101
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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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102
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Neuzil P, Merkely B, Erglis A, Marinskis G, de Groot JR, Schmidinger H, Rodriguez Venegas M, Voskuil M, Sturmberger T, Petru J, Jongejan N, Aichinger J, Kamzola G, Aidietis A, Gellér L, Mraz T, Osztheimer I, Mika Y, Evans S, Burkhoff D, Kuck KH. Pacemaker-Mediated Programmable Hypertension Control Therapy. J Am Heart Assoc 2017; 6:JAHA.117.006974. [PMID: 29275370 PMCID: PMC5779015 DOI: 10.1161/jaha.117.006974] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Background Many patients requiring a pacemaker have persistent hypertension with systolic blood pressures above recommended levels. We evaluated a pacemaker‐based Programmable Hypertension Control (PHC) therapy that uses a sequence of variably timed shorter and longer atrioventricular intervals. Methods and Results Patients indicated for dual‐chamber pacing with office systolic blood pressure (oSBP) >150 mm Hg despite stable medical therapy were implanted with a Moderato™ pulse generator that delivers PHC therapy. Patients were followed for 1 month (Run‐In period) with conventional pacing; those with persistent oSBP >140 mm Hg were included in the study and had PHC therapy activated. The co‐primary efficacy end points were changes in 24‐hour ambulatory systolic blood pressure and oSBP between baseline and 3 months. Safety was assessed by tracking adverse events. Thirty‐five patients met the initial inclusion criteria and underwent Moderato implantation. At 1 month, oSBP was <140 mm Hg in 7 patients who were excluded. PHC was activated in the remaining 27 patients with baseline office blood pressure 166±11/80±10 mm Hg despite an average of 3.2 antihypertensive medications. During the Run‐In period, oSBP and 24‐hour ambulatory systolic blood pressure decreased by 8±13 and 5±12 mm Hg (P<0.002), respectively. Compared with pre‐PHC activation measurements, oSBP decreased by another 16±15 mm Hg and 24‐hour ambulatory systolic blood pressure decreased by an additional 10±13 mm Hg (both P<0.01) at 3 months. No device‐related serious adverse effects were noted. Conclusions In pacemaker patients with persistent hypertension despite medical therapy, oSBP and 24‐hour ambulatory systolic blood pressure are decreased by PHC therapy. Initial indications are that this therapy is a safe and promising therapy for such patients. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02282033.
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Affiliation(s)
| | - Béla Merkely
- Heart and Vascular Center, Semmelweis University Budapest, Budapest, Hungary
| | - Andrejs Erglis
- Latvian Centre of Cardiology, Pauls Stradins Clinical University Hospital, Riga, Latvia
| | | | - Joris R de Groot
- Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Herwig Schmidinger
- Abteilung für Kardiologie, AKH - Universitätsklinik für Innere Medizin II, Vienna, Austria.,Sigmund Freud Private University of Vienna, Austria
| | | | - Michiel Voskuil
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Thomas Sturmberger
- Interne 2 - Kardiologie, Angiologie & Interne Intensivmedizin, Krankenhaus der Elisabethinen Linz GmbH, Linz, Austria
| | - Jan Petru
- Na Homolce Hospital, Prague, Czech Republic
| | - Niels Jongejan
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Josef Aichinger
- Interne 2 - Kardiologie, Angiologie & Interne Intensivmedizin, Krankenhaus der Elisabethinen Linz GmbH, Linz, Austria
| | - Ginta Kamzola
- Latvian Centre of Cardiology, Pauls Stradins Clinical University Hospital, Riga, Latvia
| | - Audrius Aidietis
- Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania
| | - Laszlo Gellér
- Heart and Vascular Center, Semmelweis University Budapest, Budapest, Hungary
| | - Tomas Mraz
- Na Homolce Hospital, Prague, Czech Republic
| | - Istvan Osztheimer
- Heart and Vascular Center, Semmelweis University Budapest, Budapest, Hungary
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103
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Conde SV, Monteiro EC, Sacramento JF. Purines and Carotid Body: New Roles in Pathological Conditions. Front Pharmacol 2017; 8:913. [PMID: 29311923 PMCID: PMC5733106 DOI: 10.3389/fphar.2017.00913] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/29/2017] [Indexed: 01/28/2023] Open
Abstract
It is known that adenosine and adenosine-5′-triphosphate (ATP) are excitatory mediators involved in carotid body (CB) hypoxic signaling. The CBs are peripheral chemoreceptors classically defined by O2, CO2, and pH sensors. When hypoxia activates the CB, it induces the release of neurotransmitters from chemoreceptor cells leading to an increase in the action potentials frequency at the carotid sinus nerve (CSN). This increase in the firing frequency of the CSN is integrated in the brainstem to induce cardiorespiratory compensatory responses. In the last decade several pathologies, as, hypertension, diabetes, obstructive sleep apnea and heart failure have been associated with CB overactivation. In the first section of the present manuscript we review in a concise manner fundamental aspects of purine metabolism. The second section is devoted to the role of purines on the hypoxic response of the CB, providing the state-of-the art for the presence of adenosine and ATP receptors in the CB; for the role of purines at presynaptic level in CB chemoreceptor cells, as well as, its metabolism and regulation; at postsynaptic level in the CSN activity; and on the ventilatory responses to hypoxia. Recently, we have showed that adenosine is involved in CB hypersensitization during chronic intermittent hypoxia (CIH), which mimics obstructive sleep apnea, since caffeine, a non-selective adenosine receptor antagonist that inhibits A2A and A2B adenosine receptors, decreased CSN chemosensory activity in animals subjected to CIH. Apart from this involvement of adenosine in CB sensitization in sleep apnea, it was recently found that P2X3 ATP receptor in the CB contributes to increased chemoreflex hypersensitivity and hypertension in spontaneously hypertension rats. Therefore the last section of this manuscript is devoted to review the recent findings on the role of purines in CB-mediated pathologies as hypertension, diabetes and sleep apnea emphasizing the potential clinical importance of modulating purines levels and action to treat pathologies associated with CB dysfunction.
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Affiliation(s)
- Silvia V Conde
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Emilia C Monteiro
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Joana F Sacramento
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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104
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Abboud FM, Singh MV. Autonomic regulation of the immune system in cardiovascular diseases. ADVANCES IN PHYSIOLOGY EDUCATION 2017; 41:578-593. [PMID: 29138216 PMCID: PMC6105770 DOI: 10.1152/advan.00061.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/26/2017] [Accepted: 09/26/2017] [Indexed: 05/27/2023]
Abstract
The autonomic nervous system is a powerful regulator of circulatory adjustments to acute hemodynamic stresses. Here we focus on new concepts that emphasize the chronic influence of the sympathetic and parasympathetic systems on cardiovascular pathology. The autonomic neurohumoral system can dramatically influence morbidity and mortality from cardiovascular disease through newly discovered influences on the innate and adaptive immune systems. Specifically, the end-organ damage in heart failure or hypertension may be worsened or alleviated by pro- or anti-inflammatory pathways of the immune system, respectively, that are activated through neurohumoral transmitters. These concepts provide a major new perspective on potentially life-saving therapeutic interventions in the deadliest of diseases.
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Affiliation(s)
- François M Abboud
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Madhu V Singh
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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105
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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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106
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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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107
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Marcus NJ, Del Rio R, Ding Y, Schultz HD. KLF2 mediates enhanced chemoreflex sensitivity, disordered breathing and autonomic dysregulation in heart failure. J Physiol 2017; 596:3171-3185. [PMID: 29023738 DOI: 10.1113/jp273805] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 08/31/2017] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Enhanced carotid body chemoreflex activity contributes to development of disordered breathing patterns, autonomic dysregulation and increases in incidence of arrhythmia in animal models of reduced ejection fraction heart failure. Chronic reductions in carotid artery blood flow are associated with increased carotid body chemoreceptor activity. Krüppel-like Factor 2 (KLF2) is a shear stress-sensitive transcription factor that regulates the expression of enzymes which have previously been shown to play a role in increased chemoreflex sensitivity. We investigated the impact of restoring carotid body KLF2 expression on chemoreflex control of ventilation, sympathetic nerve activity, cardiac sympatho-vagal balance and arrhythmia incidence in an animal model of heart failure. The results indicate that restoring carotid body KLF2 in chronic heart failure reduces sympathetic nerve activity and arrhythmia incidence, and improves cardiac sympatho-vagal balance and breathing stability. Therapeutic approaches that increase KLF2 in the carotid bodies may be efficacious in the treatment of respiratory and autonomic dysfunction in heart failure. ABSTRACT Oscillatory breathing and increased sympathetic nerve activity (SNA) are associated with increased arrhythmia incidence and contribute to mortality in chronic heart failure (CHF). Increased carotid body chemoreflex (CBC) sensitivity plays a role in this process and can be precipitated by chronic blood flow reduction. We hypothesized that downregulation of a shear stress-sensitive transcription factor, Krüppel-like Factor 2 (KLF2), mediates increased CBC sensitivity in CHF and contributes to associated autonomic, respiratory and cardiac sequelae. Ventilation (Ve), renal SNA (RSNA) and ECG were measured at rest and during CBC activation in sham and CHF rabbits. Oscillatory breathing was quantified as the apnoea-hypopnoea index (AHI) and respiratory rate variability index (RRVI). AHI (control 6 ± 1/h, CHF 25 ± 1/h), RRVI (control 9 ± 3/h, CHF 29 ± 3/h), RSNA (control 22 ± 2% max, CHF 43 ± 5% max) and arrhythmia incidence (control 50 ± 10/h, CHF 300 ± 100/h) were increased in CHF at rest ( FIO2 21%), as were CBC responses (Ve, RSNA) to 10% FIO2 (all P < 0.05 vs. control). In vivo adenoviral transfection of KLF2 to the carotid bodies in CHF rabbits restored KLF2 expression, and reduced AHI (7 ± 2/h), RSNA (18 ± 2% max) and arrhythmia incidence (46 ± 13/h) as well as CBC responses to hypoxia (all P < 0.05 vs. CHF empty virus). Conversely, lentiviral KLF2 siRNA in the carotid body decreased KLF2 expression, increased chemoreflex sensitivity, and increased AHI (6 ± 2/h vs. 14 ± 3/h), RRVI (5 ± 3/h vs. 20 ± 3/h) and RSNA (24 ± 4% max vs. 34 ± 5% max) relative to scrambled-siRNA rabbits. In conclusion, down-regulation of KLF2 in the carotid body increases CBC sensitivity, oscillatory breathing, RSNA and arrhythmia incidence during CHF.
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Affiliation(s)
- Noah J Marcus
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.,Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA, USA
| | - Rodrigo Del Rio
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.,Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Yanfeng Ding
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.,University of North Texas Health Sciences Center, Fort Worth, TX, USA
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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108
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Patinha D, Pijacka W, Paton JFR, Koeners MP. Cooperative Oxygen Sensing by the Kidney and Carotid Body in Blood Pressure Control. Front Physiol 2017; 8:752. [PMID: 29046642 PMCID: PMC5632678 DOI: 10.3389/fphys.2017.00752] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/15/2017] [Indexed: 12/13/2022] Open
Abstract
Oxygen sensing mechanisms are vital for homeostasis and survival. When oxygen levels are too low (hypoxia), blood flow has to be increased, metabolism reduced, or a combination of both, to counteract tissue damage. These adjustments are regulated by local, humoral, or neural reflex mechanisms. The kidney and the carotid body are both directly sensitive to falls in the partial pressure of oxygen and trigger reflex adjustments and thus act as oxygen sensors. We hypothesize a cooperative oxygen sensing function by both the kidney and carotid body to ensure maintenance of whole body blood flow and tissue oxygen homeostasis. Under pathological conditions of severe or prolonged tissue hypoxia, these sensors may become continuously excessively activated and increase perfusion pressure chronically. Consequently, persistence of their activity could become a driver for the development of hypertension and cardiovascular disease. Hypoxia-mediated renal and carotid body afferent signaling triggers unrestrained activation of the renin angiotensin-aldosterone system (RAAS). Renal and carotid body mediated responses in arterial pressure appear to be synergistic as interruption of either afferent source has a summative effect of reducing blood pressure in renovascular hypertension. We discuss that this cooperative oxygen sensing system can activate/sensitize their own afferent transduction mechanisms via interactions between the RAAS, hypoxia inducible factor and erythropoiesis pathways. This joint mechanism supports our view point that the development of cardiovascular disease involves afferent nerve activation.
