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Olea E, Valverde-Pérez E, Docio I, Prieto-Lloret J, Aaronson PI, Rocher A. Pulmonary Vascular Responses to Chronic Intermittent Hypoxia in a Guinea Pig Model of Obstructive Sleep Apnea. Int J Mol Sci 2024; 25:7484. [PMID: 39000591 PMCID: PMC11242077 DOI: 10.3390/ijms25137484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 07/02/2024] [Accepted: 07/05/2024] [Indexed: 07/16/2024] Open
Abstract
Experimental evidence suggests that chronic intermittent hypoxia (CIH), a major hallmark of obstructive sleep apnea (OSA), boosts carotid body (CB) responsiveness, thereby causing increased sympathetic activity, arterial and pulmonary hypertension, and cardiovascular disease. An enhanced circulatory chemoreflex, oxidative stress, and NO signaling appear to play important roles in these responses to CIH in rodents. Since the guinea pig has a hypofunctional CB (i.e., it is a natural CB knockout), in this study we used it as a model to investigate the CB dependence of the effects of CIH on pulmonary vascular responses, including those mediated by NO, by comparing them with those previously described in the rat. We have analyzed pulmonary artery pressure (PAP), the hypoxic pulmonary vasoconstriction (HPV) response, endothelial function both in vivo and in vitro, and vascular remodeling (intima-media thickness, collagen fiber content, and vessel lumen area). We demonstrate that 30 days of the exposure of guinea pigs to CIH (FiO2, 5% for 40 s, 30 cycles/h) induces pulmonary artery remodeling but does not alter endothelial function or the contractile response to phenylephrine (PE) in these arteries. In contrast, CIH exposure increased the systemic arterial pressure and enhanced the contractile response to PE while decreasing endothelium-dependent vasorelaxation to carbachol in the aorta without causing its remodeling. We conclude that since all of these effects are independent of CB sensitization, there must be other oxygen sensors, beyond the CB, with the capacity to alter the autonomic control of the heart and vascular function and structure in CIH.
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Affiliation(s)
- Elena Olea
- Departamento de Enfermería, Facultad de Enfermería Universidad de Valladolid, 47005 Valladolid, Spain
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, 47005 Valladolid, Spain
| | - Esther Valverde-Pérez
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, 47005 Valladolid, Spain
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Inmaculada Docio
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Jesus Prieto-Lloret
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, 47005 Valladolid, Spain
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Philip I Aaronson
- Department of Inflammation Biology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London SE1 9RT, UK
| | - Asunción Rocher
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, 47005 Valladolid, Spain
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, 47005 Valladolid, Spain
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Mao Z, Zheng P, Zhu X, Wang L, Zhang F, Liu H, Li H, Zhou L, Liu W. Obstructive sleep apnea hypopnea syndrome and vascular lesions: An update on what we currently know. Sleep Med 2024; 119:296-311. [PMID: 38723575 DOI: 10.1016/j.sleep.2024.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/23/2024] [Accepted: 05/02/2024] [Indexed: 06/18/2024]
Abstract
Obstructive sleep apnea-hypopnea syndrome (OSAHS) is the most prevalent sleep and respiratory disorder. This syndrome can induce severe cardiovascular and cerebrovascular complications, and intermittent hypoxia is a pivotal contributor to this damage. Vascular pathology is closely associated with the impairment of target organs, marking a focal point in current research. Vascular lesions are the fundamental pathophysiological basis of multiorgan ailments and indicate a shared pathogenic mechanism among common cardiovascular and cerebrovascular conditions, suggesting their importance as a public health concern. Increasing evidence shows a strong correlation between OSAHS and vascular lesions. Previous studies predominantly focused on the pathophysiological alterations in OSAHS itself, such as intermittent hypoxia and fragmented sleep, leading to vascular disruptions. This review aims to delve deeper into the vascular lesions affected by OSAHS by examining the microscopic pathophysiological mechanisms involved. Emphasis has been placed on examining how OSAHS induces vascular lesions through disruptions in the endothelial barrier, metabolic dysregulation, cellular phenotype alterations, neuroendocrine irregularities, programmed cell death, vascular inflammation, oxidative stress and epigenetic modifications. This review examines the epidemiology and associated risk factors for OSAHS and vascular diseases and subsequently describes the existing evidence on vascular lesions induced by OSAHS in the cardiovascular, cerebrovascular, retinal, renal and reproductive systems. A detailed account of the current research on the pathophysiological mechanisms mediating vascular lesions caused by OSAHS is provided, culminating in a discussion of research advancements in therapeutic modalities to mitigate OSAHS-related vascular lesions and the implications of these treatment strategies.
