1
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Ojaghi M, Pamenter ME. Hypoxia impairs blood glucose homeostasis in naked mole-rat adult subordinates but not queens. J Exp Biol 2024; 227:jeb247537. [PMID: 38680085 PMCID: PMC11166464 DOI: 10.1242/jeb.247537] [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: 02/16/2024] [Accepted: 04/12/2024] [Indexed: 05/01/2024]
Abstract
Naked mole-rats (NMRs) are among the most hypoxia-tolerant mammals and metabolize only carbohydrates in hypoxia. Glucose is the primary building block of dietary carbohydrates, but how blood glucose is regulated during hypoxia has not been explored in NMRs. We hypothesized that NMRs mobilize glucose stores to support anaerobic energy metabolism in hypoxia. To test this, we treated newborn, juvenile and adult (subordinate and queen) NMRs in normoxia (21% O2) or hypoxia (7, 5 or 3% O2), while measuring metabolic rate, body temperature and blood [glucose]. We also challenged animals with glucose, insulin or insulin-like growth factor-1 (IGF-1) injections and measured the rate of glucose clearance in normoxia and hypoxia. We found that: (1) blood [glucose] increases in moderate hypoxia in queens and pups, but only in severe hypoxia in adult subordinates and juveniles; (2) glucose tolerance is similar between developmental stages in normoxia, but glucose clearance times are 2- to 3-fold longer in juveniles and subordinates than in queens or pups in hypoxia; and (3) reoxygenation accelerates glucose clearance in hypoxic subordinate adults. Mechanistically, (4) insulin and IGF-1 reduce blood [glucose] in subordinates in both normoxia but only IGF-1 impacts blood [glucose] in hypoxic queens. Our results indicate that insulin signaling is impaired by hypoxia in NMRs, but that queens utilize IGF-1 to overcome this limitation and effectively regulate blood glucose in hypoxia. This suggests that sexual maturation impacts blood glucose handling in hypoxic NMR queens, which may allow queens to spend longer periods of time in hypoxic nest chambers.
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Affiliation(s)
- Mohammad Ojaghi
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 9A7
| | - Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 9A7
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada, K1H 8M5
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2
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Kadamani KL, Logan SM, Pamenter ME. Does hypometabolism constrain innate immune defense? Acta Physiol (Oxf) 2024; 240:e14091. [PMID: 38288574 DOI: 10.1111/apha.14091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 11/30/2023] [Accepted: 01/01/2024] [Indexed: 02/24/2024]
Abstract
Many animals routinely make energetic trade-offs to adjust to environmental demands and these trade-offs often have significant implications for survival. For example, environmental hypoxia is commonly experienced by many organisms and is an energetically challenging condition because reduced oxygen availability constrains aerobic energy production, which can be lethal. Many hypoxia-tolerant species downregulate metabolic demands when oxygen is limited; however, certain physiological functions are obligatory and must be maintained despite the need to conserve energy in hypoxia. Of particular interest is immunity (including both constitutive and induced immune functions) because mounting an immune response is among the most energetically expensive physiological processes but maintaining immune function is critical for survival in most environments. Intriguingly, physiological responses to hypoxia and pathogens share key molecular regulators such as hypoxia-inducible factor-1α, through which hypoxia can directly activate an immune response. This raises an interesting question: do hypoxia-tolerant species mount an immune response during periods of hypoxia-induced hypometabolism? Unfortunately, surprisingly few studies have examined interactions between immunity and hypometabolism in such species. Therefore, in this review, we consider mechanistic interactions between metabolism and immunity, as well as energetic trade-offs between these two systems, in hypoxia-tolerant animals but also in other models of hypometabolism, including neonates and hibernators. Specifically, we explore the hypothesis that such species have blunted immune responses in hypometabolic conditions and/or use alternative immune pathways when in a hypometabolic state. Evidence to date suggests that hypoxia-tolerant animals do maintain immunity in low oxygen conditions, but that the sensitivity of immune responses may be blunted.
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Affiliation(s)
- Karen L Kadamani
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Samantha M Logan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, Ontario, Canada
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3
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Kawamura M, Yoshimoto A, Ikegaya Y, Matsumoto N. Low Atmospheric Oxygen Attenuates Alpha Oscillations in the Primary Motor Cortex of Awake Rats. Biol Pharm Bull 2024; 47:462-468. [PMID: 38382999 DOI: 10.1248/bpb.b23-00863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Oxygen is pivotal for survival of animals. Their cellular activity and cognitive behavior are impaired when atmospheric oxygen is insufficient, called hypoxia. However, concurrent effects of hypoxia on physiological signals are poorly understood. To address this question, we simultaneously recorded local field potentials in the primary motor cortex, primary somatosensory, and anterior cingulate cortex, electrocardiograms, electroolfactograms, and electromyograms of rats under acute hypoxic conditions (i.e., 5.0% O2). Exposure to acute hypoxia significantly attenuated alpha oscillations alone in the primary motor cortex, while we failed to find any effects of acute hypoxia on the oscillatory power in the somatosensory cortex or anterior cingulate cortex. These area- and frequency-specific effects by hypoxia may be accounted for by neural innervation from the brainstem to each cortical area via thalamic relay nuclei. Moreover, we found that heart rate and respiratory rate were increased during acute hypoxia and high heart rate was maintained even after the oxygen level returned to the baseline. Altogether, our study characterizes a systemic effect of atmospheric hypoxia on neural and peripheral signals from physiological viewpoints, leading to bridging a gap between cellular and behavioral levels.
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Affiliation(s)
- Masashi Kawamura
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Airi Yoshimoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
- Institute for AI and Beyond, The University of Tokyo
- Center for Information and Neural Networks, National Institute of Information and Communications Technology
| | - Nobuyoshi Matsumoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
- Institute for AI and Beyond, The University of Tokyo
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4
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Devereaux MEM, Chiasson S, Brennan KF, Pamenter ME. The glutamatergic drive to breathe is reduced in severe but not moderate hypoxia in Damaraland mole-rats. J Exp Biol 2023; 226:jeb246185. [PMID: 37589556 PMCID: PMC10565110 DOI: 10.1242/jeb.246185] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/07/2023] [Indexed: 08/18/2023]
Abstract
Damaraland mole-rats (Fukomys damarensis) are a hypoxia-tolerant fossorial species that exhibit a robust hypoxic metabolic response (HMR) and blunted hypoxic ventilatory response (HVR). Whereas the HVR of most adult mammals is mediated by increased excitatory glutamatergic signalling, naked mole-rats, which are closely related to Damaraland mole-rats, do not utilize this pathway. Given their phylogenetic relationship and similar lifestyles, we hypothesized that the signalling mechanisms underlying physiological responses to acute hypoxia in Damaraland mole-rats are like those of naked mole-rats. To test this, we used pharmacological antagonists of glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and N-methyl-d-aspartate receptors (NMDARs), combined with plethysmography, respirometry and thermal RFID chips, to non-invasively evaluate the role of excitatory AMPAR and NMDAR signalling in mediating ventilatory, metabolic and thermoregulatory responses, respectively, to 1 h of 5 or 7% O2. We found that AMPAR or NMDAR antagonism have minimal impacts on the HMR or hypoxia-mediated changes in thermoregulation. Conversely, the 'blunted' HVR of Damaraland mole-rats is reduced by either AMPAR or NMDAR antagonism such that the onset of the HVR occurs in less severe hypoxia. In more severe hypoxia, antagonists have no impact, suggesting that these receptors are already inhibited. Together, these findings indicate that the glutamatergic drive to breathe decreases in Damaraland mole-rats exposed to severe hypoxia. These findings differ from other adult mammals, in which the glutamatergic drive to breathe increases with hypoxia.
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Affiliation(s)
| | - Sarah Chiasson
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Kate F. Brennan
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H 8M5, Canada
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5
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Pan D, Wang J, Li M, Qiao C, Zhang Y, Shao T, Sun H, Wang Z. Changes in gene expression and enzyme activity related to glucose metabolism in the livers of Brandt's voles (Lasiopodomys brandtii) exposed to hypoxia. Comp Biochem Physiol A Mol Integr Physiol 2023; 279:111384. [PMID: 36738876 DOI: 10.1016/j.cbpa.2023.111384] [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: 07/19/2022] [Revised: 01/30/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
Brandt's vole (Lasiopodomys brandtii) is a hypoxia-tolerant species, and the metabolic characteristics of hypoxia-tolerant species have become a focus of recent research. However, insights into the anaerobic and aerobic metabolism of the livers of Brandt's voles under hypoxia remain limited. In this study, Brandt's voles and hypoxia-intolerant Kunming mice (Mus musculus, control species) were exposed to hypoxia conditions (Brandt's voles, 10% and 7.5% O2; Kunming mice, 10% O2) for 24 h, and changes in gene expression and enzyme activity related to anaerobic and aerobic metabolism in the livers were evaluated. Phosphofructokinase 1 (PFK1), phosphofructokinase 2 (PFK2), pyruvate kinase muscle (PKM), hexokinase 2 (HK2), and lactate dehydrogenase (LDH) related to anaerobic metabolism in the livers of Brandt's voles were increased under 7.5% O2. Regarding gene expression and enzyme activity for aerobic metabolism in Brandt's voles under 7.5% and 10% O2, pyruvate dehydrogenase kinase 1 (PDK1) expression was up-regulated, and succinate dehydrogenase (SDH) activity was decreased. In the livers of Kunming mice, gene expression related to anaerobic and aerobic metabolism was increased at the late stage of 10% O2, and SDH activity was enhanced at 6 h and reduced at 18 h. In addition, PFK1,PKM, PDK1 expression and SDH activity in Brandt's voles were significantly correlated with HIF-1a expression. PFK1, PKM, LDHand PDK1 expression in Kunming mice were significantly correlated with HIF-1a expression. These findings indicate that the livers of Brandt's voles have a certain tolerance to hypoxia, and metabolic changes play important roles in hypoxia tolerance.
