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Xinliang Z, Achkasov EE, Gavrikov LK, Yuchen L, Zhang C, Dudnik EN, Rumyantseva O, Beeraka NM, Glazachev OS. Assessing the importance and safety of hypoxia conditioning for patients with occupational pulmonary diseases: A recent clinical perspective. Biomed Pharmacother 2024; 178:117275. [PMID: 39126774 DOI: 10.1016/j.biopha.2024.117275] [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: 05/17/2024] [Revised: 07/25/2024] [Accepted: 08/05/2024] [Indexed: 08/12/2024] Open
Abstract
Occupational pulmonary diseases (OPDs) pose a significant global health challenge, contributing to high mortality rates. This review delves into the pathophysiology of hypoxia and the safety of intermittent hypoxic conditioning (IHC) in OPD patients. By examining sources such as PubMed, Relemed, NLM, Scopus, and Google Scholar, the review evaluates the efficacy of IHC in clinical outcomes for OPD patients. It highlights the complexities of cardiovascular and respiratory regulation dysfunctions in OPDs, focusing on respiratory control abnormalities and the impact of intermittent hypoxic exposures. Key areas include the physiological effects of hypoxia, the role of hypoxia-inducible factor-1 alpha (HIF-1α) in occupational lung diseases, and the links between brain ischemia, stroke, and OPDs. The review also explores the interaction between intermittent hypoxic exposures, mitochondrial energetics, and lung physiology. The potential of IHE to improve clinical manifestations and underlying pathophysiology in OPD patients is thoroughly examined. This comprehensive analysis aims to benefit molecular pathologists, pulmonologists, clinicians, and physicians by enhancing understanding of IHE's clinical benefits, from research to patient care, and improving clinical outcomes for OPD patients.
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Affiliation(s)
- Zhang Xinliang
- Chair of Sports Medicine and Rehabilitation, Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia; Co-Chair of Normal Physiology, Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia.
| | - Eugeny E Achkasov
- Chair of Sports Medicine and Rehabilitation, Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia.
| | - Leonid K Gavrikov
- Volgograd State Medical University, 1, Pavshikh Bortsov Sq., Volgograd 400131, Russia.
| | - Li Yuchen
- Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia.
| | - Chen Zhang
- Chair of Epidemiology and Modern Technologies of Vaccination, Institute of Professional Education, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia
| | - Elena N Dudnik
- Co-Chair of Normal Physiology, Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia.
| | - Olga Rumyantseva
- Izmerov Research Institute of Occupational Health, 31 Budeynniy Avenye, Moscow 105275, Russia.
| | - Narasimha M Beeraka
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, 1044 W. Walnut Street, R4-168, Indianapolis, IN 46202, USA; Department of Human Anatomy and Histology, I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia; Raghavendra Institute of Pharmaceutical Education and Research (RIPER), Chiyyedu, Anantapuramu, Andhra Pradesh 515721, India.
| | - Oleg S Glazachev
- Co-Chair of Normal Physiology, Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Trubetskaya Str., Moscow 119991, Russia.
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Arias-Reyes C, Laouafa S, Zubieta-DeUrioste N, Joseph V, Bairam A, Schneider Gasser EM, Soliz J. Erythropoietin Produces a Dual Effect on Carotid Body Chemoreception in Male Rats. Front Pharmacol 2021; 12:727326. [PMID: 34594222 PMCID: PMC8476757 DOI: 10.3389/fphar.2021.727326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/25/2021] [Indexed: 11/13/2022] Open
Abstract
Erythropoietin (EPO) regulates respiration under conditions of normoxia and hypoxia through interaction with the respiratory centers of the brainstem. Here we investigate the dose-dependent impact of EPO in the CB response to hypoxia and hypercapnia. We show, in isolated "en bloc" carotid body (CB) preparations containing the carotid sinus nerve (CSN) from adult male Sprague Dawley rats, that EPO acts as a stimulator of CSN activity in response to hypoxia at concentrations below 0.5 IU/ml. Under hypercapnic conditions, EPO did not influence the CSN response. EPO concentrations above 0.5 IU/ml decreased the response of the CSN to both hypoxia and hypercapnia, reaching complete inhibition at 2 IU/ml. The inhibitory action of high-dose EPO on the CSN activity might result from an increase in nitric oxide (NO) production. Accordingly, CB preparations were incubated with 2 IU/ml EPO and the unspecific NO synthase inhibitor (L-NAME), or the neuronal-specific NO synthase inhibitor (7NI). Both NO inhibitors fully restored the CSN activity in response to hypoxia and hypercapnia in presence of EPO. Our results show that EPO activates the CB response to hypoxia when its concentration does not exceed the threshold at which NO inhibitors masks EPO's action.
