1
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Conde SV, Martins FO, Sacramento JF. Carotid body interoception in health and disease. Auton Neurosci 2024; 255:103207. [PMID: 39121687 DOI: 10.1016/j.autneu.2024.103207] [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: 04/24/2024] [Revised: 07/15/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024]
Abstract
Interoception entails perceiving or being aware of the internal state of the body, playing a pivotal role in regulating processes such as heartbeat, digestion, glucose metabolism, and respiration. The carotid body (CB) serves as an interoceptive organ, transmitting information to the brain via its sensitive nerve, the carotid sinus nerve, to maintain homeostasis. While traditionally known for sensing oxygen, carbon dioxide, and pH levels, the CB is now recognized to possess additional interoceptive properties, detecting various mediators involved in blood pressure regulation, inflammation, and glucose homeostasis, among other physiological functions. Furthermore, in the last decades CB dysfunction has been linked to diseases like sleep apnea, essential hypertension, and diabetes. In this review manuscript, we make a concise overview of the traditional interoceptive functions of the CB, acting as a sensor for oxygen levels, carbon dioxide levels, and pH, and introduce the novel interoceptive properties of the CB related to vascular, glucose and energy regulation. Additionally, we revise the contribution of the CB to the onset and progression of metabolic diseases, delving into the potential dysfunction of its interoceptive metabolic functions as a contributing factor to pathophysiology. Finally, we postulate the use of therapeutic interventions targeting the metabolic interoceptive properties of the CB as a potential avenue for addressing metabolic diseases.
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Affiliation(s)
- Silvia V Conde
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.
| | - Fatima O Martins
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Joana F Sacramento
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
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2
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Iturriaga R. Carotid body contribution to the physio-pathological consequences of intermittent hypoxia: role of nitro-oxidative stress and inflammation. J Physiol 2023; 601:5495-5507. [PMID: 37119020 DOI: 10.1113/jp284112] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/24/2023] [Indexed: 04/30/2023] Open
Abstract
Obstructive sleep apnoea (OSA), characterized by chronic intermittent hypoxia (CIH), is considered to be an independent risk for hypertension. The pathological cardiorespiratory consequences of OSA have been attributed to systemic oxidative stress, inflammation and sympathetic overflow induced by CIH, but an emerging body of evidence indicates that a nitro-oxidative and pro-inflammatory milieu within the carotid body (CB) is involved in the potentiation of CB chemosensory responses to hypoxia, which contribute to enhance the sympathetic activity. Accordingly, autonomic and cardiovascular alterations induced by CIH are critically dependent on an abnormally heightened CB chemosensory input to the nucleus of tractus solitarius (NTS), where second-order neurons project onto the rostral ventrolateral medulla (RVLM), activating pre-sympathetic neurons that control pre-ganglionic sympathetic neurons. CIH produces oxidative stress and neuroinflammation in the NTS and RVLM, which may contribute to the long-term irreversibility of the CIH-induced alterations. This brief review is mainly focused on the contribution of nitro-oxidative stress and pro-inflammatory molecules on the hyperactivation of the hypoxic chemoreflex pathway including the CB and the brainstem centres, and whether the persistence of autonomic and cardiorespiratory alterations may depend on the glial-related neuroinflammation induced by the enhanced CB chemosensory afferent input.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación en Fisiología y Medicina de Altura, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
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3
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Tubek S, Niewinski P, Langner-Hetmanczuk A, Jura M, Kuliczkowski W, Reczuch K, Ponikowski P. The effects of P2Y 12 adenosine receptors' inhibitors on central and peripheral chemoreflexes. Front Physiol 2023; 14:1214893. [PMID: 37538377 PMCID: PMC10394699 DOI: 10.3389/fphys.2023.1214893] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/30/2023] [Indexed: 08/05/2023] Open
Abstract
Introduction: The most common side effect of ticagrelor is dyspnea, which leads to premature withdrawal of this life-saving medication in 6.5% of patients. Increased chemoreceptors' sensitivity was suggested as a possible pathophysiological explanation of this phenomenon; however, the link between oversensitization of peripheral and/or central chemosensory areas and ticagrelor intake has not been conclusively proved. Methods: We measured peripheral chemoreceptors' sensitivity using hypoxic ventilatory response (HVR), central chemoreceptors' sensitivity using hypercapnic hyperoxic ventilatory response (HCVR), and dyspnea severity before and 4 ± 1 weeks following ticagrelor initiation in 11 subjects with chronic coronary syndrome undergoing percutaneous coronary intervention (PCI). The same tests were performed in 11 age-, sex-, and BMI-matched patients treated with clopidogrel. The study is registered at ClinicalTrials.com at NCT05080478. Results: Ticagrelor significantly increased both HVR (0.52 ± 0.46 vs. 0.84 ± 0.69 L min-1 %-1; p < 0.01) and HCVR (1.05 ± 0.64 vs. 1.75 ± 1.04 L min-1 mmHg-1; p < 0.01). The absolute change in HVR correlated with the change in HCVR. Clopidogrel administration did not significantly influence HVR (0.63 ± 0.32 vs. 0.58 ± 0.33 L min-1%-1; p = 0.53) and HCVR (1.22 ± 0.67 vs. 1.2 ± 0.64 L min-1 mmHg-1; p = 0.79). Drug-related dyspnea was reported by three subjects in the ticagrelor group and by none in the clopidogrel group. These patients were characterized by either high baseline HVR and HCVR or excessive increase in HVR following ticagrelor initiation. Discussion: Ticagrelor, contrary to clopidogrel, sensitizes both peripheral and central facets of chemodetection. Two potential mechanisms of ticagrelor-induced dyspnea have been identified: 1) high baseline HVR and HCVR or 2) excessive increase in HVR or HVR and HCVR. Whether other patterns of changes in chemosensitivities play a role in the pathogenesis of this phenomenon needs to be further investigated.
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Affiliation(s)
- Stanislaw Tubek
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Piotr Niewinski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Anna Langner-Hetmanczuk
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Maksym Jura
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
- Department of Physiology, Wroclaw Medical University, Wroclaw, Poland
| | - Wiktor Kuliczkowski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Krzysztof Reczuch
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Piotr Ponikowski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
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4
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Caballero-Eraso C, Colinas O, Sobrino V, González-Montelongo R, Cabeza JM, Gao L, Pardal R, López-Barneo J, Ortega-Sáenz P. Rearrangement of cell types in the rat carotid body neurogenic niche induced by chronic intermittent hypoxia. J Physiol 2023; 601:1017-1036. [PMID: 36647759 DOI: 10.1113/jp283897] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
The carotid body (CB) is a prototypical acute oxygen (O2 )-sensing organ that mediates reflex hyperventilation and increased cardiac output in response to hypoxaemia. CB overactivation, secondary to the repeated stimulation produced by the recurrent episodes of intermittent hypoxia, is believed to contribute to the pathogenesis of sympathetic hyperactivity present in sleep apnoea patients. Although CB functional plasticity induced by chronic intermittent hypoxia (CIH) has been demonstrated, the underlying mechanisms are not fully elucidated. Here, we show that CIH induces a small increase in CB volume and rearrangement of cell types in the CB, characterized by a mobilization of immature quiescent neuroblasts, which enter a process of differentiation into mature, O2 -sensing and neuron-like, chemoreceptor glomus cells. Prospective isolation of individual cell classes has allowed us to show that maturation of CB neuroblasts is paralleled by an upregulation in the expression of specific glomus cell genes involved in acute O2 -sensing. CIH enhances mitochondrial responsiveness to hypoxia in maturing neuroblasts as well as in glomus cells. These data provide novel perspectives on the pathogenesis of CB-mediated sympathetic overflow that may lead to the development of new pharmacological strategies of potential applicability in sleep apnoea patients. KEY POINTS: Obstructive sleep apnoea is a frequent condition in the human population that predisposes to severe cardiovascular and metabolic alterations. Activation of the carotid body, the main arterial oxygen-sensing chemoreceptor, by repeated episodes of hypoxaemia induces exacerbation of the carotid body-mediated chemoreflex and contributes to sympathetic overflow characteristic of sleep apnoea patients. In rats, chronic intermittent hypoxaemia induces fast neurogenesis in the carotid body with rapid activation of neuroblasts, which enter a process of proliferation and maturation into O2 -sensing chemoreceptor glomus cells. Maturing carotid body neuroblasts and glomus cells exposed to chronic intermittent hypoxia upregulate genes involved in acute O2 sensing and enhance mitochondrial responsiveness to hypoxia. These findings provide novel perspectives on the pathogenesis of carotid body-mediated sympathetic hyperactivation. Pharmacological modulation of carotid body fast neurogenesis could help to ameliorate the deleterious effects of chronic intermittent hypoxaemia in sleep apnoea patients.
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Affiliation(s)
- Candela Caballero-Eraso
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Unidad Médico Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocío/IBIS, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Olaia Colinas
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Verónica Sobrino
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Rafaela González-Montelongo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - José María Cabeza
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
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5
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Lazarov NE, Atanasova DY. Mechanisms of Chemosensory Transduction in the Carotid Body. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2023; 237:49-62. [PMID: 37946077 DOI: 10.1007/978-3-031-44757-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The mammalian carotid body (CB) is a polymodal chemoreceptor, which is activated by blood-borne stimuli, most notably hypoxia, hypercapnia and acidosis, thus ensuring an appropriate cellular response to changes in physical and chemical parameters of the blood. The glomus cells are considered the CB chemosensory cells and the initial site of chemoreceptor transduction. However, the molecular mechanisms by which they detect changes in blood chemical levels and how these changes lead to transmitter release are not yet well understood. Chemotransduction mechanisms are by far best described for oxygen and acid/carbon dioxide sensing. A few testable hypotheses have been postulated including a direct interaction of oxygen with ion channels in the glomus cells (membrane hypothesis), an indirect interface by a reversible ligand like a heme (metabolic hypothesis), or even a functional interaction between putative oxygen sensors (chemosome hypothesis) or the interaction of lactate with a highly expressed in the CB atypical olfactory receptor, Olfr78, (endocrine model). It is also suggested that sensory transduction in the CB is uniquely dependent on the actions and interactions of gaseous transmitters. Apparently, oxygen sensing does not utilize a single mechanism, and later observations have given strong support to a unified membrane model of chemotransduction.
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Affiliation(s)
- Nikolai E Lazarov
- Department of Anatomy and Histology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria.
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6
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Lazarov NE, Atanasova DY. Carotid Body Dysfunction and Mechanisms of Disease. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2023; 237:123-138. [PMID: 37946080 DOI: 10.1007/978-3-031-44757-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Emerging evidence shows that the carotid body (CB) dysfunction is implicated in various physiological and pathophysiological conditions. It has been revealed that the CB structure and neurochemical profile alter in certain human sympathetic-related and cardiometabolic diseases. Specifically, a tiny CB with a decrease of glomus cells and their dense-cored vesicles has been seen in subjects with sleep disordered breathing such as sudden infant death syndrome and obstructive sleep apnea patients and people with congenital central hypoventilation syndrome. Moreover, the CB degranulation is accompanied by significantly elevated levels of catecholamines and proinflammatory cytokines in such patients. The intermittent hypoxia stimulates the CB, eliciting augmented chemoreflex drive and enhanced cardiorespiratory and sympathetic responses. High CB excitability due to blood flow restrictions, oxidative stress, alterations in neurotransmitter gases and disruptions of local mediators is also observed in congestive heart failure conditions. On the other hand, the morpho-chemical changes in hypertension include an increase in the CB volume due to vasodilation, altered transmitter phenotype of chemoreceptor cells and elevated production of neurotrophic factors. Accordingly, in both humans and animal models CB denervation prevents the breathing instability and lowers blood pressure. Knowledge of the morphofunctional aspects of the CB, a better understanding of its role in disease and recent advances in human CB translational research would contribute to the development of new therapeutic strategies.