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Affiliation(s)
- Dan Pan
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China
| | - Jingou Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China
| | - Mengke Li
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China
| | - Congcong Qiao
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China
| | - Yifeng Zhang
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China
| | - Tian Shao
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China
| | - Hong Sun
- Centre for Nutritional Ecology, Zhengzhou University, Zhengzhou, Henan Province, PR China.
| | - Zhenlong Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan Province, PR China.
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Marks de Chabris NC, Sabir S, Perkins G, Cheng H, Ellisman MH, Pamenter ME. Short communication: Acute hypoxia does not alter mitochondrial abundance in naked mole-rats. Comp Biochem Physiol A Mol Integr Physiol 2023; 276:111343. [PMID: 36379380 DOI: 10.1016/j.cbpa.2022.111343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/20/2022] [Accepted: 11/08/2022] [Indexed: 11/15/2022]
Abstract
Hypoxia poses a significant energetic challenge and most species exhibit metabolic remodelling when exposed to prolonged hypoxia. One component of this remodelling is mitochondrial biogenesis/mitophagy, which alter mitochondrial abundance and helps to adjust metabolic throughput to match changes in energy demands in hypoxia. However, how acute hypoxia impacts mitochondrial abundance in hypoxia-tolerant species is poorly understood. To help address this gap, we exposed hypoxia-tolerant naked mole-rats to 3 h of normoxia or acute hypoxia (5% O2) and measured changes in mitochondrial abundance using two well-established markers: citrate synthase (CS) enzyme activity and mitochondrial DNA (mtDNA) abundance. We found that neither marker changed with hypoxia in brain, liver, or kidney, suggesting that mitochondrial biogenesis is not initiated during acute hypoxia in these tissues. Conversely in skeletal muscle, the ratio of CS activity to total protein decreased 50% with hypoxia. However, this change was likely driven by an increase in soluble protein density in hypoxia because CS activity was unchanged relative to wet tissue weight and the mtDNA copy number was unchanged. To confirm this, we examined skeletal muscle mitochondria using transmission electron microscopy and found no change in mitochondrial volume density. Taken together with previous studies of mitochondrial respiratory function, our present findings suggest that naked mole-rats primarily rely on tissue-specific functional remodelling of metabolic pathways and mitochondrial respiratory throughput, and not physical changes in mitochondrial number or volume, to adjust to short-term hypoxic exposure.
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Affiliation(s)
| | - Soulene Sabir
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Guy Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Hang Cheng
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Marc H Ellisman
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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7
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Extracellular Vesicles in Veterinary Medicine. Animals (Basel) 2022; 12:ani12192716. [PMID: 36230457 PMCID: PMC9559303 DOI: 10.3390/ani12192716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/23/2022] [Accepted: 10/03/2022] [Indexed: 11/16/2022] Open
Abstract
Extracellular vesicles (EVs) are cell-derived membrane-bound vesicles involved in many physiological and pathological processes not only in humans but also in all the organisms of the eukaryotic and prokaryotic kingdoms. EV shedding constitutes a fundamental universal mechanism of intra-kingdom and inter-kingdom intercellular communication. A tremendous increase of interest in EVs has therefore grown in the last decades, mainly in humans, but progressively also in animals, parasites, and bacteria. With the present review, we aim to summarize the current status of the EV research on domestic and wild animals, analyzing the content of scientific literature, including approximately 220 papers published between 1984 and 2021. Critical aspects evidenced through the veterinarian EV literature are discussed. Then, specific subsections describe details regarding EVs in physiology and pathophysiology, as biomarkers, and in therapy and vaccines. Further, the wide area of research related to animal milk-derived EVs is also presented in brief. The numerous studies on EVs related to parasites and parasitic diseases are excluded, deserving further specific attention. The literature shows that EVs are becoming increasingly addressed in veterinary studies and standardization in protocols and procedures is mandatory, as in human research, to maximize the knowledge and the possibility to exploit these naturally produced nanoparticles.
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8
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Avoiding the effects of translocation on the estimates of the metabolic rates across an elevational gradient. J Comp Physiol B 2022; 192:659-668. [DOI: 10.1007/s00360-022-01448-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 05/30/2022] [Accepted: 06/24/2022] [Indexed: 10/17/2022]
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9
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Eaton L, Pamenter ME. What to do with low O 2: Redox adaptations in vertebrates native to hypoxic environments. Comp Biochem Physiol A Mol Integr Physiol 2022; 271:111259. [PMID: 35724954 DOI: 10.1016/j.cbpa.2022.111259] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 06/11/2022] [Accepted: 06/14/2022] [Indexed: 01/05/2023]
Abstract
Reactive oxygen species (ROS) are important cellular signalling molecules but sudden changes in redox balance can be deleterious to cells and lethal to the whole organism. ROS production is inherently linked to environmental oxygen availability and many species live in variable oxygen environments that can range in both severity and duration of hypoxic exposure. Given the importance of redox homeostasis to cell and animal viability, it is not surprising that early studies in species adapted to various hypoxic niches have revealed diverse strategies to limit or mitigate deleterious ROS changes. Although research in this area is in its infancy, patterns are beginning to emerge in the suites of adaptations to different hypoxic environments. This review focuses on redox adaptations (i.e., modifications of ROS production and scavenging, and mitigation of oxidative damage) in hypoxia-tolerant vertebrates across a range of hypoxic environments. In general, evidence suggests that animals adapted to chronic lifelong hypoxia are in homeostasis, and do not encounter major oxidative challenges in their homeostatic environment, whereas animals exposed to seasonal chronic anoxia or hypoxia rapidly downregulate redox balance to match a hypometabolic state and employ robust scavenging pathways during seasonal reoxygenation. Conversely, animals adapted to intermittent hypoxia exposure face the greatest degree of ROS imbalance and likely exhibit enhanced ROS-mitigation strategies. Although some progress has been made, research in this field is patchy and further elucidation of mechanisms that are protective against environmental redox challenges is imperative for a more holistic understanding of how animals survive hypoxic environments.
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Affiliation(s)
- Liam Eaton
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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10
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Acute pH alterations do not impact cardiac mitochondrial respiration in naked mole-rats or mice. Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111185. [PMID: 35278722 DOI: 10.1016/j.cbpa.2022.111185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/06/2022] [Accepted: 03/06/2022] [Indexed: 01/04/2023]
Abstract
Energetically demanding conditions such as hypoxia and exercise favour anaerobic metabolism (glycolysis), which leads to acidification of the cellular milieu from ATP hydrolysis and accumulation of the anaerobic end-product, lactate. Cellular acidification may damage mitochondrial proteins and/or alter the H+ gradient across the mitochondrial inner membrane, which may in turn impact mitochondrial respiration and thus aerobic ATP production. Naked mole-rats are among the most hypoxia-tolerant mammals, and putatively experience intermittent environmental and systemic hypoxia while resting and exercising in their underground burrows. Previous studies in naked mole-rat brain, heart, and skeletal muscle mitochondria have demonstrated adaptations that favour improved efficiency in hypoxic conditions; however, the impact of cellular acidification on mitochondrial function has not been explored. We hypothesized that, relative to hypoxia-intolerant mice, naked mole-rat cardiac mitochondrial respiration is less sensitive to cellular pH changes. To test this, we used high-resolution respirometry to measure mitochondrial respiration by permeabilized cardiac muscle fibres from naked mole-rats and mice exposed in vitro to a pH range from 6.6 to 7.6. Surprisingly, we found that acute pH changes do not impact cardiac mitochondrial respiration or compromise mitochondrial integrity in either species. Our results suggest that acute alterations of cellular pH have minimal impact on cardiac mitochondrial respiration.
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Inci N, Kamali D, Akyildiz EO, Tahir Turanli E, Bozaykut P. Translation of Cellular Senescence to Novel Therapeutics: Insights From Alternative Tools and Models. FRONTIERS IN AGING 2022; 3:828058. [PMID: 35821852 PMCID: PMC9261353 DOI: 10.3389/fragi.2022.828058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 04/12/2022] [Indexed: 01/10/2023]
Abstract
Increasing chronological age is the greatest risk factor for human diseases. Cellular senescence (CS), which is characterized by permanent cell-cycle arrest, has recently emerged as a fundamental mechanism in developing aging-related pathologies. During the aging process, senescent cell accumulation results in senescence-associated secretory phenotype (SASP) which plays an essential role in tissue dysfunction. Although discovered very recently, senotherapeutic drugs have been already involved in clinical studies. This review gives a summary of the molecular mechanisms of CS and its role particularly in the development of cardiovascular diseases (CVD) as the leading cause of death. In addition, it addresses alternative research tools including the nonhuman and human models as well as computational techniques for the discovery of novel therapies. Finally, senotherapeutic approaches that are mainly classified as senolytics and senomorphics are discussed.
