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acute intermittent hypoxia

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https://www.readbyqxmd.com/read/28522758/regulation-of-erythropoiesis-after-normoxic-return-from-chronic-sustained-and-intermittent-hypoxia
#1
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
#2
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...
May 12, 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28500219/mechanisms-of-enhanced-phrenic-long-term-facilitation-in-sod1-g93a-rats
#3
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...
May 12, 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
#4
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 8, 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
#5
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...
May 2, 2017: Clinical Cardiology
https://www.readbyqxmd.com/read/28459156/antioxidant-tempol-supresses-heart-cytosolic-phospholipase-a-sub-2-sub-%C3%AE-stimulated-by-chronic-intermittent-hypoxia
#6
Petra Micova, Martina Klevstig, Kristyna Holzerova, Marek Vecka, Jitka Zurmanova, Jan Neckar, Frantisek Kolar, Olga Novakova, Jiri Novotny, Marketa Hlavackova
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 A<sub>2</sub> (PLA<sub>2</sub>s) play an important role in cardiomyocyte phospholipid metabolism influencing membrane homeostasis. Here we aimed to determine the effect of CIH (7000 m, 8h/day, 5 weeks) on the expression of cytosolic PLA<sub>2</sub> (cPLA<sub>2</sub>α), its phosphorylated form (p-cPLA<sub>2</sub>α), calcium-independent (iPLA<sub>2</sub>) and secretory (sPLA<sub>2</sub>IIA) at protein and mRNA levels as well fatty acids (FA) profile in left ventricular myocardium of adult male Wistar rats...
April 30, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28451849/role-of-carotid-body-in-intermittent-hypoxia-related-hypertension
#7
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
https://www.readbyqxmd.com/read/28413125/transient-dysautonomia-in-an-acute-phase-of-encephalopathy-with-biphasic-seizures-and-late-reduced-diffusion
#8
Yuko Ichimiya, Noriyuki Kaku, Yasunari Sakai, Fumiya Yamashita, Wakato Matsuoka, Mamoru Muraoka, Satoshi Akamine, Soichi Mizuguchi, Michiko Torio, Yoshitomo Motomura, Yuichiro Hirata, Yoshito Ishizaki, Masafumi Sanefuji, Hiroyuki Torisu, Hidetoshi Takada, Yoshihiko Maehara, Shouichi Ohga
Paroxysmal sympathetic hyperactivity (PSH) is a dysautonomic condition that is associated with various types of acquired brain injuries. Traumatic brain lesions have been documented as the leading cause of PSH. However, detailed clinical features of pediatric PSH caused by intrinsic brain lesions remain to be elusive. We present a 3-year-old boy, who had been diagnosed as having cerebral palsy, developmental delay and epilepsy after perinatal hypoxia-induced brain injury. He developed status epilepticus with fever on the third day of respiratory infection...
April 13, 2017: Brain & Development
https://www.readbyqxmd.com/read/28386237/prediction-of-critical-power-and-w-in-hypoxia-application-to-work-balance-modelling
#9
Nathan E Townsend, David S Nichols, Philip F Skiba, Sebastien Racinais, Julien D Périard
Purpose: Develop a prediction equation for critical power (CP) and work above CP (W') in hypoxia for use in the work-balance ([Formula: see text]) model. Methods: Nine trained male cyclists completed cycling time trials (TT; 12, 7, and 3 min) to determine CP and W' at five altitudes (250, 1,250, 2,250, 3,250, and 4,250 m). Least squares regression was used to predict CP and W' at altitude. A high-intensity intermittent test (HIIT) was performed at 250 and 2,250 m. Actual and predicted CP and W' were used to compute W' during HIIT using differential ([Formula: see text]) and integral ([Formula: see text]) forms of the [Formula: see text] model...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28332435/mild-acute-intermittent-hypoxia-improves-respiratory-function-in-unanesthetized-rats-with-midcervical-contusion
#10
Kun-Ze Lee, Shu-Chi Chiang, Yu-Jie Li
BACKGROUND: Mild intermittent hypoxia has been considered a potential approach to induce respiratory neuroplasticity. OBJECTIVE: The purpose of the present study was to investigate whether mild acute intermittent hypoxia can improve breathing function in a clinically relevant spinal cord injury animal model. METHODS: Adult male rats received laminectomy or unilateral contusion at the C3-C4 spinal cord using a MASCIS Impactor (height: 6.25 or 12...
