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Russo A, Patanè GT, Putaggio S, Lombardo GE, Ficarra S, Barreca D, Giunta E, Tellone E, Laganà G. Mechanisms Underlying the Effects of Chloroquine on Red Blood Cells Metabolism. Int J Mol Sci 2024; 25:6424. [PMID: 38928131 PMCID: PMC11203553 DOI: 10.3390/ijms25126424] [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: 04/22/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Chloroquine (CQ) is a 4-aminoquinoline derivative largely employed in the management of malaria. CQ treatment exploits the drug's ability to cross the erythrocyte membrane, inhibiting heme polymerase in malarial trophozoites. Accumulation of CQ prevents the conversion of heme to hemozoin, causing its toxic buildup, thus blocking the survival of Plasmodium parasites. Recently, it has been reported that CQ is able to exert antiviral properties, mainly against HIV and SARS-CoV-2. This renewed interest in CQ treatment has led to the development of new studies which aim to explore its side effects and long-term outcome. Our study focuses on the effects of CQ in non-parasitized red blood cells (RBCs), investigating hemoglobin (Hb) functionality, the anion exchanger 1 (AE1) or band 3 protein, caspase 3 and protein tyrosine phosphatase 1B (PTP-1B) activity, intra and extracellular ATP levels, and the oxidative state of RBCs. Interestingly, CQ influences the functionality of both Hb and AE1, the main RBC proteins, affecting the properties of Hb oxygen affinity by shifting the conformational structure of the molecule towards the R state. The influence of CQ on AE1 flux leads to a rate variation of anion exchange, which begins at a concentration of 2.5 μM and reaches its maximum effect at 20 µM. Moreover, a significant decrease in intra and extracellular ATP levels was observed in RBCs pre-treated with 10 µM CQ vs. erythrocytes under normal conditions. This effect is related to the PTP-1B activity which is reduced in RBCs incubated with CQ. Despite these metabolic alterations to RBCs caused by exposure to CQ, no signs of variations in oxidative state or caspase 3 activation were recorded. Our results highlight the antithetical effects of CQ on the functionality and metabolism of RBCs, and encourage the development of new research to better understand the multiple potentiality of the drug.
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Affiliation(s)
| | - Giuseppe Tancredi Patanè
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (G.T.P.); (S.P.); (S.F.); (E.T.); (G.L.)
| | - Stefano Putaggio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (G.T.P.); (S.P.); (S.F.); (E.T.); (G.L.)
| | | | - Silvana Ficarra
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (G.T.P.); (S.P.); (S.F.); (E.T.); (G.L.)
| | - Davide Barreca
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (G.T.P.); (S.P.); (S.F.); (E.T.); (G.L.)
| | - Elena Giunta
- Virology and Microbiology AOOR Papardo-Piemonte, 98166 Messina, Italy;
| | - Ester Tellone
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (G.T.P.); (S.P.); (S.F.); (E.T.); (G.L.)
| | - Giuseppina Laganà
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (G.T.P.); (S.P.); (S.F.); (E.T.); (G.L.)
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Kowalewska PM, Milkovich SL, Goldman D, Sandow SL, Ellis CG, Welsh DG. Capillary oxygen regulates demand-supply coupling by triggering connexin40-mediated conduction: Rethinking the metabolic hypothesis. Proc Natl Acad Sci U S A 2024; 121:e2303119121. [PMID: 38349880 PMCID: PMC10895355 DOI: 10.1073/pnas.2303119121] [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: 02/26/2023] [Accepted: 12/21/2023] [Indexed: 02/15/2024] Open
Abstract
Coupling red blood cell (RBC) supply to O2 demand is an intricate process requiring O2 sensing, generation of a stimulus, and signal transduction that alters upstream arteriolar tone. Although actively debated, this process has been theorized to be induced by hypoxia and to involve activation of endothelial inwardly rectifying K+ channels (KIR) 2.1 by elevated extracellular K+ to trigger conducted hyperpolarization via connexin40 (Cx40) gap junctions to upstream resistors. This concept was tested in resting healthy skeletal muscle of Cx40-/- and endothelial KIR2.1-/- mice using state-of-the-art live animal imaging where the local tissue O2 environment was manipulated using a custom gas chamber. Second-by-second capillary RBC flow responses were recorded as O2 was altered. A stepwise drop in PO2 at the muscle surface increased RBC supply in capillaries of control animals while elevated O2 elicited the opposite response; capillaries were confirmed to express Cx40. The RBC flow responses were rapid and tightly coupled to O2; computer simulations did not support hypoxia as a driving factor. In contrast, RBC flow responses were significantly diminished in Cx40-/- mice. Endothelial KIR2.1-/- mice, on the other hand, reacted normally to O2 changes, even when the O2 challenge was targeted to a smaller area of tissue with fewer capillaries. Conclusively, microvascular O2 responses depend on coordinated electrical signaling via Cx40 gap junctions, and endothelial KIR2.1 channels do not initiate the event. These findings reconceptualize the paradigm of blood flow regulation in skeletal muscle and how O2 triggers this process in capillaries independent of extracellular K+.
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Affiliation(s)
- Paulina M Kowalewska
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Stephanie L Milkovich
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Shaun L Sandow
- School of Health, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- School of Clinical Medicine, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Christopher G Ellis
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Donald G Welsh
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5B7, Canada
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3
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Carr JMJR, Hoiland RL, Fernandes IA, Schrage WG, Ainslie PN. Recent insights into mechanisms of hypoxia-induced vasodilatation in the human brain. J Physiol 2023. [PMID: 37655827 DOI: 10.1113/jp284608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023] Open
Abstract
The cerebral vasculature manages oxygen delivery by adjusting arterial blood in-flow in the face of reductions in oxygen availability. Hypoxic cerebral vasodilatation, and the associated hypoxic cerebral blood flow reactivity, involve many vascular, erythrocytic and cerebral tissue mechanisms that mediate elevations in cerebral blood flow via micro- and macrovascular dilatation. This contemporary review focuses on in vivo human work - with reference to seminal preclinical work where necessary - on hypoxic cerebrovascular reactivity, particularly where recent advancements have been made. We provide updates with the following information: in humans, hypoxic cerebral vasodilatation is partially mediated via a - likely non-obligatory - combination of: (1) nitric oxide synthases, (2) deoxygenation-coupled S-nitrosothiols, (3) potassium channel-related vascular smooth muscle hyperpolarization, and (4) prostaglandin mechanisms with some contribution from an interrelationship with reactive oxygen species. And finally, we discuss the fact that, due to the engagement of deoxyhaemoglobin-related mechanisms, reductions in O2 content via haemoglobin per se seem to account for ∼50% of that seen with hypoxic cerebral vasodilatation during hypoxaemia. We further highlight the issue that methodological impediments challenge the complete elucidation of hypoxic cerebral reactivity mechanisms in vivo in healthy humans. Future research is needed to confirm recent advancements and to reconcile human and animal findings. Further investigations are also required to extend these findings to address questions of sex-, heredity-, age-, and disease-related differences. The final step is to then ultimately translate understanding of these mechanisms into actionable, targetable pathways for the prevention and treatment of cerebral vascular dysfunction and cerebral hypoxic brain injury.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Ryan L Hoiland
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Collaborative Entity for Researching Brain Ischemia (CEREBRI), University of British Columbia, Vancouver, British Columbia, Canada
| | - Igor A Fernandes
- Department of Health and Kinesiology, Purdue University, Indiana, USA
| | - William G Schrage
- Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
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Bonanno FG. Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies. J Clin Med 2022; 12:jcm12010260. [PMID: 36615060 PMCID: PMC9821021 DOI: 10.3390/jcm12010260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/22/2022] [Accepted: 11/27/2022] [Indexed: 12/30/2022] Open
Abstract
Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.
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Affiliation(s)
- Fabrizio G Bonanno
- Department of Surgery, Polokwane Provincial Hospital, Cnr Hospital & Dorp Street, Polokwane 0700, South Africa
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5
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Misiti F. Sphingosine Increases ATP Release From Red Blood Cells. Open Biochem J 2022. [DOI: 10.2174/1874091x-v16-e2204210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
RBC plays a pivotal role in oxygen delivery, improving distribution where it needs. When RBC enters a low oxygen area, a mechanism mediated by a signaling pathway releases ATP, responsible for vasodilatation.
Objective:
Clarify the potential role of sphingosine on the release of ATP from RBC.
Methods:
ATP release increases after sphingosine exposure in RBC under low oxygen conditions. ATP release in deoxygenated RBC shows data like that of control RBC: (1) RBC after band 3 modification by 4,4'- diisothio-cyanato-stilbene- 2,2'-disulphonic acid (DIDS); (2) CO-treated RBC.
Unlike phosphofructokinase, adenylate cyclase (AC) activity increases after exposure to sphingosine.
Results:
We show that cAMP synthesis and ATP release are not failed in sphingosine-treated red blood cells in response to incubation with mastoparan 7, forskolin plus 3-isobutyl-1-methyl xanthine, agents that stimulate cAMP synthesis.
Conclusion:
Deoxy-hemoglobin, band 3, and AC are involved in the signaling pathway responsible for ATP released after sphingosine exposure.
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6
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Misiti F. Sphingosine Increases ATP Release From Red Blood Cells. Open Biochem J 2022. [DOI: 10.2174/874091x-v16-e2204210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
RBC plays a pivotal role in oxygen delivery, improving distribution where it needs. When RBC enters a low oxygen area, a mechanism mediated by a signaling pathway releases ATP, responsible for vasodilatation.
Objective:
Clarify the potential role of sphingosine on the release of ATP from RBC.
Methods:
ATP release increases after sphingosine exposure in RBC under low oxygen conditions. ATP release in deoxygenated RBC shows data like that of control RBC: (1) RBC after band 3 modification by 4,4'- diisothio-cyanato-stilbene- 2,2'-disulphonic acid (DIDS); (2) CO-treated RBC.
Unlike phosphofructokinase, adenylate cyclase (AC) activity increases after exposure to sphingosine.
Results:
We show that cAMP synthesis and ATP release are not failed in sphingosine-treated red blood cells in response to incubation with mastoparan 7, forskolin plus 3-isobutyl-1-methyl xanthine, agents that stimulate cAMP synthesis.
Conclusion:
Deoxy-hemoglobin, band 3, and AC are involved in the signaling pathway responsible for ATP released after sphingosine exposure.