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Affiliation(s)
- Nurcan Inci
- Graduate School of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Dilanur Kamali
- Graduate School of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Erdogan Oguzhan Akyildiz
- Graduate School of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Eda Tahir Turanli
- Graduate School of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Faculty of Engineering and Natural Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Perinur Bozaykut
- Graduate School of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Faculty of Engineering and Natural Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
- *Correspondence: Perinur Bozaykut,
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12
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Sandra I, Verri T, Filice M, Barca A, Schiavone R, Gattuso A, Cerra MC. Shaping the cardiac response to hypoxia: NO and its partners in teleost fish. Curr Res Physiol 2022; 5:193-202. [PMID: 35434651 PMCID: PMC9010694 DOI: 10.1016/j.crphys.2022.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 03/14/2022] [Accepted: 03/31/2022] [Indexed: 12/12/2022] Open
Abstract
The reduced availability of dissolved oxygen is a common stressor in aquatic habitats that affects the ability of the heart to ensure tissue oxygen supply. Among key signalling molecules activated during cardiac hypoxic stress, nitric oxide (NO) has emerged as a central player involved in the related adaptive responses. Here, we outline the role of the nitrergic control in modulating tolerance and adaptation of teleost heart to hypoxia, as well as major molecular players that participate in the complex NO network. The purpose is to provide a framework in which to depict how the heart deals with limitations in oxygen supply. In this perspective, defining the relational interplay between the multiple (sets of) proteins that, due to the gene duplication events that occurred during the teleost fish evolutive radiation, do operate in parallel with similar functions in the (different) heart (districts) and other body districts under low levels of oxygen supply, represents a next goal of the comparative research in teleost fish cardiac physiology. The flexibility of the teleost heart to O2 limitations is illustrated by using cyprinids as hypoxia tolerance models. Major molecular mediators of the teleost cardiac response are discussed with a focus on the nitrergic system. A comparative analysis of gene duplication highlights conserved targets which may orchestrate the cardiac response to hypoxia.
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Abstract
ABSTRACT
Hypoxia is one of the strongest environmental drivers of cellular and physiological adaptation. Although most mammals are largely intolerant of hypoxia, some specialized species have evolved mitigative strategies to tolerate hypoxic niches. Among the most hypoxia-tolerant mammals are naked mole-rats (Heterocephalus glaber), a eusocial species of subterranean rodent native to eastern Africa. In hypoxia, naked mole-rats maintain consciousness and remain active despite a robust and rapid suppression of metabolic rate, which is mediated by numerous behavioural, physiological and cellular strategies. Conversely, hypoxia-intolerant mammals and most other hypoxia-tolerant mammals cannot achieve the same degree of metabolic savings while staying active in hypoxia and must also increase oxygen supply to tissues, and/or enter torpor. Intriguingly, recent studies suggest that naked mole-rats share many cellular strategies with non-mammalian vertebrate champions of anoxia tolerance, including the use of alternative metabolic end-products and potent pH buffering mechanisms to mitigate cellular acidification due to upregulation of anaerobic metabolic pathways, rapid mitochondrial remodelling to favour increased respiratory efficiency, and systemic shifts in energy prioritization to maintain brain function over that of other tissues. Herein, I discuss what is known regarding adaptations of naked mole-rats to a hypoxic lifestyle, and contrast strategies employed by this species to those of hypoxia-intolerant mammals, closely related African mole-rats, other well-studied hypoxia-tolerant mammals, and non-mammalian vertebrate champions of anoxia tolerance. I also discuss the neotenic theory of hypoxia tolerance – a leading theory that may explain the evolutionary origins of hypoxia tolerance in mammals – and highlight promising but underexplored avenues of hypoxia-related research in this fascinating model organism.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 9A7. University of Ottawa, Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
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14
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Huynh KW, Pamenter ME. Lactate inhibits naked mole-rat cardiac mitochondrial respiration. J Comp Physiol B 2022; 192:501-511. [PMID: 35181821 DOI: 10.1007/s00360-022-01430-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/13/2022] [Accepted: 01/29/2022] [Indexed: 12/25/2022]
Abstract
In aerobic conditions, the proton-motive force drives oxidative phosphorylation (OXPHOS) and the conversion of ADP to ATP. In hypoxic environments, OXPHOS is impaired, resulting in energy shortfalls and the accumulation of protons and lactate. This results in cellular acidification, which may impact the activity and/or integrity of mitochondrial enzymes and in turn negatively impact mitochondrial respiration and thus aerobic ATP production. Naked mole-rats (NMRs) are among the most hypoxia-tolerant mammals and putatively experience intermittent hypoxia in their underground burrows. However, if and how NMR cardiac mitochondria are impacted by lactate accumulation in hypoxia is unknown. We predicted that lactate alters mitochondrial respiration in NMR cardiac muscle. To test this, we used high-resolution respirometry to measure mitochondrial respiration in permeabilized cardiac muscle fibres from NMRs exposed to 4 h of in vivo normoxia (21% O2) or hypoxia (7% O2). We found that: (1) cardiac mitochondria cannot directly oxidize lactate, but surprisingly, (2) lactate inhibits mitochondrial respiration, and (3) decreases complex IV maximum respiratory capacity. Finally, (4) in vivo hypoxic exposure decreases the magnitude of lactate-mediated inhibition of mitochondrial respiration. Taken together, our results suggest that lactate may retard electron transport system function in NMR cardiac mitochondria, particularly in normoxia, and that NMR hearts may be primed for anaerobic metabolism.
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Affiliation(s)
- Kenny W Huynh
- Department of Biology, University of Ottawa, 30 Marie Curie Pvt., Ottawa, ON, K1N 6N5, Canada
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, 30 Marie Curie Pvt., Ottawa, ON, K1N 6N5, Canada. .,University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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15
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Bishop M, Weinhold M, Turk AZ, Adeck A, SheikhBahaei S. An open-source tool for automated analysis of breathing behaviors in common marmosets and rodents. eLife 2022; 11:e71647. [PMID: 35049499 PMCID: PMC8856653 DOI: 10.7554/elife.71647] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
The respiratory system maintains homeostatic levels of oxygen (O2) and carbon dioxide (CO2) in the body through rapid and efficient regulation of breathing frequency and depth (tidal volume). The commonly used methods of analyzing breathing data in behaving experimental animals are usually subjective, laborious, and time-consuming. To overcome these hurdles, we optimized an analysis toolkit for the unsupervised study of respiratory activities in animal subjects. Using this tool, we analyzed breathing behaviors of the common marmoset (Callithrix jacchus), a New World non-human primate model. Using whole-body plethysmography in room air as well as acute hypoxic (10% O2) and hypercapnic (6% CO2) conditions, we describe breathing behaviors in awake, freely behaving marmosets. Our data indicate that marmosets' exposure to acute hypoxia decreased metabolic rate and increased sigh rate. However, the hypoxic condition did not augment ventilation. Hypercapnia, on the other hand, increased both the frequency and depth (i.e., tidal volume) of breathing.
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Affiliation(s)
- Mitchell Bishop
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, United States
| | - Maximilian Weinhold
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, United States
| | - Ariana Z Turk
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, United States
| | - Afuh Adeck
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, United States
| | - Shahriar SheikhBahaei
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, United States
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Li M, Pan D, Sun H, Zhang L, Cheng H, Shao T, Wang Z. The hypoxia adaptation of small mammals to plateau and underground burrow conditions. Animal Model Exp Med 2021; 4:319-328. [PMID: 34977483 PMCID: PMC8690988 DOI: 10.1002/ame2.12183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/08/2021] [Indexed: 12/19/2022] Open
Abstract
Oxygen is one of the important substances for the survival of most life systems on the earth, and plateau and underground burrow systems are two typical hypoxic environments. Small mammals living in hypoxic environments have evolved different adaptation strategies, which include increased oxygen delivery, metabolic regulation of physiological responses and other physiological responses that change tissue oxygen utilization. Multi-omics predictions have also shown that these animals have evolved different adaptations to extreme environments. In particular, vascular endothelial growth factor (VEGF) and erythropoietin (EPO), which have specific functions in the control of O2 delivery, have evolved adaptively in small mammals in hypoxic environments. Naked mole-rats and blind mole-rats are typical hypoxic model animals as they have some resistance to cancer. This review primarily summarizes the main living environment of hypoxia tolerant small mammals, as well as the changes of phenotype, physiochemical characteristics and gene expression mode of their long-term living in hypoxia environment.
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Affiliation(s)
- Mengke Li
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
| | - Dan Pan
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
| | - Hong Sun
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
- Centre for Nutritional EcologyZhengzhou UniversityZhengzhouP.R. China
| | - Lei Zhang
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
| | - Han Cheng
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
| | - Tian Shao
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
| | - Zhenlong Wang
- School of Life SciencesZhengzhou UniversityZhengzhouP.R. China
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17
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Cheng H, Sebaa R, Malholtra N, Lacoste B, El Hankouri Z, Kirby A, Bennett NC, van Jaarsveld B, Hart DW, Tattersall GJ, Harper ME, Pamenter ME. Naked mole-rat brown fat thermogenesis is diminished during hypoxia through a rapid decrease in UCP1. Nat Commun 2021; 12:6801. [PMID: 34815412 PMCID: PMC8610999 DOI: 10.1038/s41467-021-27170-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
Naked mole-rats are among the most hypoxia-tolerant mammals. During hypoxia, their body temperature (Tb) decreases via unknown mechanisms to conserve energy. In small mammals, non-shivering thermogenesis in brown adipose tissue (BAT) is critical to Tb regulation; therefore, we hypothesize that hypoxia decreases naked mole-rat BAT thermogenesis. To test this, we measure changes in Tb during normoxia and hypoxia (7% O2; 1-3 h). We report that interscapular thermogenesis is high in normoxia but ceases during hypoxia, and Tb decreases. Furthermore, in BAT from animals treated in hypoxia, UCP1 and mitochondrial complexes I-V protein expression rapidly decrease, while mitochondria undergo fission, and apoptosis and mitophagy are inhibited. Finally, UCP1 expression decreases in hypoxia in three other social African mole-rat species, but not a solitary species. These findings suggest that the ability to rapidly down-regulate thermogenesis to conserve oxygen in hypoxia may have evolved preferentially in social species.