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Affiliation(s)
- Christian Arias-Reyes
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | - Sofien Laouafa
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | | | - Vincent Joseph
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | - Aida Bairam
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | - Edith M Schneider Gasser
- Institute of Veterinary Physiology, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland.,Center for Neuroscience Zurich (ZNZ), Zurich, Switzerland
| | - Jorge Soliz
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada.,High Altitude Pulmonary and Pathology Institute (HAPPI-IPPA), La Paz, Bolivia
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3
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Lee J, Walter MF, Korach KS, Noguchi CT. Erythropoietin reduces fat mass in female mice lacking estrogen receptor alpha. Mol Metab 2020; 45:101142. [PMID: 33309599 PMCID: PMC7809438 DOI: 10.1016/j.molmet.2020.101142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/23/2020] [Accepted: 12/07/2020] [Indexed: 12/17/2022] Open
Abstract
Objective Erythropoietin (EPO), the cytokine required for erythropoiesis, contributes to metabolic regulation of fat mass and glycemic control. EPO treatment in mice on high-fat diets (HFD) improved glucose tolerance and decreased body weight gain via reduced fat mass in males and ovariectomized females. The decreased fat accumulation with EPO treatment during HFD in ovariectomized females was abrogated with estradiol supplementation, providing evidence for estrogen-related gender-specific EPO action in metabolic regulation. In this study, we examined the cross-talk between estrogen mediated through estrogen receptor α (ERα) and EPO for the regulation of glucose metabolism and fat mass accumulation. Methods Wild-type (WT) mice and mouse models with ERα knockout (ERα−/−) and targeted deletion of ERα in adipose tissue (ERαadipoKO) were used to examine EPO treatment during high-fat diet feeding and after diet-induced obesity. Results ERα−/− mice on HFD exhibited increased fat mass and glucose intolerance. EPO treatment on HFD reduced fat accumulation in male WT and ERα−/− mice and female ERα−/− mice but not female WT mice. EPO reduced HFD increase in adipocyte size in WT mice but not in mice with deletion of ERα independent of EPO-stimulated reduction in fat mass. EPO treatment also improved glucose and insulin tolerance significantly greater in female ERα−/− mice and female ERαadipoKO compared with WT controls. Increased metabolic activity by EPO was associated with browning of white adipocytes as shown by reductions in white fat-associated genes and induction of brown fat-specific uncoupling protein 1 (UCP1). Conclusions This study clearly identified the role of estrogen signaling in modifying EPO regulation of glucose metabolism and the sex-differential EPO effect on fat mass regulation. Cross-talk between EPO and estrogen was implicated for metabolic homeostasis and regulation of body mass in female mice. Erythropoietin regulates fat mass in male but not female mice on high-fat diets. Female estrogen receptor alpha deletion restores erythropoietin fat mass regulation. Estrogen receptor alpha deletion increases erythropoietin regulation of glucose tolerance. Erythropoietin reduced white fat-associated genes and increased uncoupling protein 1. Erythropoietin and estrogen cross-talk is implicated for metabolic homeostasis.
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Affiliation(s)
- Jeeyoung Lee
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Mary F Walter
- Clinical Laboratory Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kenneth S Korach
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Constance Tom Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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4
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Dey S, Cui Z, Gavrilova O, Zhang X, Gassmann M, Noguchi CT. Sex-specific brain erythropoietin regulation of mouse metabolism and hypothalamic inflammation. JCI Insight 2020; 5:134061. [PMID: 32078583 DOI: 10.1172/jci.insight.134061] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/12/2020] [Indexed: 12/17/2022] Open
Abstract
The blood hormone erythropoietin (EPO), upon binding to its receptor (EpoR), modulates high-fat diet-induced (HFD-induced) obesity in mice, improves glucose tolerance, and prevents white adipose tissue inflammation. Transgenic mice with constitutive overexpression of human EPO solely in the brain (Tg21) were used to assess the neuroendocrine EPO effect without increasing the hematocrit. Male Tg21 mice resisted HFD-induced weight gain; showed lower serum adrenocorticotropic hormone, corticosterone, and C-reactive protein levels; and prevented myeloid cell recruitment to the hypothalamus compared with WT male mice. HFD-induced hypothalamic inflammation (HI) and microglial activation were higher in male mice, and Tg21 male mice exhibited a lower increase in HI than WT male mice. Physiological EPO function in the brain also showed sexual dimorphism in regulating HFD response. Female estrogen production blocked reduced weight gain and HI. Targeted deletion of EpoR gene expression in neuronal cells worsened HFD-induced glucose intolerance in both male and female mice but increased weight gain and HI in the hypothalamus in male mice only. Both male and female Tg21 mice kept on normal chow and HFD showed significantly improved glycemic control. Our data indicate that cerebral EPO regulates weight gain and HI in a sex-dependent response, distinct from EPO regulation of glycemic control, and independent of erythropoietic EPO response.
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Affiliation(s)
| | | | | | - Xiaojie Zhang
- Laboratory of Animal Sciences Section, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Max Gassmann
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia, Lima, Peru
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5
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Vizcardo-Galindo G, León-Velarde F, Villafuerte FC. High-Altitude Hypoxia Decreases Plasma Erythropoietin Soluble Receptor Concentration in Lowlanders. High Alt Med Biol 2020; 21:92-98. [PMID: 31977247 PMCID: PMC7097675 DOI: 10.1089/ham.2019.0118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background: The soluble form of the erythropoietin (Epo) receptor (sEpoR) is an endogenous antagonist of Epo. Decreasing plasma sEpoR increases free Epo, thereby increasing the availability of the hormone. In humans, short-term intermittent normobaric hypoxia exposure reduces sEpoR concentration in plasma. However, whether similar changes occur during continuous hypoxia, such as during high-altitude exposure with ongoing acclimatization, is yet unknown. Therefore, this study aimed to characterize the time-course concentration profile of sEpoR, and also of Epo, reticulocyte count (RC), and hematocrit in healthy lowlanders during 4 days at high altitude. Methods: Twenty-two men residents at sea level traveled by road (∼7 hours) from Lima to Cerro de Pasco (4340 m) for 72 hours. Oxygen saturation as measured by pulse oximetry (SpO2), heart rate, systolic and diastolic blood pressure, Lake Louise Score, sEpoR, Epo, RC, and hematocrit were evaluated every 12 hours, starting 12 hours before the ascent. Results: Plasma sEpoR decreased by 19% and remained below baseline values throughout high-altitude exposure. In parallel, Epo levels increased during the first hours, reaching a peak at 48 hours, and then progressively decreased until 72 hours. As a result, the Epo-to-sEpoR ratio (Epo/sEpoR) remained significantly elevated compared with baseline values. RC increased linearly until the end of the protocol, and hematocrit only showed a marginal increase. Conclusion: Our results show that high-altitude hypoxia causes a significant and stable reduction of plasma sEpoR concentration within the first 24 hours, whereas plasma Epo constantly decreases after having reached a maximum by 48 hours. This simultaneous change leads to a relatively high Epo/sEpoR after 72 hours at high altitude. The early increase in hematocrit likely relates to hemoconcentration, but the steady increase in RC reflects a sustained erythropoietic drive that will lead to elevate hematocrit to a new steady state after acclimatization.