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Racine ML, Terwoord JD, Ketelhut NB, Bachman NP, Richards JC, Luckasen GJ, Dinenno FA. Rho-kinase inhibition improves haemodynamic responses and circulating ATP during hypoxia and moderate intensity handgrip exercise in healthy older adults. J Physiol 2022; 600:3265-3285. [PMID: 35575293 PMCID: PMC9288513 DOI: 10.1113/jp282730] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 05/09/2022] [Indexed: 11/21/2022] Open
Abstract
Abstract Skeletal muscle haemodynamics and circulating adenosine triphosphate (ATP) responses during hypoxia and exercise are blunted in older (OA) vs. young (YA) adults, which may be associated with impaired red blood cell (RBC) ATP release. Rho‐kinase inhibition improves deoxygenation‐induced ATP release from OA isolated RBCs. We tested the hypothesis that Rho‐kinase inhibition (via fasudil) in vivo would improve local haemodynamic and ATP responses during hypoxia and exercise in OA. Healthy YA (25 ± 3 years; n = 12) and OA (65 ± 5 years; n = 13) participated in a randomized, double‐blind, placebo‐controlled, crossover study on two days (≥5 days between visits). A forearm deep venous catheter was used to administer saline/fasudil and sample venous plasma ATP ([ATP]V). Forearm vascular conductance (FVC) and [ATP]V were measured at rest, during isocapnic hypoxia (80% SpO2), and during graded rhythmic handgrip exercise that was similar between groups (5, 15 and 25% maximum voluntary contraction (MVC)). Isolated RBC ATP release was measured during normoxia/hypoxia. With saline, ΔFVC was lower (P < 0.05) in OA vs. YA during hypoxia (∼60%) and during 15 and 25% MVC (∼25–30%), and these impairments were abolished with fasudil. Similarly, [ATP]V and ATP effluent responses from normoxia to hypoxia and rest to 25% MVC were lower in OA vs. YA and improved with fasudil (P < 0.05). Isolated RBC ATP release during hypoxia was impaired in OA vs. YA (∼75%; P < 0.05), which tended to improve with fasudil in OA (P = 0.082). These data suggest Rho‐kinase inhibition improves haemodynamic responses to hypoxia and moderate intensity exercise in OA, which may be due in part to improved circulating ATP.
![]() Key points Skeletal muscle blood flow responses to hypoxia and exercise are impaired with age. Blunted increases in circulating ATP, a vasodilator, in older adults may contribute to age‐related impairments in haemodynamics. Red blood cells (RBCs) are a primary source of circulating ATP, and treating isolated RBCs with a Rho‐kinase inhibitor improves age‐related impairments in deoxygenation‐induced RBC ATP release. In this study, treating healthy older adults systemically with the Rho‐kinase inhibitor fasudil improved blood flow and circulating ATP responses during hypoxia and moderate intensity handgrip exercise compared to young adults, and also tended to improve isolated RBC ATP release. Improved blood flow regulation with fasudil was also associated with increased skeletal muscle oxygen delivery during hypoxia and exercise in older adults. This is the first study to demonstrate that Rho‐kinase inhibition can significantly improve age‐related impairments in haemodynamic and circulating ATP responses to physiological stimuli, which may have therapeutic implications.
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Affiliation(s)
- Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Nathaniel B Ketelhut
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Nate P Bachman
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies, University of Colorado Health, Loveland, CO, 80538, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
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Spectroscopy detects skeletal muscle microvascular dysfunction during onset of sepsis in a rat fecal peritonitis model. Sci Rep 2022; 12:6339. [PMID: 35428849 PMCID: PMC9012880 DOI: 10.1038/s41598-022-10208-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 03/15/2022] [Indexed: 01/20/2023] Open
Abstract
Sepsis is a dysregulated host inflammatory response to infection potentially leading to life-threatening organ dysfunction. The objectives of this study were to determine whether early microvascular dysfunction (MVD) in skeletal muscle can be detected as dynamic changes in microvascular hemoglobin (MVHb) levels using spectroscopy and whether MVD precedes organ histopathology in septic peritonitis. Skeletal muscle of male Sprague-Dawley rats was prepared for intravital microscopy. After intraperitoneal injection of fecal slurry or saline, microscopy and spectroscopy recordings were taken for 6 h. Capillary red blood cell (RBC) dynamics and SO2 were quantified from digitized microscopy frames and MVHb levels were derived from spectroscopy data. Capillary RBC dynamics were significantly decreased by 4 h after peritoneal infection and preceded macrohemodynamic changes. At the same time, low-frequency oscillations in MVHb levels exhibited a significant increase in Power in parts of the muscle and resembled oscillations in RBC dynamics and SO2. After completion of microscopy, tissues were collected. Histopathological alterations were not observed in livers, kidneys, brains, or muscles 6 h after induction of peritonitis. The findings of this study show that, in our rat model of sepsis, MVD occurs before detectable organ histopathology and includes ~ 30-s oscillations in MVHb. Our work highlights MVHb oscillations as one of the indicators of MVD onset and provides a foundation for the use of non-invasive spectroscopy to continuously monitor MVD in septic patients.
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Is NMDA-Receptor-Mediated Oxidative Stress in Mitochondria of Peripheral Tissues the Essential Factor in the Pathogenesis of Hepatic Encephalopathy? J Clin Med 2022; 11:jcm11030827. [PMID: 35160278 PMCID: PMC8836479 DOI: 10.3390/jcm11030827] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of increased ammonia-mediated brain dysfunction caused by impaired hepatic detoxification or when the blood bypasses the liver. Ammonia-activated signal transduction pathways of hyperactivated NMDA receptors (NMDAR) are shown to trigger a cascade of pathological reactions in the brain, leading to oxidative stress. NMDARs outside the brain are widely distributed in peripheral tissues, including the liver, heart, pancreas, and erythrocytes. To determine the contribution of these receptors to ammonia-induced oxidative stress in peripheral tissues, it is relevant to investigate if there are any ammonia-related changes in antioxidant enzymes and free radical formation and whether blockade of NMDARs prevents these changes. Methods: Hyperammonemia was induced in rats by ammonium acetate injection. Oxidative stress was measured as changes in antioxidant enzyme activities and O2•− and H2O2 production by mitochondria isolated from the tissues and cells mentioned above. The effects of the NMDAR antagonist MK-801 on oxidative stress markers and on tissue ammonia levels were evaluated. Results: Increased ammonia levels in erythrocytes and mitochondria isolated from the liver, pancreas, and heart of hyperammonemic rats are shown to cause tissue-specific oxidative stress, which is prevented completely (or partially in erythrocyte) by MK-801. Conclusions: These results support the view that the pathogenesis of HE is multifactorial and that ammonia-induced multiorgan oxidative stress-mediated by activation of NMDAR is an integral part of the disease and, therefore, the toxic effects of ammonia in НЕ may be more global than initially expected.
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Physiological Function during Exercise and Environmental Stress in Humans-An Integrative View of Body Systems and Homeostasis. Cells 2022; 11:cells11030383. [PMID: 35159193 PMCID: PMC8833916 DOI: 10.3390/cells11030383] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/26/2022] Open
Abstract
Claude Bernard’s milieu intérieur (internal environment) and the associated concept of homeostasis are fundamental to the understanding of the physiological responses to exercise and environmental stress. Maintenance of cellular homeostasis is thought to happen during exercise through the precise matching of cellular energetic demand and supply, and the production and clearance of metabolic by-products. The mind-boggling number of molecular and cellular pathways and the host of tissues and organ systems involved in the processes sustaining locomotion, however, necessitate an integrative examination of the body’s physiological systems. This integrative approach can be used to identify whether function and cellular homeostasis are maintained or compromised during exercise. In this review, we discuss the responses of the human brain, the lungs, the heart, and the skeletal muscles to the varying physiological demands of exercise and environmental stress. Multiple alterations in physiological function and differential homeostatic adjustments occur when people undertake strenuous exercise with and without thermal stress. These adjustments can include: hyperthermia; hyperventilation; cardiovascular strain with restrictions in brain, muscle, skin and visceral organs blood flow; greater reliance on muscle glycogen and cellular metabolism; alterations in neural activity; and, in some conditions, compromised muscle metabolism and aerobic capacity. Oxygen supply to the human brain is also blunted during intense exercise, but global cerebral metabolism and central neural drive are preserved or enhanced. In contrast to the strain seen during severe exercise and environmental stress, a steady state is maintained when humans exercise at intensities and in environmental conditions that require a small fraction of the functional capacity. The impact of exercise and environmental stress upon whole-body functions and homeostasis therefore depends on the functional needs and differs across organ systems.
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11
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Misiti F, Carelli-Alinovi C, Rodio A. ATP release from erythrocytes: A role of adenosine1. Clin Hemorheol Microcirc 2022; 80:61-71. [DOI: 10.3233/ch-221379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND: The oxygen required to meet metabolic needs of all tissues is delivered by the red blood cell, a small, flexible cell which, in mammals, is devoid of a nucleus and mitochondria. Despite its simple appearance, this cell has an important role in its own distribution, enabling the delivery of oxygen to precisely meet localized metabolic need. When red blood cells enter in hypoxic area, a signalling pathway is activated within the cell, resulting in the release of ATP in amounts adequate to activate purinergic receptors on vascular endothelium, which trigger secretion of nitric oxide and other factors resulting in vasodilatation. OBJECTIVE: The present study investigates the effect of adenosine exposure on this molecular mechanism. METHODS AND RESULTS: We report that RBC in the presence of adenosine in low oxygen conditions, ATP release increase after 24 h exposure. Adenosine induced-ATP release in deoxygenated red blood cell show data similar to that of RBC in high oxygen conditions: (1) RBC after band 3 modification by 4,4′- diisothio-cyanatostilbene- 2,2′-disulphonic acid; (2) CO-treated RBC. In the presence of Sphingosine kinase (SphK1) inhibitor, adenosine mediated effects on ATP release were abolished. Activity of adenylate cyclase increase following to adenosine exposure, on the contrary red cell phosphofructokinase is not modified within the RBC in the presence of adenosine. CONCLUSION: Our data support involvement of band 3/deoxyHb binding and adenylate cyclase in the pathway responsible for ATP release from RBC following exposure to adenosine.
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Affiliation(s)
- Francesco Misiti
- Human, Social and Health Department, University of Cassino and Lazio Meridionale, V. S. Angelo, Loc. Folcara, Cassino (FR), Italy
| | - Cristiana Carelli-Alinovi
- Biochemistry and Clinical Biochemistry Institute, Catholic University, School of Medicine, L. go F. Rome, Italy
| | - Angelo Rodio
- Human, Social and Health Department, University of Cassino and Lazio Meridionale, V. S. Angelo, Loc. Folcara, Cassino (FR), Italy
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12
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Ghonaim NW, Fraser GM, Goldman D, Milkovich S, Yang J, Ellis CG. Evidence for role of capillaries in regulation of skeletal muscle oxygen supply. Microcirculation 2021; 28:e12699. [PMID: 33853202 DOI: 10.1111/micc.12699] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/23/2021] [Accepted: 03/22/2021] [Indexed: 11/30/2022]
Abstract
How oxygen (O2 ) supply to capillaries is regulated to match the tissue's demand is unknown. Erythrocytes have been proposed as sensors in this regulatory mechanism since they release ATP, a vasodilator, in an oxygen saturation (SO2 )-dependent manner. ATP causes hyperpolarization of endothelial cells resulting in conducted vasodilation to arterioles. OBJECTIVE We propose individual capillary units can regulate their own O2 supply by direct communication to upstream arterioles via electrically coupled endothelium. METHODS To test this hypothesis, we developed a transparent micro-exchange device for localized O2 exchange with surface capillaries of intact tissue. The device was fabricated with an O2 permeable micro-outlet 0.2 × 1.0 mm. Experiments were performed on rat extensor digitorum longus (EDL) muscle using dual wavelength video microscopy to measure capillary hemodynamics and erythrocyte SO2 . Responses to local O2 perturbations were measured with only capillaries positioned over the micro-outlet. RESULTS Step changes in the gas mixture %O2 caused physiological changes in erythrocyte SO2 , and appropriate changes in flow to offset the O2 challenge if at least 3-4 capillaries were stimulated. CONCLUSION These results support our hypothesis that individual capillary units play a role in regulating their erythrocyte supply in response to a changing O2 environment.
