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Kataoka Y, Sales ARK, Rodrigues AG, Goes-Santos BR, Azevedo LF, Groehs RV, Silva EO, Santos LS, Oliveira PA, Jordão CP, Andrade ACM, Lobo DML, Rondon E, Toschi-Dias E, Alves MJNN, Almeida DR, Negrão CE. Abnormal neurovascular control during central and peripheral chemoreceptors stimulation in heart failure patients with preserved ejection fraction. Clin Auton Res 2024; 34:363-374. [PMID: 38878143 DOI: 10.1007/s10286-024-01041-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 05/20/2024] [Indexed: 07/19/2024]
Abstract
PURPOSE Central and peripheral chemoreceptors are hypersensitized in patients with heart failure with reduced ejection fraction. Whether this autonomic alteration occurs in patients with heart failure with preserved ejection fraction (HFpEF) remains little known. We test the hypothesis that the central and peripheral chemoreflex control of muscle sympathetic nerve activity (MSNA) is altered in HFpEF. METHODS Patients aged 55-80 years with symptoms of heart failure, body mass index ≤ 35 kg/m2, left ventricular ejection fraction > 50%, left atrial volume index > 34 mL/m2, left ventricular early diastolic filling velocity and early diastolic tissue velocity of mitral annulus ratio (E/e' index) ≥ 13, and BNP levels > 35 pg/mL were included in the study (HFpEF, n = 9). Patients without heart failure with preserved ejection fraction (non-HFpEF, n = 9), aged-paired, were also included in the study. Peripheral chemoreceptors stimulation (10% O2 and 90% N2, with CO2 titrated) and central chemoreceptors stimulation (7% CO2 and 93% O2) were conducted for 3 min. MSNA was evaluated by microneurography technique, and forearm blood flow (FBF) by venous occlusion plethysmography. RESULTS During hypoxia, MSNA responses were greater (p < 0.001) and FBF responses were lower in patients with HFpEF (p = 0.006). Likewise, MSNA responses during hypercapnia were higher (p < 0.001) and forearm vascular conductance (FVC) levels were lower (p = 0.030) in patients with HFpEF. CONCLUSIONS Peripheral and central chemoreflex controls of MSNA are hypersensitized in patients with HFpEF, which seems to contribute to the increase in MSNA in these patients. In addition, peripheral and central chemoreceptors stimulation in patients with HFpEF causes muscle vasoconstriction.
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Affiliation(s)
- Yufuko Kataoka
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Allan R K Sales
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
- D'Or Institute for Research and Education (IDOR), São Paulo, Brazil
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Amanda G Rodrigues
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
- Research and Education Institute, Hospital Sirio Libanes, São Paulo, Brazil
| | - Beatriz R Goes-Santos
- School of Physical Education, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Luciene F Azevedo
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Raphaela V Groehs
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Edna O Silva
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Luciana S Santos
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Patricia A Oliveira
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Camila P Jordão
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Ana C M Andrade
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Denise M L Lobo
- Physiotherapy Unit, Fametro University Center (Unifametro), Fortaleza, Ceará, Brazil
| | - Eduardo Rondon
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Edgar Toschi-Dias
- Psychology, Development and Public Policy Program, Catholic University of Santos, São Paulo, Brazil
| | - Maria Janieire N N Alves
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil
| | - Dirceu R Almeida
- Division of Cardiology, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Carlos E Negrão
- Faculdade de Medicina, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 44, Cerqueira César, São Paulo, CEP 05403-904, Brazil.
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
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Díaz-Jara E, Pereyra K, Vicencio S, Olesen MA, Schwarz KG, Toledo C, Díaz HS, Quintanilla RA, Del Rio R. Superoxide dismutase 2 deficiency is associated with enhanced central chemoreception in mice: Implications for breathing regulation. Redox Biol 2024; 69:102992. [PMID: 38142585 PMCID: PMC10788617 DOI: 10.1016/j.redox.2023.102992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/07/2023] [Indexed: 12/26/2023] Open
Abstract
AIMS In mammals, central chemoreception plays a crucial role in the regulation of breathing function in both health and disease conditions. Recently, a correlation between high levels of superoxide anion (O2.-) in the Retrotrapezoid nucleus (RTN), a main brain chemoreceptor area, and enhanced central chemoreception has been found in rodents. Interestingly, deficiency in superoxide dismutase 2 (SOD2) expression, a pivotal antioxidant enzyme, has been linked to the development/progression of several diseases. Despite, the contribution of SOD2 on O2.- regulation on central chemoreceptor function is unknown. Accordingly, we sought to determine the impact of partial deletion of SOD2 expression on i) O2.-accumulation in the RTN, ii) central ventilatory chemoreflex function, and iii) disordered-breathing. Finally, we study cellular localization of SOD2 in the RTN of healthy mice. METHODS Central chemoreflex drive and breathing function were assessed in freely moving heterozygous SOD2 knockout mice (SOD2+/- mice) and age-matched control wild type (WT) mice by whole-body plethysmography. O2.- levels were determined in RTN brainstem sections and brain isolated mitochondria, while SOD2 protein expression and tissue localization were determined by immunoblot, RNAseq and immunofluorescent staining, respectively. RESULTS Our results showed that SOD2+/- mice displayed reductions in SOD2 levels and high O2.- formation and mitochondrial dysfunction within the RTN compared to WT. Additionally, SOD2+/- mice displayed a heightened ventilatory response to hypercapnia and exhibited overt signs of altered breathing patterns. Both, RNAseq analysis and immunofluorescence co-localization studies showed that SOD2 expression was confined to RTN astrocytes but not to RTN chemoreceptor neurons. Finally, we found that SOD2+/- mice displayed alterations in RTN astrocyte morphology compared to RTN astrocytes from WT mice. INNOVATION & CONCLUSION These findings provide first evidence of the role of SOD2 in the regulation of O2.- levels in the RTN and its potential contribution on the regulation of central chemoreflex function. Our results suggest that reductions in the expression of SOD2 in the brain may contribute to increase O2.- levels in the RTN being the outcome a chronic surge in central chemoreflex drive and the development/maintenance of altered breathing patterns. Overall, dysregulation of SOD2 and the resulting increase in O2.- levels in brainstem respiratory areas can disrupt normal respiratory control mechanisms and contribute to breathing dysfunction seen in certain disease conditions characterized by high oxidative stress.
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Affiliation(s)
- Esteban Díaz-Jara
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Katherine Pereyra
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Sinay Vicencio
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Margrethe A Olesen
- Laboratory of Neurodegenerative Diseases, Universidad Autónoma de Chile, Santiago, Chile.
| | - Karla G Schwarz
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile; Institute of Physiology, Universidad Austral de Chile, Valdivia, Chile.
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Rodrigo A Quintanilla
- Laboratory of Neurodegenerative Diseases, Universidad Autónoma de Chile, Santiago, Chile.
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile; Department of Cell Biology and Physiology, School of Medicine, University of Kansas Medical Center, Kansas City, KS, United States.
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Felippe ISA, Río RD, Schultz H, Machado BH, Paton JFR. Commonalities and differences in carotid body dysfunction in hypertension and heart failure. J Physiol 2023; 601:5527-5551. [PMID: 37747109 PMCID: PMC10873039 DOI: 10.1113/jp284114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023] Open
Abstract
Carotid body pathophysiology is associated with many cardiovascular-respiratory-metabolic diseases. This pathophysiology reflects both hyper-sensitivity and hyper-tonicity. From both animal models and human patients, evidence indicates that amelioration of this pathophysiological signalling improves disease states such as a lowering of blood pressure in hypertension, a reduction of breathing disturbances with improved cardiac function in heart failure (HF) and a re-balancing of autonomic activity with lowered sympathetic discharge. Given this, we have reviewed the mechanisms of carotid body hyper-sensitivity and hyper-tonicity across disease models asking whether there is uniqueness related to specific disease states. Our analysis indicates some commonalities and some potential differences, although not all mechanisms have been fully explored across all disease models. One potential commonality is that of hypoperfusion of the carotid body across hypertension and HF, where the excessive sympathetic drive may reduce blood flow in both models and, in addition, lowered cardiac output in HF may potentiate the hypoperfusion state of the carotid body. Other mechanisms are explored that focus on neurotransmitter and signalling pathways intrinsic to the carotid body (e.g. ATP, carbon monoxide) as well as extrinsic molecules carried in the blood (e.g. leptin); there are also transcription factors found in the carotid body endothelium that modulate its activity (Krüppel-like factor 2). The evidence to date fully supports that a better understanding of the mechanisms of carotid body pathophysiology is a fruitful strategy for informing potential new treatment strategies for many cardiovascular, respiratory and metabolic diseases, and this is highly relevant clinically.
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Affiliation(s)
- Igor S. A. Felippe
- Manaaki Manawa – The Centre for Heart Research, Department of Physiology, Faculty of Health & Medical Sciences, University of Auckland, Grafton, Auckland, 1023, New Zealand
| | - Rodrigo Del Río
- Department of Physiology, Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Harold Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Benedito H. Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Julian F. R. Paton
- Manaaki Manawa – The Centre for Heart Research, Department of Physiology, Faculty of Health & Medical Sciences, University of Auckland, Grafton, Auckland, 1023, New Zealand
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Zawadka-Kunikowska M, Rzepiński Ł, Cieślicka M, Fanslau J, Klawe JJ, Tafil-Klawe M. Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients. Adv Respir Med 2023; 91:546-559. [PMID: 38131875 PMCID: PMC10740449 DOI: 10.3390/arm91060040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/25/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.
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Affiliation(s)
- Monika Zawadka-Kunikowska
- Department of Human Physiology, Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Karłowicza 24, 85-092 Bydgoszcz, Poland; (M.C.); (J.F.); (M.T.-K.)
| | - Łukasz Rzepiński
- Sanitas—Neurology Outpatient Clinic, Dworcowa 110, 85-010 Bydgoszcz, Poland;
- Department of Neurology, 10th Military Research Hospital and Polyclinic, 85-681 Bydgoszcz, Poland
| | - Mirosława Cieślicka
- Department of Human Physiology, Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Karłowicza 24, 85-092 Bydgoszcz, Poland; (M.C.); (J.F.); (M.T.-K.)
| | - Joanna Fanslau
- Department of Human Physiology, Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Karłowicza 24, 85-092 Bydgoszcz, Poland; (M.C.); (J.F.); (M.T.-K.)
| | - Jacek J. Klawe
- Department of Hygiene, Epidemiology, Ergonomy and Postgraduate Education, Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, M. Sklodowskiej-Curie 9, 85-094 Bydgoszcz, Poland;
| | - Małgorzata Tafil-Klawe
- Department of Human Physiology, Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Karłowicza 24, 85-092 Bydgoszcz, Poland; (M.C.); (J.F.); (M.T.-K.)
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D'Souza AW, Takeda R, Manabe K, Hissen SL, Washio T, Coombs GB, Sanchez B, Fu Q, Shoemaker JK. The interactive effects of age and sex on the neuro-cardiovascular responses during fatiguing rhythmic handgrip exercise. J Physiol 2023; 601:2877-2898. [PMID: 37083007 DOI: 10.1113/jp284517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 03/30/2023] [Indexed: 04/22/2023] Open
Abstract
The impact of age on exercise pressor responses is equivocal, likely because of sex-specific neuro-cardiovascular changes with age. However, assessments of the interactive effects of age and sex on muscle sympathetic nerve activity (MSNA) responses to exercise are lacking. We tested the hypothesis that older females would exhibit exaggerated increases in blood pressure (BP) and MSNA discharge patterns during handgrip exercise compared with similarly aged males and young adults. Twenty-five young (25 (2) years; mean (SD)) males (YM; n = 12) and females (YF; n = 13) and 23 older (71 (5) years) males (OM; n = 11) and females (OF; n = 12) underwent assessments of BP, total peripheral resistance (TPR; Modelflow) and MSNA action potential (AP) discharge patterns (microneurography) during incremental rhythmic handgrip exercise and post-exercise circulatory occlusion (PECO). OM demonstrated larger ∆BP and ∆TPR from baseline than YM (both P < 0.001) despite smaller increases in ∆APs/burst (OM: 0.4 (3) vs. YM: 5 (3) spikes/burst, P < 0.001) and ∆AP clusters/burst (OM: 0.1 (1) vs. YM: 1.8 (1) clusters/burst, P < 0.001) during exercise. Testosterone was lower in OM than YM (P < 0.001) and was inversely related to ∆BP but positively related to ∆AP clusters/burst in males (both P = 0.03). Conversely, YF and OF demonstrated similar ∆BP and ∆AP discharge during exercise (range: P = 0.75-0.96). Age and sex did not impact haemodynamics or AP discharge during PECO (range: P = 0.08-0.94). Altogether, age-related changes in neuro-cardiovascular reactivity exist in males but not females during fatiguing exercise and seem to be related to testosterone. This sex-specific impact of age underscores the importance of considering biological sex when assessing age-related changes in neuro-cardiovascular control during exercise. KEY POINTS: Older males have the largest increase in blood pressure despite having the smallest increases in sympathetic vasomotor outflow during rhythmic handgrip exercise. Young males demonstrate greater increases in sympathetic action potential (AP) discharge compared with young females during rhythmic handgrip exercise. Older adults (regardless of sex) demonstrate smaller increases in muscle sympathetic nerve activity (MSNA) burst amplitude and total AP clusters compared with young adults during exercise, as well as smaller increases in integrated MSNA burst frequency, incidence and total MSNA activity during post-exercise circulatory occlusion (i.e. independent effect of age). Males, but not females (regardless of age), reflexively modify AP conduction velocity during exercise. Our results indicate that age and sex independently and interactively impact the neural and cardiovascular homeostatic adjustments to fatiguing small muscle mass exercise.
