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Kermorgant M, Chedmail T, Varenne F, Bareille MP, Beck A, Billette de Villemeur R, Fournié P, Grondin L, Hélissen O, Membrives C, Nasr N, Pavy-Le Traon A, Soler V. Neuro-ophthalmological changes in healthy females exposed to a 5-day dry immersion: a pilot study. NPJ Microgravity 2024; 10:4. [PMID: 38212301 PMCID: PMC10784282 DOI: 10.1038/s41526-024-00344-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 01/01/2024] [Indexed: 01/13/2024] Open
Abstract
After exposure to microgravity, astronauts undergo microgravity-induced thoraco-cephalic fluid shift, which may lead to ocular changes called "spaceflight associated neuro-ocular syndrome" (SANS). The onset of SANS may be multifactorial, including a potential elevation in intracranial pressure. Moreover, little is known about the impact of spaceflight on SANS in women due to the fact that fewer female astronauts have spent time in long-term missions. The objective is to determine whether similar ophthalmological changes occur in healthy women after short-term exposure to microgravity. The auto-refractometer was used to determine objective refraction. The best corrected distance visual acuity was assessed with a Monoyer chart. The ocular axial length was assessed using optical biometry. The applanation tonometry was used to determine intraocular pressure. Peripapillary retinal nerve fibre layer thickness (pRNFLT), macular total retinal thickness, and ganglion cell complex (GCC) were measured using optical coherence tomography. Ocular axial length is reduced after DI. pRNFL is thickest after DI specifically in the temporal, temporal-inferior, and nasal-inferior quadrants. Macular total retinal at the inferior quadrant of the 6-mm ring is thickest after DI. Global GCC is thinnest after DI. In this study, 5 days of DI induces slight but significant ophthalmological changes in women. However, these subtle changes do not correspond to criteria defined in SANS.
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Affiliation(s)
- Marc Kermorgant
- UMR INSERM U1297, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Thibault Chedmail
- Department of Ophthalmology, University Hospital of Toulouse, Toulouse, France
| | - Fanny Varenne
- Department of Ophthalmology, University Hospital of Toulouse, Toulouse, France
| | | | - Arnaud Beck
- Institute for Space Medicine and Physiology (MEDES), Toulouse, France
| | | | - Pierre Fournié
- Department of Ophthalmology, University Hospital of Toulouse, Toulouse, France
| | - Lisa Grondin
- Department of Ophthalmology, University Hospital of Toulouse, Toulouse, France
| | - Ophélie Hélissen
- UMR INSERM U1297, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | | | - Nathalie Nasr
- UMR INSERM U1297, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Neurology, University Hospital of Toulouse, Toulouse, France
| | - Anne Pavy-Le Traon
- UMR INSERM U1297, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France.
- Department of Neurology, University Hospital of Toulouse, Toulouse, France.
| | - Vincent Soler
- Department of Ophthalmology, University Hospital of Toulouse, Toulouse, France.
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Kermorgant M, Nasr N, Czosnyka M, Arvanitis DN, Hélissen O, Senard JM, Pavy-Le Traon A. Impacts of Microgravity Analogs to Spaceflight on Cerebral Autoregulation. Front Physiol 2020; 11:778. [PMID: 32719617 PMCID: PMC7350784 DOI: 10.3389/fphys.2020.00778] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/15/2020] [Indexed: 12/16/2022] Open
Abstract
It is well known that exposure to microgravity in astronauts leads to a plethora physiological responses such as headward fluid shift, body unloading, and cardiovascular deconditioning. When astronauts return to Earth, some encounter problems related to orthostatic intolerance. An impaired cerebral autoregulation (CA), which could be compromised by the effects of microgravity, has been proposed as one of the mechanisms responsible for orthostatic intolerance. CA is a homeostatic mechanism that maintains cerebral blood flow for any variations in cerebral perfusion pressure by adapting the vascular tone and cerebral vessel diameter. The ground-based models of microgravity are useful tools for determining the gravitational impact of spaceflight on human body. The head-down tilt bed rest (HDTBR), where the subject remains in supine position at −6 degrees for periods ranging from few days to several weeks is the most commonly used ground-based model of microgravity for cardiovascular deconditioning. head-down bed rest (HDBR) is able to replicate cephalic fluid shift, immobilization, confinement, and inactivity. Dry immersion (DI) model is another approach where the subject remains immersed in thermoneutral water covered with an elastic waterproof fabric separating the subject from the water. Regarding DI, this analog imitates absence of any supporting structure for the body, centralization of body fluids, immobilization and hypokinesia observed during spaceflight. However, little is known about the impact of microgravity on CA. Here, we review the fundamental principles and the different mechanisms involved in CA. We also consider the different approaches in order to assess CA. Finally, we focus on the effects of short- and long-term spaceflight on CA and compare these findings with two specific analogs to microgravity: HDBR and DI.
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Affiliation(s)
- Marc Kermorgant
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Nathalie Nasr
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France.,Department of Neurology, Institute for Neurosciences, Toulouse University Hospital, Toulouse, France
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge University Hospital, Cambridge, United Kingdom.,Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Dina N Arvanitis
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Ophélie Hélissen
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Jean-Michel Senard
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France.,Department of Clinical Pharmacology, Toulouse University Hospital, Toulouse, France
| | - Anne Pavy-Le Traon
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France.,Department of Neurology, Institute for Neurosciences, Toulouse University Hospital, Toulouse, France
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3
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Borovik AS, Orlova EA, Tomilovskaya ES, Tarasova OS, Vinogradova OL. Phase Coupling Between Baroreflex Oscillations of Blood Pressure and Heart Rate Changes in 21-Day Dry Immersion. Front Physiol 2020; 11:455. [PMID: 32508675 PMCID: PMC7253653 DOI: 10.3389/fphys.2020.00455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/09/2020] [Indexed: 11/13/2022] Open
Abstract
Introduction Dry immersion (DI) is a ground-based experimental model which reproduces the effects of microgravity on the cardiovascular system and, therefore, can be used to study the mechanisms of post-flight orthostatic intolerance in cosmonauts. However, the effects of long-duration DI on cardiovascular system have not been studied yet. The aim of this work was to study the effects of 21-day DI on systemic hemodynamics and its baroreflex control at rest and during head-up tilt test (HUTT). Methods Ten healthy young men were exposed to DI for 21 days. The day before, on the 7th, 14th, and 19th day of DI, as well as on the 1st and 5th days of recovery they were subjected to HUTT: 15 min in supine position and then 15 min of orthostasis (60°). ECG, arterial pressure, stroke volume and respiration rate were continuously recorded during the test. Phase synchronization index (PSI) of beat-to-beat mean arterial pressure (MAP) and heart rate (HR) in the frequency band of baroreflex waves (∼0.1 Hz) was used as a quantitative measure of baroreflex activity. Results During DI, strong tachycardia and the reduction of stroke volume were observed both in supine position and during HUTT, these indicators did not recover on post-immersion day 5. In contrast, systolic arterial pressure and MAP decreased during HUTT on 14th day of DI, but then restored to pre-immersion values. Before DI and on day 5 of recovery, a transition from supine position to orthostasis was accompanied by an increase in PSI at the baroreflex frequency. However, PSI did not change in HUTT performed during DI and on post-immersion day 1. The amplitude of MAP oscillations at this frequency were increased by HUTT at all time points, while an increase of respective HR oscillations was absent during DI. Conclusion 21-day DI drastically changed the hemodynamic response to HUTT, while its effect on blood pressure was reduced between days 14 and 19, which speaks in favor of the adaptation to the conditions of DI. The lack of increase in phase synchronization of baroreflex MAP and HR oscillations during HUTT indicates disorders of baroreflex cardiac control during DI.
