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Merchant HN, Thirkell JE, Portugal SJ. No evidence for a signal in mammalian basal metabolic rate associated with a fossorial lifestyle. Sci Rep 2024; 14:11297. [PMID: 38760353 PMCID: PMC11101413 DOI: 10.1038/s41598-024-61595-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 05/07/2024] [Indexed: 05/19/2024] Open
Abstract
A vast array of challenging environments are inhabited by mammals, such as living in confined spaces where oxygen levels are likely to be low. Species can exhibit adaptations in basal metabolic rate (BMR) to exploit such unique niches. In this study we use 801 species to determine the relationship between BMR and burrow use in mammals. We included pre-existing data for mammalian BMR and 16 life history traits. Overall, mammalian BMR is dictated primarily by environmental ambient temperature. There were no significant differences in BMR of terrestrial, semi-fossorial and fossorial mammals, suggesting that species occupying a subterranean niche do not exhibit baseline metabolic costs on account of their burrowing lifestyle. Fossorial mammals likely show instantaneous metabolic responses to low oxygen in tunnels, rather than exhibit adaptive long-term responses in their BMR.
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Affiliation(s)
- Hana N Merchant
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Jack E Thirkell
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Steven J Portugal
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
- Department of Biology, University of Oxford, OX1 3SZ, Oxford, United Kingdom
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2
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Haouzi P, Lewis T. Hypothalamus pre-optic area and metabolism regulation in humans. Nat Metab 2023; 5:1442. [PMID: 37524786 DOI: 10.1038/s42255-023-00858-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Affiliation(s)
- Philippe Haouzi
- Department of Pulmonary Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, OH, USA.
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
| | - Tristan Lewis
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
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3
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Abstract
AbstractThe idea of putting astronauts into a hibernation-like state during interplanetary spaceflights has sparked new interest in the evolutionary roots of hibernation and torpor. In this context, it should be noted that mammalian fetuses and neonates respond to the environmental challenges in the perinatal period with a number of physiological mechanisms that bear striking similarity to hibernation and torpor. These include three main points: first, prenatal deviation from the overall metabolic size relationship, which adapts the fetus to the low-oxygen conditions in the womb and corresponds to the metabolic reduction during hibernation and estivation; second, intranatal diving bradycardia in response to shortened O2 supply during birth, comparable to the decrease in heart rate preceding the drop in body temperature upon entry into torpor; and third, postnatal onset of nonshivering thermogenesis in the brown adipose tissue, along with the increase in basal metabolic rate up to the level expected from body size, such as during arousal from hibernation. The appearance of hibernation-like adaptations in the perinatal period suggests that, conversely, hibernation and torpor may be composed of mechanisms shared by all mammals around birth. This hypothesis sheds new light on the origins of hibernation and supports its potential accessibility to nonhibernating species, including humans.
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4
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Yap KN, Wong HS, Ramanathan C, Rodriguez-Wagner CA, Roberts MD, Freeman DA, Buffenstein R, Zhang Y. Naked mole-rat and Damaraland mole-rat exhibit lower respiration in mitochondria, cellular and organismal levels. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148582. [PMID: 35667393 DOI: 10.1016/j.bbabio.2022.148582] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Naked mole-rats (NMR) and Damaraland mole-rats (DMR) exhibit extraordinary longevity for their body size, high tolerance to hypoxia and oxidative stress and high reproductive output; these collectively defy the concept that life-history traits should be negatively correlated. However, when life-history traits share similar underlying physiological mechanisms, these may be positively associated with each other. We propose that one such potential common mechanism might be the bioenergetic properties of mole-rats. Here, we aim to characterize the bioenergetic properties of two African mole-rats. We adopted a top-down perspective measuring the bioenergetic properties at the organismal, cellular, and molecular level in both species and the biological significance of these properties were compared with the same measures in Siberian hamsters and C57BL/6 mice, chosen for their similar body size to the mole-rat species. We found mole-rats shared several bioenergetic properties that differed from their comparison species, including low basal metabolic rates, a high dependence on glycolysis rather than on oxidative phosphorylation for ATP production, and low proton conductance across the mitochondrial inner membrane. These shared mole-rat features could be a result of evolutionary adaptation to tolerating variable oxygen atmospheres, in particular hypoxia, and may in turn be one of the molecular mechanisms underlying their extremely long lifespans.
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Affiliation(s)
- Kang Nian Yap
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America; Department of Biology, Norwegian University of Science and Technology, Trondheim 7491, Norway
| | - Hoi Shan Wong
- Calico Life Sciences LLC, South San Francisco, CA 94080, United States of America
| | - Chidambaram Ramanathan
- College of Health Sciences, University of Memphis, Memphis, TN 38152, United States of America
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL 36849, United States of America
| | - David A Freeman
- Department of Biological Science, University of Memphis, Memphis, TN 38152, United States of America
| | - Rochelle Buffenstein
- Calico Life Sciences LLC, South San Francisco, CA 94080, United States of America.
| | - Yufeng Zhang
- College of Health Sciences, University of Memphis, Memphis, TN 38152, United States of America.
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5
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Lara-Cantón I, Badurdeen S, Dekker J, Davis P, Roberts C, Te Pas A, Vento M. Oxygen saturation and heart rate in healthy term and late preterm infants with delayed cord clamping. Pediatr Res 2022:10.1038/s41390-021-01805-y. [PMID: 34997223 DOI: 10.1038/s41390-021-01805-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/03/2021] [Accepted: 10/06/2021] [Indexed: 01/10/2023]
Abstract
Blood oxygen in the fetus is substantially lower than in the newborn infant. In the minutes after birth, arterial oxygen saturation rises from around 50-60% to 90-95%. Initial respiratory efforts generate negative trans-thoracic pressures that drive liquid from the airways into the lung interstitium facilitating lung aeration, blood oxygenation, and pulmonary artery vasodilatation. Consequently, intra- (foramen ovale) and extra-cardiac (ductus arteriosus) shunting changes and the sequential circulation switches to a parallel pulmonary and systemic circulation. Delaying cord clamping preserves blood flow through the ascending vena cava, thus increasing right and left ventricular preload. Recently published reference ranges have suggested that delayed cord clamping positively influenced the fetal-to-neonatal transition. Oxygen saturation in babies with delayed cord clamping plateaus significantly earlier to values of 85-90% than in babies with immediate cord clamping. Delayed cord clamping may also contribute to fewer episodes of brady-or-tachycardia in the first minutes after birth, but data from randomized trials are awaited. IMPACT: Delaying cord clamping during fetal to neonatal transition contributes to a significantly earlier plateauing of oxygen saturation and fewer episodes of brady-and/or-tachycardia in the first minutes after birth. We provide updated information regarding the changes in SpO2 and HR during postnatal adaptation of term and late preterm infants receiving delayed compared with immediate cord clamping. Nomograms in newborn infants with delayed cord clamping will provide valuable reference ranges to establish target SpO2 and HR in the first minutes after birth.