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Affiliation(s)
- Hang Cheng
- grid.28046.380000 0001 2182 2255Department of Biology, University of Ottawa, Ottawa, ON Canada
| | - Rajaa Sebaa
- grid.28046.380000 0001 2182 2255Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON Canada ,grid.28046.380000 0001 2182 2255Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON Canada ,grid.449644.f0000 0004 0441 5692Department of Medical Laboratories, College of Applied Medical Sciences, University of Shaqra, Duwadimi, Saudi Arabia
| | - Nikita Malholtra
- grid.28046.380000 0001 2182 2255Department of Biology, University of Ottawa, Ottawa, ON Canada
| | - Baptiste Lacoste
- grid.28046.380000 0001 2182 2255Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON Canada ,grid.28046.380000 0001 2182 2255University of Ottawa Brain and Mind Research Institute, Ottawa, ON Canada ,grid.412687.e0000 0000 9606 5108Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - Ziyad El Hankouri
- grid.28046.380000 0001 2182 2255Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON Canada ,grid.28046.380000 0001 2182 2255Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON Canada
| | - Alexia Kirby
- grid.28046.380000 0001 2182 2255Department of Biology, University of Ottawa, Ottawa, ON Canada
| | - Nigel C. Bennett
- grid.49697.350000 0001 2107 2298Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Barry van Jaarsveld
- grid.49697.350000 0001 2107 2298Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Daniel W. Hart
- grid.49697.350000 0001 2107 2298Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Glenn J. Tattersall
- grid.411793.90000 0004 1936 9318Department of Biological Sciences, Brock University, St. Catharines, ON Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada. .,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada.
| | - Matthew E. Pamenter
- grid.28046.380000 0001 2182 2255Department of Biology, University of Ottawa, Ottawa, ON Canada ,grid.28046.380000 0001 2182 2255University of Ottawa Brain and Mind Research Institute, Ottawa, ON Canada
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18
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Emkuzheva MM, Tembotova FA, Bersekova ZА, Bottaeva ZK, Chapaev АK. Seasonal Dynamics of Erythropoiesis in a Pygmy Wood Mouse (Apodemus uralensis) of the Central Caucasus Mountains. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021050045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Devereaux MEM, Campbell KL, Munro D, Blier PU, Pamenter ME. Burrowing star-nosed moles (Condylura cristata) are not hypoxia tolerant. J Exp Biol 2021; 224:272220. [PMID: 34533564 DOI: 10.1242/jeb.242972] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/07/2021] [Indexed: 11/20/2022]
Abstract
Star-nosed moles (Condylura cristata) have an impressive diving performance and burrowing lifestyle, yet no ventilatory data are available for this or any other talpid mole species. We predicted that, like many other semi-aquatic and fossorial small mammals, star-nosed moles would exhibit: (i) a blunted (i.e. delayed or reduced) hypoxic ventilatory response, (ii) a reduced metabolic rate and (iii) a lowered body temperature (Tb) in hypoxia. We thus non-invasively measured these variables from wild-caught star-nosed moles exposed to normoxia (21% O2) or acute graded hypoxia (21-6% O2). Surprisingly, star-nosed moles did not exhibit a blunted HVR or decreased Tb in hypoxia, and only manifested a significant, albeit small (<8%), depression of metabolic rate at 6% O2 relative to normoxic controls. Unlike small rodents inhabiting similar niches, star-nosed moles are thus intolerant to hypoxia, which may reflect an evolutionary trade-off favouring the extreme sensory biology of this unusual insectivore.
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Affiliation(s)
| | - Kevin L Campbell
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 2N2
| | - Daniel Munro
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - Pierre U Blier
- Départment de Biologie, L'Université du Québec à Rimouski, Rimouski, QC, Canada, G5L 3A1
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5.,University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada, K1H 8M5
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20
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Cheng H, Munro D, Huynh K, Pamenter ME. Naked mole-rat skeletal muscle mitochondria exhibit minimal functional plasticity in acute or chronic hypoxia. Comp Biochem Physiol B Biochem Mol Biol 2021; 255:110596. [PMID: 33757832 DOI: 10.1016/j.cbpb.2021.110596] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 01/10/2023]
Abstract
Oxidative phosphorylation is compromised in hypoxia, but many organisms live and exercise in low oxygen environments. Hypoxia-driven adaptations at the mitochondrial level are common and may enhance energetic efficiency or minimize deleterious reactive oxygen species (ROS) generation. Mitochondria from various hypoxia-tolerant animals exhibit robust functional changes following in vivo hypoxia and we hypothesized that similar plasticity would occur in naked mole-rat skeletal muscle. To test this, we exposed adult subordinate naked mole-rats to normoxia (21% O2) or acute (4 h, 7% O2) or chronic hypoxia (4-6 weeks, 11% O2) and then isolated skeletal muscle mitochondria. Using high-resolution respirometry and a fluorescent indicator of ROS production, we then probed for changes in: i) lipid- (palmitoylcarnitine-malate), ii) carbohydrate- (pyruvate-malate), and iii) succinate-fueled metabolism, and also iv) complex IV electron transfer capacity, and v) H2O2 production. Compared to normoxic values, a) lipid-fueled uncoupled respiration was reduced ~15% during acute and chronic hypoxia, b) complex I-II capacity and the rate of ROS efflux were both unaffected, and c) complex II and IV uncoupled respiration were supressed ~16% following acute hypoxia. Notably, complex II-linked H2O2 efflux was 33% lower after acute hypoxia, which may reduce deleterious ROS bursts during reoxygenation. These mild changes in lipid- and carbohydrate-fueled respiratory capacity may reflect the need for this animal to exercise regularly in highly variable and intermittently hypoxic environments in which more robust plasticity may be energetically expensive.
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Affiliation(s)
- Hang Cheng
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Daniel Munro
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kenny Huynh
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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21
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Pejo M, Tomasco IH. Adaptive evolution of β-globin gene in subterranean in South America octodontid rodents. Gene 2020; 772:145352. [PMID: 33359035 DOI: 10.1016/j.gene.2020.145352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/15/2020] [Accepted: 12/01/2020] [Indexed: 11/17/2022]
Abstract
The convergent evolution of subterranean rodents is an excellent model to study how natural selection operates and the genetic bases of these adaptations, but the study on the different taxa has been very uneven and still insufficient. In the octodontoid caviomorph rodent superfamily there are two independent lineages where they have recently evolved into totally underground lifestyles: the genera Ctenomys (tuco-tucos) and Spalacopus (coruro). The underground habitat is characterized by an hypoxic and hypercapnic atmosphere, thus gas exchange is one of the most important challenges for these animals. The invasion of the underground niche could have modified the selective regimes of proteins involved in the respiration and transport of O2 of these rodents, positively selecting mutations of higher affinity for O2. Here we examine the sequence variation in the beta globin gene in these two lineages, within a robust phylogenetic context. Using different approaches (classical and Bayesian maximum likelihood (PAML/Datamonkey) and alternatives methods (TreeSAAP)) we found at least three sites with evidence of positive selection in underground lineages, especially the basal branch that leads to the Octodontidae family and the branch that leads to the coruro, suggesting some adaptive changes to the underground life. We also found a convergence with another underground rodent, which cannot be identified by the above methods.
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Affiliation(s)
- Mariana Pejo
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Ivanna H Tomasco
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
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22
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Mikuła-Pietrasik J, Pakuła M, Markowska M, Uruski P, Szczepaniak-Chicheł L, Tykarski A, Książek K. Nontraditional systems in aging research: an update. Cell Mol Life Sci 2020; 78:1275-1304. [PMID: 33034696 PMCID: PMC7904725 DOI: 10.1007/s00018-020-03658-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 09/15/2020] [Accepted: 09/28/2020] [Indexed: 12/19/2022]
Abstract
Research on the evolutionary and mechanistic aspects of aging and longevity has a reductionist nature, as the majority of knowledge originates from experiments on a relatively small number of systems and species. Good examples are the studies on the cellular, molecular, and genetic attributes of aging (senescence) that are primarily based on a narrow group of somatic cells, especially fibroblasts. Research on aging and/or longevity at the organismal level is dominated, in turn, by experiments on Drosophila melanogaster, worms (Caenorhabditis elegans), yeast (Saccharomyces cerevisiae), and higher organisms such as mice and humans. Other systems of aging, though numerous, constitute the minority. In this review, we collected and discussed a plethora of up-to-date findings about studies of aging, longevity, and sometimes even immortality in several valuable but less frequently used systems, including bacteria (Caulobacter crescentus, Escherichia coli), invertebrates (Turritopsis dohrnii, Hydra sp., Arctica islandica), fishes (Nothobranchius sp., Greenland shark), reptiles (giant tortoise), mammals (blind mole rats, naked mole rats, bats, elephants, killer whale), and even 3D organoids, to prove that they offer biogerontologists as much as the more conventional tools. At the same time, the diversified knowledge gained owing to research on those species may help to reconsider aging from a broader perspective, which should translate into a better understanding of this tremendously complex and clearly system-specific phenomenon.