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Affiliation(s)
- Nikolai E Lazarov
- Department of Anatomy and Histology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria.
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7
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A Methodological Perspective on the Function and Assessment of Peripheral Chemoreceptors in Heart Failure: A Review of Data from Clinical Trials. Biomolecules 2022; 12:biom12121758. [PMID: 36551186 PMCID: PMC9775522 DOI: 10.3390/biom12121758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
Augmented peripheral chemoreceptor sensitivity (PChS) is a common feature of many sympathetically mediated diseases, among others, and it is an important mechanism of the pathophysiology of heart failure (HF). It is related not only to the greater severity of symptoms, especially to dyspnea and lower exercise tolerance but also to a greater prevalence of complications and poor prognosis. The causes, mechanisms, and impact of the enhanced activity of peripheral chemoreceptors (PChR) in the HF population are subject to intense research. Several methodologies have been established and utilized to assess the PChR function. Each of them presents certain advantages and limitations. Furthermore, numerous factors could influence and modulate the response from PChR in studied subjects. Nevertheless, even with the impressive number of studies conducted in this field, there are still some gaps in knowledge that require further research. We performed a review of all clinical trials in HF human patients, in which the function of PChR was evaluated. This review provides an extensive synthesis of studies evaluating PChR function in the HF human population, including methods used, factors potentially influencing the results, and predictors of increased PChS.
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8
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Gao L, Ortega-Sáenz P, Moreno-Domínguez A, López-Barneo J. Mitochondrial Redox Signaling in O 2-Sensing Chemoreceptor Cells. Antioxid Redox Signal 2022; 37:274-289. [PMID: 35044243 DOI: 10.1089/ars.2021.0255] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Significance: Acute responses to hypoxia are essential for the survival of mammals. The carotid body (CB), the main arterial chemoreceptor, contains glomus cells with oxygen (O2)-sensitive K+ channels, which are inhibited during hypoxia to trigger adaptive cardiorespiratory reflexes. Recent Advances: In this review, recent advances in molecular mechanisms of acute O2 sensing in CB glomus cells are discussed, with a special focus on the signaling role of mitochondria through regulating cellular redox status. These advances have been achieved thanks to the use of genetically engineered redox-sensitive green fluorescent protein (roGFP) probes, which allowed us to monitor rapid changes in ROS production in real time in different subcellular compartments during hypoxia. This methodology was used in combination with conditional knockout mice models, pharmacological approaches, and transcriptomic studies. We have proposed a mitochondria-to-membrane signaling model of acute O2 sensing in which H2O2 released in the mitochondrial intermembrane space serves as a signaling molecule to inhibit K+ channels on the plasma membrane. Critical Issues: Changes in mitochondrial reactive oxygen species (ROS) production during acute hypoxia are highly compartmentalized in the submitochondrial regions. The use of redox-sensitive probes targeted to specific compartments is essential to fully understand the role of mitochondrial ROS in acute O2 sensing. Future Directions: Further studies are needed to specify the ROS and to characterize the target(s) of ROS in chemoreceptor cells during acute hypoxia. These data may also contribute to a more complete understanding of the implication of ROS in acute responses to hypoxia in O2-sensing cells in other organs. Antioxid. Redox Signal. 37, 274-289.
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Affiliation(s)
- Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Alejandro Moreno-Domínguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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9
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Langner-Hetmańczuk A, Tubek S, Niewiński P, Ponikowski P. The Role of Pharmacological Treatment in the Chemoreflex Modulation. Front Physiol 2022; 13:912616. [PMID: 35774285 PMCID: PMC9237514 DOI: 10.3389/fphys.2022.912616] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/19/2022] [Indexed: 12/20/2022] Open
Abstract
From a physiological point of view, peripheral chemoreceptors (PCh) are the main sensors of hypoxia in mammals and are responsible for adaptation to hypoxic conditions. Their stimulation causes hyperventilation—to increase oxygen uptake and increases sympathetic output in order to counteract hypoxia-induced vasodilatation and redistribute the oxygenated blood to critical organs. While this reaction promotes survival in acute settings it may be devastating when long-lasting. The permanent overfunctionality of PCh is one of the etiologic factors and is responsible for the progression of sympathetically-mediated diseases. Thus, the deactivation of PCh has been proposed as a treatment method for these disorders. We review here physiological background and current knowledge regarding the influence of widely prescribed medications on PCh acute and tonic activities.
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Affiliation(s)
- Anna Langner-Hetmańczuk
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Stanisław Tubek
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
- *Correspondence: Stanisław Tubek,
| | - Piotr Niewiński
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Piotr Ponikowski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
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10
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Conde SV, Sacramento JF, Melo BF, Fonseca-Pinto R, Romero-Ortega MI, Guarino MP. Blood Pressure Regulation by the Carotid Sinus Nerve: Clinical Implications for Carotid Body Neuromodulation. Front Neurosci 2022; 15:725751. [PMID: 35082593 PMCID: PMC8784865 DOI: 10.3389/fnins.2021.725751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
Chronic carotid sinus nerve (CSN) electrical modulation through kilohertz frequency alternating current improves metabolic control in rat models of type 2 diabetes, underpinning the potential of bioelectronic modulation of the CSN as a therapeutic modality for metabolic diseases in humans. The CSN carries sensory information from the carotid bodies, peripheral chemoreceptor organs that respond to changes in blood biochemical modifications such as hypoxia, hypercapnia, acidosis, and hyperinsulinemia. In addition, the CSN also delivers information from carotid sinus baroreceptors—mechanoreceptor sensory neurons directly involved in the control of blood pressure—to the central nervous system. The interaction between these powerful reflex systems—chemoreflex and baroreflex—whose sensory receptors are in anatomical proximity, may be regarded as a drawback to the development of selective bioelectronic tools to modulate the CSN. Herein we aimed to disclose CSN influence on cardiovascular regulation, particularly under hypoxic conditions, and we tested the hypothesis that neuromodulation of the CSN, either by electrical stimuli or surgical means, does not significantly impact blood pressure. Experiments were performed in Wistar rats aged 10–12 weeks. No significant effects of acute hypoxia were observed in systolic or diastolic blood pressure or heart rate although there was a significant activation of the cardiac sympathetic nervous system. We conclude that chemoreceptor activation by hypoxia leads to an expected increase in sympathetic activity accompanied by compensatory regional mechanisms that assure blood flow to regional beds and maintenance of hemodynamic homeostasis. Upon surgical denervation or electrical block of the CSN, the increase in cardiac sympathetic nervous system activity in response to hypoxia was lost, and there were no significant changes in blood pressure in comparison to control animals. We conclude that the responses to hypoxia and vasomotor control short-term regulation of blood pressure are dissociated in terms of hypoxic response but integrated to generate an effector response to a given change in arterial pressure.
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Affiliation(s)
- Silvia V. Conde
- Faculdade de Ciências Médicas, Chronic Disease Research Center (CEDOC), NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
- *Correspondence: Silvia V. Conde,
| | - Joana F. Sacramento
- Faculdade de Ciências Médicas, Chronic Disease Research Center (CEDOC), NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Bernardete F. Melo
- Faculdade de Ciências Médicas, Chronic Disease Research Center (CEDOC), NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Rui Fonseca-Pinto
- ciTechCare, School of Health Sciences, Polytechnic of Leiria, Leiria, Portugal
| | | | - Maria P. Guarino
- Faculdade de Ciências Médicas, Chronic Disease Research Center (CEDOC), NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
- ciTechCare, School of Health Sciences, Polytechnic of Leiria, Leiria, Portugal
- Maria P. Guarino,
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11
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Abstract
The carotid body (CB) is a bilateral arterial chemoreceptor located in the carotid artery bifurcation with an essential role in cardiorespiratory homeostasis. It is composed of highly perfused cell clusters, or glomeruli, innervated by sensory fibers. Glomus cells, the most abundant in each glomerulus, are neuron-like multimodal sensory elements able to detect and integrate changes in several physical and chemical parameters of the blood, in particular O2 tension, CO2 and pH, as well as glucose, lactate, or blood flow. Activation of glomus cells (e.g., during hypoxia or hypercapnia) stimulates the afferent fibers which impinge on brainstem neurons to elicit rapid compensatory responses (hyperventilation and sympathetic activation). This chapter presents an updated view of the structural organization of the CB and the mechanisms underlying the chemosensory responses of glomus cells, with special emphasis on the molecular processes responsible for acute O2 sensing. The properties of the glomus cell-sensory fiber synapse as well as the organization of CB output are discussed. The chapter includes the description of recently discovered CB stem cells and progenitor cells, and their role in CB growth during acclimatization to hypoxemia. Finally, the participation of the CB in the mechanisms of disease is briefly discussed.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Seville, Spain; Biomedical Research Center for Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
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12
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Abstract
Obstructive sleep apnea (OSA) is a disease that results from loss of upper airway muscle tone leading to upper airway collapse during sleep in anatomically susceptible persons, leading to recurrent periods of hypoventilation, hypoxia, and arousals from sleep. Significant clinical consequences of the disorder cover a wide spectrum and include daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic dysfunction, respiratory failure, and pulmonary hypertension. With escalating rates of obesity a major risk factor for OSA, the public health burden from OSA and its sequalae are expected to increase, as well. In this chapter, we review the mechanisms responsible for the development of OSA and associated neurocognitive and cardiometabolic comorbidities. Emphasis is placed on the neural control of the striated muscles that control the pharyngeal passages, especially regulation of hypoglossal motoneuron activity throughout the sleep/wake cycle, the neurocognitive complications of OSA, and the therapeutic options available to treat OSA including recent pharmacotherapeutic developments.
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Affiliation(s)
- Luu V Pham
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, United States.
| | - Jonathan Jun
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, United States
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13
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Csizmadia S, Fodor GH, Palkó A, Vörös E. Size of the Carotid Body in Patients with Cardiovascular and Respiratory Diseases Measured by Computed Tomography Angiography: A Case-Control Study. Radiol Res Pract 2021; 2021:9499420. [PMID: 34697571 PMCID: PMC8538397 DOI: 10.1155/2021/9499420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES Carotid bodies (CBs) play an important role in regulating sympathetic nervous system activity. Thus, they are likely to be enlarged in patients with certain cardiovascular and respiratory diseases. The aim of this case-control study was to verify this hypothesis using computed tomography angiography (CTA). METHODS We retrospectively analysed 141 CTAs including 16 controls, 96 patients with only hypertension (HT), 12 with HT and previous acute myocardial infarction (AMI), 9 with HT and heart failure (HF), and 8 with HT and chronic obstructive pulmonary disease (COPD). We assessed the data using analysis of variance, with p < 0.05 indicating significance. RESULTS CB average areas in the controls were 2.31 mm2 (right side (RS)) vs. 2.34 mm2 (left side (LS)). CB size was significantly enlarged in patients with HT: 3.07 mm2 (RS) (p=0.019) vs. 2.91 mm2 (LS) (p=0.002). If AMI (RS: 3.5 mm2; LS: 3.44 mm2) or HF (RS: 4.01 mm2; LS: 4.55 mm2) was associated with HT, the CB size was even more enlarged. COPD did not affect CB size (RS: 2.40 mm2; LS: 2.29 mm2). CONCLUSIONS Our data showed that certain diseases with increased activity of the sympathetic nervous system were associated with significantly enlarged CBs.