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Affiliation(s)
- Anatoly S Borovik
- State Research Center of the Russian Federation, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Evgeniya A Orlova
- State Research Center of the Russian Federation, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Elena S Tomilovskaya
- State Research Center of the Russian Federation, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Olga S Tarasova
- State Research Center of the Russian Federation, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Olga L Vinogradova
- State Research Center of the Russian Federation, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia.,Faculty of Basic Medicine, M.V. Lomonosov Moscow State University, Moscow, Russia
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DI-5-CUFFS: Venoconstrictive Thigh Cuffs Limit Body Fluid Changes but Not Orthostatic Intolerance Induced by a 5-Day Dry Immersion. Front Physiol 2020. [DOI: 10.108810.3389/fphys.2020.00383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Robin A, Auvinet A, Degryse B, Murphy R, Bareille MP, Beck A, Gharib C, Gauquelin-Koch G, Daviet A, Larcher F, Custaud MA, Navasiolava N. DI-5-CUFFS: Venoconstrictive Thigh Cuffs Limit Body Fluid Changes but Not Orthostatic Intolerance Induced by a 5-Day Dry Immersion. Front Physiol 2020; 11:383. [PMID: 32431622 PMCID: PMC7214795 DOI: 10.3389/fphys.2020.00383] [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] [Received: 01/17/2020] [Accepted: 03/30/2020] [Indexed: 12/24/2022] Open
Abstract
Venoconstrictive thigh cuffs are used by cosmonauts to ameliorate symptoms associated with cephalad fluid shift. A ground simulation of microgravity, using the dry immersion (DI) model, was performed to assess the effects of thigh cuffs on body fluid changes and dynamics, as well as on cardiovascular deconditioning. Eighteen healthy men (25-43 years), randomly divided into two groups, (1) control group or (2) group with thigh cuffs worn 10 h/day, underwent 5-day DI. Cardiovascular responses to orthostatic challenge were evaluated using the lower body negative pressure (LBNP) test; body fluid changes were assessed by bio-impedance and hormonal assay; plasma volume evolution was estimated using hemoglobin-hematocrit; subjective tolerance was assessed by questionnaires. DI induced a decrease in plasma volume of 15-20%. Reduction in total body water of 3-6% stabilized toward the third day of DI. This reduction was derived mostly from the extracellular compartment. During the acute phase of DI, thigh cuffs limited the decrease in renin and the increase in N-terminal prohormone of brain natriuretic peptide (NT-proBNP), the loss in total body water, and tended to limit the loss in calf volume, extracellular volume and plasma volume. At the later stable phase of DI, a moderate protective effect of thigh cuffs remained evident on the body fluids. Orthostatic tolerance time dropped after DI without significant difference between groups. Thigh cuff countermeasure slowed down and limited the loss of body water and tended to limit plasma loss induced by DI. These observed physiological responses persisted during periods when thigh cuffs were removed. However, thigh cuffs did not counteract decreased tolerance to orthostatic challenge.
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Affiliation(s)
- Adrien Robin
- Centre de Recherche Clinique, CHU d'Angers, Angers, France.,Mitovasc UMR INSERM 1083-CNRS 6015, Université d'Angers, Angers, France
| | - Aline Auvinet
- Centre de Recherche Clinique, CHU d'Angers, Angers, France
| | - Bernard Degryse
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Ronan Murphy
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | | | | | - Claude Gharib
- Faculté de Médecine Lyon-Est, Institut NeuroMyoGène, Université de Lyon, Lyon, France
| | | | - Aude Daviet
- Laboratoire de Biochimie, CHU d'Angers, Angers, France
| | | | - Marc-Antoine Custaud
- Centre de Recherche Clinique, CHU d'Angers, Angers, France.,Mitovasc UMR INSERM 1083-CNRS 6015, Université d'Angers, Angers, France
| | - Nastassia Navasiolava
- Centre de Recherche Clinique, CHU d'Angers, Angers, France.,Mitovasc UMR INSERM 1083-CNRS 6015, Université d'Angers, Angers, France
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Tomilovskaya E, Shigueva T, Sayenko D, Rukavishnikov I, Kozlovskaya I. Dry Immersion as a Ground-Based Model of Microgravity Physiological Effects. Front Physiol 2019; 10:284. [PMID: 30971938 PMCID: PMC6446883 DOI: 10.3389/fphys.2019.00284] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 03/04/2019] [Indexed: 01/04/2023] Open
Abstract
Dry immersion (DI) is one of the most widely used ground models of microgravity. DI accurately and rapidly reproduces most of physiological effects of short-term space flights. The model simulates such factors of space flight as lack of support, mechanical and axial unloading as well as physical inactivity. The current manuscript gathers the results of physiological studies performed from the time of the model's development. This review describes the changes induced by DI of different duration (from few hours to 56 days) in the neuromuscular, sensory-motor, cardiorespiratory, digestive and excretory, and immune systems, as well as in the metabolism and hemodynamics. DI reproduces practically the full spectrum of changes in the body systems during the exposure to microgravity. The numerous publications from Russian researchers, which until present were mostly inaccessible for scientists from other countries are summarized in this work. These data demonstrated and validated DI as a ground-based model for simulation of physiological effects of weightlessness. The magnitude and rate of physiological changes during DI makes this method advantageous as compared with other ground-based microgravity models. The actual and potential uses of the model are discussed in the context of fundamental studies and applications for Earth medicine.
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Affiliation(s)
- Elena Tomilovskaya
- RF SSC – Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Tatiana Shigueva
- RF SSC – Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Dimitry Sayenko
- Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Ilya Rukavishnikov
- RF SSC – Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Inessa Kozlovskaya
- RF SSC – Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
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7
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Goswami N, Blaber AP, Hinghofer-Szalkay H, Convertino VA. Lower Body Negative Pressure: Physiological Effects, Applications, and Implementation. Physiol Rev 2019; 99:807-851. [PMID: 30540225 DOI: 10.1152/physrev.00006.2018] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This review presents lower body negative pressure (LBNP) as a unique tool to investigate the physiology of integrated systemic compensatory responses to altered hemodynamic patterns during conditions of central hypovolemia in humans. An early review published in Physiological Reviews over 40 yr ago (Wolthuis et al. Physiol Rev 54: 566-595, 1974) focused on the use of LBNP as a tool to study effects of central hypovolemia, while more than a decade ago a review appeared that focused on LBNP as a model of hemorrhagic shock (Cooke et al. J Appl Physiol (1985) 96: 1249-1261, 2004). Since then there has been a great deal of new research that has applied LBNP to investigate complex physiological responses to a variety of challenges including orthostasis, hemorrhage, and other important stressors seen in humans such as microgravity encountered during spaceflight. The LBNP stimulus has provided novel insights into the physiology underlying areas such as intolerance to reduced central blood volume, sex differences concerning blood pressure regulation, autonomic dysfunctions, adaptations to exercise training, and effects of space flight. Furthermore, approaching cardiovascular assessment using prediction models for orthostatic capacity in healthy populations, derived from LBNP tolerance protocols, has provided important insights into the mechanisms of orthostatic hypotension and central hypovolemia, especially in some patient populations as well as in healthy subjects. This review also presents a concise discussion of mathematical modeling regarding compensatory responses induced by LBNP. Given the diverse applications of LBNP, it is to be expected that new and innovative applications of LBNP will be developed to explore the complex physiological mechanisms that underline health and disease.