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Affiliation(s)
- Daniela Patinha
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Wioletta Pijacka
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Maarten P Koeners
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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109
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Bock JM, Ueda K, Schneider AC, Hughes WE, Limberg JK, Bryan NS, Casey DP. Inorganic nitrate supplementation attenuates peripheral chemoreflex sensitivity but does not improve cardiovagal baroreflex sensitivity in older adults. Am J Physiol Heart Circ Physiol 2017; 314:H45-H51. [PMID: 28971842 DOI: 10.1152/ajpheart.00389.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aging is associated with increased peripheral chemoreceptor activity, reduced nitric oxide (NO) bioavailability, and attenuation of cardiovagal baroreflex sensitivity (BRS), collectively increasing the risk of cardiovascular disease. Evidence suggests that NO may attenuate peripheral chemoreflex sensitivity and increase BRS. Exogenous inorganic nitrate ([Formula: see text]) increases NO bioavailability via the [Formula: see text]-[Formula: see text]-NO pathway. Our hypothesis was that inorganic [Formula: see text] supplementation would attenuate peripheral chemoreflex sensitivity and enhance spontaneous cardiovagal BRS in older adults. We used a randomized, placebo-controlled crossover design in which 13 older (67 ± 3 yr old) adults ingested beetroot powder containing (BRA) or devoid of (BRP) [Formula: see text] and [Formula: see text] daily over 4 wk. Spontaneous cardiovagal BRS was assessed over 15 min of rest and was quantified using the sequence method. Chemoreflex sensitivity was assessed via ~5 min of hypoxia (10% fraction of inspired O2) and reported as the slope of the relationship between O2 saturation (%[Formula: see text]) and minute ventilation (in l/min) or heart rate (in beats/min). Ventilatory responsiveness to hypoxia was reduced after BRA (from -0.14 ± 0.04 to -0.05 ± 0.02 l·min-1·%[Formula: see text]-1, P = 0.01) versus BRP (from -0.10 ± 0.05 to -0.11 ± 0.05 l·min-1·%[Formula: see text]-1, P = 0.80), with no differences in heart rate responsiveness (BRA: from -0.47 ± 0.06 to -0.33 ± 0.04 beats·min-1·%[Formula: see text]-1, BRP: from -0.48 ± 0.07 to -0.42 ± 0.06 beats·min-1·%[Formula: see text]-1) between conditions (interaction effect, P = 0.41). Spontaneous cardiovagal BRS was unchanged after BRA and BRP (interaction effects, P = 0.69, 0.94, and 0.39 for all, up, and down sequences, respectively), despite a reduction in resting systolic and mean arterial blood pressure in the experimental (BRA) group ( P < 0.01 for both). These findings illustrate that inorganic [Formula: see text] supplementation attenuates peripheral chemoreflex sensitivity without concomitant change in spontaneous cardiovagal BRS in older adults. NEW & NOTEWORTHY Exogenous inorganic nitrate supplementation attenuates ventilatory, but not heart rate, responsiveness to abbreviated hypoxic exposure in older adults. Additionally, inorganic nitrate reduces systolic and mean arterial blood pressure without affecting spontaneous cardiovagal baroreflex sensitivity. These findings suggest that inorganic nitrate may attenuate sympathetically oriented pathologies associated with aging.
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Affiliation(s)
- Joshua M Bock
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Kenichi Ueda
- Department of Anesthesia, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Aaron C Schneider
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - William E Hughes
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | | | - Nathan S Bryan
- Department of Molecular and Human Genetics, Baylor College of Medicine , Houston, Texas
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa , Iowa City, Iowa.,Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa , Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa , Iowa City, Iowa
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110
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McCallum GA, Sui X, Qiu C, Marmerstein J, Zheng Y, Eggers TE, Hu C, Dai L, Durand DM. Chronic interfacing with the autonomic nervous system using carbon nanotube (CNT) yarn electrodes. Sci Rep 2017; 7:11723. [PMID: 28916761 PMCID: PMC5601469 DOI: 10.1038/s41598-017-10639-w] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 08/10/2017] [Indexed: 11/23/2022] Open
Abstract
The ability to reliably and safely communicate chronically with small diameter (100–300 µm) autonomic nerves could have a significant impact in fundamental biomedical research and clinical applications. However, this ability has remained elusive with existing neural interface technologies. Here we show a new chronic nerve interface using highly flexible materials with axon-like dimensions. The interface was implemented with carbon nanotube (CNT) yarn electrodes to chronically record neural activity from two separate autonomic nerves: the glossopharyngeal and vagus nerves. The recorded neural signals maintain a high signal-to-noise ratio (>10 dB) in chronic implant models. We further demonstrate the ability to process the neural activity to detect hypoxic and gastric extension events from the glossopharyngeal and vagus nerves, respectively. These results establish a novel, chronic platform neural interfacing technique with the autonomic nervous system and demonstrate the possibility of regulating internal organ function, leading to new bioelectronic therapies and patient health monitoring.
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Affiliation(s)
- Grant A McCallum
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Xiaohong Sui
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Chen Qiu
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Joseph Marmerstein
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Yang Zheng
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Thomas E Eggers
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Chuangang Hu
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Liming Dai
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA
| | - Dominique M Durand
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA.
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111
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Saku K, Tohyama T, Shinoda M, Kishi T, Hosokawa K, Nishikawa T, Oga Y, Sakamoto T, Tsutsui H, Miyamoto T, Sunagawa K. Central chemoreflex activation induces sympatho-excitation without altering static or dynamic baroreflex function in normal rats. Physiol Rep 2017; 5:5/17/e13406. [PMID: 28899913 PMCID: PMC5599864 DOI: 10.14814/phy2.13406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/07/2017] [Indexed: 11/24/2022] Open
Abstract
Central chemoreflex activation induces sympatho-excitation. However, how central chemoreflex interacts with baroreflex function remains unknown. This study aimed to examine the impact of central chemoreflex on the dynamic as well as static baroreflex functions under open-loop conditions. In 15 anesthetized, vagotomized Sprague-Dawley rats, we isolated bilateral carotid sinuses and controlled intra-sinus pressure (CSP). We then recorded sympathetic nerve activity (SNA) at the celiac ganglia, and activated central chemoreflex by a gas mixture containing various concentrations of CO2 Under the baroreflex open-loop condition (CSP = 100 mmHg), central chemoreflex activation linearly increased SNA and arterial pressure (AP). To examine the static baroreflex function, we increased CSP stepwise from 60 to 170 mmHg and measured steady-state SNA responses to CSP (mechanoneural arc), and AP responses to SNA (neuromechanical arc). Central chemoreflex activation by inhaling 3% CO2 significantly increased SNA irrespective of CSP, indicating resetting of the mechanoneural arc, but did not change the neuromechanical arc. As a result, central chemoreflex activation did not change baroreflex maximum total loop gain significantly (-1.29 ± 0.27 vs. -1.68 ± 0.74, N.S.). To examine the dynamic baroreflex function, we randomly perturbed CSP and estimated transfer functions from 0.01 to 1.0 Hz. The transfer function of the mechanoneural arc approximated a high-pass filter, while those of the neuromechanical arc and total (CSP-AP relationship) arcs approximated a low-pass filter. In conclusion, central chemoreflex activation did not alter the transfer function of the mechanoneural, neuromechanical, or total arcs. Central chemoreflex modifies hemodynamics via sympatho-excitation without compromising dynamic or static baroreflex AP buffering function.
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Affiliation(s)
- Keita Saku
- Department of Advanced Risk Stratification for Cardiovascular Diseases, Center for Disruptive Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - Takeshi Tohyama
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masako Shinoda
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takuya Kishi
- Department of Advanced Risk Stratification for Cardiovascular Diseases, Center for Disruptive Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - Kazuya Hosokawa
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takuya Nishikawa
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuhiro Oga
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takafumi Sakamoto
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Tsutsui
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tadayoshi Miyamoto
- Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka, Japan
| | - Kenji Sunagawa
- Department of Therapeutic Regulation of Cardiovascular Homeostasis, Center for Disruptive Cardiovascular Medicine Kyushu University, Fukuoka, Japan
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Visualizing Carotid Bodies With Doppler Ultrasound Versus CT Angiography: Preliminary Study. AJR Am J Roentgenol 2017; 209:1348-1352. [PMID: 28871807 DOI: 10.2214/ajr.17.18079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this article is to evaluate the utility of ultrasound in identifying carotid bodies (CBs) in patients with drug-resistant arterial hypertension. SUBJECTS AND METHODS We enrolled 13 patients with drug-resistant hypertension into a trial for surgical CB excision. CT angiography (CTA) and Doppler ultrasound (DUS) of the cervical arteries were performed before surgery. CBs were identified in a blind manner at both CTA and DUS. CBs were defined at CTA as ovoid avidly enhancing structures at the inferomedial aspect of the carotid bifurcation. At DUS, CBs were defined as ovoid solid structures in the inferomedial aspect of the bifurcation. RESULTS CBs were identified in 12 of 13 patients (23/26 sides) using CTA and in 11 of 13 patients (18/26 sides) using DUS. Identification of CB with DUS and CTA correlated in 17 of 18 cases; in one instance, CB was identified with DUS but not CTA. There was no statistically significant difference in size and volume of CB measured by both methods. CONCLUSION Noncarcinogenic CBs can be visualized using DUS, with good correlation of size and location compared with CTA. The findings show that DUS can be reliably used to further examine the role of CBs in cardiovascular disorders and can be used in conjunction with therapies that target CBs.
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113
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Salavatian S, Beaumont E, Gibbons D, Hammer M, Hoover DB, Armour JA, Ardell JL. Thoracic spinal cord and cervical vagosympathetic neuromodulation obtund nodose sensory transduction of myocardial ischemia. Auton Neurosci 2017; 208:57-65. [PMID: 28919363 DOI: 10.1016/j.autneu.2017.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/07/2017] [Accepted: 08/16/2017] [Indexed: 12/01/2022]
Abstract
BACKGROUND Autonomic regulation therapy involving either vagus nerve stimulation (VNS) or spinal cord stimulation (SCS) represents emerging bioelectronic therapies for heart disease. The objective of this study was to determine if VNS and/or SCS modulate primary cardiac afferent sensory transduction of the ischemic myocardium. METHODS Using extracellular recordings in 19 anesthetized canines, of 88 neurons evaluated, 36 ventricular-related nodose ganglia sensory neurons were identified by their functional activity responses to epicardial touch, chemical activation of their sensory neurites (epicardial veratridine) and great vessel (descending aorta or inferior vena cava) occlusion. Neural responses to 1min left anterior descending (LAD) coronary artery occlusion (CAO) were then evaluated. These interventions were then studied following either: i) SCS [T1-T3 spinal level; 50Hz, 90% motor threshold] or ii) cervical VNS [15-20Hz; 1.2× threshold]. RESULTS LAD occlusion activated 66% of identified nodose ventricular sensory neurons (0.33±0.08-0.79±0.20Hz; baseline to CAO; p<0.002). Basal activity of cardiac-related nodose neurons was differentially reduced by VNS (0.31±0.11 to 0.05±0.02Hz; p<0.05) as compared to SCS (0.36±0.12 to 0.28±0.14, p=0.59), with their activity response to transient LAD CAO being suppressed by either SCS (0.85±0.39-0.11±0.04Hz; p<0.03) or VNS (0.75±0.27-0.12±0.05Hz; p<0.04). VNS did not alter evoked neural responses of cardiac-related nodose neurons to great vessel occlusion. CONCLUSIONS Both VNS and SCS obtund ventricular ischemia induced enhancement of nodose afferent neuronal inputs to the medulla.
