- Ellen and Martin Prosserman Centre for Neuromuscular Disorders, Toronto General Hospital, Toronto, ON, Canada
| | - Mackenzie C Cervenka
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Monica B Dhakar
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Mark R Etherton
- J. Phillip Kistler Stroke Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Celia Fung
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Robert Griggs
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Robert G Holloway
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Adam G Kelly
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Imad R Khan
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Karlo J Lizarraga
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Hannah G Madagan
- Department of Neurology, McKnight Brain Institute, University of Florida College of Medicine, Room L3-100, 1149 Newell Drive, Gainesville, FL, 32611, USA
| | - Chidinma L Onweni
- Department of Critical Care Medicine, Mayo Clinic, Jacksonville, FL, USA
| | - Humberto Mestre
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, USA
| | | | - Clio Rubinos
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | | | - Teddy S Youn
- Department of Neurology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Lisa H Merck
- Department of Emergency Medicine, University of Florida College of Medicine, Gainesville, FL, USA
- Department of Health Outcomes and Biomedical Informatics, University of Florida College of Medicine, Gainesville, FL, USA
| | - Carolina B Maciel
- Department of Neurology, McKnight Brain Institute, University of Florida College of Medicine, Room L3-100, 1149 Newell Drive, Gainesville, FL, 32611, USA
- Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
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170
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Villasana-Salazar B, Hernández-Soto R, Guerrero-Gómez ME, Ordaz B, Manrique-Maldonado G, Salgado-Puga K, Peña-Ortega F. Chronic intermittent hypoxia transiently increases hippocampal network activity in the gamma frequency band and 4-Aminopyridine-induced hyperexcitability in vitro. Epilepsy Res 2020; 166:106375. [PMID: 32745888 DOI: 10.1016/j.eplepsyres.2020.106375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/21/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022]
Abstract
Chronic intermittent hypoxia (CIH) is the most distinct feature of obstructive sleep apnea (OSA), a common breathing and sleep disorder that leads to several neuropathological consequences, including alterations in the hippocampal network and in seizure susceptibility. However, it is currently unknown whether these alterations are permanent or remit upon normal oxygenation. Here, we investigated the effects of CIH on hippocampal spontaneous network activity and hyperexcitability in vitro and explored whether these alterations endure or fade after normal oxygenation. Results showed that applying CIH for 21 days to adult rats increases gamma-band hippocampal network activity and aggravates 4-Aminopyridine-induced epileptiform activity in vitro. Interestingly, these CIH-induced alterations remit after 30 days of normal oxygenation. Our findings indicate that hippocampal network alterations and increased seizure susceptibility induced by CIH are not permanent and can be spontaneously reverted, suggesting that therapeutic interventions against OSA in patients with epilepsy, such as surgery or continuous positive airway pressure (CPAP), could be favorable for seizure control.
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Affiliation(s)
- Benjamín Villasana-Salazar
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México
| | - Rebeca Hernández-Soto
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México
| | - María Estefanía Guerrero-Gómez
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México
| | - Benito Ordaz
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México
| | - Guadalupe Manrique-Maldonado
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México
| | - Karla Salgado-Puga
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México.
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171
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Chacaroun S, Borowik A, Doutreleau S, Belaidi E, Wuyam B, Tamisier R, Pépin JL, Flore P, Verges S. Cardiovascular and metabolic responses to passive hypoxic conditioning in overweight and mildly obese individuals. Am J Physiol Regul Integr Comp Physiol 2020; 319:R211-R222. [PMID: 32609532 DOI: 10.1152/ajpregu.00311.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although severe intermittent hypoxia (IH) is well known to induce deleterious cardiometabolic consequences, moderate IH may induce positive effects in obese individuals. The present study aimed to evaluate the effect of two hypoxic conditioning programs on cardiovascular and metabolic health status of overweight or obese individuals. In this randomized single-blind controlled study, 35 subjects (54 ± 9.3 yr, 31.7 ± 3.5 kg/m2) were randomized into three 8-wk interventions (three 1-h sessions per week): sustained hypoxia (SH), arterial oxygen saturation ([Formula: see text]) = 75%; IH, 5 min [Formula: see text] = 75% - 3 min normoxia; normoxia. Ventilation, heart rate, blood pressure, and tissue oxygenation were measured during the first and last hypoxic conditioning sessions. Vascular function, blood glucose and insulin, lipid profile, nitric oxide metabolites, and oxidative stress were evaluated before and after the interventions. Both SH and IH increased ventilation in hypoxia (+1.8 ± 2.1 and +2.3 ± 3.6 L/min, respectively; P < 0.05) and reduced normoxic diastolic blood pressure (-12 ± 15 and -13 ± 10 mmHg, respectively; P < 0.05), whereas changes in normoxic systolic blood pressure were not significant (+3 ± 9 and -6 ± 13 mmHg, respectively; P > 0.05). IH only reduced heart rate variability (e.g., root-mean-square difference of successive normal R-R intervals in normoxia -21 ± 35%; P < 0.05). Both SH and IH induced no significant change in body mass index, vascular function, blood glucose, insulin and lipid profile, nitric oxide metabolites, or oxidative stress, except for an increase in superoxide dismutase activity following SH. This study indicates that passive hypoxic conditioning in obese individuals induces some positive cardiovascular and respiratory improvements despite no change in anthropometric data and even a reduction in heart rate variability during IH exposure.
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Affiliation(s)
- Samarmar Chacaroun
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Anna Borowik
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Stephane Doutreleau
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Elise Belaidi
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Bernard Wuyam
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Renaud Tamisier
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Jean-Louis Pépin
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Patrice Flore
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Samuel Verges
- HP2 laboratory, Univiversité Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
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172
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Tan AQ, Barth S, Trumbower RD. Acute intermittent hypoxia as a potential adjuvant to improve walking following spinal cord injury: evidence, challenges, and future directions. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2020; 8:188-198. [PMID: 33738145 DOI: 10.1007/s40141-020-00270-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Purpose of Review The reacquisition and preservation of walking ability are highly valued goals in spinal cord injury (SCI) rehabilitation. Recurrent episodes of breathing low oxygen (i.e., acute intermittent hypoxia, AIH) is a potential therapy to promote walking recovery after incomplete SCI via endogenous mechanisms of neuroplasticity. Here, we report on the progress of AIH, alone or paired with other treatments, on walking recovery in persons with incomplete SCI. We evaluate the evidence of AIH as a therapy ready for clinical and home use and the real and perceived challenges that may interfere with this possibility. Recent Findings Repetitive AIH is a safe and an efficacious treatment to enhance strength, walking speed and endurance, as well as, dynamic balance in persons with chronic, incomplete SCI. Summary The potential for AIH as a treatment for SCI remains high, but further research is necessary to understand treatment targets and effectiveness in a large cohort of persons with SCI.