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Affiliation(s)
- Nandu Goswami
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Andrew Philip Blaber
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Helmut Hinghofer-Szalkay
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Victor A Convertino
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
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Shykoff BE, Florian JP. Pulmonary effects of repeated six-hour normoxic and hyperoxic dives. PLoS One 2018; 13:e0202892. [PMID: 30192774 PMCID: PMC6128531 DOI: 10.1371/journal.pone.0202892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 08/11/2018] [Indexed: 11/19/2022] Open
Abstract
This study examines differential effects of immersion, elevated oxygen partial pressure, and exercise on pulmonary function after series of five daily six-hour dives at 130 kPa (1.3 ATA), with 18 hours between dives. Five cohorts of 10 to 14 divers participated. The exposure phases were resting while breathing O2 or air in the water ("wetO2", "wetAir") or O2 in the hyperbaric chamber ("dryO2"), and exercise in the water while breathing O2 or air ("wetO2X", "wetAirX"). Respiratory symptoms were recorded during and after each dive, and pulmonary function (forced flow-volume) was measured twice at baseline before diving, after each dive both immediately and on the following morning, and three days post diving ("Day+3"). The incidences of symptoms and of flow volume changes from baseline greater than normal limits ("ΔFV") were assessed, as were mean ΔFV. The parameters examined were forced vital capacity (FVC), forced expired volume in 1 second (FEV1), and forced expired flow from 25% to 75% volume expired (FEF25-75). The phases ranked from greatest to least fraction of diver-days with symptoms were wetO2X (56%) > dryO2 (42%) > wetO2 (13%) > [wetAir (2%) or wetAirX (1%)] (p<0.05). FEV1 and FEF25-75 were depressed in the morning following wetO2 and wetO2X and on Day+3 after and wetO2X, but increased immediately following each wetAirX dive. O2 exposures caused symptoms and ΔFV suggestive of pulmonary oxygen toxicity,exacerbated by exercise. Indices of small airway function showed late (17-hour) post-O2 exposure deficits, but, particularly with exercise, improvement was evident early after exposure with or without O2. FEF25-75 and FEV1 remained depressed on Day+3 after wetO2 and wetO2X.
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Affiliation(s)
- Barbara E. Shykoff
- Navy Experimental Diving Unit, Panama City, Florida, United States of America
| | - John P. Florian
- Navy Experimental Diving Unit, Panama City, Florida, United States of America
- * E-mail:
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10
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De Abreu S, Amirova L, Murphy R, Wallace R, Twomey L, Gauquelin-Koch G, Raverot V, Larcher F, Custaud MA, Navasiolava N. Multi-System Deconditioning in 3-Day Dry Immersion without Daily Raise. Front Physiol 2017; 8:799. [PMID: 29081752 PMCID: PMC5645726 DOI: 10.3389/fphys.2017.00799] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/28/2017] [Indexed: 11/30/2022] Open
Abstract
Dry immersion (DI) is a Russian-developed, ground-based model to study the physiological effects of microgravity. It accurately reproduces environmental conditions of weightlessness, such as enhanced physical inactivity, suppression of hydrostatic pressure and supportlessness. We aimed to study the integrative physiological responses to a 3-day strict DI protocol in 12 healthy men, and to assess the extent of multi-system deconditioning. We recorded general clinical data, biological data and evaluated body fluid changes. Cardiovascular deconditioning was evaluated using orthostatic tolerance tests (Lower Body Negative Pressure + tilt and progressive tilt). Metabolic state was tested with oral glucose tolerance test. Muscular deconditioning was assessed via muscle tone measurement. Results: Orthostatic tolerance time dropped from 27 ± 1 to 9 ± 2 min after DI. Significant impairment in glucose tolerance was observed. Net insulin response increased by 72 ± 23% on the third day of DI compared to baseline. Global leg muscle tone was approximately 10% reduced under immersion. Day-night changes in temperature, heart rate and blood pressure were preserved on the third day of DI. Day-night variations of urinary K+ diminished, beginning at the second day of immersion, while 24-h K+ excretion remained stable throughout. Urinary cortisol and melatonin metabolite increased with DI, although within normal limits. A positive correlation was observed between lumbar pain intensity, estimated on the second day of DI, and mean 24-h urinary cortisol under DI. In conclusion, DI represents an accurate and rapid model of gravitational deconditioning. The extent of glucose tolerance impairment may be linked to constant enhanced muscle inactivity. Muscle tone reduction may reflect the reaction of postural muscles to withdrawal of support. Relatively modest increases in cortisol suggest that DI induces a moderate stress effect. In prospect, this advanced ground-based model is extremely suited to test countermeasures for microgravity-induced deconditioning and physical inactivity-related pathologies.