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Affiliation(s)
- Andrew W D'Souza
- Neurovascular research laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Ryosuke Takeda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kazumasa Manabe
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Sarah L Hissen
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Takuro Washio
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Geoff B Coombs
- Neurovascular research laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Belinda Sanchez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - J Kevin Shoemaker
- Neurovascular research laboratory, School of Kinesiology, Western University, London, Ontario, Canada
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
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Neder JA, Phillips DB, O'Donnell DE, Dempsey JA. Excess ventilation and exertional dyspnoea in heart failure and pulmonary hypertension. Eur Respir J 2022; 60:13993003.00144-2022. [PMID: 35618273 DOI: 10.1183/13993003.00144-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/05/2022] [Indexed: 01/11/2023]
Abstract
Increased ventilation relative to metabolic demands, indicating alveolar hyperventilation and/or increased physiological dead space (excess ventilation), is a key cause of exertional dyspnoea. Excess ventilation has assumed a prominent role in the functional assessment of patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction, pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). We herein provide the key pieces of information to the caring physician to 1) gain unique insights into the seeds of patients' shortness of breath and 2) develop a rationale for therapeutically lessening excess ventilation to mitigate this distressing symptom. Reduced bulk oxygen transfer induced by cardiac output limitation and/or right ventricle-pulmonary arterial uncoupling increase neurochemical afferent stimulation and (largely chemo-) receptor sensitivity, leading to alveolar hyperventilation in HFrEF, PAH and small-vessel, distal CTEPH. As such, interventions geared to improve central haemodynamics and/or reduce chemosensitivity have been particularly effective in lessening their excess ventilation. In contrast, 1) high filling pressures in HFpEF and 2) impaired lung perfusion leading to ventilation/perfusion mismatch in proximal CTEPH conspire to increase physiological dead space. Accordingly, 1) decreasing pulmonary capillary pressures and 2) mechanically unclogging larger pulmonary vessels (pulmonary endarterectomy and balloon pulmonary angioplasty) have been associated with larger decrements in excess ventilation. Exercise training has a strong beneficial effect across diseases. Addressing some major unanswered questions on the link of excess ventilation with exertional dyspnoea under the modulating influence of pharmacological and nonpharmacological interventions might prove instrumental to alleviate the devastating consequences of these prevalent diseases.
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Affiliation(s)
- J Alberto Neder
- Clinical Exercise Physiology and Respiratory Investigation Unit, Division of Respiratory and Critical Care Medicine, Dept of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Devin B Phillips
- Clinical Exercise Physiology and Respiratory Investigation Unit, Division of Respiratory and Critical Care Medicine, Dept of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Denis E O'Donnell
- Clinical Exercise Physiology and Respiratory Investigation Unit, Division of Respiratory and Critical Care Medicine, Dept of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, Dept of Population Health Sciences, University of Wisconsin-Madison, Madison, WI, USA
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Toledo C, Díaz-Jara E, Diaz HS, Schwarz KG, Pereyra KV, Las Heras A, Rios-Gallardo A, Andrade DC, Moreira T, Takakura A, Marcus NJ, Del Rio R. Medullary astrocytes mediate irregular breathing patterns generation in chronic heart failure through purinergic P2X7 receptor signalling. EBioMedicine 2022; 80:104044. [PMID: 35533501 PMCID: PMC9097632 DOI: 10.1016/j.ebiom.2022.104044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/05/2022] Open
Abstract
Background Breathing disorders (BD) (apnoeas/hypopneas, periodic breathing) are highly prevalent in chronic heart failure (CHF) and are associated with altered central respiratory control. Ample evidence identifies the retrotrapezoid nucleus (RTN) as an important chemosensitivity region for ventilatory control and generation of BD in CHF, however little is known about the cellular mechanisms underlying the RTN/BD relationship. Within the RTN, astrocyte‐mediated purinergic signalling modulates respiration, but the potential contribution of RTN astrocytes to BD in CHF has not been explored. Methods Selective neuron and/or astrocyte-targeted interventions using either optogenetic and chemogenetic manipulations in the RTN of CHF rats were used to unveil the contribution of the RTN on the development/maintenance of BD, the role played by astrocytes in BD and the molecular mechanism underpinning these alterations. Findings We showed that episodic photo-stimulation of RTN neurons triggered BD in healthy rats, and that RTN neurons ablation in CHF animals eliminates BD. Also, we found a reduction in astrocytes activity and ATP bioavailability within the RTN of CHF rats, and that chemogenetic restoration of normal RTN astrocyte activity and ATP levels improved breathing regularity in CHF. Importantly, P"X/ P2X7 receptor (P2X7r) expression was reduced in RTN astrocytes from CHF rats and viral vector-mediated delivery of human P2X7 P2X7r into astrocytes increases ATP bioavailability and abolished BD. Interpretation Our results support that RTN astrocytes play a pivotal role on BD generation and maintenance in the setting CHF by a mechanism encompassing P2X7r signalling. Funding This study was funded by the National Research and Development Agency of Chile (ANID).
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Sayegh ALC, Fan JL, Vianna LC, Dawes M, Paton JFR, Fisher JP. Sex-differences in the sympathetic neurocirculatory responses to chemoreflex activation. J Physiol 2022; 600:2669-2689. [PMID: 35482235 PMCID: PMC9324851 DOI: 10.1113/jp282327] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 04/25/2022] [Indexed: 11/08/2022] Open
Abstract
Abstract The purpose of this study was to determine whether there are sex differences in the cardiorespiratory and sympathetic neurocirculatory responses to central, peripheral, and combined central and peripheral chemoreflex activation. Ten women (29 ± 6 years, 22.8 ± 2.4 kg/m2: mean ± SD) and 10 men (30 ± 7 years, 24.8 ± 3.2 kg/m2) undertook randomized 5 min breathing trials of: room air (eucapnia), isocapnic hypoxia (10% oxygen (O2); peripheral chemoreflex activation), hypercapnic hyperoxia (7% carbon dioxide (CO2), 50% O2; central chemoreflex activation) and hypercapnic hypoxia (7% CO2, 10% O2; central and peripheral chemoreflex activation). Control trials of isocapnic hyperoxia (peripheral chemoreflex inhibition) and hypocapnic hyperoxia (central and peripheral chemoreflex inhibition) were also included. Muscle sympathetic nerve activity (MSNA; microneurography), mean arterial pressure (MAP; finger photoplethysmography) and minute ventilation (V˙E; pneumotachometer) were measured. Total MSNA (P = 1.000 and P = 0.616), MAP (P = 0.265) and V˙E (P = 0.587 and P = 0.472) were not different in men and women during eucapnia and during isocapnic hypoxia. Women exhibited attenuated increases in V˙E during hypercapnic hyperoxia (27.3 ± 6.3 vs. 39.5 ± 7.5 l/min, P < 0.0001) and hypercapnic hypoxia (40.9 ± 9.1 vs. 53.8 ± 13.3 l/min, P < 0.0001) compared with men. However, total MSNA responses were augmented in women (hypercapnic hyperoxia 378 ± 215 vs. 258 ± 107%, P = 0.017; hypercapnic hypoxia 607 ± 290 vs. 362 ± 268%, P < 0.0001). No sex differences in total MSNA, MAP or V˙E were observed during isocapnic hyperoxia and hypocapnic hyperoxia. Our results indicate that young women have augmented sympathetic responses to central chemoreflex activation, which explains the augmented MSNA response to combined central and peripheral chemoreflex activation. Key points Sex differences in the control of breathing have been well studied, but whether there are differences in the sympathetic neurocirculatory responses to chemoreflex activation between healthy women and men is incompletely understood. We observed that, compared with young men, young women displayed augmented increases in muscle sympathetic nerve activity during both hypercapnic hyperoxia (central chemoreflex activation) and hypercapnic hypoxia (central and peripheral chemoreflex activation) but had attenuated increases in minute ventilation. In contrast, no sex differences were found in either muscle sympathetic nerve activity or minute ventilation responses to isocapnic hypoxia (peripheral chemoreceptor stimulation). Young women have blunted ventilator, but augmented sympathetic responses, to central (hypercapnic hyperoxia) and combined central and peripheral chemoreflex activation (hypercapnic hypoxia), compared with young men. The possible causative association between the reduced ventilation and heightened sympathetic responses in young women awaits validation.
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Affiliation(s)
- Ana Luiza C Sayegh
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - Jui-Lin Fan
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, DF, Brazil
| | - Mathew Dawes
- Department of Medicine, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - Julian F R Paton
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - James P Fisher
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
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9
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Moriyama S, Ichinose M, Dobashi K, Matsutake R, Sakamoto M, Fujii N, Nishiyasu T. Hypercapnia elicits differential vascular and blood flow responses in the cerebral circulation and active skeletal muscles in exercising humans. Physiol Rep 2022; 10:e15274. [PMID: 35466573 PMCID: PMC9035754 DOI: 10.14814/phy2.15274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 03/29/2022] [Indexed: 12/02/2022] Open
Abstract
The purpose of this study was to investigate the effects of a rise in arterial carbon dioxide pressure (PaCO2) on vascular and blood flow responses in the cerebral circulation and active skeletal muscles during dynamic exercise in humans. Thirteen healthy young adults (three women) participated in hypercapnia and normocapnia trials. In both trials, participants performed a two‐legged dynamic knee extension exercise at a constant workload that increased heart rate to roughly 100 beats min−1. In the hypercapnia trial, participants performed the exercise with spontaneous breathing while end‐tidal carbon dioxide pressure (PETCO2), an index of PaCO2, was held at 60 mmHg by inhaling hypercapnic gas (O2: 20.3 ± 0.1%; CO2: 6.0 ± 0.5%). In the normocapnia trial, minute ventilation during exercise was matched to the value in the hypercapnia trial by performing voluntary hyperventilation with PETCO2 clamped at baseline level (i.e., 40–45 mmHg) through inhalation of mildly hypercapnic gas (O2: 20.6 ± 0.1%; CO2: 2.7 ± 1.0%). Middle cerebral artery mean blood velocity and the cerebral vascular conductance index were higher in the hypercapnia trial than in the normocapnia trial. By contrast, vascular conductance in the exercising leg was lower in the hypercapnia trial than in the normocapnia trial. Blood flow to the exercising leg did not differ between the two trials. These results demonstrate that hypercapnia‐induced vasomotion in active skeletal muscles is opposite to that in the cerebral circulation. These differential vascular responses may cause a preferential rise in cerebral blood flow.
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Affiliation(s)
- Shodai Moriyama
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Ibaraki Japan
| | - Masashi Ichinose
- Human Integrative Physiology Laboratory School of Business Administration Meiji University Tokyo Japan
| | - Kohei Dobashi
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Ibaraki Japan
- Faculty of Education Hokkaido University of Education Hokkaido Japan
| | - Ryoko Matsutake
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Ibaraki Japan
| | - Mizuki Sakamoto
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Ibaraki Japan
| | - Naoto Fujii
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Ibaraki Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Ibaraki Japan
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10
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Javaheri S, Germany R. Sleep and breathing disorders in heart failure. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:295-307. [PMID: 36031310 DOI: 10.1016/b978-0-323-91532-8.00009-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Sleep disorders are prevalent in heart failure and include insomnia, poor sleep architecture, periodic limb movements and periodic breathing, and encompass both obstructive (OSA) and central sleep apnea (CSA). Polysomnographic studies show excess light sleep and poor sleep efficiency particularly in those with heart failure. Multiple studies of consecutive patients with heart failure show that about 50% of patients suffer from either OSA or CSA. While asleep, acute pathological consequences of apneas and hypopneas include altered blood gases, sleep fragmentation, and large negative swings in intrathoracic pressure. These pathological consequences are qualitatively similar in both types of sleep apnea, though worse in OSA than CSA. Sleep apnea results in oxidative stress, inflammation, and endothelial dysfunction, best documented in OSA. Multiple studies show that both OSA and CSA are associated with excess hospital readmissions and premature mortality. However, no randomized controlled trial (RCT) has been reported for OSA, but sensitivity analysis of two randomized controlled trials has concluded that use of positive airway pressure devices is associated with excess mortality in patients with heart failure and CSA. Phrenic nerve stimulation has shown improvement in sleep apnea events and daytime sleepiness; however, no randomized controlled trials have demonstrated improvement in survival in patients with heart failure. The correct identification and treatment of heart failure patients with sleep and breathing disorders could affect the long-term outcomes of these patients.