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Affiliation(s)
- Inmaculada Lara-Cantón
- Neonatal Research Group, Health Research Institute and University and Polytechnic Hospital La Fe, Valencia, Spain
| | - Shiraz Badurdeen
- Newborn Research Center and Neonatal Services, The Royal Women´s Hospital, Melbourne, VIC, Australia
| | - Janneke Dekker
- Division of Neonatology, Department of Paediatrics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Peter Davis
- Newborn Research Center and Neonatal Services, The Royal Women´s Hospital, Melbourne, VIC, Australia
| | - Calum Roberts
- Department of Paediatrics, Monash University, Clayton, VIC, Australia
| | - Arjan Te Pas
- Division of Neonatology, Department of Paediatrics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Máximo Vento
- Neonatal Research Group, Health Research Institute and University and Polytechnic Hospital La Fe, Valencia, Spain.
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6
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Singer D. Pediatric Hypothermia: An Ambiguous Issue. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:11484. [PMID: 34769999 PMCID: PMC8583576 DOI: 10.3390/ijerph182111484] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/17/2021] [Accepted: 10/19/2021] [Indexed: 02/06/2023]
Abstract
Hypothermia in pediatrics is mainly about small body size. The key thermal factor here is the large surface-to-volume ratio. Although small mammals, including human infants and children, are adapted to higher heat losses through their elevated metabolic rate and thermogenic capacity, they are still at risk of hypothermia because of a small regulatory range and an impending metabolic exhaustion. However, some small mammalian species (hibernators) use reduced metabolic rates and lowered body temperatures as adaptations to impaired energy supply. Similar to nature, hypothermia has contradictory effects in clinical pediatrics as well: In neonates, it is a serious risk factor affecting respiratory adaptation in term and developmental outcome in preterm infants. On the other hand, it is an important self-protective response to neonatal hypoxia and an evidence-based treatment option for asphyxiated babies. In children, hypothermia first enabled the surgical repair of congenital heart defects and promotes favorable outcome after ice water drowning. Yet, it is also a major threat in various prehospital and clinical settings and has no proven therapeutic benefit in pediatric critical care. All in all, pediatric hypothermia is an ambiguous issue whose harmful or beneficial effects strongly depend on the particular circumstances.
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Affiliation(s)
- Dominique Singer
- Division of Neonatology and Pediatric Critical Care Medicine, University Medical Center Eppendorf, 20246 Hamburg, Germany
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Krieger NS, Bushinsky DA. Metabolic Acidosis Regulates RGS16 and G-protein Signaling in Osteoblasts. Am J Physiol Renal Physiol 2021; 321:F424-F430. [PMID: 34396788 DOI: 10.1152/ajprenal.00166.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic metabolic acidosis stimulates cell-mediated net calcium efflux from bone mediated by increased osteoblastic cyclooxygenase 2 (COX2), leading to prostaglandin E2-induced stimulation of RANKL-induced osteoclastic bone resorption. The osteoblastic H+-sensing G-protein coupled receptor (GPCR), OGR1, is activated by acidosis and leads to increased bne resorption. As regulators of G protein signaling (RGS) proteins limit GPCR signaling, we tested whether RGS proteins themselves are regulated by metabolic acidosis. Primary osteoblasts were isolated from neonatal mouse calvariae and incubated in physiological neutral (NTL) or acidic (MET) medium. Cells were collected and RNA extracted for real time PCR analysis with mRNA levels normalized to RPL13a. RGS1, RGS2, RGS3, RGS4, RGS10, RGS11 or RGS18mRNA did not differ between MET and NTL; however by 30' MET decreased RGS16 which persisted for 60' and 3h. Incubation of osteoblasts with the OGR1 inhibitor CuCl2 inhibited the MET induced increase in RGS16 mRNA. Gallein, a specific inhibitor of Gβγ signaling, was used to determine if downstream signaling by the βγ subunit was critical for the response to acidosis. Gallein decreased net Ca efflux from calvariae and COX2 and RANKL gene expression from isolated osteoblasts. These results indicate that regulation of RGS16 plays an important role in modulating the response of the osteoblastic GPCR, OGR1, to metabolic acidosis and subsequent stimulation of osteoclastic bone resorption.
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Affiliation(s)
- Nancy S Krieger
- Division of Nephrology, Department of Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - David A Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester Medical Center, Rochester, NY, United States
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8
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Singer D. [Surviving the Lack: Natural Adaptations in Newborns]. Z Geburtshilfe Neonatol 2020; 225:203-215. [PMID: 33285584 DOI: 10.1055/a-1019-6007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Newborns are equipped with a number of natural adaptation mechanisms preventing them from impaired energy supply, despite their elevated (size-related) metabolic rate. These include the diving response known from aquatic mammals, which - being composed of apnea, bradycardia, and vasoconstriction - ensures an economical use of O2 reserves and results in a subsequent influx of lactate out of peripheral tissues. From a metabolic point of view, mammalian fetuses behave "like an organ of the mother" and thus exhibit a hibernation-like deviation from the overall metabolic size relationship that adapts them to the limited intrauterine O2/substrate availability. In case of lacking supply, they can reduce their energy demands even further by foregoing growth, with the placenta acting as a gatekeeper. Postnatal hypoxia does not only result in the suppression of non-shivering thermogenesis, but also in a hypoxic hypometabolism that otherwise has only been known from poikilothermic animals. After prolonged apnea, gasps do occur that maintain a rudimentary heart action through short elevations in pO2 (autoresuscitation). Overall, these mechanisms postpone a critical O2 deficit and thereby provide a "resistance" rather than a "tolerance" to hypoxia. As they are based on an (active) reduction in energy demand, they are not easy to distinguish from the (passive) breakdown of metabolism resulting from hypoxia.
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9
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Krieger NS, Chen L, Becker J, Chan MR, Bushinsky DA. Deletion of the proton receptor OGR1 in mouse osteoclasts impairs metabolic acidosis-induced bone resorption. Kidney Int 2020; 99:609-619. [PMID: 33159961 DOI: 10.1016/j.kint.2020.10.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 09/30/2020] [Accepted: 10/09/2020] [Indexed: 01/03/2023]
Abstract
Metabolic acidosis induces osteoclastic bone resorption and inhibits osteoblastic bone formation. Previously we found that mice with a global deletion of the proton receptor OGR1 had increased bone density although both osteoblast and osteoclast activity were increased. To test whether direct effects on osteoclast OGR1 are critical for metabolic acidosis stimulated bone resorption, we generated knockout mice with an osteoclast-specific deletion of OGR1 (knockout mice). We studied bones from three-month old female mice and the differentiated osteoclasts derived from bone marrow of femurs from these knockout and wild type mice. MicroCT demonstrated increased density in tibiae and femurs but not in vertebrae of the knockout mice. Tartrate resistant acid phosphatase staining of tibia indicated a decrease in osteoclast number and surface area/bone surface from knockout compared to wild type mice. Osteoclasts derived from the marrow of knockout mice demonstrated decreased pit formation, osteoclast staining and osteoclast-specific gene expression compared to those from wild type mice. In response to metabolic acidosis, osteoclasts from knockout mice had decreased nuclear translocation of NFATc1, a transcriptional regulator of differentiation, and no increase in size or number compared to osteoclasts from wild type mice. Thus, loss of osteoclast OGR1 decreased both basal and metabolic acidosis-induced osteoclast activity indicating osteoclast OGR1 is important in mediating metabolic acidosis-induced bone resorption. Understanding the role of OGR1 in metabolic acidosis-induced bone resorption will provide insight into bone loss in acidotic patients with chronic kidney disease.