April 2017: Neurorehabilitation and Neural Repair
https://www.readbyqxmd.com/read/28238671/cardiac-autonomic-ganglia-ablation-suppresses-atrial-fibrillation-in-a-canine-model-of-acute-intermittent-hypoxia
#11
Xiaomei Yu, Zhibing Lu, Wenbo He, Bo He, Ruisong Ma, Jing Xie, Hong Jiang
BACKGROUND: Atrial fibrillation (AF) is associated with hypoxia in which cardiac autonomic nerve system (ANS) plays an important role. Our previous studies indicated that ANS is activated in an intermittent hypoxia model and contributes to AF initiation. This study aimed to investigate the effects of cardiac ganglionated plexus (GP) ablation on AF in this model. METHODS AND RESULTS: In thirteen anesthetized male dogs, GP ablation was applied after 1h of intermittent hypoxia in the first group (n=7) and before that in the second group (n=6)...
February 23, 2017: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28235547/intermittent-hypercapnic-hypoxia-effects-on-the-nicotinic-acetylcholine-receptors-in-the-developing-piglet-hippocampus-and-brainstem
#12
Arunnjah Vivekanandarajah, Atqiya Aishah, Karen A Waters, Rita Machaalani
This study investigated the effects of acute (1 day) vs repeated (4 days) exposure to intermittent hypercapnic hypoxia (IHH) on the immunohistochemical expression of α2, α3, α5, α7, α9 and β2 nicotinic acetylcholine receptor (nAChR) subunits in the developing piglet hippocampus and brainstem medulla, and how prior nicotine exposure alters the response to acute IHH. Five piglet groups included: 1day IHH (1D IHH, n=9), 4days IHH (4D IHH, n=8), controls exposed only to air cycles for 1day (1D Air, n=6) or 4days (4D Air, n=5), and pre-exposed to nicotine for 13days prior to 1day IHH (Nic+1D IHH, n=7)...
February 22, 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28167915/the-role-of-acute-intermittent-hypoxia-in-neutrophil-generated-superoxide-sympathovagal-balance-and-vascular-function-in-healthy-subjects
#13
Germana P L Almeida, Ivani C Trombetta, Felipe X Cepeda, Elaine Hatanaka, Rui Curi, Cristiano Mostarda, Maria C Irigoyen, José A S Barreto-Filho, Eduardo M Krieger, Fernanda M Consolim-Colombo
Introduction: Recurrent hypoxia (HPX), a hallmark of the obstructive sleep apnea (OSA), impairs autonomic balance, and increases arterial blood pressure (BP). Oxidative stress is one of the mechanisms involved in these alterations. The cumulative effect of acute intermittent HPX and the chronicity may determine whether the response crosses the threshold from having protective value to pathology. However, the impact of acute intermittent HPX-reoxygenation on markers of oxidative stress in healthy individuals remains to be fully understood...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28087818/three-hours-of-intermittent-hypoxia-increases-circulating-glucose-levels-in-healthy-adults
#14
Lauren P Newhouse, Michael J Joyner, Timothy B Curry, Marcello C Laurenti, Chiara Dalla Man, Claudio Cobelli, Adrian Vella, Jacqueline K Limberg
An independent association exists between sleep apnea and diabetes. Animal models suggest exposure to intermittent hypoxia, a consequence of sleep apnea, results in altered glucose metabolism and fasting hyperglycemia. However, it is unknown if acute exposure to intermittent hypoxia increases glucose concentrations in nondiabetic humans. We hypothesized plasma glucose would be increased from baseline following 3 h of intermittent hypoxia in healthy humans independent of any effect on insulin sensitivity. Eight (7M/1F, 21-34 years) healthy subjects completed two study visits randomized to 3 h of intermittent hypoxia or continuous normoxia, followed by an oral glucose tolerance test...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28068279/identifying-predictors-of-central-sleep-apnea-cheyne-stokes-breathing-in-chronic-heart-failure-a-pathophysiological-approach
#15
Aneliya I Draganova, Kiril V Terziyski, Stefan S Kostianev
Chronic heart failure (CHF) is a major health problem associated with increased mortality, despite modern treatment options. Central sleep apnea (CSA)/Cheyne-Stokes breathing (CSB) is a common and yet largely under-diagnosed co-morbidity, adding significantly to the poor prognosis in CHF because of a number of acute and chronic effects, including intermittent hypoxia, sympathetic overactivation, disturbed sleep architecture and impaired physical tolerance. It is characterized by repetitive periods of crescendo-decrescendo ventilatory pattern, alternating with central apneas and hypopneas...