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Affiliation(s)
- Andrew Quesada Tan
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA. USA
- Spaulding Rehabilitation Hospital, Boston MA
| | - Stella Barth
- Spaulding Rehabilitation Hospital, Boston MA
- Harvard University, Cambridge MA
| | - Randy D Trumbower
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA. USA
- Spaulding Rehabilitation Hospital, Boston MA
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173
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Törpel A, Peter B, Schega L. Effect of Resistance Training Under Normobaric Hypoxia on Physical Performance, Hematological Parameters, and Body Composition in Young and Older People. Front Physiol 2020; 11:335. [PMID: 32411007 PMCID: PMC7198789 DOI: 10.3389/fphys.2020.00335] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/23/2020] [Indexed: 12/22/2022] Open
Abstract
Background Resistance training (RT) under hypoxic conditions has been used to increase muscular performance under normoxic conditions in young people. However, the effects of RT and thus of RT under hypoxia (RTH) could also be valuable for parameters of physical capacity and body composition across the lifespan. Therefore, we compared the effects of low- to moderate-load RTH with matched designed RT on muscular strength capacity, cardiopulmonary capacity, hematological adaptation, and body composition in young and older people. Methods In a pre–post randomized, blinded, and controlled experiment, 42 young (18 to 30 year) and 42 older (60 to 75 year) participants were randomly assigned to RTH or RT (RTH young, RT young, RTH old, RT old). Both groups performed eight resistance exercises (25–40% of 1RM, 3 × 15 repetitions) four times a week over 5 weeks. The intensity of hypoxic air for the RTH was administered individually in regards to the oxygen saturation of the blood (SpO2): ∼80–85%. Changes and differences in maximal isokinetic strength, cardiopulmonary capacity, total hemoglobin mass (tHb), blood volume (BV), fat free mass (FFM), and fat mass (FM) were determined pre–post, and the acute reaction of erythropoietin (EPO) was tested during the intervention. Results In all parameters, no significant pre–post differences in mean changes (time × group effects p = 0.120 to 1.000) were found between RTH and RT within the age groups. However, within the four groups, isolated significant improvements (p < 0.050) of the single groups were observed regarding the muscular strength of the legs and the cardiopulmonary capacity. Discussion Although the hypoxic dose and the exercise variables of the resistance training in this study were based on the current recommendations of RTH, the RTH design used had no superior effect on the tested parameters in young and older people in comparison to the matched designed RT under normoxia after a 5-week intervention period. Based on previous RTH-studies as well as the knowledge about RT in general, it can be assumed that the expected higher effects of RTH can may be achieved by changing exercise variables (e.g., longer intervention period, higher loads).
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Affiliation(s)
- Alexander Törpel
- Department Health and Physical Activity, Institute III Sport Science, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Beate Peter
- Department Health and Physical Activity, Institute III Sport Science, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Lutz Schega
- Department Health and Physical Activity, Institute III Sport Science, Otto von Guericke University Magdeburg, Magdeburg, Germany
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174
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Gangwar A, Paul S, Ahmad Y, Bhargava K. Intermittent hypoxia modulates redox homeostasis, lipid metabolism associated inflammatory processes and redox post-translational modifications: Benefits at high altitude. Sci Rep 2020; 10:7899. [PMID: 32404929 PMCID: PMC7220935 DOI: 10.1038/s41598-020-64848-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 04/09/2020] [Indexed: 01/27/2023] Open
Abstract
Intermittent hypoxia, initially associated with adverse effects of sleep apnea, has now metamorphosed into a module for improved sports performance. The regimen followed for improved sports performance is milder intermittent hypoxic training (IHT) as compared to chronic and severe intermittent hypoxia observed in sleep apnea. Although several studies have indicated the mechanism and enough data on physiological parameters altered by IH is available, proteome perturbations remain largely unknown. Altitude induced hypobaric hypoxia is known to require acclimatization as it causes systemic redox stress and inflammation in humans. In the present study, a short IHT regimen consisting of previously reported physiologically beneficial FIO2 levels of 13.5% and 12% was administered to human subjects. These subjects were then airlifted to altitude of 3500 m and their plasma proteome along with associated redox parameters were analyzed on days 4 and 7 of high altitude stay. We observed that redox stress and associated post-translational modifications, perturbed lipid metabolism and inflammatory signaling were induced by IHT exposure at Baseline. However, this caused activation of antioxidants, energy homeostasis mechanisms and anti-inflammatory responses during subsequent high-altitude exposure. Thus, we propose IHT as a beneficial non-pharmacological intervention that benefits individuals venturing to high altitude areas.
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Affiliation(s)
- Anamika Gangwar
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Subhojit Paul
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Yasmin Ahmad
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi, 110054, India.
| | - Kalpana Bhargava
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi, 110054, India.
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175
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Ding H, Huang J, Wu D, Zhao J, Huang J, Lin Q. Silencing of the long non-coding RNA MEG3 suppresses the apoptosis of aortic endothelial cells in mice with chronic intermittent hypoxia via downregulation of HIF-1α by competitively binding to microRNA-135a. J Thorac Dis 2020; 12:1903-1916. [PMID: 32642094 PMCID: PMC7330306 DOI: 10.21037/jtd-19-2472] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Background Chronic intermittent hypoxia (CIH) involves substantial cortico-hippocampal injury, causing impairments of neurocognitive, respiratory, and cardiovascular functions. Long non-coding RNAs (lncRNAs) participate in CIH functions and development. Therefore, we explored the mechanisms involving lncRNA maternally expressed gene 3 (MEG3) regulating the aortic endothelial function of CIH mice via regulation of microRNA-135a (miR-135a) and the hypoxia-inducible factor (HIF)-1α. Methods Expression of MEG3, miR-135a, and HIF-1α in CIH mice and CIH-treated cells was detected. Then, the apoptosis and proliferation of the aortic endothelial cells were examined to verify whether miR-135a and HIF-1α participated in CIH. Next, the interactions between MEG3, miR-135a, and HIF-1α were explored. Later, the effects of MEG3/miR-135a/HIF-1α on the expression of proliferation- and apoptosis-related factors and aortic injury were investigated via gain- and loss-of function studies both in vivo and in vitro. Results MEG3 and HIF-1α were highly expressed while miR-135a was poorly expressed in CIH mice and CIH-modeled cells. Moreover, miR-135a targeted HIF-1α to promote cell proliferation and inhibit apoptosis. MEG3 regulated HIF-1α expression by competitively binding to miR-135a. More importantly, we found that the silencing of MEG3/HIF-1α and the overexpression of miR-135a inhibited the apoptosis and injury of aortic endothelial cells while promoting cell proliferation in CIH mice. Conclusions Altogether, silencing of MEG3 suppressed the aortic endothelial injury and cell apoptosis in CIH mice by downregulating HIF-1α through sponging miR-135a, providing evidence of a potential therapeutic target for CIH.