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Affiliation(s)
- Nancy S Krieger
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine, Rochester, New York, USA.
| | - Luojing Chen
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine, Rochester, New York, USA
| | - Jennifer Becker
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine, Rochester, New York, USA
| | - Michaela R Chan
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine, Rochester, New York, USA
| | - David A Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine, Rochester, New York, USA
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10
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Cetin I, Taricco E, Mandò C, Radaelli T, Boito S, Nuzzo AM, Giussani DA. Fetal Oxygen and Glucose Consumption in Human Pregnancy Complicated by Fetal Growth Restriction. Hypertension 2020; 75:748-754. [PMID: 31884857 DOI: 10.1161/hypertensionaha.119.13727] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In healthy pregnancy, glucose and oxygen availability are essential for fetal growth and well being. However, how substrate delivery and fetal uptake are affected in human pregnancy complicated by fetal growth restriction (FGR) is still unknown. Here, we show that the human FGR fetus has a strikingly reduced umbilical uptake of both oxygen and glucose. In 30 healthy term and 32 FGR human pregnancies, umbilical volume flow (Qumb) and parallel umbilical vein (uv) and artery (ua) blood samples were obtained at elective Cesarean section to calculate fetal glucose and oxygen uptake as Qumb · Δ (uv-ua) differences. Umbilical blood flow was significantly lower in FGR pregnancy (-63%; P<0.001) but not when normalized for fetal body weight. FGR pregnancy had significantly lower umbilical oxygen delivery and uptake, both as absolute values (delivery: -78%; uptake: -78%) and normalized (delivery: -50%; uptake: -48%) for fetal body weight (all P<0.001). Umbilical glucose absolute delivery and uptake were significantly reduced (delivery: -68%; uptake: -72%) but only glucose uptake was decreased when normalized for fetal body weight (-30%; P<0.05). The glucose/oxygen quotient was significantly increased (+100%; P<0.05) while glucose clearance was significantly decreased (71%; P<0.001) in FGR pregnancy (both P<0.05). The human fetus in FGR pregnancy triggers compensatory mechanisms to reduce its metabolic rate, matching the proportion of substrate consumption relative to oxygen delivery as a survival strategy during complicated pregnancy.
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Affiliation(s)
- Irene Cetin
- From the Department of Biomedical and Clinical Sciences Luigi Sacco, Università degli Studi di Milano, Italy (I.C., E.T., C.M.)
| | - Emanuela Taricco
- From the Department of Biomedical and Clinical Sciences Luigi Sacco, Università degli Studi di Milano, Italy (I.C., E.T., C.M.)
| | - Chiara Mandò
- From the Department of Biomedical and Clinical Sciences Luigi Sacco, Università degli Studi di Milano, Italy (I.C., E.T., C.M.)
| | - Tatjana Radaelli
- Department of Obstetrics and Gynecology "L. Mangiagalli", Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy (T.R., S.B.)
| | - Simona Boito
- Department of Obstetrics and Gynecology "L. Mangiagalli", Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy (T.R., S.B.)
| | - Anna Maria Nuzzo
- Department of Surgical Sciences, University of Turin, Italy (A.M.N.)
| | - Dino A Giussani
- Department of Physiology Development and Neuroscience, University of Cambridge, United Kingdom (D.A.G.)
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11
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Ferner K, Schultz JA, Zeller U. Comparative anatomy of neonates of the three major mammalian groups (monotremes, marsupials, placentals) and implications for the ancestral mammalian neonate morphotype. J Anat 2017; 231:798-822. [PMID: 28960296 PMCID: PMC5696127 DOI: 10.1111/joa.12689] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2017] [Indexed: 12/16/2022] Open
Abstract
The existing different modes of reproduction in monotremes, marsupials and placentals are the main source for our current understanding of the origin and evolution of the mammalian reproduction. The reproductive strategies and, in particular, the maturity states of the neonates differ remarkably between the three groups. Monotremes, for example, are the only extant mammals that lay eggs and incubate them for the last third of their embryonic development. In contrast, marsupials and placentals are viviparous and rely on intra-uterine development of the neonates via choriovitelline (mainly marsupials) and chorioallantoic (mainly placentals) placentae. The maturity of a newborn is closely linked to the parental care strategy once the neonate is born. The varying developmental degrees of neonates are the main focus of this study. Monotremes and marsupials produce highly altricial and nearly embryonic offspring. Placental mammals always give birth to more developed newborns with the widest range from altricial to precocial. The ability of a newborn to survive and grow in the environment it was born in depends highly on the degree of maturation of vital organs at the time of birth. Here, the anatomy of four neonates of the three major extant mammalian groups is compared. The basis for this study is histological and ultrastructural serial sections of a hatchling of Ornithorhynchus anatinus (Monotremata), and neonates of Monodelphis domestica (Marsupialia), Mesocricetus auratus (altricial Placentalia) and Macroscelides proboscideus (precocial Placentalia). Special attention was given to the developmental stages of the organs skin, lung, liver and kidney, which are considered crucial for the maintenance of vital functions. The state of the organs of newborn monotremes and marsupials are found to be able to support a minimum of vital functions outside the uterus. They are sufficient to survive, but without capacities for additional energetic challenges. The organs of the altricial placental neonate are further developed, able to support the maintenance of vital functions and short-term metabolic increase. The precocial placental newborn shows the most advanced state of organ development, to allow the maintenance of vital functions, stable thermoregulation and high energetic performance. The ancestral condition of a mammalian neonate is interpreted to be similar to the state of organ development found in the newborns of marsupials and monotremes. In comparison, the newborns of altricial and precocial placentals are derived from the ancestral state to a more mature developmental degree associated with advanced organ systems.