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Affiliation(s)
- Steven De Abreu
- Mitovasc, UMR Institut National de la Santé et de la Recherche Médicale 1083, Centre National de la Recherche Scientifique 6015, Université d'Angers, Angers, France
| | - Liubov Amirova
- Mitovasc, UMR Institut National de la Santé et de la Recherche Médicale 1083, Centre National de la Recherche Scientifique 6015, Université d'Angers, Angers, France.,Russian Federation State Research Center, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Ronan Murphy
- Center for Preventive Medicine, School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Robert Wallace
- Center for Preventive Medicine, School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Laura Twomey
- Center for Preventive Medicine, School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | | | | | - Françoise Larcher
- Laboratoire de Biochimie, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Marc-Antoine Custaud
- Mitovasc, UMR Institut National de la Santé et de la Recherche Médicale 1083, Centre National de la Recherche Scientifique 6015, Université d'Angers, Angers, France.,Centre de Recherche Clinique, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Nastassia Navasiolava
- Centre de Recherche Clinique, Centre Hospitalier Universitaire d'Angers, Angers, France
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11
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Ogoh S, Hirasawa A, de Abreu S, Denise P, Normand H. Internal carotid, external carotid and vertebral artery blood flow responses to 3 days of head-out dry immersion. Exp Physiol 2017; 102:1278-1287. [DOI: 10.1113/ep086507] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/18/2017] [Indexed: 01/23/2023]
Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering; Toyo University; Kawagoe-Shi Saitama Japan
| | - Ai Hirasawa
- Faculty of Health Science, Department of Health and Welfare; Kyorin University; Mitaka-shi Tokyo Japan
| | - Steven de Abreu
- Normandie University, Unicaen; Inserm Comete; Chu Caen France
| | - Pierre Denise
- Normandie University, Unicaen; Inserm Comete; Chu Caen France
| | - Hervé Normand
- Normandie University, Unicaen; Inserm Comete; Chu Caen France
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12
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Linossier MT, Amirova LE, Thomas M, Normand M, Bareille MP, Gauquelin-Koch G, Beck A, Costes-Salon MC, Bonneau C, Gharib C, Custaud MA, Vico L. Effects of short-term dry immersion on bone remodeling markers, insulin and adipokines. PLoS One 2017; 12:e0182970. [PMID: 28806419 PMCID: PMC5555617 DOI: 10.1371/journal.pone.0182970] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/27/2017] [Indexed: 12/21/2022] Open
Abstract
Background Dry immersion (DI), a ground-based model of microgravity previously used in Russia, has been recently implemented in France. The aim of this study was to analyze early events in a short-term DI model in which all conditions are met to investigate who is first challenged from osteo- or adipo-kines and to what extent they are associated to insulin-regulating hormones. Methods Twelve healthy men were submitted to a 3-day DI. Fasting blood was collected during pre-immersion phase for the determination of the baseline data collection (BDC), daily during DI (DI24h, DI48H and DI72h), then after recovery (R+3h and R+24h). Markers of bone turnover, phosphocalcic metabolism, adipokines and associated factors were measured. Results Bone resorption as assessed by tartrate-resistant acid phosphatase isoform 5b and N-terminal crosslinked telopeptide of type I collagen levels increased as early as DI24h. At the same time, total procollagen type I N- and C-terminal propeptides and osteoprotegerin, representing bone formation markers, decreased. Total osteocalcin [OC] was unaffected, but its undercarboxylated form [Glu-OC] increased from DI24h to R+3h. The early and progressive increase in bone alkaline phosphatase activities suggested an increased mineralization. Dickkopf-1 and sclerostin, as negative regulators of the Wnt-β catenin pathway, were unaltered. No change was observed either in phosphocalcic homeostasis (calcium and phosphate serum levels, 25-hydroxyvitamin D, fibroblast growth factor 23 [FGF23]) or in inflammatory response. Adiponectemia was unchanged, whereas circulating leptin concentrations increased. Neutrophil gelatinase-associated lipocalin [lipocalin-2], a potential regulator of bone homeostasis, was found elevated by 16% at R+3h compared to DI24h. The secretory form of nicotinamide phosphoribosyl-transferase [visfatin] concentrations almost doubled after one day of DI and remained elevated. Serum insulin-like growth factor 1 levels progressively increased. Fasting insulin concentrations increased during the entire DI, whereas fasting glucose levels tended to be higher only at DI24h and then returned to BDC values. Changes in bone resorption parameters negatively correlated with changes in bone formation parameters. Percent changes of ultra-sensitive C-reactive protein positively correlated with changes in osteopontin, lipocalin-2 and fasting glucose. Furthermore, a positive correlation was found between changes in FGF23 and Glu-OC, the two main osteoblast-/osteocyte-derived hormones. Conclusion Our results demonstrated that DI induced an unbalanced remodeling activity and the onset of insulin resistance. This metabolic adaptation was concomitant with higher levels of Glu-OC. This finding confirms the role of bone as an endocrine organ in humans. Furthermore, visfatin for which a great responsiveness was observed could represent an early and sensitive marker of unloading in humans.
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Affiliation(s)
- Marie-Thérèse Linossier
- University of Lyon, Medicine Faculty of Saint-Etienne, INSERM, UMR 1059, Saint Etienne, France
- * E-mail:
| | - Liubov E. Amirova
- University of Angers, Medicine Faculty, Mitovasc Laboratory, UMR CNRS 6015, INSERM 1083, Angers, France
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Mireille Thomas
- University of Lyon, Medicine Faculty of Saint-Etienne, INSERM, UMR 1059, Saint Etienne, France
| | - Myriam Normand
- University of Lyon, Medicine Faculty of Saint-Etienne, INSERM, UMR 1059, Saint Etienne, France
| | | | | | - Arnaud Beck
- Institute of Space Physiology and Medicine (MEDES), Toulouse, France
| | | | | | | | - Marc-Antoine Custaud
- University of Angers, Medicine Faculty, Mitovasc Laboratory, UMR CNRS 6015, INSERM 1083, Angers, France
- Clinical Research Center, CHU d'Angers, Angers, France
| | - Laurence Vico
- University of Lyon, Medicine Faculty of Saint-Etienne, INSERM, UMR 1059, Saint Etienne, France
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Florian JP, Chon KH, Faes L, Shykoff BE. Breathing 100% oxygen during water immersion improves postimmersion cardiovascular responses to orthostatic stress. Physiol Rep 2016; 4:4/23/e13031. [PMID: 28604343 PMCID: PMC5260089 DOI: 10.14814/phy2.13031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/15/2016] [Indexed: 12/01/2022] Open
Abstract
Physiological compensation to postural stress is weakened after long‐duration water immersion (WI), thus predisposing individuals to orthostatic intolerance. This study was conducted to compare hemodynamic responses to postural stress following exposure to WI alone (Air WI), hyperbaric oxygen alone in a hyperbaric chamber (O2HC), and WI combined with hyperbaric oxygen (O2WI), all at a depth of 1.35 ATA, and to determine whether hyperbaric oxygen is protective of orthostatic tolerance. Thirty‐two healthy men underwent up to 15 min of 70° head‐up tilt (HUT) testing before and after a single 6‐h resting exposure to Air WI (N = 10), O2 HC (N = 12), or O2WI (N = 10). Heart rate (HR), blood pressure (BP), cardiac output (Q), stroke volume (SV), forearm blood flow (FBF), and systemic and forearm vascular resistance (SVR and FVR) were measured. Although all subjects completed HUT before Air WI, three subjects reached presyncope after Air WI exposure at 10.4, 9.4, and 6.9 min. HUT time did not change after O2WI or O2HC exposures. Compared to preexposure responses, HR increased (+10 and +17%) and systolic BP (−13 and −8%), and SV (−16 and −23%) decreased during HUT after Air WI and O2WI, respectively. In contrast, HR and SV did not change, and systolic (+5%) and diastolic BP (+10%) increased after O2HC. Q decreased (−13 and −7%) and SVR increased (+12 and +20%) after O2WI and O2HC, respectively, whereas SVR decreased (−9%) after Air WI. Opposite patterns were evident following Air WI and O2HC for FBF (−26 and +52%) and FVR (+28 and −30%). Therefore, breathing hyperbaric oxygen during WI may enhance post‐WI cardiovascular compensatory responses to orthostatic stress.
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Affiliation(s)
| | - Ki H Chon
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut
| | - Luca Faes
- Bruno Kessler Foundation, Trento, Italy.,BIOtech, University of Trento, Trento, Italy
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Watenpaugh DE. Analogs of microgravity: head-down tilt and water immersion. J Appl Physiol (1985) 2016; 120:904-14. [DOI: 10.1152/japplphysiol.00986.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/04/2016] [Indexed: 01/26/2023] Open
Abstract
This article briefly reviews the fidelity of ground-based methods used to simulate human existence in weightlessness (spaceflight). These methods include horizontal bed rest (BR), head-down tilt bed rest (HDT), head-out water immersion (WI), and head-out dry immersion (DI; immersion with an impermeable elastic cloth barrier between subject and water). Among these, HDT has become by far the most commonly used method, especially for longer studies. DI is less common but well accepted for long-duration studies. Very few studies exist that attempt to validate a specific simulation mode against actual microgravity. Many fundamental physical, and thus physiological, differences exist between microgravity and our methods to simulate it, and between the different methods. Also, although weightlessness is the salient feature of spaceflight, several ancillary factors of space travel complicate Earth-based simulation. In spite of these discrepancies and complications, the analogs duplicate many responses to 0 G reasonably well. As we learn more about responses to microgravity and spaceflight, investigators will continue to fine-tune simulation methods to optimize accuracy and applicability.