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Affiliation(s)
- Haibo Ding
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
| | - Jiefeng Huang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
| | - Dawen Wu
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
| | - Jianming Zhao
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
| | - Jianchai Huang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
| | - Qichang Lin
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
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176
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Wollman LB, Streeter KA, Fuller DD. Ampakine pretreatment enables a single brief hypoxic episode to evoke phrenic motor facilitation. J Neurophysiol 2020; 123:993-1003. [PMID: 31940229 PMCID: PMC7099472 DOI: 10.1152/jn.00708.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Phrenic long-term facilitation (LTF) is a sustained increase in phrenic motor output occurring after exposure to multiple (but not single) hypoxic episodes. Ampakines are a class of drugs that enhance AMPA receptor function. Ampakines can enhance expression of neuroplasticity, and the phrenic motor system is fundamentally dependent on excitatory glutamatergic currents. Accordingly, we tested the hypothesis that combining ampakine pretreatment with a single brief hypoxic exposure would result in phrenic motor facilitation lasting well beyond the period of hypoxia. Phrenic nerve output was recorded in urethane-anesthetized, ventilated, and vagotomized adult Sprague-Dawley rats. Ampakine CX717 (15 mg/kg iv; n = 8) produced a small increase in phrenic inspiratory burst amplitude and frequency, but values quickly returned to predrug baseline. When CX717 was followed 2 min later by a 5-min exposure to hypoxia (n = 8; PaO2 ~45 mmHg), a persistent increase in phrenic inspiratory burst amplitude (i.e., phrenic motor facilitation) was observed up to 60 min posthypoxia (103 ± 53% increase from baseline). In contrast, when hypoxia was preceded by vehicle injection (10% 2-hydroxypropyl-β-cyclodextrin; n = 8), inspiratory phrenic bursting was similar to baseline values at 60 min. Additional experiments with another ampakine (CX1739, 15 mg/kg) produced comparable results. We conclude that pairing low-dose ampakine treatment with a single brief hypoxic exposure can evoke sustained phrenic motor facilitation. This targeted approach for enhancing respiratory neuroplasticity may have value in the context of hypoxia-based neurorehabilitation strategies.NEW & NOTEWORTHY A single brief episode of hypoxia (e.g., 3-5 min) does not evoke long-lasting increases in respiratory motor output after the hypoxia is concluded. Ampakines are a class of drugs that enhance AMPA receptor function. We show that pairing low-dose ampakine treatment with a single brief hypoxic exposure can evoke sustained phrenic motor facilitation after the acute hypoxic episode.
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Affiliation(s)
- L B Wollman
- Department of Physical Therapy, University of Florida, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida
| | - K A Streeter
- Department of Physical Therapy, University of Florida, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida
| | - D D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida
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177
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Susta D, Glazachev OS, Zapara MA, Dudnik EN, Samartseva VG. Redox Homeostasis in Humans Exposed to Intermittent Hypoxia-Normoxia and to Intermittent Hypoxia-Hyperoxia. High Alt Med Biol 2020; 21:45-51. [PMID: 32096667 DOI: 10.1089/ham.2019.0059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Aim: Exposure to hypoxia is known to increase oxidative stress and to impair antioxidant defenses in humans. The aim of the study was to measure oxidative stress and antioxidant capacity in healthy humans after being acutely exposed to both intermittent hypoxia-normoxia (IHN) and intermittent hypoxia-hyperoxia (IHH). Methods: Twenty-one healthy, young male participants were exposed to both IHN and IHH (fraction of inspired oxygen [FIO2] 0.11 for up to 7 minutes followed by 3-5 minutes of exposure to normoxia (room air) or hyperoxia, FIO2 0.3-0.35) in a crossover design study. In each participant, oxidative stress and antioxidant capacity were measured before and after each exposure in both experimental conditions. Results: After IHN, compared with baseline, neither oxidative stress (289.1 ± 63.2 vs. 262.2 ± 85.2 UCarr) nor antioxidant capacity (2376.1 ± 452.9 vs. 2525.0 ± 400.7 UCor) was significantly different. After IHH, neither oxidative stress (285.1 ± 94.2 vs. 277.5 ± 86.7 UCarr) nor antioxidant capacity (2653.6 ± 492.7 vs. 2568.4 ± 427.4 UCor) was significantly different compared with baseline. When the two studied exposure modalities were compared, there was no significant difference between groups with respect to both oxidative stress and antioxidant capacity. Conclusions: These data suggest that exposing healthy individuals to short-term IHN and IHH does not increase oxidative stress and it does not impair antioxidant defenses.
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Affiliation(s)
- Davide Susta
- Physiology Department, IM Sechenov Medical University, Moscow, Russia.,School of Health and Human Performance, Dublin City University, Dublin, Ireland
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178
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Tobin B, Costalat G, Renshaw GMC. Intermittent not continuous hypoxia provoked haematological adaptations in healthy seniors: hypoxic pattern may hold the key. Eur J Appl Physiol 2020; 120:707-718. [DOI: 10.1007/s00421-020-04310-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/27/2020] [Indexed: 02/04/2023]
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179
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Mindukshev IV, Sudnitsyna JS, Skverchinskaya EA, Andreyeva AY, Dobrylko IA, Senchenkova EY, Krivchenko AI, Gambaryan SP. Erythrocytes’ Reactions to Osmotic, Ammonium, and Oxidative Stress Are Inhibited under Hypoxia. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2020. [DOI: 10.1134/s1990747819040081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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180
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Beyeler SA, Hodges MR, Huxtable AG. Impact of inflammation on developing respiratory control networks: rhythm generation, chemoreception and plasticity. Respir Physiol Neurobiol 2020; 274:103357. [PMID: 31899353 DOI: 10.1016/j.resp.2019.103357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/17/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
The respiratory control network in the central nervous system undergoes critical developmental events early in life to ensure adequate breathing at birth. There are at least three "critical windows" in development of respiratory control networks: 1) in utero, 2) newborn (postnatal day 0-4 in rodents), and 3) neonatal (P10-13 in rodents, 2-4 months in humans). During these critical windows, developmental processes required for normal maturation of the respiratory control network occur, thereby increasing vulnerability of the network to insults, such as inflammation. Early life inflammation (induced by LPS, chronic intermittent hypoxia, sustained hypoxia, or neonatal maternal separation) acutely impairs respiratory rhythm generation, chemoreception and increases neonatal risk of mortality. These early life impairments are also greater in young males, suggesting sex-specific impairments in respiratory control. Further, neonatal inflammation has a lasting impact on respiratory control by impairing adult respiratory plasticity. This review focuses on how inflammation alters respiratory rhythm generation, chemoreception and plasticity during each of the three critical windows. We also highlight the need for additional mechanistic studies and increased investigation into how glia (such as microglia and astrocytes) play a role in impaired respiratory control after inflammation. Understanding how inflammation during critical windows of development disrupt respiratory control networks is essential for developing better treatments for vulnerable neonates and preventing adult ventilatory control disorders.
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Affiliation(s)
- Sarah A Beyeler
- Department of Human Physiology, University of Oregon, Eugene, OR, 97403, United States
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - Adrianne G Huxtable
- Department of Human Physiology, University of Oregon, Eugene, OR, 97403, United States.