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Affiliation(s)
- Shahrokh Javaheri
- Division of Pulmonary and Sleep Medicine, Bethesda North Hospital, Cincinnati, OH, United States; Division of Pulmonary, Critical Care and Sleep Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States; Division of Cardiology, Ohio State University, Columbus, OH, United States.
| | - Robin Germany
- Division of Cardiovascular Disease, University of Oklahoma College of Medicine, Oklahoma City, OK, United States
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11
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Wang X, Luo J, Huang R, Xiao Y. The Elevated Central Chemosensitivity in Obstructive Sleep Apnea Patients with Hypertension. Nat Sci Sleep 2022; 14:855-865. [PMID: 35547180 PMCID: PMC9081185 DOI: 10.2147/nss.s362319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/20/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Hypertension is a common comorbidity in obstructive sleep apnea (OSA), in which dysfunction of the autonomic nervous system plays an integral part. Chemoreflex is essential for ventilatory control and cardiovascular activity. This study aimed to determine whether central chemosensitivity was increased in OSA patients with hypertension and the potential role of the autonomic nerve activity in this relationship. PATIENTS AND METHODS A total of 77 men with OSA were included in this cross-sectional study. We measured hypercapnic ventilatory response (HCVR) by the rebreathing method under isoxic hyperoxia to test the central ventilatory chemosensitivity since hyperoxia silences the peripheral chemoreceptors' response to CO2. To elevate the autonomic nerve activity, time-domain, frequency-domain, and non-linear variables of heart rate variability were calculated over 5-min records. Univariate and multivariate linear regression analyses were used to find the determinants of HCVR. RESULTS The median HCVR was 2.3 (1.8, 3.3), 2.1 (1.6, 3.0), and 3 (2.2, 3.7) L/min/mmHg in all participants, OSA patients, and OSA patients with hypertension, respectively. Hypertension was significantly associated with elevated HCVR after adjusting for age, central obesity, OSA severity, daytime sleepiness, and diabetes mellitus. Compared with OSA patients, OSA patients with hypertension had higher body mass index, worse nocturnal hypoxia, and lower time-domain variables and frequency-domain variables. After adjusting for age, apnea-hypopnea index, central obesity, and beta-blocker usage, approximate entropy was independently negatively associated with HCVR in OSA patients with hypertension. CONCLUSION This study demonstrated elevated central chemosensitivity in OSA patients with hypertension. Compared with OSA patients, OSA patients with hypertension had attenuated parasympathetic nerve activity. This study preliminarily illustrated that elevated central chemosensitivity might be associated with weak adaptability of the cardiac autonomic nervous system in OSA patients with hypertension.
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Affiliation(s)
- Xiaona Wang
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Jinmei Luo
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Rong Huang
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Yi Xiao
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
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12
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Díaz-Jara E, Díaz HS, Rios-Gallardo A, Ortolani D, Andrade DC, Toledo C, Pereyra KV, Schwarz K, Ramirez G, Ortiz FC, Andía ME, Del Rio R. Exercise training reduces brainstem oxidative stress and restores normal breathing function in heart failure. Free Radic Biol Med 2021; 172:470-481. [PMID: 34216779 DOI: 10.1016/j.freeradbiomed.2021.06.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 10/21/2022]
Abstract
Enhanced central chemoreflex drive and irregular breathing are both hallmarks in heart failure (HF) and closely related to disease progression. Central chemoreceptor neurons located within the retrotrapezoid nucleus (RTN) are known to play a role in breathing alterations in HF. It has been shown that exercise (EX) effectively reduced reactive oxygen species (ROS) in HF rats. However, the link between EX and ROS, particularly at the RTN, with breathing alterations in HF has not been previously addressed. Accordingly, we aimed to determine: i) ROS levels in the RTN in HF and its association with chemoreflex drive, ii) whether EX improves chemoreflex/breathing function by reducing ROS levels, and iii) determine molecular alterations associated with ROS generation within the RTN of HF rats and study EX effects on these pathways. Adult male Sprague-Dawley rats were allocated into 3 experimental groups: Sham (n = 5), volume overloaded HF (n = 6) and HF (n = 8) rats that underwent EX training for 6 weeks (60 min/day, 25 m/min, 10% inclination). At 8 weeks post-HF induction, breathing patterns and chemoreflex function were analyzed by unrestrained plethysmography. ROS levels and anti/pro-oxidant enzymes gene expression were analyzed in the RTN. Our results showed that HF rats have high ROS levels in the RTN which were closely linked to the enhanced central chemoreflex and breathing disorders. Also, HF rats displayed decreased expression of antioxidant genes in the RTN compared with control rats. EX training increases antioxidant defense in the RTN, reduces ROS formation and restores normal central chemoreflex drive and breathing regularity in HF rats. This study provides evidence for a role of ROS in central chemoreception in the setting of HF and support the use of EX to reduce ROS in the brainstem of HF animals and reveal its potential as an effective mean to normalize chemoreflex and breathing function in HF.
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Affiliation(s)
- Esteban Díaz-Jara
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
| | - Angélica Rios-Gallardo
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, 621-0427, Punta Arenas, Chile.
| | - Domiziana Ortolani
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile; Centro de Fisiología y Medicina de Altura, Facultad de Ciencias de la Salud, Universidad de Antofagasta, 1270300, Antofagasta, Chile.
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, 621-0427, Punta Arenas, Chile.
| | - Katherin V Pereyra
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
| | - Karla Schwarz
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
| | - Gigliola Ramirez
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
| | - Fernando C Ortiz
- Centro de Investigación Biomédica, Universidad Autónoma de Chile, Santiago, Chile.
| | - Marcelo E Andía
- Radiology Department & ANID - Millennium Nucleus for Cardiovascular Magnetic Resonance, 8331150, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, 621-0427, Punta Arenas, Chile; Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile, 8331150, Santiago, Chile.
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13
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Grassi G, Mancia G, Esler M. CENTRAL AND PERIPHERAL SYMPATHETIC ACTIVATION IN HEART FAILURE. Cardiovasc Res 2021; 118:1857-1871. [PMID: 34240147 DOI: 10.1093/cvr/cvab222] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/02/2021] [Indexed: 11/12/2022] Open
Abstract
The sympathetic nervous system overdrive occurring in heart failure has been reported since more than half a century. Refinements in the methodological approaches to assess human sympathetic neural function have allowed during recent years to better define various aspects related to the neuroadrenergic alteration. These include 1) the different participation of the individual regional sympathetic cardiovascular districts at the process, 2) the role of the central nervous system in determining the neuroadrenergic overdrive, 3) the involvement of baroreflex, cardiopulmonary reflex and chemoreflex mechanisms in the phoenomenon, which is also closely linked to inflammation and the immune reaction, 4) the relationships with the severity of the disease, its ischaemic or idiopathic nature and the preserved or reduced left ventricular ejection fraction and 5) the adverse functional and structural impact of the sympathetic activation on cardiovascular organs, such as the brain, the heart and the kidneys. Information have been also gained on the active role exerted by the sympathetic activation on the disease outcome and its potential relevance as target of the therapeutic interventions based on non-pharmacological, pharmacological and invasive approaches, including the renal denervation, the splanchnic sympathetic nerve ablation and the carotid baroreflex stimulation. The still undefined aspects of the neurogenic alterations and the unmet goals of the therapeutic approach having the sympathetic activation as a target of the intervention will be finally mentioned.
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Affiliation(s)
- Guido Grassi
- Clinica Medica, Department of Medicine and Surgery, University of Milano-Bicocca
| | - Giuseppe Mancia
- Policlinico di Monza and University Milano-Bicocca, Milan, Italy
| | - Murray Esler
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
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14
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Pachen M, Abukar Y, Shanks J, Lever N, Ramchandra R. Regulation of Coronary Blood Flow by the Carotid Body Chemoreceptors in Ovine Heart Failure. Front Physiol 2021; 12:681135. [PMID: 34122147 PMCID: PMC8195281 DOI: 10.3389/fphys.2021.681135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 04/26/2021] [Indexed: 11/17/2022] Open
Abstract
Carotid bodies (CBs) are peripheral chemoreceptors, which are primary sensors of systemic hypoxia and their activation produces respiratory, autonomic, and cardiovascular adjustments critical for body homeostasis. We have previously shown that carotid chemoreceptor stimulation increases directly recorded cardiac sympathetic nerve activity (cardiac SNA) which increases coronary blood flow (CoBF) in conscious normal sheep. Previous studies have shown that chemoreflex sensitivity is augmented in heart failure (HF). We hypothesized that carotid chemoreceptor stimulation would increase CoBF to a greater extent in HF than control sheep. Experiments were conducted in conscious HF sheep and control sheep (n = 6/group) implanted with electrodes to record diaphragmatic electromyography (dEMG), flow probes to record CoBF as well as arterial pressure. There was a significant increase in mean arterial pressure (MAP), CoBF and coronary vascular conductance (CVC) in response to potassium cyanide (KCN) in both groups of sheep. To eliminate the effects of metabolic vasodilation, the KCN was repeated while the heart was paced at a constant level. In this paradigm, the increase in CoBF and CVC was augmented in the HF group compared to the control group. Pre-treatment with propranolol did not alter the CoBF or the CVC increase in the HF group indicating this was not mediated by an increase in cardiac sympathetic drive. The pressor response to CB activation was abolished by pre-treatment with intravenous atropine in both groups, but there was no change in the CoBF and vascular conductance responses. Our data suggest that in an ovine model of HF, carotid body (CB) mediated increases in CoBF and CVC are augmented compared to control animals. This increase in CoBF is mediated by an increase in cardiac SNA in the control group but not the HF group.
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Affiliation(s)
- Mridula Pachen
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Yonis Abukar
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Julia Shanks
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Nigel Lever
- Department of Medicine, University of Auckland and Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand
| | - Rohit Ramchandra
- Department of Physiology, University of Auckland, Auckland, New Zealand
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15
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Effect of exercise on endothelial function in heart transplant recipients: systematic review and meta-analysis. Heart Fail Rev 2021; 25:487-494. [PMID: 31808028 DOI: 10.1007/s10741-019-09877-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Endothelial dysfunction is associated with increased cardiovascular risk and death in heart transplant recipients (HTx). Although the measurement of peripheral endothelial function is considered a significant predictor of cardiovascular events in several populations, few studies have investigated this outcome after therapeutic strategies, including different exercise types, duration, and intensity. This systematic review and meta-analysis aimed to investigate the effects of continuous moderate exercise (CON) or high-intensity interval training (HIIT) to improve endothelial function (EF) in HTx. The search was conducted in Cochrane Central Registry of Controlled Trials (CENTRAL), MEDLINE (via PubMed), Web of Science and Scopus/Elsevier, CINAHL/Ebsco, Physiotherapy Evidence Database (PEDro), LILACS/BIREME, and SciELO databases. Quality of the evidence was assessed using the Grading of Recommendations Assessment Development and Evaluation (GRADE). The search strategy retrieved 5192 titles. A total of four articles met the inclusion criteria and were included for the qualitative analysis. Meta-analysis showed that exercises improved EF ([mean difference-MD] 3.48 95% CI - 0.29 to 7.25, p = 0.007) when compared with the control. However, there was a poor quality of evidence to demonstrate that CON or HIIT is better than usual care to improve EF. Exercise training provides benefits to patients, but the poor quality of evidence does not allow us to state that exercise is related to endothelial function improvement in HTx.
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16
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Phillips DB, Domnik NJ, Elbehairy AF, Preston ME, Milne KM, James MD, Vincent SG, Ibrahim-Masthan M, Neder JA, O’Donnell DE. Elevated exercise ventilation in mild COPD is not linked to enhanced central chemosensitivity. Respir Physiol Neurobiol 2021; 284:103571. [DOI: 10.1016/j.resp.2020.103571] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/27/2020] [Accepted: 11/01/2020] [Indexed: 11/25/2022]
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17
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Keir DA, Duffin J, Floras JS. Measuring Peripheral Chemoreflex Hypersensitivity in Heart Failure. Front Physiol 2020; 11:595486. [PMID: 33447244 PMCID: PMC7802759 DOI: 10.3389/fphys.2020.595486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/30/2020] [Indexed: 01/08/2023] Open
Abstract
Heart failure with reduced ejection fraction (HFrEF) induces chronic sympathetic activation. This disturbance is a consequence of both compensatory reflex disinhibition in response to lower cardiac output and patient-specific activation of one or more excitatory stimuli. The result is the net adrenergic output that exceeds homeostatic need, which compromises cardiac, renal, and vascular function and foreshortens lifespan. One such sympatho-excitatory mechanism, evident in ~40-45% of those with HFrEF, is the augmentation of carotid (peripheral) chemoreflex ventilatory and sympathetic responsiveness to reductions in arterial oxygen tension and acidosis. Recognition of the contribution of increased chemoreflex gain to the pathophysiology of HFrEF and to patients' prognosis has focused attention on targeting the carotid body to attenuate sympathetic drive, alleviate heart failure symptoms, and prolong life. The current challenge is to identify those patients most likely to benefit from such interventions. Two assumptions underlying contemporary test protocols are that the ventilatory response to acute hypoxic exposure quantifies accurately peripheral chemoreflex sensitivity and that the unmeasured sympathetic response mirrors the determined ventilatory response. This Perspective questions both assumptions, illustrates the limitations of conventional transient hypoxic tests for assessing peripheral chemoreflex sensitivity and demonstrates how a modified rebreathing test capable of comprehensively quantifying both the ventilatory and sympathoneural efferent responses to peripheral chemoreflex perturbation, including their sensitivities and recruitment thresholds, can better identify individuals most likely to benefit from carotid body intervention.
