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acute intermittent hypoxia

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https://www.readbyqxmd.com/read/28167915/the-role-of-acute-intermittent-hypoxia-in-neutrophil-generated-superoxide-sympathovagal-balance-and-vascular-function-in-healthy-subjects
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
Ibis M Agosto-Marlin, Nicole L Nichols, Gordon S Mitchell
Phrenic motor facilitation (pMF) can be elicited by acute intermittent hypoxia (ie. phrenic long-term facilitation, or pLTF), or direct application of pharmacological agonists to the cervical spinal cord. Moderate acute intermittent hypoxia (mAIH, 3X5 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 even low levels of systemic inflammation induced by lipopolysaccharide (LPS, 100ug/kg i.p.). In contrast, severe AIH (sAIH, 3X5 min episodes of 25-30mmHg arterial PO2, 5 min intervals) elicits pLTF by a distinct, adenosine-dependent mechanism...
December 7, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/27925282/hypobaric-hypoxia-regulates-brain-iron-homeostasis-in-rats
#9
Yaru Li, Peng Yu, Shi-Yang Chang, Qiong Wu, Panpan Yu, Congcong Xie, Wenyue Wu, Baolu Zhao, Guofen Gao, Yan-Zhong Chang
Disruption of iron homeostasis in brain has been found to be closely involved in several neurodegenerative diseases. Recent studies have reported that appropriate intermittent hypobaric hypoxia played a protective role in brain injury caused by acute hypoxia. However, the mechanisms of this protective effect have not been fully understood. In this study, Sprague-Dawley (SD) rat models were developed by hypobaric hypoxia treatment in an altitude chamber, and the iron level and iron related protein levels were determined in rat brain after 4 weeks of treatment...
December 6, 2016: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/27884793/sex-stress-and-sleep-apnoea-decreased-susceptibility-to-upper-airway-muscle-dysfunction-following-intermittent-hypoxia-in-females
#10
REVIEW
Ken D O'Halloran, Philip Lewis, Fiona McDonald
Obstructive sleep apnoea syndrome (OSAS) is a devastating respiratory control disorder more common in men than women. The reasons for the sex difference in prevalence are multifactorial, but are partly attributable to protective effects of oestrogen. Indeed, OSAS prevalence increases in post-menopausal women. OSAS is characterized by repeated occlusions of the pharyngeal airway during sleep. Dysfunction of the upper airway muscles controlling airway calibre and collapsibility is implicated in the pathophysiology of OSAS, and sex differences in the neuro-mechanical control of upper airway patency are described...
November 21, 2016: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/27800512/chronic-intermittent-hypoxia-and-obstructive-sleep-apnea-an-experimental-and-clinical-approach
#11
REVIEW
Emilia Sforza, Fréderic Roche
Obstructive sleep apnea (OSA) is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences, such as systemic arterial hypertension, ischemic heart disease, cardiac arrhythmias, metabolic disorders, and cognitive dysfunction. The pathogenesis of OSA-related consequence is assumed to be chronic intermittent hypoxia (IH) inducing alterations at the molecular level, oxidative stress, persistent systemic inflammation, oxygen sensor activation, and increase of sympathetic activity...
2016: Hypoxia
https://www.readbyqxmd.com/read/27699083/oxidative-stress-induced-telomere-length-shortening-of-circulating-leukocyte-in-patients-with-obstructive-sleep-apnea
#12
Kyung Soo Kim, Jin Wook Kwak, Su Jin Lim, Yong Kyun Park, Hoon Shik Yang, Hyun Jik Kim
The main mechanism of pathogenesis which causes systemic complications in obstructive sleep apnea (OSA) patients is believed to be intermittent hypoxia-induced intermediary effect and it depends on the burden of oxidative stress during sleep. We aimed to search the predictive markers which reflect the burden of systemic oxidative stress in patients with OSA and whether excessive telomere length shortening is a characteristic feature that can assess oxidative stress levels. We used quantitative PCR to measure telomere length using peripheral blood genomic DNA...
October 2016: Aging and Disease
https://www.readbyqxmd.com/read/27686454/chronic-intermittent-hypoxia-affects-the-cytosolic-phospholipase-a2%C3%AE-cyclooxygenase-2-pathway-via-%C3%AE-2-adrenoceptor-mediated-erk-p38-stimulation
#13
Petra Micova, Klara Hahnova, Marketa Hlavackova, Barbara Elsnicova, Anna Chytilova, Kristyna Holzerova, Jitka Zurmanova, Jan Neckar, Frantisek Kolar, Olga Novakova, Jiri Novotny
Cardiac resistance against acute ischemia/reperfusion (I/R) injury can be enhanced by adaptation to chronic intermittent hypoxia (CIH), but the changes at the molecular level associated with this adaptation are still not fully explored. Phospholipase A2 (PLA2) plays an important role in phospholipid metabolism and may contribute to membrane destruction under conditions of energy deprivation during I/R. The aim of this study was to determine the effect of CIH (7000 m, 8 h/day, 5 weeks) on the expression of cytosolic PLA2α (cPLA2α) and its phosphorylated form (p-cPLA2α), as well as other related signaling proteins in the left ventricular myocardium of adult male Wistar rats...
December 2016: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/27660299/generation-of-active-expiration-by-serotoninergic-mechanisms-of-the-ventral-medulla-of-rats
#14
Eduardo V Lemes, Eduardo Colombari, Daniel B Zoccal
Abdominal expiratory activity is absent at rest and is evoked during metabolic challenges, such as hypercapnia and hypoxia, or after the exposure to intermittent hypoxia (IH). The mechanisms engaged during this process are not completely understood. In this study, we hypothesized that serotonin (5-HT), acting in the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG), is able to generate active expiration. In anesthetized (urethane, ip), tracheostomized, spontaneously-breathing adult male Holtzman rats we microinjected a serotoninergic agonist and antagonist bilaterally in the RTN/pFRG and recorded diaphragm and abdominal muscle activities...