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181
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Song K, Zhang Y, Ga Q, Bai Z, Ge RL. Increased Insulin Sensitivity by High-Altitude Hypoxia in Mice with High-Fat Diet-Induced Obesity Is Associated with Activated AMPK Signaling and Subsequently Enhanced Mitochondrial Biogenesis in Skeletal Muscles. Obes Facts 2020; 13:455-472. [PMID: 32966981 PMCID: PMC7670386 DOI: 10.1159/000508112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 04/20/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND This study aimed to investigate whether and how high altitude-associated ambient hypoxia affects insulin sensitivity in mice fed a high-fat diet (HFD). METHODS Mice were randomly divided into a control group (with normal diet feeding and low-altitude housing), LA/HFD group (with HFD feeding and low-altitude housing), and HA/HFD group (with HFD feeding and high-altitude housing). RESULTS After 8 weeks, mice in the HA/HFD group showed improved insulin sensitivity-related indices compared with the LA/HFD group. In mice residing in a low-altitude region, HFD significantly impaired mitochondrial respiratory function and mitochondrial DNA content in skeletal muscles, which was partially reversed in mice in the HA/HFD group. In addition, the fatty acid oxidation-related enzyme gene CPT1 (carnitine palmitoyltransferase 1) and genes related to mitochondrial biogenesis such as peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1), and mitochondrial transcription factor A (Tfam) were upregulated in the skeletal muscles of mice housed at high altitude, in comparison to in the LA/HFD group. Furthermore, AMPK (adenosine monophosphate-activated protein kinase) signaling was activated in the skeletal muscles, as evidenced by a higher expression of phosphorylated AMPK (p-AMPK) and protein kinase B (p-AKT) in the HA/HFD group than in the LA/HFD group. CONCLUSION Our study suggests that high-altitude hypoxia improves insulin sensitivity in mice fed an HFD, which is associated with AMPK activation in the skeletal muscle and consequently enhanced mitochondrial biogenesis and fatty acid oxidation. This work provides a molecular explanation for why high altitude is associated with a reduced incidence of insulin resistance in the obese population.
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Affiliation(s)
- Kang Song
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China,
- Key Laboratory for Application of High Altitude Medicine in Qinghai Province, Xining, China,
- Department of Endocrinology, Qinghai Provincial People's Hospital, Xining, China,
| | - Yifan Zhang
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
- Key Laboratory for Application of High Altitude Medicine in Qinghai Province, Xining, China
| | - Qin Ga
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
- Key Laboratory for Application of High Altitude Medicine in Qinghai Province, Xining, China
| | - Zhenzhong Bai
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
- Key Laboratory for Application of High Altitude Medicine in Qinghai Province, Xining, China
| | - Ri-Li Ge
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
- Key Laboratory for Application of High Altitude Medicine in Qinghai Province, Xining, China
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182
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Wang H, Shi X, Schenck H, Hall JR, Ross SE, Kline GP, Chen S, Mallet RT, Chen P. Intermittent Hypoxia Training for Treating Mild Cognitive Impairment: A Pilot Study. Am J Alzheimers Dis Other Demen 2020; 35:1533317519896725. [PMID: 31902230 PMCID: PMC10624018 DOI: 10.1177/1533317519896725] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although intermittent hypoxia training (IHT) has proven effective against various clinical disorders, its impact on mild cognitive impairment (MCI) is unknown. This pilot study examined IHT's safety and therapeutic efficacy in elderly patients with amnestic MCI (aMCI). Seven patients with aMCI (age 69 ± 3 years) alternately breathed 10% O2 and room-air, each 5 minutes, for 8 cycles/session, 3 sessions/wk for 8 weeks. The patients' resting arterial pressures fell by 5 to 7 mm Hg (P < .05) and cerebral tissue oxygenation increased (P < .05) following IHT. Intermittent hypoxia training enhanced hypoxemia-induced cerebral vasodilation (P < .05) and improved mini-mental state examination and digit span scores from 25.7 ± 0.4 to 27.7 ± 0.6 (P = .038) and from 24.7 ± 1.2 to 26.1 ± 1.3 (P = .047), respectively. California verbal learning test score tended to increase (P = .102), but trail making test-B and controlled oral word association test scores were unchanged. Adaptation to moderate IHT may enhance cerebral oxygenation and hypoxia-induced cerebrovasodilation while improving short-term memory and attention in elderly patients with aMCI.
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Affiliation(s)
- Hong Wang
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Xiangrong Shi
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Hannah Schenck
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - James R. Hall
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Sarah E. Ross
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
- Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Geoffrey P. Kline
- Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Shande Chen
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Robert T. Mallet
- Departments of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Peijie Chen
- Shanghai University of Sport, Shanghai, China
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183
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Intermittent Hypoxia Alleviates β-Aminopropionitrile Monofumarate Induced Thoracic Aortic Dissection in C57BL/6 Mice. Eur J Vasc Endovasc Surg 2019; 59:1000-1010. [PMID: 31879145 DOI: 10.1016/j.ejvs.2019.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 09/26/2019] [Accepted: 10/18/2019] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Thoracic aortic dissection (TAD) has a high mortality rate. Intermittent hypoxia (IH) triggers both harmful and beneficial effects in numerous physiological systems. The effects of IH on TAD development were explored in a mouse model. METHODS β-Aminopropionitrile monofumarate (BAPN) was used to induce TAD in C57BL/6 mice. Three week old male mice were treated with 1 g/kg/day BAPN in drinking water for four weeks and simultaneously subjected to IH (n = 30) (21%-5% O2, 90 s/cycle, 10 h/day, IH + BAPN group) or normoxia (n = 30) (21% O2, 24 h/day, BAPN group). Human VSMCs (HUASMCs) exposed to IH (30 min, 5% O2)/re-oxygenation (30 min, 21% O2) cycles with a maximum of 60 min/cycle to detect the effect of IH on HIF-1α and LOX via HIF-1α-siRNA. RESULTS It was found that BAPN administration significantly increased the lumen size and wall thickness of aortas compared with the normal group, but was significantly reversed by IH exposure. Additionally, IH exposure significantly increased the survival rate of BAPN induced TAD (70% vs. 40%). Furthermore, IH exposure reduced BAPN induced elastin breaks and apoptosis of vascular smooth muscle cells. IH exposure also reversed BAPN induced upregulation of inflammation and extracellular matrix (ECM) degradation. Real time polymerase chain reaction (RT-PCR) confirmed that IH inhibited inflammation and ECM degradation related genes interleukin (IL)-1β, IL-6, cathepsin S (Cat S), and matrix metalloproteinase 9 (MMP-9), but upregulated the ECM synthesis related genes lysyl oxidase (LOX) and collagen type I alpha2 (Col1a2) compared with the BAPN group. In vitro results suggest that IH promotes the expression of LOX via HIF-1α. CONCLUSION The results suggest that IH alleviates BAPN induced TAD in C57BL/6 mice.