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Affiliation(s)
- Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Fabiola León-Velarde
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú.,Unidad de Transporte de Oxigeno, Instituto de Investigaciones de la Altura (IIA), Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú.,Unidad de Transporte de Oxigeno, Instituto de Investigaciones de la Altura (IIA), Universidad Peruana Cayetano Heredia, Lima, Perú
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6
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Sex differences in breathing. Comp Biochem Physiol A Mol Integr Physiol 2019; 238:110543. [PMID: 31445081 DOI: 10.1016/j.cbpa.2019.110543] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 01/15/2023]
Abstract
Breathing is a vital behavior that ensures both the adequate supply of oxygen and the elimination of CO2, and it is influenced by many factors. Despite that most of the studies in respiratory physiology rely heavily on male subjects, there is much evidence to suggest that sex is an important factor in the respiratory control system, including the susceptibility for some diseases. These different respiratory responses in males and females may be related to the actions of sex hormones, especially in adulthood. These hormones affect neuromodulatory systems that influence the central medullary rhythm/pontine pattern generator and integrator, sensory inputs to the integrator and motor output to the respiratory muscles. In this article, we will first review the sex dependence on the prevalence of some respiratory-related diseases. Then, we will discuss the role of sex and gonadal hormones in respiratory control under resting conditions and during respiratory challenges, such as hypoxia and hypercapnia, and whether hormonal fluctuations during the estrous/menstrual cycle affect breathing control. We will then discuss the role of the locus coeruleus, a sexually dimorphic CO2/pH-chemosensitive nucleus, on breathing regulation in males and females. Next, we will highlight the studies that exist regarding sex differences in respiratory control during development. Finally, the few existing studies regarding the influence of sex on breathing control in non-mammalian vertebrates will be discussed.
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7
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Jeton F, Soliz J, Marchant D, Joseph V, Richalet JP, Pichon A, Voituron N. Increased ventilation in female erythropoietin-deficient mouse line is not progesterone and estrous stage-dependent. Respir Physiol Neurobiol 2017; 245:98-104. [PMID: 28735074 DOI: 10.1016/j.resp.2017.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/05/2017] [Indexed: 01/21/2023]
Abstract
Previous studies suggest that chronic erythropoietin (Epo) deficiency in male mice does not alter normoxic/hypoxic ventilation. As effects of Epo are sex specific and as progesterone could be a respiratory stimulant, we evaluated the impact of Epo deficiency and its possible interaction with progesterone in ventilatory control in female mice during estrous cycle phases. Compared to wild type (WT) animals, Epo-TAgh female mice exhibited higher ventilation in hypoxia. However, when data were separated into luteal and follicular phases of the estrous cycle, basal ventilation and hypoxic ventilation were not different in both mice strains. As progesterone is known to be a potent respiratory stimulant, additional experiments were performed to elucidate its role. Interestingly, after mifepristone treatment, HVR was not modified in WT and Epo-TAgh mice, showing that the ventilatory stimulation observed in females was not directly mediated by progesterone. We conclude that Epo-TAgh female mice show no estrous stage-dependent increase of ventilatory control and progesterone independent response to hypoxia.
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Affiliation(s)
- Florine Jeton
- Université Paris 13, Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, EA 2363, 93017 Bobigny, France; Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, France
| | - Jorge Soliz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
| | - Dominique Marchant
- Université Paris 13, Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, EA 2363, 93017 Bobigny, France
| | - Vincent Joseph
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
| | - Jean-Paul Richalet
- Université Paris 13, Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, EA 2363, 93017 Bobigny, France; Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, France
| | - Aurélien Pichon
- Université Paris 13, Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, EA 2363, 93017 Bobigny, France; Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, France
| | - Nicolas Voituron
- Université Paris 13, Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, EA 2363, 93017 Bobigny, France; Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, France.
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8
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Zhang Y, Rogers HM, Zhang X, Noguchi CT. Sex difference in mouse metabolic response to erythropoietin. FASEB J 2017; 31:2661-2673. [PMID: 28283542 DOI: 10.1096/fj.201601223rrr] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/21/2017] [Indexed: 11/11/2022]
Abstract
Erythropoietin (EPO) is the cytokine that regulates red blood cell production. Less understood is the nonerythroid action of EPO, including metabolic regulation of fat accumulation and glucose homeostasis. Although EPO treatment increased hematocrit and improved glucose tolerance in male and female mice, we observed a gender difference in EPO effects in weight control. EPO treatment reduced diet-induced weight gain from 9.6 ± 1.5 to 4.2 ± 1.4 g in male mice (P < 0.001), while the weight gain in female mice was similar (4.7 ± 2.0 g with PBS treatment and 3.3 ± 2.1 g with EPO treatment). EPO treatment also reduced weight gain in ovariectomized female mice, while the effect was abrogated with estradiol supplementation, suggesting that the sex-differential response to EPO was associated with estrogen. Furthermore, mice with targeted deletion of EPO receptor in white adipose tissue exhibited sex-differential phenotype in weight control and glucose sensitivity, and EPO receptor gene expression was reduced in wild-type female mice, suggesting that white adipose tissue plays an integral role in mediating the metabolic effects of EPO. Our data provide evidence for a sex-differential response to EPO in weight control in mice and underscore the potential for gender specific EPO action beyond erythropoiesis.-Zhang, Y., Rogers, H. M., Zhang, X., Noguchi, C. T. Sex difference in mouse metabolic response to erythropoietin.
