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acute intermittent hypoxia

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https://www.readbyqxmd.com/read/29021191/enhancement-of-phrenic-long-term-facilitation-following-repetitive-acute-intermittent-hypoxia-is-blocked-by-the-glycolytic-inhibitor-2-deoxyglucose
#1
Peter M MacFarlane, Stephane Vinit, Gordon S Mitchell
Moderate acute intermittent hypoxia (mAIH) elicits a form of respiratory motor plasticity known as phrenic long-term facilitation (pLTF). Preconditioning with modest protocols of chronic intermittent hypoxia enhances pLTF, demonstrating pLTF metaplasticity. Since "low dose" protocols of repetitive acute intermittent hypoxia show promise as a therapeutic modality to restore respiratory (and non-respiratory) motor function in clinical disorders with compromised breathing, we tested the hypothesis that preconditioning with a mild repetitive AIH (rAIH) protocol enhances pLTF and hypoglossal (XII) LTF, and whether the enhancement is regulated by glycolytic flux...
October 11, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28973619/effect-of-routine-low-dose-oxygen-supplementation-on-death-and-disability-in-adults-with-acute-stroke-the-stroke-oxygen-study-randomized-clinical-trial
#2
RANDOMIZED CONTROLLED TRIAL
Christine Roffe, Tracy Nevatte, Julius Sim, Jon Bishop, Natalie Ives, Phillip Ferdinand, Richard Gray
Importance: Hypoxia is common in the first few days after acute stroke, is frequently intermittent, and is often undetected. Oxygen supplementation could prevent hypoxia and secondary neurological deterioration and thus has the potential to improve recovery. Objective: To assess whether routine prophylactic low-dose oxygen therapy was more effective than control oxygen administration in reducing death and disability at 90 days, and if so, whether oxygen given at night only, when hypoxia is most frequent, and oxygen administration is least likely to interfere with rehabilitation, was more effective than continuous supplementation...
September 26, 2017: JAMA: the Journal of the American Medical Association
https://www.readbyqxmd.com/read/28972191/effects-of-acute-intermittent-hypoxia-on-hand-use-after-spinal-cord-trauma-a-preliminary-study
#3
Randy D Trumbower, Heather B Hayes, Gordon S Mitchell, Steven L Wolf, Victoria A Stahl
OBJECTIVE: To test the hypothesis that daily acute intermittent hypoxia (AIH) combined with hand opening practice improves hand dexterity, function, and maximum hand opening in persons with chronic, motor-incomplete, cervical spinal cord injury. METHODS: Six participants completed the double-blind, crossover study. Participants received daily (5 consecutive days) AIH (15 episodes per day: 1.5 minutes of fraction of inspired oxygen [FIo2] = 0.09, 1-minute normoxic intervals) followed by 20 repetitions of hand opening practice and normoxia (sham, FIo2 = 0...
September 29, 2017: Neurology
https://www.readbyqxmd.com/read/28822818/phrenic-long-term-facilitation-following-intrapleural-ctb-sap-induced-respiratory-motor-neuron-death
#4
Nicole L Nichols, Taylor A Craig, Miles A Tanner
Amyotrophic lateral sclerosis (ALS) is a devastating disease leading to progressive motor neuron degeneration and death by ventilatory failure. In a rat model of ALS (SOD1(G93A)), phrenic long-term facilitation (pLTF) following acute intermittent hypoxia (AIH) is enhanced greater than expected at disease end-stage but the mechanism is unknown. We suggest that one trigger for this enhancement is motor neuron death itself. Intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) selectively kill respiratory motor neurons and mimic motor neuron death observed in SOD1(G93A) rats...
August 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28758418/intermittent-hypoxia-training-in-prediabetes-patients-beneficial-effects-on-glucose-homeostasis-hypoxia-tolerance-and-gene-expression
#5
Tetiana V Serebrovska, Alla G Portnychenko, Tetiana I Drevytska, Vladimir I Portnichenko, Lei Xi, Egor Egorov, Anna V Gavalko, Svitlana Naskalova, Valentina Chizhova, Valeriy B Shatylo
The present study aimed at examining beneficial effects of intermittent hypoxia training (IHT) under prediabetic conditions. We investigate the effects of three-week IHT on blood glucose level, tolerance to acute hypoxia, and leukocyte mRNA expression of hypoxia inducible factor 1α (HIF-1α) and its target genes, i.e. insulin receptor, facilitated glucose transporter-solute carrier family-2, and potassium voltage-gated channel subfamily J. Seven healthy and 11 prediabetic men and women (44-70 years of age) were examined before, next day and one month after three-week IHT (3 sessions per week, each session consisting 4 cycles of 5-min 12% O2 and 5-min room air breathing)...
