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Allen KN, Torres-Velarde JM, Vazquez JM, Moreno-Santillán DD, Sudmant PH, Vázquez-Medina JP. Hypoxia exposure blunts angiogenic signaling and upregulates the antioxidant system in endothelial cells derived from elephant seals. BMC Biol 2024; 22:91. [PMID: 38654271 PMCID: PMC11040891 DOI: 10.1186/s12915-024-01892-3] [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: 09/29/2023] [Accepted: 04/17/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Elephant seals exhibit extreme hypoxemic tolerance derived from repetitive hypoxia/reoxygenation episodes they experience during diving bouts. Real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture model from elephant seals and used RNA-seq, functional assays, and confocal microscopy to assess the molecular response to prolonged hypoxia. RESULTS Seal and human endothelial cells exposed to 1% O2 for up to 6 h respond differently to acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling. Rapid upregulation of genes involved in glutathione (GSH) metabolism supports the maintenance of GSH pools, and intracellular succinate increases in seal but not human cells. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurs in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting that seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure. CONCLUSIONS We found that the glutathione antioxidant system is upregulated in seal endothelial cells during hypoxia, while this system remains static in comparable human cells. Furthermore, we found that in contrast to human cells, hypoxia exposure rapidly activates HIF-1 in seal cells, but this response is decoupled from the canonical angiogenesis pathway. These results highlight the unique mechanisms that confer extraordinary tolerance to limited oxygen availability in a champion diving mammal.
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Affiliation(s)
- Kaitlin N Allen
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | | | - Juan Manuel Vazquez
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | | | - Peter H Sudmant
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
- Center for Computational Biology, University of California Berkeley, Berkeley, CA, 94720, USA
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Graïc JM, Mazzariol S, Casalone C, Petrella A, Gili C, Gerussi T, Orekhova K, Centelleghe C, Cozzi B. Report on the brain of the monk seal (Monachus monachus, Hermann, 1779). Anat Histol Embryol 2024; 53:e12986. [PMID: 37843436 DOI: 10.1111/ahe.12986] [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: 02/22/2023] [Revised: 09/28/2023] [Accepted: 10/04/2023] [Indexed: 10/17/2023]
Abstract
The Mediterranean monk seal (Monachus monachus, Hermann, 1779) is an endangered species of pinniped endemic to few areas of the Mediterranean Sea. Extensive hunting and poaching over the last two centuries have rendered it a rare sight, scattered mainly in the Aegean Sea and the western coast of North Africa. In a rare event, a female monk seal calf stranded and died in southern Italy (Brindisi, Puglia). During due necropsy, the brain was extracted and fixed. The present report is the first of a monk seal brain. The features reported are remarkably typical of a true seal brain, with some specific characteristics. The brain cortical circonvolutions, main fissures and the external parts are described, and an EQ was calculated. Overall, this carnivore adapted to aquatic life shares some aspects of its neuroanatomy and physiology with other seemingly distant aquatic mammals.
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Affiliation(s)
- Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, Italy
| | - Sandro Mazzariol
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, Italy
| | - Cristina Casalone
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
| | - Antonio Petrella
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Foggia, Italy
| | | | - Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, Italy
| | - Ksenia Orekhova
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, Italy
| | - Cinzia Centelleghe
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, Italy
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Allen KN, Torres-Velarde JM, Vazquez JM, Moreno-Santillan DD, Sudmant PH, Vázquez-Medina JP. Hypoxia blunts angiogenic signaling and upregulates the antioxidant system in elephant seal endothelial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.01.547248. [PMID: 37461722 PMCID: PMC10350019 DOI: 10.1101/2023.07.01.547248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Elephant seals experience extreme hypoxemia during diving bouts. Similar depletions in oxygen availability characterize pathologies including myocardial infarction and ischemic stroke in humans, but seals manage these repeated episodes without injury. However, the real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture system to assess the molecular response to prolonged hypoxia. Seal and human cells exposed to 1% O 2 for up to 6 h demonstrated differential responses to both acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling at both the transcriptional and cellular level. Rapid upregulation of genes involved in the glutathione (GSH) metabolism pathway supported maintenance of GSH pools and increases in intracellular succinate in seal but not human cells during hypoxia exposure. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurred in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure. In sum, our studies show that in contrast to human cells, seal cells adapt to hypoxia exposure by dampening angiogenic signaling, increasing antioxidant protection, and maintaining mitochondrial morphological integrity and function.