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Affiliation(s)
- Sándor Csizmadia
- Affidea Hungary Ltd. Budapest, 44-46 Bókay János Street, Budapest H-1083, Hungary
| | - Gergely H. Fodor
- Department of Medical Physics and Informatics, University of Szeged, Faculty of General Medicine, 9 Korányi Alley, Szeged H-6725, Hungary
| | - András Palkó
- Department of Radiology, University of Szeged, Faculty of General Medicine, 6 Semmelweis Street, Szeged H-6725, Hungary
| | - Erika Vörös
- Department of Radiology, University of Szeged, Faculty of General Medicine, 6 Semmelweis Street, Szeged H-6725, Hungary
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14
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Lages M, Carvalho L, Feijó S, Vieira A, Fonseca-Pinto R, Guarino MP. CBmeter study: protocol for assessing the predictive value of peripheral chemoreceptor overactivation for metabolic diseases. BMJ Open 2021; 11:e042825. [PMID: 34446475 PMCID: PMC8395299 DOI: 10.1136/bmjopen-2020-042825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Early screening of metabolic diseases is crucial since continued undiagnostic places an ever-increasing burden on healthcare systems. Recent studies suggest a link between overactivated carotid bodies (CB) and the genesis of type 2 diabetes mellitus. The non-invasive assessment of CB activity by measuring ventilatory, cardiac and metabolic responses to challenge tests may have predictive value for metabolic diseases; however, there are no commercially available devices that assess CB activity. The findings of the CBmeter study will clarify the role of the CBs in the genesis of-metabolic diseases and guide the development of new therapeutic approaches for early intervention in metabolic disturbances. Results may also contribute to patient classification and stratification for future CB modulatory interventions. METHODS This is a non-randomised, multicentric, controlled clinical study. Forty participants (20 control and 20 diabetics) will be recruited from secondary and primary healthcare settings. The primary objective is to establish a new model of early diagnosis of metabolic diseases based on the respiratory and metabolic responses to transient 100% oxygen administration and ingestion of a standardised mixed meal. ANALYSIS Raw data acquired with the CBmeter will be endorsed against gold standard techniques for heart rate, respiratory rate, oxygen saturation and interstitial glucose quantification and analysed a multivariate analysis software developed specifically for the CBmeter study (CBview). Data will be analysed using clustering analysis and artificial intelligence methods based on unsupervised learning algorithms, to establish the predictive value of diabetes diagnosis. ETHICS The study was approved by the Ethics Committee of the Leiria Hospital Centre. Patients will be asked for written informed consent and data will be coded to ensure the anonymity of data. DISSEMINATION Results will be disseminated through publication in peer-reviewed journals and relevant medical and health conferences.
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Affiliation(s)
- Marlene Lages
- ciTechCare - Center for Innovative Care and Health Technology, Polytechnic Institute of Leiria, Leiria, Portugal
| | - Lucinda Carvalho
- Polytechnic of Castelo Branco School of Health, Castelo Branco, Portugal
- Age.comm - Building Functional Ageing Communities, Polytechnic Institute of Castelo Branco, Castelo Branco, Portugal
| | - Salvato Feijó
- ciTechCare - Center for Innovative Care and Health Technology, Polytechnic Institute of Leiria, Leiria, Portugal
- Department of Pneumology, Leiria Hospital Centre, Leiria, Portugal
| | - Alexandra Vieira
- Department of Encrinology and Nutrition, Leiria Hospital Centre, Leiria, Portugal
| | - Rui Fonseca-Pinto
- ciTechCare - Center for Innovative Care and Health Technology, Polytechnic Institute of Leiria, Leiria, Portugal
- ESSLei - School of Health Sciences, Polytechnic Institute of Leiria, Leiria, Portugal
| | - Maria Pedro Guarino
- ciTechCare - Center for Innovative Care and Health Technology, Polytechnic Institute of Leiria, Leiria, Portugal
- ESSLei - School of Health Sciences, Polytechnic Institute of Leiria, Leiria, Portugal
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15
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Iturriaga R, Alcayaga J, Chapleau MW, Somers VK. Carotid body chemoreceptors: physiology, pathology, and implications for health and disease. Physiol Rev 2021; 101:1177-1235. [PMID: 33570461 PMCID: PMC8526340 DOI: 10.1152/physrev.00039.2019] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The carotid body (CB) is the main peripheral chemoreceptor for arterial respiratory gases O2 and CO2 and pH, eliciting reflex ventilatory, cardiovascular, and humoral responses to maintain homeostasis. This review examines the fundamental biology underlying CB chemoreceptor function, its contribution to integrated physiological responses, and its role in maintaining health and potentiating disease. Emphasis is placed on 1) transduction mechanisms in chemoreceptor (type I) cells, highlighting the role played by the hypoxic inhibition of O2-dependent K+ channels and mitochondrial oxidative metabolism, and their modification by intracellular molecules and other ion channels; 2) synaptic mechanisms linking type I cells and petrosal nerve terminals, focusing on the role played by the main proposed transmitters and modulatory gases, and the participation of glial cells in regulation of the chemosensory process; 3) integrated reflex responses to CB activation, emphasizing that the responses differ dramatically depending on the nature of the physiological, pathological, or environmental challenges, and the interactions of the chemoreceptor reflex with other reflexes in optimizing oxygen delivery to the tissues; and 4) the contribution of enhanced CB chemosensory discharge to autonomic and cardiorespiratory pathophysiology in obstructive sleep apnea, congestive heart failure, resistant hypertension, and metabolic diseases and how modulation of enhanced CB reactivity in disease conditions may attenuate pathophysiology.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, and Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Julio Alcayaga
- Laboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Mark W Chapleau
- Department of Internal Medicine, University of Iowa and Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Virend K Somers
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
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16
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Bardsley EN, Pen DK, McBryde FD, Ford AP, Paton JFR. The inevitability of ATP as a transmitter in the carotid body. Auton Neurosci 2021; 234:102815. [PMID: 33993068 DOI: 10.1016/j.autneu.2021.102815] [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] [Received: 01/25/2021] [Revised: 04/10/2021] [Accepted: 05/05/2021] [Indexed: 12/13/2022]
Abstract
Atmospheric oxygen concentrations rose markedly at several points in evolutionary history. Each of these increases was followed by an evolutionary leap in organismal complexity, and thus the cellular adaptions we see today have been shaped by the levels of oxygen within our atmosphere. In eukaryotic cells, oxygen is essential for the production of adenosine 5'-triphosphate (ATP) which is the 'Universal Energy Currency' of life. Aerobic organisms survived by evolving precise mechanisms for converting oxygen within the environment into energy. Higher mammals developed specialised organs for detecting and responding to changes in oxygen content to maintain gaseous homeostasis for survival. Hypoxia is sensed by the carotid bodies, the primary chemoreceptor organs which utilise multiple neurotransmitters one of which is ATP to evoke compensatory reflexes. Yet, a paradox is presented in oxygen sensing cells of the carotid body when during periods of low oxygen, ATP is seemingly released in abundance to transmit this signal although the synthesis of ATP is theoretically halted because of its dependence on oxygen. We propose potential mechanisms to maintain ATP production in hypoxia and summarise recent data revealing elevated sensitivity of purinergic signalling within the carotid body during conditions of sympathetic overactivity and hypertension. We propose the carotid body is hypoxic in numerous chronic cardiovascular and respiratory diseases and highlight the therapeutic potential for modulating purinergic transmission.
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Affiliation(s)
- Emma N Bardsley
- Auckland University, Department of Physiology, Faculty of Health and Medical Sciences, 85 Park Road, Grafton 1023, New Zealand
| | - Dylan K Pen
- Auckland University, Department of Physiology, Faculty of Health and Medical Sciences, 85 Park Road, Grafton 1023, New Zealand
| | - Fiona D McBryde
- Auckland University, Department of Physiology, Faculty of Health and Medical Sciences, 85 Park Road, Grafton 1023, New Zealand
| | - Anthony P Ford
- CuraSen, 930 Brittan Avenue #306, San Carlos, CA 94070, USA
| | - Julian F R Paton
- Auckland University, Department of Physiology, Faculty of Health and Medical Sciences, 85 Park Road, Grafton 1023, New Zealand.
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17
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Passino C, Sciarrone P, Vergaro G, Borrelli C, Spiesshoefer J, Gentile F, Emdin M, Giannoni A. Sacubitril-valsartan treatment is associated with decrease in central apneas in patients with heart failure with reduced ejection fraction. Int J Cardiol 2021; 330:112-119. [PMID: 33581182 DOI: 10.1016/j.ijcard.2021.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/08/2021] [Accepted: 02/03/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND To assess the impact of sacubitril-valsartan on apneic burden in patients with heart failure with reduced ejection fraction (HFrEF), 51 stable HFrEF patients planned for switching from an ACE-i/ARB to sacubitril-valsartan were prospectively enrolled. METHODS AND RESULTS At baseline and after 6 months of treatment, all patients underwent echocardiography, 24-h cardiorespiratory monitoring, neurohormonal evaluation, and cardiopulmonary exercise testing. At baseline 29% and 65% of patients presented with obstructive and central apneas, respectively. After 6 months, sacubitril-valsartan was associated with a decrease in NT-proBNP, improvement in LV function, functional capacity and ventilatory efficiency. After treatment, the apnea-hypopnea index (AHI) decreased across the 24-h period (p < 0.001), as well as at daytime (p < 0.001) and at nighttime (p = 0.026), proportionally to baseline severity. When subgrouping according to the type of apneas, daytime, nighttime and 24-h AHI decreased in patients with central apneas (all p < 0.01). Conversely, in patients with obstructive apneas, the effect of drug administration was neutral at nighttime, with significant decrease only in daytime events (p = 0.007), mainly driven by reduction in hypopneas. CONCLUSIONS Sacubitril-valsartan on top of medical treatment is associated with a reduction in the apneic burden among a real-life cohort of HFrEF patients. The most marked reduction was observed for central apneas.