September 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28751456/intermittent-hypoxia-enhances-functional-connectivity-of-midcervical-spinal-interneurons
#6
Kristi A Streeter, Michael D Sunshine, Shreya Patel, Elisa J Gonzalez-Rothi, Paul J Reier, David M Baekey, David D Fuller
Brief, intermittent oxygen reductions [acute intermittent hypoxia (AIH)] evokes spinal plasticity. Models of AIH-induced neuroplasticity have focused on motoneurons; however, most midcervical interneurons (C-INs) also respond to hypoxia. We hypothesized that AIH would alter the functional connectivity between C-INs and induce persistent changes in discharge. Bilateral phrenic nerve activity was recorded in anesthetized and ventilated adult male rats and a multielectrode array was used to record C4/5 spinal discharge before [baseline (BL)], during, and 15 min after three 5 min hypoxic episodes (11% O2, H1-H3)...
August 30, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28744643/involvement-of-autonomic-nervous-system-in-antiarrhythmic-effect-of-intermittent-hypobaric-hypoxia
#7
N V Naryzhnaya, A V Mukhamedzyanov, T V Lasukova, L N Maslov
We studied the involvement of the autonomic nervous system in the antiarrhythmic effect of intermittent hypobaric hypoxia modeled by daily placing the rats into an altitude chamber at 405 mm Hg (5000 m above sea level). The antiarrhythmic effect of hypoxia was observed on the model of acute coronary occlusion/reperfusion in vivo, but not during simulation of total ischemia/reperfusion of the isolated myocardium. Intravenous injection of ganglionic blocker hexamethonium (30 mg/kg) 15 min prior to in vivo coronary occlusion modeling abolished the antiarrhythmic effect of intermittent hypobaric hypoxia, which suggests that this effect is mediated via activation of the autonomic nervous system...
July 25, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28686686/protective-effect-of-zinc-preconditioning-against-renal-ischemia-reperfusion-injury-is-dose-dependent
#8
Kenny Rao, Kapil Sethi, Joseph Ischia, Luke Gibson, Laurence Galea, Lin Xiao, Mildred Yim, Mike Chang, Nathan Papa, Damien Bolton, Arthur Shulkes, Graham S Baldwin, Oneel Patel
OBJECTIVES: Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury and chronic kidney disease. Two promising preconditioning methods for the kidney, intermittent arterial clamping (IC) and treatment with the hypoxia mimetic cobalt chloride, have never been directly compared. Furthermore, the protective efficacy of the chemically related transition metal Zn2+ against renal IRI is unclear. Although Co2+ ions have been shown to protect the kidney via hypoxia inducible factor (HIF), the effect of Zn2+ ions on the induction of HIF1α, HIF2α and HIF3α has not been investigated previously...
2017: PloS One
https://www.readbyqxmd.com/read/28620058/intermittent-hypercapnic-hypoxia-during-sleep-does-not-induce-ventilatory-long-term-facilitation-in-healthy-males
#9
Naomi Louise Deacon, Doug R McEvoy, Daniel L Stadler, Peter G Catcheside
Intermittent hypoxia induced ventilatory neuroplasticity is likely important in obstructive sleep apnea pathophysiology. Although concomitant CO2 levels and arousal state critically influence neuroplastic effects of intermittent hypoxia, no studies have investigated intermittent hypercapnic hypoxia effects during sleep in humans. Thus, the purpose of this study was to investigate if intermittent hypercapnic hypoxia during sleep induces neuroplasticity (ventilatory long-term facilitation and increased chemoreflex responsiveness) in humans...
June 15, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28592693/nongenomic-actions-of-17-%C3%AE-estradiol-restore-respiratory-neuroplasticity-in-young-ovariectomized-female-rats
#10
Brendan J Dougherty, Elizabeth S Kopp, Jyoti J Watters
Gonadal steroids modulate CNS plasticity, including phrenic long-term facilitation (pLTF), a form of spinal respiratory neuroplasticity resulting in increased phrenic nerve motor output following exposure to acute intermittent hypoxia (aIH; three 5 min episodes, 10.5% O2). Despite the importance of respiratory system neuroplasticity, and its dependence on estrogen in males, little is known about pLTF expression or mechanisms of estrogen signaling in females. Here, we tested the hypotheses that (1) pLTF expression in young, gonadally intact female rats would be expressed during estrous cycle stages in which 17β-estradiol (E2) is naturally high (e...