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Affiliation(s)
- Siamak Salavatian
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States; UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States
| | - Eric Beaumont
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, TN, United States; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, United States
| | - David Gibbons
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Matthew Hammer
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States
| | - Donald B Hoover
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, TN, United States; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, United States
| | - J Andrew Armour
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States; UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States
| | - Jeffrey L Ardell
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States; UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States.
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114
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Abstract
Hypertension continues to be a major contributor to global morbidity and mortality, fuelled by an abundance of patients with uncontrolled blood pressure despite the multitude of pharmacological options available. This may occur as a consequence of true resistant hypertension, through an inability to tolerate current pharmacological therapies, or non-adherence to antihypertensive medication. In recent years, there has been a rapid expansion of device-based therapies proposed as novel non-pharmacological approaches to treating resistant hypertension. In this review, we discuss seven novel devices—renal nerve denervation, baroreflex activation therapy, carotid body ablation, central iliac arteriovenous anastomosis, deep brain stimulation, median nerve stimulation, and vagal nerve stimulation. We highlight how the devices differ, the varying degrees of evidence available to date and upcoming trials. This review also considers the possible factors that may enable appropriate device selection for different hypertension phenotypes.
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Affiliation(s)
- Fu L Ng
- Barts BP Centre of Excellence, Barts Heart Centre, St Bartholomew's Hospital, W Smithfield, London, EC1A 7BE, UK.,Barts NIHR Cardiovascular Biomedical Research Unit, Charterhouse Square, William Harvey Research Institute, Queen Mary University London, London, EC1M 6BQ, UK
| | - Manish Saxena
- Barts BP Centre of Excellence, Barts Heart Centre, St Bartholomew's Hospital, W Smithfield, London, EC1A 7BE, UK.,Barts NIHR Cardiovascular Biomedical Research Unit, Charterhouse Square, William Harvey Research Institute, Queen Mary University London, London, EC1M 6BQ, UK
| | - Felix Mahfoud
- Department of Internal Medicine, Cardiology, Angiology, Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
| | - Atul Pathak
- Department of Cardiovascular Medicine, Hypertension and Heart Failure Unit, Health Innovation Lab (Hi-Lab) Clinique Pasteur, Toulouse, France
| | - Melvin D Lobo
- Barts BP Centre of Excellence, Barts Heart Centre, St Bartholomew's Hospital, W Smithfield, London, EC1A 7BE, UK. .,Barts NIHR Cardiovascular Biomedical Research Unit, Charterhouse Square, William Harvey Research Institute, Queen Mary University London, London, EC1M 6BQ, UK.
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115
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Lachowska K, Gruchała M, Narkiewicz K, Hering D. Sympathetic Activation in Chronic Heart Failure: Potential Benefits of Interventional Therapies. Curr Hypertens Rep 2017; 18:51. [PMID: 27193773 DOI: 10.1007/s11906-016-0660-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Heart failure (HF) is a major and growing public health problem. This condition is associated with poor prognosis, a high rate of mortality, frequent hospitalization and increasing costs to health care systems. Pharmacological approaches aimed at reducing morbidity and mortality in HF have primarily focused on inhibition of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system (SNS), both of which have been associated with disease development, progression and adverse cardiovascular (CV) outcomes. The increasing number of hospitalizations for HF decompensation suggests the failure of available treatment options, indicating the necessity for alternative therapeutic approaches. Alongside pharmacological and cardiac resynchronization therapies in selected patients with arrhythmia, recent advancements in the management of HF have been directed at inhibiting relevant neurogenic pathways underlying disease development and progression. Initial evidence regarding the safety and effectiveness of interventional procedures suggests that HF patients may benefit from novel adjunctive therapies. Here we review the critical role of sympathetic activation in HF and the rationale for therapeutic interventions including device-based and interventional approaches aimed at restoring autonomic neural balance in this condition.
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Affiliation(s)
- Kamila Lachowska
- First Department of Cardiology, Medical University of Gdansk, Gdansk, Poland
| | - Marcin Gruchała
- First Department of Cardiology, Medical University of Gdansk, Gdansk, Poland
| | - Krzysztof Narkiewicz
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Dagmara Hering
- Dobney Hypertension Centre, School of Medicine and Pharmacology-Royal Perth Hospital Unit, The University of Western Australia, Level 3 MRF Building, Rear 50 Murray Street, Perth, WA, 6000, MDBP: M570, Australia.
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116
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Fujii K, Saku K, Kishi T, Oga Y, Tohyama T, Nishikawa T, Sakamoto T, Ikeda M, Ide T, Tsutsui H, Sunagawa K. Carotid Body Denervation Markedly Improves Survival in Rats With Hypertensive Heart Failure. Am J Hypertens 2017; 30:791-798. [PMID: 28430843 DOI: 10.1093/ajh/hpx062] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 03/24/2017] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Hypertension is a major cause of heart failure. Excessive sympathoexcitation in patients with heart failure leads to poor prognosis. Since carotid body denervation (CBD) has been shown to reduce sympathetic nerve activity in animal models of hypertension and heart failure, we examined if bilateral CBD attenuates the progression of hypertensive heart failure and improves survival. METHODS We randomly allocated Dahl salt-sensitive rats fed a high-salt diet from 6 weeks of age into CBD (n = 31) and sham-operation (SHAM; n = 50) groups, and conducted CBD or SHAM at 7 weeks of age. We examined the time course of 24-hour urinary norepinephrine (uNE) excretion, blood pressure (BP) and the percent fractional shortening assessed by echocardiography, and estimated the pressure-natriuresis relationship at 14 weeks of age. Finally, we assessed hemodynamics, histological findings, and survival at 16 weeks of age. RESULTS Compared to SHAM, CBD significantly reduced 24-hour uNE at 12, 14, and 16 weeks of age, shifted the pressure-natriuresis relationship leftward without changing its slope, and attenuated the increase in BP. CBD preserved percent fractional shortening (34.2 ± 1.2 vs. 29.1 ± 1.3%, P < 0.01) and lowered left ventricular end-diastolic pressure (5.0 ± 0.9 vs. 9.0 ± 1.4 mm Hg, P < 0.05). Furthermore, CBD significantly attenuated myocardial hypertrophy (P < 0.01) and fibrosis (P < 0.01). Consequently, CBD markedly improved survival (relative risk reduction: 64.8%). CONCLUSIONS CBD attenuated the progression of hypertension and worsening of heart failure possibly through sympathoinhibition, and markedly improved survival in a rat model of hypertensive heart failure.
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Affiliation(s)
- Kana Fujii
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Keita Saku
- Department of Therapeutic Regulation of Cardiovascular Homeostasis, Center for Disruptive Cardiovascular Medicine, Kyushu University, Maidashi Higashi-ku, Fukuoka, Japan
| | - Takuya Kishi
- Collaborative Research Institute of Innovative Therapeutics for Cardiovascular Diseases, Center for Disruptive Cardiovascular Medicine, Kyushu University, Maidashi Higashi-ku, Fukuoka, Japan
| | - Yasuhiro Oga
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Takeshi Tohyama
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Takuya Nishikawa
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Takafumi Sakamoto
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Masataka Ikeda
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Tomomi Ide
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Hiroyuki Tsutsui
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University,Maidashi, Higashi-ku, Fukuoka, Japan
| | - Kenji Sunagawa
- Department of Therapeutic Regulation of Cardiovascular Homeostasis, Center for Disruptive Cardiovascular Medicine, Kyushu University, Maidashi Higashi-ku, Fukuoka, Japan
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117
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Fudim M, Piccini JP. Treating cardiac dysrhythmias by targeting the neck: Off target or on the right track? J Cardiovasc Electrophysiol 2017; 28:909-911. [DOI: 10.1111/jce.13274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/05/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Marat Fudim
- Cardiac Electrophsiology Section, Division of Cardiology; Duke University Medical Center; Durham NC USA
| | - Jonathan P. Piccini
- Cardiac Electrophsiology Section, Division of Cardiology; Duke University Medical Center; Durham NC USA
- Duke Clinical Research Institute; Durham NC USA
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119
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Chu G, Choi P, McDonald VM. Sleep disturbance and sleep-disordered breathing in hemodialysis patients. Semin Dial 2017; 31:48-58. [DOI: 10.1111/sdi.12617] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ginger Chu
- Nephrology Department; Medical & Interventional Services; John Hunter Hospital; Hunter New England Local Health District NSW Australia
- School of Nursing and Midwifery; University of Newcastle; Newcastle NSW Australia
| | - Peter Choi
- Nephrology Department; Medical & Interventional Services; John Hunter Hospital; Hunter New England Local Health District NSW Australia
| | - Vanessa M. McDonald
- School of Nursing and Midwifery; University of Newcastle; Newcastle NSW Australia
- Priority Research Centre for Healthy Lung; School of Nursing and Midwifery; University of Newcastle; Newcastle NSW Australia
- Department of Respiratory and Sleep Medicine; John Hunter Hospital; Hunter New England Local Health District NSW Australia
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120
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McBryde FD, Hart EC, Ramchandra R, Paton JF. Evaluating the carotid bodies and renal nerves as therapeutic targets for hypertension. Auton Neurosci 2017; 204:126-130. [DOI: 10.1016/j.autneu.2016.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 11/30/2022]
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121
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Lobo MD, Sobotka PA, Pathak A. Interventional procedures and future drug therapy for hypertension. Eur Heart J 2017; 38:1101-1111. [PMID: 27406184 PMCID: PMC5400047 DOI: 10.1093/eurheartj/ehw303] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/09/2016] [Accepted: 06/16/2016] [Indexed: 02/06/2023] Open
Abstract
Hypertension management poses a major challenge to clinicians globally once non-drug (lifestyle) measures have failed to control blood pressure (BP). Although drug treatment strategies to lower BP are well described, poor control rates of hypertension, even in the first world, suggest that more needs to be done to surmount the problem. A major issue is non-adherence to antihypertensive drugs, which is caused in part by drug intolerance due to side effects. More effective antihypertensive drugs are therefore required which have excellent tolerability and safety profiles in addition to being efficacious. For those patients who either do not tolerate or wish to take medication for hypertension or in whom BP control is not attained despite multiple antihypertensives, a novel class of interventional procedures to manage hypertension has emerged. While most of these target various aspects of the sympathetic nervous system regulation of BP, an additional procedure is now available, which addresses mechanical aspects of the circulation. Most of these new devices are supported by early and encouraging evidence for both safety and efficacy, although it is clear that more rigorous randomized controlled trial data will be essential before any of the technologies can be adopted as a standard of care.