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Affiliation(s)
- Daniel A. Keir
- University Health Network and Mount Sinai Hospital Division of Cardiology and Department of Medicine, University of Toronto, Toronto General Research Institute, Toronto, ON, Canada
- School of Kinesiology, The University of Western Ontario, London, ON, Canada
| | - James Duffin
- Department of Anesthesia and Pain Management, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Thornhill Research Inc., Toronto, ON, Canada
| | - John S. Floras
- University Health Network and Mount Sinai Hospital Division of Cardiology and Department of Medicine, University of Toronto, Toronto General Research Institute, Toronto, ON, Canada
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18
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Rahman AA, Stojanovska V, Pilowsky P, Nurgali K. Platinum accumulation in the brain and alteration in the central regulation of cardiovascular and respiratory functions in oxaliplatin-treated rats. Pflugers Arch 2020; 473:107-120. [PMID: 33074398 DOI: 10.1007/s00424-020-02480-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 09/18/2020] [Accepted: 10/14/2020] [Indexed: 11/29/2022]
Abstract
Oxaliplatin is a platinum-based alkylating chemotherapeutic agent used for cancer treatment. Neurotoxicity is one of its major adverse effects that often demands dose limitation. However, the effects of chronic oxaliplatin on the toxicity of the autonomic nervous system regulating cardiorespiratory function and adaptive reflexes are unknown. Male Sprague Dawley rats were treated with intraperitoneal oxaliplatin (3 mg kg-1 per dose) 3 times a week for 14 days. The effects of chronic oxaliplatin treatment on baseline mean arterial pressure (MAP); heart rate (HR); splanchnic sympathetic nerve activity (sSNA); phrenic nerve activity (PNA) and its amplitude (PNamp) and frequency (PNf); and sympathetic reflexes were investigated in anaesthetised, vagotomised and artificially ventilated rats. The same parameters were evaluated after acute oxaliplatin injection, and in the chronic treatment group following a single dose of oxaliplatin. The amount of platinum in the brain was determined with atomic absorption spectrophotometry. Chronic oxaliplatin treatment significantly increased MAP, sSNA and PNf and decreased HR and PNamp, while acute oxaliplatin had no effects. Platinum was accumulated in the brain after chronic oxaliplatin treatment. In the chronic oxaliplatin treatment group, further administration of a single dose of oxaliplatin increased MAP and sSNA. The baroreceptor sensitivity and somatosympathetic reflex were attenuated at rest while the sympathoexcitatory response to hypercapnia was increased in the chronic treatment group. This is the first study to reveal oxaliplatin-induced alterations in the central regulation of cardiovascular and respiratory functions as well as reflexes that may lead to hypertension and breathing disorders which may be mediated via accumulated platinum in the brain.
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Affiliation(s)
- Ahmed A Rahman
- College of Health and Biomedicine, Institute for Health and Sport, Victoria University, Melbourne, Australia.,Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Vanesa Stojanovska
- College of Health and Biomedicine, Institute for Health and Sport, Victoria University, Melbourne, Australia.,Hudson Institute of Medical Research, Monash Health Translation Precinct, Melbourne, Australia
| | - Paul Pilowsky
- Heart Research Institute, Central Clinical School, The University of Sydney, Sydney, Australia
| | - Kulmira Nurgali
- College of Health and Biomedicine, Institute for Health and Sport, Victoria University, Melbourne, Australia. .,Department of Medicine Western Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia. .,Regenerative Medicine and Stem Cells Program, Australian Institute of Musculoskeletal Science (AIMSS), Melbourne, Australia. .,Enteric Neuropathy Lab, Western Centre for Health, Research & Education, Sunshine Hospital, 176 Furlong Road, St Albans, Melbourne, Victoria, 3021, Australia.
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Prasad B, Morgan BJ, Gupta A, Pegelow DF, Teodorescu M, Dopp JM, Dempsey JA. The need for specificity in quantifying neurocirculatory vs. respiratory effects of eucapnic hypoxia and transient hyperoxia. J Physiol 2020; 598:4803-4819. [PMID: 32770545 DOI: 10.1113/jp280515] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 08/04/2020] [Indexed: 12/24/2022] Open
Abstract
KEY POINTS The carotid chemoreceptor mediates the ventilatory and muscle sympathetic nerve activity (MSNA) responses to hypoxia and contributes to tonic sympathetic and respiratory drives. It is often presumed that both excitatory and inhibitory tests of chemoreflex function show congruence in the end-organ responses. Ventilatory and neurocirculatory (MSNA, blood pressure and heart rate) responses to chemoreflex inhibition elicited by transient hyperoxia and to chemoreflex excitation produced by steady-state eucapnic hypoxia were measured in a cohort of 82 middle-aged individuals. Ventilatory and MSNA responsiveness to hyperoxia and hypoxia were not significantly correlated within individuals. It was concluded that ventilatory responses to hypoxia and hyperoxia do not predict MSNA responses and it is recommended that tests using the specific outcome of interest, i.e. MSNA or ventilation, are required. Transient hyperoxia is recommended as a sensitive and reliable means of quantifying tonic chemoreceptor-driven levels of sympathetic nervous system activity and respiratory drive. ABSTRACT Hypersensitivity of the carotid chemoreceptor leading to sympathetic nervous system activation and ventilatory instability has been implicated in the pathogenesis and consequences of several common clinical conditions. A variety of treatment approaches aimed at lessening chemoreceptor-driven sympathetic overactivity are now under investigation; thus, the ability to quantify this outcome variable with specificity and precision is crucial. Accordingly, we measured ventilatory and neurocirculatory responses to chemoreflex inhibition elicited by transient hyperoxia and chemoreflex excitation produced by exposure to graded, steady-state eucapnic hypoxia in middle-aged men and women (n = 82) with continuous positive airway pressure-treated obstructive sleep apnoea. Progressive, eucapnic hypoxia produced robust and highly variable increases in ventilation (+83 ± 59%) and muscle sympathetic nerve activity (MSNA) burst frequency (+55 ± 31%), whereas transient hyperoxia caused marked reductions in these variables (-35 ± 14% and -42 ± 16%, respectively). Coefficients of variation for ventilatory and MSNA burst frequency responses, indicating test-retest reproducibility, were respectively 9% and 24% for hyperoxia and 35% and 28% for hypoxia. Based on statistical measures of rank correlation or even comparisons across quartiles of corresponding ventilatory and MSNA responses, we found that the magnitudes of ventilatory inhibition with hyperoxia or excitation with eucapnic hypoxia were not correlated with corresponding MSNA responses within individuals. We conclude that, in conscious, behaving humans, ventilatory sensitivities to progressive, steady-state, eucapnic hypoxia and transient hyperoxia do not predict MSNA responsiveness. Our findings also support the use of transient hyperoxia as a reliable, sensitive, measure of the carotid chemoreceptor contribution to tonic sympathetic nervous system activity and respiratory drive.
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Affiliation(s)
- Bharati Prasad
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Barbara J Morgan
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.,Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Ahana Gupta
- GPPA Medical Scholars Program, University of Illinois at Chicago, Chicago, IL, USA
| | - David F Pegelow
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Mihaela Teodorescu
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - John M Dopp
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | - Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.,Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, WI, USA
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20
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Cherneva RV, Denchev SV, Cherneva ZV. The link between dynamic hyperinflation, autonomic dysfunction and exercise testing parameters with masked heart failure in patients with non-severe obstructive pulmonary disease. J Basic Clin Physiol Pharmacol 2020; 32:179-188. [PMID: 32658862 DOI: 10.1515/jbcpp-2019-0311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/20/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVES Autonomic dysfunction (AD) and dynamic hyperinflation (DH) have been implicated as pathophysiological mechanisms of heart failure with preserved ejection fraction (HFpEF) in chronic obstructive pulmonary disease (COPD) patients. Their association, however, remains elusive: The aims of the study were: (1) to determine the prevalence of AD and DH in non-severe COPD patients, with exertional dyspnea, without clinically overt cardio-vascular (CV) comorbidities; (2) to analyze the correlation and clinical significance between DH, AD, and maksed HFpEF. METHODS We applied CPET in 68 subjects. Echocardiography was performed before CPET and 1-2 min after peak exercise. IC manoeuvres were applied. Patients were divided into two groups: patients with and without masked HFpEF. Wilkoff method calculated the meatabolic - chronotropic relationship (MCR). Chronotropic incompetence (CI) and abnormal HR recovery (HRR) were determined. RESULTS The prevalence of CI was 77 vs. 52% in patients with/without masked HFpEF; of abnormal HRR - 98 vs. 62% respectively; of DH - 53 vs. 29%. ICdyn was associated with AD. Univariate regression showed association between masked HFpEF, ICdyn, HRR, oxygenuptake ('VO2), 'VO2 at anaerobic threshold, oxygen (O2) pulse and 'VE/'VCO2 slope. None of these parameters is an independent predictor for masked HFpEF. CONCLUSIONS DH, AD, and masked HFpEF are prevalent in non-severe COPD patients, who complain of exertional dyspnea and are free of clinically overt CV comorbidities. DH is independently associated with AD. Neither AD, nor DH and CPET are independent predictors for masked HFpEF.
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Affiliation(s)
- Radostina Vl Cherneva
- University Hospital for Respiratory Diseases "St. Sophia'', Han Presian 17, Sofia, Bulgaria
| | | | - Zheina Vl Cherneva
- Medical Institute of the Ministry of Internal Affairs, Gen Skobelev 79, Sofia, Bulgaria
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21
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Sympathetic neural overdrive in congestive heart failure and its correlates: systematic reviews and meta-analysis. J Hypertens 2020; 37:1746-1756. [PMID: 30950979 DOI: 10.1097/hjh.0000000000002093] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND OBJECTIVES Sympathetic neural activation occurs in congestive heart failure (CHF). However, the small sample size of the microneurographic studies, heterogeneity of the patients examined, presence of comorbidities as well as confounders (including treatment) represented major weaknesses not allowing to identify the major features of the phoenomenon, particularly in mild CHF. This meta-analysis evaluated 2530 heart failure (CHF) patients recruited in 106 microneurographic studies. It was based on muscle sympathetic nerve activity (MSNA) quantification in CHF of different clinical severity, but data from less widely addressed conditions, such as ischemic vs. idiopathic, were also considered. METHODS Assessment was extended to the relationships of MSNA with venous plasma norepinephrine, heart rate (HR) and echocardiographic parameters of cardiac morphology [left ventricular (LV) end-diastolic diameter] and function (LV ejection fraction) as well. RESULTS MSNA was significantly greater (1.9 times, P < 0.001) in CHF patients as compared with healthy controls, a progressive significant increase being observed from New York Heart Association classes I-IV in unadjusted and adjusted analyses. MSNA was significantly greater in both untreated and treated CHF (P < 0.001 for both), related to left ventricular (LV) end-diastolic diameter and to a lesser extent to LV ejection fraction (r = 0.24 and -0.05, P < 0.001 and <0.01, respectively), and closely associated with HR (r = 0.66, P < 0.001) and plasma norepinephrine (r = 0.68, P < 0.001). CONCLUSION CHF is characterized by sympathetic overactivity which mirrors the degree of LV dysfunction independently of the stage of CHF, its cause and presence of confounders or pharmacological treatment. plasma norepinephrine and HR represent potentially valuable surrogate markers of sympathetic activation in the clinical setting.
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22
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Collins SÉ, Phillips DB, McMurtry MS, Bryan TL, Paterson DI, Wong E, Ezekowitz JA, Forhan MA, Stickland MK. The Effect of Carotid Chemoreceptor Inhibition on Exercise Tolerance in Chronic Heart Failure. Front Physiol 2020; 11:195. [PMID: 32226392 PMCID: PMC7080702 DOI: 10.3389/fphys.2020.00195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/20/2020] [Indexed: 12/14/2022] Open
Abstract
Purpose Chronic heart failure (CHF) is characterized by heightened sympathetic nervous activity, carotid chemoreceptor (CC) sensitivity, marked exercise intolerance and an exaggerated ventilatory response to exercise. The purpose of this study was to determine the effect of CC inhibition on exercise cardiovascular and ventilatory function, and exercise tolerance in health and CHF. Methods Twelve clinically stable, optimally treated patients with CHF (mean ejection fraction: 43 ± 2.5%) and 12 age- and sex-matched healthy controls were recruited. Participants completed two time-to-symptom-limitation (TLIM) constant load cycling exercise tests at 75% peak power output with either intravenous saline or low-dose dopamine (2 μg⋅kg–1⋅min–1; order randomized). Ventilation was measured using expired gas data and operating lung volume data were determined during exercise by inspiratory capacity maneuvers. Cardiac output was estimated using impedance cardiography, and vascular conductance was calculated as cardiac output/mean arterial pressure. Results There was no change in TLIM in either group with dopamine (CHF: saline 13.1 ± 2.4 vs. dopamine 13.5 ± 1.6 min, p = 0.78; Control: saline 10.3 ± 1.2 vs. dopamine 11.5 ± 1.3 min, p = 0.16). In CHF patients, dopamine increased cardiac output (p = 0.03), vascular conductance (p = 0.01) and oxygen delivery (p = 0.04) at TLIM, while ventilatory parameters were unaffected (p = 0.76). In controls, dopamine improved vascular conductance at TLIM (p = 0.03), but no other effects were observed. Conclusion Our findings suggest that the CC contributes to cardiovascular regulation during full-body exercise in patients with CHF, however, CC inhibition does not improve exercise tolerance.