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Affiliation(s)
- Claudio Passino
- Fondazione Toscana G. Monasterio, Pisa, Italy; Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.
| | | | | | | | - Jens Spiesshoefer
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy; Department of Neurology with Institute for Translational Neurology, University Hospital Muenster, Muenster, Germany
| | | | - Michele Emdin
- Fondazione Toscana G. Monasterio, Pisa, Italy; Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Alberto Giannoni
- Fondazione Toscana G. Monasterio, Pisa, Italy; Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
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18
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Keir DA, Duffin J, Floras JS. Measuring Peripheral Chemoreflex Hypersensitivity in Heart Failure. Front Physiol 2020; 11:595486. [PMID: 33447244 PMCID: PMC7802759 DOI: 10.3389/fphys.2020.595486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/30/2020] [Indexed: 01/08/2023] Open
Abstract
Heart failure with reduced ejection fraction (HFrEF) induces chronic sympathetic activation. This disturbance is a consequence of both compensatory reflex disinhibition in response to lower cardiac output and patient-specific activation of one or more excitatory stimuli. The result is the net adrenergic output that exceeds homeostatic need, which compromises cardiac, renal, and vascular function and foreshortens lifespan. One such sympatho-excitatory mechanism, evident in ~40-45% of those with HFrEF, is the augmentation of carotid (peripheral) chemoreflex ventilatory and sympathetic responsiveness to reductions in arterial oxygen tension and acidosis. Recognition of the contribution of increased chemoreflex gain to the pathophysiology of HFrEF and to patients' prognosis has focused attention on targeting the carotid body to attenuate sympathetic drive, alleviate heart failure symptoms, and prolong life. The current challenge is to identify those patients most likely to benefit from such interventions. Two assumptions underlying contemporary test protocols are that the ventilatory response to acute hypoxic exposure quantifies accurately peripheral chemoreflex sensitivity and that the unmeasured sympathetic response mirrors the determined ventilatory response. This Perspective questions both assumptions, illustrates the limitations of conventional transient hypoxic tests for assessing peripheral chemoreflex sensitivity and demonstrates how a modified rebreathing test capable of comprehensively quantifying both the ventilatory and sympathoneural efferent responses to peripheral chemoreflex perturbation, including their sensitivities and recruitment thresholds, can better identify individuals most likely to benefit from carotid body intervention.
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Affiliation(s)
- Daniel A. Keir
- University Health Network and Mount Sinai Hospital Division of Cardiology and Department of Medicine, University of Toronto, Toronto General Research Institute, Toronto, ON, Canada
- School of Kinesiology, The University of Western Ontario, London, ON, Canada
| | - James Duffin
- Department of Anesthesia and Pain Management, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Thornhill Research Inc., Toronto, ON, Canada
| | - John S. Floras
- University Health Network and Mount Sinai Hospital Division of Cardiology and Department of Medicine, University of Toronto, Toronto General Research Institute, Toronto, ON, Canada
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19
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Ortega-Sáenz P, Moreno-Domínguez A, Gao L, López-Barneo J. Molecular Mechanisms of Acute Oxygen Sensing by Arterial Chemoreceptor Cells. Role of Hif2α. Front Physiol 2020; 11:614893. [PMID: 33329066 PMCID: PMC7719705 DOI: 10.3389/fphys.2020.614893] [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: 10/07/2020] [Accepted: 11/03/2020] [Indexed: 01/28/2023] Open
Abstract
Carotid body glomus cells are multimodal arterial chemoreceptors able to sense and integrate changes in several physical and chemical parameters in the blood. These cells are also essential for O2 homeostasis. Glomus cells are prototypical peripheral O2 sensors necessary to detect hypoxemia and to elicit rapid compensatory responses (hyperventilation and sympathetic activation). The mechanisms underlying acute O2 sensing by glomus cells have been elusive. Using a combination of mouse genetics and single-cell optical and electrophysiological techniques, it has recently been shown that activation of glomus cells by hypoxia relies on the generation of mitochondrial signals (NADH and reactive oxygen species), which modulate membrane ion channels to induce depolarization, Ca2+ influx, and transmitter release. The special sensitivity of glomus cell mitochondria to changes in O2 tension is due to Hif2α-dependent expression of several atypical mitochondrial subunits, which are responsible for an accelerated oxidative metabolism and the strict dependence of mitochondrial complex IV activity on O2 availability. A mitochondrial-to-membrane signaling model of acute O2 sensing has been proposed, which explains existing data and provides a solid foundation for future experimental tests. This model has also unraveled new molecular targets for pharmacological modulation of carotid body activity potentially relevant in the treatment of highly prevalent medical conditions.
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Affiliation(s)
- Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Alejandro Moreno-Domínguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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20
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N-acetylcysteine prevents verapamil-induced cardiotoxicity with no effect on the noradrenergic arch-associated neurons in zebrafish. Food Chem Toxicol 2020; 144:111559. [PMID: 32640352 DOI: 10.1016/j.fct.2020.111559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/16/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
There is a strong association between calcium channel blockers (CCBs) and heart failure. CCB toxicity is very common due to overdose and underlying medical conditions. CCBs also have been shown to affect the nervous system. Recently, we demonstrated that the antioxidant N-acetylcysteine (NAC) prevented ketamine-induced cardiotoxicity, developmental toxicity and neurotoxicity. Functionally, we attributed NAC's beneficial effect to its ability to increase cellular calcium. Here, we hypothesized that if there was an involvement of calcium in NAC's preventative effects on ketamine toxicity, NAC might also ameliorate toxicities induced by verapamil, an L-type CCB used to treat hypertension. Using zebrafish embryos, we show that in the absence of NAC, verapamil (up to 100 μM) dose-dependently reduced heart rate and those effects were prevented by NAC co-treatment. Furthermore, a 2-h treatment with NAC rescued reduction of heart rate induced by pre-treatment of 50 and 100 μM of verapamil for 18 h. Verapamil up to 100 μM and NAC up to 1.5 mM did not have any adverse effects on the expression of tyrosine hydroxylase in the noradrenergic neurons of the arch-associated cluster (AAC) located near the heart. NAC did not change cysteine levels in the embryos suggesting that the beneficial effect of NAC on verapamil toxicity may not involve its antioxidant property. In our search for compounds that can prevent CCB toxicity, this study, for the first time, demonstrates protective effects of NAC against verapamil's adverse effects on the heart.
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21
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Katayama PL, Abdala AP, Charles I, Pijacka W, Salgado HC, Gever J, Ford AP, Paton JFR. P2X3 receptor antagonism reduces the occurrence of apnoeas in newborn rats. Respir Physiol Neurobiol 2020; 277:103438. [PMID: 32259688 PMCID: PMC8208833 DOI: 10.1016/j.resp.2020.103438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/27/2020] [Accepted: 03/25/2020] [Indexed: 11/17/2022]
Abstract
Hyperreflexia of the peripheral chemoreceptors is a potential contributor of apnoeas of prematurity (AoP). Recently, it was shown that elevated P2X3 receptor expression was associated with elevated carotid body afferent sensitivity. Therefore, we tested whether P2X3 receptor antagonism would reduce AoP known to occur in newborn rats. Unrestrained whole-body plethysmography was used to record breathing and from this the frequency of apnoeas at baseline and following administration of either a P2X3 receptor antagonist - AF-454 (5 mg/kg or 10 mg/kg s.c.) or vehicle was derived. In a separate group, we tested the effects of AF-454 (10 mg/kg) on the hypoxic ventilatory response (10 % FiO2). Ten but not 5 mg/kg AF-454 reduced the frequency of AoP and improved breathing regularity significantly compared to vehicle. Neither AF-454 (both 5 and 10 mg/kg) nor vehicle affected baseline respiration. However, P2X3 receptor antagonism (10 mg/kg) powerfully blunted hypoxic ventilatory response to 10 % FiO2. These data suggest that P2X3 receptors contribute to AoP and the hypoxic ventilatory response in newborn rats but play no role in the drive to breathe at rest.
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Affiliation(s)
- Pedro Lourenço Katayama
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, BS8 1TD, England, UK; Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ana Paula Abdala
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, BS8 1TD, England, UK
| | - Ian Charles
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, BS8 1TD, England, UK
| | - Wioletta Pijacka
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, BS8 1TD, England, UK; Department of Cardiovascular, Renal and Metabolism, MedImmune Ltd, Granta Park, Cambridge, UK
| | - Helio Cesar Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Joel Gever
- Afferent Pharmaceuticals, San Mateo, CA, USA
| | | | - Julian F R Paton
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, BS8 1TD, England, UK; Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Park Road, Grafton, Auckland, 1142, New Zealand.
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22
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Otlyga DA, Junemann OA, Dzhalilova DS, Tsvetkova EG, Saveliev SV. Immunohistochemical Study of Dark and Progenitor Carotid Body Cells: Artefacts or Real Subtypes? Bull Exp Biol Med 2020; 168:807-811. [PMID: 32328951 DOI: 10.1007/s10517-020-04807-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Indexed: 01/24/2023]
Abstract
Postmortem changes occurring in human carotid body were simulated on the Wistar rat model. It was shown that light, dark, and pyknotic (progenitor) subtypes of human carotid body cells are an artifact and cannot be used in clinical practice to study the characteristics of various human diseases. The differences between the control group of healthy individuals and individuals with the various pathologies are most likely due to the different levels of premortal hypoxia that the tissue had been exposed to. Moreover, widespread antigens used in practice were divided into 2 groups by their tolerance to autolysis: stable and unstable ones. This can be useful for the development of immunohistochemical test algorithms for the diagnostics on autopsy material.
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Affiliation(s)
- D A Otlyga
- Research Institute of Human Morphology, Moscow, Russia.
| | - O A Junemann
- Research Institute of Human Morphology, Moscow, Russia
| | | | - E G Tsvetkova
- I. M. Sechenov First Moscow State Medical University, Ministry of Health of the Russian Federation (Sechenov University), Moscow, Russia
| | - S V Saveliev
- Research Institute of Human Morphology, Moscow, Russia
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23
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Dale EA, Kipke J, Kubo Y, Sunshine MD, Castro PA, Ardell JL, Mahajan A. Spinal cord neural network interactions: implications for sympathetic control of the porcine heart. Am J Physiol Heart Circ Physiol 2020; 318:H830-H839. [PMID: 32108524 DOI: 10.1152/ajpheart.00635.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inherent and acquired factors determine the integrated autonomic response to cardiovascular stressors. Excessive sympathoexcitation to ischemic stress is a major contributor to the potential for sudden cardiac death. To define fundamental aspects of cardiac-related autonomic neural network interactions within the thoracic cord, specifically as related to modulating sympathetic preganglionic (SPN) neural activity. Adult, anesthetized Yorkshire pigs (n = 10) were implanted with penetrating high-density microarrays (64 electrodes) at the T2 level of the thoracic spinal cord to record extracellular potentials concurrently from left-sided dorsal horn (DH) and SPN neurons. Electrical stimulation of the T2 paravertebral chain allowed for antidromic identification of SPNs located in the intermediolateral cell column (57 of total 1,760 recorded neurons). Cardiac stressors included epicardial touch, occlusion of great vessels to transiently alter preload/afterload, and transient occlusion of the left anterior descending coronary artery (LAD). Spatial/temporal assessment of network interactions was characterized by cross-correlation analysis. While some DH neurons responded solely to changes in preload/afterload (8.5 ± 1.9%) or ischemic stress (10.5 ± 3.9%), the majority of cardiovascular-related DH neurons were multimodal (30.2 ± 4.7%) with ischemia sensitivity being one of the modalities (26.1 ± 4.7%). The sympathoexcitation associated with transient LAD occlusion was associated with increased correlations from baseline within DH neurons (2.43 ± 0.61 to 7.30 ± 1.84%, P = 0.04) and between SPN to DH neurons (1.32 ± 0.78 to 7.24 ± 1.84%, P = 0.02). DH to SPN network correlations were reduced during great vessel occlusion. In conclusion, increased intrasegmental network coherence within the thoracic spinal cord contributes to myocardial ischemia-induced sympathoexcitation.NEW & NOTEWORTHY In an in vivo pig model, we demonstrate using novel high-resolution neural electrode arrays that increased intrasegmental network coherence within the thoracic spinal cord contributes to myocardial ischemia-induced sympathoexcitation.