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Affiliation(s)
- Justyna Mikuła-Pietrasik
- Department of Pathophysiology of Ageing and Civilization Diseases, Poznań University of Medical Sciences, Długa 1/2 Str., 61-848 Poznań, Poland
| | - Martyna Pakuła
- Department of Hypertensiology, Poznań University of Medical Sciences, Długa 1/2 Str., 61-848 Poznań, Poland
| | - Małgorzata Markowska
- Department of Hypertensiology, Poznań University of Medical Sciences, Długa 1/2 Str., 61-848 Poznań, Poland
| | - Paweł Uruski
- Department of Hypertensiology, Poznań University of Medical Sciences, Długa 1/2 Str., 61-848 Poznań, Poland
| | | | - Andrzej Tykarski
- Department of Hypertensiology, Poznań University of Medical Sciences, Długa 1/2 Str., 61-848 Poznań, Poland
| | - Krzysztof Książek
- Department of Pathophysiology of Ageing and Civilization Diseases, Poznań University of Medical Sciences, Długa 1/2 Str., 61-848 Poznań, Poland
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Rossi GS, Cochrane PV, Wright PA. Fluctuating environments during early development can limit adult phenotypic flexibility: insights from an amphibious fish. J Exp Biol 2020; 223:jeb228304. [PMID: 32616545 DOI: 10.1242/jeb.228304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/29/2020] [Indexed: 12/11/2022]
Abstract
The interaction between developmental plasticity and the capacity for reversible acclimation (phenotypic flexibility) is poorly understood, particularly in organisms exposed to fluctuating environments. We used an amphibious killifish (Kryptolebias marmoratus) to test the hypotheses that organisms reared in fluctuating environments (i) will make no developmental changes to suit any one environment because fixing traits to suit one environment could be maladaptive for another, and (ii) will be highly phenotypically flexible as adults because their early life experiences predict high environmental variability in the future. We reared fish under constant (water) or fluctuating (water-air) environments until adulthood and assessed a suite of traits along the oxygen cascade (e.g. neuroepithelial cell density and size, cutaneous capillarity, gill morphology, ventricle size, red muscle morphometrics, terrestrial locomotor performance). To evaluate the capacity for phenotypic flexibility, a subset of adult fish from each rearing condition was then air-exposed for 14 days before the same traits were measured. In support of the developmental plasticity hypothesis, traits involved with O2 sensing and uptake were largely unaffected by water-air fluctuations during early life, but we found marked developmental changes in traits related to O2 transport, utilization and locomotor performance. In contrast, we found no evidence supporting the phenotypic flexibility hypothesis. Adult fish from both rearing conditions exhibited the same degree of phenotypic flexibility in various O2 sensing- and uptake-related traits. In other cases, water-air fluctuations attenuated adult phenotypic flexibility despite the fact that phenotypic flexibility is hypothesized to be favoured when environments fluctuate. Overall, we conclude that exposure to environmental fluctuations during development in K. marmoratus can dramatically alter the constitutive adult phenotype, as well as diminish the scope for phenotypic flexibility in later life.
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Affiliation(s)
- Giulia S Rossi
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Paige V Cochrane
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
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Pamenter ME, Hall JE, Tanabe Y, Simonson TS. Cross-Species Insights Into Genomic Adaptations to Hypoxia. Front Genet 2020; 11:743. [PMID: 32849780 PMCID: PMC7387696 DOI: 10.3389/fgene.2020.00743] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
Over millions of years, vertebrate species populated vast environments spanning the globe. Among the most challenging habitats encountered were those with limited availability of oxygen, yet many animal and human populations inhabit and perform life cycle functions and/or daily activities in varying degrees of hypoxia today. Of particular interest are species that inhabit high-altitude niches, which experience chronic hypobaric hypoxia throughout their lives. Physiological and molecular aspects of adaptation to hypoxia have long been the focus of high-altitude populations and, within the past decade, genomic information has become increasingly accessible. These data provide an opportunity to search for common genetic signatures of selection across uniquely informative populations and thereby augment our understanding of the mechanisms underlying adaptations to hypoxia. In this review, we synthesize the available genomic findings across hypoxia-tolerant species to provide a comprehensive view of putatively hypoxia-adaptive genes and pathways. In many cases, adaptive signatures across species converge on the same genetic pathways or on genes themselves [i.e., the hypoxia inducible factor (HIF) pathway). However, specific variants thought to underlie function are distinct between species and populations, and, in most cases, the precise functional role of these genomic differences remains unknown. Efforts to standardize these findings and explore relationships between genotype and phenotype will provide important clues into the evolutionary and mechanistic bases of physiological adaptations to environmental hypoxia.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- Ottawa Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - James E. Hall
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Yuuka Tanabe
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
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25
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Devereaux MEM, Pamenter ME. Fossorial giant Zambian mole-rats have blunted ventilatory responses to environmental hypoxia and hypercapnia. Comp Biochem Physiol A Mol Integr Physiol 2020; 243:110672. [PMID: 32032753 DOI: 10.1016/j.cbpa.2020.110672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/28/2020] [Accepted: 02/02/2020] [Indexed: 10/25/2022]
Abstract
Fossorial giant Zambian mole-rats are believed to live in a hypoxic and hypercapnic subterranean environment but their physiological responses to these challenges are entirely unknown. To investigate this, we exposed awake and freely-behaving animals to i) 6 h of normoxia, ii) acute graded normocapnic hypoxia (21, 18, 15, 12, 8, and 5% O2, 0% CO2, balance N2; 1 h each), or iii) acute graded normoxic hypercapnia (0, 2, 5, 7, 9, and 10% CO2, 21% O2, balance N2; 1 h each), followed by a 1 h normoxic normocapnic recovery period, while non-invasively measuring ventilation, metabolic rate, and body temperature (Tb). We found that these mole-rats had a blunted hypoxic ventilatory response that manifested at 12% inhaled O2, a robust hypoxic metabolic response (up to a 68% decrease, starting at 15% O2), and decreased Tb (at or below 8% O2). Upon reoxygenation, metabolic rate increased 52% above normoxic levels, suggesting the paying off of an O2 debt. Ventilation was less sensitive to environmental hypercapnia than to environmental hypoxia and animals also exhibited a blunted hypercapnic ventilatory response that did not manifest below 9% inhaled CO2. Conversely, metabolism and Tb were not affected by hypercapnia. Taken together, these results indicate that, like most other fossorial rodents, giant Zambian mole-rats have blunted hypoxic and hypercapnic ventilatory responses and employ metabolic suppression to tolerate acute hypoxia. Blunted physiological responses to hypoxia and hypercapnia likely reflect the subterranean lifestyle of this mammal, wherein intermittent but severe hypoxia and/or hypercapnia may be common challenges.
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Affiliation(s)
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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26
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Ivy CM, Sprenger RJ, Bennett NC, Jaarsveld B, Hart DW, Kirby AM, Yaghoubi D, Storey KB, Milsom WK, Pamenter ME. The hypoxia tolerance of eight related African mole-rat species rivals that of naked mole-rats, despite divergent ventilatory and metabolic strategies in severe hypoxia. Acta Physiol (Oxf) 2020; 228:e13436. [PMID: 31885213 DOI: 10.1111/apha.13436] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/11/2019] [Accepted: 12/25/2019] [Indexed: 12/21/2022]
Abstract
AIMS Burrowing mammals tend to be more hypoxia tolerant than non-burrowing mammals and rely less on increases in ventilation and more on decreases in metabolic rate to tolerate hypoxia. Naked mole-rats (Heterocephalus glaber, NMRs), eusocial mammals that live in large colonies, are among the most hypoxia-tolerant mammals, and rely almost solely on decreases in metabolism with little change in ventilation during hypoxia. We hypothesized that the remarkable hypoxia tolerance of NMRs is an evolutionarily conserved trait derived from repeated exposure to severe hypoxia owing to their burrow environment and eusocial colony organization. METHODS We used whole-body plethysmography and indirect calorimetry to measure the hypoxic ventilatory and metabolic responses of eight mole-rat species closely related to the NMR. RESULTS We found that all eight species examined had a strong tolerance to hypoxia, with most species tolerating 3 kPa O2 , Heliophobius emini tolerating 2 kPa O2 and Bathyergus suillus tolerating 5 kPa O2 . All species examined employed a combination of increases in ventilation and decreases in metabolism in hypoxia, a response midway between that of the NMR and that of other fossorial species (larger ventilatory responses, lesser reductions in metabolism). We found that eusociality is not fundamental to the physiological response to hypoxia of NMRs as Fukomys damarensis, another eusocial species, was among this group. CONCLUSIONS Our data suggest that, while the NMR is unique in the pattern of their physiological response to hypoxia, eight closely related mole-rat species share the ability to tolerate hypoxia like the current "hypoxia-tolerant champion," the NMR.