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Affiliation(s)
- Melvin D. Lobo
- Barts BP Centre of Excellence, Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS Trust, London, UK
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Queen Mary University of London, London, UK
| | - Paul A. Sobotka
- The Ohio State University, Columbus, OH, USA
- ROX Medical, San Clemente, CA, USA
| | - Atul Pathak
- Department of Cardiovascular Medicine, Hypertension and Heart Failure Unit, Health Innovation Lab (Hi-Lab) Clinique Pasteur, Toulouse, France
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122
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Larson KF, Limberg JK, Baker SE, Joyner MJ, Curry TB. Intact blood pressure, but not sympathetic, responsiveness to sympathoexcitatory stimuli in a patient with unilateral carotid body resection. Physiol Rep 2017; 5:5/7/e13212. [PMID: 28364029 PMCID: PMC5392508 DOI: 10.14814/phy2.13212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 11/24/2022] Open
Abstract
Despite rapidly growing interest in the therapeutic resection of the carotid body (CB) chemoreceptors, few physiologic studies exist on the consequences of unilateral CB resection. We present a case of an otherwise healthy postmenopausal female who underwent unilateral CB resection for a paraganglioma. Approximately 4 years postoperatively, she underwent analysis of her sympathetic and hemodynamic responses to hypoxia, lower body negative pressure, cold pressor test (CPT), and ischemic hand grip exercise and postexercise ischemia (IHE/PEI). Hypoxic ventilatory response and baroreflex sensitivity were relatively normal. Hemodynamic responses to IHE/PEI and CPT showed characteristic increases in cardiac output (from 3.9 L/min to 5.2 L/min [IHE/PEI] and 4.9 L/min [CPT]) and blood pressure (from 126/72 mmHg to 161/87 mmHg [IHE/PEI] and 171/93 mmHg [CPT]). However, muscle sympathetic nerve activity (microneurography of the peroneal nerve) decreased from baseline during IHE/PEI and CPT (burst incidence nadir of 45% and 40% of baseline, respectively) and there was no observable change in total peripheral resistance (from 24 mmHg*min/L to 22 mmHg*min/L [IHE/PEI] and 25 mmHg*min/L [CPT]). These findings illustrate intact blood pressure responsiveness despite attenuated sympathoexcitation, possibly due to an increase in cardiac output and/or adaptive inhibitory effect of the baroreflex on peripheral sympathetic activity.
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Affiliation(s)
| | | | - Sarah E Baker
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | | | - Timothy B Curry
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
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123
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Roozekrans M, Olofsen E, van der Schrier R, Boom M, Mooren R, Dahan A. Doxapram-mediated Increase in Cardiac Output Reduces Opioid Plasma Concentrations: A Pharmacokinetic/Pharmacodynamic-Pharmacokinetic/Pharmacodynamic Modeling Study in Healthy Volunteers. Clin Pharmacol Ther 2017; 102:115-122. [DOI: 10.1002/cpt.601] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 11/09/2022]
Affiliation(s)
- M Roozekrans
- Department of Anesthesiology; Leiden University Medical Center; Leiden The Netherlands
| | - E Olofsen
- Department of Anesthesiology; Leiden University Medical Center; Leiden The Netherlands
| | - R van der Schrier
- Department of Anesthesiology; Leiden University Medical Center; Leiden The Netherlands
| | - M Boom
- Department of Anesthesiology; Leiden University Medical Center; Leiden The Netherlands
| | - R Mooren
- Department of Anesthesiology; Leiden University Medical Center; Leiden The Netherlands
| | - A Dahan
- Department of Anesthesiology; Leiden University Medical Center; Leiden The Netherlands
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Sacramento JF, Ribeiro MJ, Rodrigues T, Olea E, Melo BF, Guarino MP, Fonseca-Pinto R, Ferreira CR, Coelho J, Obeso A, Seiça R, Matafome P, Conde SV. Functional abolition of carotid body activity restores insulin action and glucose homeostasis in rats: key roles for visceral adipose tissue and the liver. Diabetologia 2017; 60:158-168. [PMID: 27744526 DOI: 10.1007/s00125-016-4133-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022]
Abstract
AIMS/HYPOTHESIS We recently described that carotid body (CB) over-activation is involved in the aetiology of insulin resistance and arterial hypertension in animal models of the metabolic syndrome. Additionally, we have demonstrated that CB activity is increased in animal models of insulin resistance, and that carotid sinus nerve (CSN) resection prevents the development of insulin resistance and arterial hypertension induced by high-energy diets. Here, we tested whether the functional abolition of CB by CSN transection would reverse pre-established insulin resistance, dyslipidaemia, obesity, autonomic dysfunction and hypertension in animal models of the metabolic syndrome. The effect of CSN resection on insulin signalling pathways and tissue-specific glucose uptake was evaluated in skeletal muscle, adipose tissue and liver. METHODS Experiments were performed in male Wistar rats submitted to two high-energy diets: a high-fat diet, representing a model of insulin resistance, hypertension and obesity, and a high-sucrose diet, representing a lean model of insulin resistance and hypertension. Half of each group was submitted to chronic bilateral resection of the CSN. Age-matched control rats were also used. RESULTS CSN resection normalised systemic sympathetic nervous system activity and reversed weight gain induced by high-energy diets. It also normalised plasma glucose and insulin levels, insulin sensitivity lipid profile, arterial pressure and endothelial function by improving glucose uptake by the liver and perienteric adipose tissue. CONCLUSIONS/INTERPRETATION We concluded that functional abolition of CB activity restores insulin sensitivity and glucose homeostasis by positively affecting insulin signalling pathways in visceral adipose tissue and liver.
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Affiliation(s)
- Joana F Sacramento
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Maria J Ribeiro
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Tiago Rodrigues
- Laboratório de Fisiologia, Instituto Biomédico de Investigação de Luz e Imagem (IBILI), Faculdade de Medicina, Universidade de Coimbra, Coimbra, Portugal
| | - Elena Olea
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina. Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Salud Carlos III (ISCIII), Valladolid, España
| | - Bernardete F Melo
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Maria P Guarino
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
- Unidade de Investigação em Saúde (UIS), Escola Superior de Saúde de Leiria, Instituto Politécnico de Leiria, Leiria, Portugal
| | - Rui Fonseca-Pinto
- Escola Superior de Tecnologia e Gestão, Instituto Politécnico de Leiria, Leiria, Portugal
- Instituto de Telecomunicações, Leiria, Portugal
| | - Cristiana R Ferreira
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Joana Coelho
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Ana Obeso
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina. Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Salud Carlos III (ISCIII), Valladolid, España
| | - Raquel Seiça
- Laboratório de Fisiologia, Instituto Biomédico de Investigação de Luz e Imagem (IBILI), Faculdade de Medicina, Universidade de Coimbra, Coimbra, Portugal
| | - Paulo Matafome
- Laboratório de Fisiologia, Instituto Biomédico de Investigação de Luz e Imagem (IBILI), Faculdade de Medicina, Universidade de Coimbra, Coimbra, Portugal
- Instituto Politécnico de Coimbra, Escola Superior de Tecnologia da Saúde (ESTeSC), Departmento de Ciências Complementares, Coimbra, Portugal
| | - Sílvia V Conde
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal.
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McBryde FD, Malpas SC, Paton JFR. Intracranial mechanisms for preserving brain blood flow in health and disease. Acta Physiol (Oxf) 2017; 219:274-287. [PMID: 27172364 DOI: 10.1111/apha.12706] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/03/2016] [Accepted: 05/06/2016] [Indexed: 12/19/2022]
Abstract
The brain is an exceptionally energetically demanding organ with little metabolic reserve, and multiple systems operate to protect and preserve the brain blood supply. But how does the brain sense its own perfusion? In this review, we discuss how the brain may harness the cardiovascular system to counter threats to cerebral perfusion sensed via intracranial pressure (ICP), cerebral oxygenation and ischaemia. Since the work of Cushing over 100 years ago, the existence of brain baroreceptors capable of eliciting increases in sympathetic outflow and blood pressure has been hypothesized. In the clinic, this response has generally been thought to occur only in extremis, to perfuse the severely ischaemic brain as cerebral autoregulation fails. We review evidence that pressor responses may also occur with smaller, physiologically relevant increases in ICP. The incoming brain oxygen supply is closely monitored by the carotid chemoreceptors; however, hypoxia and other markers of ischaemia are also sensed intrinsically by astrocytes or other support cells within brain tissue itself and elicit reactive hyperaemia. Recent studies suggest that astrocytic oxygen signalling within the brainstem may directly affect sympathetic nerve activity and blood pressure. We speculate that local cerebral oxygen tension is a major determinant of the mean level of arterial pressure and discuss recent evidence that this may be the case. We conclude that intrinsic intra- and extra-cranial mechanisms sense and integrate information about hypoxia/ischaemia and ICP and play a major role in determining the long-term level of sympathetic outflow and arterial pressure, to optimize cerebral perfusion.
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Affiliation(s)
- F. D. McBryde
- Department of Physiology; Faculty of Medical and Health Sciences; University of Auckland; Auckland New Zealand
- School of Physiology, Pharmacology & Neuroscience; Biomedical Sciences; University of Bristol; Bristol UK
| | - S. C. Malpas
- Department of Physiology; Faculty of Medical and Health Sciences; University of Auckland; Auckland New Zealand
| | - J. F. R. Paton
- Department of Physiology; Faculty of Medical and Health Sciences; University of Auckland; Auckland New Zealand
- School of Physiology, Pharmacology & Neuroscience; Biomedical Sciences; University of Bristol; Bristol UK
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126
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Katayama PL. Adrenaline and the carotid body during hypoglycaemia: an amplifying mechanism? J Physiol 2016; 594:7161-7162. [PMID: 27976392 DOI: 10.1113/jp273238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Pedro Lourenço Katayama
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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127
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Welch BT, Petersen-Jones HG, Eugene AR, Brinjikji W, Kallmes DF, Curry TB, Joyner MJ, Limberg JK. Impact of sleep disordered breathing on carotid body size. Respir Physiol Neurobiol 2016; 236:5-10. [PMID: 27989890 DOI: 10.1016/j.resp.2016.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/18/2016] [Accepted: 10/27/2016] [Indexed: 12/11/2022]
Abstract
We tested the hypotheses that: (1) carotid body size can be measured by computed tomographic angiography (CTA) with high inter-observer agreement, and (2) patients with sleep apnea exhibit larger carotid bodies than those without sleep apnea. A chart review was conducted from patients who underwent neck CTA and polysomnography at the Mayo Clinic between January 2000 and February 2015. Widest axial measurements of the carotid bodies, performed independently by two radiologists, were possible in 81% of patients. Intra-class correlation coefficients ranged from 0.93 to 0.95 (Right carotid body: 0.93; Left: 0.94; Average: 0.95). Widest axial measurements of the carotid bodies were greater in patients with sleep apnea (n=32) compared to controls (n=46, P-value range 0.02-0.04). After adjusting for age, no differences in carotid body size were observed between the patient groups (P-value range 0.45-0.59). We conclude carotid body size can be detected by CTA with high inter-observer agreement; however, carotid body size is not increased in patients with sleep apnea.
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Affiliation(s)
- Brian T Welch
- Department of Radiology, Mayo Clinic, Rochester, MN, USA.
| | | | - Andy R Eugene
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA.
| | | | | | - Timothy B Curry
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA.