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Affiliation(s)
- Kirsten Ferner
- Leibniz‐Institut für Evolutions‐ und BiodiversitätsforschungMuseum für NaturkundeBerlinGermany
| | - Julia A. Schultz
- Department of Organismal Biology and AnatomyUniversity of ChicagoChicagoILUSA
| | - Ulrich Zeller
- Lebenswissenschaftliche FakultätFG Spezielle ZoologieAlbrecht Daniel Thaer‐Institut für Agrar‐ und GartenbauwissenschaftenHumboldt‐Universität zu BerlinBerlinGermany
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12
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Li S, Hafeez A, Noorulla F, Geng X, Shao G, Ren C, Lu G, Zhao H, Ding Y, Ji X. Preconditioning in neuroprotection: From hypoxia to ischemia. Prog Neurobiol 2017; 157:79-91. [PMID: 28110083 DOI: 10.1016/j.pneurobio.2017.01.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 01/08/2017] [Accepted: 01/13/2017] [Indexed: 01/05/2023]
Abstract
Sublethal hypoxic or ischemic events can improve the tolerance of tissues, organs, and even organisms from subsequent lethal injury caused by hypoxia or ischemia. This phenomenon has been termed hypoxic or ischemic preconditioning (HPC or IPC) and is well established in the heart and the brain. This review aims to discuss HPC and IPC with respect to their historical development and advancements in our understanding of the neurochemical basis for their neuroprotective role. Through decades of collaborative research and studies of HPC and IPC in other organ systems, our understanding of HPC and IPC-induced neuroprotection has expanded to include: early- (phosphorylation targets, transporter regulation, interfering RNA) and late- (regulation of genes like EPO, VEGF, and iNOS) phase changes, regulators of programmed cell death, members of metabolic pathways, receptor modulators, and many other novel targets. The rapid acceleration in our understanding of HPC and IPC will help facilitate transition into the clinical setting.
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Affiliation(s)
- Sijie Li
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuan Wu Hospital, Capital Medical University, Beijing, China; National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Adam Hafeez
- Department of Neurological Surgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Fatima Noorulla
- Department of Neurological Surgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Xiaokun Geng
- Department of Neurological Surgery, Wayne State University School of Medicine, Detroit, MI, USA; Department of Neurology, Luhe Hospital, Capital Medical University, Beijing, China
| | - Guo Shao
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Changhong Ren
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Guowei Lu
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Heng Zhao
- Department of Neurosurgery, Stanford University, CA, USA
| | - Yuchuan Ding
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuan Wu Hospital, Capital Medical University, Beijing, China; Department of Neurological Surgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Xunming Ji
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuan Wu Hospital, Capital Medical University, Beijing, China; National Clinical Research Center for Geriatric Disorders, Beijing, China.
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13
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Krieger NS, Yao Z, Kyker-Snowman K, Kim MH, Boyce BF, Bushinsky DA. Increased bone density in mice lacking the proton receptor OGR1. Kidney Int 2016; 89:565-73. [PMID: 26880453 DOI: 10.1016/j.kint.2015.12.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 08/18/2015] [Accepted: 09/09/2015] [Indexed: 12/24/2022]
Abstract
Chronic metabolic acidosis stimulates cell-mediated calcium efflux from bone through osteoblastic prostaglandin E2-induced stimulation of receptor activator of NF-kB ligand leading to increased osteoclastic bone resorption. Osteoblasts express the proton-sensing G-protein-coupled receptor OGR1, which activates inositol phosphate-mediated intracellular calcium. Proton-induced osteoblastic intracellular calcium signaling requires ovarian cancer G-protein-coupled receptor 1 (OGR1), suggesting that OGR1 is the sensor activated during acidosis to cause bone resorption. Growing mice produce large amounts of metabolic acids, which must be buffered, primarily by bone, before excretion by the kidney. Here we tested whether lack of OGR1 inhibits proton-induced bone resorption by measuring bone mineral density by micro-computed tomography and histomorphometry in 8-week-old male OGR1(-/-) and C57/Bl6 wild type mice. OGR1(-/-) mice have normal skeletal development with no atypical gross phenotype. Trabecular and cortical bone volume was increased in tibiae and vertebrae from OGR1(-/-). There were increased osteoblast numbers on the cortical and trabecular surfaces of tibiae from OGR1(-/-) mice, increased endocortical and trabecular bone formation rates, and osteoblastic gene expression. Osteoclast numbers and surface were increased in tibiae of OGR1(-/-) mice. Thus, in rapidly growing mice, lack of OGR1 leads to increased bone mass with increased bone turnover and a greater increase in bone formation than resorption. This supports the important role of the proton receptor OGR1 in the response of bone to protons.
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Affiliation(s)
- Nancy S Krieger
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
| | - Zhenqiang Yao
- Department of Pathology, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Kelly Kyker-Snowman
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Min Ho Kim
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Brendan F Boyce
- Department of Pathology, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - David A Bushinsky
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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14
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Burger M, van Breukelen F. Construction of a low cost and highly sensitive direct heat calorimeter suitable for estimating metabolic rate in small animals. J Therm Biol 2013. [DOI: 10.1016/j.jtherbio.2013.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Haouzi P, Van de Louw A. Uncoupling mitochondrial activity maintains body [Formula: see text] during hemorrhage-induced O2 deficit in the anesthetized rat. Respir Physiol Neurobiol 2013; 186:87-94. [PMID: 23333818 DOI: 10.1016/j.resp.2012.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 01/25/2023]
Abstract
During a hemorrhagic shock (HS), O2 uptake ( [Formula: see text] ) decreases as soon as the rate of O2 delivery ( [Formula: see text] ) drops below a "critical level", a response accounted for by the reduction in mitochondrial O2supply. In urethane-anesthetized rats, [Formula: see text] was decreased within 20min from 21.5 to 2.8mlmin(-1) by slowly withdrawing 18mlkg(-1) of blood. This led to a reduction in [Formula: see text] from 6.1 to 2.4mlmin(-1) (n=5, p<0.01). Decoupling mitochondrial oxidative activity by injecting 2,4-DNP (6mgkg(-1), iv) before HS elevated [Formula: see text] to 11.9±1.2mlmin(-1) (n=6, p<0.01), which remained above control HS values throughout most of the hemorrhage. This was associated with higher levels of O2 extraction, cardiac output and ventilation than in control HS. [Formula: see text] relationship was shifted upward and to the left following DNP. In conclusion, cellular and systemic mechanisms, decreasing O2demand, account for a large part of HS induced [Formula: see text] decline resulting in an additional reduction in [Formula: see text] .
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Affiliation(s)
- Philippe Haouzi
- Pennsylvania State University, College of Medicine, Division of Pulmonary and Critical Care Medicine, Penn State Hershey Medical Center, Hershey, PA, United States.