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Affiliation(s)
- Nour W Ghonaim
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, ON, Canada
| | - Graham M Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Daniel Goldman
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, ON, Canada.,Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada
| | - Stephanie Milkovich
- Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada.,Schulich School of Medicine & Dentistry, Robarts Research Institute, The University of Western Ontario, London, ON, Canada
| | - Jun Yang
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, ON, Canada.,Department of Mechanical and Materials Engineering, The University of Western Ontario, London, ON, Canada
| | - Christopher G Ellis
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, ON, Canada.,Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada.,Schulich School of Medicine & Dentistry, Robarts Research Institute, The University of Western Ontario, London, ON, Canada
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13
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Thorn CE, Adio AO, Fox RH, Gardner AM, Winlove CP, Shore AC. Intermittent compression induces transitory hypoxic stimuli, upstream vasodilation and enhanced perfusion of skin capillaries, independent of age and diabetes. J Appl Physiol (1985) 2021; 130:1072-1084. [PMID: 33571053 DOI: 10.1152/japplphysiol.00657.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The benefit of enhanced shear stress to the vascular endothelium has been well-documented in conduit arteries but is less understood in skin microcirculation. The aim of this study was to provide physiological evidence of the vascular changes in skin microcirculation induced by intermittent pneumatic compression (IPC) of 1 s cuff inflation (130 mmHg) every 20 s to the palm of the hand for 30 min. The oxygenation and hemodynamics of dorsal mid-phalangeal finger skin microcirculation were assessed by laser Doppler fluximetry and reflectance spectroscopy before, during, and after IPC in 15 young (18-39 years old) and 39 older (40-80 years old) controls and 32 older subjects with type 2 diabetes mellitus. Each individual cuff inflation induced: 1) brief surge in flux immediately after cuff deflation followed by 2) transitory reduction in blood oxygen for ∼4 s, and 3) a second increase in perfusion and oxygenation of the microcirculation peaking ∼11 s after cuff deflation in all subject groups. With no significant change in blood volume observed by reflectance spectroscopy, despite the increased shear stress at the observed site, this second peak in flux and blood oxygen suggests a delayed vasoactive response upstream inducing increased arterial influx in the microcirculation that was higher in older controls and subjects with diabetes compared to young controls (P < 0.001, P < 0.001, respectively) and achieving maximum capillary recruitment in all subject groups. Transitory hypoxic stimuli with conducted vasodilation may be a mechanism through which IPC enhances capillary perfusion in skin microcirculation independent of age and type 2 diabetes mellitus.NEW & NOTEWORTHY This study demonstrates that hand intermittent pneumatic compression evokes transitory hypoxic stimuli in distal finger skin microcirculation inducing vasodilation of arterial inflow vessels, enhanced perfusion, and maximum capillary recruitment in young and older subjects and older subjects with type 2 diabetes mellitus. Enhanced shear stress in the microcirculation did not appear to induce local skin vasodilation.
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Affiliation(s)
- Clare E Thorn
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Aminat O Adio
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Roger H Fox
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - A Michael Gardner
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - C Peter Winlove
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Angela C Shore
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
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14
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Hoiland RL, Caldwell HG, Howe CA, Nowak-Flück D, Stacey BS, Bailey DM, Paton JFR, Green DJ, Sekhon MS, Macleod DB, Ainslie PN. Nitric oxide is fundamental to neurovascular coupling in humans. J Physiol 2020; 598:4927-4939. [PMID: 32785972 DOI: 10.1113/jp280162] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/06/2020] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS Preclinical models have demonstrated that nitric oxide is a key component of neurovascular coupling; this has yet to be translated to humans. We conducted two separate protocols utilizing intravenous infusion of a nitric oxide synthase inhibitor and isovolumic haemodilution to assess the influence of nitric oxide on neurovascular coupling in humans. Isovolumic haemodilution did not alter neurovascular coupling. Intravenous infusion of a nitric oxide synthase inhibitor reduced the neurovascular coupling response by ∼30%, indicating that nitric oxide is integral to neurovascular coupling in humans. ABSTRACT Nitric oxide is a vital neurovascular signalling molecule in preclinical models, yet the mechanisms underlying neurovascular coupling (NVC) in humans have yet to be elucidated. To investigate the contribution of nitric oxide to NVC in humans, we utilized a visual stimulus paradigm to elicit an NVC response in the posterior cerebral circulation. Two distinct mechanistic interventions were conducted on young healthy males: (1) NVC was assessed during intravenous infusion of saline (placebo) and the non-selective competitive nitric oxide synthase inhibitor NG -monomethyl-l-arginine (l-NMMA, 5 mg kg-1 bolus & subsequent 50 μg kg-1 min-1 maintenance dose; n = 10). The order of infusion was randomized, counterbalanced and single blinded. A subset of participants in this study (n = 4) underwent a separate intervention with phenylephrine infusion to independently consider the influence of blood pressure changes on NVC (0.1-0.6 μg kg-1 min-1 constant infusion). (2) NVC was assessed prior to and following isovolumic haemodilution, whereby 20% of whole blood was removed and replaced with 5% human serum albumin to reduce haemoglobin concentration (n = 8). For both protocols, arterial and internal jugular venous blood samples were collected at rest and coupled with volumetric measures of cerebral blood flow (duplex ultrasound) to quantify resting cerebral metabolic parameters. l-NMMA elicited a 30% reduction in the peak (P = 0.01), but not average (P = 0.11), NVC response. Neither phenylephrine nor haemodilution influenced NVC. Nitric oxide signalling is integral to NVC in humans, providing a new direction for research into pharmacological treatment of humans with dementia.
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Affiliation(s)
- Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, V1V 1V7, Canada.,Department of Anesthesiology, Pharmacology, and Therapeutics, Vancouver General Hospital, 899 West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, V1V 1V7, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, V1V 1V7, Canada
| | - Daniela Nowak-Flück
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, V1V 1V7, Canada
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, CF37 4BB, UK
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, CF37 4BB, UK
| | - Julian F R Paton
- Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Park Road, Grafton, Auckland, 1142, New Zealand
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Nedlands, Western Australia, 6009, Australia
| | - Mypinder S Sekhon
- Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, West 12th Avenue, University of British Columbia, Vancouver, BC, V5Z 1M9, Canada
| | - David B Macleod
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27708, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, V1V 1V7, Canada
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15
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Abstract
Oxygen (O2) delivery, which is fundamental to supporting patients with critical illness, is a function of blood O2 content and flow. This article reviews red blood cell (RBC) physiology and dysfunction relevant to disordered O2 delivery in the critically ill. Flow is the focus of O2 delivery regulation: O2 content is relatively fixed, whereas flow fluctuates greatly. Thus, blood flow volume and distribution vary to maintain coupling between O2 delivery and demand. This article reviews conventional RBC physiology influencing O2 delivery and introduces a paradigm for O2 delivery homeostasis based on coordinated gas transport and vascular signaling by RBCs.
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Affiliation(s)
- Stephen Rogers
- Department of Pediatrics, Center for Blood Oxygen Transport and Hemostasis, University of Maryland School of Medicine, HSF III, 8th Floor, 670 West Baltimore Street, Baltimore, MD 21204, USA
| | - Allan Doctor
- Department of Pediatrics, Center for Blood Oxygen Transport and Hemostasis, University of Maryland School of Medicine, HSF III, 8th Floor, 670 West Baltimore Street, Baltimore, MD 21204, USA.
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16
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Ugurel E, Piskin S, Aksu AC, Eser A, Yalcin O. From Experiments to Simulation: Shear-Induced Responses of Red Blood Cells to Different Oxygen Saturation Levels. Front Physiol 2020; 10:1559. [PMID: 32038272 PMCID: PMC6987081 DOI: 10.3389/fphys.2019.01559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 12/11/2019] [Indexed: 11/13/2022] Open
Abstract
Red blood cells (RBC) carry and deliver oxygen (O2) to peripheral tissues through different microcirculatory regions where they are exposed to various levels of shear stress (SS). O2 affinity of hemoglobin (Hb) decreases as the blood enters the microcirculation. This phenomenon determines Hb interactions with RBC membrane proteins that can further regulate the structure of cytoskeleton and affect the mechanical properties of cells. The goal of this study is to evaluate shear-induced RBC deformability and simulate RBC dynamics in blood flow under oxygenated and deoxygenated conditions. Venous blood samples from healthy donors were oxygenated with ambient air or deoxygenated with 100% nitrogen gas for 10 min and immediately applied into an ektacytometer (LORRCA). RBC deformability was measured before and after the application of continuous 5 Pa SS for 300 s by LORRCA and recorded as elongation index (EI) values. A computational model was generated for the simulation of blood flow in a real carotid artery section. EI distribution throughout the artery and its relationships with velocity, pressure, wall SS and viscosity were determined by computational tools. RBC deformability significantly increased in deoxygenation compared to oxygenated state both before and after 5 Pa SS implementation (p < 0.0001). However, EI values after continuous SS were not significant at higher SS levels (>5.15 Pa) in deoxygenated condition. Simulation results revealed that the velocity gradient dominates the generation of SS and the shear thinning effect of blood has a minor effect on it. Distribution of EI was calculated during oxygenation/deoxygenation which is 5-10 times higher around the vessel wall compared to the center of the lumen for sections of the pulsatile flow profile. The extent of RBC deformability increases as RBCs approach to the vessel wall in a real 3D artery model and this increment is higher for deoxygenated condition compared to the oxygenated state. Hypoxia significantly increases shear-induced RBC deformability. RBCs could regulate their own mechanical properties in blood flow by increasing their deformability in hypoxic conditions. Computational tools can be applied for defining hypoxia-mediated RBC deformability changes to monitor blood flow in hypoxic tissues.