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Affiliation(s)
- Donald E. Watenpaugh
- Department of Integrative Physiology, University of North Texas Health Science Center, Fort Worth, Texas
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Treffel L, Dmitrieva L, Gauquelin-Koch G, Custaud MA, Blanc S, Gharib C, Millet C. Craniomandibular System and Postural Balance after 3-Day Dry Immersion. PLoS One 2016; 11:e0150052. [PMID: 26913867 PMCID: PMC4767814 DOI: 10.1371/journal.pone.0150052] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/09/2016] [Indexed: 12/30/2022] Open
Abstract
The objective of the study was to determine the influence of simulated microgravity by exposure to dry immersion on the craniomandibular system. Twelve healthy male volunteers participated in a 3-day dry immersion study. Before and immediately after exposure we measured maximal bite force using piezoresistive sensors. The mechanical properties of the jaw and cervical muscles were evaluated before, during, and after dry immersion using MyotonPRO. Because recent studies reported the effects of jaw motor activity on the postural stability of humans, stabilometric measurements of center of pressure were performed before and after dry immersion in two mandibular positions: rest position without jaw clenching, and intercuspidal position during voluntary teeth clenching. Results revealed no significant changes of maximal bite force after dry immersion. All postural parameters were significantly altered by dry immersion. There were however no significant differences in stabilometric data according to mandibular position. Moreover the masseter tonicity increased immediately after the end of dry immersion period. Dry immersion could be used as a valid model for studying the effects of microgravity on human subjects. However, 3 days appear insufficient in duration to evaluate the effects of weightlessness on maximal bite force. Our research suggests a link between postural disturbance after dry immersion and masseter tonicity.
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Affiliation(s)
- Loïc Treffel
- Université Claude Bernard Lyon 1, Lyon, France
- Université de Strasbourg, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7178, Strasbourg, France
| | - Liubov Dmitrieva
- Institute of Biomedical Problems, Moscow, Russia
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6214 - Institut National de la Santé et de la Recherche Médicale 1083, Université d’Angers, Angers, France
| | | | - Marc-Antoine Custaud
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6214 - Institut National de la Santé et de la Recherche Médicale 1083, Université d’Angers, Angers, France
- Centre de Recherche Clinique, Centre Hospitalo-Universitaire d’Angers, Angers, France
| | - Stéphane Blanc
- Université de Strasbourg, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7178, Strasbourg, France
| | - Claude Gharib
- Université Claude Bernard Lyon 1, Lyon, France
- Centre International d’Ostéopathie, Saint-Etienne, France
| | - Catherine Millet
- Université Claude Bernard Lyon 1, Lyon, France
- Service d’Odontologie, Hospices Civils de Lyon, Lyon, France
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16
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Adami R, Bottai D. Movement impairment: Focus on the brain. J Neurosci Res 2016; 94:310-7. [DOI: 10.1002/jnr.23711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 12/04/2015] [Accepted: 12/22/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Raffaella Adami
- Department of Health Science; Faculty of Medicine, University of Milan; Milan Italy
| | - Daniele Bottai
- Department of Health Science; Faculty of Medicine, University of Milan; Milan Italy
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Florian JP, Simmons EE, Chon KH, Faes L, Shykoff BE. Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion. J Appl Physiol (1985) 2013; 115:1275-89. [PMID: 23950166 DOI: 10.1152/japplphysiol.00466.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32-33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variability (HRV) frequency-domain variables [low-frequency (LF), high-frequency (HF), and normalized (n)] were measured. Cold pressor test showed lower HR, SBP, SV, Q, calf BF, LFnHRV, and LF/HFHRV and higher CVR and HFnHRV after than before WI (P < 0.05). Handgrip test showed no effect of WI on maximum strength and endurance and lower HR, SBP, SV, Q, and calf BF and higher SVR and CVR after than before WI (P < 0.05). During postexercise muscle ischemia, HFnHRV increased from baseline after WI only, and LFnHRV was lower after than before WI (P < 0.05). HUT test showed lower SBP, DBP, SV, forearm BF, and BRS and higher HR, FVR, LF/HFHRV, and LFnHRV after than before WI (P < 0.05). The changes suggest differential activation/depression during cold pressor and handgrip (reduced sympathetic/elevated parasympathetic) and HUT (elevated sympathetic/reduced parasympathetic) following 6 h of WI.
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18
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Faes L, Masè M, Nollo G, Chon KH, Florian JP. Measuring postural-related changes of spontaneous baroreflex sensitivity after repeated long-duration diving: frequency domain approaches. Auton Neurosci 2013; 178:96-102. [PMID: 23587978 DOI: 10.1016/j.autneu.2013.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 02/28/2013] [Accepted: 03/12/2013] [Indexed: 11/29/2022]
Abstract
Sustained water immersion is thought to modulate orthostatic tolerance to an extent dependent on the duration and repetition over consecutive days of the diving sessions. We tested this hypothesis investigating in ten healthy subjects the potential changes in the cardiovascular response to head-up tilt induced by single and multiple resting air dives. Parametric cross-spectral analysis of spontaneous RR interval and systolic arterial pressure variability was performed in three experimental sessions: before diving (BD), after single 6-hour dive (ASD), and after multiple 6-hour dives (AMD, 5 consecutive days with 18-hour surface interval). From this analysis, baroreflex sensitivity (BRS) was computed as spectral power ratio (αBRS), non-causal transfer function gain (tfBRS) and causal transfer function gain (γBRS) evaluated at low frequency (0.04-0.14Hz) in the supine position (su) as well as in the standing upright position in the early tilt (et) and late tilt (lt) epochs. We found that, while αBRS decreased significantly in et and lt compared to su during all sessions, tfBRS and γBRS decreased during ASD and AMD but not during BD; moreover γBRS evidenced a progressive decrease from BD to ASD and to AMD in both et and lt epochs. These results indicate the necessity of following a causal approach for the estimation of BRS in the frequency domain, and suggest a progressive impairment of the baroreflex response to postural stress after single and multiple dives, which may reflect symptoms of increasing orthostatic intolerance.
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Affiliation(s)
- Luca Faes
- Department Physics and BIOtech Center, University of Trento, Trento, Italy.
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19
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Ryan KL, Rickards CA, Hinojosa-Laborde C, Cooke WH, Convertino VA. Sympathetic responses to central hypovolemia: new insights from microneurographic recordings. Front Physiol 2012; 3:110. [PMID: 22557974 PMCID: PMC3337468 DOI: 10.3389/fphys.2012.00110] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 04/03/2012] [Indexed: 11/13/2022] Open
Abstract
Hemorrhage remains a major cause of mortality following traumatic injury in both military and civilian settings. Lower body negative pressure (LBNP) has been used as an experimental model to study the compensatory phase of hemorrhage in conscious humans, as it elicits central hypovolemia like that induced by hemorrhage. One physiological compensatory mechanism that changes during the course of central hypovolemia induced by both LBNP and hemorrhage is a baroreflex-mediated increase in muscle sympathetic nerve activity (MSNA), as assessed with microneurography. The purpose of this review is to describe recent results obtained using microneurography in our laboratory as well as those of others that have revealed new insights into mechanisms underlying compensatory increases in MSNA during progressive reductions in central blood volume and how MSNA is altered at the point of hemodynamic decompensation. We will also review recent work that has compared direct MSNA recordings with non-invasive surrogates of MSNA to determine the appropriateness of using such surrogates in assessing the clinical status of hemorrhaging patients.