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Yan W, Liu J. Effects of Chinese herbal monomers on oxidative phosphorylation and membrane potential in cerebral mitochondria isolated from hypoxia-exposed rats in vitro. Neural Regen Res 2012; 7:2099-106. [PMID: 25558222 PMCID: PMC4281410 DOI: 10.3969/j.issn.1673-5374.2012.27.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 07/18/2012] [Indexed: 02/04/2023] Open
Abstract
Mitochondrial dysfunction is the key pathogenic mechanism of cerebral injury induced by high-altitude hypoxia. Some Chinese herbal monomers may exert anti-hypoxic effects through enhancing the efficiency of oxidative phosphorylation. In this study, effects of 10 kinds of Chinese herbal monomers on mitochondrial respiration and membrane potential of cerebral mitochondria isolated from hypoxia-exposed rats in vitro were investigated to screen anti-hypoxic drugs. Rats were exposed to a low-pressure environment of 405.35 mm Hg (54.04 kPa) for 3 days to establish high-altitude hypoxic models. Cerebral mitochondria were isolated and treated with different concentrations of Chinese herbal monomers (sinomenine, silymarin, glycyrrhizic acid, baicalin, quercetin, ginkgolide B, saffron, piperine, ginsenoside Rg1 and oxymatrine) for 5 minutes in vitro. Mitochondrial oxygen consumption and membrane potential were measured using a Clark oxygen electrode and the rhodamine 123 fluorescence analysis method, respectively. Hypoxic exposure significantly decreased the state 3 respiratory rate, respiratory control rate and mitochondrial membrane potential, and significantly increased the state 4 respiratory rate. Treatment with saffron, ginsenoside Rg1 and oxymatrine increased the respiratory control rate in cerebral mitochondria isolated from hypoxia-exposed rats in dose-dependent manners in vitro, while ginsenoside Rg1, piperine and oxymatrine significantly increased the mitochondrial membrane potential in cerebral mitochondria from hypoxia-exposed rats. The Chinese herbal monomers saffron, ginsenoside Rg1, piperine and oxymatrine could thus improve cerebral mitochondrial disorders in oxidative phosphorylation induced by hypobaric hypoxia exposure in vitro.
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Affiliation(s)
- Weihua Yan
- Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine, the Third Military Medical University of Chinese PLA, Chongqing 400038, China ; Key Laboratory of High Altitude Medicine, Ministry of Education, Chongqing 400038, China ; Key Laboratory of High Altitude Physiology and High Altitude Disease of Chinese PLA, Chongqing 400038, China
| | - Junze Liu
- Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine, the Third Military Medical University of Chinese PLA, Chongqing 400038, China ; Key Laboratory of High Altitude Medicine, Ministry of Education, Chongqing 400038, China ; Key Laboratory of High Altitude Physiology and High Altitude Disease of Chinese PLA, Chongqing 400038, China
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Haouzi P, Van de Louw A. Metabolic and ventilatory depression in rat. J Appl Physiol (1985) 2012; 113:514; author reply 515. [DOI: 10.1152/japplphysiol.00615.2012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Philippe Haouzi
- Pennsylvania State University, College of Medicine, Division of Pulmonary and Critical Care Medicine, Penn State Hershey Medical Center, Hershey, Pennsylvania
| | - Andry Van de Louw
- Pennsylvania State University, College of Medicine, Division of Pulmonary and Critical Care Medicine, Penn State Hershey Medical Center, Hershey, Pennsylvania
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CHARVÁTOVÁ Z, OŠŤÁDALOVÁ I, ZICHA J, KUNEŠ J, MAXOVÁ H, OŠŤÁDAL B. Cardiac Tolerance to Ischemia in Neonatal Spontaneously Hypertensive Rats. Physiol Res 2012; 61:S145-53. [DOI: 10.33549/physiolres.932368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Hypertension is the risk factor of serious cardiovascular diseases, such as ischemic heart disease and atherosclerosis. The aim of the present study was to analyze the development of cardiac tolerance to ischemia in neonatal spontaneously hypertensive rats (SHR) and possible protective effect of ischemic preconditioning (IP) or adaptation to intermittent high-altitude hypoxia (IHAH). For this purpose we used 1- and 10-day-old pups of SHR and their normotensive control Wistar Kyoto rats (WKY). Isolated hearts were perfused in the Langendorff mode with Krebs-Henseleit solution at constant pressure, temperature and rate. Cardiac tolerance to ischemia was expressed as a percentage of baseline values of developed force (DF) after global ischemia. IP was induced by three 3-min periods of global ischemia, each separated by 5-min periods of reperfusion. IHAH was simulated in barochamber (8 h/day, 5000 m) from postnatal day 1 to 10. Cardiac tolerance to ischemia in 1-day-old SHR was higher than in WKY. In both strains tolerance decreased after birth, and the difference disappeared. The high cardiac resistance in 1- and 10-day-old SHR and WKY could not be further increased by both IP and adaptation to IHAH. It may be concluded that hearts from newborn SHR are more tolerant to ischemia/reperfusion injury as compared to age-matched WKY; cardiac resistance decreased in both strains during the first ten days, similarly as in Wistar rats.
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Affiliation(s)
- Z. CHARVÁTOVÁ
- Centre for Cardiovascular Research, Prague, Czech Republic, Department of Pathophysiology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
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Druyan S, Levi E, Shinder D, Stern T. Reduced O2 concentration during CAM development—Its effect on physiological parameters of broiler embryos. Poult Sci 2012; 91:987-97. [DOI: 10.3382/ps.2011-01727] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Baze MM, Hunter K, Hayes JP. Chronic hypoxia stimulates an enhanced response to immune challenge without evidence of an energetic tradeoff. ACTA ACUST UNITED AC 2012; 214:3255-68. [PMID: 21900473 DOI: 10.1242/jeb.054544] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
There is broad interest in whether there is a tradeoff between energy metabolism and immune function, and how stress affects immune function. Under hypoxic stress, maximal aerobic metabolism is limited, and other aspects of energy metabolism of animals may be altered as well. Although acute hypoxia appears to enhance certain immune responses, the effects of chronic hypoxia on immune function are largely unstudied. We tested: (1) whether chronic hypoxia affects immune function and (2) whether hypoxia affects the metabolic cost of immune function. First, flow cytometry was used to monitor the peripheral blood immunophenotype of mice over the course of 36 days of hypoxic exposure. Second, hypoxic and normoxic mice were subjected to an adaptive immune challenge via keyhole limpet hemocyanin (KLH) or to an innate immune challenge via lipopolysaccharide (LPS). The resting metabolic rates of mice in all immune challenge treatments were also measured. Although hypoxia had little effect on the peripheral blood immunophenotype, hypoxic mice challenged with KLH or LPS had enhanced immunological responses in the form of higher antibody titers or increased TNF-α production, respectively. Initially, mice exposed to hypoxia had lower metabolic rates, but this response was transitory and resting metabolic rates were normal by the end of the experiment. There was no effect of either immune challenge on resting metabolic rate, suggesting that mounting either the acute phase response or a humoral response is not as energetically expensive as previously thought. In addition, our results suggest that immune responses to chronic and acute hypoxia are concordant. Both forms of hypoxia appear to stimulate both innate and adaptive immune responses.
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Affiliation(s)
- Monica M Baze
- Program in Ecology, Evolution and Conservation Biology and Department of Biology, University of Nevada, Reno, NV 89557, USA.