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Affiliation(s)
- Erica A Dale
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Jasmine Kipke
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Yukiko Kubo
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Michael D Sunshine
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Peter A Castro
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Jeffrey L Ardell
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, California.,Department of Medicine, Cardiac Arrhythmia Center and Cardiac Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Aman Mahajan
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, California
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24
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Abstract
The carotid body (CB) is an arterial chemoreceptor organ located in the carotid bifurcation and has a well-recognized role in cardiorespiratory regulation. The CB contains neurosecretory sensory cells (glomus cells), which release transmitters in response to hypoxia, hypercapnia, and acidemia to activate afferent sensory fibers terminating in the respiratory and autonomic brainstem centers. Knowledge of the physiology of the CB has progressed enormously in recent years. Herein we review advances concerning the organization and function of the cellular elements of the CB, with emphasis on the molecular mechanisms of acute oxygen sensing by glomus cells. We introduce the modern view of the CB as a multimodal integrated metabolic sensor and describe the properties of the CB stem cell niche, which support CB growth during acclimatization to chronic hypoxia. Finally, we discuss the increasing medical relevance of CB dysfunction and its potential impact on the mechanisms of disease.
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Affiliation(s)
- Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41013, Spain; , .,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sevilla 41013, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41013, Spain; , .,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sevilla 41013, Spain
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25
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Byers BW, Fuhr DP, Moore LE, Bhutani M, Wong EYL, Stickland MK. The effect of pulmonary rehabilitation on carotid chemoreceptor activity and sensitivity in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2019; 127:1278-1287. [PMID: 31295067 DOI: 10.1152/japplphysiol.00799.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent work demonstrates that carotid chemoreceptor (CC) activity/sensitivity is elevated in patients with chronic obstructive pulmonary disease (COPD) compared with healthy controls, and this elevated chemoreception appears to contribute to increased cardiovascular risk. Exercise training has been shown to normalize CC activity/sensitivity in other populations, and therefore, the purpose of this study was to determine whether pulmonary rehabilitation (PR) can reduce CC activity/sensitivity in COPD. Forty-five COPD patients [mean FEV1 (forced expiratory volume in 1 s) = 56.6% predicted] completed PR, while 15 COPD patients (mean FEV1 = 74.6% predicted) served as non-PR controls. CC activity was determined by the reduction in ventilation while breathing transient hyperoxia ([Formula: see text] = 1.0); CC sensitivity was evaluated by the increase in ventilation relative to the drop in arterial saturation while breathing hypoxia. Dyspnea, six-minute walk and autonomic function data were also obtained. PR improved 6-minute walk distance (P < 0.001) and dyspnea (P = 0.04); however, there was no effect on CC activity (P = 0.60), sensitivity (P = 0.69), or autonomic function (P > 0.05 for all). Subgroup analyses indicated that PR reduced CC activity in those with elevated baseline CC activity, independent of changes in autonomic function. No change in dyspnea (P = 0.24), CC activity (P = 0.19), sensitivity (P = 0.80), or autonomic function (P > 0.05 for all) was observed in the control group. Despite improvements in exercise tolerance and dyspnea, PR appears to be generally ineffective at reducing CC sensitivity in stable COPD patients; while PR reduced CC activity in those with elevated basal CC activity, the physiological significance of this is unclear. Further investigations aimed at improving CC function in COPD are needed.NEW & NOTEWORTHY While work in other chronic diseases has shown that exercise training may help normalize carotid chemoreceptor (CC) activity/sensitivity, the current study found that exercise training through pulmonary rehabilitation did not consistently reduce CC activity/sensitivity in patients with chronic obstructive pulmonary disease (COPD). These results suggest that other interventions are needed to normalize CC activity/sensitivity in COPD.
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Affiliation(s)
- Bradley W Byers
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Desi P Fuhr
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Linn E Moore
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Mohit Bhutani
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Eric Y L Wong
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael K Stickland
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,G. F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, Alberta, Canada
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26
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Salavatian S, Ardell SM, Hammer M, Gibbons D, Armour JA, Ardell JL. Thoracic spinal cord neuromodulation obtunds dorsal root ganglion afferent neuronal transduction of the ischemic ventricle. Am J Physiol Heart Circ Physiol 2019; 317:H1134-H1141. [PMID: 31538809 DOI: 10.1152/ajpheart.00257.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Aberrant afferent signaling drives adverse remodeling of the cardiac nervous system in ischemic heart disease. The study objective was to determine whether thoracic spinal dorsal column stimulation (SCS) modulates cardiac afferent sensory transduction of the ischemic ventricle. In anesthetized canines (n = 16), extracellular activity generated by 62 dorsal root ganglia (DRG) soma (T1-T3), with verified myocardial ischemic (MI) sensitivity, were evaluated with and without 20-min preemptive SCS (T1-T3 spinal level; 50 Hz, 90% motor threshold). Transient MI was induced by 1-min coronary artery occlusion (CAO) of the left anterior descending (LAD) or circumflex (LCX) artery, randomized as to sequence. LAD and LCX CAO activated cardiac-related DRG neurons (LAD: 0.15 ± 0.04-1.05 ± 0.20 Hz, P < 0.00002; LCX: 0.08 ± 0.02-1.90 ± 0.45 Hz, P < 0.0003). SCS decreased basal neuronal activity of neurons that responded to LAD (0.15 ± 0.04 to 0.02 ± 0.01 Hz, P < 0.006) and LCX (0.08 ± 0.02 to 0.02 ± 0.01 Hz, P < 0.003). SCS suppressed responsiveness to transient MI (LAD: 1.05 ± 0.20-0.03 ± 0.01 Hz; P < 0.0001; LCX: 1.90 ± 0.45-0.03 ± 0.01 Hz; P < 0.001). Suprathreshold SCS (1 Hz) did not activate DRG neurons antidromically (n = 10 animals). Ventricular fibrillation (VF) was associated with a rapid increase in DRG activity to a maximum of 4.39 ± 1.07 Hz at 20 s after VF induction and a return to 90% of baseline within 10 s thereafter. SCS obtunds the capacity of DRG ventricular neurites to transduce the ischemic myocardium to second-order spinal neurons, a mechanism that would blunt reflex sympathoexcitation to myocardial ischemic stress, thereby contributing to its capacity to cardioprotect.NEW & NOTEWORTHY Aberrant afferent signaling drives adverse remodeling of the cardiac nervous system in ischemic heart disease. This study determined that thoracic spinal column stimulation (SCS) obtunds the capacity of dorsal root ganglia ventricular afferent neurons to transduce the ischemic myocardium to second-order spinal neurons, a mechanism that would blunt reflex sympathoexcitation to myocardial ischemic stress. This modulation does not reflect antidromic actions of SCS but likely reflects efferent-mediated changes at the myocyte-sensory neurite interface.
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Affiliation(s)
- Siamak Salavatian
- Neurocardiology Research Program of Excellence, University of California, Los Angeles, California.,Cardiac Arrhythmia Center, University of California, Los Angeles, California
| | - Sarah M Ardell
- Neurocardiology Research Program of Excellence, University of California, Los Angeles, California.,Cardiac Arrhythmia Center, University of California, Los Angeles, California
| | - Mathew Hammer
- Neurocardiology Research Program of Excellence, University of California, Los Angeles, California.,Cardiac Arrhythmia Center, University of California, Los Angeles, California
| | - David Gibbons
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - J Andrew Armour
- Neurocardiology Research Program of Excellence, University of California, Los Angeles, California.,Cardiac Arrhythmia Center, University of California, Los Angeles, California
| | - Jeffrey L Ardell
- Neurocardiology Research Program of Excellence, University of California, Los Angeles, California.,Cardiac Arrhythmia Center, University of California, Los Angeles, California
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Castania JA, Katayama PL, Brognara F, Moraes DJA, Sabino JPJ, Salgado HC. Selective denervation of the aortic and carotid baroreceptors in rats. Exp Physiol 2019; 104:1335-1342. [PMID: 31161612 DOI: 10.1113/ep087764] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/03/2019] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? The traditional surgical approach for sino-aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation, which does not permit their individual study in different situations. What is the main finding and its importance? We have described a new surgical approach capable of selective denervation of the arterial (aortic and carotid) baroreceptors, keeping the carotid bodies (chemoreceptors) intact. It is understood that this technique might be a useful tool for investigating the relative role of the baro- and chemoreceptors in several physiological and pathophysiological conditions. ABSTRACT Studies have demonstrated that the traditional surgical approach for sino-aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation. The present study reports a new surgical approach to denervate the aortic and the carotid baroreceptors selectively, keeping the carotid bodies (peripheral chemoreceptors) intact. Wistar rats were subjected to specific aortic and carotid baroreceptor denervation (BAROS-X) or sham surgery (SHAM). Baroreflex activation was achieved by i.v. administration of phenylephrine, whereas peripheral chemoreflex activation was produced by i.v. administration of potassium cyanide. The SHAM and BAROS-X rats displayed significant hypertensive responses to phenylephrine administration. However, the reflex bradycardia following the hypertensive response caused by phenylephrine was remarkable in SHAM, but not significant in the BAROS-X animals, confirming the efficacy of the surgical procedure to abolish the baroreflex. In addition, the baroreflex activation elicited by phenylephrine increased carotid sinus nerve activity only in SHAM, but not in the BAROS-X animals, providing support to the notion that the baroreceptor afferents were absent. Instead, the classical peripheral chemoreflex hypertensive and bradycardic responses to potassium cyanide were similar in both groups, suggesting that the carotid body chemoreceptors were preserved after BAROS-X. In summary, we describe a new surgical approach in which only the baroreceptors are eliminated, while the carotid chemoreceptors are preserved. Therefore, it is understood that this procedure is potentially a useful tool for examining the relative roles of the arterial baroreceptors versus the chemoreceptors in several pathophysiological conditions, for instance, arterial hypertension and heart failure.