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Affiliation(s)
- Yuanyuan Zhang
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Heather M Rogers
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Xiaojie Zhang
- Laboratory of Animal Sciences Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Constance Tom Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA;
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9
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Boukari R, Rossignol O, Baldy C, Marcouiller F, Bairam A, Joseph V. Membrane progesterone receptor-β, but not -α, in dorsal brain stem establishes sex-specific chemoreflex responses and reduces apnea frequency in adult mice. J Appl Physiol (1985) 2016; 121:781-791. [DOI: 10.1152/japplphysiol.00397.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/22/2016] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that membrane progesterone receptors (mPR) contribute to respiratory control in adult male and female mice. Mice were implanted with osmotic minipumps for continuous infusion of small interfering RNA (siRNA) directed against mPRα, mPRβ, or a control solution in the fourth ventricle (to target brain stem respiratory areas) for 14 days. We then performed respiratory and metabolic recordings by whole body plethysmography at rest and in response to hypoxia (12% O2) or hypercapnia (5% CO2, 5 min each). For each treatment, we have verified with immunohistochemistry that the staining intensity of mPRα or mPRβ in the brain stem is decreased. At rest, the siRNA against mPRα and mPRβ increased respiratory frequency in males only. The siRNA against mPRβ almost tripled the frequency of apneas in male and in female mice, while the siRNA against mPRα had no effect. Regarding respiratory chemoreflex, the siRNA against mPRβ suppressed the response to hypoxia in male and female mice and reduced by ∼50% the response to hypercapnia, while the siRNA against mPRα had more limited effects. Interestingly, control females had higher ventilatory response to hypoxia and hypercapnia than males, and these sex-specific effects were suppressed by the siRNA against mPRβ, whereas they were still present after treatment with the siRNA against mPRα. We conclude that mPRβ reduces apnea frequency in male and female mice and establishes sex-specific ventilatory chemoreflex.
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Affiliation(s)
- Ryma Boukari
- Unité de Recherche en Périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Orlane Rossignol
- Unité de Recherche en Périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Cécile Baldy
- Unité de Recherche en Périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - François Marcouiller
- Unité de Recherche en Périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Aida Bairam
- Unité de Recherche en Périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Vincent Joseph
- Unité de Recherche en Périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
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10
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Gassmann M, Muckenthaler MU. Adaptation of iron requirement to hypoxic conditions at high altitude. J Appl Physiol (1985) 2015; 119:1432-40. [PMID: 26183475 DOI: 10.1152/japplphysiol.00248.2015] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/10/2015] [Indexed: 12/12/2022] Open
Abstract
Adequate acclimatization time to enable adjustment to hypoxic conditions is one of the most important aspects for mountaineers ascending to high altitude. Accordingly, most reviews emphasize mechanisms that cope with reduced oxygen supply. However, during sojourns to high altitude adjustment to elevated iron demand is equally critical. Thus in this review we focus on the interaction between oxygen and iron homeostasis. We review the role of iron 1) in the oxygen sensing process and erythropoietin (Epo) synthesis, 2) in gene expression control mediated by the hypoxia-inducible factor-2 (HIF-2), and 3) as an oxygen carrier in hemoglobin, myoglobin, and cytochromes. The blood hormone Epo that is abundantly expressed by the kidney under hypoxic conditions stimulates erythropoiesis in the bone marrow, a process requiring high iron levels. To ensure that sufficient iron is provided, Epo-controlled erythroferrone that is expressed in erythroid precursor cells acts in the liver to reduce expression of the iron hormone hepcidin. Consequently, suppression of hepcidin allows for elevated iron release from storage organs and enhanced absorption of dietary iron by enterocytes. As recently observed in sojourners at high altitude, however, iron uptake may be hampered by reduced appetite and gastrointestinal bleeding. Reduced iron availability, as observed in a hypoxic mountaineer, enhances hypoxia-induced pulmonary hypertension and may contribute to other hypoxia-related diseases. Overall, adequate systemic iron availability is an important prerequisite to adjust to high-altitude hypoxia and may have additional implications for disease-related hypoxic conditions.
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Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, and Universidad Peruana Cayetano Heredia, Lima, Peru; and
| | - Martina U Muckenthaler
- Pediatric Oncology, Hematology and Immunology, University Hospital Heidelberg, Molecular Medicine Partnership Unit, University of Heidelberg, Translational Lung Research Center Heidelberg, and German Center for Lung Research, Heidelberg, Germany
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11
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Caravagna C, Schneider Gasser EM, Ballot O, Joseph V, Soliz J. Chronic overexpression of cerebral Epo improves the ventilatory response to acute hypoxia during the postnatal development. Int J Dev Neurosci 2015; 44:84-91. [DOI: 10.1016/j.ijdevneu.2015.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 06/01/2015] [Accepted: 06/04/2015] [Indexed: 10/23/2022] Open
Affiliation(s)
- Céline Caravagna
- Department of PediatricsLaval University Center de Recherche du Center Hospitalier Universitaire (CHU) de Québec, Hôpital St‐François d'Assise10 Rue de l'EspinayQuébecQCG1L 3L5Canada
| | - Edith M. Schneider Gasser
- Institute of Veterinary PhysiologyVetsuisse‐Faculty University of ZurichWinterthurerstrasse 260CH‐8057ZurichSwitzerland
| | - Orlane Ballot
- Department of PediatricsLaval University Center de Recherche du Center Hospitalier Universitaire (CHU) de Québec, Hôpital St‐François d'Assise10 Rue de l'EspinayQuébecQCG1L 3L5Canada
| | - Vincent Joseph
- Department of PediatricsLaval University Center de Recherche du Center Hospitalier Universitaire (CHU) de Québec, Hôpital St‐François d'Assise10 Rue de l'EspinayQuébecQCG1L 3L5Canada
| | - Jorge Soliz
- Department of PediatricsLaval University Center de Recherche du Center Hospitalier Universitaire (CHU) de Québec, Hôpital St‐François d'Assise10 Rue de l'EspinayQuébecQCG1L 3L5Canada