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Abstract
INTRODUCTION Access to genetically engineered mice has opened many new opportunities to address questions relevant to the pathophysiology and treatment of patients in critical conditions. However, the results of studies in mice cannot disregard the unique ability of small rodents to adjust their temperature and high metabolic rate and the corresponding respiratory and circulatory requirements in response to hypoxia. POINT OF VIEW Studies performed in mice on questions related to metabolic, circulatory, and respiratory regulation should always be considered in light of the ability of mice to rapidly drop their nonshivering thermogenesis-related metabolism. As an example, it has been recently argued that a moderate level of inhaled hydrogen sulfide may have a potential benefit in patients in coma or shock or during an anoxic or ischemic insult, as this toxic gas dramatically reduces the metabolic rate in resting mice. However, acute hypometabolism has long been described in small mammals in response to hypoxia and is not specific to hydrogen sulfide. More importantly, mice have a specific metabolic rate that is 15-20 times higher than the specific metabolic level of a resting human. This difference can be accounted for by the large amount of heat produced by mice through nonshivering thermogenesis, related to the activity of uncoupling proteins. This mechanism, which is essential for maintaining homeothermia in small mammals, is virtually absent in larger animals, including in adult humans. Accordingly, no direct metabolic effect of hydrogen sulfide is observed in large mammals. We present the view that similar reasoning should be applied when the circulatory or respiratory response to hypoxic exposure is considered. This leads us to question whether a similar strategy could occur in mice in critical conditions other than hypoxia, such as in hypovolemic, septic, or cardiogenic shock. CONCLUSION Mouse models developed to understand the mechanisms of protection against hypoxia or ischemia or to propose new therapeutic approaches applicable in critical care patients should be understood in light of the specificity of the metabolic, respiratory, and circulatory responses of mice to a hypoxic insult, since many of these adaptations have no clear equivalent in humans.
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Schneider H. Oxygenation of the placental–fetal unit in humans. Respir Physiol Neurobiol 2011; 178:51-8. [DOI: 10.1016/j.resp.2011.05.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/22/2011] [Accepted: 05/11/2011] [Indexed: 01/18/2023]
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Le Prell CG, Dolan DF, Bennett DC, Boxer PA. Nutrient plasma levels achieved during treatment that reduces noise-induced hearing loss. Transl Res 2011; 158:54-70. [PMID: 21708356 PMCID: PMC3125531 DOI: 10.1016/j.trsl.2011.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 10/18/2022]
Abstract
Hearing loss encompasses both temporary and permanent deficits. If temporary threshold shift (TTS) and permanent threshold shift (PTS) share common pathological mechanisms, then agents that reduce PTS also should reduce TTS. Several antioxidant agents have reduced PTS in rodent models; however, reductions in TTS have been inconsistent. This study first determined whether dietary antioxidants (beta-carotene and vitamins C and E) delivered in combination with magnesium (Mg) reliably increase plasma concentrations of the active agents. Then, additional manipulations tested the hypothesis that these nutrients reduce acute TTS insult in the first 24 h after loud sound as well as longer lasting changes in hearing measured up to 7 days postnoise. Saline or nutrients were administered to guinea pigs prior to and after noise exposure. Sound-evoked electrophysiological responses were measured before noise, with tests repeated 1-h postnoise, as well as 1-day, 3-days, 5-days, and 7-days postnoise. All subjects showed significant functional recovery; subjects treated with nutrients recovered more rapidly and had better hearing outcomes at early postnoise times as well as the final test time. Thus, this combination of nutrients, which produced significant increases in plasma concentrations of vitamins C and E and Mg, effectively reduced hearing loss at multiple postnoise times. These data suggest that free radical formation contributes to TTS as well as PTS insults and suggest a potential opportunity to prevent TTS in human populations.
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Affiliation(s)
- Colleen G Le Prell
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL 32610, USA.
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Derwall M, Francis RCE, Kida K, Bougaki M, Crimi E, Adrie C, Zapol WM, Ichinose F. Administration of hydrogen sulfide via extracorporeal membrane lung ventilation in sheep with partial cardiopulmonary bypass perfusion: a proof of concept study on metabolic and vasomotor effects. Crit Care 2011; 15:R51. [PMID: 21299857 PMCID: PMC3221981 DOI: 10.1186/cc10016] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/15/2010] [Accepted: 02/07/2011] [Indexed: 11/28/2022] Open
Abstract
Introduction Although inhalation of 80 parts per million (ppm) of hydrogen sulfide (H2S) reduces metabolism in mice, doses higher than 200 ppm of H2S were required to depress metabolism in rats. We therefore hypothesized that higher concentrations of H2S are required to reduce metabolism in larger mammals and humans. To avoid the potential pulmonary toxicity of H2S inhalation at high concentrations, we investigated whether administering H2S via ventilation of an extracorporeal membrane lung (ECML) would provide means to manipulate the metabolic rate in sheep. Methods A partial venoarterial cardiopulmonary bypass was established in anesthetized, ventilated (fraction of inspired oxygen = 0.5) sheep. The ECML was alternately ventilated with air or air containing 100, 200, or 300 ppm H2S for intervals of 1 hour. Metabolic rate was estimated on the basis of total CO2 production (V˙CO2) and O2 consumption (V˙O2). Continuous hemodynamic monitoring was performed via indwelling femoral and pulmonary artery catheters. Results V˙CO2, V˙O2, and cardiac output ranged within normal physiological limits when the ECML was ventilated with air and did not change after administration of up to 300 ppm H2S. Administration of 100, 200 and 300 ppm H2S increased pulmonary vascular resistance by 46, 52 and 141 dyn·s/cm5, respectively (all P ≤ 0.05 for air vs. 100, 200 and 300 ppm H2S, respectively), and mean pulmonary artery pressure by 4 mmHg (P ≤ 0.05), 3 mmHg (n.s.) and 11 mmHg (P ≤ 0.05), respectively, without changing pulmonary capillary wedge pressure or cardiac output. Exposure to 300 ppm H2S decreased systemic vascular resistance from 1,561 ± 553 to 870 ± 138 dyn·s/cm5 (P ≤ 0.05) and mean arterial pressure from 121 ± 15 mmHg to 66 ± 11 mmHg (P ≤ 0.05). In addition, exposure to 300 ppm H2S impaired arterial oxygenation (PaO2 114 ± 36 mmHg with air vs. 83 ± 23 mmHg with H2S; P ≤ 0.05). Conclusions Administration of up to 300 ppm H2S via ventilation of an extracorporeal membrane lung does not reduce V˙CO2 and V˙O2, but causes dose-dependent pulmonary vasoconstriction and systemic vasodilation. These results suggest that administration of high concentrations of H2S in venoarterial cardiopulmonary bypass circulation does not reduce metabolism in anesthetized sheep but confers systemic and pulmonary vasomotor effects.