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Affiliation(s)
- Kathy L Ryan
- U.S. Army Institute of Surgical Research Fort Sam Houston, TX, USA11
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20
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Mano T, Nishimura N, Iwase S. Sympathetic neural influence on bone metabolism in microgravity (Review). ACTA ACUST UNITED AC 2011; 97:354-61. [PMID: 21138811 DOI: 10.1556/aphysiol.97.2010.4.8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bone loss is one of the most important complications for astronauts who are exposed to long-term microgravity in space and also for bedridden elderly people. Recent studies have indicated that the sympathetic nervous system plays a role in bone metabolism. This paper reviews findings concerning with sympathetic influences on bone metabolism to hypothesize the mechanism how sympathetic neural functions are related to bone loss in microgravity. Animal studies have suggested that leptin stimulates hypothalamus increasing sympathetic outflow to bone and enhances bone resorption through noradrenaline and β-adrenoreceptors in bone. In humans, even though there have been some controversial findings, use of β-adrenoblockers has been reported to be beneficial for prevention of osteoporosis and bone fracture. On the other hand, microneurographically-recorded sympathetic nerve activity was enhanced by exposure to microgravity in space as well as dry immersion or long-term bed rest to simulate microgravity. The same sympathetic activity became higher in elderly people whose bone mass becomes generally reduced. Our recent findings indicated a significant correlation between muscle sympathetic nerve activity and urinary deoxypyridinoline as a specific marker measuring bone resorption. Based on these findings we would like to propose a following hypothesis concerning the sympathetic involvement in the mechanism of bone loss in microgravity: An exposure to prolonged microgravity may enhance sympathetic neural traffic not only to muscle but also to bone. This sympathetic enhancement increases plasma noradrenaline level and inhibits osteogenesis and facilitates bone resorption through β-adrenoreceptors in bone to facilitate bone resorption to reduce bone mass. The use of β-adrenoblockers to prevent bone loss in microgravity may be reasonable.
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Affiliation(s)
- Tadaaki Mano
- Gifu University of Medical Science Seki, Gifu 501-3892 Japan.
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Navasiolava NM, Pajot A, Gallois Y, Pastushkova LK, Kulchitsky VA, Gauquelin-Koch G, Kozlovskaya IB, Heer M, Hand O, Larina IM, Custaud MA. NT-ProBNP levels, water and sodium homeostasis in healthy men: effects of 7 days of dry immersion. Eur J Appl Physiol 2011; 111:2229-37. [PMID: 21327795 DOI: 10.1007/s00421-011-1858-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 01/29/2011] [Indexed: 11/28/2022]
Abstract
Immersion is a useful tool for studying fluid-volume homeostasis. Natriuretic peptides play a vital role in renal, humoral, and cardiovascular regulation under changing environmental conditions. We hypothesized that dry immersion would rapidly induce a new steady state for water and sodium metabolism, and that serum NT-proBNP levels, a proxy measure for brain natriuretic peptide (BNP), would decrease during long-term dry immersion and increase during recovery. Eight healthy young men were studied before, during, and after 7 days of dry immersion. Body weight, water balance, and plasma volume changes were evaluated. Plasma and serum samples were analyzed for active renin, NT-proBNP, aldosterone, electrolytes, osmolality, total protein, and creatinine. Urine samples were analyzed to determine levels of electrolytes, osmolality, creatinine, and free cortisol. A stand test was performed before and after dry immersion to evaluate cardiovascular deconditioning. Long-term dry immersion induced acute changes in water and sodium homeostasis on day 1, followed by a new steady state. Plasma volume decreased significantly during dry immersion. The serum levels of NT-proBNP increased significantly in recovery (10 ± 3 ng/L before dry immersion vs. 26 ± 5 ng/L on the fourth recovery day). Heart rate in the standing position was significantly greater after immersion. Results suggest that chronic dry immersion rapidly induced a new level of water-electrolyte homeostasis. The increase in NT-proBNP levels during the recovery period may be related to greater cardiac work and might reflect the degree of cardiovascular deconditioning.
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Navasiolava NM, Custaud MA, Tomilovskaya ES, Larina IM, Mano T, Gauquelin-Koch G, Gharib C, Kozlovskaya IB. Long-term dry immersion: review and prospects. Eur J Appl Physiol 2010; 111:1235-60. [PMID: 21161267 DOI: 10.1007/s00421-010-1750-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2010] [Indexed: 11/29/2022]
Abstract
Dry immersion, which is a ground-based model of prolonged conditions of microgravity, is widely used in Russia but is less well known elsewhere. Dry immersion involves immersing the subject in thermoneutral water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. For a relatively short duration, the model can faithfully reproduce most physiological effects of actual microgravity, including centralization of body fluids, support unloading, and hypokinesia. Unlike bed rest, dry immersion provides a unique opportunity to study the physiological effects of the lack of a supporting structure for the body (a phenomenon we call 'supportlessness'). In this review, we attempt to provide a detailed description of dry immersion. The main sections of the paper discuss the changes induced by long-term dry immersion in the neuromuscular and sensorimotor systems, fluid-electrolyte regulation, the cardiovascular system, metabolism, blood and immunity, respiration, and thermoregulation. The long-term effects of dry immersion are compared with those of bed rest and actual space flight. The actual and potential uses of dry immersion are discussed in the context of fundamental studies and applications for medical support during space flight and terrestrial health care.
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Navasiolava NM, Dignat-George F, Sabatier F, Larina IM, Demiot C, Fortrat JO, Gauquelin-Koch G, Kozlovskaya IB, Custaud MA. Enforced physical inactivity increases endothelial microparticle levels in healthy volunteers. Am J Physiol Heart Circ Physiol 2010; 299:H248-56. [DOI: 10.1152/ajpheart.00152.2010] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A sedentary lifestyle has adverse effects on the cardiovascular system, including impaired endothelial functions. Subjecting healthy men to 7 days of dry immersion (DI) presented a unique opportunity to analyze the specific effects of enhanced inactivity on the endothelium. We investigated endothelial properties before, during, and after 7 days of DI involving eight subjects. Microcirculatory functions were assessed with laser Doppler in the skin of the calf. We studied basal blood flow and endothelium-dependent and -independent vasodilation. We also measured plasma levels of microparticles, a sign of cellular dysfunction, and soluble endothelial factors, reflecting the endothelial state. Basal flow and endothelium-dependent vasodilation were reduced by DI (22 ± 4 vs. 15 ± 2 arbitrary units and 29 ± 6% vs. 12 ± 6%, respectively, P < 0.05), and this was accompanied by an increase in circulating endothelial microparticles (EMPs), which was significant on day 3 (42 ± 8 vs. 65 ± 10 EMPs/μl, P < 0.05), whereas microparticles from other cell origins remained unchanged. Plasma soluble VEGF decreased significantly during DI, whereas VEGF receptor 1 and soluble CD62E were unchanged, indicating that the increase in EMPs was associated with a change in antiapoptotic tone rather than endothelial activation. Our study showed that extreme physical inactivity in humans induced by 7 days of DI causes microvascular impairment with a disturbance of endothelial functions, associated with a selective increase in EMPs. Microcirculatory endothelial dysfunction might contribute to cardiovascular deconditioning as well as to hypodynamia-associated pathologies. In conclusion, the endothelium should be the focus of special care in situations of acute limitation of physical activity.