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Affiliation(s)
- Sophie É Collins
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Devin B Phillips
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - M Sean McMurtry
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Tracey L Bryan
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - D Ian Paterson
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Eric Wong
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Justin A Ezekowitz
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Mary A Forhan
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael K Stickland
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, AB, Canada
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23
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Cherneva R, Denchev S, Cherneva ZV. Autonomic dysfunction, cardio-pulmonary exercise testing and masked heart failure with preserved ejection fraction in non-severe chronic obstructive pulmonary disease. Clin Physiol Funct Imaging 2020; 40:224-231. [PMID: 32073740 DOI: 10.1111/cpf.12623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/19/2020] [Accepted: 02/06/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Autonomic dysfunction (AD) and cardiopulmonary exercise testing (CPET) parameters have been associated with masked heart failure with preserved ejection fraction (HFpEF) in the general population. Their clinical significance for masked HFpEF in chronic obstructive pulmonary disease (COPD) is however elusive. AIM The aim of the study was to determine the prevalence, correlation and clinical significance of AD and CPET with masked HFpEF, in non-severe COPD patients, complaining of exertional dyspnoea, without clinically overt cardio-vascular (CV) comorbidities. METHODS AND RESULTS We applied CPET and echocardiography in 68 COPD subjects. Echocardiography was performed before CPET and 1-2 min after peak exercise. Patients were divided into two groups: patients with and without masked HFpEF. Peak E/e' - 15 was applied as a cut-off. Chronotropic incompetence (CI) was assumed if both failure to reach the target heart rate (HR) on exercise and diminished heart rate reserve <80% occurred. Abnormal HR recovery (HRR) was taken if the decline is <12 beats within the first minute after exercise cessation. Univariate regression showed association between masked HFpEF, HRR, VO2, VO2 at AT, oxygen pulse and VE/VCO2 slope. The multivariate regression demonstrated HRR as the only independent predictor of masked HFpEF - (OR 10.28; 95% CI (3.55-29.80)). CONCLUSION Abnormal HRR is the only independent predictor of masked HFpEF in non-severe COPD patients. Despite of being associated with masked HFpEF, the lower VO2, lower oxygen pulse, higher VE/VCO2 slope and lower exercise load seem to be the consequences, rather than the triggers for it.
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Affiliation(s)
| | - Stefan Denchev
- Medical Institute of the Ministry of Interior, Sofia, Bulgaria
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24
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Machado AC, Vianna LC, Gomes EAC, Teixeira JAC, Ribeiro ML, Villacorta H, Nobrega ACL, Silva BM. Carotid chemoreflex and muscle metaboreflex interact to the regulation of ventilation in patients with heart failure with reduced ejection fraction. Physiol Rep 2020; 8:e14361. [PMID: 32026605 PMCID: PMC7002537 DOI: 10.14814/phy2.14361] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 01/16/2023] Open
Abstract
Synergism among reflexes probably contributes to exercise hyperventilation in patients with heart failure with reduced ejection fraction (HFrEF). Thus, we investigated whether the carotid chemoreflex and the muscle metaboreflex interact to the regulation of ventilation ( V ˙ E ) in HFrEF. Ten patients accomplished 4-min cycling at 60% peak workload and then recovered for 2 min under either: (a) 21% O2 inhalation (tonic carotid chemoreflex activity) with legs' circulation free (inactive muscle metaboreflex); (b) 100% O2 inhalation (suppressed carotid chemoreflex activity) with legs' circulation occluded (muscle metaboreflex activation); (c) 21% O2 inhalation (tonic carotid chemoreflex activity) with legs' circulation occluded (muscle metaboreflex activation); or (d) 100% O2 inhalation (suppressed carotid chemoreflex activity) with legs' circulation free (inactive muscle metaboreflex) as control. V ˙ E , tidal volume (VT ) and respiratory frequency (fR ) were similar between each separated reflex (protocols a and b) and control (protocol d). Calculated sum of separated reflexes effects was similar to control. Oppositely, V ˙ E (mean ± SEM: Δ vs. control = 2.46 ± 1.07 L/min, p = .05) and fR (Δ = 2.47 ± 0.77 cycles/min, p = .02) increased versus control when both reflexes were simultaneously active (protocol c). Therefore, the carotid chemoreflex and the muscle metaboreflex interacted to V ˙ E regulation in a fR -dependent manner in patients with HFrEF. If this interaction operates during exercise, it can have some contribution to the HFrEF exercise hyperventilation.
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Affiliation(s)
- Alessandro C. Machado
- Laboratory of Exercise SciencesDepartment of Physiology and PharmacologyFluminense Federal UniversityNiteróiRJBrazil
- Latin American Institute of Life and Nature SciencesFederal University of Latin American IntegrationFoz do IguaçuPRBrazil
| | - Lauro C. Vianna
- Faculty of Physical EducationUniversity of BrasíliaBrasiliaDFBrazil
| | - Erika A. C. Gomes
- Laboratory of Exercise SciencesDepartment of Physiology and PharmacologyFluminense Federal UniversityNiteróiRJBrazil
| | - Jose A. C. Teixeira
- Antonio Pedro University HospitalFaculty of MedicineFluminense Federal UniversityNiteróiRJBrazil
| | - Mario L. Ribeiro
- Antonio Pedro University HospitalFaculty of MedicineFluminense Federal UniversityNiteróiRJBrazil
| | - Humberto Villacorta
- Antonio Pedro University HospitalFaculty of MedicineFluminense Federal UniversityNiteróiRJBrazil
| | - Antonio C. L. Nobrega
- Laboratory of Exercise SciencesDepartment of Physiology and PharmacologyFluminense Federal UniversityNiteróiRJBrazil
| | - Bruno M. Silva
- Department of PhysiologyFederal University of São PauloSão PauloSPBrazil
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25
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Roder F, Wellmann B, Bitter T, Fox H, Türoff A, Spiesshoefer J, Tamisier R, Horstkotte D, Oldenburg O. Sleep duration and architecture during ASV for central sleep apnoea in systolic heart failure. Respir Physiol Neurobiol 2020; 271:103286. [DOI: 10.1016/j.resp.2019.103286] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 01/19/2023]
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26
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Faini A, Caravita S, Parati G, Castiglioni P. Alterations of Cardiovascular Complexity during Acute Exposure to High Altitude: A Multiscale Entropy Approach. ENTROPY 2019. [PMCID: PMC7514569 DOI: 10.3390/e21121224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Stays at high altitude induce alterations in cardiovascular control and are a model of specific pathological cardiovascular derangements at sea level. However, high-altitude alterations of the complex cardiovascular dynamics remain an almost unexplored issue. Therefore, our aim is to describe the altered cardiovascular complexity at high altitude with a multiscale entropy (MSE) approach. We recorded the beat-by-beat series of systolic and diastolic blood pressure and heart rate in 20 participants for 15 min twice, at sea level and after arrival at 4554 m a.s.l. We estimated Sample Entropy and MSE at scales of up to 64 beats, deriving average MSE values over the scales corresponding to the high-frequency (MSEHF) and low-frequency (MSELF) bands of heart-rate variability. We found a significant loss of complexity at heart-rate and blood-pressure scales complementary to each other, with the decrease with high altitude being concentrated at Sample Entropy and at MSEHF for heart rate and at MSELF for blood pressure. These changes can be ascribed to the acutely increased chemoreflex sensitivity in hypoxia that causes sympathetic activation and hyperventilation. Considering high altitude as a model of pathological states like heart failure, our results suggest new ways for monitoring treatments and rehabilitation protocols.
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Affiliation(s)
- Andrea Faini
- Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, S.Luca Hospital, 20149 Milan, Italy; (A.F.); (S.C.)
| | - Sergio Caravita
- Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, S.Luca Hospital, 20149 Milan, Italy; (A.F.); (S.C.)
- Department of Management, Information and Production Engineering, University of Bergamo, 24044 Dalmine, Italy
| | - Gianfranco Parati
- Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, S.Luca Hospital, 20149 Milan, Italy; (A.F.); (S.C.)
- Department of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- Correspondence:
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27
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Toledo C, Andrade DC, Díaz HS, Pereyra KV, Schwarz KG, Díaz-Jara E, Oliveira LM, Takakura AC, Moreira TS, Schultz HD, Marcus NJ, Del Rio R. Rostral ventrolateral medullary catecholaminergic neurones mediate irregular breathing pattern in volume overload heart failure rats. J Physiol 2019; 597:5799-5820. [PMID: 31642520 DOI: 10.1113/jp278845] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/14/2019] [Indexed: 08/25/2023] Open
Abstract
KEY POINTS A strong association between disordered breathing patterns, elevated sympathetic activity, and enhanced central chemoreflex drive has been shown in experimental and human heart failure (HF). The aim of this study was to determine the contribution of catecholaminergic rostral ventrolateral medulla catecholaminergic neurones (RVLM-C1) to both haemodynamic and respiratory alterations in HF. Apnoea/hypopnoea incidence (AHI), breathing variability, respiratory-cardiovascular coupling, cardiac autonomic control and cardiac function were analysed in HF rats with or without selective ablation of RVLM-C1 neurones. Partial lesion (∼65%) of RVLM-C1 neurones reduces AHI, respiratory variability, and respiratory-cardiovascular coupling in HF rats. In addition, the deleterious effects of central chemoreflex activation on cardiac autonomic balance and cardiac function in HF rats was abolished by ablation of RVLM-C1 neurones. Our findings suggest that RVLM-C1 neurones play a pivotal role in breathing irregularities in volume overload HF, and mediate the sympathetic responses induced by acute central chemoreflex activation. ABSTRACT Rostral ventrolateral medulla catecholaminergic neurones (RVLM-C1) modulate sympathetic outflow and breathing under normal conditions. Heart failure (HF) is characterized by chronic RVLM-C1 activation, increased sympathetic activity and irregular breathing patterns. Despite studies showing a relationship between RVLM-C1 and sympathetic activity in HF, no studies have addressed a potential contribution of RVLM-C1 neurones to irregular breathing in this context. Thus, the aim of this study was to determine the contribution of RVLM-C1 neurones to irregular breathing patterns in HF. Sprague-Dawley rats underwent surgery to induce volume overload HF. Anti-dopamine β-hydroxylase-saporin toxin (DβH-SAP) was used to selectively lesion RVLM-C1 neurones. At 8 weeks post-HF induction, breathing pattern, blood pressures (BP), respiratory-cardiovascular coupling (RCC), central chemoreflex function, cardiac autonomic control and cardiac function were studied. Reduction (∼65%) of RVLM-C1 neurones resulted in attenuation of irregular breathing, decreased apnoea-hypopnoea incidence (11.1 ± 2.9 vs. 6.5 ± 2.5 events h-1 ; HF+Veh vs. HF+DβH-SAP; P < 0.05) and improved cardiac autonomic control in HF rats. Pathological RCC was observed in HF rats (peak coherence >0.5 between breathing and cardiovascular signals) and was attenuated by DβH-SAP treatment (coherence: 0.74 ± 0.12 vs. 0.54 ± 0.10, HF+Veh vs. HF+DβH-SAP rats; P < 0.05). Central chemoreflex activation had deleterious effects on cardiac function and cardiac autonomic control in HF rats that were abolished by lesion of RVLM-C1 neurones. Our findings reveal that RVLM-C1 neurones play a major role in irregular breathing patterns observed in volume overload HF and highlight their contribution to cardiac dysautonomia and deterioration of cardiac function during chemoreflex activation.