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Noh HJ, Turner-Maier J, Schulberg SA, Fitzgerald ML, Johnson J, Allen KN, Hückstädt LA, Batten AJ, Alfoldi J, Costa DP, Karlsson EK, Zapol WM, Buys ES, Lindblad-Toh K, Hindle AG. The Antarctic Weddell seal genome reveals evidence of selection on cardiovascular phenotype and lipid handling. Commun Biol 2022; 5:140. [PMID: 35177770 PMCID: PMC8854659 DOI: 10.1038/s42003-022-03089-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/31/2022] [Indexed: 12/24/2022] Open
Abstract
AbstractThe Weddell seal (Leptonychotes weddellii) thrives in its extreme Antarctic environment. We generated the Weddell seal genome assembly and a high-quality annotation to investigate genome-wide evolutionary pressures that underlie its phenotype and to study genes implicated in hypoxia tolerance and a lipid-based metabolism. Genome-wide analyses included gene family expansion/contraction, positive selection, and diverged sequence (acceleration) compared to other placental mammals, identifying selection in coding and non-coding sequence in five pathways that may shape cardiovascular phenotype. Lipid metabolism as well as hypoxia genes contained more accelerated regions in the Weddell seal compared to genomic background. Top-significant genes were SUMO2 and EP300; both regulate hypoxia inducible factor signaling. Liver expression of four genes with the strongest acceleration signals differ between Weddell seals and a terrestrial mammal, sheep. We also report a high-density lipoprotein-like particle in Weddell seal serum not present in other mammals, including the shallow-diving harbor seal.
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John JS, Thometz NM, Boerner K, Denum L, Kendall TL, Richter BP, Gaspard JC, Williams TM. Metabolic trade-offs in tropical and subtropical marine mammals: unique maintenance and locomotion costs in West Indian manatees and Hawaiian monk seals. J Exp Biol 2021; 224:271210. [PMID: 34357378 PMCID: PMC8353161 DOI: 10.1242/jeb.237628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 06/09/2021] [Indexed: 11/20/2022]
Abstract
Unlike the majority of marine mammal species, Hawaiian monk seals (Neomonachus schauinslandi) and West Indian manatees (Trichechus manatus latirostris) reside exclusively in tropical or subtropical waters. Although potentially providing an energetic benefit through reduced maintenance and thermal costs, little is known about the cascading effects that may alter energy expenditure during activity, dive responses and overall energy budgets for these warm-water species. To examine this, we used open-flow respirometry to measure the energy expended during resting and swimming in both species. We found that the average resting metabolic rates (RMRs) for both the adult monk seal (753.8±26.1 kJ h-1, mean±s.e.m.) and manatees (887.7±19.5 kJ h-1) were lower than predicted for cold-water marine mammal species of similar body mass. Despite these relatively low RMRs, both total cost per stroke and total cost of transport (COTTOT) during submerged swimming were similar to predictions for comparably sized marine mammals (adult monk seal: cost per stroke=5.0±0.2 J kg-1 stroke-1, COTTOT=1.7±0.1 J kg-1 m-1; manatees: cost per stroke=2.0±0.4 J kg-1 stroke-1, COTTOT=0.87±0.17 J kg-1 m-1). These lower maintenance costs result in less variability in adjustable metabolic costs that occur during submergence for warm-water species. However, these reduced maintenance costs do not appear to confer an advantage in overall energetic costs during activity, potentially limiting the capacity of warm-water species to respond to anthropogenic or environmental threats that require increased energy expenditure.