November 1, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27609199/heme-oxygenase-1-dependent-central-cardiorespiratory-adaptations-to-chronic-intermittent-hypoxia-in-mice
#15
Jag Sunderram, John Semmlow, Pranav Patel, Harshit Rao, Glen Chun, Priya Agarwala, Mantu Bhaumik, Oanh Le-Hoang, Shou-En Lu, Judith A Neubauer
Chronic intermittent hypoxia (CIH) increases sympathetic tone, and respiratory instability. Our previous work showed that chronic hypoxia induces the oxygen sensing enzyme, heme oxygenase-1 (HO-1) within the C1 sympathoexcitatory region and the pre-Bötzinger complex (pre-BötC). We therefore examined the effect of CIH on time course of induced expression of HO-1 within these regions and determined whether the induction of HO-1 correlated with changes in respiratory, sigh frequency, and sympathetic responses (spectral analysis of heart rate) to acute hypoxia (10%O2) during 10 days of exposure to CIH in chronically instrumented awake wild type (WT) and HO-1 null mice (HO-1(-/-))...
September 8, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27595979/oxidative-stress-augments-chemoreflex-sensitivity-in-rats-exposed-to-chronic-intermittent-hypoxia
#16
Barbara J Morgan, Melissa L Bates, Rodrigo Del Rio, Zunyi Wang, John M Dopp
Chronic exposure to intermittent hypoxia (CIH) elicits plasticity of the carotid sinus and phrenic nerves via reactive oxygen species (ROS). To determine whether CIH-induced alterations in ventilation, metabolism, and heart rate are also dependent on ROS, we measured responses to acute hypoxia in conscious rats after 14 and 21 d of either CIH or normoxia (NORM), with or without concomitant administration of allopurinol (xanthine oxidase inhibitor), combined allopurinol plus losartan (angiotensin II type 1 receptor antagonist), or apocynin (NADPH oxidase inhibitor)...
December 2016: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/27496218/high-variability-in-the-reported-management-of-hepatic-veno-occlusive-disease-in-children-after-hematopoietic-stem-cell-transplantation
#17
Micah A Skeens, Jennifer McArthur, Ira M Cheifetz, Christine Duncan, Adrienne G Randolph, Joseph Stanek, Leslie Lehman, Rajinder Bajwa
Veno-occlusive disease (VOD) is a potentially fatal complication of hematopoietic stem cell transplantation (HSCT). Patients with VOD are often critically ill and require close collaboration between transplant physicians and intensivists. We surveyed members of a consortium of pediatric intensive care unit (PICU) and transplant physicians to assess variability in the self-reported approach to the diagnosis and management of VOD. An internet-based self-administered survey was sent to pediatric HSCT and PICU providers from September 2014 to February 2015...
October 2016: Biology of Blood and Marrow Transplantation
https://www.readbyqxmd.com/read/27466333/sustained-hypoxia-elicits-competing-spinal-mechanisms-of-phrenic-motor-facilitation
#18
Michael J Devinney, Nicole L Nichols, Gordon S Mitchell
UNLABELLED: Acute intermittent hypoxia (AIH) induces phrenic long-term facilitation (pLTF), a form of spinal motor plasticity. Competing mechanisms give rise to phrenic motor facilitation (pMF; a general term including pLTF) depending on the severity of hypoxia within episodes. In contrast, moderate acute sustained hypoxia (mASH) does not elicit pMF. By varying the severity of ASH and targeting competing mechanisms of pMF, we sought to illustrate why moderate AIH (mAIH) elicits pMF but mASH does not...
July 27, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27421877/effects-of-acute-hypoxia-on-human-adipose-tissue-lipoprotein-lipase-activity-and-lipolysis
#19
Bimit Mahat, Étienne Chassé, Jean-François Mauger, Pascal Imbeault
BACKGROUND: Adipose tissue regulates postprandial lipid metabolism by storing dietary fat through lipoprotein lipase-mediated hydrolysis of exogenous triglycerides, and by inhibiting delivery of endogenous non-esterified fatty acid to nonadipose tissues. Animal studies show that acute hypoxia, a model of obstructive sleep apnea, reduces adipose tissue lipoprotein lipase activity and increases non-esterified fatty acid release, adversely affecting postprandial lipemia. These observations remain to be tested in humans...
2016: Journal of Translational Medicine
https://www.readbyqxmd.com/read/27384072/intrathecal-intermittent-orexin-a-causes-sympathetic-long-term-facilitation-and-sensitizes-the-peripheral-chemoreceptor-response-to-hypoxia-in-rats
#20
Seung Jae Kim, Paul M Pilowsky, Melissa M J Farnham
Intermittent hypoxia causes a persistent increase in sympathetic nerve activity (SNA), which progresses to hypertension in conditions such as obstructive sleep apnea. Orexins (A and B) are hypothalamic neurotransmitters with arousal-promoting and sympathoexcitatory effects. We investigated whether the sustained elevation of SNA, termed sympathetic long-term facilitation, after acute intermittent hypoxia (AIH) is caused by endogenous orexin acting on spinal sympathetic preganglionic neurons. The role of orexin in the increased SNA response to AIH was investigated in urethane-anesthetized, vagotomized, and artificially ventilated Sprague-Dawley rats (n = 58)...
September 2016: Journal of Pharmacology and Experimental Therapeutics
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