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Affiliation(s)
| | - Ryan J. Sprenger
- Department of Zoology University of British Columbia Vancouver BC Canada
| | - Nigel C. Bennett
- Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Barry Jaarsveld
- Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Daniel W. Hart
- Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | | | | | | | - William K. Milsom
- Department of Zoology University of British Columbia Vancouver BC Canada
| | - Matthew E. Pamenter
- Department of Biology University of Ottawa Ottawa ON Canada
- Ottawa Brain and Mind Research Institute University of Ottawa Ottawa ON Canada
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Sokolova IM, Sokolov EP, Haider F. Mitochondrial Mechanisms Underlying Tolerance to Fluctuating Oxygen Conditions: Lessons from Hypoxia-Tolerant Organisms. Integr Comp Biol 2020; 59:938-952. [PMID: 31120535 DOI: 10.1093/icb/icz047] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Oxygen (O2) is essential for most metazoan life due to its central role in mitochondrial oxidative phosphorylation (OXPHOS), which generates >90% of the cellular adenosine triphosphate. O2 fluctuations are an ultimate mitochondrial stressor resulting in mitochondrial damage, energy deficiency, and cell death. This work provides an overview of the known and putative mechanisms involved in mitochondrial tolerance to fluctuating O2 conditions in hypoxia-tolerant organisms including aquatic and terrestrial vertebrates and invertebrates. Mechanisms of regulation of the mitochondrial OXPHOS and electron transport system (ETS) (including alternative oxidases), sulphide tolerance, regulation of redox status and mitochondrial quality control, and the potential role of hypoxia-inducible factor (HIF) in mitochondrial tolerance to hypoxia are discussed. Mitochondrial phenotypes of distantly related animal species reveal common features including conservation and/or anticipatory upregulation of ETS capacity, suppression of reactive oxygen species (ROS)-producing electron flux through ubiquinone, reversible suppression of OXPHOS activity, and investment into the mitochondrial quality control mechanisms. Despite the putative importance of oxidative stress in adaptations to hypoxia, establishing the link between hypoxia tolerance and mitochondrial redox mechanisms is complicated by the difficulties of establishing the species-specific concentration thresholds above which the damaging effects of ROS outweigh their potentially adaptive signaling function. The key gaps in our knowledge about the potential mechanisms of mitochondrial tolerance to hypoxia include regulation of mitochondrial biogenesis and fusion/fission dynamics, and HIF-dependent metabolic regulation that require further investigation in hypoxia-tolerant species. Future physiological, molecular and genetic studies of mitochondrial responses to hypoxia, and reoxygenation in phylogenetically diverse hypoxia-tolerant species could reveal novel solutions to the ubiquitous and metabolically severe problem of O2 deficiency and would have important implications for understanding the evolution of hypoxia tolerance and the potential mitigation of pathological states caused by O2 fluctuations.
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Affiliation(s)
- Inna M Sokolova
- Department of Marine Biology, University of Rostock, Rostock, Germany.,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Eugene P Sokolov
- Leibniz Institute for Baltic Sea Research, Leibniz ScienceCampus Phosphorus Research Rostock, Warnemünde, Germany
| | - Fouzia Haider
- Department of Marine Biology, University of Rostock, Rostock, Germany
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28
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Vandewint AL, Zhu-Pawlowsky AJ, Kirby A, Tattersall GJ, Pamenter ME. Evaporative cooling and vasodilation mediate thermoregulation in naked mole-rats during normoxia but not hypoxia. J Therm Biol 2019; 84:228-235. [DOI: 10.1016/j.jtherbio.2019.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 12/20/2022]
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29
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Dzal YA, Seow A, Borecky LG, Chung D, Gill SKG, Milsom WK, Pamenter ME. Glutamatergic Receptors Modulate Normoxic but Not Hypoxic Ventilation and Metabolism in Naked Mole Rats. Front Physiol 2019; 10:106. [PMID: 30833905 PMCID: PMC6387965 DOI: 10.3389/fphys.2019.00106] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/28/2019] [Indexed: 11/28/2022] Open
Abstract
Naked mole rats (Heterocephalus glaber) are among the most hypoxia-tolerant mammals, but their physiological responses to acute and chronic sustained hypoxia (CSH), and the molecular underpinnings of these responses, are poorly understood. In the present study we evaluated the acute hypoxic ventilatory response and the occurrence of ventilatory acclimatization to hypoxia following CSH exposure (8–10 days in 8% O2) of naked mole rats. We also investigated the role of excitatory glutamatergic signaling in the control of ventilation and metabolism in these conditions. Animals acclimated to normoxia (control) or CSH and then exposed to acute hypoxia (7% O2 for 1 h) exhibited elevated tidal volume (VT), but decreased breathing frequency (fR). As a result, total ventilation (V.E) remained unchanged. Conversely, VT was lower in CSH animals relative to controls, suggesting that there is ventilatory plasticity following acclimatization to chronic hypoxia. Both control and CSH-acclimated naked mole rats exhibited similar 60–65% decreases in O2 consumption rate during acute hypoxia, and as a result their air convection requirement (ACR) increased ∼2.4 to 3-fold. Glutamatergic receptor inhibition decreased fR, V.E, and the rate of O2 consumption in normoxia but did not alter these ventilatory or metabolic responses to acute hypoxia in either the control or CSH groups. Taken together, these findings indicate that ventilatory acclimatization to hypoxia is atypical in naked mole rats, and glutamatergic signaling is not involved in their hypoxic ventilatory or metabolic responses to acute or chronic hypoxia.
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Affiliation(s)
- Yvonne A Dzal
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Department of Biology, Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, MB, Canada
| | - Allison Seow
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Lisa G Borecky
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Danielle Chung
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Sharn K G Gill
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Matthew E Pamenter
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
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30
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Zhang SY, Pamenter ME. Ventilatory, metabolic, and thermoregulatory responses of Damaraland mole rats to acute and chronic hypoxia. J Comp Physiol B 2019; 189:319-334. [DOI: 10.1007/s00360-019-01206-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 01/13/2019] [Accepted: 01/27/2019] [Indexed: 01/22/2023]
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31
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Guadarrama SS, Domínguez-Vega H, Díaz-Albiter HM, Quijano A, Bastiaans E, Carrillo-Castilla P, Manjarrez J, Gómez-Ortíz Y, Fajardo V. Hypoxia by Altitude and Welfare of Captive Beaded Lizards ( Heloderma Horridum) in Mexico: Hematological Approaches. J APPL ANIM WELF SCI 2019; 23:74-82. [PMID: 30626215 DOI: 10.1080/10888705.2018.1562350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Heloderma horridum is one of the few known venomous lizards in the world. Their populations are in decline due to habitat destruction and capture for the pet trade. In México, many zoos have decided to take care of this species, most of them at altitudes greater than the natural altitudinal distribution. However, we know little about the capacity of the reptiles to face high-altitude environments. The objective of this study was to compare hematological traits of H. horridum in captivity in high and low altitude environments. Our findings show that H. horridum does not respond to hypoxic environments, at least in blood traits, and that the organisms appear to be in homeostasis. Although we cannot know if individual H. horridum housed in high-altitude environments are completely comfortable, it appears hypoxia can be avoid without modifications of blood parameters. We suggest that future work should address changes in metabolic rates and in behavioral aspects to understand how to maintain the health and comfort of the reptiles native to low altitude when they are housed in high-altitude environments.
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Affiliation(s)
- Sonia S Guadarrama
- Posgrado en Ciencias Agropecuarias y Recursos Naturales, Universidad Autónoma del Estado de México, Toluca, México
| | - Hublester Domínguez-Vega
- División de Desarrollo Sustentable, Universidad Intercultural del Estado de México, San Felipe del Progreso, Mexico
| | - Hector M Díaz-Albiter
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,Unidad Villahermosa, El Colegio de la Frontera Sur (ECOSUR), Tabasco, Mexico
| | - Alejandro Quijano
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, Toluca, México
| | - Elizabeth Bastiaans
- Biology Department, State University of New York College at Oneonta, Oneonta, NY, USA
| | - Porfirio Carrillo-Castilla
- Laboratorio de Neurobiología del Desarrollo, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, México
| | - Javier Manjarrez
- Facultad de Ciencias, Universidad Autónoma del Estado de México, Toluca, México
| | - Yuriana Gómez-Ortíz
- División de Desarrollo Sustentable, Universidad Intercultural del Estado de México, San Felipe del Progreso, Mexico
| | - Victor Fajardo
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, Toluca, México
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32
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Houlahan CR, Kirby AM, Dzal YA, Fairman GD, Pamenter ME. Divergent behavioural responses to acute hypoxia between individuals and groups of naked mole rats. Comp Biochem Physiol B Biochem Mol Biol 2018; 224:38-44. [DOI: 10.1016/j.cbpb.2018.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/28/2017] [Accepted: 01/10/2018] [Indexed: 11/30/2022]
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33
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The hypoxia-tolerant vertebrate brain: Arresting synaptic activity. Comp Biochem Physiol B Biochem Mol Biol 2018; 224:61-70. [DOI: 10.1016/j.cbpb.2017.11.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/23/2017] [Accepted: 11/30/2017] [Indexed: 01/16/2023]
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34
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Behavioural responses to environmental hypercapnia in two eusocial species of African mole rats. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:811-819. [DOI: 10.1007/s00359-018-1283-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/19/2018] [Accepted: 08/24/2018] [Indexed: 01/10/2023]
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35
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Ilacqua AN, Kirby AM, Pamenter ME. Behavioural responses of naked mole rats to acute hypoxia and anoxia. Biol Lett 2018; 13:rsbl.2017.0545. [PMID: 29263131 DOI: 10.1098/rsbl.2017.0545] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/23/2017] [Indexed: 12/21/2022] Open
Abstract
Naked mole rats (NMRs) are among the most hypoxia-tolerant mammals. Other species respond to hypoxia by either escaping the hypoxic environment or drastically decreasing behavioural activity and body temperature (Tb) to conserve energy. However, NMRs rarely leave their underground burrows, which are putatively hypoxic and thermally stable near the NMRs' preferred Tb Therefore, we asked whether NMRs are able to employ behavioural and thermoregulatory strategies in response to hypoxia despite their need to remain active and the minimal thermal scope in their burrows. We exposed NMRs to progressively deeper levels of hypoxia (from 21 to 0% O2) while measuring their behaviour and Tb Behavioural activity decreased 40-60% in hypoxia and Tb decreased slightly in moderate hypoxia (5-9%) and then further with deeper hypoxia (3% O2). However, even at 3% O2 NMRs remained somewhat active and warm, and continued to explore their environment. Remarkably, NMRs were active for greater than 90 s in acute anoxia and Tb and metabolic rate decreased rapidly. We conclude that NMRs are adapted to remain awake and functional even at the extremes of their hypoxia-tolerance. This adaptation likely reflects variable and challenging levels of environmental hypoxia in the natural habitat of this species.