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184
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Hypoxia induces a time- and tissue-specific response that elicits intertissue circadian clock misalignment. Proc Natl Acad Sci U S A 2019; 117:779-786. [PMID: 31848250 DOI: 10.1073/pnas.1914112117] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The occurrence and sequelae of disorders that lead to hypoxic spells such as asthma, chronic obstructive pulmonary disease, and obstructive sleep apnea (OSA) exhibit daily variance. This prompted us to examine the interaction between the hypoxic response and the circadian clock in vivo. We found that the global transcriptional response to acute hypoxia is tissue-specific and time-of-day-dependent. In particular, clock components differentially responded at the transcriptional and posttranscriptional level, and these responses depended on an intact circadian clock. Importantly, exposure to hypoxia phase-shifted clocks in a tissue-dependent manner led to intertissue circadian clock misalignment. This differential response relied on the intrinsic properties of each tissue and could be recapitulated ex vivo. Notably, circadian misalignment was also elicited by intermittent hypoxia, a widely used model for OSA. Given that phase coherence between circadian clocks is considered favorable, we propose that hypoxia leads to circadian misalignment, contributing to the pathophysiology of OSA and potentially other diseases that involve hypoxia.
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185
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Serebrovska TV, Grib ON, Portnichenko VI, Serebrovska ZO, Egorov E, Shatylo VB. Intermittent Hypoxia/Hyperoxia Versus Intermittent Hypoxia/Normoxia: Comparative Study in Prediabetes. High Alt Med Biol 2019; 20:383-391. [DOI: 10.1089/ham.2019.0053] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
| | - Oksana N. Grib
- D.F. Chebotarev State Institute of Gerontology, Kiev, Ukraine
| | | | | | - Egor Egorov
- CellAir Construction GmbH, Stuttgart, Germany
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Piotrowicz Z, Chalimoniuk M, Płoszczyca K K, Czuba M, Langfort J. Acute normobaric hypoxia does not affect the simultaneous exercise-induced increase in circulating BDNF and GDNF in young healthy men: A feasibility study. PLoS One 2019; 14:e0224207. [PMID: 31644554 PMCID: PMC6808427 DOI: 10.1371/journal.pone.0224207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 10/08/2019] [Indexed: 01/25/2023] Open
Abstract
Physical exercise has a neuromodulatory effect on the central nervous system (CNS) partially by modifying expression of neuropeptides produced and secreted by neurons and glial cells, among which the best examined are brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). Because both neurotrophins can cross the brain-blood barrier (BBB), their blood levels indirectly reflect their production in the CNS. Moreover, both neuropeptides are involved in modulation of dopaminergic and serotoninergic system function. Because limited information is available on the effects of exercise to volition exhaustion and acute hypoxia on CNS, BDNF and GDNF formation, the aims of the present study were to verify whether 1) acute exercise to exhaustion in addition to neurons also activates glial cells and 2) additional exposure to acute normobaric moderate hypoxia affects their function. In this feasibility study we measured blood concentrations of BDNF, GDNF, and neuropeptides considered as biomarkers of brain damage (bFGF, NGF, S100B, GFAP) in seven sedentary healthy young men who performed a graded exercise test to volitional exhaustion on a cycle ergometer under normoxic (N) and hypoxic conditions: 2,000 m (H2; FiO2 = 16.6%) and 3,000 m altitude (H3; FiO2 = 14.7%). In all conditions serum concentrations of both BDNF and GDNF increased immediately after cessation of exercise (p<0.01). There was no effect of condition or interaction (condition x time of measurement) and exercise on any of the brain damage biomarkers: bFGF, NGF, S100B, GFAP. Moreover, in N (0<0.01) and H3 (p<0.05) exercise caused elevated serum 5-HT concentration. The results suggest that a graded effort to volitional exhaustion in normoxia, as well as hypoxia, simultaneously activates both neurons and astrocytes. Considering that s100B, GFAP, bFGF, and NGF (produced mainly by astrocytes) are markers of brain damage, it can be assumed that a maximum effort in both conditions is safe for the CNS.
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Affiliation(s)
- Zofia Piotrowicz
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Małgorzata Chalimoniuk
- Department of Tourism and Health in Biała Podlaska, The Józef Piłsudski University of Physical Education, Warsaw, Poland
| | | | - Miłosz Czuba
- Department of Kinesiology, Institute of Sport, Warsaw, Poland
- Department of Sports Theory, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Józef Langfort
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
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187
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Ge MQ, Yeung SC, Mak JCW, Ip MSM. Differential metabolic and inflammatory responses to intermittent hypoxia in substrains of lean and obese C57BL/6 mice. Life Sci 2019; 238:116959. [PMID: 31628916 DOI: 10.1016/j.lfs.2019.116959] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 12/22/2022]
Abstract
AIMS This study was to investigate the degree of susceptibility to intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), between the two mice inbred lines C57BL/6N (6N) and C57BL/6J (6J). MATERIALS AND METHODS Four-week old male mice of 6N and 6J substrains (n = 8) were randomized to standard diet (SD) group or high fat (HF) diet group. At the age of 13-week, all two groups of mice were subjected to either air or IH (IH30; thirty hypoxic events per hour) for one week. KEY FINDINGS All mice fed with HF diet exhibited obesity with more body weight and fat mass (percentage to body weight) gain. IH reduced serum LDL, HDL and total cholesterol levels in lean 6J mice. In obese mice, IH lowered obesity-induced serum total cholesterol level in 6J substrain but raised further in 6N substrain. Furthermore, IH caused elevation of serum FFA and MDA levels, and pro-inflammatory cytokines MCP-1 and IL-6 levels in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) of lean 6J but not lean 6N mice. There was reduced number of adipocytes and elevation of macrophages in SAT and VAT of HF-induced obese mice of both substrains. IH led to increased number of adipocytes and macrophages in SAT of lean 6J mice. SIGNIFICANCE The genetic difference between 6N and 6J mice may have direct impact on metabolic and inflammatory responses after IH. Therefore, attention must be given for the selection of C57BL mice substrains in the experimental IH-exposed mouse model.
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Affiliation(s)
- Meng Qin Ge
- Departments of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Sze Chun Yeung
- Departments of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Judith Choi Wo Mak
- Departments of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China; Pharmacology & Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China.
| | - Mary Sau Man Ip
- Departments of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China.
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188
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Mateika JH. A reminder that experimentally induced intermittent hypoxia is an incomplete model of obstructive sleep apnea and its outcome measures. J Appl Physiol (1985) 2019; 127:1620-1621. [PMID: 31600097 DOI: 10.1152/japplphysiol.00549.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Jason H Mateika
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan.,John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan.,Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan
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189
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Hobbins L, Girard O, Gaoua N, Hunter S. Acute Psychophysiological Responses to Cyclic Variation of Intermittent Hypoxic Exposure in Adults with Obesity. High Alt Med Biol 2019; 20:262-270. [DOI: 10.1089/ham.2019.0002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Liam Hobbins
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Olivier Girard
- Murdoch Applied Sports Science (MASS) Laboratory, School of Psychology and Exercise Science, Murdoch University, Perth, Australia
| | - Nadia Gaoua
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Steve Hunter
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
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190
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Abstract
Intermittent hypoxemia (IH) events are common during early postnatal life, particularly in preterm infants. These events have been associated with multiple morbidities, including retinopathy of prematurity, sleep disordered breathing, neurodevelopmental impairment, and mortality. The relationship between IH and poor outcomes may depend on the patterns (frequency, duration, and timing) of the IH events. Current treatment modalities used in the clinical setting have been only partially successful in reducing the incidence of apnea and accompanying IH, but the risks and benefits of more aggressive interventions should include knowledge of the relationship between IH and morbidity.