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Affiliation(s)
- Jason S John
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Nicole M Thometz
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA.,University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117, USA
| | - Katharine Boerner
- Mote Marine Laboratory & Aquarium, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Laura Denum
- Mote Marine Laboratory & Aquarium, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Traci L Kendall
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Beau P Richter
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Joseph C Gaspard
- Pittsburgh Zoo & PPG Aquarium, One Wild Place, Pittsburgh, PA 15206, USA
| | - Terrie M Williams
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
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Bodine SC, Brooks HL, Bunnett NW, Coller HA, Frey MR, Joe B, Kleyman TR, Lindsey ML, Marette A, Morty RE, Ramírez JM, Thomsen MB, Yosten GLC. An American Physiological Society cross-journal Call for Papers on "Inter-Organ Communication in Homeostasis and Disease". Am J Physiol Lung Cell Mol Physiol 2021; 321:L42-L49. [PMID: 34010064 PMCID: PMC8321848 DOI: 10.1152/ajplung.00209.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/17/2022] Open
Affiliation(s)
- Sue C Bodine
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Heddwen L Brooks
- Department of Physiology, University of Arizona College of Medicine, Tucson, Arizona
| | - Nigel W Bunnett
- Department of Molecular Pathobiology, New York University, New York, New York
| | - Hilary A Coller
- Molecular Biology Interdepartmental Program, University of California, Los Angeles, California
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California
- Department of Biological Chemistry, University of California, Los Angeles, California
| | - Mark R Frey
- The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Bina Joe
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
- Center for Hypertension and Personalized Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Merry L Lindsey
- Department of Cellular and Integrative Physiology, Center for Heart and Vascular Research, University of Nebraska Medical Center, Omaha, Nebraska
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - André Marette
- Department of Medicine, Faculty of Medicine, Cardiology Axis of the Québec Heart and Lung Institute, Hôpital Laval, Laval University, Quebec City, Québec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Québec, Canada
| | - Rory E Morty
- Department of Translational Pulmonology and the Translational Lung Research Center Heidelberg, University Hospital Heidelberg, member of the German Center for Lung Research (DZL), Heidelberg, Germany
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center, Justus Liebig University Giessen, member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Jan-Marino Ramírez
- Department of Neurological Surgery, University of Washington Medical Center, Seattle, Washington
- Center on Human Development and Disability, University of Washington, Seattle, Washington
- Center for Integrative Brain Research at the Seattle Children's Research Institute, University of Washington, Seattle, Washington
| | - Morten B Thomsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gina L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri
- Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri
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Yosten GLC. AJP-Regulatory, Integrative and Comparative Physiology: Looking Toward the Future. Am J Physiol Regul Integr Comp Physiol 2020; 319:R82-R86. [DOI: 10.1152/ajpregu.00104.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Hindle AG. Diving deep: understanding the genetic components of hypoxia tolerance in marine mammals. J Appl Physiol (1985) 2020; 128:1439-1446. [PMID: 32324472 DOI: 10.1152/japplphysiol.00846.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Marine mammals have highly specialized physiology, exhibited in many species by extreme breath-holding capabilities that allow deep dives and extended submergence. Cardiovascular control and cell-level hypoxia tolerance are key features of this phenotype. Identifying genomic signatures tied to physiology will be valuable in understanding these natural model species, which may generate translational opportunities to human diseases arising from hypoxic stress or tissue injury. Genomic analyses have now been conducted in dolphins, river dolphins, minke whales, bowhead whales, and polar bears, with multispecies studies exploring evolutionary signals across marine mammal lineages, encompassing extinct and extant divers. Single-species genome studies for sirenians do not yet exist. Extant marine mammals arose in three lineages from separate aquatic recolonizations. Their physiological specializations, along with these independent origins create an interesting case to examine convergent evolution. Although molecular mechanisms of hypoxia tolerance are not universally apparent across marine mammal genomic studies, altered evolutionary rates have been identified for genes linked to oxygen binding and transport (e.g., MB, HBA, and HBB), blood pressure control (e.g., endothelin pathway genes), and cell protection in multiple species. Despite convergent phenotypes across clades, instances of identical molecular convergence have been uncommon. Given the inherent logistical and regulatory difficulties associated with functional genetic experiments in marine mammals, several avenues of further investigation are suggested to enable validation of candidate genes for hypoxia tolerance: leveraging phylogeny to better understand convergent phenotypes; ontogenic studies to identify regulation of key genes underlying the elite, adult, hypoxia-tolerant physiology; and cell culture manipulations to understand gene function.