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Affiliation(s)
- Jaci A Castania
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Pedro L Katayama
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fernanda Brognara
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Davi J A Moraes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - João Paulo J Sabino
- Department of Biophysics and Physiology, Federal University of Piauí, Teresina, Piauí, Brazil
| | - Helio C Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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28
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Abstract
PURPOSE OF REVIEW An abnormal heightened carotid body (CB) chemoreflex, which produces autonomic dysfunction and sympathetic overactivation, is the common hallmark of obstructive sleep apnea (OSA), resistant hypertension, systolic heart failure (HF), and cardiometabolic diseases. Accordingly, it has been proposed that the elimination of the CB chemosensory input to the brainstem may reduce the autonomic and cardiorespiratory alterations in sympathetic-associated diseases in humans. RECENT FINDINGS A growing body of evidence obtained in preclinical animal models support that an enhanced CB discharge produces sympathetic hyperactivity, baroreflex sensitivity and heart rate variability impairment, breathing instability, hypertension, and insulin resistance. The elimination CB chemosensory input reduces the sympathetic hyperactivity, the elevated arterial blood pressure in OSA and hypertensive models, abolishes breathing instability and improves animal survival in HF models, and restores insulin tolerance in metabolic models. These results highlight the role played by the enhanced CB drive in the progression of sympathetic-related diseases and support the proposal that the surgical ablation of the CB is useful to restore the autonomic balance and normal cardiorespiratory function in humans. Accordingly, the CB ablation has been used in pilot human studies as a therapeutic treatment for resistant hypertension and HF-induced sympathetic hyperactivity. In this review, I will discuss the supporting evidence for a crucial contribution of the CB in the central autonomic dysfunction and the pros and cons of the CB ablation as a therapy to revert autonomic overactivation. The CB ablation could be a useful method to reverse the enhanced chemoreflex in HF and severe hypertension, but caution is required before extensive use of bilateral CB ablation, which abolished ventilatory responses to hypoxia and may impair baroreceptor function.
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29
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Kang D, Wang J, Hogan JO, Kim D. TASK-1 (K2P3) and TASK-3 (K2P9) in Rabbit Carotid Body Glomus Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1071:35-41. [DOI: 10.1007/978-3-319-91137-3_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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30
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Neuromodulation Therapies for Cardiac Disease. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00129-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Sheikhbahaei S, Gourine AV, Smith JC. Respiratory rhythm irregularity after carotid body denervation in rats. Respir Physiol Neurobiol 2017; 246:92-97. [PMID: 28782663 PMCID: PMC5637156 DOI: 10.1016/j.resp.2017.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 07/09/2017] [Accepted: 08/01/2017] [Indexed: 12/13/2022]
Abstract
Respiratory activity is controlled by inputs from the peripheral and central chemoreceptors. Since overactivity of the carotid bodies, the main peripheral chemoreceptors, is linked to the pathophysiology of disparate metabolic and cardiovascular diseases, carotid body denervation (CBD) has been proposed as a potential treatment. However, long-term effects of CBD on the respiratory rhythm and regularity of breathing remain unknown. Here, we show that five weeks after bilateral CBD in rats, the respiratory rhythm was slower and less regular. Ten weeks after bilateral CBD, the respiratory frequency was not different from the sham-operated group, but the regularity of the respiratory rhythm was still reduced. Increased frequency of randomly occurring apneas is likely to be responsible for the irregular breathing pattern after CBD. These results should be taken into consideration since any treatment that reduces the stability of the respiratory rhythm might exacerbate the cardio-respiratory instability and worsen the cardiovascular outcomes.
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Affiliation(s)
- Shahriar Sheikhbahaei
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA; Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, UK.
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, UK
| | - Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
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32
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Iturriaga R. Translating carotid body function into clinical medicine. J Physiol 2017; 596:3067-3077. [PMID: 29114876 DOI: 10.1113/jp275335] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022] Open
Abstract
The carotid body (CB) is considered the main O2 chemoreceptor, which contributes to cardiorespiratory homeostasis and ventilatory acclimatization. In clinical medicine, the most common pathologies associated with the CB are tumours. However, a growing body of evidence supports the novel idea that an enhanced CB chemosensory discharge contributes to the autonomic dysfunction and pathological consequences in obstructive sleep apnoea (OSA), hypertension, systolic heart failure (HF) and cardiometabolic diseases. Heightened CB chemosensory reactivity elicited by oxidative stress has been involved in sympathetic hyperactivity, cardiorespiratory instability, hypertension and insulin resistance. CB ablation, which reduces sympathetic hyperactivity, decreases hypertension in animal models of OSA and hypertension, eliminates breathing instability and improves animal survival in HF, and restores insulin tolerance in cardiometabolic models. Thus, data obtained from preclinical studies highlight the importance of the CB in the progression of sympathetic-related diseases, supporting the idea that appeasing the enhanced CB chemosensory drive may be useful in improving cardiovascular, respiratory and endocrine alterations. Accordingly, CB ablation has been proposed and used as a treatment for moderating resistant hypertension and HF-induced sympathetic hyperactivity in humans. First-in-human studies have shown that CB ablation reduces sympathetic overactivity, transiently reduces severe hypertension and improves quality of life in HF patients. Thus, CB ablation would be a useful therapy to reverse sympathetic overactivation in HF and severe hypertension, but caution is required before it is widely used due to the crucial physiological function played by the CB. Further studies in preclinical models are required to assess side-effects of CB ablation.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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33
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Andrade DC, Arce-Alvarez A, Toledo C, Díaz HS, Lucero C, Quintanilla RA, Schultz HD, Marcus NJ, Amann M, Del Rio R. Revisiting the physiological effects of exercise training on autonomic regulation and chemoreflex control in heart failure: does ejection fraction matter? Am J Physiol Heart Circ Physiol 2017; 314:H464-H474. [PMID: 29167119 DOI: 10.1152/ajpheart.00407.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heart failure (HF) is a global public health problem that, independent of its etiology [reduced (HFrEF) or preserved ejection fraction (HFpEF)], is characterized by functional impairments of cardiac function, chemoreflex hypersensitivity, baroreflex sensitivity (BRS) impairment, and abnormal autonomic regulation, all of which contribute to increased morbidity and mortality. Exercise training (ExT) has been identified as a nonpharmacological therapy capable of restoring normal autonomic function and improving survival in patients with HFrEF. Improvements in autonomic function after ExT are correlated with restoration of normal peripheral chemoreflex sensitivity and BRS in HFrEF. To date, few studies have addressed the effects of ExT on chemoreflex control, BRS, and cardiac autonomic control in HFpEF; however, there are some studies that have suggested that ExT has a beneficial effect on cardiac autonomic control. The beneficial effects of ExT on cardiac function and autonomic control in HF may have important implications for functional capacity in addition to their obvious importance to survival. Recent studies have suggested that the peripheral chemoreflex may also play an important role in attenuating exercise intolerance in HFrEF patients. The role of the central/peripheral chemoreflex, if any, in mediating exercise intolerance in HFpEF has not been investigated. The present review focuses on recent studies that address primary pathophysiological mechanisms of HF (HFrEF and HFpEF) and the potential avenues by which ExT exerts its beneficial effects.
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Affiliation(s)
- David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación en Fisiología del Ejercicio, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Alexis Arce-Alvarez
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | - Claudia Lucero
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | | | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center , Omaha, Nebraska
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University , Des Moines, Iowa
| | - Markus Amann
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes , Punta Arenas , Chile.,Centro de Envejecimiento y Regeneracion, Pontificia Universidad Católica de Chile, Santiago, Chile
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34
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Carotid Body-Mediated Chemoreflex Drive in The Setting of low and High Output Heart Failure. Sci Rep 2017; 7:8035. [PMID: 28808320 PMCID: PMC5556057 DOI: 10.1038/s41598-017-08142-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 07/05/2017] [Indexed: 12/20/2022] Open
Abstract
Enhanced carotid body (CB) chemoreflex function is strongly related to cardiorespiratory disorders and disease progression in heart failure (HF). The mechanisms underlying CB sensitization during HF are not fully understood, however previous work indicates blood flow per se can affect CB function. Then, we hypothesized that the CB-mediated chemoreflex drive will be enhanced only in low output HF but not in high output HF. Myocardial infarcted rats and aorto-caval fistulated rats were used as a low output HF model (MI-CHF) and as a high output HF model (AV-CHF), respectively. Blood flow supply to the CB region was decreased only in MI-CHF rats compared to Sham and AV-CHF rats. MI-CHF rats exhibited a significantly enhanced hypoxic ventilatory response compared to AV-CHF rats. However, apnea/hypopnea incidence was similarly increased in both MI-CHF and AV-CHF rats compared to control. Kruppel-like factor 2 expression, a flow sensitive transcription factor, was reduced in the CBs of MI-CHF rats but not in AV-CHF rats. Our results indicate that in the setting of HF, potentiation of the CB chemoreflex is strongly associated with a reduction in cardiac output and may not be related to other pathophysiological consequences of HF.
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35
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Moderate inhibition of mitochondrial function augments carotid body hypoxic sensitivity. Pflugers Arch 2016; 468:143-155. [PMID: 26490460 DOI: 10.1007/s00424-015-1745-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 10/01/2015] [Accepted: 10/06/2015] [Indexed: 12/21/2022]
Abstract
A functional role for the mitochondria in acute O2 sensing in the carotid body (CB) remains undetermined. Whilst total inhibition of mitochondrial activity causes intense CB stimulation, it is unclear whether this response can be moderated such that graded impairment of oxidative phosphorylation might be a mechanism that sets and modifies the O2 sensitivity of the whole organ. We assessed NADH autofluorescence and [Ca2+]i in freshly dissociated CB type I cells and sensory chemoafferent discharge frequency in an intact CB preparation, in the presence of varying concentrations of nitrite (NO2 −), a mitochondrial nitric oxide (NO) donor and a competitive inhibitor of mitochondrial complex IV. NO2 − increased CB type I cell NADH in a manner that was dose-dependent and rapidly reversible. Similar concentrations of NO2 − raised type I cell [Ca2+]i via L-type channels in a PO2-dependent manner and increased chemoafferent discharge frequency. Moderate inhibition of the CB mitochondria by NO2 − augmented chemoafferent discharge frequency during graded hypoxia, consistent with a heightened CB O2 sensitivity. Furthermore, NO2 − also exaggerated chemoafferent excitation during hypercapnia signifying an increase in CB CO2 sensitivity. These data show that NO2 − can moderate the hypoxia sensitivity of the CB and thus suggest that O2 sensitivity could be set and modified in this organ by interactions between NO and mitochondrial complex IV.
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36
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MacIver DH, Adeniran I, MacIver IR, Revell A, Zhang H. Physiological mechanisms of pulmonary hypertension. Am Heart J 2016; 180:1-11. [PMID: 27659877 DOI: 10.1016/j.ahj.2016.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 07/05/2016] [Indexed: 12/25/2022]
Abstract
Pulmonary hypertension is usually related to obstruction of pulmonary blood flow at the level of the pulmonary arteries (eg, pulmonary embolus), pulmonary arterioles (idiopathic pulmonary hypertension), pulmonary veins (pulmonary venoocclusive disease) or mitral valve (mitral stenosis and regurgitation). Pulmonary hypertension is also observed in heart failure due to left ventricle myocardial diseases regardless of the ejection fraction. Pulmonary hypertension is often regarded as a passive response to the obstruction to pulmonary flow. We review established fluid dynamics and physiology and discuss the mechanisms underlying pulmonary hypertension. The important role that the right ventricle plays in the development and maintenance of pulmonary hypertension is discussed. We use principles of thermodynamics and discuss a potential common mechanism for a number of disease states, including pulmonary edema, through adding pressure energy to the pulmonary circulation.