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Affiliation(s)
- Nastassia M. Navasiolava
- Centre National de la Recherche Scientifique UMR 6214, Institut National de la Santé et de la Recherche Médicale (INSERM) U771, Faculté de Médecine d'Angers, Angers
- Institute of Physiology of Minsk, Minsk, Belarus; and
- CaDyWEC International Laboratory, Faculté de Medicine d'Angers, Angers, France, and Institute of Biomedical Problems, Moscow, Russia
| | | | - Florence Sabatier
- INSERM U 608, Physiopathologie de l'Endothélium, Faculté de Pharmacie, Marseille, France
| | - Irina M. Larina
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
- CaDyWEC International Laboratory, Faculté de Medicine d'Angers, Angers, France, and Institute of Biomedical Problems, Moscow, Russia
| | - Claire Demiot
- EA3842, Homéostasie Cellulaire et Pathologies, Faculté de Pharmacie, Limoges
| | - Jacques-Olivier Fortrat
- Centre National de la Recherche Scientifique UMR 6214, Institut National de la Santé et de la Recherche Médicale (INSERM) U771, Faculté de Médecine d'Angers, Angers
- CaDyWEC International Laboratory, Faculté de Medicine d'Angers, Angers, France, and Institute of Biomedical Problems, Moscow, Russia
| | | | | | - Marc-Antoine Custaud
- Centre National de la Recherche Scientifique UMR 6214, Institut National de la Santé et de la Recherche Médicale (INSERM) U771, Faculté de Médecine d'Angers, Angers
- CaDyWEC International Laboratory, Faculté de Medicine d'Angers, Angers, France, and Institute of Biomedical Problems, Moscow, Russia
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Avolio AP, Butlin M, Walsh A. Arterial blood pressure measurement and pulse wave analysis-–their role in enhancing cardiovascular assessment. Physiol Meas 2009; 31:R1-47. [DOI: 10.1088/0967-3334/31/1/r01] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Grenon SM, Hurwitz S, Sheynberg N, Xiao X, Ramsdell CD, Mai CL, Kim C, Cohen RJ, Williams GH. Role of individual predisposition in orthostatic intolerance before and after simulated microgravity. J Appl Physiol (1985) 2004; 96:1714-22. [PMID: 15075309 DOI: 10.1152/japplphysiol.01274.2003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Orthostatic intolerance (OI) is a major problem after spaceflight. Its etiology remains uncertain, but reports have pointed toward an individual susceptibility to OI. We hypothesized that individual predisposition plays an important role in post-bed rest OI. Twenty-four healthy male subjects were equilibrated on a constant diet, after which they underwent tilt-stand test (pre-TST). They then completed 14-16 days of head-down-tilt bed rest, and 14 of the subjects underwent repeat tilt-stand test (post-TST). During various phases, the following were performed: 24-h urine collections and hormonal measurements, plethysmography, and cardiovascular system identification (a noninvasive method to assess autonomic function and separately quantify parasympathetic and sympathetic responsiveness). Development of presyncope or syncope defined OI. During pre-TST, 11 subjects were intolerant and 13 were tolerant. At baseline, intolerant subjects had lower serum aldosterone (P < 0.01), higher excretion of potassium (P = 0.01), lower leg venous compliance (P = 0.03), higher supine parasympathetic responsiveness (P = 0.02), and lower standing sympathetic responsiveness (P = 0.048). Of the 14 subjects who completed post-TST, 9 were intolerant and 5 were tolerant. Intolerant subjects had lower baseline serum cortisol (P = 0.03) and a higher sodium level (P = 0.02) compared with tolerant subjects. Thus several physiological characteristics were associated with increased susceptibility to OI. We propose a new model for OI, whereby individuals with greater leg venous compliance recruit compensatory mechanisms (activation of the renin-angiotensin-aldosterone system and sympathetic nervous system, and withdrawal of the parasympathetic nervous system) in the face of daily postural challenges, which places them at an advantage to face orthostatic stress. With head-down-tilt bed rest, the stimulus to recruit compensatory mechanisms disappears, and differences between the two subgroups attenuate.
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Affiliation(s)
- S M Grenon
- Division of Endocrinology, Hypertension and Diabetes, Brigham and Women's Hospital, Boston, MA 02115, USA
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Blaber AP, Bondar RL, Kassam MS. Heart rate variability and short duration spaceflight: relationship to post-flight orthostatic intolerance. BMC PHYSIOLOGY 2004; 4:6. [PMID: 15113425 PMCID: PMC420472 DOI: 10.1186/1472-6793-4-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2003] [Accepted: 04/27/2004] [Indexed: 11/15/2022]
Abstract
Background Upon return from space many astronauts experience symptoms of orthostatic intolerance. Research has implicated altered autonomic cardiovascular regulation due to spaceflight with further evidence to suggest that there might be pre-flight autonomic indicators of post-flight orthostatic intolerance. We used heart rate variability (HRV) to determine whether autonomic regulation of the heart in astronauts who did or did not experience post-flight orthostatic intolerance was different pre-flight and/or was differentially affected by short duration (8 – 16 days) spaceflight. HRV data from ten-minute stand tests collected from the 29 astronauts 10 days pre-flight, on landing day and three days post-flight were analysed using coarse graining spectral analysis. From the total power (PTOT), the harmonic component was extracted and divided into high (PHI: >0.15 Hz) and low (PLO: = 0.15 Hz) frequency power regions. Given the distribution of autonomic nervous system activity with frequency at the sinus node, PHI/PTOT was used as an indicator of parasympathetic activity; PLO/PTOT as an indicator of sympathetic activity; and, PLO/PHI as an estimate of sympathovagal balance. Results Twenty-one astronauts were classified as finishers, and eight as non-finishers, based on their ability to remain standing for 10 minutes on landing day. Pre-flight, non-finishers had a higher supine PHI/PTOT than finishers. Supine PHI/PTOT was the same pre-flight and on landing day in the finishers; whereas, in the non-finishers it was reduced. The ratio PLO/PHI was lower in non-finishers compared to finishers and was unaffected by spaceflight. Pre-flight, both finishers and non-finishers had similar supine values of PLO/PTOT, which increased from supine to stand. Following spaceflight, only the finishers had an increase in PLO/PTOT from supine to stand. Conclusions Both finishers and non-finishers had an increase in sympathetic activity with stand on pre-flight, yet only finishers retained this response on landing day. Non-finishers also had lower sympathovagal balance and higher pre-flight supine parasympathetic activity than finishers. These results suggest pre-flight autonomic status and post-flight impairment in autonomic control of the heart may contribute to orthostatic intolerance. The mechanism by which higher pre-flight parasympathetic activity might contribute to post-flight orthostatic intolerance is not understood and requires further investigation.