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Prieto-Lloret J, Ramirez M, Olea E, Moral-Sanz J, Cogolludo A, Castañeda J, Yubero S, Agapito T, Gomez-Niño A, Rocher A, Rigual R, Obeso A, Perez-Vizcaino F, González C. Hypoxic pulmonary vasoconstriction, carotid body function and erythropoietin production in adult rats perinatally exposed to hyperoxia. J Physiol 2015; 593:2459-77. [PMID: 25833164 DOI: 10.1113/jp270274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/31/2015] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Adult animals that have been perinatally exposed to oxygen-rich atmospheres (hyperoxia), recalling those used for oxygen therapy in infants, exhibit a loss of hypoxic pulmonary vasoconstriction, whereas vasoconstriction elicited by depolarizing agents is maintained. Loss of pulmonary hypoxic vasoconstriction is not linked to alterations in oxygen-sensitive K(+) currents in pulmonary artery smooth muscle cells. Loss of hypoxic vasoconstriction is associated with early postnatal oxidative damage and corrected by an antioxidant diet. Perinatal hyperoxia damages carotid body chemoreceptor cell function and the antioxidant diet does not reverse it. The hypoxia-elicited increase in erythropoietin plasma levels is not affected by perinatal hyperoxia. The potential clinical significance of the findings in clinical situations such as pneumonia, chronic obstructive pulmonary disease or general anaesthesia is considered. ABSTRACT Adult mammalians possess three cell systems that are activated by acute bodily hypoxia: pulmonary artery smooth muscle cells (PASMC), carotid body chemoreceptor cells (CBCC) and erythropoietin (EPO)-producing cells. In rats, chronic perinatal hyperoxia causes permanent carotid body (CB) atrophy and functional alterations of surviving CBCC. There are no studies on PASMC or EPO-producing cells. Our aim is to define possible long-lasting functional changes in PASMC or EPO-producing cells (measured as EPO plasma levels) and, further, to analyse CBCC functional alterations. We used 3- to 4-month-old rats born and reared in a normal atmosphere or exposed to perinatal hyperoxia (55-60% O2 for the last 5-6 days of pregnancy and 4 weeks after birth). Perinatal hyperoxia causes an almost complete loss of hypoxic pulmonary vasoconstriction (HPV), which was correlated with lung oxidative status in early postnatal life and prevented by antioxidant supplementation in the diet. O2 -sensitivity of K(+) currents in the PASMC of hyperoxic animals is normal, indicating that their inhibition is not sufficient to trigger HPV. Perinatal hyperoxia also abrogated responses elicited by hypoxia on catecholamine and cAMP metabolism in the CB. An increase in EPO plasma levels elicited by hypoxia was identical in hyperoxic and control animals, implying a normal functioning of EPO-producing cells. The loss of HPV observed in adult rats and caused by perinatal hyperoxia, comparable to oxygen therapy in premature infants, might represent a previously unrecognized complication of such a medical intervention capable of aggravating medical conditions such as regional pneumonias, atelectases or general anaesthesia in adult life.
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Affiliation(s)
- Jesus Prieto-Lloret
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Maria Ramirez
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Elena Olea
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Javier Moral-Sanz
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Facultad de Medicina, CIBER de Enfermedades Respiratorias/Instituto de Salud CIII, Valladolid, Spain
| | - Angel Cogolludo
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Facultad de Medicina, CIBER de Enfermedades Respiratorias/Instituto de Salud CIII, Valladolid, Spain
| | - Javier Castañeda
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Sara Yubero
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Teresa Agapito
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Angela Gomez-Niño
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Asuncion Rocher
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Ricardo Rigual
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Ana Obeso
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
| | - Francisco Perez-Vizcaino
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Facultad de Medicina, CIBER de Enfermedades Respiratorias/Instituto de Salud CIII, Valladolid, Spain
| | - Constancio González
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas
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13
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Ballot O, Joseph V, Soliz J. Endogenous brain erythropoietin is a potent sex-specific respiratory stimulant in adult and newborn mice. J Appl Physiol (1985) 2015; 118:1386-95. [PMID: 25792712 DOI: 10.1152/japplphysiol.00143.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 03/17/2015] [Indexed: 12/31/2022] Open
Abstract
We tested the hypothesis that endogenous brain Epo is a respiratory stimulant. Adult (3 mo) and newborn (10 days) male and female mice received an intracisternal (cisterna magna) injection of soluble Epo receptor (sEpoR; competes with EpoR to bind Epo; 50 μg/ml) or vehicle (0.1% BSA in PBS). Twenty-four hours after injection, we used whole body plethysmography to record minute ventilation (V̇e) tidal volume (VT), respiratory frequency (fR), O2 consumption (V̇o2), and CO2 production (V̇co2) under normoxia and progressive exposure to hypoxia (12-10-6% O2; 10 min each). In adult male and female mice sEpoR decreased normoxic V̇e (-25%), due to a decrease of VT in males and fR in females. Moreover, sEpoR injection decreased the ventilatory response to 12% O2, assessed as V̇e/V̇o2 or V̇e/V̇co2, in male but not in female mice. In newborn male and female mice sEpoR decreased V̇e (-37% in males, -59% in females) and VT (-38% in males, -47% in females) in normoxia and fR in females. During hypoxia, sEpoR decreased V̇e/V̇o2 and V̇e/V̇co2 in mice of both sexes. Upon extreme hypoxia (6% O2), the newborn mice treated with sEpoR showed respiratory depression, signs of asphyxia (gasping) and a high mortality rate in males and females. We concluded that endogenous brain Epo is a potent respiratory stimulant under normoxia and hypoxia in adult and newborn mice. Because sex-specific effects are different in newborn male and female, sex steroids secreted at different ages mice appear to modulate the effects of Epo on respiratory regulation in normoxia and in response to hypoxia.
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Affiliation(s)
- Orlane Ballot
- Centre de Recherche du CHU de Québec, Pavillon St François d'Assise, Département de Pédiatrie, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
| | - Vincent Joseph
- Centre de Recherche du CHU de Québec, Pavillon St François d'Assise, Département de Pédiatrie, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
| | - Jorge Soliz
- Centre de Recherche du CHU de Québec, Pavillon St François d'Assise, Département de Pédiatrie, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
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14
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Affiliation(s)
- J. V. Brugniaux
- Neurovascular Research Laboratory; Faculty of Life Sciences and Education; University of South Wales; Glamorgan UK
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15
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Abstract
There is a growing public awareness that hormones can have a significant impact on most biological systems, including the control of breathing. This review will focus on the actions of two broad classes of hormones on the neuronal control of breathing: sex hormones and stress hormones. The majority of these hormones are steroids; a striking feature is that both groups are derived from cholesterol. Stress hormones also include many peptides which are produced primarily within the paraventricular nucleus of the hypothalamus (PVN) and secreted into the brain or into the circulatory system. In this article we will first review and discuss the role of sex hormones in respiratory control throughout life, emphasizing how natural fluctuations in hormones are reflected in ventilatory metrics and how disruption of their endogenous cycle can predispose to respiratory disease. These effects may be mediated directly by sex hormone receptors or indirectly by neurotransmitter systems. Next, we will discuss the origins of hypothalamic stress hormones and their relationship with the respiratory control system. This relationship is 2-fold: (i) via direct anatomical connections to brainstem respiratory control centers, and (ii) via steroid hormones released from the adrenal gland in response to signals from the pituitary gland. Finally, the impact of stress on the development of neural circuits involved in breathing is evaluated in animal models, and the consequences of early stress on respiratory health and disease is discussed.