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Affiliation(s)
- Juliann M. Di Fiore
- Case Western Reserve University, Rainbow Babies & Children’s Hospital, Division of Neonatology, Suite RBC 3100, Cleveland, OH 44106-6010
| | - Peter M MacFarlane
- Case Western Reserve University, Rainbow Babies & Children's Hospital, 11100 Euclid Avenue, Suite RBC 3100, Cleveland, OH 44106-6010, USA
| | - Richard J Martin
- Case Western Reserve University, Rainbow Babies & Children's Hospital, 11100 Euclid Avenue, Suite RBC 3100, Cleveland, OH 44106-6010, USA
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191
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Camacho-Cardenosa M, Camacho-Cardenosa A, Burtscher M, Brazo-Sayavera J, Tomas-Carus P, Olcina G, Timón R. Effects of Whole-Body Vibration Training Combined With Cyclic Hypoxia on Bone Mineral Density in Elderly People. Front Physiol 2019; 10:1122. [PMID: 31543827 PMCID: PMC6728928 DOI: 10.3389/fphys.2019.01122] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/13/2019] [Indexed: 12/13/2022] Open
Abstract
Prevention and treatment of osteoporosis are an issue of great concern in public health so that the increase/maintenance of whole-body bone mineral density (BMD) is clinically relevant and could reduce the financial burden. Whole-body vibration (WBV) has been recently proposed as a potential alternative to bone stimulation, which combined with therapies, could provide a new treatment for osteoporosis prevention. In this sense, moderate cyclic hypoxia protocols may help to restrain osteoclastic activity and/or stimulate osteoblastic activity, enhance the effects of whole-body vibration alone. So, the present study investigated the effects of cyclic hypoxic exposure combined with WBV training on BMD of the elderly. Healthy elderly persons (n = 30) were randomly assigned to a (1) Hypoxia-Whole Body Vibration group (HWBV; n = 10), (2) Normoxic-Whole Body Vibration group (NWBV; n = 10) or (3) Control group (CON; n = 10). During 18 weeks, HWBV performed WBV treatment under normobaric hypoxic conditions (16.1% FiO2). A vibration session included 4 bouts of 30 s (12.6 Hz–4 mm) with 1 min rest between bouts. NWBV performed the same vibration treatment as HWBV but under normoxic conditions. Whole-body and proximal femur BMD (g⋅cm−2) were measured using dual-energy X-ray absorptiometry. Two-way ANOVA indicated a borderline significant (p = 0.07) time x group interaction for total BMD; post hoc analysis revealed a slight but significant (p = 0.021) increase of BMD after treatment in the HWBV group. In conclusion, 18-week WBV training with hypoxic stimuli has shown positive effects for the participants of the current study. As changes did not differ significantly between groups, future large-scale studies will be necessary to confirm these findings.
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Affiliation(s)
| | | | - Martin Burtscher
- Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria
| | - Javier Brazo-Sayavera
- Instituto Superior de Educación Física, Universidad de la República, Rivera, Uruguay.,Polo de Desarrollo Universitario EFISAL, Universidad de la República, Rivera, Uruguay
| | - Pablo Tomas-Carus
- Departamento de Desporto e Saúde, Escola de Ciências e Tecnologia, Universidade de Évora, Évora, Portugal.,Comprehensive Health Research Centre (CHRC), Universidade de Évora, Évora, Portugal
| | - Guillermo Olcina
- Faculty of Sport Sciences, University of Extremadura, Cáceres, Spain
| | - Rafael Timón
- Faculty of Sport Sciences, University of Extremadura, Cáceres, Spain
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192
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Bergholt NL, Olesen ML, Foldager CB. Age-Dependent Systemic Effects of a Systemic Intermittent Hypoxic Therapy In Vivo. High Alt Med Biol 2019; 20:221-230. [PMID: 31260338 DOI: 10.1089/ham.2018.0113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Introduction: The adaptive response to systemic intermittent hypoxic therapy (SIHT) may be used for therapeutic advances due to the activation of multiple pathways involved in angiogenesis, immunomodulation, and tissue homeostasis. The aim of this study was to investigate the early age-dependent systemic response of different exposures of SIHT in mice. Materials and Methods: Sixty-four C57BL/6NRj female mice in three different age groups, young (4-5 weeks), adolescent (8-10 weeks), and adults (23-32 weeks), were exposed to SIHT. Different algorithms for equal hypoxic challenges (oxygen-decrease*time) were investigated to allow examination of the role of absolute hypoxia (oxygen-decrease) compared with relative hypoxia (total oxygen depletion over time). The systemic effects of angiogenetic regulation were investigated using blood samples analyzed by ELISA, proteome profiles, and proximity extension immunoassay. One-way analysis of variance with post hoc Bonferroni analyses was performed. Results: The early systemic response to SIHT was dependent on the absolute hypoxia rather than relative hypoxia over time. Serum erythropoietin (EPO) levels were increased significantly in young mice receiving low-oxygen SIHT treatments (10% and 15% oxygen). The expression of angiogenic proteins differed between the different age groups indicating an age-dependent response to SIHT. Focusing on hypoxia-inducible factor-1 (HIF-1) signaling, there was a trend toward upregulated angiogenetic response with younger age. Furthermore, clustering of protein expression in low-oxygen SIHT algorithms were found between young and adolescent mice. In adult mice, the majority of the proteins were downregulated as a response to SIHT. The systemic response of metabolites expressions was most pronounced in young mice. Systemic levels of cardiac troponin I (Tnni3) was unaffected by SIHT independent of age groups. Conclusions: The systemic response to SIHT is dependent on the absolute hypoxic exposure rather than the relative hypoxic depletion over time. Age-dependent effects of a short-term SIHT were associated with an increase in EPO, upregulation of angiogenetic pathways, and select metabolic and cell-surface proteins.