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Affiliation(s)
- Andrew P Blaber
- School of Kinesiology, Simon Fraser University, Burnaby, BC, Canada N6A 3K7
| | - Roberta L Bondar
- Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3
| | - Mahmood S Kassam
- Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3
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Mano T, Iwase S. Sympathetic nerve activity in hypotension and orthostatic intolerance. ACTA PHYSIOLOGICA SCANDINAVICA 2003; 177:359-65. [PMID: 12609007 DOI: 10.1046/j.1365-201x.2003.01081.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM The present paper reviews how changes in sympathetic nerve activity are related to hypotensive episodes and orthostatic intolerance in humans. RESULTS It has been well documented that sympathetic neural traffic to skeletal muscles (muscle sympathetic nerve activity; MSNA) plays an essential role in maintaining blood pressure homeostasis mainly through baroreflex. The MSNA responded to gravitational loading from the head to the leg (+Gz) during passive head-up tilt (HUT). Patients who suffered from orthostatic hypotension with or without syncope were classified into at least two groups; low and high responders of MSNA to orthostatic loading. The typical examples belonging to the former group were patients of multiple system atrophy who had very low basal sympathetic outflow to muscle which responded extremely poorly to HUT. Patients of multiple system atrophy presented also postprandial hypotension in which muscle sympathetic response to oral glucose administration was absent. The latter group was represented by subjects who manifested vasovagal syncope with normal or even higher muscle sympathetic response to HUT, which was suddenly withdrawn concomitantly with bradycardia and hypotension. Similar withdrawal of sympathetic nerve traffic to muscle was encountered in a rare case of idiopathic non-orthostatic episodic hypotension which accompanied bradycardia. The MSNA was suppressed by short-term exposure to microgravity but was enhanced after long-term exposure to microgravity. Orthostatic intolerance after long-term exposure to microgravity was related to progressive reduction of muscle sympathetic response to orthostatic loading with impaired arterial baroreflex. CONCLUSION It is concluded that hypotensive episodes are closely related to poor or lack of muscle sympathetic outflow, but may depend on various neural mechanisms to induce it.
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Affiliation(s)
- T Mano
- Tokai Central Hospital, Kakamigahara, Gifu, Japan
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Abstract
Muscle sympathetic nerve activity (MSNA) can be directly recorded from human peripheral nerves in situ using microneurography. MSNA plays an essential role to control systemic blood pressure against gravitational stress. MSNA was enhanced by changing posture against terrestrial gravity from lying to sitting, and from sitting to standing. This activity was enhanced by head-up tilt depending on the gravitational input from the head to the leg (+Gz) in the human body. Orthostatic hypotension occurred when MSNA response to gravitational stress was impaired both in high and low responders of this sympathetic outflow. Syncope was preceded and/or associated by a withdrawal of MSNA. MSNA was suppressed by short-term exposure to microgravity but was enhanced after long-term exposure to microgravity. Orthostatic intolerance after exposure to prolonged microgravity was associated with a reduction of increased MSNA response to gravitational stress. Aging influenced gravity-related responses of MSNA.
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Affiliation(s)
- T Mano
- Tokai Central Hospital, Kakamigahara, Gifu, Japan.
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Morita H, Tanaka K, Tsuchiya Y, Miyahara T, Fujiki N. Response of renal sympathetic nerve activity to parabolic flight-induced gravitational change in conscious rats. Neurosci Lett 2001; 310:129-32. [PMID: 11585584 DOI: 10.1016/s0304-3940(01)02099-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The renal sympathetic nerve activity (RNA) response to gravitational changes induced by parabolic flight was examined in chronically instrumented conscious rats. Two types of RNA responses were found. In six out of 12 rats, the RNA did not respond during the 2 G period, but immediately fell to background levels on entry into microgravity (microG), then recovered to the 1 G control level during continued microG (shutdown obvious group). In the other six rats, the RNA increased to 158+/-13% at the end of the 2 G period, increased further to 195+/-22% on entry into microG, then gradually recovered to that seen at 1 G (shutdown obscure group). The mean arterial pressure in the shutdown obvious group was significantly higher and the heart rate tended to be higher than in the shutdown obscure group, suggesting that the baseline sympathetic tone in the shutdown obvious group was higher than in the shutdown obscure group. These results suggest that the RNA response to parabolic flight might be affected by the baseline sympathetic tone.
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Affiliation(s)
- H Morita
- Department of Physiology, Gifu University School of Medicine, 40 Tsukasa-Machi, Gifu 500-8705, Japan.
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Kamiya A, Iwase S, Michikami D, Fu Q, Mano T. Head-down bed rest alters sympathetic and cardiovascular responses to mental stress. Am J Physiol Regul Integr Comp Physiol 2000; 279:R440-7. [PMID: 10938230 DOI: 10.1152/ajpregu.2000.279.2.r440] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Astronauts usually work under much mental stress. However, it is unclear how and whether or not an exposure to microgravity affects physiological response to mental stress in humans. To examine effects of microgravity on vasomotor sympathetic and peripheral vasodilator responses to mental stress, we performed 10 min of mental arithmetic (MA) before and after 14 days of 6 degrees head-down bed rest (HDBR), a ground-based simulation of spaceflight. Total muscle sympathetic nerve activity (MSNA, measured by microneurography) slightly increased during MA before HDBR, and this increase was augmented after HDBR. Calf blood flow (measured by venous occlusion plethysmography) increased and calf vascular resistance (calculated by dividing mean blood pressure by calf blood flow) decreased during MA before HDBR, but these responses were abolished after HDBR. Increases in heart rate and mean blood pressure during MA were not different between before and after HDBR. These findings suggest that HDBR augmented vasomotor sympathoexcitation but attenuated vasodilatation in the calf muscle in response to mental stress.
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Affiliation(s)
- A Kamiya
- Department of Autonomic Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
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Kamiya A, Iwase S, Michikami D, Fu Q, Mano T, Kitaichi K, Takagi K. Increased vasomotor sympathetic nerve activity and decreased plasma nitric oxide release after head-down bed rest in humans: disappearance of correlation between vasoconstrictor and vasodilator. Neurosci Lett 2000; 281:21-4. [PMID: 10686406 DOI: 10.1016/s0304-3940(00)00804-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We hypothesized that the relationship between resting levels of sympathetic vasoconstrictor nerve traffic and dilator substance nitric oxide (NO) release is altered after exposure to microgravity, resulting in abnormal peripheral resistance. To examine the hypothesis, we assessed muscle sympathetic nerve activity (MSNA) (microneurography), an indicator of NO release (plasma nitrite/nitrate concentrations) and leg vascular resistance (venous occlusion plethysmography) in 20 healthy male volunteers before and after 14 days of 6 degrees head-down bed rest (HDBR), the ground-based analogue of microgravity. MSNA increased, while plasma nitrite/nitrate concentrations decreased after HDBR. A significant positive correlation observed between MSNA and plasma nitrite/nitrate concentrations before HDBR disappeared after HDBR. Leg vascular resistance increased after HDBR. In conclusion, an imbalance between sympathetic vasoconstrictor traffic and NO release might contribute to elevated peripheral vascular resistance following HDBR.
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Affiliation(s)
- A Kamiya
- Department of Autonomic Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
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