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Affiliation(s)
- Elif Ugurel
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey.,Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | - Senol Piskin
- Department of Mechanical Engineering, Istinye University, Istanbul, Turkey.,Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Ali Cenk Aksu
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey.,Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | - Aysenur Eser
- Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey.,Graduate School of Biomedical Sciences and Engineering, Koç University, Istanbul, Turkey
| | - Ozlem Yalcin
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey.,Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
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17
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Asaro RJ, Zhu Q. Vital erythrocyte phenomena: what can theory, modeling, and simulation offer? Biomech Model Mechanobiol 2020; 19:1361-1388. [DOI: 10.1007/s10237-020-01302-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 01/22/2020] [Indexed: 12/14/2022]
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18
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Didier KD, Hammer SM, Alexander AM, Caldwell JT, Sutterfield SL, Smith JR, Ade CJ, Barstow TJ. Microvascular blood flow during vascular occlusion tests assessed by diffuse correlation spectroscopy. Exp Physiol 2019; 105:201-210. [DOI: 10.1113/ep087866] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/29/2019] [Indexed: 01/13/2023]
Affiliation(s)
- Kaylin D. Didier
- Department of Kinesiology Kansas State University Manhattan KS USA
| | - Shane M. Hammer
- Department of Kinesiology Kansas State University Manhattan KS USA
| | | | | | | | - Joshua R. Smith
- Department of Kinesiology Kansas State University Manhattan KS USA
| | - Carl J. Ade
- Department of Kinesiology Kansas State University Manhattan KS USA
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19
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Soslau G. Extracellular adenine compounds within the cardiovascular system: Their source, metabolism and function. MEDICINE IN DRUG DISCOVERY 2019. [DOI: 10.1016/j.medidd.2020.100018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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20
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Tognoni E, Orsini P, Pellegrino M. Nonlinear indentation of single human erythrocytes under application of a localized mechanical force. Micron 2019; 127:102760. [PMID: 31614267 DOI: 10.1016/j.micron.2019.102760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/24/2019] [Accepted: 09/26/2019] [Indexed: 12/25/2022]
Abstract
Despite the accepted notion that erythrocytes are uniquely deformable cells, the apparent Young's modulus values reported in the literature do not differ so much from those of other cells. We devised to measure the local deformability of living immobilized human erythrocytes at a low force, in contact-free mode, using an application of Scanning Ion Conductance Microscopy (SICM) previously developed in our laboratory. Reversible indentations were induced by forces of up to few hundreds pN. The indentation did not grow linearly with the force. The apparent Young's modulus varied from 0.2 to 1.5 kPa applying forces from 20 to 500 pN on a cell surface area of about 0.2 μm2, exhibiting a progressive stiffening at increasing force. Control measurements showed that A549 cells exhibit a constant value of the apparent Young's modulus (about 2 kPa) for forces up to about 800 pN. These findings show that SICM is a suitable tool to investigate cell mechanical properties, when forces in the range of tens of pN are required, in the absence of mechanical contact between probe and sample. The nonlinear deformation of the erythrocyte has to be taken into account in modeling the complex regulation mechanism of the microvascular beds.
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Affiliation(s)
- Elisabetta Tognoni
- Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), Via Moruzzi 1, 56124, Pisa, Italy.
| | - Paolo Orsini
- Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Università di Pisa, via S. Zeno 31, 56127, Pisa, Italy
| | - Mario Pellegrino
- Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), Via Moruzzi 1, 56124, Pisa, Italy
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21
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Racine ML, Dinenno FA. Reduced deformability contributes to impaired deoxygenation-induced ATP release from red blood cells of older adult humans. J Physiol 2019; 597:4503-4519. [PMID: 31310005 DOI: 10.1113/jp278338] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 07/15/2019] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Red blood cells (RBCs) release ATP in response to deoxygenation, which can increase blood flow to help match oxygen supply with tissue metabolic demand. This release of ATP is impaired in RBCs from older adults, but the underlying mechanisms are unknown. In this study, improving RBC deformability in older adults restored deoxygenation-induced ATP release, whereas decreasing RBC deformability in young adults reduced ATP release to the level of that of older adults. In contrast, treating RBCs with a phosphodiesterase 3 inhibitor did not affect ATP release in either age group, possibly due to intact intracellular signalling downstream of deoxygenation as indicated by preserved cAMP and ATP release responses to pharmacological Gi protein activation in RBCs from older adults. These findings are the first to demonstrate that the age-related decrease in RBC deformability is a primary mechanism of impaired deoxygenation-induced ATP release, which may have implications for treating impaired vascular control with advancing age. ABSTRACT In response to haemoglobin deoxygenation, red blood cells (RBCs) release ATP, which binds to endothelial purinergic receptors and stimulates vasodilatation. This ATP release is impaired in RBCs from older vs. young adults, but the underlying mechanisms are unknown. Using isolated RBCs from young (24 ± 1 years) and older (65 ± 2 years) adults, we tested the hypothesis that age-related changes in RBC deformability (Study 1) and cAMP signalling (Study 2) contribute to the impairment. RBC ATP release during normoxia ( P O 2 ∼112 mmHg) and hypoxia ( P O 2 ∼20 mmHg) was quantified with the luciferin-luciferase technique following RBC incubation with Y-27632 (Rho-kinase inhibitor to increase deformability), diamide (cell-stiffening agent), cilostazol (phosphodiesterase 3 inhibitor), or vehicle control. The mean change in RBC ATP release from normoxia to hypoxia in control conditions was significantly impaired in older vs. young (∼50% vs. ∼120%; P < 0.05). RBC deformability was also lower in older vs. young as indicated by a higher RBC transit time (RCTT) measured by blood filtrometry (RCTT: 8.541 ± 0.050 vs. 8.234 ± 0.098 a.u., respectively; P < 0.05). Y-27632 improved RBC deformability (RCTT: 8.228 ± 0.083) and ATP release (111.7 ± 17.2%) in older and diamide decreased RBC deformability (RCTT: 8.955 ± 0.114) and ATP release (67.4 ± 11.8%) in young (P < 0.05), abolishing the age group differences (P > 0.05). Cilostazol did not change ATP release in either age group (P > 0.05), and RBC cAMP and ATP release to pharmacological Gi protein activation was similar in both groups (P > 0.05). We conclude that decreased RBC deformability is a primary contributor to age-related impairments in RBC ATP release, which may have implications for impaired vascular control with advancing age.
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Affiliation(s)
- Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Cardiovascular Research Center, Colorado State University, Fort Collins, CO, 80523, USA
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22
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Kosmachevskaya OV, Topunov AF. Alternate and Additional Functions of Erythrocyte Hemoglobin. BIOCHEMISTRY (MOSCOW) 2019; 83:1575-1593. [PMID: 30878032 DOI: 10.1134/s0006297918120155] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The review discusses pleiotropic effects of erythrocytic hemoglobin (Hb) and their significance for human health. Hemoglobin is mostly known as an oxygen carrier, but its biochemical functions are not limited to this. The following aspects of Hb functioning are examined: (i) catalytic functions of the heme component (nitrite reductase, NO dioxygenase, monooxygenase, alkylhydroperoxidase) and of the apoprotein (esterase, lipoxygenase); (ii) participation in nitric oxide metabolism; (iii) formation of membrane-bound Hb and its role in the regulation of erythrocyte metabolism; (iv) physiological functions of Hb catabolic products (iron, CO, bilirubin, peptides). Special attention is given to Hb participation in signal transduction in erythrocytes. The relationships between various erythrocyte metabolic parameters, such as oxygen status, ATP formation, pH regulation, redox balance, and state of the cytoskeleton are discussed with regard to Hb. Hb polyfunctionality can be considered as a manifestation of the principle of biochemical economy.
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Affiliation(s)
- O V Kosmachevskaya
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - A F Topunov
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia.
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23
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Groen MB, Knudsen TA, Finsen SH, Pedersen BK, Hellsten Y, Mortensen SP. Reduced skeletal-muscle perfusion and impaired ATP release during hypoxia and exercise in individuals with type 2 diabetes. Diabetologia 2019; 62:485-493. [PMID: 30607464 DOI: 10.1007/s00125-018-4790-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Plasma ATP is a potent vasodilator and is thought to play a role in the local regulation of blood flow. Type 2 diabetes is associated with reduced tissue perfusion. We aimed to examine whether individuals with type 2 diabetes have reduced plasma ATP concentrations compared with healthy control participants (case-control design). METHODS We measured femoral arterial and venous plasma ATP levels with the intravascular microdialysis technique during normoxia, hypoxia and one-legged knee-extensor exercise (10 W and 30 W) in nine participants with type 2 diabetes and eight control participants. In addition, we infused acetylcholine (ACh), sodium nitroprusside (SNP) and ATP into the femoral artery to assess vascular function and ATP signalling. RESULTS Individuals with type 2 diabetes had a lower leg blood flow (LBF; 2.9 ± 0.1 l/min) compared with the control participants (3.2 ± 0.1 l/min) during exercise (p < 0.05), in parallel with lower venous plasma ATP concentration (205 ± 35 vs 431 ± 72 nmol/l; p < 0.05). During systemic hypoxia, LBF increased from 0.35 ± 0.04 to 0.54 ± 0.06 l/min in control individuals, whereas it did not increase (0.25 ± 0.04 vs 0.31 ± 0.03 l/min) in the those with type 2 diabetes and was lower than in the control individuals (p < 0.05). Hypoxia increased venous plasma ATP levels in both groups (p < 0.05), but the increase was higher in control individuals (90 ± 26 nmol/l) compared to those with type 2 diabetes (18 ± 5 nmol/l). LBF and vascular conductance were lower during ATP (0.15 and 0.4 μmol min-1 [kg leg mass]-1) and ACh (100 μg min-1 [kg leg mass]-1) infusion in individuals with type 2 diabetes compared with the control participants (p < 0.05), whereas there was no difference during SNP infusion. CONCLUSIONS/INTERPRETATION These findings demonstrate that individuals with type 2 diabetes have lower plasma ATP concentrations during exercise and hypoxia compared with control individuals, and this occurs in parallel with lower blood flow. Moreover, individuals with type 2 diabetes have a reduced vasodilatory response to infused ATP. These impairments in the ATP system are both likely to contribute to the reduced tissue perfusion associated with type 2 diabetes. TRIAL REGISTRATION ClinicalTrials.gov NCT02001766.
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Affiliation(s)
- Martin B Groen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Winslowparken 21 3, 5000, Odense, Denmark
| | - Trine A Knudsen
- Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Stine H Finsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Winslowparken 21 3, 5000, Odense, Denmark
| | - Bente K Pedersen
- Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Stefan P Mortensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Winslowparken 21 3, 5000, Odense, Denmark.
- Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark.
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24
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ATP in red blood cells as biomarker for sepsis in humans. Med Hypotheses 2019; 124:84-86. [PMID: 30798924 DOI: 10.1016/j.mehy.2019.02.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/14/2018] [Accepted: 02/02/2019] [Indexed: 12/25/2022]
Abstract
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to an infection. Due to the lack of causative immune treatment, mortality of sepsis remains at a high level and represents one of the main disease burdens globally. Adenosine 5' triphosphate (ATP) levels in red blood cells (RBC) are modulated by various factors during sepsis, including a decrease in ATP production, an increase in ATP catabolism and alterations in ATP release. Therefore, we hypothesize that intracellular ATP levels in RBC can serve as potential biomarker for sepsis and support sepsis diagnosis. This will facilitate early treatment and could improve the outcome of this serious condition.