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Affiliation(s)
- David H MacIver
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom; Department of Cardiology, Taunton & Somerset Hospital, Musgrove Park, Taunton, United Kingdom; Medical Education, University of Bristol, Senate House, Tyndall Avenue, Bristol, United Kingdom.
| | - Ismail Adeniran
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom
| | - Iain R MacIver
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom
| | - Alistair Revell
- Modelling & Simulation Centre, School of Mechanical, Aerospace & Civil Engineering, University of Manchester, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom
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37
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Tubek S, Niewinski P, Reczuch K, Janczak D, Rucinski A, Paleczny B, Engelman ZJ, Banasiak W, Paton JFR, Ponikowski P. Effects of selective carotid body stimulation with adenosine in conscious humans. J Physiol 2016; 594:6225-6240. [PMID: 27435894 DOI: 10.1113/jp272109] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/12/2016] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS In humans, excitation of peripheral chemoreceptors with systemic hypoxia causes hyperventilation, hypertension and tachycardia. However, the contribution of particular chemosensory areas (carotid vs. aortic bodies) to this response is unclear. We showed that selective stimulation of the carotid body by the injection of adenosine into the carotid artery causes a dose-dependent increase in minute ventilation and blood pressure with a concomitant decrease in heart rate in conscious humans. The ventilatory response was abolished and the haemodynamic response was diminished following carotid body ablation. We found that the magnitude of adenosine evoked responses in minute ventilation and blood pressure was analogous to the responses evoked by hypoxia. By contrast, opposing heart rate responses were evoked by adenosine (bradycardia) vs. hypoxia (tachycardia). Intra-carotid adenosine administration may provide a novel method for perioperative assessment of the effectiveness of carotid body ablation, which has been recently proposed as a treatment strategy for sympathetically-mediated diseases. ABSTRACT Stimulation of peripheral chemoreceptors by acute hypoxia causes an increase in minute ventilation (VI), heart rate (HR) and arterial blood pressure (BP). However, the contribution of particular chemosensory areas, such as carotid (CB) vs. aortic bodies, to this response in humans remains unknown. We performed a blinded, randomized and placebo-controlled study in 11 conscious patients (nine men, two women) undergoing common carotid artery angiography. Doses of adenosine ranging from 4 to 512 μg or placebo solution of a matching volume were administered in randomized order via a diagnostic catheter located in a common carotid artery. Separately, ventilatory and haemodynamic responses to systemic hypoxia were also assessed. Direct excitation of a CB with intra-arterial adenosine increased VI, systolic BP, mean BP and decreased HR. No responses in these variables were seen after injections of placebo. The magnitude of the ventilatory and haemodynamic responses depended on both the dose of adenosine used and on the level of chemosensitivity as determined by the ventilatory response to hypoxia. Percutaneous radiofrequency ablation of the CB abolished the adenosine evoked respiratory response and partially depressed the cardiovascular response in one participant. The results of the present study confirm the excitatory role of purines in CB physiology in humans and suggest that adenosine may be used for selective stimulation and assessment of CB activity. The trial is registered at ClinicalTrials.gov NCT01939912.
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Affiliation(s)
- Stanislaw Tubek
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland. .,Department of Heart Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland.
| | - Piotr Niewinski
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Krzysztof Reczuch
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.,Department of Heart Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
| | - Dariusz Janczak
- Department of Vascular Surgery, 4th Military Hospital, Wroclaw, Poland.,Department of Clinical Proceedings, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
| | - Artur Rucinski
- Department of Vascular Surgery, 4th Military Hospital, Wroclaw, Poland
| | | | | | - Waldemar Banasiak
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Piotr Ponikowski
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.,Department of Heart Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
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38
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Ardell JL, Andresen MC, Armour JA, Billman GE, Chen PS, Foreman RD, Herring N, O'Leary DS, Sabbah HN, Schultz HD, Sunagawa K, Zucker IH. Translational neurocardiology: preclinical models and cardioneural integrative aspects. J Physiol 2016; 594:3877-909. [PMID: 27098459 DOI: 10.1113/jp271869] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/14/2016] [Indexed: 12/15/2022] Open
Abstract
Neuronal elements distributed throughout the cardiac nervous system, from the level of the insular cortex to the intrinsic cardiac nervous system, are in constant communication with one another to ensure that cardiac output matches the dynamic process of regional blood flow demand. Neural elements in their various 'levels' become differentially recruited in the transduction of sensory inputs arising from the heart, major vessels, other visceral organs and somatic structures to optimize neuronal coordination of regional cardiac function. This White Paper will review the relevant aspects of the structural and functional organization for autonomic control of the heart in normal conditions, how these systems remodel/adapt during cardiac disease, and finally how such knowledge can be leveraged in the evolving realm of autonomic regulation therapy for cardiac therapeutics.
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Affiliation(s)
- J L Ardell
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - M C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - J A Armour
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - G E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - P-S Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R D Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - N Herring
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - D S O'Leary
- Department of Physiology, Wayne State University, Detroit, MI, USA
| | - H N Sabbah
- Department of Medicine, Henry Ford Hospital, Detroit, MI, USA
| | - H D Schultz
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - K Sunagawa
- Department of Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - I H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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39
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Thompson EL, Ray CJ, Holmes AP, Pye RL, Wyatt CN, Coney AM, Kumar P. Adrenaline release evokes hyperpnoea and an increase in ventilatory CO2 sensitivity during hypoglycaemia: a role for the carotid body. J Physiol 2016; 594:4439-52. [PMID: 27027261 DOI: 10.1113/jp272191] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 03/18/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Hypoglycaemia is counteracted by release of hormones and an increase in ventilation and CO2 sensitivity to restore blood glucose levels and prevent a fall in blood pH. The full counter-regulatory response and an appropriate increase in ventilation is dependent on carotid body stimulation. We show that the hypoglycaemia-induced increase in ventilation and CO2 sensitivity is abolished by preventing adrenaline release or blocking its receptors. Physiological levels of adrenaline mimicked the effect of hypoglycaemia on ventilation and CO2 sensitivity. These results suggest that adrenaline, rather than low glucose, is an adequate stimulus for the carotid body-mediated changes in ventilation and CO2 sensitivity during hypoglycaemia to prevent a serious acidosis in poorly controlled diabetes. ABSTRACT Hypoglycaemia in vivo induces a counter-regulatory response that involves the release of hormones to restore blood glucose levels. Concomitantly, hypoglycaemia evokes a carotid body-mediated hyperpnoea that maintains arterial CO2 levels and prevents respiratory acidosis in the face of increased metabolism. It is unclear whether the carotid body is directly stimulated by low glucose or by a counter-regulatory hormone such as adrenaline. Minute ventilation was recorded during infusion of insulin-induced hypoglycaemia (8-17 mIU kg(-1) min(-1) ) in Alfaxan-anaesthetised male Wistar rats. Hypoglycaemia significantly augmented minute ventilation (123 ± 4 to 143 ± 7 ml min(-1) ) and CO2 sensitivity (3.3 ± 0.3 to 4.4 ± 0.4 ml min(-1) mmHg(-1) ). These effects were abolished by either β-adrenoreceptor blockade with propranolol or adrenalectomy. In this hypermetabolic, hypoglycaemic state, propranolol stimulated a rise in P aC O2, suggestive of a ventilation-metabolism mismatch. Infusion of adrenaline (1 μg kg(-1) min(-1) ) increased minute ventilation (145 ± 4 to 173 ± 5 ml min(-1) ) without altering P aC O2 or pH and enhanced ventilatory CO2 sensitivity (3.4 ± 0.4 to 5.1 ± 0.8 ml min(-1) mmHg(-1) ). These effects were attenuated by either resection of the carotid sinus nerve or propranolol. Physiological concentrations of adrenaline increased the CO2 sensitivity of freshly dissociated carotid body type I cells in vitro. These findings suggest that adrenaline release can account for the ventilatory hyperpnoea observed during hypoglycaemia by an augmented carotid body and whole body ventilatory CO2 sensitivity.
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Affiliation(s)
- Emma L Thompson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Clare J Ray
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Andrew P Holmes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Richard L Pye
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Christopher N Wyatt
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Andrew M Coney
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Prem Kumar
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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40
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Koeners MP, Lewis KE, Ford AP, Paton JF. Hypertension: a problem of organ blood flow supply-demand mismatch. Future Cardiol 2016; 12:339-49. [PMID: 27091483 PMCID: PMC4926521 DOI: 10.2217/fca.16.5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
This review introduces a new hypothesis that sympathetically mediated hypertensive diseases are caused, in the most part, by the activation of visceral afferent systems that are connected to neural circuits generating sympathetic activity. We consider how organ hypoperfusion and blood flow supply–demand mismatch might lead to both sensory hyper-reflexia and aberrant afferent tonicity. We discuss how this may drive sympatho-excitatory-positive feedback and extend across multiple organs initiating, or at least amplifying, sympathetic hyperactivity. The latter, in turn, compounds the challenge to sufficient organ blood flow through heightened vasoconstriction that both maintains and exacerbates hypertension.
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Affiliation(s)
- Maarten P Koeners
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Kirsty E Lewis
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Anthony P Ford
- Afferent Pharmaceuticals, 2929 Campus Drive, San Mateo, CA, USA
| | - Julian Fr Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
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41
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Cardiorespiratory events in preterm infants: etiology and monitoring technologies. J Perinatol 2016; 36:165-71. [PMID: 26583939 DOI: 10.1038/jp.2015.164] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/05/2015] [Indexed: 12/13/2022]
Abstract
Every year, an estimated 15 million infants are born prematurely (<37 weeks gestation) with premature birth rates ranging from 5 to 18% across 184 countries. Although there are a multitude of reasons for this high rate of preterm birth, once birth occurs, a major challenge of infant care includes the stabilization of respiration and oxygenation. Clinical care of this vulnerable infant population continues to improve, yet there are major areas that have yet to be resolved including the identification of optimal respiratory support modalities and oxygen saturation targets, and reduction of associated short- and long-term morbidities. As intermittent hypoxemia is a consequence of immature respiratory control and resultant apnea superimposed upon an immature lung, improvements in clinical care must include a thorough knowledge of premature lung development and pathophysiology that is unique to premature birth. In Part 1 of a two-part review, we summarize early lung development and diagnostic methods for cardiorespiratory monitoring.
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42
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Oxygen-sensing by arterial chemoreceptors: Mechanisms and medical translation. Mol Aspects Med 2016; 47-48:90-108. [DOI: 10.1016/j.mam.2015.12.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
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43
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López-Barneo J, González-Rodríguez P, Gao L, Fernández-Agüera MC, Pardal R, Ortega-Sáenz P. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia. Am J Physiol Cell Physiol 2016; 310:C629-42. [PMID: 26764048 DOI: 10.1152/ajpcell.00265.2015] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - M Carmen Fernández-Agüera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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44
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Andrade DC, Lucero C, Toledo C, Madrid C, Marcus NJ, Schultz HD, Del Rio R. Relevance of the Carotid Body Chemoreflex in the Progression of Heart Failure. BIOMED RESEARCH INTERNATIONAL 2015; 2015:467597. [PMID: 26779536 PMCID: PMC4686619 DOI: 10.1155/2015/467597] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/08/2015] [Indexed: 12/18/2022]
Abstract
Chronic heart failure (CHF) is a global health problem affecting millions of people. Autonomic dysfunction and disordered breathing patterns are commonly observed in patients with CHF, and both are strongly related to poor prognosis and high mortality risk. Tonic activation of carotid body (CB) chemoreceptors contributes to sympathoexcitation and disordered breathing patterns in experimental models of CHF. Recent studies show that ablation of the CB chemoreceptors improves autonomic function and breathing control in CHF and improves survival. These exciting findings indicate that alterations in CB function are critical to the progression of CHF. Therefore, better understanding of the physiology of the CB chemoreflex in CHF could lead to improvements in current treatments and clinical management of patients with CHF characterized by high chemosensitivity. Accordingly, the main focus of this brief review is to summarize current knowledge of CB chemoreflex function in different experimental models of CHF and to comment on their potential translation to treatment of human CHF.