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Affiliation(s)
- Zhenyu Mao
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pengdou Zheng
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyan Zhu
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lingling Wang
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fengqin Zhang
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiguo Liu
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hai Li
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, China
| | - Ling Zhou
- Department of Respiratory and Critical Care Medicine, National Health Committee (NHC) Key Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Wei Liu
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, China.
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Shafer BM, West CR, Foster GE. Advancements in the neurocirculatory reflex response to hypoxia. Am J Physiol Regul Integr Comp Physiol 2024; 327:R1-R13. [PMID: 38738293 PMCID: PMC11380992 DOI: 10.1152/ajpregu.00237.2023] [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: 10/23/2023] [Revised: 04/16/2024] [Accepted: 04/29/2024] [Indexed: 05/14/2024]
Abstract
Hypoxia is a pivotal factor in the pathophysiology of various clinical conditions, including obstructive sleep apnea, which has a strong association with cardiovascular diseases like hypertension, posing significant health risks. Although the precise mechanisms linking hypoxemia-associated clinical conditions with hypertension remains incompletely understood, compelling evidence suggests that hypoxia induces plasticity of the neurocirculatory control system. Despite variations in experimental designs and the severity, frequency, and duration of hypoxia exposure, evidence from animal and human models consistently demonstrates the robust effects of hypoxemia in triggering reflex-mediated sympathetic activation. Both acute and chronic hypoxia alters neurocirculatory regulation and, in some circumstances, leads to sympathetic outflow and elevated blood pressures that persist beyond the hypoxic stimulus. Dysregulation of autonomic control could lead to adverse cardiovascular outcomes and increase the risk of developing hypertension.
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Affiliation(s)
- Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Christopher R West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, British Columbia, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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Panza GS, Burtscher J, Zhao F. Intermittent hypoxia: a call for harmonization in terminology. J Appl Physiol (1985) 2023; 135:886-890. [PMID: 37560767 PMCID: PMC10642510 DOI: 10.1152/japplphysiol.00458.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 08/11/2023] Open
Abstract
Mild intermittent hypoxia may be a potent novel strategy to improve cardiovascular function, motor and cognitive function, and altitude acclimatization. However, there is still a stigma surrounding the field of intermittent hypoxia (IH). Major contributors to this stigma may be due to the overlapping terminology, heterogeneous methodological approaches, and an almost dogmatic focus on different mechanistic underpinnings in different fields of research. Many clinicians and investigators explore the pathophysiological outcomes following long-term exposure to IH in an attempt to improve our understanding of sleep apnea (SA) and develop new treatment plans. However, others use IH as a tool to improve physiological outcomes such as blood pressure, motor function, and altitude acclimatization. Unfortunately, studies investigating the pathophysiology of SA or the potential benefit of IH use similar, unstandardized terminologies facilitating a confusion surrounding IH protocols and the intentions of various studies. In this perspective paper, we aim to highlight IH terminology-related issues with the aim of spurring harmonization of the terminology used in the field of IH research to account for distinct outcomes of hypoxia exposure depending on protocol and individuum.