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25
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Giles AV, Sun J, Femnou AN, Kuzmiak-Glancy S, Taylor JL, Covian R, Murphy E, Balaban RS. Paradoxical arteriole constriction compromises cytosolic and mitochondrial oxygen delivery in the isolated saline-perfused heart. Am J Physiol Heart Circ Physiol 2018; 315:H1791-H1804. [PMID: 30311498 DOI: 10.1152/ajpheart.00493.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The isolated saline-perfused heart is used extensively to study cardiac physiology. Previous isolated heart studies have demonstrated lower tissue oxygenation compared with in vivo hearts based on myoglobin oxygenation and the mitochondrial redox state. These data, consistent with small anoxic regions, suggest that the homeostatic balance between work and oxygen delivery is impaired. We hypothesized that these anoxic regions are caused by inadequate local perfusion due to a paradoxical arteriole constriction generated by a disrupted vasoregulatory network. We tested this hypothesis by applying two exogenous vasodilatory agents, adenosine and cromakalim, to relax vascular tone in an isolated, saline-perfused, working rabbit heart. Oxygenation was monitored using differential optical transmission spectroscopy and full spectral fitting. Increases in coronary flow over control with adenosine (27 ± 4 ml/min) or cromakalim (44 ± 4 ml/min) were associated with proportional spectral changes indicative of myoglobin oxygenation and cytochrome oxidase (COX) oxidation, consistent with a decrease in tissue anoxia. Quantitatively, adenosine decreased deoxymyoglobin optical density (OD) across the wall by 0.053 ± 0.008 OD, whereas the reduced form of COX was decreased by 0.039 ± 0.005 OD. Cromakalim was more potent, decreasing deoxymyoglobin and reducing the level of COX by 0.070 ± 0.019 OD and 0.062 ± 0.019 OD, respectively. These effects were not species specific, as Langendorff-perfused mouse hearts treated with adenosine demonstrated similar changes. These data are consistent with paradoxical arteriole constriction as a major source of regional anoxia during saline heart perfusion. We suggest that the vasoregulatory network is disrupted by the washout of interstitial vasoactive metabolites in vitro. NEW & NOTEWORTHY Regional tissue anoxia is a common finding in the ubiquitous saline-perfused heart but is not found in vivo. Noninvasive optical techniques confirmed the presence of regional anoxia under control conditions and demonstrated that anoxia is diminished using exogenous vasodilators. These data are consistent with active arteriole constriction, occurring despite regional anoxia, generated by a disrupted vasoregulatory network. Washout of interstitial vasoactive metabolites may contribute to the disruption of normal vasoregulatory processes in vitro.
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Affiliation(s)
- Abigail V Giles
- Laboratory of Cardiac Energetics, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Junhui Sun
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Armel N Femnou
- Laboratory of Cardiac Energetics, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Sarah Kuzmiak-Glancy
- Department of Kinesiology, School of Public Health, University of Maryland , College Park, Maryland
| | - Joni L Taylor
- Division of Veterinary Resources, National Institutes of Health , Bethesda, Maryland
| | - Raul Covian
- Laboratory of Cardiac Energetics, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Elizabeth Murphy
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Robert S Balaban
- Laboratory of Cardiac Energetics, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
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Xiong Y, Xiong Y, Wang Y, Zhao Y, Li Y, Ren Y, Wang R, Zhao M, Hao Y, Liu H, Wang X. Exhaustive-exercise-induced oxidative stress alteration of erythrocyte oxygen release capacity. Can J Physiol Pharmacol 2018; 96:953-962. [DOI: 10.1139/cjpp-2017-0691] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The aim of the present study was to explore the effect of exhaustive running exercise in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control, moderate running exercise, and exhaustive running exercise groups. The thermodynamic and kinetic properties of the erythrocyte oxygen release process of the different groups were tested. We also determined the degree of band-3 oxidation and phosphorylation, anion transport activity, and carbonic anhydrase isoform II activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in thiobarbituric acid reactive substances and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamic and kinetic properties of RBC oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive-running-induced alterations in erythrocyte oxygen release thermodynamic and kinetic properties.
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Affiliation(s)
- Yanlian Xiong
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Yanlei Xiong
- Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS), School of Basic Medicine, Peking Union Medical College, Beijing (PUMC), P.R. China
| | - Yueming Wang
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Yajin Zhao
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Yaojin Li
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Yang Ren
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Ruofeng Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Mingzi Zhao
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Yitong Hao
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Haibei Liu
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Xiang Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
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Kalsi KK, Chiesa ST, Trangmar SJ, Ali L, Lotlikar MD, González-Alonso J. Mechanisms for the control of local tissue blood flow during thermal interventions: influence of temperature-dependent ATP release from human blood and endothelial cells. Exp Physiol 2018; 102:228-244. [PMID: 27859767 PMCID: PMC5363389 DOI: 10.1113/ep085910] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/14/2016] [Indexed: 12/17/2022]
Abstract
New Findings What is the central question of this study? Skin and muscle blood flow increases with heating and decreases with cooling, but the temperature‐sensitive mechanisms underlying these responses are not fully elucidated. What is the main finding and its importance? We found that local tissue hyperaemia was related to elevations in ATP release from erythrocytes. Increasing intravascular ATP augmented skin and tissue perfusion to levels equal or above thermal hyperaemia. ATP release from isolated erythrocytes was altered by heating and cooling. Our findings suggest that erythrocytes are involved in thermal regulation of blood flow via modulation of ATP release.
Local tissue perfusion changes with alterations in temperature during heating and cooling, but the thermosensitivity of the vascular ATP signalling mechanisms for control of blood flow during thermal interventions remains unknown. Here, we tested the hypotheses that the release of the vasodilator mediator ATP from human erythrocytes, but not from endothelial cells or other blood constituents, is sensitive to both increases and reductions in temperature and that increasing intravascular ATP availability with ATP infusion would potentiate thermal hyperaemia in limb tissues. We first measured blood temperature, brachial artery blood flow and plasma [ATP] during passive arm heating and cooling in healthy men and found that they increased by 3.0 ± 1.2°C, 105 ± 25 ml min−1 °C−1 and twofold, respectively, (all P < 0.05) with heating, but decreased or remained unchanged with cooling. In additional men, infusion of ATP into the brachial artery increased skin and deep tissue perfusion to levels equal or above thermal hyperaemia. In isolated erythrocyte samples exposed to different temperatures, ATP release increased 1.9‐fold from 33 to 39°C (P < 0.05) and declined by ∼50% at 20°C (P < 0.05), but no changes were observed in cultured human endothelial cells, plasma or serum samples. In conclusion, increases in plasma [ATP] and skin and deep tissue perfusion with limb heating are associated with elevations in ATP release from erythrocytes, but not from endothelial cells or other blood constituents. Erythrocyte ATP release is also sensitive to temperature reductions, suggesting that erythrocytes may function as thermal sensors and ATP signalling generators for control of tissue perfusion during thermal interventions.
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Affiliation(s)
- Kameljit K Kalsi
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Scott T Chiesa
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Steven J Trangmar
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Leena Ali
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK.,Department of Anaesthetics, Ealing Hospital NHS Trust, Southall, UK
| | - Makrand D Lotlikar
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK.,Department of Anaesthetics, Ealing Hospital NHS Trust, Southall, UK
| | - José González-Alonso
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
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28
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The Effect of Sepsis on the Erythrocyte. Int J Mol Sci 2017; 18:ijms18091932. [PMID: 28885563 PMCID: PMC5618581 DOI: 10.3390/ijms18091932] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/31/2017] [Accepted: 09/04/2017] [Indexed: 12/25/2022] Open
Abstract
Sepsis induces a wide range of effects on the red blood cell (RBC). Some of the effects including altered metabolism and decreased 2,3-bisphosphoglycerate are preventable with appropriate treatment, whereas others, including decreased erythrocyte deformability and redistribution of membrane phospholipids, appear to be permanent, and factors in RBC clearance. Here, we review the effects of sepsis on the erythrocyte, including changes in RBC volume, metabolism and hemoglobin's affinity for oxygen, morphology, RBC deformability (an early indicator of sepsis), antioxidant status, intracellular Ca2+ homeostasis, membrane proteins, membrane phospholipid redistribution, clearance and RBC O₂-dependent adenosine triphosphate efflux (an RBC hypoxia signaling mechanism involved in microvascular autoregulation). We also consider the causes of these effects by host mediated oxidant stress and bacterial virulence factors. Additionally, we consider the altered erythrocyte microenvironment due to sepsis induced microvascular dysregulation and speculate on the possible effects of RBC autoxidation. In future, a better understanding of the mechanisms involved in sepsis induced erythrocyte pathophysiology and clearance may guide improved sepsis treatments. Evidence that small molecule antioxidants protect the erythrocyte from loss of deformability, and more importantly improve septic patient outcome suggest further research in this area is warranted. While not generally considered a critical factor in sepsis, erythrocytes (and especially a smaller subpopulation) appear to be highly susceptible to sepsis induced injury, provide an early warning signal of sepsis and are a factor in the microvascular dysfunction that has been associated with organ dysfunction.
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Sové RJ, Fraser GM, Goldman D, Ellis CG. Finite Element Model of Oxygen Transport for the Design of Geometrically Complex Microfluidic Devices Used in Biological Studies. PLoS One 2016; 11:e0166289. [PMID: 27829071 PMCID: PMC5102494 DOI: 10.1371/journal.pone.0166289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/26/2016] [Indexed: 01/09/2023] Open
Abstract
Red blood cells play a crucial role in the local regulation of oxygen supply in the microcirculation through the oxygen dependent release of ATP. Since red blood cells serve as an oxygen sensor for the circulatory system, the dynamics of ATP release determine the effectiveness of red blood cells to relate the oxygen levels to the vessels. Previous work has focused on the feasibility of developing a microfluidic system to measure the dynamics of ATP release. The objective was to determine if a steep oxygen gradient could be developed in the channel to cause a rapid decrease in hemoglobin oxygen saturation in order to measure the corresponding levels of ATP released from the red blood cells. In the present study, oxygen transport simulations were used to optimize the geometric design parameters for a similar system which is easier to fabricate. The system is composed of a microfluidic device stacked on top of a large, gas impermeable flow channel with a hole to allow gas exchange. The microfluidic device is fabricated using soft lithography in polydimethyl-siloxane, an oxygen permeable material. Our objective is twofold: (1) optimize the parameters of our system and (2) develop a method to assess the oxygen distribution in complex 3D microfluidic device geometries. 3D simulations of oxygen transport were performed to simulate oxygen distribution throughout the device. The simulations demonstrate that microfluidic device geometry plays a critical role in molecule exchange, for instance, changing the orientation of the short wide microfluidic channel results in a 97.17% increase in oxygen exchange. Since microfluidic devices have become a more prominent tool in biological studies, understanding the transport of oxygen and other biological molecules in microfluidic devices is critical for maintaining a physiologically relevant environment. We have also demonstrated a method to assess oxygen levels in geometrically complex microfluidic devices.