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Affiliation(s)
- Matthias Derwall
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
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Suspended animation inducer hydrogen sulfide is protective in an in vivo model of ventilator-induced lung injury. Intensive Care Med 2010; 36:1946-52. [PMID: 20721529 PMCID: PMC2952106 DOI: 10.1007/s00134-010-2022-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 07/12/2010] [Indexed: 01/10/2023]
Abstract
Purpose Acute lung injury is characterized by an exaggerated inflammatory response and a high metabolic demand. Mechanical ventilation can contribute to lung injury, resulting in ventilator-induced lung injury (VILI). A suspended-animation-like state induced by hydrogen sulfide (H2S) protects against hypoxia-induced organ injury. We hypothesized that suspended animation is protective in VILI by reducing metabolism and thereby CO2 production, allowing for a lower respiratory rate while maintaining adequate gas exchange. Alternatively, H2S may reduce inflammation in VILI. Methods In mechanically ventilated rats, VILI was created by application of 25 cmH2O positive inspiratory pressure (PIP) and zero positive end-expiratory pressure (PEEP). Controls were lung-protective mechanically ventilated (13 cmH2O PIP, 5 cmH2O PEEP). H2S donor NaHS was infused continuously; controls received saline. In separate control groups, hypothermia was induced to reproduce the H2S-induced fall in temperature. In VILI groups, respiratory rate was adjusted to maintain normo-pH. Results NaHS dose-dependently and reversibly reduced body temperature, heart rate, and exhaled amount of CO2. In VILI, NaHS reduced markers of pulmonary inflammation and improved oxygenation, an effect which was not observed after induction of deep hypothermia that paralleled the NaHS-induced fall in temperature. Both NaHS and hypothermia allowed for lower respiratory rates while maintaining gas exchange. Conclusions NaHS reversibly induced a hypometabolic state in anesthetized rats and protected from VILI by reducing pulmonary inflammation, an effect that was in part independent of body temperature. Electronic supplementary material The online version of this article (doi:10.1007/s00134-010-2022-2) contains supplementary material, which is available to authorized users.
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Forgan LG, Forster ME. Oxygen-dependence of metabolic rate in the muscles of craniates. J Comp Physiol B 2010; 180:715-29. [DOI: 10.1007/s00360-010-0455-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 02/04/2010] [Accepted: 02/07/2010] [Indexed: 10/19/2022]
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Szdzuy K, Zeller U. Lung and metabolic development in mammals: contribution to the reconstruction of the marsupial and eutherian morphotype. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2009; 312:555-78. [PMID: 18623108 DOI: 10.1002/jez.b.21228] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Marsupials represent only 6% of all living mammals. Marsupialia and Placentalia are distinguished mainly by their modes of reproduction. In particular, the differences in the stage of development of the neonates may be one explanation for the divergent evolutionary success. In this respect one important question is whether the survivability of the neonate depends on the degree of maturation of the respiratory system relative to the metabolic capacity at the time of birth. Therefore, this review highlights the differences in lung morphology and metabolic development of extant Marsupialia and Placentalia. The Marsupial neonate is born with a low birth weight and is highly immature. The neonatal lung is characterized by large terminal sacs, a poorly developed bronchial system and late formation of alveoli. Marsupialia have a low metabolic rate at birth and attain adult metabolic rate and thermoregulatory capacity late in postnatal development. In contrast, the eutherian neonate is born with a relative high birth weight and is always more mature than marsupial neonates. The neonatal lung has small terminal sacs, the bronchial system is well developed and the formation of alveoli begins few days after birth. Placentalia have a high metabolic rate at birth and attain adult metabolic rate and thermoregulatory capacity early in postnatal development. The differences in the developmental degree of the newborn lung between Marsupialia and Placentalia have consequences for their metabolic and thermoregulatory capacity. These differences could be advantageous for Placentalia in the changing environments in which they evolved.
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Affiliation(s)
- Kirsten Szdzuy
- Institute of Systematic Zoology, Museum of Natural History, Berlin, Germany.
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Schneider H. Tolerance of Human Placental Tissue to Severe Hypoxia and Its Relevance for Dual Ex Vivo Perfusion. Placenta 2009; 30 Suppl A:S71-6. [DOI: 10.1016/j.placenta.2008.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 11/05/2008] [Accepted: 11/07/2008] [Indexed: 11/26/2022]
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Later W, Bosy-Westphal A, Hitze B, Kossel E, Glüer CC, Heller M, Müller MJ. No evidence of mass dependency of specific organ metabolic rate in healthy humans. Am J Clin Nutr 2008; 88:1004-9. [PMID: 18842787 DOI: 10.1093/ajcn/88.4.1004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In humans, resting energy expenditure (REE) can be calculated from organ and tissue masses using constant specific organ metabolic rates. However, interspecies data suggest allometric relations between body mass and organ metabolic rate with higher specific metabolic rates in mammals with a smaller body mass. OBJECTIVE The objective was to compare the accuracy of REE prediction with the use of either constant or body mass-dependent specific organ metabolic rates. DESIGN Healthy subjects (79 women, 75 men) within the normal range of fat mass (FM) expected for a healthy body mass index and aged 18-78 y were stratified into tertiles of body mass. Fifty subjects were grouped as tertile 1 (<66.3 kg), 52 as tertile 2 (> or =66.3 to < or =77.2 kg), and 52 as tertile 3 (>77.2 kg). Magnetic resonance imaging was used to assess the volume of 4 internal organs (brain, heart, liver, and kidneys). REE was measured by indirect calorimetry (REE(m)) and compared with REE calculated from previously published constant (REE(c1)) and body mass-dependent organ metabolic rates (REE(c2)). RESULTS REE(m) increased significantly with weight tertile (tertile 1: 5536 +/- 529 kJ/d; tertile 2: 6389 +/- 672 kJ/d; tertile 3: 7467 +/- 745 kJ/d; P < 0.01). The deviation REE(m)-REE(c1) did not differ between weight tertiles (tertile 1: 66 +/- 382 kJ/d; tertile 2: 167 +/- 507 kJ/d; tertile 3: 86 +/- 480 kJ/d; NS) and showed no relation with body mass (r = -0.05, NS). By contrast, REE(m)-REE(c2) increased with increasing weight tertile (tertile 1: -45 +/- 369 kJ/d; tertile 2: 150 +/- 503 kJ/d; tertile 3: 193 +/- 482 kJ/d; P < 0.05) and correlated significantly with body mass (r = 0.16, P < 0.05). CONCLUSION Our data do not support a lower specific organ metabolic rate in humans with a larger body mass than in those with a smaller body mass.