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Affiliation(s)
- Mary Behan
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin, USA.
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16
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Guerra-Narbona R, Delgado-García JM, López-Ramos JC. Altitude acclimatization improves submaximal cognitive performance in mice and involves an imbalance of the cholinergic system. J Appl Physiol (1985) 2013; 114:1705-16. [PMID: 23599398 DOI: 10.1152/japplphysiol.01298.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this work was to reveal a hypothetical improvement of cognitive abilities in animals acclimatized to altitude and performing under ground level conditions, when looking at submaximal performance, once seen that it was not possible when looking at maximal scores. We modified contrasted cognitive tasks (object recognition, operant conditioning, eight-arm radial maze, and classical conditioning of the eyeblink reflex), increasing their complexity in an attempt to find performance differences in acclimatized animals vs. untrained controls. In addition, we studied, through immunohistochemical quantification, the expression of choline acetyltransferase and acetyl cholinesterase, enzymes involved in the synthesis and degradation of acetylcholine, in the septal area, piriform and visual cortexes, and the hippocampal CA1 area of animals submitted to acute hypobaric hypoxia, or acclimatized to this simulated altitude, to find a relationship between the cholinergic system and a cognitive improvement due to altitude acclimatization. Results showed subtle improvements of the cognitive capabilities of acclimatized animals in all of the tasks when performed under ground-level conditions (although not before 24 h), in the three tasks used to test explicit memory (object recognition, operant conditioning in the Skinner box, and eight-arm radial maze) and (from the first conditioning session) in the classical conditioning task used to evaluate implicit memory. An imbalance of choline acetyltransferase/acetyl cholinesterase expression was found in acclimatized animals, mainly 24 h after the acclimatization period. In conclusion, altitude acclimatization improves cognitive capabilities, in a process parallel to an imbalance of the cholinergic system.
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Affiliation(s)
- R Guerra-Narbona
- Division of Neuroscience, Pablo de Olavide University, Seville, Spain
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17
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Soliz J. Erythropoietin and respiratory control at adulthood and during early postnatal life. Respir Physiol Neurobiol 2013; 185:87-93. [DOI: 10.1016/j.resp.2012.07.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 01/10/2023]
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18
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Palmer LA, May WJ, deRonde K, Brown-Steinke K, Bates JN, Gaston B, Lewis SJ. Ventilatory responses during and following exposure to a hypoxic challenge in conscious mice deficient or null in S-nitrosoglutathione reductase. Respir Physiol Neurobiol 2012. [PMID: 23183419 DOI: 10.1016/j.resp.2012.11.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exposure to a hypoxic challenge increases ventilation in wild-type (WT) mice that diminish during the challenge (roll-off) whereas return to room air causes an increase in ventilation (short-term facilitation, STF). Since plasma and tissue levels of ventilatory excitant S-nitrosothiols such as S-nitrosoglutathione (GSNO) increase during hypoxia, this study examined whether (1) the initial increase in ventilation is due to generation of GSNO, (2) roll-off is due to increased activity of the GSNO degrading enzyme, GSNO reductase (GSNOR), and (3) STF is limited by GSNOR activity. Initial ventilatory responses to hypoxic challenge (10% O(2), 90% N(2)) were similar in WT, GSNO+/- and GSNO-/- mice. These responses diminished markedly during hypoxic challenge in WT mice whereas there was minimal roll-off in GSNOR+/- and GSNOR-/- mice. Finally, STF was greater in GSNOR+/- and GSNOR-/- mice than in WT mice (especially females). This study suggests that GSNOR degradation of GSNO is a vital step in the expression of ventilatory roll-off and that GSNOR suppresses STF.
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Affiliation(s)
- Lisa A Palmer
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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19
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Palmer LA, May WJ, deRonde K, Brown-Steinke K, Gaston B, Lewis SJ. Hypoxia-induced ventilatory responses in conscious mice: gender differences in ventilatory roll-off and facilitation. Respir Physiol Neurobiol 2012. [PMID: 23183420 DOI: 10.1016/j.resp.2012.11.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this study was to compare the ventilatory responses of C57BL6 female and male mice during a 15 min exposure to a hypoxic-hypercapnic (H-H) or a hypoxic (10% O(2), 90% N(2)) challenge and subsequent return to room air. The ventilatory responses to H-H were similar in males and females whereas there were pronounced gender differences in the ventilatory responses during and following hypoxic challenge. In males, the hypoxic response included initial increases in minute volume via increases in tidal volume and frequency of breathing. These responses declined substantially (roll-off) during hypoxic exposure. Upon return to room-air, relatively sustained increases in these ventilatory parameters (short-term potentiation) were observed. In females, the initial responses to hypoxia were similar to those in males whereas roll-off was greater and post-hypoxia facilitation was smaller than in males. The marked differences in ventilatory roll-off and post-hypoxia facilitation between female and male C57BL6 mice provide evidence that gender is of vital importance to ventilatory control.