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Affiliation(s)
- David C. Andrade
- Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, 8900000 Santiago, Chile
| | - Claudia Lucero
- Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, 8900000 Santiago, Chile
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, 8900000 Santiago, Chile
| | - Carlos Madrid
- Centro de Fisiología Celular e Integrativa, Clínica Alemana-Universidad del Desarrollo, 7500000 Santiago, Chile
| | - Noah J. Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA 50312, USA
| | - Harold D. Schultz
- Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, 8900000 Santiago, Chile
- Dirección de Investigación, Universidad Científica del Sur, Lima 15067, Peru
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45
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Carotid body oxygen sensing and adaptation to hypoxia. Pflugers Arch 2015; 468:59-70. [DOI: 10.1007/s00424-015-1734-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/01/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022]
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46
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Mansukhani MP, Wang S, Somers VK. Sleep, death, and the heart. Am J Physiol Heart Circ Physiol 2015; 309:H739-49. [PMID: 26188022 DOI: 10.1152/ajpheart.00285.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 07/13/2015] [Indexed: 12/17/2022]
Abstract
Obstructive and central sleep apnea have been associated with increased risk of adverse cardiovascular events and mortality. Sympathetic dysregulation occurring as a result of the respiratory disturbance is thought to play a role in this increased risk. Sleep apnea increases the risk of arrhythmias, myocardial ischemia/infarction, stroke, and heart failure, all of which may increase mortality risk. A higher incidence of nocturnal arrhythmias, cardiac ischemia, and sudden death has been noted in subjects with sleep-disordered breathing (SDB). In this review, the association between SDB and each of these conditions is discussed, as well as the potential mechanisms underlying these risks and the effects of treatment of SDB. Particular emphasis is placed on the relationship between SDB and nocturnal atrial and ventricular arrhythmias, myocardial ischemia/infarction and sudden death.
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Affiliation(s)
- Meghna P Mansukhani
- Sleep Medicine, Affiliated Community Medical Centers, Willmar, Minnesota; and
| | - Shihan Wang
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Virend K Somers
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
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47
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Ford AP, Undem BJ, Birder LA, Grundy D, Pijacka W, Paton JFR. P2X3 receptors and sensitization of autonomic reflexes. Auton Neurosci 2015; 191:16-24. [PMID: 25956567 DOI: 10.1016/j.autneu.2015.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A great deal of basic and applied physiology and pharmacology in sensory and autonomic neuroscience has teased apart mechanisms that drive normal perception of mechanical, thermal and chemical signals and convey them to CNS, the distinction of fiber types and receptors and channels that mediate them, and how they may become dysfunctional or maladaptive in disease. Likewise, regulation of efferent autonomic traffic to control organ reflexes has been well studied. In both afferent and efferent limbs, a wide array of potential therapeutic mechanisms has surfaced, some of which have progressed into clinic, if not full regrastration. One conversation that has been less well progressed relates to how the afferent limb and its sensitization shapes the efferent outputs, and where modulation may offer new therapeutic avenues, especially for poorly addressed and common signs and symptoms of disease. Therapeutics for CV disease (HF, hypertension), respiratory disease (asthma, COPD), urological disease (OAB), GI disease (IBS), and inter alia, have largely focused on the efferent control of effector cells to modulate movement, contraction and secretion; medicinal needs remain with limits to efficacy, AEs and treatment resistance being common. We now must turn, in the quest for improved therapeutics, to understand how sensation from these organs becomes maladapted and sensitized in disease, and what opportunities may arise for improved therapeutics given the abundance of targets, many pharmacologically untapped, on the afferent side. One might look at the treatment resistant hypertension and the emerging benefit of renal denervation; or urinary bladder overactivity / neurogenic bladder and the emergence of neuromodulation, capsaicin instillation or botox injections to attenuate sensitized reflexes, as examples of merely the start of such progress. This review examines this topic more deeply, as applies to four major organ systems all sharing a great need from unsatisfied patients.
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Affiliation(s)
| | - Bradley J Undem
- Johns Hopkins School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, MD 21224, USA
| | - Lori A Birder
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburg, PA 15261, USA
| | - David Grundy
- Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
| | - Wioletta Pijacka
- School of Physiology & Pharmacology, Bristol CardioVascular, University of Bristol, Bristol, BS8 1TD, UK
| | - Julian F R Paton
- School of Physiology & Pharmacology, Bristol CardioVascular, University of Bristol, Bristol, BS8 1TD, UK
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48
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Abstract
In conscious mammals, hypoxia or hypercapnia stimulates breathing while theoretically exerting opposite effects on central respiratory chemoreceptors (CRCs). We tested this theory by examining how hypoxia and hypercapnia change the activity of the retrotrapezoid nucleus (RTN), a putative CRC and chemoreflex integrator. Archaerhodopsin-(Arch)-transduced RTN neurons were reversibly silenced by light in anesthetized rats. We bilaterally transduced RTN and nearby C1 neurons with Arch (PRSx8-ArchT-EYFP-LVV) and measured the cardiorespiratory consequences of Arch activation (10 s) in conscious rats during normoxia, hypoxia, or hyperoxia. RTN photoinhibition reduced breathing equally during non-REM sleep and quiet wake. Compared with normoxia, the breathing frequency reduction (Δf(R)) was larger in hyperoxia (65% FiO2), smaller in 15% FiO2, and absent in 12% FiO2. Tidal volume changes (ΔV(T)) followed the same trend. The effect of hypoxia on Δf(R) was not arousal-dependent but was reversed by reacidifying the blood (acetazolamide; 3% FiCO2). Δf(R) was highly correlated with arterial pH up to arterial pH (pHa) 7.5 with no frequency inhibition occurring above pHa 7.53. Blood pressure was minimally reduced suggesting that C1 neurons were very modestly inhibited. In conclusion, RTN neurons regulate eupneic breathing about equally during both sleep and wake. RTN neurons are the first putative CRCs demonstrably silenced by hypocapnic hypoxia in conscious mammals. RTN neurons are silent above pHa 7.5 and increasingly active below this value. During hyperoxia, RTN activation maintains breathing despite the inactivity of the carotid bodies. Finally, during hypocapnic hypoxia, carotid body stimulation increases breathing frequency via pathways that bypass RTN.
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49
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Jaźwiec P, Gać P, Jurdziak M, Poręba M, Mazur G, Sobieszczańska M, Poręba R. Volume of carotid bodies and cardiac autonomic function in patients with essential hypertension. Auton Neurosci 2015; 190:26-32. [PMID: 25817902 DOI: 10.1016/j.autneu.2015.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/30/2015] [Accepted: 03/09/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE Determination of the relationship between the estimated total volume of the carotid bodies (VrCB+lCB), assessed by computed tomography angiography (CTA), and the autonomic cardiac function in patients with essential hypertension (EH). MATERIALS AND METHODS The study included 69 patients with diagnosed and pharmacologically treated EH. The estimated volume of each carotid body (CB) was evaluated on the basis of scans obtained in the CTA of carotid arteries, using the following formula: 4/3×π×half of transverse dimension of CB in axial projection×half of longitudinal dimension of CB in the axial projection×half of craniocaudal dimension of CB in the sagittal/coronal projection. Cardiac autonomic function was assessed using time domain analysis of heart rate variability (HRV). RESULTS The mean values of SDNNi, rMSSD and pNN50 at 24-h monitoring, during daily activity and during night rest, were significantly lower in patients with hypertension with the values of VrCB+lCB≥median compared to the group of hypertensive patients with the values of VrCB+lCB<median. Moreover, in patients with EH with the values of VrCB+lCB≥median, the mean values of SDNN were lower during daily activity. Based on the regression analysis, it was found out that the higher values of VrCB+lCB are an independent risk factor in HRV reduction (expressed as a reduction in the rMSSD). CONCLUSION In patients with EH, a relationship between the volume of CB, assessed by CTA of carotid arteries, and autonomic cardiac function seems to be probable.
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Affiliation(s)
- Przemysław Jaźwiec
- Department of Radiology and Diagnostic Imaging, 4th Military Hospital, Weigla 5, Wroclaw PL 50-981, Poland.
| | - Paweł Gać
- Department of Radiology and Diagnostic Imaging, 4th Military Hospital, Weigla 5, Wroclaw PL 50-981, Poland
| | - Marta Jurdziak
- Department of Internal Medicine, Occupational Diseases and Hypertension, Wroclaw Medical University, Borowska 213, Wroclaw PL 50-556, Poland
| | - Małgorzata Poręba
- Department of Pathophysiology, Wroclaw Medical University, Marcinkowskiego 1, Wroclaw PL 50-368, Poland
| | - Grzegorz Mazur
- Department of Internal Medicine, Occupational Diseases and Hypertension, Wroclaw Medical University, Borowska 213, Wroclaw PL 50-556, Poland
| | - Małgorzata Sobieszczańska
- Department of Pathophysiology, Wroclaw Medical University, Marcinkowskiego 1, Wroclaw PL 50-368, Poland
| | - Rafał Poręba
- Department of Internal Medicine, Occupational Diseases and Hypertension, Wroclaw Medical University, Borowska 213, Wroclaw PL 50-556, Poland
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Schultz HD, Marcus NJ, Del Rio R. Mechanisms of carotid body chemoreflex dysfunction during heart failure. Exp Physiol 2015; 100:124-9. [PMID: 25398713 DOI: 10.1113/expphysiol.2014.079517] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/03/2014] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? Carotid body chemoreceptor activity is tonically elevated in heart failure and contributes to morbidity due to the reflex activation of sympathetic nerve activity and destabilization of breathing. The potential causes for the enhanced chemoreceptor activation in heart failure are discussed. What advances does it highlight? The role of a chronic reduction in blood flow to the carotid body due to cardiac failure and its impact on signalling pathways in the carotid body is discussed. Recent advances have attracted interest in the potential for carotid body (CB) ablation or desensitization as an effective strategy for clinical treatment and management of cardiorespiratory diseases, including hypertension, heart failure, diabetes mellitus, metabolic syndrome and renal failure. These disease states have in common sympathetic overactivity, which plays an important role in the development and progression of the disease and is often associated with breathing dysregulation, which in turn is likely to mediate or aggravate the autonomic imbalance. Evidence from both chronic heart failure (CHF) patients and animal models indicates that the CB chemoreflex is enhanced in CHF and contributes to the tonic elevation in sympathetic activity and the development of periodic breathing associated with the disease. Although this maladaptive change is likely to derive from altered function at all levels of the reflex arc, a tonic increase in afferent activity from CB glomus cells is likely to be a main driving force. This report focuses on our understanding of mechanisms that alter CB function in CHF and their potential translational impact on treatment of CHF.
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Affiliation(s)
- Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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