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Affiliation(s)
- Natasja Leth Bergholt
- Orthopaedic Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Morten Lykke Olesen
- Orthopaedic Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Casper Bindzus Foldager
- Orthopaedic Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Orthopaedics, Aarhus University Hospital, Aarhus, Denmark
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193
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Camacho-Hernández NP, Lorea-Hernández JJ, Peña-Ortega F. Microglial modulators reduce respiratory rhythm long-term facilitation in vitro. Respir Physiol Neurobiol 2019; 265:9-18. [DOI: 10.1016/j.resp.2018.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 06/08/2018] [Accepted: 07/30/2018] [Indexed: 12/28/2022]
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194
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Dutta B, Huang J, To J, Tam JP. LIR Motif-Containing Hyperdisulfide β-Ginkgotide is Cytoprotective, Adaptogenic, and Scaffold-Ready. Molecules 2019; 24:E2417. [PMID: 31262066 PMCID: PMC6651024 DOI: 10.3390/molecules24132417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/24/2022] Open
Abstract
Grafting a bioactive peptide onto a disulfide-rich scaffold is a promising approach to improve its structure and metabolic stability. The ginkgo plant-derived β-ginkgotide β-gB1 is a highly unusual molecule: Small, hyperdisulfide, and found only in selected ancient plants. It also contains a conserved 16-amino-acid core with three interlocking disulfides, as well as a six-amino-acid inter-cysteine loop 2 suitable for grafting peptide epitopes. However, very little is known about this recently-discovered family of molecules. Here, we report the biophysical and functional characterizations of the β-ginkgotide β-gB1 from G. biloba. A circular dichroism spectroscopy analysis at 90 °C and proteolytic treatments of β-gB1 supported that it is hyperstable. Data mining revealed that the β-gB1 loop 2 contains the canonical LC3 interacting region (LIR) motif crucial for selective autophagy. Cell-based assays and pull-down experiments showed that β-gB1 is an adaptogen, able to maintain cellular homeostasis through induced autophagosomes formation and to protect cells by targeting intracellular proteins from stress-mediated damage against hypoxia and the hypoxia-reoxygenation of induced cell death. This is the first report of an LIR-containing peptide natural product. Together, our results suggest that the plant-derived β-ginkgotide is cytoprotective, capable of targeting intracellular proteins, and holds promise as a hyperdisulfide scaffold for engineering peptidyl therapeutics with enhanced structural and metabolic stability.
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Affiliation(s)
- Bamaprasad Dutta
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Jiayi Huang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Janet To
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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195
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Abstract
Central sleep apnea is prevalent in patients with heart failure, healthy individuals at high altitudes, and chronic opiate users and in the initiation of “mixed” (that is, central plus obstructive apneas). This brief review focuses on (a) the causes of repetitive, cyclical central apneas as mediated primarily through enhanced sensitivities in the respiratory control system and (b) treatment of central sleep apnea through modification of key components of neurochemical control as opposed to the current universal use of positive airway pressure.
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Affiliation(s)
- Jerome A Dempsey
- Department of Population Health Sciences, University of Wisconsin - Madison, WARF Building, 7th Floor, 614 Walnut Street, Madison, WI 53726, USA
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196
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Tadjalli A, Mitchell GS. Cervical spinal 5-HT 2A and 5-HT 2B receptors are both necessary for moderate acute intermittent hypoxia-induced phrenic long-term facilitation. J Appl Physiol (1985) 2019; 127:432-443. [PMID: 31219768 DOI: 10.1152/japplphysiol.01113.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Serotonin (5-HT) is a key regulator of spinal respiratory motor plasticity. For example, spinal 5-HT receptor activation is necessary for the induction of phrenic long-term facilitation (pLTF), a form of respiratory motor plasticity triggered by moderate acute intermittent hypoxia (mAIH). mAIH-induced pLTF is blocked by cervical spinal application of the broad-spectrum 5-HT-receptor antagonist, methysergide. However, methysergide does not allow distinctions between the relative contributions of different 5-HT receptor subtypes. Intravenous administration of the Gq protein-coupled 5-HT2A/2C receptor antagonist ketanserin blocks mAIH-induced pLTF when administered before, but not after, mAIH; thus, 5-HT2 receptor activation is necessary for the induction but not maintenance of mAIH-induced pLTF. However, systemic ketanserin administration does not identify the site of the relevant 5-HT2A/2C receptors. Furthermore, this approach does not differentiate between the roles of 5-HT2A versus 5-HT2C receptors, nor does it preclude involvement of other Gq protein-coupled metabotropic 5-HT receptors capable of eliciting long-lasting phrenic motor facilitation, such as 5-HT2B receptors. Here we tested the hypothesis that mAIH-induced pLTF requires cervical spinal 5-HT2 receptor activation and determined which 5-HT2 receptor subtypes are involved. Anesthetized, paralyzed, and ventilated adult male Sprague Dawley rats were pretreated intrathecally with cervical (~C3-C5) spinal injections of subtype selective 5-HT2A/2C, 5-HT2B, or 5-HT2C receptor antagonists before mAIH. Whereas cervical spinal 5-HT2C receptor inhibition had no impact on mAIH-induced pLTF, pLTF was no longer observed after pretreatment with either 5-HT2A/2C or 5-HT2B receptor antagonists. Furthermore, spinal pretreatment with an MEK/ERK MAPK inhibitor blocked phrenic motor facilitation elicited by intrathecal injections of 5-HT2A but not 5-HT2B receptor agonists. Thus, mAIH-induced pLTF requires concurrent cervical spinal activation of both 5-HT2A and 5-HT2B receptors. However, these distinct receptor subtypes contribute to phrenic motor facilitation via distinct downstream signaling cascades that differ in their requirement for ERK MAPK signaling. The demonstration that both 5-HT2A and 5-HT2B receptors make unique contributions to mAIH-induced pLTF advances our understanding of mechanisms that underlie 5-HT-induced phrenic motor plasticity.NEW & NOTEWORTHY Moderate acute intermittent hypoxia (mAIH) triggers a persistent enhancement in phrenic motor output, an effect termed phrenic long-term facilitation (pLTF). mAIH-induced pLTF is blocked by cervical spinal application of the broad-spectrum serotonin (5-HT) receptor antagonist methysergide, demonstrating the need for spinal 5-HT receptor activation. However, the exact type of 5-HT receptors required for initiation of pLTF remains unknown. To the best of out knowledge, the present study is the first to demonstrate that 1) spinal coactivation of two distinct Gq protein-coupled 5-HT2 receptor subtypes is necessary for mAIH-induced pLTF, and 2) these receptors contribute to pLTF via cascades that differ in their requirement for ERK MAPK signaling.
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Affiliation(s)
- Arash Tadjalli
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and the McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Gordon S Mitchell
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and the McKnight Brain Institute, University of Florida, Gainesville, Florida
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197
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Chang JC, Lien CF, Lee WS, Chang HR, Hsu YC, Luo YP, Jeng JR, Hsieh JC, Yang KT. Intermittent Hypoxia Prevents Myocardial Mitochondrial Ca 2+ Overload and Cell Death during Ischemia/Reperfusion: The Role of Reactive Oxygen Species. Cells 2019; 8:cells8060564. [PMID: 31181855 PMCID: PMC6627395 DOI: 10.3390/cells8060564] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/01/2019] [Accepted: 06/05/2019] [Indexed: 12/24/2022] Open
Abstract
It has been documented that reactive oxygen species (ROS) contribute to oxidative stress, leading to diseases such as ischemic heart disease. Recently, increasing evidence has indicated that short-term intermittent hypoxia (IH), similar to ischemia preconditioning, could yield cardioprotection. However, the underlying mechanism for the IH-induced cardioprotective effect remains unclear. The aim of this study was to determine whether IH exposure can enhance antioxidant capacity, which contributes to cardioprotection against oxidative stress and ischemia/reperfusion (I/R) injury in cardiomyocytes. Primary rat neonatal cardiomyocytes were cultured in IH condition with an oscillating O2 concentration between 20% and 5% every 30 min. An MTT assay was conducted to examine the cell viability. Annexin V-FITC and SYTOX green fluorescent intensity and caspase 3 activity were detected to analyze the cell death. Fluorescent images for DCFDA, Fura-2, Rhod-2, and TMRM were acquired to analyze the ROS, cytosol Ca2+, mitochondrial Ca2+, and mitochondrial membrane potential, respectively. RT-PCR, immunocytofluorescence staining, and antioxidant activity assay were conducted to detect the expression of antioxidant enzymes. Our results show that IH induced slight increases of O2−· and protected cardiomyocytes against H2O2- and I/R-induced cell death. Moreover, H2O2-induced Ca2+ imbalance and mitochondrial membrane depolarization were attenuated by IH, which also reduced the I/R-induced Ca2+ overload. Furthermore, treatment with IH increased the expression of Cu/Zn SOD and Mn SOD, the total antioxidant capacity, and the activity of catalase. Blockade of the IH-increased ROS production abolished the protective effects of IH on the Ca2+ homeostasis and antioxidant defense capacity. Taken together, our findings suggest that IH protected the cardiomyocytes against H2O2- and I/R-induced oxidative stress and cell death through maintaining Ca2+ homeostasis as well as the mitochondrial membrane potential, and upregulation of antioxidant enzymes.