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Affiliation(s)
- Lisa A Palmer
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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20
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Radiloff DR, Zhao Y, Boico A, Wu C, Shan S, Palmer G, Hamilton K, Irwin D, Hanna G, Piantadosi CA, Schroeder T. The combination of theophylline and endothelin receptor antagonism improves exercise performance of rats under simulated high altitude. J Appl Physiol (1985) 2012; 113:1243-52. [PMID: 22898548 DOI: 10.1152/japplphysiol.01622.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Decreased physical performance is a well-known consequence of rapid ascent to high altitude. Hypoxic pulmonary vasoconstriction (HPV) potentially limits cardiac output and systemic blood flow, thus preventing successful adaptation to rapid ascent. We hypothesized that pharmacological enhancement of the heart rate with theophylline, combined with reversal of HPV via endothelin blockade, could increase exercise performance at high altitude. Female Sprague-Dawley rats were treated with combinations of 1) theophylline, 2) the endothelin receptor antagonists sitaxsentan/ambrisentan, and/or 3) phosphodiesterase-5 inhibitor sildenafil and exposed to either a simulated high altitude (4,267 m) or 12% oxygen. Exercise capacity, peripheral blood flow, hemodynamics, and pulmonary leak were examined. Combination treatment with theophylline and endothelin blockade, but not with the respective single compounds, significantly prolonged run-to-fatigue time under simulated high altitude. No such efficacy was found when theophylline was combined with sildenafil. Neither theophylline nor sitaxsentan or their combination influenced breathing rates and hemoglobin oxygen saturation. Whereas under hypoxia, theophylline significantly increased muscular blood flow, and sitaxsentan increased tissue oxygenation, the combination improved both parameters but in a reduced manner. Under hypoxia, the combination treatment but not the single compounds significantly enhanced pulmonary arterial pressure compared with controls (13.1 ± 6.3 vs. 11.9 ± 5.2 mmHg), whereas mean arterial pressure remained unaffected. Pulmonary wet-to-dry weight ratios were unaffected by combination treatment. We conclude that concomitant dosing with a cardiac stimulant and endothelin antagonist can partially reverse loss of physical performance capacity under hypobaric hypoxia, independent from improving blood oxygen saturation.
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Affiliation(s)
- Daniel R Radiloff
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
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21
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Cervical spinal erythropoietin induces phrenic motor facilitation via extracellular signal-regulated protein kinase and Akt signaling. J Neurosci 2012; 32:5973-83. [PMID: 22539857 DOI: 10.1523/jneurosci.3873-11.2012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Erythropoietin (EPO) is typically known for its role in erythropoiesis but is also a potent neurotrophic/neuroprotective factor for spinal motor neurons. Another trophic factor regulated by hypoxia-inducible factor-1, vascular endothelial growth factor (VEGF), signals via ERK and Akt activation to elicit long-lasting phrenic motor facilitation (pMF). Because EPO also signals via ERK and Akt activation, we tested the hypothesis that EPO elicits similar pMF. Using retrograde labeling and immunohistochemical techniques, we demonstrate in adult, male, Sprague Dawley rats that EPO and its receptor, EPO-R, are expressed in identified phrenic motor neurons. Intrathecal EPO at C4 elicits long-lasting pMF; integrated phrenic nerve burst amplitude increased >90 min after injection (63 ± 12% baseline 90 min after injection; p < 0.001). EPO increased phosphorylation (and presumed activation) of ERK (1.6-fold vs controls; p < 0.05) in phrenic motor neurons; EPO also increased pAkt (1.6-fold vs controls; p < 0.05). EPO-induced pMF was abolished by the MEK/ERK inhibitor U0126 [1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene] and the phosphatidylinositol 3-kinase/Akt inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one], demonstrating that ERK MAP kinases and Akt are both required for EPO-induced pMF. Pretreatment with U0126 and LY294002 decreased both pERK and pAkt in phrenic motor neurons (p < 0.05), indicating a complex interaction between these kinases. We conclude that EPO elicits spinal plasticity in respiratory motor control. Because EPO expression is hypoxia sensitive, it may play a role in respiratory plasticity in conditions of prolonged or recurrent low oxygen.
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Chambellan A, Coulon S, Cavailles A, Hermine O, Similowski T. BPCO et érythropoïèse : interactions et conséquences. Rev Mal Respir 2012; 29:213-31. [DOI: 10.1016/j.rmr.2011.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 04/21/2011] [Indexed: 11/15/2022]
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van Patot MCT, Gassmann M. Hypoxia: adapting to high altitude by mutating EPAS-1, the gene encoding HIF-2α. High Alt Med Biol 2012; 12:157-67. [PMID: 21718164 DOI: 10.1089/ham.2010.1099] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Living at high altitude is demanding and thus drives adaptational mechanisms. The Tibetan population has had a longer evolutionary period to adapt to high altitude than other mountain populations such as Andeans. As a result, some Tibetans living at high altitudes do not show markedly elevated red blood cell production as compared to South American high altitude natives such as Quechuas or Aymaras, thereby avoiding high blood viscosity creating cardiovascular risk. Unexpectedly, the responsible mutation(s) reducing red blood cell production do not involve either the gene encoding the blood hormone erythropoietin (Epo), or the corresponding regulatory sequences flanking the Epo gene. Similarly, functional mutations in the hypoxia-inducible transcription factor 1α (HIF-1α) gene that represents the oxygen-dependent subunit of the HIF-1 heterodimer, the latter being the main regulator of over 100 hypoxia-inducible genes, have not been described so far. It was not until very recently that three independent groups showed that the gene encoding HIF-2α, EPAS-1 (Wenger et al. 1997), represents a key gene mutated in Tibetan populations adapted to living at high altitudes (Beall et al. 2010 , Yi et al. 2010 , Simonson et al. 2010). Hypoxia-inducible transcription factors were first identified by the description of HIF-1 (Semenza et al. 1991 , 1992), which was subsequently found to enhance transcription of multiple genes that encode proteins necessary for rescuing from hypoxic exposure, including erythropoietic, angiogenic and glycolytic proteins. Then HIF-2 was identified (Ema et al. 1997 ; Flamme et al. 1997 ; Hogenesch et al. 1997 ; and Tian et al. 1997) and although it is highly similar to HIF-1 and has the potential to bind (Camenisch et al. 2001) and mediate (Mole et al. 2009) many of the same genes as HIF-1, its biological actions in response to hypoxia are distinct from those of HIF-1 (reviewed by Loboda et al. 2010). By now, several of these HIF-2 mediated processes have been implicated in the human response to high altitude exposure including erythropoiesis (Kapitsinou et al. 2010), iron homeostasis (Peyssonnaux et al. 2008), metabolism (Shohet et al. 2007; Tormos et al. 2010; Biswas et al. 2010 ; Rankin et al. 2009) and vascular permeability (Chen et al. 2009; Tanaka et al. 2005), among others. Clearly, mutation of EPAS-1 has the potential to bring far more advantage when adapting to high altitude than solely mutating the Epo gene.