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Affiliation(s)
- Richard J. Sové
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Graham M. Fraser
- Department of Medical Biophysics, Western University, London, Ontario, Canada
- Cardiovascular Research Group, Division of BioMedical Sciences, Faculty of Medicine, Memorial University, St. John’s, Newfoundland, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, Western University, London, Ontario, Canada
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Short-Term Effects of Chlorpromazine on Oxidative Stress in Erythrocyte Functionality: Activation of Metabolism and Membrane Perturbation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:2394130. [PMID: 27579150 PMCID: PMC4992801 DOI: 10.1155/2016/2394130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/05/2016] [Accepted: 07/14/2016] [Indexed: 11/17/2022]
Abstract
The purpose of this paper is to focus on the short-term effects of chlorpromazine on erythrocytes because it is reported that the drug, unstable in plasma but more stable in erythrocytes, interacts with erythrocyte membranes, membrane lipids, and hemoglobin. There is a rich literature about the side and therapeutic effects or complications due to chlorpromazine, but most of these studies explore the influence of long-term treatment. We think that evaluating the short-term effects of the drug may help to clarify the sequence of chlorpromazine molecular targets from which some long-term effects derive. Our results indicate that although the drug is primarily intercalated in the innermost side of the membrane, it does not influence band 3 anionic flux, lipid peroxidation, and protein carbonylation processes. On the other hand, it destabilizes and increases the autooxidation of haemoglobin, induces activation of caspase 3, and, markedly, influences the ATP and reduced glutathione levels, with subsequent exposure of phosphatidylserine at the erythrocyte surface. Overall our observations on the early stage of chlorpromazine influence on erythrocytes may contribute to better understanding of new and interesting characteristics of this compound improving knowledge of erythrocyte metabolism.
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31
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Miranda M, Balarini M, Caixeta D, Bouskela E. Microcirculatory dysfunction in sepsis: pathophysiology, clinical monitoring, and potential therapies. Am J Physiol Heart Circ Physiol 2016; 311:H24-35. [DOI: 10.1152/ajpheart.00034.2016] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 04/20/2016] [Indexed: 02/06/2023]
Abstract
Abnormal microvascular perfusion, including decreased functional capillary density and increased blood flow heterogeneity, is observed in early stages of the systemic inflammatory response to infection and appears to have prognostic significance in human sepsis. It is known that improvements in systemic hemodynamics are weakly correlated with the correction of microcirculatory parameters, despite an appropriate treatment of macrohemodynamic abnormalities. Furthermore, conventional hemodynamic monitoring systems available in clinical practice fail to detect microcirculatory parameter changes and responses to treatments, as they do not evaluate intrinsic events that occur in the microcirculation. Fortunately, some bedside diagnostic methods and therapeutic options are specifically directed to the assessment and treatment of microcirculatory changes. In the present review we discuss fundamental aspects of septic microcirculatory abnormalities, including pathophysiology, clinical monitoring, and potential therapies.
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Affiliation(s)
- Marcos Miranda
- Laboratory for Clinical and Experimental Research in Vascular Biology, BioVasc, Biomedical Center, Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil
| | - Michelle Balarini
- Internal Medicine Department, Andaraí Federal Hospital, Rio de Janeiro, RJ, Brazil; and
| | | | - Eliete Bouskela
- Laboratory for Clinical and Experimental Research in Vascular Biology, BioVasc, Biomedical Center, Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil
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32
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Al-Khazraji BK, Saleem A, Goldman D, Jackson DN. From one generation to the next: a comprehensive account of sympathetic receptor control in branching arteriolar trees. J Physiol 2016; 593:3093-108. [PMID: 25952132 DOI: 10.1113/jp270490] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/22/2015] [Indexed: 12/14/2022] Open
Abstract
The effect of the sympathetic nervous system on blood flow distribution within skeletal muscle microvasculature is conditional upon regional activation of receptors for sympathetic neurotransmitters. Previous studies have shown that proximal arterioles are largely governed by adrenergic activation, whereas it is speculated that distal branches are controlled by peptidergic and purinergic activation. However, no study has systematically evaluated the activation of adrenergic, peptidergic and purinergic receptors in continuously branching arteriolar trees of an individual skeletal muscle model. Therefore, in the present study, sympathetic agonists were used to evaluate the constriction responses along first to fifth order arterioles in continuously branching arteriolar trees of a in vivo rat gluteus maximus muscle preparation with respect to specific activation of receptors for sympathetic neurotransmitters (α1R, α2R, NPY1R and P2X1R). Constriction responses were incorporated into a mathematical blood flow model to estimate the total flow, resistance and red blood cell flow heterogeneity within a computationally reconstructed gluteus maximus arteriolar network. For the first time, the effects of activating receptors for sympathetic neurotransmitters on vasoconstrictor responses and the ensuing haemodynamics in continuously branching arteriolar trees of skeletal muscle were characterized, where proximal arterioles responded most to α1R and α2R adrenergic activation, whereas distal arterioles responded most to Y1R and P2X1R activation. Total flow and resistance changed with activation of all receptors, whereas red blood cell flow heterogeneity was largely affected by peptidergic and purinergic activation in distal arterioles. The reported data highlight the functional consequences of topologically-dependent sympathetic control and may serve as novel input parameters in computational modelling of network flow.
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Affiliation(s)
- Baraa K Al-Khazraji
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Amani Saleem
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.,Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario, Canada
| | - Dwayne N Jackson
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.,Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario, Canada
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33
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Ainslie PN, Hoiland RL, Bailey DM. Lessons from the laboratory; integrated regulation of cerebral blood flow during hypoxia. Exp Physiol 2016; 101:1160-1166. [PMID: 27058994 DOI: 10.1113/ep085671] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/30/2016] [Indexed: 11/08/2022]
Abstract
What is the topic of this review? What is the mechanism underlying the control of human cerebral blood flow in hypoxia and what are the consequences? What advances does it highlight? Although appropriate elevations in cerebral blood flow occur in acute and chronic hypoxia, neuronal processes are more sensitive to even small hypoxic insults; hence, they can result in maladaptive consequences despite maintenance of global oxygen delivery. Exposure to acute or chronic hypoxaemia in otherwise healthy humans results in compensatory increases in cerebral blood flow (CBF) at rest and during exercise, referred to as hypoxic cerebral vasodilatation. These elevations in CBF offset the reduction in arterial oxygen content and maintain cerebral O2 delivery, conforming to the conservation of mass principle. In this review, we discuss the fundamental principles that contribute to the defence of cerebral O2 delivery and the corresponding implications for metabolism. We critically address to what extent the increase in CBF reflects an adaptive or indeed maladaptive physiological response. The molecular mechanisms of CBF regulation in hypoxia are also briefly discussed and future directions proposed.
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Affiliation(s)
- Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada.,Neurovascular Research Laboratory, Research Institute of Health and Wellbeing, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Damian M Bailey
- Neurovascular Research Laboratory, Research Institute of Health and Wellbeing, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK
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34
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Ellsworth ML, Ellis CG, Sprague RS. Role of erythrocyte-released ATP in the regulation of microvascular oxygen supply in skeletal muscle. Acta Physiol (Oxf) 2016; 216:265-76. [PMID: 26336065 DOI: 10.1111/apha.12596] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 05/18/2015] [Accepted: 08/28/2015] [Indexed: 12/23/2022]
Abstract
In a 1914 book entitled The Respiratory Function of the Blood, Joseph Barcroft stated that 'the cell takes what it needs and leaves the rest'. He postulated that there must be both a 'call for oxygen' and a 'mechanism by which the call elicits a response...' In the past century, intensive investigation has provided significant insights into the haemodynamic and biophysical mechanisms involved in supplying oxygen to skeletal muscle. However, the identification of the mechanism by which tissue oxygen needs are sensed and the affector responsible for altering the upstream vasculature to enable the need to be appropriately met has been a challenge. In 1995, Ellsworth et al. proposed that the oxygen-carrying erythrocyte, by virtue of its capacity to release the vasoactive mediator ATP in response to a decrease in oxygen saturation, could serve both roles. Several in vitro and in situ studies have established that exposure of erythrocytes to reduced oxygen tension induces the release of ATP which does result in a conducted arteriolar vasodilation with a sufficiently rapid time course to make the mechanism physiologically relevant. The components of the signalling pathway for the controlled release of ATP from erythrocytes in response to exposure to low oxygen tension have been determined. In addition, the implications of defective ATP release on human pathological conditions have been explored. This review provides a perspective on oxygen supply and the role that such a mechanism plays in meeting the oxygen needs of skeletal muscle.
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Affiliation(s)
- M. L. Ellsworth
- Department of Pharmacological and Physiological Science; Saint Louis University School of Medicine; St. Louis MO USA
| | - C. G. Ellis
- Departments of Medical Biophysics and Medicine; Schulich School of Medicine & Dentistry; The University of Western Ontario; London ON Canada
| | - R. S. Sprague
- Department of Pharmacological and Physiological Science; Saint Louis University School of Medicine; St. Louis MO USA
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35
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Carelli-Alinovi C, Ficarra S, Russo AM, Giunta E, Barreca D, Galtieri A, Misiti F, Tellone E. Involvement of acetylcholinesterase and protein kinase C in the protective effect of caffeine against β-amyloid-induced alterations in red blood cells. Biochimie 2016; 121:52-9. [DOI: 10.1016/j.biochi.2015.11.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 11/22/2015] [Indexed: 02/04/2023]
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36
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Hoiland RL, Bain AR, Rieger MG, Bailey DM, Ainslie PN. Hypoxemia, oxygen content, and the regulation of cerebral blood flow. Am J Physiol Regul Integr Comp Physiol 2015; 310:R398-413. [PMID: 26676248 DOI: 10.1152/ajpregu.00270.2015] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/30/2015] [Indexed: 01/13/2023]
Abstract
This review highlights the influence of oxygen (O2) availability on cerebral blood flow (CBF). Evidence for reductions in O2 content (CaO2 ) rather than arterial O2 tension (PaO2 ) as the chief regulator of cerebral vasodilation, with deoxyhemoglobin as the primary O2 sensor and upstream response effector, is discussed. We review in vitro and in vivo data to summarize the molecular mechanisms underpinning CBF responses during changes in CaO2 . We surmise that 1) during hypoxemic hypoxia in healthy humans (e.g., conditions of acute and chronic exposure to normobaric and hypobaric hypoxia), elevations in CBF compensate for reductions in CaO2 and thus maintain cerebral O2 delivery; 2) evidence from studies implementing iso- and hypervolumic hemodilution, anemia, and polycythemia indicate that CaO2 has an independent influence on CBF; however, the increase in CBF does not fully compensate for the lower CaO2 during hemodilution, and delivery is reduced; and 3) the mechanisms underpinning CBF regulation during changes in O2 content are multifactorial, involving deoxyhemoglobin-mediated release of nitric oxide metabolites and ATP, deoxyhemoglobin nitrite reductase activity, and the downstream interplay of several vasoactive factors including adenosine and epoxyeicosatrienoic acids. The emerging picture supports the role of deoxyhemoglobin (associated with changes in CaO2 ) as the primary biological regulator of CBF. The mechanisms for vasodilation therefore appear more robust during hypoxemic hypoxia than during changes in CaO2 via hemodilution. Clinical implications (e.g., disorders associated with anemia and polycythemia) and future study directions are considered.