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128
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Abstract
The discovery of carotid bodies as sensory receptors for detecting arterial blood oxygen levels, and the identification and elucidation of the roles of hypoxia-inducible factors (HIFs) in oxygen homeostasis have propelled the field of oxygen biology. This review highlights the gas-messenger signaling mechanisms associated with oxygen sensing, as well as transcriptional and non-transcriptional mechanisms underlying the maintenance of oxygen homeostasis by HIFs and their relevance to physiology and pathology.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, Illinois;
| | - Gregg L Semenza
- Departments of Pediatrics, Medicine, Oncology, Radiation Oncology, and Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland; and McKusick-Nathans Institute of Genetic Medicine and Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
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129
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Siński M, Lewandowski J, Dobosiewicz A, Przybylski J, Abramczyk P, Gaciong Z. The effect of hyperoxia on central blood pressure in healthy subjects. Arch Med Sci 2016; 12:992-999. [PMID: 27695489 PMCID: PMC5016570 DOI: 10.5114/aoms.2015.49038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/30/2015] [Indexed: 01/04/2023] Open
Abstract
INTRODUCTION Hyperoxia increases total peripheral resistance by acting locally but also inhibits the activity of carotid body chemoreceptors. We studied the effect of hyperoxia on central pressure in normotensive subjects. MATERIAL AND METHODS Medical air followed by 100% oxygen was provided to 19 subjects (12/7 female/male, age 28.2 ±1.1 years) for 15 min through a non-rebreather mask. Central blood pressure was then measured using applanation tonometry. RESULTS After the first 2 min of hyperoxia, heart rate decreased significantly (65 ±2.6 beats/min vs. 61 ±2.1 beats/min, p = 0.0002). Peripheral and central blood pressure remained unchanged, while hemoglobin oxygen saturation and subendocardial viability ratio index increased (97 ±0.4% vs. 99 ±0.2%, p = 0.03; 168 ±8.4% vs. 180 ±8.2%, p = 0.009). After 15 min of 100% oxygen ventilation, heart rate and peripheral and central blood pressures remained unchanged from the first 2 min. The augmentation index, augmentation pressure and ejection duration increased as compared to baseline values and those obtained at 2 min (-5.1 ±2.9% vs. -1.2 ±2.6%, p = 0.005 and -4.6 ±2.7% vs. -1.2 ±2.6%, p = 0.0015; -1.3 ±0.7 mm Hg vs. -0.2 ±1.2 mm Hg, p = 0.003 and -1.1 ±0.7 mm Hg vs. -0.2 ±1.2 mm Hg, p = 0.012; 323 ±3.6 ms vs. 330 ±3.5 ms, p = 0.0002 and 326 ±3.5 ms vs. 330 ±3.5 ms, p = 0.021, respectively). CONCLUSIONS The present study shows that hyperoxia does not affect central blood pressure in young healthy subjects and may improve myocardial blood supply estimated indirectly from applanation tonometry.
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Affiliation(s)
- Maciej Siński
- Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland
| | - Jacek Lewandowski
- Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland
| | - Anna Dobosiewicz
- Department of Pulmonary Circulation and Thromboembolic Diseases, Center of Postgraduate Medical Education, Otwock, Poland
| | - Jacek Przybylski
- Department of Biophysics and Physiology, Medical University of Warsaw, Warsaw, Poland
| | - Piotr Abramczyk
- Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland
| | - Zbigniew Gaciong
- Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland
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130
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Pijacka W, McBryde FD, Marvar PJ, Lincevicius GS, Abdala APL, Woodward L, Li D, Paterson DJ, Paton JFR. Carotid sinus denervation ameliorates renovascular hypertension in adult Wistar rats. J Physiol 2016; 594:6255-6266. [PMID: 27510951 DOI: 10.1113/jp272708] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/03/2016] [Indexed: 01/24/2023] Open
Abstract
KEY POINTS Peripheral chemoreflex sensitization is a feature of renovascular hypertension. Carotid sinus nerve denervation (CSD) has recently been shown to relieve hypertension and reduce sympathetic activity in other rat models of hypertension. We show that CSD in renovascular hypertension halts further increases in blood pressure. Possible mechanisms include improvements in baroreceptor reflex sensitivity and renal function, restoration of cardiac calcium signalling towards control levels, and reduced neural inflammation. Our data suggest that the peripheral chemoreflex may be a viable therapeutic target for renovascular hypertension. ABSTRACT The peripheral chemoreflex is known to be hyper-responsive in both spontaneously hypertensive (SHR) and Goldblatt hypertensive (two kidney one clip; 2K1C) rats. We have previously shown that carotid sinus nerve denervation (CSD) reduces arterial blood pressure (ABP) in SHR. In the present study, we show that CSD ameliorates 2K1C hypertension and reveal the potential underlying mechanisms. Adult Wistar rats were instrumented to record ABP via telemetry, and then underwent CSD (n = 9) or sham CSD (n = 9) 5 weeks after renal artery clipping, in comparison with normal Wistar rats (n = 5). After 21 days, renal function was assessed, and tissue was collected to assess sympathetic postganglionic intracellular calcium transients ([Ca2+ ]i ) and immune cell infiltrates. Hypertensive 2K1C rats showed a profound elevation in ABP (Wistar: 98 ± 4 mmHg vs. 2K1C: 147 ± 8 mmHg; P < 0.001), coupled with impairments in renal function and baroreflex sensitivity, increased neuroinflammatory markers and enhanced [Ca2+ ]I in stellate neurons (P < 0.05). CSD reduced ABP in 2K1C+CSD rats and prevented the further progressive increase in ABP seen in 2K1C+sham CSD rats, with a between-group difference of 14 ± 2 mmHg by week 3 (P < 0.01), which was accompanied by improvements in both baroreflex control and spectral indicators of cardiac sympatho-vagal balance. Furthermore, CSD improved protein and albuminuria, decreased [Ca2+ ]i evoked responses from stellate neurons, and also reduced indicators of brainstem inflammation. In summary, CSD in 2K1C rats reduces the hypertensive burden and improves renal function. This may be mediated by improvements in autonomic balance, functional remodelling of post-ganglionic neurons and reduced inflammation. Our results suggest that the peripheral chemoreflex may be considered as a potential therapeutic target for controlling renovascular hypertension.
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Affiliation(s)
- Wioletta Pijacka
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Fiona D McBryde
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Paul J Marvar
- Department of Pharmacology and Physiology, The George Washington University School of Medical and Health Sciences, Washington, DC, USA
| | - Gisele S Lincevicius
- Cardiovascular Division - Department of Physiology, Escola Paulista de Medicina, Universidade Federal de, Sao Paulo, Brazil
| | - Ana P L Abdala
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Lavinia Woodward
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.
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131
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Niewinski P, Janczak D, Rucinski A, Tubek S, Engelman ZJ, Piesiak P, Jazwiec P, Banasiak W, Fudim M, Sobotka PA, Javaheri S, Hart EC, Paton JF, Ponikowski P. Carotid body resection for sympathetic modulation in systolic heart failure: results from first-in-man study. Eur J Heart Fail 2016; 19:391-400. [DOI: 10.1002/ejhf.641] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 07/10/2016] [Accepted: 07/25/2016] [Indexed: 12/30/2022] Open
Affiliation(s)
- Piotr Niewinski
- Department of Cardiology, Centre for Heart Disease; 4th Military Hospital; Wroclaw Poland
| | - Dariusz Janczak
- Department of Vascular Surgery; 4th Military Hospital; Wroclaw Poland
| | - Artur Rucinski
- Department of Vascular Surgery; 4th Military Hospital; Wroclaw Poland
| | - Stanislaw Tubek
- Department of Cardiology, Centre for Heart Disease; 4th Military Hospital; Wroclaw Poland
- Department of Heart Diseases, Faculty of Health Sciences; Wroclaw Medical University; Wroclaw Poland
| | | | - Pawel Piesiak
- Department of Pulmonology and Lung Cancer; Medical University; Wroclaw Poland
| | - Przemyslaw Jazwiec
- Department of Radiology and Diagnostics Imaging; 4th Military Hospital; Wroclaw Poland
| | - Waldemar Banasiak
- Department of Cardiology, Centre for Heart Disease; 4th Military Hospital; Wroclaw Poland
| | - Marat Fudim
- Department of Cardiology; Duke University School of Medicine; Durham NC USA
| | - Paul A. Sobotka
- Cibiem Inc.; Los Altos CA USA
- The Ohio State University; Columbus OH USA
| | - Shahrokh Javaheri
- Bethesda North Hospital; Cincinnati OH USA
- University of Cincinnati; Cincinnati OH USA
| | - Emma C.J. Hart
- School of Physiology and Pharmacology, Clinical Research & Imaging Centre; University of Bristol; Bristol UK
| | - Julian F.R. Paton
- School of Physiology and Pharmacology, Clinical Research & Imaging Centre; University of Bristol; Bristol UK
| | - Piotr Ponikowski
- Department of Cardiology, Centre for Heart Disease; 4th Military Hospital; Wroclaw Poland
- Department of Heart Diseases, Faculty of Health Sciences; Wroclaw Medical University; Wroclaw Poland
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132
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Abstract
Cardiac control is mediated via a series of reflex control networks involving somata in the (i) intrinsic cardiac ganglia (heart), (ii) intrathoracic extracardiac ganglia (stellate, middle cervical), (iii) superior cervical ganglia, (iv) spinal cord, (v) brainstem, and (vi) higher centers. Each of these processing centers contains afferent, efferent, and local circuit neurons, which interact locally and in an interdependent fashion with the other levels to coordinate regional cardiac electrical and mechanical indices on a beat-to-beat basis. This control system is optimized to respond to normal physiological stressors (standing, exercise, and temperature); however, it can be catastrophically disrupted by pathological events such as myocardial ischemia. In fact, it is now recognized that autonomic dysregulation is central to the evolution of heart failure and arrhythmias. Autonomic regulation therapy is an emerging modality in the management of acute and chronic cardiac pathologies. Neuromodulation-based approaches that target select nexus points of this hierarchy for cardiac control offer unique opportunities to positively affect therapeutic outcomes via improved efficacy of cardiovascular reflex control. As such, understanding the anatomical and physiological basis for such control is necessary to implement effectively novel neuromodulation therapies. © 2016 American Physiological Society. Compr Physiol 6:1635-1653, 2016.
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Affiliation(s)
- Jeffrey L Ardell
- Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California, USA
| | - John Andrew Armour
- Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California, USA
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133
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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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134
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Purinergic receptors in the carotid body as a new drug target for controlling hypertension. Nat Med 2016; 22:1151-1159. [PMID: 27595323 DOI: 10.1038/nm.4173] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/27/2016] [Indexed: 11/09/2022]
Abstract
In view of the high proportion of individuals with resistance to antihypertensive medication and/or poor compliance or tolerance of this medication, new drugs to treat hypertension are urgently needed. Here we show that peripheral chemoreceptors generate aberrant signaling that contributes to high blood pressure in hypertension. We discovered that purinergic receptor P2X3 (P2rx3, also known as P2x3) mRNA expression is upregulated substantially in chemoreceptive petrosal sensory neurons in rats with hypertension. These neurons generate both tonic drive and hyperreflexia in hypertensive (but not normotensive) rats, and both phenomena are normalized by the blockade of P2X3 receptors. Antagonism of P2X3 receptors also reduces arterial pressure and basal sympathetic activity and normalizes carotid body hyperreflexia in conscious rats with hypertension; no effect was observed in rats without hypertension. We verified P2X3 receptor expression in human carotid bodies and observed hyperactivity of carotid bodies in individuals with hypertension. These data support the identification of the P2X3 receptor as a potential new target for the control of human hypertension.