December 1, 2016: Folia Medica
https://www.readbyqxmd.com/read/28060323/a-model-to-simulate-clinically-relevant-hypoxia-in-humans
#16
Lars Eichhorn, Florian Kessler, Volker Böhnert, Felix Erdfelder, Anja Reckendorf, Rainer Meyer, Richard K Ellerkmann
In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to hypoxia sensitive organs such as the brain, compensatory circulatory mechanisms help to maintain an adequate oxygen supply. This is mainly achieved by increased cerebral blood flow. Intermittent hypoxia is a commonly seen phenomenon in patients with obstructive sleep apnea. Acute airway obstruction can also result in hypoxia and hypercapnia. Until now, no adequate model has been established to simulate these dynamics in humans...
December 22, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28048423/we-fg-bra-08-potential-role-of-the-glycolytic-oscillator-in-acute-hypoxia-in-tumors
#17
L Che Fru, E Adamson, D Campos, S Fain, S Jacques, A van der Kogel, K Nickel, C Song, R Kimple, M Kissick
PURPOSE: Oscillatory dynamics in acute hypoxia have been observed, but poorly understood. They have mostly been attributed to vascular perturbations, but no link has yet been made to metabolic causes. We set out to determine the fundamental frequencies and test for coherence in tumor oxygen dynamics and spatial properties. METHODS: Severe combined immunodeficient (SCID) mice were inoculated onto bilateral flanks with human derived head and neck carcinoma (UW-SCC22) cell line xenografts...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28018235/modulation-of-muscle-fiber-compositions-in-response-to-hypoxia-via-pyruvate-dehydrogenase-kinase-1
#18
Daniel D Nguyen, Gyuyoup Kim, Eung-Kwon Pae
Muscle fiber-type changes in hypoxic conditions in accordance with pyruvate dehydrogenase kinase (Pdk)-1 and hypoxia inducible factor (Hif)-1α were investigated in rats. Hif-1α and its down-stream molecule Pdk-1 are well known for readily response to hypoxia. We questioned their roles in relation to changes in myosin heavy chain (MyHC) composition in skeletal muscles. We hypothesize that the level of Pdk-1 with respect to the level of Hif-1α determines MyHC composition of the muscle in rats in hypoxia. Young male rats were housed in a chamber maintained at 11...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27932681/acute-intermittent-hypoxia-in-rats-activates-muscle-proteolytic-pathways-through-a-glucocorticoid-dependent-mechanism
#19
Franciele Przygodda, Leandro Henrique Manfredi, Juliano Machado, Dawit A P Gonçalves, Neusa Maria Zanon, Leni G H Bonagamba, Benedito H Machado, Isis do Carmo Kettelhut, Luiz C C Navegantes
Although it is well known that chronic hypoxia induces muscle wasting, the effects of intermit-tent hypoxia on skeletal muscle protein metabolism remains unclear. We hypothesized that acute intermittent hypoxia (AIH), a challenge that activates the hypothalamic-pituitary-adrenal axis, would alter muscle protein homeostasis through a glucocorticoid-dependent mechanism. Three-week-old rats were submitted to adrenalectomy (ADX) and exposed to 8 h of AIH (6% O2 for 40s at 9 min intervals). Animals were sacrificed and the soleus and extensor digitorum longus (EDL) muscles were harvested and incubated in vitro for measurements of protein turn-over...
December 8, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27927784/adenosine-dependent-phrenic-motor-facilitation-is-inflammation-resistant
#20
Ibis M Agosto-Marlin, Nicole L Nichols, Gordon S Mitchell
Phrenic motor facilitation (pMF), a form of respiratory plasticity, can be elicited by acute intermittent hypoxia (i.e., phrenic long-term facilitation, pLTF) or direct application of drugs to the cervical spinal cord. Moderate acute intermittent hypoxia (mAIH; 3 × 5-min episodes of 35-50 mmHg arterial Po2, 5-min normoxic intervals) induces pLTF by a serotonin-dependent mechanism; mAIH-induced pLTF is abolished by mild systemic inflammation induced by a low dose of lipopolysaccharide (LPS; 100 μg/kg ip). In contrast, severe acute intermittent hypoxia (sAIH; 3 × 5-min episodes of 25-30 mmHg arterial Po2, 5-min normoxic intervals) elicits pLTF by a distinct, adenosine-dependent mechanism...
February 1, 2017: Journal of Neurophysiology
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