July 12, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28585890/hypoxic-conditioning-and-the-central-nervous-system-a-new-therapeutic-opportunity-for-brain-and-spinal-cord-injuries
#11
REVIEW
S Baillieul, S Chacaroun, S Doutreleau, O Detante, J L Pépin, S Verges
Central nervous system diseases are among the most disabling in the world. Neuroprotection and brain recovery from either acute or chronic neurodegeneration still represent a challenge in neurology and neurorehabilitation as pharmacology treatments are often insufficiently effective. Conditioning the central nervous system has been proposed as a potential non-pharmacological neuro-therapeutic. Conditioning refers to a procedure by which a potentially deleterious stimulus is applied near to but below the threshold of damage to the organism to increase resistance to the same or even different noxious stimuli given above the threshold of damage...
June 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28567018/acute-normobaric-hypoxia-increases-post-exercise-lipid-oxidation-in-healthy-males
#12
Liam P Kelly, Fabien A Basset
The primary objective of the current study was to determine the effect of moderate normobaric hypoxia exposure during constant load cycling on post-exercise energy metabolism recorded in normoxia. Indirect calorimetry was used to examine whole body substrate oxidation before, during, 40-60 min post, and 22 h after performing 60 min of cycling exercise at two different fractions of inspired oxygen (FIO2): (i) FIO2 = 0.2091 (normoxia) and (ii) FIO2 = 0.15 (hypoxia). Seven active healthy male participants (26 ± 4 years of age) completed both experimental trials in randomized order with a 7-day washout period to avoid carryover effects between conditions...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28549897/daily-acute-intermittent-hypoxia-improves-breathing-function-with-acute-and-chronic-spinal-injury-via-distinct-mechanisms
#13
B J Dougherty, J Terada, S R Springborn, S Vinit, P M MacFarlane, G S Mitchell
Daily acute intermittent hypoxia (dAIH) elicits respiratory plasticity, enhancing respiratory motor output and restoring breathing capacity after incomplete cervical spinal injuries (cSCI). We hypothesized that dAIH-induced functional recovery of breathing capacity would occur after both acute (2 weeks) and chronic (8 weeks) cSCI, but through distinct cellular mechanisms. Specifically, we hypothesized that dAIH-induced breathing recovery would occur through serotonin-independent mechanisms 2wks post C2 cervical hemisection (C2Hs), versus serotonin-dependent mechanisms 8wks post C2Hs...
May 24, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28522758/regulation-of-erythropoiesis-after-normoxic-return-from-chronic-sustained-and-intermittent-hypoxia
#14
Jihyun Song, Krishna Sundar, Radhika Gangaraju, Josef T Prchal
Hypoxia increases erythropoiesis mediated by hypoxia-inducible transcription factors (HIF) which regulate erythropoietin (EPO) transcription. Neocytolysis is a physiological mechanism that corrects polycythemia from chronic sustained hypoxemia (CSH) by transient, preferential destruction of young RBCs after normoxia is restored. We showed that neocytolysis is caused by excessive mitochondrial-derived reactive oxygen species (ROS) in reticulocytes mediated by down-regulation of HIF-controlled BNIP3L regulated mitophagy and a decrease in RBC antioxidant catalase (CAT) in hypoxia-produced erythrocytes...
May 18, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28506824/hypoxia-and-nicotine-effects-on-pituitary-adenylate-cyclase-activating-polypeptide-pacap-and-its-receptor-1-pac1-in-the-developing-piglet-brainstem
#15
J Huang, K A Waters, R Machaalani
Pituitary adenylate cyclase activating polypeptide (PACAP) and its cognate receptor 1 (PAC1), have been implicated in the pathophysiology of the Sudden Infant Death Syndrome (SIDS). Two main risk factors for SIDS are prone sleeping and cigarette smoke exposure. Using piglet models of these risk factors, intermittent hypercapnic hypoxia (IHH-mimicking rebreathing in prone position) and nicotine (main reinforcing element of cigarettes), this study aimed to determine their effects on PACAP and PAC1 protein expression in the medulla...