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Affiliation(s)
- Aaron N Ilacqua
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, Ontario, Canada K1N 6N5
| | - Alexia M Kirby
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, Ontario, Canada K1N 6N5
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, Ontario, Canada K1N 6N5 .,Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada
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36
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Gattuso A, Garofalo F, Cerra MC, Imbrogno S. Hypoxia Tolerance in Teleosts: Implications of Cardiac Nitrosative Signals. Front Physiol 2018; 9:366. [PMID: 29706897 PMCID: PMC5906588 DOI: 10.3389/fphys.2018.00366] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/26/2018] [Indexed: 12/18/2022] Open
Abstract
Changes in environmental oxygen (O2) are naturally occurring phenomena which ectotherms have to face on. Many species exhibit a striking capacity to survive and remain active for long periods under hypoxia, even tolerating anoxia. Some fundamental adaptations contribute to this capacity: metabolic suppression, tolerance of pH and ionic unbalance, avoidance and/or repair of free-radical-induced cell injury during reoxygenation. A remarkable feature of these species is their ability to preserve a normal cardiovascular performance during hypoxia/anoxia to match peripheral (tissue pO2) requirements. In this review, we will refer to paradigms of hypoxia- and anoxia-tolerant teleost fish to illustrate cardiac physiological strategies that, by involving nitric oxide and its metabolites, play a critical role in the adaptive responses to O2 limitation. The information here reported may contribute to clarify the molecular and cellular mechanisms underlying heart vulnerability vs. resistance in relation to O2 availability.
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Affiliation(s)
- Alfonsina Gattuso
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende, Italy
| | - Filippo Garofalo
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende, Italy
| | - Maria C Cerra
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende, Italy
| | - Sandra Imbrogno
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende, Italy
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37
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Kirby AM, Fairman GD, Pamenter ME. Atypical behavioural, metabolic and thermoregulatory responses to hypoxia in the naked mole rat (Heterocephalus glaber
). J Zool (1987) 2018. [DOI: 10.1111/jzo.12542] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Alexia M Kirby
- Department of Biology; University of Ottawa; Ottawa ON Canada
| | | | - Matthew E Pamenter
- Department of Biology; University of Ottawa; Ottawa ON Canada
- Brain and Mind Research Institute; University of Ottawa; Ottawa ON Canada
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38
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York JM, Scadeng M, McCracken KG, Milsom WK. Respiratory mechanics and morphology of Tibetan and Andean high-altitude geese with divergent life histories. ACTA ACUST UNITED AC 2018; 221:jeb.170738. [PMID: 29180602 DOI: 10.1242/jeb.170738] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/21/2017] [Indexed: 12/31/2022]
Abstract
High-altitude bar-headed geese (Anser indicus) and Andean geese (Chloephaga melanoptera) have been shown to preferentially increase tidal volume over breathing frequency when increasing ventilation during exposure to hypoxia. Increasing tidal volume is a more effective breathing strategy but is also thought to be more mechanically and metabolically expensive. We asked whether there might be differences in the mechanics or morphology of the respiratory systems of high-altitude transient bar-headed geese and high-altitude resident Andean geese that could minimize the cost of breathing more deeply. We compared these two species with a low-altitude migratory species, the barnacle goose (Branta leucopsis). We ventilated anesthetized birds to measure mechanical properties of the respiratory system and used CT scans to quantify respiratory morphology. We found that the respiratory system of Andean geese was disproportionately larger than that of the other two species, allowing use of a deeper breathing strategy for the same energetic cost. The relative size of the respiratory system, especially the caudal air sacs, of bar-headed geese was also larger than that of barnacle geese. However, when normalized to respiratory system size, the mechanical cost of breathing did not differ significantly among these three species, indicating that deeper breathing is enabled by morphological but not mechanical differences between species. The metabolic cost of breathing was estimated to be <1% of basal metabolic rate at rest in normoxia. Because of differences in the magnitude of the ventilatory response, the cost of breathing was estimated to increase 7- to 10-fold in bar-headed and barnacle geese in severe hypoxia, but less than 1-fold in Andean geese exposed to the same low atmospheric PO2.
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Affiliation(s)
- Julia M York
- University of British Columbia, Department of Zoology, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Miriam Scadeng
- University of California San Diego, Department of Radiology, Center for Functional MRI, 9500 Gilman Drive 0677, La Jolla, CA, USA 92093
| | - Kevin G McCracken
- University of Miami, Department of Biology, Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, and Human Genetics and Genomics - Miller School of Medicine, Coral Gables, FL, 33146, USA
| | - William K Milsom
- University of British Columbia, Department of Zoology, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
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39
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Pamenter ME, Dzal YA, Thompson WA, Milsom WK. Do naked mole rats accumulate a metabolic acidosis or an oxygen debt in severe hypoxia? J Exp Biol 2018; 222:jeb.191197. [DOI: 10.1242/jeb.191197] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/18/2018] [Indexed: 01/02/2023]
Abstract
In severe hypoxia, most vertebrates increase anaerobic energy production, which results in the development of a metabolic acidosis and an O2 debt that must be repaid during reoxygenation. Naked mole rats (NMRs) are among the most hypoxia-tolerant mammals, capable of drastically reducing their metabolic rate in acute hypoxia; while staying active and alert. We hypothesized that a key component of remaining active is an increased reliance on anaerobic metabolism during severe hypoxia. To test this hypothesis, we exposed NMRs to progressive reductions in inspired O2 (9 to 3% O2) followed by reoxygenation (21% O2) and measured breathing frequency, heart rate, behavioural activity, body temperature, metabolic rate, and also metabolic substrates and pH in blood and tissues. We found that NMRs exhibit robust metabolic rate depression in acute hypoxia, accompanied by declines in all physiological and behavioural variables examined. However, blood and tissue pH were unchanged and tissue [ATP] and [phosphocreatine] were maintained. Naked mole rats increased their reliance on carbohydrates in hypoxia, and glucose was mobilized from the liver to the blood. Upon reoxygenation NMRs entered into a coma-like state for∼15-20 mins during which metabolic rate was negligible and body temperature remained suppressed. However, an imbalance in the rates at which V̇O2 and V̇CO2 returned to normoxic levels during reoxygenation hint at the possibility that NMRs do utilize anaerobic metabolism during hypoxia but have a tissue and/or blood buffering capacity that mask typical markers of metabolic acidosis, and prioritize the synthesis of glucose from lactate during recovery.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Yvonne A. Dzal
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
- Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, MB, Canada
| | - William A. Thompson
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
- Department of Biology, University of Calgary, Calgary, AB, Canada
| | - William K. Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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40
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González-Morales JC, Beamonte-Barrientos R, Bastiaans E, Guevara-Fiore P, Quintana E, Fajardo V. A Mountain or a Plateau? Hematological Traits Vary Nonlinearly with Altitude in a Highland Lizard. Physiol Biochem Zool 2017; 90:638-645. [PMID: 28991507 DOI: 10.1086/694833] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
High-altitude organisms exhibit hematological adaptations to augment blood transport of oxygen. One common mechanism is through increased values of blood traits such as erythrocyte count, hematocrit, and hemoglobin concentration. However, a positive relationship between altitude and blood traits is not observed in all high-altitude systems. To understand how organisms adapt to high altitudes, it is important to document physiological patterns related to hypoxia gradients from a greater variety of species. Here, we present an extensive hematological description for three populations of Sceloporus grammicus living at 2,500, 3,400, and 4,300 m. We did not find a linear increase with altitude for any of the blood traits we measured. Instead, we found nonlinear relationships between altitude and the blood traits erythrocyte number, erythrocyte size, hematocrit, and hemoglobin concentration. Erythrocyte number and hematocrit leveled off as altitude increased, whereas hemoglobin concentration and erythrocyte size were highest at intermediate altitude. Additionally, lizards from our three study populations are similar in blood pH, serum electrolytes, glucose, and lactate. Given that the highest-altitude population did not show the highest levels of the variables we measured, we suggest these lizards may be using different adaptations to cope with hypoxia than lizards at low or intermediate altitudes. We discuss future directions that research could take to investigate such potential adaptations.