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Affiliation(s)
- Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación en Fisiología del Ejercicio, Universidad Mayor, Santiago, Chile
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Katherin V Pereyra
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Karla G Schwarz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Esteban Díaz-Jara
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luiz M Oliveira
- Department of Pharmacology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA, USA
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
- Centro de Envejecimiento y Regeneración (CARE-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
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28
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Díaz HS, Andrade DC, Toledo C, Pereyra KV, Schwarz KG, Díaz-Jara E, Lucero C, Arce-Álvarez A, Schultz HD, Silva JN, Takakura AC, Moreira TS, Marcus NJ, Del Rio R. Episodic stimulation of central chemoreceptor neurons elicits disordered breathing and autonomic dysfunction in volume overload heart failure. Am J Physiol Lung Cell Mol Physiol 2019; 318:L27-L40. [PMID: 31617729 PMCID: PMC6985876 DOI: 10.1152/ajplung.00007.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Enhanced central chemoreflex (CC) gain is observed in volume overload heart failure (HF) and is correlated with autonomic dysfunction and breathing disorders. The aim of this study was to determine the role of the CC in the development of respiratory and autonomic dysfunction in HF. Volume overload was surgically created to induce HF in male Sprague-Dawley rats. Radiotelemetry transmitters were implanted for continuous monitoring of blood pressure and heart rate. After recovering from surgery, conscious unrestrained rats were exposed to episodic hypercapnic stimulation [EHS; 10 cycles/5 min, inspiratory fraction of carbon dioxide (FICO2) 7%] in a whole body plethysmograph for recording of cardiorespiratory function. To determine the contribution of CC to cardiorespiratory variables, selective ablation of chemoreceptor neurons within the retrotrapezoid nucleus (RTN) was performed via injection of saporin toxin conjugated to substance P (SSP-SAP). Vehicle-treated rats (HF+Veh and Sham+Veh) were used as controls for SSP-SAP experiments. Sixty minutes post-EHS, minute ventilation was depressed in sham animals relative to HF animals (ΔV̇e: -5.55 ± 2.10 vs. 1.24 ± 1.35 mL/min 100 g, P < 0.05; Sham+Veh vs. HF+Veh). Furthermore, EHS resulted in autonomic imbalance, cardiorespiratory entrainment, and ventilatory disturbances in HF+Veh but not Sham+Veh rats, and these effects were significantly attenuated by SSP-SAP treatment. Also, the apnea-hypopnea index (AHI) was significantly lower in HF+SSP-SAP rats compared with HF+Veh rats (AHI: 5.5 ± 0.8 vs. 14.4 ± 1.3 events/h, HF+SSP-SAP vs. HF+Veh, respectively, P < 0.05). Finally, EHS-induced respiratory-cardiovascular coupling in HF rats depends on RTN chemoreceptor neurons because it was reduced by SSP-SAP treatment. Overall, EHS triggers ventilatory plasticity and elicits cardiorespiratory abnormalities in HF that are largely dependent on RTN chemoreceptor neurons.
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Affiliation(s)
- Hugo S Díaz
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - David C Andrade
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Investigación en Fisiología del Ejercicio (CIFE), Universidad Mayor, Santiago, Chile
| | - Camilo Toledo
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Envejecimiento y Regeneración (CARE-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Katherin V Pereyra
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Karla G Schwarz
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Esteban Díaz-Jara
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia Lucero
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis Arce-Álvarez
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Centre, Omaha, Nebraska
| | - Josiane N Silva
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, Iowa
| | - Rodrigo Del Rio
- Laboratory Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Envejecimiento y Regeneración (CARE-UC), Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Excelencia de Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
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29
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Giannoni A, Raglianti V, Taddei C, Borrelli C, Chubuchny V, Vergaro G, Mirizzi G, Valleggi A, Cameli M, Pasanisi E, Emdin M, Passino C. Cheyne-Stokes respiration related oscillations in cardiopulmonary hemodynamics in patients with heart failure. Int J Cardiol 2019; 289:76-82. [DOI: 10.1016/j.ijcard.2019.03.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 03/15/2019] [Indexed: 12/26/2022]
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30
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Moore LE, Kapoor K, Byers BW, Brotto AR, Ghods-Esfahani D, Henry SL, St James RB, Stickland MK. Acute effects of salbutamol on systemic vascular function in people with asthma. Respir Med 2019; 155:133-140. [PMID: 31349187 DOI: 10.1016/j.rmed.2019.07.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Asthmatics are at increased cardiovascular disease risk, which has been linked to beta2(β2)-agonist use. Inhalation of β2-agonists increases sympathetic nerve activity (SNA) in healthy individuals, however the systemic impact of salbutamol in asthmatics using β2-agonists regularly is unknown. OBJECTIVES This study compared the systemic vascular responses to a clinical dose of salbutamol (Phase I) and following an acute increase in SNA (Phase II) in asthmatics and controls. METHODS Fourteen controls and 14 asthmatics were recruited for Phase I. On separate days, flow-mediated dilation (FMD) and peripheral arterial stiffness (pPWV) were evaluated at baseline and following either 400 μg inhaled salbutamol or a placebo inhaler. For Phase II, heart rate, blood pressure, vascular conductance, pPWV, and central (c)PWV were evaluated in response to a large increase in SNA brought on by cold-water hand immersion (i.e. cold-pressor test) or body-temperature water hand immersion (i.e. control) in 10 controls and 10 asthmatics. RESULTS Following salbutamol, asthmatics demonstrated reduced FMD (-3.0%, p < 0.05) and increased pPWV (+0.7 m/s, p < 0.05); however, salbutamol had no effect in controls. The cold-pressor test resulted in similar increases in blood pressure, vascular flow rates and conductance, pPWV, and cPWV in both asthmatics and controls, suggesting similar neurovascular transduction in asthmatics and controls. CONCLUSION Inhaled Salbutamol leads to increased arterial stiffness and reduced FMD in asthmatics. As asthmatics and controls had similar vascular responses to an increase in SNA, these findings suggest asthmatics have heightened sympathetic responses to β2-agonists which may contribute to the increased cardiovascular risk in asthma.
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Affiliation(s)
- Linn E Moore
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Karishma Kapoor
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Department of Psychology, Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Bradley W Byers
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Andrew R Brotto
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Daniel Ghods-Esfahani
- Department of Biological Sciences, Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Shelby L Henry
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Department of Rehabilitation Science, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Ryan B St James
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Michael K Stickland
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada.
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31
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Guyenet PG, Stornetta RL, Holloway BB, Souza GMPR, Abbott SBG. Rostral Ventrolateral Medulla and Hypertension. Hypertension 2019; 72:559-566. [PMID: 30354763 DOI: 10.1161/hypertensionaha.118.10921] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Patrice G Guyenet
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Ruth L Stornetta
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Benjamin B Holloway
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - George M P R Souza
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Stephen B G Abbott
- From the Department of Pharmacology, University of Virginia, Charlottesville
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32
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Mansur AP, Alvarenga GS, Kopel L, Gutierrez MA, Consolim-Colombo FM, Abrahão LH, Lage SG. Cerebral blood flow changes during intermittent acute hypoxia in patients with heart failure. J Int Med Res 2018; 46:4214-4225. [PMID: 30130981 PMCID: PMC6166355 DOI: 10.1177/0300060518791691] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective Heart failure (HF) is associated with intermittent hypoxia, and the effects of this hypoxia on the cardiovascular system are not well understood. This study was performed to compare the effects of acute hypoxia (10% oxygen) between patients with and without HF. Methods Fourteen patients with chronic HF and 17 matched control subjects were enrolled. Carotid artery changes were examined during the first period of hypoxia, and brachial artery changes were examined during the second period of hypoxia. Data were collected at baseline and after 2 and 4 minutes of hypoxia. Norepinephrine, epinephrine, dopamine, and renin were measured at baseline and after 4 minutes hypoxia. Results The carotid blood flow, carotid systolic diameter, and carotid diastolic diameter increased and the carotid resistance decreased in patients with HF. Hypoxia did not change the carotid compliance, distensibility, brachial artery blood flow and diameter, or concentrations of sympathomimetic amines in patients with HF, but hypoxia increased the norepinephrine level in the control group. Hypoxia increased minute ventilation and decreased the oxygen saturation and end-tidal carbon dioxide concentration in both groups. Conclusion Hypoxia-induced changes in the carotid artery suggest an intensification of compensatory mechanisms for preservation of cerebral blood flow in patients with HF.
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Affiliation(s)
- Antonio P Mansur
- Heart Institute (InCor) - Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Glaura Souza Alvarenga
- Heart Institute (InCor) - Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Liliane Kopel
- Heart Institute (InCor) - Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Marco Antonio Gutierrez
- Heart Institute (InCor) - Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | | | - Ludhmila Hajjar Abrahão
- Heart Institute (InCor) - Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Silvia Gelas Lage
- Heart Institute (InCor) - Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
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33
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Liao WH, Suendermann C, Steuer AE, Pacheco Lopez G, Odermatt A, Faresse N, Henneberg M, Langhans W. Aldosterone deficiency in mice burdens respiration and accentuates diet-induced hyperinsulinemia and obesity. JCI Insight 2018; 3:99015. [PMID: 30046010 DOI: 10.1172/jci.insight.99015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022] Open
Abstract
Aldosterone synthase inhibitors (ASIs) should alleviate obesity-related cardiovascular and renal problems resulting partly from aldosterone excess, but their clinical use may have limitations. To improve knowledge for the use of ASIs, we investigated physiology in aldosterone synthase-knockout (ASKO) mice. On regular chow diet (CD), ASKO mice ate more and weighed less than WT mice, largely because they hyperventilated to eliminate acid as CO2. Replacing CD with high-fat diet (HFD) lessened the respiratory burden in ASKO mice, as did 12- to 15-hour fasting. The latter eliminated the genotype differences in respiratory workload and energy expenditure (EE). Thus, aldosterone deficiency burdened the organism more when the animals ate carbohydrate-rich chow than when they ate a HFD. Chronic HFD exposure further promoted hyperinsulinemia in ASKO mice that contributed to visceral fat accumulation accompanied by reduced lipolysis, thermogenic reprogramming, and the absence of weight-gain-related EE increases. Intracerebroventricular aldosterone supplementation in ASKO mice attenuated the HFD-induced hyperinsulinemia, but did not affect EE, suggesting that the presence of aldosterone increased the body's energetic efficiency, thus counteracting the EE-increasing effect of low insulin. ASIs may therefore cause acid-overload-induced respiratory burden and promote obesity. Their use in patients with preexisting renal and cardiopulmonary diseases might be contraindicated.
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Affiliation(s)
- Wan-Hui Liao
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.,Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Center of Competence in Research "Kidney.CH", Switzerland
| | | | - Andrea Eva Steuer
- Department of Forensic Pharmacology and Toxicology, Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Gustavo Pacheco Lopez
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.,Department of Health Sciences, Division of Biological and Health Sciences, Metropolitan Autonomous University (UAM), Lerma, Mexico
| | - Alex Odermatt
- National Center of Competence in Research "Kidney.CH", Switzerland.,Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Nourdine Faresse
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Center of Competence in Research "Kidney.CH", Switzerland
| | - Maciej Henneberg
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.,Biological Anthropology and Comparative Anatomy Unit, University of Adelaide, Australia
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
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34
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Weatherald J, Sattler C, Garcia G, Laveneziana P. Ventilatory response to exercise in cardiopulmonary disease: the role of chemosensitivity and dead space. Eur Respir J 2018; 51:51/2/1700860. [PMID: 29437936 DOI: 10.1183/13993003.00860-2017] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 11/11/2017] [Indexed: 12/30/2022]
Abstract
The lungs and heart are irrevocably linked in their oxygen (O2) and carbon dioxide (CO2) transport functions. Functional impairment of the lungs often affects heart function and vice versa The steepness with which ventilation (V'E) rises with respect to CO2 production (V'CO2 ) (i.e. the V'E/V'CO2 slope) is a measure of ventilatory efficiency and can be used to identify an abnormal ventilatory response to exercise. The V'E/V'CO2 slope is a prognostic marker in several chronic cardiopulmonary diseases independent of other exercise-related variables such as peak O2 uptake (V'O2 ). The V'E/V'CO2 slope is determined by two factors: 1) the arterial CO2 partial pressure (PaCO2 ) during exercise and 2) the fraction of the tidal volume (VT) that goes to dead space (VD) (i.e. the physiological dead space ratio (VD/VT)). An altered PaCO2 set-point and chemosensitivity are present in many cardiopulmonary diseases, which influence V'E/V'CO2 by affecting PaCO2 Increased ventilation-perfusion heterogeneity, causing inefficient gas exchange, also contributes to the abnormal V'E/V'CO2 observed in cardiopulmonary diseases by increasing VD/VT During cardiopulmonary exercise testing, the PaCO2 during exercise is often not measured and VD/VT is only estimated by taking into account the end-tidal CO2 partial pressure (PETCO2 ); however, PaCO2 is not accurately estimated from PETCO2 in patients with cardiopulmonary disease. Measuring arterial gases (PaO2 and PaCO2 ) before and during exercise provides information on the real (and not "estimated") VD/VT coupled with a true measure of gas exchange efficiency such as the difference between alveolar and arterial O2 partial pressure and the difference between arterial and end-tidal CO2 partial pressure during exercise.