September 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28500219/mechanisms-of-enhanced-phrenic-long-term-facilitation-in-sod1-g93a-rats
#16
Nicole L Nichols, Irawan Satriotomo, Latoya L Allen, Ashley M Grebe, Gordon S Mitchell
Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disease, causing muscle paralysis and death from respiratory failure. Effective means to preserve/restore ventilation are necessary to increase the quality and duration of life in ALS patients. At disease end-stage in a rat ALS model (SOD1(G93A) ), acute intermittent hypoxia (AIH) restores phrenic nerve activity to normal levels via enhanced phrenic long-term facilitation (pLTF). Mechanisms enhancing pLTF in end-stage SOD1(G93A) rats are not known...
June 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28483998/hypoxia-treatment-reverses-neurodegenerative-disease-in-a-mouse-model-of-leigh-syndrome
#17
Michele Ferrari, Isha H Jain, Olga Goldberger, Emanuele Rezoagli, Robrecht Thoonen, Kai-Hung Chen, David E Sosnovik, Marielle Scherrer-Crosbie, Vamsi K Mootha, Warren M Zapol
The most common pediatric mitochondrial disease is Leigh syndrome, an episodic, subacute neurodegeneration that can lead to death within the first few years of life, for which there are no proven general therapies. Mice lacking the complex I subunit, Ndufs4, develop a fatal progressive encephalopathy resembling Leigh syndrome and die at ≈60 d of age. We previously reported that continuously breathing normobaric 11% O2 from an early age prevents neurological disease and dramatically improves survival in these mice...
May 23, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28464406/sustained-apnea-induces-endothelial-activation
#18
Lars Eichhorn, Ramona Dolscheid-Pommerich, Felix Erdfelder, Muhammad Ajmal Ayub, Theresa Schmitz, Nikos Werner, Felix Jansen
BACKGROUND: Apnea diving has gained worldwide popularity, even though the pathophysiological consequences of this challenging sport on the human body are poorly investigated and understood. This study aims to assess the influence of sustained apnea in healthy volunteers on circulating microparticles (MPs) and microRNAs (miRs), which are established biomarkers reflecting vascular function. HYPOTHESIS: Short intermittent hypoxia due to voluntary breath-holding affects circulating levels of endothelial cell-derived MPs (EMPs) and endothelial cell-derived miRs...
September 2017: Clinical Cardiology
https://www.readbyqxmd.com/read/28459156/antioxidant-tempol-suppresses-heart-cytosolic-phospholipase-a2%C3%AE-stimulated-by-chronic-intermittent-hypoxia
#19
Petra Míčová, Martina Klevstig, Kristýna Holzerová, Marek Vecka, Jitka Žurmanová, Jan Neckář, František Kolář, Olga Nováková, Jiří Novotný, Markéta Hlaváčková
Adaptation to chronic intermittent hypoxia (CIH) is associated with reactive oxygen species (ROS) generation implicated in the improved cardiac tolerance against acute ischemia-reperfusion injury. Phospholipases A2 (PLA2s) play an important role in cardiomyocyte phospholipid metabolism influencing membrane homeostasis. Here we aimed to determine the effect of CIH (7000 m, 8 h/day, 5 weeks) on the expression of cytosolic PLA2 (cPLA2α), its phosphorylated form (p-cPLA2α), calcium-independent (iPLA2), and secretory (sPLA2IIA) at protein and mRNA levels, as well as fatty acids (FA) profile in left ventricular myocardium of adult male Wistar rats...
August 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28451849/role-of-carotid-body-in-intermittent-hypoxia-related-hypertension
#20
REVIEW
Rodrigo Iturriaga, María Paz Oyarce, Ana Carolina Rodrigues Dias
Obstructive sleep apnea (OSA), a common breathing disorder, is recognized as an independent risk factor for systemic hypertension. Among the alterations induced by OSA, the chronic intermittent hypoxia (CIH) is considered the main factor for the hypertension. Exposure of rodents to CIH is the gold-standard method to study the mechanisms involved in the cardiovascular alterations induced by OSA. Although it is well known that CIH produces hypertension, the underlying mechanisms are not totally elucidated. It is likely that the CIH-induced systemic oxidative stress and inflammation may elicit endothelial dysfunction and increase the arterial blood pressure...
May 2017: Current Hypertension Reports
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