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41
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O'Mara MT, Wikelski M, Voigt CC, Ter Maat A, Pollock HS, Burness G, Desantis LM, Dechmann DK. Cyclic bouts of extreme bradycardia counteract the high metabolism of frugivorous bats. eLife 2017; 6. [PMID: 28923167 PMCID: PMC5605195 DOI: 10.7554/elife.26686] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/13/2017] [Indexed: 12/04/2022] Open
Abstract
Active flight requires the ability to efficiently fuel bursts of costly locomotion while maximizing energy conservation during non-flying times. We took a multi-faceted approach to estimate how fruit-eating bats (Uroderma bilobatum) manage a high-energy lifestyle fueled primarily by fig juice. Miniaturized heart rate telemetry shows that they use a novel, cyclic, bradycardic state that reduces daily energetic expenditure by 10% and counteracts heart rates as high as 900 bpm during flight. Uroderma bilobatum support flight with some of the fastest metabolic incorporation rates and dynamic circulating cortisol in vertebrates. These bats will exchange fat reserves within 24 hr, meaning that they must survive on the food of the day and are at daily risk of starvation. Energetic flexibly in U. bilobatum highlights the fundamental role of ecological pressures on integrative energetic networks and the still poorly understood energetic strategies of animals in the tropics. To survive, all animals have to balance how much energy they take in and how much they use. They must find enough food to fuel the chemical processes that keep them alive – known as their metabolism – and store leftover fuel to use when food is not available. Bats, for example, have a fast metabolism and powerful flight muscles, which require a lot of energy. Some bat species, such as the tent-making bats, survive on fruit juice, and their food sources are often far apart and difficult to find. These bats are likely to starve if they go without food for more than 24 hours, and therefore need to conserve energy while they are resting. To deal with potential food shortages, bats and other animals can enter a low-energy resting state called torpor. In this state, animals lower their body temperature and slow down their heart rate and metabolism so that they need less energy to stay alive. However, many animals that live in tropical regions, including tent-making bats, cannot enter a state of torpor, as it is too hot to sufficiently lower their body temperature. Until now, scientists did not fully understand how these bats control how much energy they use. Now, O’Mara et al. studied tent-making bats in the wild by attaching small heart rate transmitters to four wild bats, and measured their heartbeats over several days. Since each heartbeat delivers oxygen and fuel to the rest of the body, measuring the bats’ heart rate indicates how much energy they are using. The experiments revealed for the first time that tent-making bats periodically lower their heart rates while resting (to around 200 beats per minute). This reduces the amount of energy they use each day by up to 10%, and helps counteract heart rates that can reach 900 beats per minute when the bats are flying. Overall, these findings show that animals have evolved in various ways to control their use of energy. Future research should use similar technology to continue uncovering how wild animals have adapted to survive in different conditions. This knowledge will help us to understand how life has become so diverse in the tropics and the strategies that animals may use as climates change.
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Affiliation(s)
- M Teague O'Mara
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Smithsonian Tropical Research Institute, Panama City, Panama.,Zukunftskolleg, University of Konstanz, Konstanz, Germany
| | - Martin Wikelski
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Andries Ter Maat
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Starnberg, Germany
| | - Henry S Pollock
- Program in Ecology, Evolution and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Gary Burness
- Department of Biology, Trent University, Peterborough, Canada
| | - Lanna M Desantis
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Canada
| | - Dina Kn Dechmann
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Smithsonian Tropical Research Institute, Panama City, Panama
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42
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Haverinen J, Abramochkin DV, Kamkin A, Vornanen M. Maximum heart rate in brown trout (Salmo trutta fario) is not limited by firing rate of pacemaker cells. Am J Physiol Regul Integr Comp Physiol 2017; 312:R165-R171. [DOI: 10.1152/ajpregu.00403.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/23/2016] [Accepted: 11/23/2016] [Indexed: 01/17/2023]
Abstract
Temperature-induced changes in cardiac output (Q̇) in fish are largely dependent on thermal modulation of heart rate ( fH), and at high temperatures Q̇ collapses due to heat-dependent depression of fH. This study tests the hypothesis that firing rate of sinoatrial pacemaker cells sets the upper thermal limit of fH in vivo. To this end, temperature dependence of action potential (AP) frequency of enzymatically isolated pacemaker cells (pacemaker rate, fPM), spontaneous beating rate of isolated sinoatrial preparations ( fSA), and in vivo fH of the cold-acclimated (4°C) brown trout ( Salmo trutta fario) were compared under acute thermal challenges. With rising temperature, fPM steadily increased because of the acceleration of diastolic depolarization and shortening of AP duration up to the break point temperature (TBP) of 24.0 ± 0.37°C, at which point the electrical activity abruptly ceased. The maximum fPM at TBP was much higher [193 ± 21.0 beats per minute (bpm)] than the peak fSA (94.3 ± 6.0 bpm at 24.1°C) or peak fH (76.7 ± 2.4 at 15.7 ± 0.82°C) ( P < 0.05). These findings strongly suggest that the frequency generator of the sinoatrial pacemaker cells does not limit fH at high temperatures in the brown trout in vivo.
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Affiliation(s)
- Jaakko Haverinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| | - Denis V. Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, Moscow, Russia; and
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova, Moscow, Russia
| | - Andre Kamkin
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova, Moscow, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
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Chung D, Dzal YA, Seow A, Milsom WK, Pamenter ME. Naked mole rats exhibit metabolic but not ventilatory plasticity following chronic sustained hypoxia. Proc Biol Sci 2016; 283:20160216. [PMID: 27009224 DOI: 10.1098/rspb.2016.0216] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/25/2016] [Indexed: 02/03/2023] Open
Abstract
Naked mole rats are among the most hypoxia-tolerant mammals identified and live in chronic hypoxia throughout their lives. The physiological mechanisms underlying this tolerance, however, are poorly understood. Most vertebrates hyperventilate in acute hypoxia and exhibit an enhanced hyperventilation following acclimatization to chronic sustained hypoxia (CSH). Conversely, naked mole rats do not hyperventilate in acute hypoxia and their response to CSH has not been examined. In this study, we explored mechanisms of plasticity in the control of the hypoxic ventilatory response (HVR) and hypoxic metabolic response (HMR) of freely behaving naked mole rats following 8-10 days of chronic sustained normoxia (CSN) or CSH. Specifically, we investigated the role of the major inhibitory neurotransmitter γ-amino butyric acid (GABA) in mediating these responses. Our study yielded three important findings. First, naked mole rats did not exhibit ventilatory plasticity following CSH, which is unique among adult animals studied to date. Second, GABA receptor (GABAR) antagonism altered breathing patterns in CSN and CSH animals and modulated the acute HVR in CSN animals. Third, naked mole rats exhibited GABAR-dependent metabolic plasticity following long-term hypoxia, such that the basal metabolic rate was approximately 25% higher in normoxic CSH animals than CSN animals, and GABAR antagonists modulated this increase.
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Affiliation(s)
- Danielle Chung
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yvonne A Dzal
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Allison Seow
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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Pamenter ME, Powell FL. Time Domains of the Hypoxic Ventilatory Response and Their Molecular Basis. Compr Physiol 2016; 6:1345-85. [PMID: 27347896 DOI: 10.1002/cphy.c150026] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ventilatory responses to hypoxia vary widely depending on the pattern and length of hypoxic exposure. Acute, prolonged, or intermittent hypoxic episodes can increase or decrease breathing for seconds to years, both during the hypoxic stimulus, and also after its removal. These myriad effects are the result of a complicated web of molecular interactions that underlie plasticity in the respiratory control reflex circuits and ultimately control the physiology of breathing in hypoxia. Since the time domains of the physiological hypoxic ventilatory response (HVR) were identified, considerable research effort has gone toward elucidating the underlying molecular mechanisms that mediate these varied responses. This research has begun to describe complicated and plastic interactions in the relay circuits between the peripheral chemoreceptors and the ventilatory control circuits within the central nervous system. Intriguingly, many of these molecular pathways seem to share key components between the different time domains, suggesting that varied physiological HVRs are the result of specific modifications to overlapping pathways. This review highlights what has been discovered regarding the cell and molecular level control of the time domains of the HVR, and highlights key areas where further research is required. Understanding the molecular control of ventilation in hypoxia has important implications for basic physiology and is emerging as an important component of several clinical fields. © 2016 American Physiological Society. Compr Physiol 6:1345-1385, 2016.
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Affiliation(s)
| | - Frank L Powell
- Physiology Division, Department of Medicine, University of California San Diego, La Jolla, California, USA
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Mesenchymal Stem/Stromal Cells from Discarded Neonatal Sternal Tissue: In Vitro Characterization and Angiogenic Properties. Stem Cells Int 2015; 2016:5098747. [PMID: 26770206 PMCID: PMC4684890 DOI: 10.1155/2016/5098747] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 07/22/2015] [Indexed: 12/13/2022] Open
Abstract
Autologous and nonautologous bone marrow mesenchymal stem/stromal cells (MSCs) are being evaluated as proangiogenic agents for ischemic and vascular disease in adults but not in children. A significant number of newborns and infants with critical congenital heart disease who undergo cardiac surgery already have or are at risk of developing conditions related to inadequate tissue perfusion. During neonatal cardiac surgery, a small amount of sternal tissue is usually discarded. Here we demonstrate that MSCs can be isolated from human neonatal sternal tissue using a nonenzymatic explant culture method. Neonatal sternal bone MSCs (sbMSCs) were clonogenic, had a surface marker expression profile that was characteristic of bone marrow MSCs, were multipotent, and expressed pluripotency-related genes at low levels. Neonatal sbMSCs also demonstrated in vitro proangiogenic properties. Sternal bone MSCs cooperated with human umbilical vein endothelial cells (HUVECs) to form 3D networks and tubes in vitro. Conditioned media from sbMSCs cultured in hypoxia also promoted HUVEC survival and migration. Given the neonatal source, ease of isolation, and proangiogenic properties, sbMSCs may have relevance to therapeutic applications.
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Funk GD, Kinkead R. Fuelling the Fire of Life: A tribute to Professor W.K. Milsom. Comp Biochem Physiol A Mol Integr Physiol 2015; 186:1-3. [DOI: 10.1016/j.cbpa.2015.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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