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135
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Narkiewicz K, Ratcliffe LEK, Hart EC, Briant LJB, Chrostowska M, Wolf J, Szyndler A, Hering D, Abdala AP, Manghat N, Burchell AE, Durant C, Lobo MD, Sobotka PA, Patel NK, Leiter JC, Engelman ZJ, Nightingale AK, Paton JFR. Unilateral Carotid Body Resection in Resistant Hypertension: A Safety and Feasibility Trial. ACTA ACUST UNITED AC 2016; 1:313-324. [PMID: 27766316 PMCID: PMC5063532 DOI: 10.1016/j.jacbts.2016.06.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/17/2022]
Abstract
Animal and human data indicate pathological afferent signaling emanating from the carotid body that drives sympathetically mediated elevations in blood pressure in conditions of hypertension. This first-in-man, proof-of-principle study tested the safety and feasibility of unilateral carotid body resection in 15 patients with drug-resistant hypertension. The procedure proved to be safe and feasible. Overall, no change in blood pressure was found. However, 8 patients showed significant reductions in ambulatory blood pressure coinciding with decreases in sympathetic activity. The carotid body may be a novel target for treating an identifiable subpopulation of humans with hypertension.
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Key Words
- ABP, ambulatory blood pressure
- ASBP, ambulatory systolic blood pressure
- BRS, baroreceptor reflex sensitivity
- CB, carotid body
- HRV, heart rate variability
- HVR, hypoxic ventilatory response
- MSNA, muscle sympathetic nerve activity
- OBP, office blood pressure
- OSBP, office systolic blood pressure
- afferent drive
- baroreceptor reflex
- hypertension
- hypoxia
- peripheral chemoreceptor
- sympathetic nervous system
- uCB, unilateral carotid body
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Affiliation(s)
- Krzysztof Narkiewicz
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Laura E K Ratcliffe
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Emma C Hart
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom; School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Linford J B Briant
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Marzena Chrostowska
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Jacek Wolf
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Anna Szyndler
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Dagmara Hering
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Ana P Abdala
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Nathan Manghat
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Amy E Burchell
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Claire Durant
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Melvin D Lobo
- NIHR Barts Cardiovascular Biomedical Research Unit, William Harvey Research Institute, QMUL, Charterhouse Square, London, United Kingdom
| | - Paul A Sobotka
- Department of Internal Medicine, Division of Cardiovascular Diseases, The Ohio State University, Columbus, Ohio
| | - Nikunj K Patel
- Neurosurgery, North Bristol NHS Trust, Southmead Hospital, Bristol, United Kingdom
| | - James C Leiter
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | | | - Angus K Nightingale
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
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136
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Gamboa A, Figueroa R, Paranjape SY, Farley G, Diedrich A, Biaggioni I. Autonomic Blockade Reverses Endothelial Dysfunction in Obesity-Associated Hypertension. Hypertension 2016; 68:1004-10. [PMID: 27528067 DOI: 10.1161/hypertensionaha.116.07681] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/19/2016] [Indexed: 01/04/2023]
Abstract
Impaired nitric oxide (NO) vasodilation (endothelial dysfunction) is associated with obesity and thought to be a factor in the development of hypertension. We previously found that NO synthesis inhibition had similar pressor effects in obese hypertensives compared with healthy control during autonomic blockade, suggesting that impaired NO vasodilation is secondary to sympathetic activation. We tested this hypothesis by determining the effect of autonomic blockade (trimethaphan 4 mg/min IV) on NO-mediated vasodilation (increase in forearm blood flow to intrabrachial acetylcholine) compared with endothelial-independent vasodilation (intrabrachial sodium nitroprusside) in obese hypertensive subjects (30<body mass index<40 kg/m(2)). Acetylcholine and sodium nitroprusside were given at equipotent doses (10, 30, and 50 μg/min and 1, 2, and 3 μg/min, respectively) to 14 obese subjects (49±3.6 years, 34±1 kg/m(2), 165/94±7/6 mm Hg), on separate occasions 1 month apart, randomly assigned. Autonomic blockade increased basal forearm blood flow (from 3.9±0.7 to 5.2±1.2 mL/100 mL per minute, P=0.078). As expected, NO-mediated vasodilation was blunted on the intact day compared with NO-independent vasodilation; forearm blood flow increased from 3.6±0.6 to 10.1±1.1 with the highest dose of nitroprusside, but only from 3.7±0.4 to 7.2±0.8 mL/100 mL per minute with the highest dose of acetylcholine, P<0.05. In contrast, forearm blood flow responses to acetylcholine were restored by autonomic blockade and were no longer different to nitroprusside (from 6.2±1.1 to 11.4±1.6 mL/100 mL per minute and from 5.2±0.9 to 12.5±0.9, respectively, P=0.58). Our results support the concept that sympathetic activation contributes to the impairment in NO-mediated vasodilation seen in obesity-associated hypertension and provides further rationale to explore it as a therapeutic target.
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Affiliation(s)
- Alfredo Gamboa
- From the Division of Clinical Pharmacology (A.G., R.F., S.Y.P., G.F., A.D., I.B.), Departments of Medicine (A.G., R.F., S.Y.P., G.F., A.D., I.B.), and Pharmacology (I.B.), Vanderbilt University, Nashville, TN.
| | - Rocío Figueroa
- From the Division of Clinical Pharmacology (A.G., R.F., S.Y.P., G.F., A.D., I.B.), Departments of Medicine (A.G., R.F., S.Y.P., G.F., A.D., I.B.), and Pharmacology (I.B.), Vanderbilt University, Nashville, TN
| | - Sachin Y Paranjape
- From the Division of Clinical Pharmacology (A.G., R.F., S.Y.P., G.F., A.D., I.B.), Departments of Medicine (A.G., R.F., S.Y.P., G.F., A.D., I.B.), and Pharmacology (I.B.), Vanderbilt University, Nashville, TN
| | - Ginnie Farley
- From the Division of Clinical Pharmacology (A.G., R.F., S.Y.P., G.F., A.D., I.B.), Departments of Medicine (A.G., R.F., S.Y.P., G.F., A.D., I.B.), and Pharmacology (I.B.), Vanderbilt University, Nashville, TN
| | - Andre Diedrich
- From the Division of Clinical Pharmacology (A.G., R.F., S.Y.P., G.F., A.D., I.B.), Departments of Medicine (A.G., R.F., S.Y.P., G.F., A.D., I.B.), and Pharmacology (I.B.), Vanderbilt University, Nashville, TN
| | - Italo Biaggioni
- From the Division of Clinical Pharmacology (A.G., R.F., S.Y.P., G.F., A.D., I.B.), Departments of Medicine (A.G., R.F., S.Y.P., G.F., A.D., I.B.), and Pharmacology (I.B.), Vanderbilt University, Nashville, TN
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137
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Kim SJ, Pilowsky PM, Farnham MMJ. Intrathecal Intermittent Orexin-A Causes Sympathetic Long-Term Facilitation and Sensitizes the Peripheral Chemoreceptor Response to Hypoxia in Rats. J Pharmacol Exp Ther 2016; 358:492-501. [PMID: 27384072 DOI: 10.1124/jpet.116.234443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/05/2016] [Indexed: 11/22/2022] Open
Abstract
Intermittent hypoxia causes a persistent increase in sympathetic nerve activity (SNA), which progresses to hypertension in conditions such as obstructive sleep apnea. Orexins (A and B) are hypothalamic neurotransmitters with arousal-promoting and sympathoexcitatory effects. We investigated whether the sustained elevation of SNA, termed sympathetic long-term facilitation, after acute intermittent hypoxia (AIH) is caused by endogenous orexin acting on spinal sympathetic preganglionic neurons. The role of orexin in the increased SNA response to AIH was investigated in urethane-anesthetized, vagotomized, and artificially ventilated Sprague-Dawley rats (n = 58). A spinally infused subthreshold dose of orexin-A (intermittent; 0.1 nmol × 10) produced long-term enhancement in SNA (41.4% ± 6.9%) from baseline. This phenomenon was not produced by the same dose of orexin-A administered as a bolus intrathecal infusion (1 nmol; 7.3% ± 2.3%). The dual orexin receptor blocker, Almorexant, attenuated the effect of sympathetic long-term facilitation generated by intermittent orexin-A (20.7% ± 4.5% for Almorexant at 30 mg∙kg(-1) and 18.5% ± 1.2% for 75 mg∙kg(-1)), but not in AIH. The peripheral chemoreflex sympathoexcitatory response to hypoxia was greatly enhanced by intermittent orexin-A and AIH. In both cases, the sympathetic chemoreflex sensitization was reduced by Almorexant. Taken together, spinally acting orexin-A is mechanistically sufficient to evoke sympathetic long-term facilitation. However, AIH-induced sympathetic long-term facilitation appears to rely on mechanisms that are independent of orexin neurotransmission. Our findings further reveal that the activation of spinal orexin receptors is critical to enhance peripheral chemoreceptor responses to hypoxia after AIH.
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Affiliation(s)
- Seung Jae Kim
- Department of Physiology, Sydney Medical School, University of Sydney, and Heart Research Institute, Sydney, New South Wales, Australia
| | - Paul M Pilowsky
- Department of Physiology, Sydney Medical School, University of Sydney, and Heart Research Institute, Sydney, New South Wales, Australia
| | - Melissa M J Farnham
- Department of Physiology, Sydney Medical School, University of Sydney, and Heart Research Institute, Sydney, New South Wales, Australia
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138
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Del Rio R, Andrade DC, Lucero C, Arias P, Iturriaga R. Carotid Body Ablation Abrogates Hypertension and Autonomic Alterations Induced by Intermittent Hypoxia in Rats. Hypertension 2016; 68:436-45. [PMID: 27381902 DOI: 10.1161/hypertensionaha.116.07255] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/06/2016] [Indexed: 01/12/2023]
Abstract
Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, enhances carotid body (CB) chemosensory responses to hypoxia and produces autonomic dysfunction, cardiac arrhythmias, and hypertension. We tested whether autonomic alterations, arrhythmogenesis, and the progression of hypertension induced by CIH depend on the enhanced CB chemosensory drive, by ablation of the CB chemoreceptors. Male Sprague-Dawley rats were exposed to control (Sham) conditions for 7 days and then to CIH (5% O2, 12/h 8 h/d) for a total of 28 days. At 21 days of CIH exposure, rats underwent bilateral CB ablation and then exposed to CIH for 7 additional days. Arterial blood pressure and ventilatory chemoreflex response to hypoxia were measured in conscious rats. In addition, cardiac autonomic imbalance, cardiac baroreflex gain, and arrhythmia score were assessed during the length of the experiments. In separate experimental series, we measured extracellular matrix remodeling content in cardiac atrial tissue and systemic oxidative stress. CIH induced hypertension, enhanced ventilatory response to hypoxia, induced autonomic imbalance toward sympathetic preponderance, reduced baroreflex gain, and increased arrhythmias and atrial fibrosis. CB ablation normalized blood pressure, reduced ventilatory response to hypoxia, and restored cardiac autonomic and baroreflex function. In addition, CB ablation reduced the number of arrhythmias, but not extracellular matrix remodeling or systemic oxidative stress, suggesting that reductions in arrhythmia incidence during CIH were related to normalization of cardiac autonomic balance. Present results show that autonomic alterations induced by CIH are critically dependent on the CB and support a main role for the CB in the CIH-induced hypertension.
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Affiliation(s)
- Rodrigo Del Rio
- From the Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, Santiago, Chile (R.D.R., C.L.); and Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile (D.C.A., P.A., R.I.)
| | - David C Andrade
- From the Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, Santiago, Chile (R.D.R., C.L.); and Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile (D.C.A., P.A., R.I.)
| | - Claudia Lucero
- From the Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, Santiago, Chile (R.D.R., C.L.); and Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile (D.C.A., P.A., R.I.)
| | - Paulina Arias
- From the Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, Santiago, Chile (R.D.R., C.L.); and Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile (D.C.A., P.A., R.I.)
| | - Rodrigo Iturriaga
- From the Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile, Santiago, Chile (R.D.R., C.L.); and Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile (D.C.A., P.A., R.I.).