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Affiliation(s)
- Martha C Tissot van Patot
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
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Koos BJ. Adenosine A₂a receptors and O₂ sensing in development. Am J Physiol Regul Integr Comp Physiol 2011; 301:R601-22. [PMID: 21677265 DOI: 10.1152/ajpregu.00664.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Reduced mitochondrial oxidative phosphorylation, via activation of adenylate kinase and the resulting exponential rise in the cellular AMP/ATP ratio, appears to be a critical factor underlying O₂ sensing in many chemoreceptive tissues in mammals. The elevated AMP/ATP ratio, in turn, activates key enzymes that are involved in physiologic adjustments that tend to balance ATP supply and demand. An example is the conversion of AMP to adenosine via 5'-nucleotidase and the resulting activation of adenosine A(₂A) receptors, which are involved in acute oxygen sensing by both carotid bodies and the brain. In fetal sheep, A(₂A) receptors associated with carotid bodies trigger hypoxic cardiovascular chemoreflexes, while central A(₂A) receptors mediate hypoxic inhibition of breathing and rapid eye movements. A(₂A) receptors are also involved in hypoxic regulation of fetal endocrine systems, metabolism, and vascular tone. In developing lambs, A(₂A) receptors play virtually no role in O₂ sensing by the carotid bodies, but brain A(₂A) receptors remain critically involved in the roll-off ventilatory response to hypoxia. In adult mammals, A(₂A) receptors have been implicated in O₂ sensing by carotid glomus cells, while central A(₂A) receptors likely blunt hypoxic hyperventilation. In conclusion, A(₂A) receptors are crucially involved in the transduction mechanisms of O₂ sensing in fetal carotid bodies and brains. Postnatally, central A(₂A) receptors remain key mediators of hypoxic respiratory depression, but they are less critical for O₂ sensing in carotid chemoreceptors, particularly in developing lambs.
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Affiliation(s)
- Brian J Koos
- Department of Obstetrics and Gynecology; Brain Research Institute, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA.
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Kopp R, Köblitz L, Egg M, Pelster B. HIF signaling and overall gene expression changes during hypoxia and prolonged exercise differ considerably. Physiol Genomics 2011; 43:506-16. [DOI: 10.1152/physiolgenomics.00250.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Exercise as well as hypoxia cause an increase in angiogenesis, changes in mitochondrial density and alterations in metabolism, but it is still under debate whether the hypoxia inducible factor (HIF) is active during both situations. In this study gene expression analysis of zebrafish larvae that were raised under normoxic, hypoxic, or training conditions were compared, using microarray analysis, quantitative real-time PCR and protein data. Although HIF expression is posttranslationally regulated, mRNA expression levels of all three isoforms ( HIF-1α, HIF-2α, and HIF-3α) differed in each of the experimental groups, but the changes observed in hypoxic animals were much smaller than in trained larvae. Prominent changes were seen for Hif-2α expression, which significantly increased after the first day of exercise and then decreased down to values significantly below control values. HIF-3α mRNA expression in turn increased significantly, and at the end of the training period (9–15 days postfertilization) it was elevated three times. At the protein level a transient increase in HIF-1α was observed in hypoxic larvae, whereas in the exercise group the amount of HIF-1α protein even decreased below the level of control animals. The analyzed transcriptome was more affected in hypoxic zebrafish larvae, and hardly any genes were similarly altered by both treatments. These results clearly showed that HIF proteins played different roles in trained and hypoxic zebrafish larvae and that the exercise-induced transition to a more aerobic phenotype was not achieved by persistent activation of the hypoxic signaling pathway.
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Affiliation(s)
- Renate Kopp
- Institut für Zoologie and Center for Molecular Biosciences, Universität Innsbruck, Innsbruck, Austria
| | - Louise Köblitz
- Institut für Zoologie and Center for Molecular Biosciences, Universität Innsbruck, Innsbruck, Austria
| | - Margit Egg
- Institut für Zoologie and Center for Molecular Biosciences, Universität Innsbruck, Innsbruck, Austria
| | - Bernd Pelster
- Institut für Zoologie and Center for Molecular Biosciences, Universität Innsbruck, Innsbruck, Austria
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Vogtel M, Michels A. Role of intermittent hypoxia in the treatment of bronchial asthma and chronic obstructive pulmonary disease. Curr Opin Allergy Clin Immunol 2010; 10:206-13. [PMID: 20386436 DOI: 10.1097/aci.0b013e32833903a6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE OF REVIEW The purpose of this review is to describe the impact that exposure to intermittent hypoxic training (IHT) could have on bronchial asthma and chronic obstructive pulmonary disease (COPD). This is of particular interest, as an increasing number of patients suffer from severe symptoms of bronchial asthma and COPD and desire more effective and efficient treatment options with fewer side effects. RECENT FINDINGS Exposure to IHT has been shown to raise baroreflex sensitivity to normal levels and to selectively increase hypercapnic ventilatory response, total exercise time, total haemoglobin mass, and lung diffusion capacity for carbon monoxide in COPD patients. However, evidence proving that IHT leads to health benefit effects in bronchial asthma patients has not been produced by recent literature. SUMMARY Recent research outlines the value of IHT as a therapeutic strategy for the treatment of COPD patients, leading to more efficient ventilation. Additionally, IHT might represent an attractive method to complement the known beneficial effects of exercise training and to rebalance early autonomic dysfunction in COPD patients. Future research examining the potential risks and benefits of IHT could pave the way for the development of new therapeutic approaches for patients suffering from bronchial asthma and COPD.
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Affiliation(s)
- Myriam Vogtel
- Institute of Medical Statistics, Informatics and Epidemiology, University Hospital Cologne, Cologne, Germany.
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Current World Literature. Curr Opin Allergy Clin Immunol 2010; 10:267-70. [DOI: 10.1097/aci.0b013e32833aa149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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