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Affiliation(s)
- Jui-Chih Chang
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
| | - Chih-Feng Lien
- Institute of Medical Sciences, Tzu Chi University, Hualien 97004, Taiwan.
| | - Wen-Sen Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
| | - Huai-Ren Chang
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Yu-Cheng Hsu
- Master Program in Medical Physiology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
| | - Yu-Po Luo
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Jing-Ren Jeng
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Jen-Che Hsieh
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Kun-Ta Yang
- Department of Physiology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
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198
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Camacho-Cardenosa M, Camacho-Cardenosa A, Timón R, Olcina G, Tomas-Carus P, Brazo-Sayavera J. Can Hypoxic Conditioning Improve Bone Metabolism? A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16101799. [PMID: 31117194 PMCID: PMC6572511 DOI: 10.3390/ijerph16101799] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 12/17/2022]
Abstract
Among other functions, hypoxia-inducible factor plays a critical role in bone–vascular coupling and bone formation. Studies have suggested that hypoxic conditioning could be a potential nonpharmacological strategy for treating skeletal diseases. However, there is no clear consensus regarding the bone metabolism response to hypoxia. Therefore, this review aims to examine the impact of different modes of hypoxia conditioning on bone metabolism. The PubMed and Web of Science databases were searched for experimental studies written in English that investigated the effects of modification of ambient oxygen on bone remodelling parameters of healthy organisms. Thirty-nine studies analysed the effect of sustained or cyclic hypoxia exposure on genetic and protein expression and mineralisation capacity of different cell models; three studies carried out in animal models implemented sustained or cyclic hypoxia; ten studies examined the effect of sustained, intermittent or cyclic hypoxia on bone health and hormonal responses in humans. Different modes of hypoxic conditioning may have different impacts on bone metabolism both in vivo and in vitro. Additional research is necessary to establish the optimal cyclical dose of oxygen concentration and exposure time.
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Affiliation(s)
| | | | - Rafael Timón
- Faculty of Sport Science, University of Extremadura, 10003 Cáceres, Spain.
| | - Guillermo Olcina
- Faculty of Sport Science, University of Extremadura, 10003 Cáceres, Spain.
| | - Pablo Tomas-Carus
- Departamento de Desporto e Saúde, Escola de Ciência e Tecnologia, Universidade de Évora, 7000-812 Évora, Portugal.
- Comprehensive Health Research Centre (CHRC), University of Évora, 7000-812 Évora, Portugal.
| | - Javier Brazo-Sayavera
- Instituto Superior de Educación Física, Universidad de la República, 40000 Rivera, Uruguay.
- Polo de Desarrollo Universitario EFISAL, Universidad de la República, 40000 Rivera, Uruguay.
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199
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Intermittent hypoxemia and oxidative stress in preterm infants. Respir Physiol Neurobiol 2019; 266:121-129. [PMID: 31100375 DOI: 10.1016/j.resp.2019.05.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/17/2019] [Accepted: 05/10/2019] [Indexed: 01/11/2023]
Abstract
Intermittent hypoxemia events (IH) are common in extremely preterm infants and are associated with many poor outcomes including retinopathy or prematurity, wheezing, bronchopulmonary dysplasia, cognitive or language delays and motor impairment. More recent data in animal and rodent models have suggested that specific patterns of IH may increase the risk for morbidity. The pathway by which these high risk patterns of IH initiate a pathological cascade is unknown but animal models suggest that oxidative stress may play a role. This review describes early postnatal patterns of IH in preterm infants, their relationship with morbidity, oxidative stress biomarkers relevant to the newborn infant and the relationship between IH and reactive oxygen species.
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Camacho-Cardenosa M, Camacho-Cardenosa A, Brazo-Sayavera J, Olcina G, Tomas-Carus P, Timón R. Evaluation of 18-Week Whole-Body Vibration Training in Normobaric Hypoxia on Lower Extremity Muscle Strength in an Elderly Population. High Alt Med Biol 2019; 20:157-164. [PMID: 31021265 DOI: 10.1089/ham.2018.0129] [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: 12/25/2022] Open
Abstract
Therapeutic benefits of hypoxic training have been suggested for clinical populations, such as elderly who could suffer loss of lower limb muscle strength and higher risk of falling. This study investigated the effects of 18 weeks of whole-body vibration (WBV) training in normobaric hypoxia on the strength parameters of an elderly population. Thirty-one healthy elderly participants were randomly assigned to a hypoxic whole-body vibration group (HWBV; n = 10), normoxic whole-body vibration group (NWBV; n = 11), or control group (n = 10). The experimental groups received the same vibration treatment in a hypoxia chamber (HWBV: 16.1% fraction of inspired oxygen [FiO2]; NWBV: 21.0% FiO2). Isokinetic leg muscle strength was evaluated using a Biodex System-3 isokinetic dynamometer. Body composition was obtained with dual-energy X-ray absorptiometry. There were no significant differences between groups in either strength or body composition parameters. The NWBV group showed statistically significant improvements in the maximal strength of knee extensors, with a small effect size (p = 0.004; d = 0.54). No significant differences were found in any variable of the HWBV group. The combination of WBV training and exposure to normobaric cyclic hypoxia carried out in the present study did not have an effect on strength parameters in healthy elderly subjects.
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Affiliation(s)
| | | | - Javier Brazo-Sayavera
- 2 Instituto Superior de Educación Física, Universidad de la República, Rivera, Uruguay.,3 Polo de Desarrollo Universitario EFISAL, Rivera, Uruguay
| | - Guillermo Olcina
- 1 Faculty of Sport Science, University of Extremadura, Caceres, Spain
| | - Pablo Tomas-Carus
- 4 Departamento de Desporto e Saúde, Escola de Cie^ncia e Tecnologia, Universidade de Évora, Évora, Portugal.,5 Comprehensive Health Research Centre (CHRC), University of Évora, Évora, Portugal
| | - Rafael Timón
- 1 Faculty of Sport Science, University of Extremadura, Caceres, Spain
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