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139
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Mozer MT, Holbein WW, Joyner MJ, Curry TB, Limberg JK. Reductions in carotid chemoreceptor activity with low-dose dopamine improves baroreflex control of heart rate during hypoxia in humans. Physiol Rep 2016; 4:e12859. [PMID: 27418545 PMCID: PMC4945841 DOI: 10.14814/phy2.12859] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/13/2016] [Accepted: 06/18/2016] [Indexed: 11/24/2022] Open
Abstract
The purpose of the present investigation was to examine the contribution of the carotid body chemoreceptors to changes in baroreflex control of heart rate with exposure to hypoxia. We hypothesized spontaneous cardiac baroreflex sensitivity (scBRS) would be reduced with hypoxia and this effect would be blunted when carotid chemoreceptor activity was reduced with low-dose dopamine. Fifteen healthy adults (11 M/4 F) completed two visits randomized to intravenous dopamine or placebo (saline). On each visit, subjects were exposed to 5-min normoxia (~99% SpO2), followed by 5-min hypoxia (~84% SpO2). Blood pressure (intra-arterial catheter) and heart rate (ECG) were measured continuously and scBRS was assessed by spectrum and sequence methodologies. scBRS was reduced with hypoxia (P < 0.01). Using the spectrum analysis approach, the fall in scBRS with hypoxia was attenuated with infusion of low-dose dopamine (P < 0.01). The decrease in baroreflex sensitivity to rising pressures (scBRS "up-up") was also attenuated with low-dose dopamine (P < 0.05). However, dopamine did not attenuate the decrease in baroreflex sensitivity to falling pressures (scBRS "down-down"; P > 0.05). Present findings are consistent with a reduction in scBRS with systemic hypoxia. Furthermore, we show this effect is partially mediated by the carotid body chemoreceptors, given the fall in scBRS is attenuated when activity of the chemoreceptors is reduced with low-dose dopamine. However, the improvement in scBRS with dopamine appears to be specific to rising blood pressures. These results may have important implications for impairments in baroreflex function common in disease states of acute and/or chronic hypoxemia, as well as the experimental use of dopamine to assess such changes.
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Affiliation(s)
- Michael T Mozer
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | | | | | - Timothy B Curry
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
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140
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Baltzis D, Bakker JP, Patel SR, Veves A. Obstructive Sleep Apnea and Vascular Diseases. Compr Physiol 2016; 6:1519-28. [PMID: 27347900 DOI: 10.1002/cphy.c150029] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Obstructive sleep apnea (OSA) affects a large proportion of adults, and is as an independent risk factor for cerebrovascular and cardiovascular disease. The repetitive airway obstruction that characterizes OSA results in intermittent hypoxia, intrathoracic pressure swings, and sleep fragmentation, which in turn lead to sympathetic activation, oxidative stress, inflammation, and endothelial dysfunction. This review outlines the associations between OSA and vascular diseases and describes basic mechanisms that may be responsible for this association, in both the micro- and macrocirculation. It also reports on interventional studies that aim to ameliorate OSA and thereby reduce vascular disease burden. © 2016 American Physiological Society. Compr Physiol 6:1519-1528, 2016.
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Affiliation(s)
- Dimitrios Baltzis
- Microcirculation Lab and Joslin-Beth Israel Deaconess Foot Center, Harvard Medical School, Boston, USA
| | - Jessie P Bakker
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Harvard Medical School, Boston, USA
| | - Sanjay R Patel
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Harvard Medical School, Boston, USA
| | - Aristidis Veves
- Microcirculation Lab and Joslin-Beth Israel Deaconess Foot Center, Harvard Medical School, Boston, USA
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141
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Abstract
This brief review highlights new ideas about the role of the sympathetic nervous system in human blood pressure regulation. We emphasize how this role varies with age and sex and use our findings to raise questions about the sympathetic nervous system and hypertension in humans. We also focus on three additional areas, including (1) novel ideas about the carotid body and sympathoexcitation as it relates to hypertension, (2) clinical trials of renal denervation that attempted to treat hypertension by reducing ongoing sympathoexcitation, and (3) new ideas about resistant hypertension and cerebral blood flow. We further highlight that success of device-based therapy to modulate the sympathetic nervous system relies heavily on patient selection. Furthermore, data suggest that the majority of patients respond to anti-hypertensive therapy and the major cause of "resistant" hypertension is poor patient adherence. While the enthusiasm for device therapy or perhaps even "precision medicine" is high, it is likely that by far the most benefit to the most patients will occur via better screening, more aggressive therapy, and the development of strategies that improve patient adherence to medication regimens and lifestyle changes.
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Affiliation(s)
- Michael J Joyner
- Department of Anesthesiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA.
| | - Jacqueline K Limberg
- Department of Anesthesiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA
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142
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Abstract
It has been known for many decades that multiple abnormalities of the autonomic nervous system (ANS) are present in heart failure (HF). Moreover, many of the effective therapies currently used to treat HF have either direct or indirect effects on the ANS. While therapies that block over-activity of the sympathetic nervous system are now standard of care, much less well studied are therapies aimed at augmenting the parasympathetic nervous system. This review will cover recent and ongoing investigations targeting modulation of the ANS, especially highlighting new and ongoing studies directed toward augmenting parasympathetic mechanisms.
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Affiliation(s)
- Mark E Dunlap
- MetroHealth Campus of Case Western Reserve University, 2500 MetroHealth Drive, Cleveland, OH, 44109, USA.
| | - Anju Bhardwaj
- MetroHealth Campus of Case Western Reserve University, 2500 MetroHealth Drive, Cleveland, OH, 44109, USA
| | - Paul J Hauptman
- Saint Louis University School of Medicine, St. Louis, MO, USA
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143
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Li A, Roy SH, Nattie EE. An augmented CO2 chemoreflex and overactive orexin system are linked with hypertension in young and adult spontaneously hypertensive rats. J Physiol 2016; 594:4967-80. [PMID: 27061304 DOI: 10.1113/jp272199] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/05/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Activation of central chemoreceptors by CO2 increases sympathetic nerve activity (SNA), arterial blood pressure (ABP) and breathing. These effects are exaggerated in spontaneously hypertensive rats (SHRs), resulting in an augmented CO2 chemoreflex that affects both breathing and ABP. The augmented CO2 chemoreflex and the high ABP are measureable in young SHRs (postnatal day 30-58) and become greater in adult SHRs. Blockade of orexin receptors can normalize the augmented CO2 chemoreflex and the high ABP in young SHRs and normalize the augmented CO2 chemoreflex and significantly lower the high ABP in adult SHRs. In the hypothalamus, SHRs have more orexin neurons, and a greater proportion of them increase their activity with CO2 . The orexin system is overactive in SHRs and contributes to the augmented CO2 chemoreflex and hypertension. Modulation of the orexin system may be beneficial in the treatment of neurogenic hypertension. ABSTRACT Activation of central chemoreceptors by CO2 increases arterial blood pressure (ABP), sympathetic nerve activity and breathing. In spontaneously hypertensive rats (SHRs), high ABP is associated with enhanced sympathetic nerve activity and peripheral chemoreflexes. We hypothesized that an augmented CO2 chemoreflex and overactive orexin system are linked with high ABP in both young (postnatal day 30-58) and adult SHRs (4-6 months). Our main findings are as follows. (i) An augmented CO2 chemoreflex and higher ABP in SHRs are measureable at a young age and increase in adulthood. In wakefulness, the ventilatory response to normoxic hypercapnia is higher in young SHRs (mean ± SEM: 179 ± 11% increase) than in age-matched normotensive Wistar-Kyoto rats (114 ± 9% increase), but lower than in adult SHRs (226 ± 10% increase; P < 0.05). The resting ABP is higher in young SHRs (122 ± 5 mmHg) than in age-matched Wistar-Kyoto rats (99 ± 5 mmHg), but lower than in adult SHRs (152 ± 4 mmHg; P < 0.05). (ii) Spontaneously hypertensive rats have more orexin neurons and more CO2 -activated orexin neurons in the hypothalamus. (iii) Antagonism of orexin receptors with a dual orexin receptor antagonist, almorexant, normalizes the augmented CO2 chemoreflex in young and adult SHRs and the high ABP in young SHRs and significantly lowers ABP in adult SHRs. (iv) Attenuation of peripheral chemoreflexes by hyperoxia does not abolish the augmented CO2 chemoreflex (breathing and ABP) in SHRs, which indicates an important role for the central chemoreflex. We suggest that an overactive orexin system may play an important role in the augmented central CO2 chemoreflex and in the development of hypertension in SHRs.
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Affiliation(s)
- Aihua Li
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, 1 Medical Center Drive, Lebanon, NH, 03756, USA
| | - Sarah H Roy
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, 1 Medical Center Drive, Lebanon, NH, 03756, USA
| | - Eugene E Nattie
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, 1 Medical Center Drive, Lebanon, NH, 03756, USA
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144
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Barnett WH, Abdala AP, Paton JFR, Rybak IA, Zoccal DB, Molkov YI. Chemoreception and neuroplasticity in respiratory circuits. Exp Neurol 2016; 287:153-164. [PMID: 27240520 DOI: 10.1016/j.expneurol.2016.05.036] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/22/2016] [Accepted: 05/26/2016] [Indexed: 12/20/2022]
Abstract
The respiratory central pattern generator must respond to chemosensory cues to maintain oxygen (O2) and carbon dioxide (CO2) homeostasis in the blood and tissues. To do this, sensorial cells located in the periphery and central nervous system monitor the arterial partial pressure of O2 and CO2 and initiate respiratory and autonomic reflex adjustments in conditions of hypoxia and hypercapnia. In conditions of chronic intermittent hypoxia (CIH), repeated peripheral chemoreceptor input mediated by the nucleus of the solitary tract induces plastic changes in respiratory circuits that alter baseline respiratory and sympathetic motor outputs and result in chemoreflex sensitization, active expiration, and arterial hypertension. Herein, we explored the hypothesis that the CIH-induced neuroplasticity primarily consists of increased excitability of pre-inspiratory/inspiratory neurons in the pre-Bötzinger complex. To evaluate this hypothesis and elucidate neural mechanisms for the emergence of active expiration and sympathetic overactivity in CIH-treated animals, we extended a previously developed computational model of the brainstem respiratory-sympathetic network to reproduce experimental data on peripheral and central chemoreflexes post-CIH. The model incorporated neuronal connections between the 2nd-order NTS neurons and peripheral chemoreceptors afferents, the respiratory pattern generator, and sympathetic neurons in the rostral ventrolateral medulla in order to capture key features of sympathetic and respiratory responses to peripheral chemoreflex stimulation. Our model identifies the potential neuronal groups recruited during peripheral chemoreflex stimulation that may be required for the development of inspiratory, expiratory and sympathetic reflex responses. Moreover, our model predicts that pre-inspiratory neurons in the pre-Bötzinger complex experience plasticity of channel expression due to excessive excitation during peripheral chemoreflex. Simulations also show that, due to positive interactions between pre-inspiratory neurons in the pre-Bötzinger complex and expiratory neurons in the retrotrapezoid nucleus, increased excitability of the former may lead to the emergence of the active expiratory pattern at normal CO2 levels found after CIH exposure. We conclude that neuronal type specific neuroplasticity in the pre-Bötzinger complex induced by repetitive episodes of peripheral chemoreceptor activation by hypoxia may contribute to the development of sympathetic over-activity and hypertension.