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Affiliation(s)
- Wiebke Later
- Institute of Human Nutrition and Food Science, Christian-Albrechts University, Kiel, Germany
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Abstract
Homeothermy is the result of an evolutionary process during which every increase in oxygen supply led to a consecutive increase in metabolic rate and, thus, to a new dependence on favorable ambient conditions. In response to the food scarcity of winter months, some inhabitants of temperate zones developed an ability to hibernate which is characterized by a fully thermocontrolled reduction in body temperature down to near zero values. Hibernation thus illustrates that in homeotherms, not only the body shell is poikilothermic, but also the core temperature is more variable than often assumed. However, in contrast to clinical hypothermia, natural torpidity does not consist of a cold-induced reduction in metabolic rate, but of an endogenous metabolic reduction with subsequent lowering of body temperature. As a factor of metabolic suppression, the pH has been suspected which, in hibernators, is kept constant at 7.4 by relative hypoventilation (pH-stat) which differs from its passive shift in the poikilothermic body shell (alpha-stat). In clinical hypothermia, temperature governs the metabolic rate in that, depending on the state of thermoregulation, either a cold defense reaction with an increased metabolic rate (accidental hypothermia) or a cold-induced reduction in metabolic rate (induced hypothermia) occurs. However, as can be learned from hibernators, the lower limit of hypothermia tolerance seems to be due to a uniform minimal metabolic rate rather than to the species-specific body temperature at which this metabolic limit is reached, depending on body size and basal metabolic rate. Accordingly, in judging the sequelae of hypothermia, the degree of cooling should be given less emphasis than the resulting effects on metabolic rate.
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Affiliation(s)
- D Singer
- Sektion Neonatologie und Pädiatrische Intensivmedizin, Zentrum Frauen-, Kinder- und Jugendmedizin, Universitätsklinikum Eppendorf, Martinistr. 52, 20246 Hamburg.
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H2S induced hypometabolism in mice is missing in sedated sheep. Respir Physiol Neurobiol 2008; 160:109-15. [DOI: 10.1016/j.resp.2007.09.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 08/29/2007] [Accepted: 09/10/2007] [Indexed: 11/19/2022]
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Szdzuy K, Zeller U, Renfree M, Tzschentke B, Janke O. Postnatal lung and metabolic development in two marsupial and four eutherian species. J Anat 2007; 212:164-79. [PMID: 18179474 DOI: 10.1111/j.1469-7580.2007.00849.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Two marsupial species (Monodelphis domestica, Macropus eugenii) and four eutherian species (Mesocricetus auratus, Suncus murinus, Tupaia belangeri and Cavia aperea) were examined to compare and contrast the timing of lung and metabolic development during the postnatal maturation of the mammalian respiratory apparatus. Using light, scanning and transmission electron microscopy, the lung structural changes were correlated with indirect calorimetry to track the metabolic development. Marsupial and eutherian species followed the same pattern of mammalian lung development, but differed in the developmental pace. In the two newborn marsupial species, the lung parenchyma was at the early terminal sac stage, with large terminal air sacs, and the lung developed slowly. In contrast, the newborn eutherian species had more advanced lungs at the late terminal sac stage in altricial species (M. auratus, S. murinus) and at the alveolar stage in precocial species (T. belangeri, C. aperea). Postnatal lung development proceeded rapidly in eutherian species. The marsupial species had a low metabolic rate at birth and achieved adult metabolism late in postnatal development. In contrast, newborn eutherian species had high metabolic rates and reached adult metabolism during the first week of life. The time course of the metabolic development is thus tightly linked to the structural differentiation of the lungs and the timing of postnatal lung development. These differences in the neonatal lung structure and the timing of postnatal lung maturation between marsupial and eutherian species reflect their differing reproductive strategies.
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Affiliation(s)
- Kirsten Szdzuy
- Institute of Systematic Zoology, Museum of Natural History, Berlin, Germany.
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Singer D, Mühlfeld C. Perinatal adaptation in mammals: the impact of metabolic rate. Comp Biochem Physiol A Mol Integr Physiol 2007; 148:780-4. [PMID: 17561425 DOI: 10.1016/j.cbpa.2007.05.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2007] [Revised: 05/02/2007] [Accepted: 05/03/2007] [Indexed: 11/26/2022]
Abstract
Mammalian birth is accompanied by profound changes in metabolic rate that can be described in terms of body size relationship (Kleiber's rule). Whereas the fetus, probably as an adaptation to the low intrauterine pO2, exhibits an "inappropriately" low, adult-like specific metabolic rate, the term neonate undergoes a rapid metabolic increase up to the level to be expected from body size. A similar, albeit slowed, "switching-on" of metabolic size allometry is found in human preterm neonates whereas animals that are normally born in a very immature state are able to retard or even suppress the postnatal metabolic increase in favor of weight gain and O2 supply. Moreover, small immature mammalian neonates exhibit a temporary oxyconforming behavior which enhances their hypoxia tolerance, yet is lost to the extent by which the size-adjusted metabolic rate is "locked" by increasing mitochondrial density. Beyond the perinatal period, there are no other deviations from metabolic size allometry among mammals except in hibernation where the temporary "switching-off" of Kleiber's rule is accompanied by a deep reduction in tissue pO2. This gives support to the hypothesis that the postnatal metabolic increase represents an "escape from oxygen" similar to the evolutionary roots of mitochondrial respiration, and that the overall increase in specific metabolic rate with decreasing size might contribute to prevent tissues from O2 toxicity.
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Affiliation(s)
- Dominique Singer
- Section for Neonatology and Pediatric Intensive Care Medicine, Center of Gynecology, Obstetrics, and Pediatrics, University Clinics Eppendorf, 20246 Hamburg, Germany.
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Mühlfeld C, Singer D, Engelhardt N, Richter J, Schmiedl A. Electron microscopy and microcalorimetry of the postnatal rat heart (Rattus norvegicus). Comp Biochem Physiol A Mol Integr Physiol 2005; 141:310-8. [PMID: 15993636 DOI: 10.1016/j.cbpb.2005.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 05/31/2005] [Accepted: 06/01/2005] [Indexed: 11/15/2022]
Abstract
The interplay of ultrastructure and tissue metabolism was examined in neonatal, infant and adult rat hearts by electron microscopy and microcalorimetry. Morphometry was used to determine parameters of oxygen diffusion capacity (distance between capillaries and mitochondria, capillary surface density) and oxidative metabolic capacity (mitochondrial volume fraction). Thin slices and large samples of living tissue were examined calorimetrically to quantify aerobic metabolism and ischemia tolerance, respectively. After birth, rat hearts grow in parallel to body mass and show characteristics of cellular hypertrophy. Capillary surface density increases from neonatal to infant rats, and decreases to an intermediate value in adult rats. The distance between capillaries and mitochondria shows no significant changes throughout postnatal development. Mitochondrial volume fraction increases continuously until adulthood. The specific aerobic tissue metabolic rate is higher in the neonatal than in the infant and adult rat. However, the ischemic decline in metabolic rate is much slower in the neonatal rat, reflecting an elevated hypoxia tolerance. In conclusion, the neonatal rat heart exhibits a high metabolic rate despite a low mitochondrial volume fraction. The subsequent structural rearrangements can be interpreted as long-term adaptations to the increased postnatal workload and may contribute to the progressive loss of hypoxia tolerance.
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Affiliation(s)
- C Mühlfeld
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Germany.
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