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Affiliation(s)
- Allyson G Hindle
- School of Life Sciences, University of Nevada, Las Vegas, Nevada
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Penso-Dolfin L, Haerty W, Hindle A, Di Palma F. microRNA profiling in the Weddell seal suggests novel regulatory mechanisms contributing to diving adaptation. BMC Genomics 2020; 21:303. [PMID: 32293246 PMCID: PMC7158035 DOI: 10.1186/s12864-020-6675-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/13/2020] [Indexed: 12/19/2022] Open
Abstract
Background The Weddell Seal (Leptonychotes weddelli) represents a remarkable example of adaptation to diving among marine mammals. This species is capable of diving > 900 m deep and remaining underwater for more than 60 min. A number of key physiological specializations have been identified, including the low levels of aerobic, lipid-based metabolism under hypoxia, significant increase in oxygen storage in blood and muscle; high blood volume and extreme cardiovascular control. These adaptations have been linked to increased abundance of key proteins, suggesting an important, yet still understudied role for gene reprogramming. In this study, we investigate the possibility that post-transcriptional gene regulation by microRNAs (miRNAs) has contributed to the adaptive evolution of diving capacities in the Weddell Seal. Results Using small RNA data across 4 tissues (brain, heart, muscle and plasma), in 3 biological replicates, we generate the first miRNA annotation in this species, consisting of 559 high confidence, manually curated miRNA loci. Evolutionary analyses of miRNA gain and loss highlight a high number of Weddell seal specific miRNAs. Four hundred sixteen miRNAs were differentially expressed (DE) among tissues, whereas 80 miRNAs were differentially expressed (DE) across all tissues between pups and adults and age differences for specific tissues were detected in 188 miRNAs. mRNA targets of these altered miRNAs identify possible protective mechanisms in individual tissues, particularly relevant to hypoxia tolerance, anti-apoptotic pathways, and nitric oxide signal transduction. Novel, lineage-specific miRNAs associated with developmental changes target genes with roles in angiogenesis and vasoregulatory signaling. Conclusions Altogether, we provide an overview of miRNA composition and evolution in the Weddell seal, and the first insights into their possible role in the specialization to diving.
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Affiliation(s)
- Luca Penso-Dolfin
- Earlham Institute, Norwich Research Park, Colney Lane, Norwich, NR47UZ, UK. .,German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
| | - Wilfried Haerty
- Earlham Institute, Norwich Research Park, Colney Lane, Norwich, NR47UZ, UK
| | - Allyson Hindle
- Massachusetts General Hospital, 55 Fruit St, Boston, MA, 02114, USA.,University of Nevada Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV, 89154, USA
| | - Federica Di Palma
- Earlham Institute, Norwich Research Park, Colney Lane, Norwich, NR47UZ, UK
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Allen KN, Vázquez-Medina JP. Natural Tolerance to Ischemia and Hypoxemia in Diving Mammals: A Review. Front Physiol 2019; 10:1199. [PMID: 31620019 PMCID: PMC6763568 DOI: 10.3389/fphys.2019.01199] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 09/03/2019] [Indexed: 12/15/2022] Open
Abstract
Reperfusion injury follows ischemia/reperfusion events occurring during myocardial infarction, stroke, embolism, and other peripheral vascular diseases. Decreased blood flow and reduced oxygen tension during ischemic episodes activate cellular pathways that upregulate pro-inflammatory signaling and promote oxidant generation. Reperfusion after ischemia recruits inflammatory cells to the vascular wall, further exacerbating oxidant production and ultimately resulting in cell death, tissue injury, and organ dysfunction. Diving mammals tolerate repetitive episodes of peripheral ischemia/reperfusion as part of the cardiovascular adjustments supporting long duration dives. These adjustments allow marine mammals to optimize the use of their body oxygen stores while diving but can result in selectively reduced perfusion to peripheral tissues. Remarkably, diving mammals show no apparent detrimental effects associated with these ischemia/reperfusion events. Here, we review the current knowledge regarding the strategies marine mammals use to suppress inflammation and cope with oxidant generation potentially derived from diving-induced ischemia/reperfusion.
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