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Affiliation(s)
| | - Ana P Abdala
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, UK
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, UK
| | - Ilya A Rybak
- Drexel University College of Medicine, Philadelphia, PA, United States
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145
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Lohmeier TE, Iliescu R, Tudorancea I, Cazan R, Cates AW, Georgakopoulos D, Irwin ED. Chronic Interactions Between Carotid Baroreceptors and Chemoreceptors in Obesity Hypertension. Hypertension 2016; 68:227-35. [PMID: 27160198 DOI: 10.1161/hypertensionaha.116.07232] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 02/29/2016] [Indexed: 11/16/2022]
Abstract
Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension remain unclear. We investigated the chronic interactions of these reflexes in dogs with sympathetically mediated, obesity-induced hypertension based on the hypothesis that hypoxemia and tonic activation of carotid chemoreceptors may be associated with obesity. After 5 weeks on a high-fat diet, the animals experienced a 35% to 40% weight gain and increases in arterial pressure from 106±3 to 123±3 mm Hg and respiratory rate from 8±1 to 12±1 breaths/min along with hypoxemia (arterial partial pressure of oxygen=81±3 mm Hg) but eucapnia. During 7 days of carotid baroreflex activation by electric stimulation of the carotid sinus, tachypnea was attenuated, and hypertension was abolished before these variables returned to prestimulation values during a recovery period. After subsequent denervation of the carotid sinus region, respiratory rate decreased transiently in association with further sustained reductions in arterial partial pressure of oxygen (to 65±2 mm Hg) and substantial hypercapnia. Moreover, the severity of hypertension was attenuated from 125±2 to 116±3 mm Hg (45%-50% reduction). These findings suggest that hypoxemia may account for sustained stimulation of peripheral chemoreceptors in obesity and that this activation leads to compensatory increases in ventilation and central sympathetic outflow that contributes to neurogenically mediated hypertension. Furthermore, the excitatory effects of chemoreceptor hyperactivity are abolished by chronic activation of the carotid baroreflex.
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Affiliation(s)
- Thomas E Lohmeier
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
| | - Radu Iliescu
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
| | - Ionut Tudorancea
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
| | - Radu Cazan
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
| | - Adam W Cates
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
| | - Dimitrios Georgakopoulos
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
| | - Eric D Irwin
- From the Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (T.E.L.); Department of Pharmacology (R.I.) and Department of Physiology (I.T.), University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania; Colonial Pipeline Company, Atlanta, GA (R.C.); CVRx, Inc., Minneapolis, MN (A.W.C., D.G.); and North Memorial Medical Center, Trauma Services, Robbinsdale, MN (E.D.I.)
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146
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Mark AL, Somers VK. Obesity, Hypoxemia, and Hypertension: Mechanistic Insights and Therapeutic Implications. Hypertension 2016; 68:24-6. [PMID: 27160202 DOI: 10.1161/hypertensionaha.116.07338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Allyn L Mark
- From the Department of Internal Medicine, the Obesity Research and Education Initiative, and the Center for Hypertension Research, University of Iowa Carver College of Medicine, Iowa City (A.L.M.); and Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (V.K.S.).
| | - Virend K Somers
- From the Department of Internal Medicine, the Obesity Research and Education Initiative, and the Center for Hypertension Research, University of Iowa Carver College of Medicine, Iowa City (A.L.M.); and Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (V.K.S.)
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147
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Mirizzi G, Giannoni A, Ripoli A, Iudice G, Bramanti F, Emdin M, Passino C. Prediction of the Chemoreflex Gain by Common Clinical Variables in Heart Failure. PLoS One 2016; 11:e0153510. [PMID: 27099934 PMCID: PMC4839709 DOI: 10.1371/journal.pone.0153510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/30/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Peripheral and central chemoreflex sensitivity, assessed by the hypoxic or hypercapnic ventilatory response (HVR and HCVR, respectively), is enhanced in heart failure (HF) patients, is involved in the pathophysiology of the disease, and is under investigation as a potential therapeutic target. Chemoreflex sensitivity assessment is however demanding and, therefore, not easily applicable in the clinical setting. We aimed at evaluating whether common clinical variables, broadly obtained by routine clinical and instrumental evaluation, could predict increased HVR and HCVR. METHODS AND RESULTS 191 patients with systolic HF (left ventricular ejection fraction--LVEF--<50%) underwent chemoreflex assessment by rebreathing technique to assess HVR and HCVR. All patients underwent clinical and neurohormonal evaluation, comprising: echocardiogram, cardiopulmonary exercise test (CPET), daytime cardiorespiratory monitoring for breathing pattern evaluation. Regarding HVR, multivariate penalized logistic regression, Bayesian Model Averaging (BMA) logistic regression and random forest analysis identified, as predictors, the presence of periodic breathing and increased slope of the relation between ventilation and carbon dioxide production (VE/VCO2) during exercise. Again, the above-mentioned statistical tools identified as HCVR predictors plasma levels of N-terminal fragment of proBNP and VE/VCO2 slope. CONCLUSIONS In HF patients, the simple assessment of breathing pattern, alongside with ventilatory efficiency during exercise and natriuretic peptides levels identifies a subset of patients presenting with increased chemoreflex sensitivity to either hypoxia or hypercapnia.
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Affiliation(s)
- Gianluca Mirizzi
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
- * E-mail:
| | - Alberto Giannoni
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Andrea Ripoli
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Giovanni Iudice
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Francesca Bramanti
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Michele Emdin
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
- Scuola Superiore Sant’Anna, Pisa, Italy
| | - Claudio Passino
- Department of Cardiology and Cardiovascular Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy
- Scuola Superiore Sant’Anna, Pisa, Italy
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148
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Niewinski P. Carotid body modulation in systolic heart failure from the clinical perspective. J Physiol 2016; 595:53-61. [PMID: 26990354 DOI: 10.1113/jp271692] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 03/10/2016] [Indexed: 01/30/2023] Open
Abstract
Augmented sensitivity of peripheral chemoreceptors (PChS) is a common finding in systolic heart failure (HF). It is related to lower left ventricle systolic function, higher plasma concentrations of natriuretic peptides, worse exercise tolerance and greater prevalence of atrial fibrillation compared to patients with normal PChS. The magnitude of ventilatory response to the activation of peripheral chemoreceptors is proportional to the level of heart rate (tachycardia) and blood pressure (hypertension) responses. All these responses can be measured non-invasively in a safe and reproducible fashion using different methods employing either hypoxia or hypercapnia. Current interventions aimed at modulation of peripheral chemoreceptors in HF are focused on carotid bodies (CBs). There is a clear link between afferent signalling from CBs and sympathetic overactivity, which remains the priority target of modern HF treatment. However, CB modulation therapies may face several potential obstacles: (1) As evidenced by HF trials, an excessive inhibition of sympathetic system may be harmful. (2) Proximity of critical anatomical structures (important vessels and nerves) makes surgical and transcutaneous interventions on CB technically demanding. (3) Co-existence of atherosclerosis in the area of carotid artery bifurcation increases the risk of central embolic events related to CB modulation. (4) The relative contribution of CBs vs. aortic bodies to sympathetic activation in HF patients is unclear. (5) Choosing optimal candidates for CB modulation from the population of HF patients may be problematic. (6) There is a risk of nocturnal hypoxia following CB ablation - mostly after bilateral procedures and in patients with concomitant obstructive sleep apnoea.
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Affiliation(s)
- Piotr Niewinski
- Cardiology Department, Centre for Heart Diseases, Military Hospital, Wroclaw, Poland
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149
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Kim SJ, Kim YJ, Kakall Z, Farnham MMJ, Pilowsky PM. Intermittent hypoxia-induced cardiorespiratory long-term facilitation: A new role for microglia. Respir Physiol Neurobiol 2016; 226:30-8. [PMID: 27015670 DOI: 10.1016/j.resp.2016.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/18/2016] [Accepted: 03/18/2016] [Indexed: 02/07/2023]
Abstract
Intermittent hypoxia induces plasticity in neural networks controlling breathing and cardiovascular function. Studies demonstrate that mechanisms causing cardiorespiratory plasticity rely on intracellular signalling pathways that are activated by specific neurotransmitters. Peptides such as serotonin, PACAP and orexin are well-known for their physiological significance in regulating the cardiorespiratory system. Their receptor counterparts are present in cardiorespiratory centres of the brainstem medulla and spinal cord. Microglial cells are also important players in inducing plasticity. The phenotype and function of microglial cells can change based on the physiological state of the central nervous system. Here, we propose that in the autonomic nuclei of the ventral brainstem the relationship between neurotransmitters and neurokines, neurons and microglia determines the overall neural function of the central cardiorespiratory system.
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Affiliation(s)
- Seung Jae Kim
- Department of Physiology, Faculty of Medicine, The University of Sydney, Sydney, New South Wales 2006, Australia; The Heart Research Institute, 7 Eliza Street, Newtown, Sydney 2042, Australia
| | - Yeon Jae Kim
- Department of Physiology, Faculty of Medicine, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Zohra Kakall
- Department of Physiology, Faculty of Medicine, The University of Sydney, Sydney, New South Wales 2006, Australia; The Heart Research Institute, 7 Eliza Street, Newtown, Sydney 2042, Australia
| | - Melissa M J Farnham
- Department of Physiology, Faculty of Medicine, The University of Sydney, Sydney, New South Wales 2006, Australia; The Heart Research Institute, 7 Eliza Street, Newtown, Sydney 2042, Australia
| | - Paul M Pilowsky
- Department of Physiology, Faculty of Medicine, The University of Sydney, Sydney, New South Wales 2006, Australia; The Heart Research Institute, 7 Eliza Street, Newtown, Sydney 2042, Australia.
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150
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Iturriaga R, Del Rio R, Idiaquez J, Somers VK. Carotid body chemoreceptors, sympathetic neural activation, and cardiometabolic disease. Biol Res 2016; 49:13. [PMID: 26920146 PMCID: PMC4768417 DOI: 10.1186/s40659-016-0073-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/12/2016] [Indexed: 11/10/2022] Open
Abstract
The carotid body (CB) is the main peripheral chemoreceptor that senses the arterial PO2, PCO2 and pH. In response to hypoxemia, hypercapnia and acidosis, carotid chemosensory discharge elicits reflex respiratory, autonomic and cardiovascular adjustments. The classical construct considers the CB as the main peripheral oxygen sensor, triggering reflex physiological responses to acute hypoxemia and facilitating the ventilatory acclimation to chronic hypoxemia at high altitude. However, a growing body of experimental evidence supports the novel concept that an abnormally enhanced CB chemosensory input to the brainstem contributes to overactivation
of the sympathetic nervous system, and consequent pathology. Indeed, the CB has been implicated in several diseases associated with increases in central sympathetic outflow. These include hypertension, heart failure, sleep apnea, chronic obstructive pulmonary disease and metabolic syndrome. Indeed, ablation of the CB has been proposed for the treatment of severe and resistant hypertension in humans. In this review, we will analyze and discuss new evidence supporting an important role for the CB chemoreceptor in the progression of autonomic and cardiorespiratory alterations induced by heart failure, obstructive sleep apnea, chronic obstructive pulmonary disease and metabolic syndrome.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Centro de Investigación Biomédica, Universidad Autónoma de Chile, Santiago, Chile. .,Dirección de Investigación, Universidad Científica del Sur, Lima, Peru.
| | - Juan Idiaquez
- Catedra de Neurología, Escuela de Medicina, Universidad de Valparaíso, Valparaíso, Chile.
| | - Virend K Somers
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
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