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Affiliation(s)
- Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada; and
| | - Anthony R Bain
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada; and
| | - Mathew G Rieger
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada; and
| | - Damian M Bailey
- Neurovascular Research Laboratory, Research Institute of Science and Health, University of South Wales, Glamorgan, United Kingdom
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada; and Neurovascular Research Laboratory, Research Institute of Science and Health, University of South Wales, Glamorgan, United Kingdom
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37
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Burnstock G. Blood cells: an historical account of the roles of purinergic signalling. Purinergic Signal 2015; 11:411-34. [PMID: 26260710 PMCID: PMC4648797 DOI: 10.1007/s11302-015-9462-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 07/23/2015] [Indexed: 12/17/2022] Open
Abstract
The involvement of purinergic signalling in the physiology of erythrocytes, platelets and leukocytes was recognised early. The release of ATP and the expression of purinoceptors and ectonucleotidases on erythrocytes in health and disease are reviewed. The release of ATP and ADP from platelets and the expression and roles of P1, P2Y(1), P2Y(12) and P2X1 receptors on platelets are described. P2Y(1) and P2X(1) receptors mediate changes in platelet shape, while P2Y(12) receptors mediate platelet aggregation. The changes in the role of purinergic signalling in a variety of disease conditions are considered. The successful use of P2Y(12) receptor antagonists, such as clopidogrel and ticagrelor, for the treatment of thrombosis, myocardial infarction and stroke is discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK.
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Australia.
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38
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Yipintsoi T, Kroll K, Bassingthwaighte JB. Fractal regional myocardial blood flows pattern according to metabolism, not vascular anatomy. Am J Physiol Heart Circ Physiol 2015; 310:H351-64. [PMID: 26589329 DOI: 10.1152/ajpheart.00632.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/02/2015] [Indexed: 11/22/2022]
Abstract
Regional myocardial blood flows are markedly heterogeneous. Fractal analysis shows strong near-neighbor correlation. In experiments to distinguish control by vascular anatomy vs. local vasomotion, coronary flows were increased in open-chest dogs by stimulating myocardial metabolism (catecholamines + atropine) with and without adenosine. During control states mean left ventricular (LV) myocardial blood flows (microspheres) were 0.5-1 ml·g(-1)·min(-1) and increased to 2-3 ml·g(-1)·min(-1) with catecholamine infusion and to ∼4 ml·g(-1)·min(-1) with adenosine (Ado). Flow heterogeneity was similar in all states: relative dispersion (RD = SD/mean) was ∼25%, using LV pieces 0.1-0.2% of total. During catecholamine infusion local flows increased in proportion to the mean flows in 45% of the LV, "tracking" closely (increased proportionately to mean flow), while ∼40% trended toward the mean. Near-neighbor regional flows remained strongly spatially correlated, with fractal dimension D near 1.2 (Hurst coefficient 0.8). The spatial patterns remain similar at varied levels of metabolic stimulation inferring metabolic dominance. In contrast, adenosine vasodilation increased flows eightfold times control while destroying correlation with the control state. The Ado-induced spatial patterns differed from control but were self-consistent, inferring that with full vasodilation the relaxed arterial anatomy dominates the distribution. We conclude that vascular anatomy governs flow distributions during adenosine vasodilation but that metabolic vasoregulation dominates in normal physiological states.
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Affiliation(s)
- Tada Yipintsoi
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Keith Kroll
- Department of Bioengineering, University of Washington, Seattle, Washington
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39
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Nyberg M, Gliemann L, Hellsten Y. Vascular function in health, hypertension, and diabetes: effect of physical activity on skeletal muscle microcirculation. Scand J Med Sci Sports 2015; 25 Suppl 4:60-73. [DOI: 10.1111/sms.12591] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2015] [Indexed: 12/31/2022]
Affiliation(s)
- M. Nyberg
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
| | - L. Gliemann
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
| | - Y. Hellsten
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
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Bateman RM, Sharpe MD, Jagger JE, Ellis CG. Sepsis impairs microvascular autoregulation and delays capillary response within hypoxic capillaries. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2015; 19:389. [PMID: 26537126 PMCID: PMC4634189 DOI: 10.1186/s13054-015-1102-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/16/2015] [Indexed: 11/10/2022]
Abstract
Introduction The microcirculation supplies oxygen (O2) and nutrients to all cells with the red blood cell (RBC) acting as both a deliverer and sensor of O2. In sepsis, a proinflammatory disease with microvascular complications, small blood vessel alterations are associated with multi-organ dysfunction and poor septic patient outcome. We hypothesized that microvascular autoregulation—existing at three levels: over the entire capillary network, within a capillary and within the erythrocyte—was impaired during onset of sepsis. This study had three objectives: 1) measure capillary response time within hypoxic capillaries, 2) test the null hypothesis that RBC O2-dependent adenosine triphosphate (ATP) efflux was not altered by sepsis and 3) develop a framework of a pathophysiological model. Methods This was an animal study, comparing sepsis with control, set in a university laboratory. Acute hypotensive sepsis was studied using cecal ligation and perforation (CLP) with a 6-hour end-point. Rat hindlimb skeletal muscle microcirculation was imaged, and capillary RBC supply rate (SR = RBC/s), RBC hemoglobin O2 saturation (SO2) and O2 supply rate (qO2 = pLO2/s) were quantified. Arterial NOx (nitrite + nitrate) and RBC O2-dependent ATP efflux were measured using a nitric oxide (NO) analyzer and gas exchanger, respectively. Results Sepsis increased capillary stopped-flow (p = 0.001) and increased plasma lactate (p < 0.001). Increased plasma NOx (p < 0.001) was related to increased capillary RBC supply rate (p = 0.027). Analysis of 30-second SR–SO2–qO2 profiles revealed a shift towards decreased (p < 0.05) O2 supply rates in some capillaries. Moreover, we detected a three- to fourfold increase (p < 0.05) in capillary response time within hypoxic capillaries (capillary flow states where RBC SO2 < 20 %). Additionally, sepsis decreased the erythrocyte’s ability to respond to hypoxic environments, as normalized RBC O2-dependent ATP efflux decreased by 62.5 % (p < 0.001). Conclusions Sepsis impaired microvascular autoregulation at both the individual capillary and erythrocyte level, seemingly uncoupling the RBC acting as an “O2 sensor” from microvascular autoregulation. Impaired microvascular autoregulation was manifested by increased capillary stopped-flow, increased capillary response time within hypoxic capillaries, decreased capillary O2 supply rate and decreased RBC O2-dependent ATP efflux. This loss of local microvascular control was partially off-set by increased capillary RBC supply rate, which correlated with increased plasma NOx. Electronic supplementary material The online version of this article (doi:10.1186/s13054-015-1102-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ryon M Bateman
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada. .,Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan. .,Ryleeon, 18519-77 Ave NW, Edmonton, AB, T5T6A8, Canada.
| | - Michael D Sharpe
- Department of Anesthesia and Critical Care Western, University of Western Ontario, London, ON, Canada.
| | - Justin E Jagger
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada.
| | - Christopher G Ellis
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada.
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41
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Luo GY, Sun L, Wei EX, Tan X, Liu TCY. The effects of low-intensity He-Ne laser irradiation on erythrocyte metabolism. Lasers Med Sci 2015; 30:2313-8. [PMID: 26407713 DOI: 10.1007/s10103-015-1806-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/10/2015] [Indexed: 10/23/2022]
Abstract
Low-intensity laser irradiation (LILI) can improve the deformability of red blood cells (RBCs). It might be due to the LILI effects on adenosine triphosphate (ATP) level. However, ATP content may not be a valid surrogate marker for RBC deformability. The LILI effects on RBC glycolysis were studied in this paper. Hypertonic RBCs were used in this study. After 5 min irradiation with low-intensity He-Ne laser irradiation (LHNL) at 632.8 nm and 4.4 mW/cm(2), the concentration of intracellular glucose and the activities of phosphofructokinase (PFK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were measured, respectively. There was no significant change in intracellular glucose concentration. The activity of PFK decreased significantly, but the activity of GAPDH increased significantly. In hypertonic RBCs, LHNL irradiation may decrease the activity of energy-consuming enzymes, but increases the activity of energy-generating enzymes in glycolysis, to improve the RBC deformability.
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Affiliation(s)
- Gang-Yue Luo
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Li Sun
- Medical College, Jinan University, Guangzhou, 510632, China
| | - En-Xiu Wei
- Laboratory of Laser Sports Medicine, South China Normal University, University Town, Guangzhou, 510006, China
| | - Xiaodong Tan
- Department of Otolaryngology, Northwestern University, Chicago, IL, 60611, USA
| | - Timon Cheng-Yi Liu
- Laboratory of Laser Sports Medicine, South China Normal University, University Town, Guangzhou, 510006, China.
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42
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González-Alonso J, Calbet JAL, Boushel R, Helge JW, Søndergaard H, Munch-Andersen T, van Hall G, Mortensen SP, Secher NH. Blood temperature and perfusion to exercising and non-exercising human limbs. Exp Physiol 2015; 100:1118-31. [PMID: 26268717 PMCID: PMC5049637 DOI: 10.1113/ep085383] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/07/2015] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? Temperature-sensitive mechanisms are thought to contribute to blood-flow regulation, but the relationship between exercising and non-exercising limb perfusion and blood temperature is not established. What is the main finding and its importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non-exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature- and metabolism-sensitive mechanisms are important for the control of human limb perfusion, possibly by activating ATP release from the erythrocytes. Temperature-sensitive mechanisms may contribute to blood-flow regulation, but the influence of temperature on perfusion to exercising and non-exercising human limbs is not established. Blood temperature (TB ), blood flow and oxygen uptake (V̇O2) in the legs and arms were measured in 16 healthy humans during 90 min of leg and arm exercise and during exhaustive incremental leg or arm exercise. During prolonged exercise, leg blood flow (LBF) was fourfold higher than arm blood flow (ABF) in association with higher TB and limb V̇O2. Leg and arm vascular conductance during exercise compared with rest was related closely to TB (r(2) = 0.91; P < 0.05), plasma ATP (r(2) = 0.94; P < 0.05) and limb V̇O2 (r(2) = 0.99; P < 0.05). During incremental leg exercise, LBF increased in association with elevations in TB and limb V̇O2, whereas ABF, arm TB and V̇O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V̇O2. In 12 trained males, increases in femoral TB and LBF during incremental leg exercise were mirrored by similar pulmonary artery TB and cardiac output dynamics, suggesting that processes in active limbs dominate central temperature and perfusion responses. The present data reveal a close coupling among perfusion, TB and aerobic metabolism in exercising and non-exercising extremities and a tight association between limb vasodilatation and increases in plasma ATP. These findings suggest that temperature and V̇O2 contribute to the regulation of limb perfusion through control of intravascular ATP.