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Affiliation(s)
- Gino S Panza
- Department of Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan, United States
- Department of Health Care Sciences, Program of Occupational Therapy, Wayne State University, Detroit, Michigan, United States
| | - Johannes Burtscher
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Fei Zhao
- Department of Research and Development, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan, United States
- Department of Health Care Sciences, Program of Occupational Therapy, Wayne State University, Detroit, Michigan, United States
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Mechanism Underlying Triple VEGFR Inhibitor Tivozanib-Induced Hypertension in Mice Model. Pharmaceuticals (Basel) 2023. [DOI: 10.3390/ph16020295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Tivozanib is a triple vascular endothelial growth factor receptor inhibitor, recently approved for the treatment of refractory advanced renal cell carcinoma. Clinical studies showed that around 46% of patients who received tivozanib suffer from hypertension in all grades. Thus, the present study was conducted to identify the role of angiotensin-II (AngII) in the mechanism underlying tivozanib-induced vascular toxicity and hypertension. C57BL/6 male mice received tivozanib (1 mg/kg) with or without losartan (10 or 30 mg/kg) for 3 weeks. Blood pressure was recorded every 3 days, and proteinuria was measured every week. On day 21, all mice were euthanized, and samples were harvested for further analysis. Tivozanib elevated blood pressure until systolic blood pressure reached 163 ± 6.6 mmHg on day 21 of treatment with low urination and high proteinuria. AngII and its receptors, endothelin-1, and oxidative stress markers were significantly increased. While nitric oxide (NO) levels were reduced in plasma and aortic tissues. AngII type 1 receptor blockade by losartan prevented these consequences caused by tivozanib and kept blood pressure within normal range. The results showed that AngII and ET-1 might be potential targets in the clinical studies and management of hypertension induced by tivozanib.
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Fan J, Chen D, Wang N, Su R, Li H, Ma H, Gao F. Negative relationship between brain-derived neurotrophic factor (BDNF) and attention: A possible elevation in BDNF level among high-altitude migrants. Front Neurol 2023; 14:1144959. [PMID: 37114226 PMCID: PMC10126458 DOI: 10.3389/fneur.2023.1144959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/27/2023] [Indexed: 04/29/2023] Open
Abstract
Objective Brain-derived neurotrophic factor (BDNF), a member of the neurotrophic family that plays a vital role in regulating neuronal activity and synaptic plasticity in the brain, affects attention. However, studies investigating the association between BDNF and attention in long-term high-altitude (HA) migrants are limited in the literature. As HA affects both BDNF and attention, the relationship between these factors becomes more complex. Therefore, this study aimed to evaluate the relationship between peripheral blood concentrations of BDNF and the three attentional networks in both behavioral and electrical aspects of the brain in long-term HA migrants. Materials and methods Ninety-eight Han adults (mean age: 34.74 ± 3.48 years, 51 females and 47 males, all have lived at Lhasa for 11.30 ± 3.82 years) were recruited in this study. For all participants, the serum BDNF levels were assessed using enzyme-linked immunosorbent assay; event-related potentials (N1, P1, and P3) were recorded during the Attentional Networks Test, which was used as the measure of three attentional networks. Results Executive control scores were negatively correlated with P3 amplitude (r = -0.20, p = 0.044), and serum BDNF levels were positively correlated with executive control scores (r = 0.24, p = 0.019) and negatively correlated with P3 amplitude (r = -0.22, p = 0.027). Through grouping of BDNF levels and three attentional networks, executive control was found to be significantly higher in the high BDNF group than in the low BDNF group (p = 0.010). Different BDNF levels were associated with both orienting scores (χ2 = 6.99, p = 0.030) and executive control scores (χ2 = 9.03, p = 0.011). The higher the BDNF level, the worse was the executive function and the lower was the average P3 amplitude and vice versa. Females were found to have higher alerting scores than males (p = 0.023). Conclusion This study presented the relationship between BDNF and attention under HA. The higher the BDNF level, the worse was the executive control, suggesting that after long-term exposure to HA, hypoxia injury of the brain may occur in individuals with relatively higher BDNF levels, and this higher BDNF level may be the result of self-rehabilitation tackling the adverse effects brought by the HA environment.
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Affiliation(s)
- