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Hypoxic vasoconstriction

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https://www.readbyqxmd.com/read/29687908/hepatopulmonary-disorders-gas-exchange-and-vascular-manifestations-in-chronic-liver-disease
#1
Robert Rodríguez-Roisin, Michael J Krowka, Alvar Agustí
This review concentrates on the determinants of gas exchange abnormalities in liver-induced pulmonary vascular disorders, more specifically in the hepatopulmonary syndrome. Increased alveolar-arterial O2 difference, with or without different levels of arterial hypoxemia, and reduced diffusing capacity represent the most characteristic gas exchange disturbances in the absence of cardiac and pulmonary comorbidities. Pulmonary gas exchange abnormalities in the hepatopulmonary syndrome are unique encompassing all three pulmonary factors determining arterial PO2 , that is, ventilation-perfusion imbalance, increased intrapulmonary shunt and oxygen diffusion limitation that, combined, interplay with two relevant nonpulmonary determinants, that is, increased total ventilation and high cardiac output...
March 25, 2018: Comprehensive Physiology
https://www.readbyqxmd.com/read/29660141/carbonic-anhydrase-is-not-a-relevant-nitrite-reductase-or-nitrous-anhydrase-in-the-lung
#2
Philipp A Pickerodt, Sebastian Kronfeldt, Martin Russ, Adrian Gonzalez-Lopez, Philipp Lother, Elvira Steiner, Katja Vorbrodt, Thilo Busch, Willehad Boemke, Roland C E Francis, Erik R Swenson
The carbonic anhydrase (CA) inhibitors, acetazolamide and its structurally similar analogue, methazolamide prevent or reduce hypoxic pulmonary vasoconstriction (HPV) in dogs and humans in vivo, by a mechanism unrelated to CA inhibition. In rodent blood and isolated blood vessels, Aamand et al. (2009) reported that inhibition of CA led to increased generation of nitric oxide (NO) from nitrite and vascular relaxation in vitro. We tested the physiological relevance of augmented NO generation by CA from nitrite with acetazolamide in anaesthetized pigs during alveolar hypoxia in vivo...
April 16, 2018: Journal of Physiology
https://www.readbyqxmd.com/read/29629058/effect-of-propofol-and-isoflurane-on-gas-exchange-parameters-following-one-lung-ventilation-in-thoracic-surgery-a-double-blinded-randomized-controlled-clinical-trial
#3
Shima Sheybani, Alireza Sharifian Attar, Sogol Golshan, Shadi Sheibani, Majid Rajabian
Background: The use of anesthetic drugs with minimal inhibitory effects on the hypoxic pulmonary vasoconstriction (HPV) could have a decisive role in preventing the hypoxemia during one-lung ventilation (OLV). Objective: The aim of this study was to compare the effects of propofol and isoflurane on the changes in gas exchange parameters following OLV in thoracic surgery. Methods: This double-blinded randomized controlled clinical trial was conducted on patients who were candidates for elective right thoracotomy referred to the central operating room of Ghaem Hospital in Mashhad, Iran, during February 2016-2017...
February 2018: Electronic Physician
https://www.readbyqxmd.com/read/29622593/transient-receptor-potential-melastatin-8-activation-induces-relaxation-of-pulmonary-artery-by-inhibition-of-store-operated-calcium-entry-in-normoxic-and-chronic-hypoxic-pulmonary-hypertensive-rats
#4
Yun-Ping Mu, Da-Cen Lin, Si-Yi Zheng, Hai-Xia Jiao, James Sham, Mo-Jun Lin
Pulmonary hypertension (PH) is characterized by enhanced vasoconstriction and vascular remodeling, which are attributable to the alteration of Ca2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). It is well established that store-operated Ca2+ entry (SOCE) is augmented in PASMCs during PH and it plays crucial roles in PH development. Our previous studies showed that the melastatin-related transient receptor potential 8 (TRPM8) is down-regulated in PASMCs of PH animal models; and activation of TRPM8 causes relaxation of pulmonary arteries (PAs)...
April 5, 2018: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/29605474/hemodynamic-mechanisms-of-exercise-induced-pulmonary-hypertension-in-patients-with-lymphangioleiomyomatosis-the-role-of-exercise-stress-echocardiography
#5
Andrea Sonaglioni, Massimo Baravelli, Roberto Cassandro, Olga Torre, Davide Elia, Claudio Anzà, Sergio Harari
BACKGROUND: The pathogenesis of pulmonary hypertension (PH) in lymphangioleiomyomatosis (LAM) has not yet been completely clarified. The aim of this study was to conduct a noninvasive evaluation of the main hemodynamic mechanisms of exercise-induced PH in patients with LAM, assessed using exercise stress echocardiography. METHODS: Fifteen patients with LAM (mean age, 47 ± 13 years; all women) without resting PH were enrolled in a prospective single-center study and compared with 15 healthy female control subjects (mean age, 45...
March 28, 2018: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/29549995/in-shackleton-s-trails-central-and-local-thermoadaptive-modifications-to-cold-and-hypoxia-after-a-man-hauling-expedition-on-the-antarctic-plateau
#6
Michail E Keramidas, Roger Kölegård, Ola Eiken
Cold and hypoxia constitute the main environmental stressors encountered on the Antarctic Plateau. Hence, we examined whether central and/or peripheral acclimatisation to the combined stressors of cold and hypoxia would be developed in four men following an 11-day man-hauling expedition on this polar region. Before and after the journey, participants performed a static whole-body immersion in 21 °C water, during which they were breathing a hypoxic gas (partial pressure of inspired O2 : ~97 mmHg). To evaluate their local responses to cold, participants also immersed the hand into 8 °C water for 30 min, while they were whole-body immersed and mildly hypothermic [i...
April 2018: Journal of Thermal Biology
https://www.readbyqxmd.com/read/29520238/erythrocytes-and-vascular-function-oxygen-and-nitric-oxide
#7
REVIEW
Christine C Helms, Mark T Gladwin, Daniel B Kim-Shapiro
Erythrocytes regulate vascular function through the modulation of oxygen delivery and the scavenging and generation of nitric oxide (NO). First, hemoglobin inside the red blood cell binds oxygen in the lungs and delivers it to tissues throughout the body in an allosterically regulated process, modulated by oxygen, carbon dioxide and proton concentrations. The vasculature responds to low oxygen tensions through vasodilation, further recruiting blood flow and oxygen carrying erythrocytes. Research has shown multiple mechanisms are at play in this classical hypoxic vasodilatory response, with a potential role of red cell derived vasodilatory molecules, such as nitrite derived nitric oxide and red blood cell ATP, considered in the last 20 years...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29488785/highs-and-lows-of-hyperoxia-physiological-performance-and-clinical-aspects
#8
Julien Vincent Brugniaux, Geoff B Coombs, Otto F Barak, Zeljko Dujic, Mypinder S Sekhon, Philip N Ainslie
Molecular oxygen (O2 ) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content (CaO2 ), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e...
February 28, 2018: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/29486465/chronic-prenatal-hypoxia-down-regulated-bk-channel-%C3%AE-1-subunits-in-mesenteric-artery-smooth-muscle-cells-of-the-offspring
#9
Bailin Liu, Yanping Liu, Ruixiu Shi, Xueqin Feng, Xiang Li, Wenna Zhang, Jue Wu, Na Li, Xiuwen Zhou, Miao Sun, Zhice Xu
BACKGROUND/AIMS: Chronic hypoxia in utero could impair vascular functions in the offspring, underlying mechanisms are unclear. This study investigated functional alteration in large-conductance Ca2+-activated K+ (BK) channels in offspring mesenteric arteries following prenatal hypoxia. METHODS: Pregnant rats were exposed to normoxic control (21% O2, Con) or hypoxic (10.5% O2, Hy) conditions from gestational day 5 to 21, their 7-month-old adult male offspring were tested for blood pressure, vascular BK channel functions and expression using patch clamp and wire myograh technique, western blotting, and qRT-PCR...
February 21, 2018: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/29433570/role-of-atp-sensitive-potassium-channels-on-hypoxic-pulmonary-vasoconstriction-in-endotoxemia
#10
Maurizio Turzo, Julian Vaith, Felix Lasitschka, Markus A Weigand, Cornelius J Busch
BACKGROUND: ATP-regulated potassium channels (KATP) regulate pulmonary vascular tone and are involved in hypoxic pulmonary vasoconstriction (HPV). In patients with inflammation like sepsis or ARDS, HPV is impaired, resulting in a ventilation-perfusion mismatch and hypoxia. Since increase of vascular KATP channel Kir6.1 has been reported in animal models of endotoxemia, we studied the expression and physiological effects of Kir6.1 in murine endotoxemic lungs. We hypothesized that inhibition of overexpressed Kir6...
February 13, 2018: Respiratory Research
https://www.readbyqxmd.com/read/29425776/the-effects-of-hemoglobin-glutamer-200-and-ino-on-pulmonary-vascular-tone-and-arterial-oxygenation-in-an-experimental-acute-respiratory-distress-syndrome
#11
Maria Theresa Voelker, Andreas Bergmann, Thilo Busch, Nora Jahn, Sven Laudi, Katharina Noreikat, Philipp Simon, Sven Bercker
INTRODUCTION: Hemoglobin-based oxygen carriers (HBOC) have been developed as an alternative to blood transfusions. Their nitric-oxide-scavenging properties HBOC also induce vasoconstriction. In acute lung injury, an excess of nitric oxide results in a general vasodilation, reducing oxygenation by impairing the hypoxic pulmonary vasoconstriction. Inhaled nitric oxide (iNO) is used to correct the ventilation perfusion mismatch. We hypothesized that the additional use of HBOC might increase this effect...
February 6, 2018: Pulmonary Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/29419444/impact-of-the-mitochondria-targeted-antioxidant-mitoq-on-hypoxia-induced-pulmonary-hypertension
#12
Oleg Pak, Susan Scheibe, Azadeh Esfandiary, Mareike Gierhardt, Akylbek Sydykov, Angela Logan, Athanasios Fysikopoulos, Florian Veit, Matthias Hecker, Florian Kroschel, Karin Quanz, Alexandra Erb, Katharina Schäfer, Mirja Fassbinder, Nasim Alebrahimdehkordi, Hossein A Ghofrani, Ralph T Schermuly, Ralf P Brandes, Werner Seeger, Michael P Murphy, Norbert Weissmann, Natascha Sommer
Increased mitochondrial reactive oxygen species (ROS), particularly superoxide have been suggested to mediate hypoxic pulmonary vasoconstriction (HPV), chronic hypoxia-induced pulmonary hypertension (PH) and right ventricular (RV) remodelling.We determined ROS in acute, chronic hypoxia and investigated the effect of the mitochondria-targeted antioxidant MitoQ under these conditions.The effect of MitoQ or its inactive carrier substance, decyltriphenylphosphonium (TPP+ ), on acute HPV (1% O2 for 10 minutes) was investigated in isolated blood-free perfused mouse lungs...
February 1, 2018: European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology
https://www.readbyqxmd.com/read/29388468/plc%C3%AE-1-pkc%C3%AE%C2%B5-ip3r1-plays-an-important-role-in-hypoxia-induced-calcium-response-in-pulmonary-artery-smooth-muscle-cells
#13
Vishal R Yadav, Tengyao Song, Lin Mei, Leroy Joseph, Yun-Min Zheng, Yong-Xiao Wang
Hypoxia-induced pulmonary vasoconstriction (HPV) is attributed to an increase in intracellular Ca2+ concentration ([Ca2+]i) in pulmonary artery smooth muscle cells (PASMCs). We have reported that phospholipase C-γ1 (PLCγ1) plays a significant role in the hypoxia-induced increase in [Ca2+]i in PASMCs and attendant HPV. In this study, we intended to determine molecular mechanisms for hypoxic Ca2+ and contractile responses in PASMCs. Our data reveal that hypoxic vasoconstriction occurs in PAs, but not in mesenteric arteries (MAs)...
February 1, 2018: American Journal of Physiology. Lung Cellular and Molecular Physiology
https://www.readbyqxmd.com/read/29383676/regulation-signalling-and-functions-of-hormonal-peptides-in-pulmonary-vascular-remodelling-during-hypoxia
#14
REVIEW
Priya Gaur, Supriya Saini, Praveen Vats, Bhuvnesh Kumar
Hypoxic state affects organism primarily by decreasing the amount of oxygen reaching the cells and tissues. To adjust with changing environment organism undergoes mechanisms which are necessary for acclimatization to hypoxic stress. Pulmonary vascular remodelling is one such mechanism controlled by hormonal peptides present in blood circulation for acclimatization. Activation of peptides regulates constriction and relaxation of blood vessels of pulmonary and systemic circulation. Thus, understanding of vascular tone maintenance and hypoxic pulmonary vasoconstriction like pathophysiological condition during hypoxia is of prime importance...
January 30, 2018: Endocrine
https://www.readbyqxmd.com/read/29373219/cutaneous-vascular-responses-of-the-hands-and-feet-to-cooling-rewarming-and-hypoxia-in-humans
#15
Heather C Massey, James R House, Michael J Tipton
INTRODUCTION: This study investigated skin vasomotor responses in the fingers and toes during cooling and rewarming with and without normobaric hypoxia. METHODS: Fourteen volunteers (8 males and 6 females) were exposed to gradual air cooling (mean±SD: -0.4±0.1o C·min-1 ) followed by rewarming (+0.5±0.1o C·min-1 ) while breathing normoxic air (FI O2 0.21 at 761±3 mm Hg) or hypoxic gas (FI O2 0.12, at 761±3 mm Hg, equivalent to ~5000 m above sea level). Throughout the gradual cooling and rewarming phases, rectal temperature was measured, and skin temperatures and laser Doppler skin blood flow were measured on the thumb, little finger, and great and little toe pads...
March 2018: Wilderness & Environmental Medicine
https://www.readbyqxmd.com/read/29364918/riociguat-versus-sildenafil-on-hypoxic-pulmonary-vasoconstriction-and-ventilation-perfusion-matching
#16
COMPARATIVE STUDY
Virginia Chamorro, Daniel Morales-Cano, Javier Milara, Bianca Barreira, Laura Moreno, María Callejo, Gema Mondejar-Parreño, Sergio Esquivel-Ruiz, Julio Cortijo, Ángel Cogolludo, Joan A Barberá, Francisco Perez-Vizcaino
INTRODUCTION: Current treatment with vasodilators for pulmonary hypertension associated with respiratory diseases is limited by their inhibitory effect on hypoxic pulmonary vasoconstriction (HPV) and uncoupling effects on ventilation-perfusion (V'/Q'). Hypoxia is also a well-known modulator of the nitric oxide (NO) pathway, and may therefore differentially affect the responses to phosphodiesterase 5 (PDE5) inhibitors and soluble guanylyl cyclase (sGC) stimulators. So far, the effects of the sGC stimulator riociguat on HPV have been poorly characterized...
2018: PloS One
https://www.readbyqxmd.com/read/29363240/magnesium-attenuates-endothelin-1-induced-vasoreactivity-and-enhances-vasodilatation-in-mouse-pulmonary-arteries-modulation-by-chronic-hypoxic-pulmonary-hypertension
#17
Yun-Ping Mu, Qiu-Hong Huang, Jie-Ling Zhu, Si-Yi Zheng, Fu-Rong Yan, Xiao-Ling Zhuang, James S K Sham, Mo-Jun Lin
NEW FINDINGS: What is the central question of this study? The central goal of this study was to elucidate the role of magnesium in the regulation of pulmonary vascular reactivity in relationship to hypoxic pulmonary hypertension. What is the main finding and its importance? We found that magnesium is essential for normal vasoreactivity of the pulmonary artery. Increasing the magnesium concentration attenuates vasoconstriction and improves vasodilatation via release of nitric oxide. Pulmonary hypertension is associated with endothelial dysfunction resulting in the suppression of magnesium modulation of vasodilatation...
April 1, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29334406/dasatinib-induced-pulmonary-arterial-hypertension
#18
REVIEW
Nurgül Özgür Yurttaş, Ahmet Emre Eşkazan
Drug-induced (group 1) pulmonary hypertension (PH) is an important subgroup of PH involving dasatinib as a likely related agent, which is a second-generation tyrosine kinase inhibitor (TKI) used in the treatment of chronic myeloid leukaemia (CML). The mechanism of dasatinib-induced pulmonary arterial hypertension (PAH) is unclear. However, the occurrence of PAH with late onset in CML patients suggests a chronic pathological mechanism with an insidious onset rather than an acute inflammatory or cardiac aetiology...
January 15, 2018: British Journal of Clinical Pharmacology
https://www.readbyqxmd.com/read/29330945/cyclosporine-a-induces-endothelin-converting-enzyme-1-studies-in-vivo-and-in-vitro
#19
S N Heyman, Z Abassi, C Rosenberger, H Yaseen, G Skarjinski, A Shina, S Mathia, N Krits, M Khamaisi
AIM: Cyclosporine A (CsA) induces renal vasoconstriction and hypoxia and enhances the expression of endothelin-1 (ET-1) pro-hormone (pre-pro-ET-1), plausibly leading to a feed-forward loop of renal vasoconstriction, hypoxia and enhanced synthesis of the potent vasoconstrictor ET-1. Endothelin-converting enzyme (ECE)-1 cleaves big endothelin to generate endothelin (ET)-1 and is upregulated by hypoxia via hypoxia-inducible factor (HIF). We hypothesized that in addition to the direct induction of ET-1 synthesis, CsA might also intensify renal ECE-1 expression, thus contributing to enhanced ET-1 synthesis following CsA...
May 2018: Acta Physiologica
https://www.readbyqxmd.com/read/29301601/role-of-ros-kv-hif-axis-in-the-development-of-hypoxia-induced-pulmonary-hypertension
#20
Wen Wu, Yan Li, Dun-Quan Xu
Hypoxic pulmonary hypertension (HPH) is a common complication in patients with chronic obstructive pulmonary disease (COPD), sleep-disordered breathing, or dwellers in high altitude. The exact mechanisms underlying the development of HPH still remain unclear. Reactive oxygen species (ROS), hypoxia inducible factors (HIF), and potassium channels (KV ) are believed as the main factors during the development of HPH. We propose that the "ROS/Kv/HIF axis" may play an important initiating role in the development of HPH...
December 30, 2017: Chinese Medical Sciences Journal, Chung-kuo i Hsüeh K'o Hsüeh Tsa Chih
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