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Affiliation(s)
- José González-Alonso
- Centre for Sports Medicine and Human Performance, Brunel University London, Uxbridge, UK.,The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - José A L Calbet
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Physical Education, and Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Robert Boushel
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Jørn W Helge
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Centre for Healthy Ageing, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Søndergaard
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Thor Munch-Andersen
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Gerrit van Hall
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Stefan P Mortensen
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Niels H Secher
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Denmark
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44
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Wolff G, Truse R, Decking U. Extracellular Adenosine Formation by Ecto-5'-Nucleotidase (CD73) Is No Essential Trigger for Early Phase Ischemic Preconditioning. PLoS One 2015; 10:e0135086. [PMID: 26261991 PMCID: PMC4532361 DOI: 10.1371/journal.pone.0135086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/16/2015] [Indexed: 11/20/2022] Open
Abstract
Background Adenosine is a powerful trigger for ischemic preconditioning (IPC). Myocardial ischemia induces intracellular and extracellular ATP degradation to adenosine, which then activates adenosine receptors and elicits cardioprotection. Conventionally extracellular adenosine formation by ecto-5’-nucleotidase (CD73) during ischemia was thought to be negligible compared to the massive intracellular production, but controversial reports in the past demand further evaluation. In this study we evaluated the relevance of ecto-5’-nucleotidase (CD73) for infarct size reduction by ischemic preconditioning in in vitro and in vivo mouse models of myocardial infarction, comparing CD73-/- and wild type (WT) mice. Methods and Results 3x5 minutes of IPC induced equal cardioprotection in isolated saline perfused hearts of wild type (WT) and CD73-/- mice, reducing control infarct sizes after 20 minutes of ischemia and 90 minutes of reperfusion from 46 ± 6.3% (WT) and 56.1 ± 7.6% (CD73-/-) to 26.8 ± 4.7% (WT) and 25.6 ± 4.7% (CD73-/-). Coronary venous adenosine levels measured after IPC stimuli by high-pressure liquid chromatography showed no differences between WT and CD73-/- hearts. Pharmacological preconditioning of WT hearts with adenosine, given at the measured venous concentration, was evenly cardioprotective as conventional IPC. In vivo, 4x5 minutes of IPC reduced control infarct sizes of 45.3 ± 8.9% (WT) and 40.5 ± 8% (CD73-/-) to 26.3 ± 8% (WT) and 22.6 ± 6.6% (CD73-/-) respectively, eliciting again equal cardioprotection. The extent of IPC-induced cardioprotection in male and female mice was identical. Conclusion The infarct size limiting effects of IPC in the mouse heart in vitro and in vivo are not significantly affected by genetic inactivation of CD73. The ecto-5’-nucleotidase derived extracellular formation of adenosine does not contribute substantially to adenosine’s well known cardioprotective effect in early phase ischemic preconditioning.
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Affiliation(s)
- Georg Wolff
- Department of Cardiovascular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- * E-mail:
| | - Richard Truse
- Department of Cardiovascular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Ulrich Decking
- Department of Cardiovascular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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45
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Crecelius AR, Kirby BS, Dinenno FA. Intravascular ATP and the regulation of blood flow and oxygen delivery in humans. Exerc Sport Sci Rev 2015; 43:5-13. [PMID: 25390296 DOI: 10.1249/jes.0000000000000031] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Regulation of vascular tone is a complex response that integrates multiple signals that allow for blood flow and oxygen supply to match oxygen demand appropriately. Here, we discuss the potential role of intravascular adenosine triphosphate (ATP) as a primary factor in these responses and put forth the hypothesis that deficient ATP release contributes to impairments in vascular control exhibited in aged and diseased populations.
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Affiliation(s)
- Anne R Crecelius
- 1Department Health and Sport Science, University of Dayton, Dayton, OH; 2Digital Sport Science Laboratory, Nike Inc., Beaverton, OR; and 3Departments of Health and Exercise Science, and 4Biomedical Sciences, Colorado State University, Fort Collins, CO
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46
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Joyner MJ, Casey DP. Regulation of increased blood flow (hyperemia) to muscles during exercise: a hierarchy of competing physiological needs. Physiol Rev 2015; 95:549-601. [PMID: 25834232 DOI: 10.1152/physrev.00035.2013] [Citation(s) in RCA: 422] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans.
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Affiliation(s)
- Michael J Joyner
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
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Abstract
PURPOSE OF REVIEW Oxygen (O2) delivery, the maintenance of which is fundamental to supporting those with critical illness, is a function of blood O2 content and flow. Here, we review red blood cell (RBC) physiology relevant to disordered O2 delivery in the critically ill. RECENT FINDINGS Flow (rather than content) is the focus of O2 delivery regulation. O2 content is relatively fixed, whereas flow fluctuates by several orders of magnitude. Thus, blood flow volume and distribution vary to maintain coupling between O2 delivery and demand. The trapping, processing and delivery of nitric oxide (NO) by RBCs has emerged as a conserved mechanism through which regional blood flow is linked to biochemical cues of perfusion sufficiency. We will review conventional RBC physiology that influences O2 delivery (O2 affinity & rheology) and introduce a new paradigm for O2 delivery homeostasis based on coordinated gas transport and vascular signaling by RBCs. SUMMARY By coordinating vascular signaling in a fashion that links O2 and NO flux, RBCs couple vessel caliber (and thus blood flow) to O2 need in tissue. Malfunction of this signaling system is implicated in a wide array of pathophysiologies and may be explanatory for the dysoxia frequently encountered in the critical care setting.
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48
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Dinenno FA. Skeletal muscle vasodilation during systemic hypoxia in humans. J Appl Physiol (1985) 2015; 120:216-25. [PMID: 26023228 DOI: 10.1152/japplphysiol.00256.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/21/2015] [Indexed: 11/22/2022] Open
Abstract
In humans, the net effect of acute systemic hypoxia in quiescent skeletal muscle is vasodilation despite significant reflex increases in muscle sympathetic vasoconstrictor nerve activity. This vasodilation increases tissue perfusion and oxygen delivery to maintain tissue oxygen consumption. Although several mechanisms may be involved, we recently tested the roles of two endothelial-derived substances during conditions of sympathoadrenal blockade to isolate local vascular control mechanisms: nitric oxide (NO) and prostaglandins (PGs). Our findings indicate that 1) NO normally plays a role in regulating vascular tone during hypoxia independent of the PG pathway; 2) PGs do not normally contribute to vascular tone during hypoxia, however, they do affect vascular tone when NO is inhibited; 3) NO and PGs are not independently obligatory to observe hypoxic vasodilation when assessed as a response from rest to steady-state hypoxia; and 4) combined NO and PG inhibition abolishes hypoxic vasodilation in human skeletal muscle. When the stimulus is exacerbated via combined submaximal rhythmic exercise and systemic hypoxia to cause further red blood cell (RBC) deoxygenation, skeletal muscle blood flow is augmented compared with normoxic exercise via local dilator mechanisms to maintain oxygen delivery to active tissue. Data obtained in a follow-up study indicate that combined NO and PG inhibition during hypoxic exercise blunts augmented vasodilation and hyperemia compared with control (normoxic) conditions by ∼50%; however, in contrast to hypoxia alone, the response is not abolished, suggesting that other local substances are involved. Factors associated with greater RBC deoxygenation such as ATP release, or nitrite reduction to NO, or both likely play a role in regulating this response.
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Affiliation(s)
- Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado
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Quaye IK. Extracellular hemoglobin: the case of a friend turned foe. Front Physiol 2015; 6:96. [PMID: 25941490 PMCID: PMC4403290 DOI: 10.3389/fphys.2015.00096] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/12/2015] [Indexed: 12/14/2022] Open
Abstract
Hemoglobin (Hb) is a highly conserved molecule present in all life forms and functionally tied to the complexity of aerobic organisms on earth in utilizing oxygen from the atmosphere and delivering to cells and tissues. This primary function sustains the energy requirements of cells and maintains cellular homeostasis. Decades of intensive research has presented a paradigm shift that shows how the molecule also functions to facilitate smooth oxygen delivery through the cardiovascular system for cellular bioenergetic homeostasis and signaling for cell function and defense. These roles are particularly highlighted in the binding of Hb to gaseous molecules carbon dioxide (CO2), nitric oxide (NO) and carbon monoxide (CO), while also serving indirectly or directly as sources of these signaling molecules. The functional activities impacted by Hb outside of bioenergetics homeostasis, include fertilization, signaling functions, modulation of inflammatory responses for defense and cell viability. These activities are efficiently executed while Hb is sequestered safely within the confines of the red blood cell (rbc). Outside of rbc confines, Hb disaggregates and becomes a danger molecule to cell survival. In these perpectives, Hb function is broadly dichotomous, either a friend in its natural environment providing and facilitating the means for cell function or foe when dislocated from its habitat under stress or pathological condition disrupting cell function. The review presents insights into how this dichotomy in function manifests.
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Affiliation(s)
- Isaac K Quaye
- Department of Biochemistry, University of Namibia School of Medicine Windhoek, Namibia
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Gopalakrishnan M, Saurabh S. Is red blood cell a mediator of remote ischaemic preconditioning? Med Hypotheses 2014; 83:816-8. [PMID: 25468784 DOI: 10.1016/j.mehy.2014.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 10/18/2014] [Indexed: 10/24/2022]
Abstract
Remote ischaemic preconditioning is emerging as a promising clinical technique which can afford immediate protection against coronary ischaemia. The mechanisms which mediate the signal transduction from remote organ to the heart are still unclear. The role of ATP sensitive potassium channels in ischaemic preconditioning has been established. It is known that the red blood cell (RBC) acts as a mediator of local autoregulation in adjusting oxygen supply to demand by sensing hypoxia and releasing ATP locally to achieve vasodilatation in the adjacent vascular beds. Our hypothesis links these two known mechanisms. Remote ischaemic preconditioning and local RBC autoregulation might share a common mechanism using the ATP sensitive potassium channels. Therefore, we hypothesize that the signal transduction by RBC might be partly responsible for this protection against ischaemia.
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Affiliation(s)
- Maya Gopalakrishnan
- Department of Medicine, Jawaharlal Institute of Medical Education and Research (JIPMER), Puducherry 605006, India.
| | - Suman Saurabh
- Department of Preventive and Social Medicine, Jawaharlal Institute of Medical Education and Research (JIPMER), Puducherry 605006, India
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