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Affiliation(s)
- Jason Weatherald
- Dept of Medicine, Division of Respiratory Medicine, University of Calgary, Calgary, AB, Canada.,Université Paris-Sud and Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Service de Pneumologie, AP-HP, Hôpital Bicêtre, Le Kremlin-Bicêtre, France.,Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Caroline Sattler
- Université Paris-Sud and Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Service de Pneumologie, AP-HP, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Gilles Garcia
- Université Paris-Sud and Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Service de Pneumologie, AP-HP, Hôpital Bicêtre, Le Kremlin-Bicêtre, France.,These authors contributed equally to this work and are both last authors
| | - Pierantonio Laveneziana
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMRS_1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France .,Service des Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée, Dépt "R3S", Pôle PRAGUES, AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Paris, France.,These authors contributed equally to this work and are both last authors
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35
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Guyenet PG, Bayliss DA, Stornetta RL, Kanbar R, Shi Y, Holloway BB, Souza GMPR, Basting TM, Abbott SBG, Wenker IC. Interdependent feedback regulation of breathing by the carotid bodies and the retrotrapezoid nucleus. J Physiol 2017; 596:3029-3042. [PMID: 29168167 DOI: 10.1113/jp274357] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022] Open
Abstract
The retrotrapezoid nucleus (RTN) regulates breathing in a CO2 - and state-dependent manner. RTN neurons are glutamatergic and innervate principally the respiratory pattern generator; they regulate multiple aspects of breathing, including active expiration, and maintain breathing automaticity during non-REM sleep. RTN neurons encode arterial PCO2 /pH via cell-autonomous and paracrine mechanisms, and via input from other CO2 -responsive neurons. In short, RTN neurons are a pivotal structure for breathing automaticity and arterial PCO2 homeostasis. The carotid bodies stimulate the respiratory pattern generator directly and indirectly by activating RTN via a neuronal projection originating within the solitary tract nucleus. The indirect pathway operates under normo- or hypercapnic conditions; under respiratory alkalosis (e.g. hypoxia) RTN neurons are silent and the excitatory input from the carotid bodies is suppressed. Also, silencing RTN neurons optogenetically quickly triggers a compensatory increase in carotid body activity. Thus, in conscious mammals, breathing is subject to a dual and interdependent feedback regulation by chemoreceptors. Depending on the circumstance, the activity of the carotid bodies and that of RTN vary in the same or the opposite directions, producing additive or countervailing effects on breathing. These interactions are mediated either via changes in blood gases or by brainstem neuronal connections, but their ultimate effect is invariably to minimize arterial PCO2 fluctuations. We discuss the potential relevance of this dual chemoreceptor feedback to cardiorespiratory abnormalities present in diseases in which the carotid bodies are hyperactive at rest, e.g. essential hypertension, obstructive sleep apnoea and heart failure.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Benjamin B Holloway
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Tyler M Basting
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University, New Orleans, Louisiana 70112, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ian C Wenker
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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36
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Andrade DC, Arce-Alvarez A, Toledo C, Díaz HS, Lucero C, Quintanilla RA, Schultz HD, Marcus NJ, Amann M, Del Rio R. Revisiting the physiological effects of exercise training on autonomic regulation and chemoreflex control in heart failure: does ejection fraction matter? Am J Physiol Heart Circ Physiol 2017; 314:H464-H474. [PMID: 29167119 DOI: 10.1152/ajpheart.00407.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heart failure (HF) is a global public health problem that, independent of its etiology [reduced (HFrEF) or preserved ejection fraction (HFpEF)], is characterized by functional impairments of cardiac function, chemoreflex hypersensitivity, baroreflex sensitivity (BRS) impairment, and abnormal autonomic regulation, all of which contribute to increased morbidity and mortality. Exercise training (ExT) has been identified as a nonpharmacological therapy capable of restoring normal autonomic function and improving survival in patients with HFrEF. Improvements in autonomic function after ExT are correlated with restoration of normal peripheral chemoreflex sensitivity and BRS in HFrEF. To date, few studies have addressed the effects of ExT on chemoreflex control, BRS, and cardiac autonomic control in HFpEF; however, there are some studies that have suggested that ExT has a beneficial effect on cardiac autonomic control. The beneficial effects of ExT on cardiac function and autonomic control in HF may have important implications for functional capacity in addition to their obvious importance to survival. Recent studies have suggested that the peripheral chemoreflex may also play an important role in attenuating exercise intolerance in HFrEF patients. The role of the central/peripheral chemoreflex, if any, in mediating exercise intolerance in HFpEF has not been investigated. The present review focuses on recent studies that address primary pathophysiological mechanisms of HF (HFrEF and HFpEF) and the potential avenues by which ExT exerts its beneficial effects.
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Affiliation(s)
- David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación en Fisiología del Ejercicio, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Alexis Arce-Alvarez
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | - Claudia Lucero
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Investigación Biomédica, Universidad Autónoma de Chile , Santiago , Chile
| | | | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center , Omaha, Nebraska
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University , Des Moines, Iowa
| | - Markus Amann
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile , Santiago , Chile.,Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes , Punta Arenas , Chile.,Centro de Envejecimiento y Regeneracion, Pontificia Universidad Católica de Chile, Santiago, Chile
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37
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Fisher JP, Flück D, Hilty MP, Lundby C. Carotid chemoreceptor control of muscle sympathetic nerve activity in hypobaric hypoxia. Exp Physiol 2017; 103:77-89. [DOI: 10.1113/ep086493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/12/2017] [Indexed: 12/16/2022]
Affiliation(s)
- James P. Fisher
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences; University of Birmingham; Edgbaston Birmingham UK
| | - Daniela Flück
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences; University of British Columbia - Okanagan; Kelowna British Columbia Canada
- Zurich Center for Integrative Human Physiology (ZIHP), Institute of Physiology; University of Zurich; Switzerland
| | - Matthias P. Hilty
- Intensive Care Unit; University Hospital of Zürich; Zürich Switzerland
| | - Carsten Lundby
- Zurich Center for Integrative Human Physiology (ZIHP), Institute of Physiology; University of Zurich; Switzerland
- Center for Physical Activity Research (CFAS); University Hospital of Copenhagen; Copenhagen Denmark
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38
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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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39
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Affiliation(s)
- Marat Fudim
- Division of Cardiology, Department of Internal Medicine, Duke University Hospital, Durham, NC
| | - Adrian F Hernandez
- Division of Cardiology, Department of Internal Medicine, Duke University Hospital, Durham, NC
- Duke Cardiovascular Research Institute, Durham, NC
| | - G Michael Felker
- Division of Cardiology, Department of Internal Medicine, Duke University Hospital, Durham, NC
- Duke Cardiovascular Research Institute, Durham, NC
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40
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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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Pfoh JR, Steinback CD, Vanden Berg ER, Bruce CD, Day TA. Assessing chemoreflexes and oxygenation in the context of acute hypoxia: Implications for field studies. Respir Physiol Neurobiol 2017; 246:67-75. [PMID: 28757365 DOI: 10.1016/j.resp.2017.07.006] [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: 03/09/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 11/30/2022]
Abstract
Carotid chemoreceptors detect changes in PO2 and elicit a peripheral respiratory chemoreflex (PCR). The PCR can be tested through a transient hypoxic ventilatory response test (TT-HVR), which may not be safe nor feasible at altitude. We characterized a transient hyperoxic ventilatory withdrawal test in the setting of steady-state normobaric hypoxia (13.5-14% FIO2) and compared it to a TT-HVR and a steady-state poikilocapnic hypoxia test, within-individuals. No PCR test magnitude was correlated with any other test, nor was any test magnitude correlated with oxygenation while in steady-state hypoxia. Due to the heterogeneity between the different PCR test procedures and magnitudes, and the confounding effects of alterations in CO2 acting on both central and peripheral chemoreceptors, we developed a novel method to assess prevailing steady-state chemoreflex drive in the context of hypoxia. Quantifying peak hypoxic/hyperoxic responses at low altitude may have minimal utility in predicting oxygenation during ascent to altitude, and here we advance a novel index of chemoreflex drive.
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Affiliation(s)
- Jamie R Pfoh
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada; Department of Biology, Faculty of Science, University of Victoria, Canada
| | - Craig D Steinback
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Canada; Department of Biology, Faculty of Science, University of Victoria, Canada
| | - Emily R Vanden Berg
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada; Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Canada; Department of Biology, Faculty of Science, University of Victoria, Canada
| | - Christina D Bruce
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada; Department of Biology, Faculty of Science, University of Victoria, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada; Department of Biology, Faculty of Science, University of Victoria, Canada.
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Bianchi L, Porta C, Rinaldi A, Gazzaruso C, Fratino P, DeCata P, Protti P, Paltro R, Bernardi L. Integrated cardiovascular/respiratory control in type 1 diabetes evidences functional imbalance: Possible role of hypoxia. Int J Cardiol 2017; 244:254-259. [PMID: 28666602 DOI: 10.1016/j.ijcard.2017.06.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/09/2017] [Accepted: 06/12/2017] [Indexed: 11/18/2022]
Abstract
BACKGROUND Cardiovascular (baroreflex) and respiratory (chemoreflex) control mechanisms were studied separately in diabetes, but their reciprocal interaction (well known for diseases like heart failure) had never been comprehensively assessed. We hypothesized that prevalent autonomic neuropathy would depress both reflexes, whereas prevalent autonomic imbalance through sympathetic activation would depress the baroreflex but enhance the chemoreflexes. METHODS In 46 type-1 diabetic subjects (7.0±0.9year duration) and 103 age-matched controls we measured the baroreflex (average of 7 methods), and the chemoreflexes, (hypercapnic: ventilation/carbon dioxide slope during hyperoxic progressive hypercapnia; hypoxic: ventilation/oxygen saturation slope during normocapnic progressive hypoxia). Autonomic dysfunction was evaluated by cardiovascular reflex tests. RESULTS Resting oxygen saturation and baroreflex sensitivity were reduced in the diabetic group, whereas the hypercapnic chemoreflex was significantly increased in the entire diabetic group. Despite lower oxygen saturation the hypoxic chemoreflex showed a trend toward a depression in the diabetic group. CONCLUSION Cardio-respiratory control imbalance is a common finding in early type 1 diabetes. A reduced sensitivity to hypoxia seems a primary factor leading to reflex sympathetic activation (enhanced hypercapnic chemoreflex and baroreflex depression), hence suggesting a functional origin of cardio-respiratory control imbalance in initial diabetes.
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Affiliation(s)
- L Bianchi
- Department of Internal Medicine, University of Pavia, Pavia, Italy
| | - C Porta
- Department of Internal Medicine, University of Pavia, Pavia, Italy
| | - A Rinaldi
- Department of Internal Medicine, University of Pavia, Pavia, Italy
| | - C Gazzaruso
- Department of Internal Medicine and Endocrinology, IRCCS Fondazione S.Maugeri, Pavia, Italy
| | - P Fratino
- Department of Internal Medicine and Endocrinology, IRCCS Fondazione S.Maugeri, Pavia, Italy
| | - P DeCata
- Department of Internal Medicine and Endocrinology, IRCCS Fondazione S.Maugeri, Pavia, Italy
| | - P Protti
- Department of Internal Medicine, University of Pavia, Pavia, Italy
| | - R Paltro
- Department of Internal Medicine, University of Pavia, Pavia, Italy
| | - L Bernardi
- Department of Internal Medicine, University of Pavia, Pavia, Italy; Folkhälsan Institute of Genetics, Folkhälsan Research Center, University of Helsinki, Helsinki, Finland.
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Mezzani A, Giordano A, Komici K, Corrà U. Different Determinants of Ventilatory Inefficiency at Different Stages of Reduced Ejection Fraction Chronic Heart Failure Natural History. J Am Heart Assoc 2017; 6:JAHA.116.005278. [PMID: 28487387 PMCID: PMC5524084 DOI: 10.1161/jaha.116.005278] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background It is not known whether determinants of ventilation (VE)/volume of exhaled carbon dioxide (VCO2) slope during incremental exercise may differ at different stages of reduced ejection fraction chronic heart failure natural history. Methods and Results VE/VCO2 slope was fitted up to lowest VE/VCO2 ratio, that is, a proxy of the VE/perfusion ratio devoid of nonmetabolic stimuli to ventilatory drive. VE/VCO2 slope tertiles were generated from our database (<27.5 [tertile 1], ≥27.5 to <32.0 [tertile 2], and ≥32.0 [tertile 3]), and 147 chronic heart failure patients with repeated tests yielding VE/VCO2 slopes in 2 different tertiles were selected. Determinants of VE/VCO2 slope changes across tertile pairs 1 versus 2, 2 versus 3, and 1 versus 3 were assessed by exploring changes in VE and VCO2 at lowest VE/VCO2 and those in VE/work rate (W) and VCO2/W slope. Resting and peak cardiac output (CO) were calculated as VO2/estimated arteriovenous O2 difference and the CO/W slope analyzed. Notwithstanding a progressively lower W with increasing tertile, VE at lowest VE/VCO2 and VE/W slope were significantly higher in tertiles 2 and 3 versus tertile 1. Conversely, VCO2 at lowest VE/VCO2 and CO/W slope significantly decreased across tertiles, whereas VCO2/W slope did not. Difference (Δ) in VE/W slope between tertiles accounted for 71% of ΔVE/VCO2 slope variance, with ΔVCO2/W slope explaining an additional 26% (model r=0.99; r2=0.97; P<0.0001). Similar results were obtained substituting ΔVCO2/W slope with ΔCO/W slope. Conclusions Ventilatory overactivation is the predominant cause of VE/VCO2 slope increase at initial stages of chronic heart failure, whereas hemodynamic impairment plays an additional role at more‐advanced pathophysiological stages.
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Affiliation(s)
- Alessandro Mezzani
- Exercise Pathophysiology Laboratory, Cardiac Rehabilitation Division, Istituti Clinici Scientifici Maugeri Spa SB-Scientific Institute of Veruno IRCCS, Veruno (NO), Italy
| | - Andrea Giordano
- Bioengineering Service, Istituti Clinici Scientifici Maugeri Spa SB-Scientific Institute of Veruno IRCCS, Veruno (NO), Italy
| | - Klara Komici
- Exercise Pathophysiology Laboratory, Cardiac Rehabilitation Division, Istituti Clinici Scientifici Maugeri Spa SB-Scientific Institute of Veruno IRCCS, Veruno (NO), Italy
| | - Ugo Corrà
- Exercise Pathophysiology Laboratory, Cardiac Rehabilitation Division, Istituti Clinici Scientifici Maugeri Spa SB-Scientific Institute of Veruno IRCCS, Veruno (NO), Italy
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Toledo C, Andrade DC, Lucero C, Arce-Alvarez A, Díaz HS, Aliaga V, Schultz HD, Marcus NJ, Manríquez M, Faúndez M, Del Rio R. Cardiac diastolic and autonomic dysfunction are aggravated by central chemoreflex activation in heart failure with preserved ejection fraction rats. J Physiol 2017; 595:2479-2495. [PMID: 28181258 DOI: 10.1113/jp273558] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/31/2017] [Indexed: 12/30/2022] Open
Abstract
KEY POINTS Heart failure with preserved ejection fraction (HFpEF) is associated with disordered breathing patterns, and sympatho-vagal imbalance. Although it is well accepted that altered peripheral chemoreflex control plays a role in the progression of heart failure with reduced ejection fraction (HFrEF), the pathophysiological mechanisms underlying deterioration of cardiac function in HFpEF are poorly understood. We found that central chemoreflex is enhanced in HFpEF and neuronal activation is increased in pre-sympathetic regions of the brainstem. Our data showed that activation of the central chemoreflex pathway in HFpEF exacerbates diastolic dysfunction, worsens sympatho-vagal imbalance and markedly increases the incidence of cardiac arrhythmias in rats with HFpEF. ABSTRACT Heart failure (HF) patients with preserved ejection fraction (HFpEF) display irregular breathing, sympatho-vagal imbalance, arrhythmias and diastolic dysfunction. It has been shown that tonic activation of the central and peripheral chemoreflex pathway plays a pivotal role in the pathophysiology of HF with reduced ejection fraction. In contrast, no studies to date have addressed chemoreflex function or its effect on cardiac function in HFpEF. Therefore, we tested whether peripheral and central chemoreflexes are hyperactive in HFpEF and if chemoreflex activation exacerbates cardiac dysfunction and autonomic imbalance. Sprague-Dawley rats (n = 32) were subjected to sham or volume overload to induce HFpEF. Resting breathing variability, chemoreflex gain, cardiac function and sympatho-vagal balance, and arrhythmia incidence were studied. HFpEF rats displayed [mean ± SD; chronic heart failure (CHF) vs. Sham, respectively] a marked increase in the incidence of apnoeas/hypopnoeas (20.2 ± 4.0 vs. 9.7 ± 2.6 events h-1 ), autonomic imbalance [0.6 ± 0.2 vs. 0.2 ± 0.1 low/high frequency heart rate variability (LF/HFHRV )] and cardiac arrhythmias (196.0 ± 239.9 vs. 19.8 ± 21.7 events h-1 ). Furthermore, HFpEF rats showed increase central chemoreflex sensitivity but not peripheral chemosensitivity. Accordingly, hypercapnic stimulation in HFpEF rats exacerbated increases in sympathetic outflow to the heart (229.6 ± 43.2% vs. 296.0 ± 43.9% LF/HFHRV , normoxia vs. hypercapnia, respectively), incidence of cardiac arrhythmias (196.0 ± 239.9 vs. 576.7 ± 472.9 events h-1 ) and diastolic dysfunction (0.008 ± 0.004 vs. 0.027 ± 0.027 mmHg μl-1 ). Importantly, the cardiovascular consequences of central chemoreflex activation were related to sympathoexcitation since these effects were abolished by propranolol. The present results show that the central chemoreflex is enhanced in HFpEF and that acute activation of central chemoreceptors leads to increases of cardiac sympathetic outflow, cardiac arrhythmogenesis and impairment in cardiac function in rats with HFpEF.
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Affiliation(s)
- Camilo Toledo
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Claudia Lucero
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Alexis Arce-Alvarez
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Valentín Aliaga
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Centre, Omaha, NE, USA
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA, USA
| | - Mónica Manríquez
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Marcelo Faúndez
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Universidad Autónoma de Chile, Santiago, Chile
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Positive airway pressure therapy in heart failure patients: Long-term effects on lung function. Respir Physiol Neurobiol 2017; 238:41-46. [PMID: 28126479 DOI: 10.1016/j.resp.2017.01.010] [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] [Received: 09/09/2016] [Revised: 01/17/2017] [Accepted: 01/21/2017] [Indexed: 11/21/2022]
Abstract
PURPOSE The prevalence of sleep-disordered breathing (SDB) in patients with heart failure (HF) is high. Positive airway pressure (PAP) is first-choice therapy, but recent data indicates that PAP therapy may increase mortality in HF patients with reduced ejection fraction (HF-REF) and predominant central sleep apnea (CSA). This study investigated long-term effects of PAP therapy on pulmonary function, including respiratory muscle strength. All patients underwent multichannel cardiorespiratory polysomnography (PSG) and comprehensive lung function testing at baseline and follow-up (mean 588±43days). RESULTS 350 patients (mean age 68±10.7years, 88% male) were included, inspiratory vital capacity, 3.3±0.9 vs 3.2±0.8L; forced expiratory volume in 1s, 2.5±0.7 vs 2.4±0.7L; lung diffusion capacity, 6.2±1.9 vs 5.9±1.8mmol/min/kPa; correction for hemoglobin, 1.1±0.02 vs 1.1±0.3mmol/min/kPa/L; and mouth occlusion pressure, 0.42±0.11 vs 0.4±0.12kPa. CONCLUSIONS PAP therapy had no negative nor positive impact on lung function, including respiratory muscle strength, in stable HF-REF patients with SDB, and is therefore safe from a respiratory perspective.
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46
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Recruitment Maneuver in Elderly Patients with Different Peripheral Chemoreflex Sensitivity during Major Abdominal Surgery. BIOMED RESEARCH INTERNATIONAL 2017; 2016:2974852. [PMID: 28070507 PMCID: PMC5187456 DOI: 10.1155/2016/2974852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/22/2016] [Indexed: 12/01/2022]
Abstract
The goal of the study was to evaluate the effect of a recruitment maneuver on respiratory biomechanics, oxygenation, and hemodynamics in patients suffering from chronic heart failure with different peripheral chemoreflex sensitivity. The study was conducted in 115 elderly patients which underwent major abdominal surgery under general/epidural surgery. Peripheral chemoreflex sensitivity (PCS) was evaluated with breath-holding duration (BHD) during breath-holding test. All patients were divided into two groups: group H had a high PCS (BHD = 38 seconds or less, n = 49); Group M had a middle PCS (BHD more than 38 seconds, n = 66). Recruitment maneuver improved oxygenation and respiratory biomechanics in all cases. However, cardiac output decreased by an average of 18%–31% in group H compared to 18%–28% in group M. SVR either remained unchanged or decreased by up to 14% of the initial value in group H, while, in group M, it had a tendency to increase, which was 24% of the initial value. So, recruitment maneuver is an effective method to improve oxygenation and biomechanical properties of the respiratory system but in patients with increased peripheral chemoreflex sensitivity it associates with the risk of hemodynamic disturbances.
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Paleczny B, Olesińska M, Siennicka A, Niewiński P, Jankowska EA, Ponikowska B, Banasiak W, Von Haehling S, Anker SD, Ponikowski P. Central Chemoreceptor Sensitivity Is Not Enhanced in Contemporary Patients With Chronic Systolic Heart Failure Receiving Optimal Treatment. J Card Fail 2016; 23:83-87. [PMID: 27867115 DOI: 10.1016/j.cardfail.2016.11.003] [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] [Received: 05/09/2016] [Revised: 11/07/2016] [Accepted: 11/15/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Clinical and prognostic consequences of enhanced central chemosensitivity in the contemporary optimally treated patients with chronic heart failure (CHF) are unknown. METHODS AND RESULTS We studied central chemosensitivity (defined as hypercapnic ventilatory response [HCVR; L/min/mmHg]) in 161 CHF patients (mean left ventricular ejection fraction [LVEF] 31 ± 6%, all receiving a combination of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and beta-blocker) and 55 sex- and age-matched healthy controls. HCVR did not differ between CHF patients and controls (median 0.63 vs 0.57 L/min-1/mmHg-1, P = .76). When the CHF patients were divided into tertiles according to their HCVR values, there were no significant differences in clinical characteristics (except for ischemic etiology, which was more frequent in those with the highest HCVR), results of the cardiopulmonary exercise testing, and indices of heart rate variability. During the follow-up (median 28 months, range 1-48 months, ≥15 months in all survivors), 21 patients died. HCVR was not related to survival in the Cox proportional hazards analysis. CONCLUSIONS Central chemosensitivity is not enhanced in contemporary, optimally treated CHF patients and its assessment does not provide significant clinical or prognostic information.
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Affiliation(s)
- Bartłomiej Paleczny
- Department of Physiology, Wroclaw Medical University, Wroclaw, Poland; Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.
| | - Martyna Olesińska
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Agnieszka Siennicka
- Department of Physiology, Wroclaw Medical University, Wroclaw, Poland; Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Piotr Niewiński
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Ewa A Jankowska
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland; Laboratory for Applied Research on Cardiovascular System, Department of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
| | - Beata Ponikowska
- Department of Physiology, Wroclaw Medical University, Wroclaw, Poland
| | - Waldemar Banasiak
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Stephan Von Haehling
- Division of Innovative Clinical Trials, Department of Cardiology & Pulmonology, University Medicine Göttingen (UMG), Göttingen, Germany
| | - Stefan D Anker
- Division of Innovative Clinical Trials, Department of Cardiology & Pulmonology, University Medicine Göttingen (UMG), Göttingen, Germany
| | - Piotr Ponikowski
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland; Department of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
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Trembach N, Zabolotskikh I. Breath-holding test in evaluation of peripheral chemoreflex sensitivity in healthy subjects. Respir Physiol Neurobiol 2016; 235:79-82. [PMID: 27756650 DOI: 10.1016/j.resp.2016.10.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/04/2016] [Accepted: 10/09/2016] [Indexed: 11/19/2022]
Abstract
The aim of the study was to determine the feasibility of using a breath-holding test in assessing the sensitivity of the peripheral chemoreflex compared with the single-breath carbon dioxide test. The study involved 48 healthy volunteers between the ages of 18-29 years. The breath-holding test was performed followed by the single-breath carbon dioxide test on the next day. A month after the first tests, these tests were repeated to evaluate their reproducibility The coefficient of variability in the single-breath carbon dioxide test ranged from 0 to 32% with a mean of 10±7%. The mean coefficient of variability of the breath-holding test was 6±4% (0-19%). A significant inverse correlation between the results of the two tests was noted following analysis (r=-0.82, p<0.05). CONCLUSION A breath-holding test after deep inspiration reflects the sensitivity of the peripheral chemoreflex as defined by the single-breath carbon dioxide test in healthy subjects.
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Affiliation(s)
- Nikita Trembach
- Kuban State Medical University, 350012, Krasnodar, Sedin str., 4, Russian Federation.
| | - Igor Zabolotskikh
- Kuban State Medical University, 350012, Krasnodar, Sedin str., 4, Russian Federation
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Sympathetic neural and cardiovascular responses during static handgrip exercise in women with a history of hypertensive pregnancy. Clin Auton Res 2016; 26:395-405. [PMID: 27506589 DOI: 10.1007/s10286-016-0372-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/26/2016] [Indexed: 02/07/2023]
Abstract
PURPOSE Women with a history of hypertensive pregnancy are at greater risk for future cardiovascular events; however, the mechanisms for this increased risk are unknown. Evidence suggests that an exercise stimulus unmasks latent hypertensive tendencies, identifying individuals at the greatest risk for developing cardiovascular disease. The current study examined the hypothesis that women with a hypertensive pregnancy history exhibit an augmented exercise pressor response. METHODS Normotensive women with a history of healthy pregnancy (CON; n = 9) and hypertensive pregnancy (HP+; n = 12) were studied during the mid-luteal phase of the menstrual cycle. Heart rate (HR), systolic and diastolic blood pressure (SBP, DBP), and muscle sympathetic nerve activity (MSNA) were measured during a cold pressor test (CPT), and, following a sufficient period of recovery, during static handgrip to fatigue (SHG) and post-exercise circulatory arrest (PECA). RESULTS The BP, HR, and MSNA responses to the CPT were similar between groups. The SBP response to SHG and PECA was similar between groups, but DBP and HR were significantly greater in HP+ women (both p < 0.05). MSNA burst frequency, but not burst incidence or total activity, tended to be elevated in HP+ women during the stressor (peak Δ from baseline 31 ± 13 vs. 23 ± 13 bursts/min; p for group = 0.06). CONCLUSION Despite no clinical signs of cardiovascular disease or hypertension, women with a history of hypertensive pregnancy display an enhanced cardiovascular reactivity to an exercise stimulus compared to women with a healthy pregnancy history. This response may be indicative of impaired cardiovascular control that precedes the clinical manifestation of hypertension or cardiovascular events.
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Does the Sympathetic Nervous System Adapt to Chronic Altitude Exposure? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:375-93. [DOI: 10.1007/978-1-4899-7678-9_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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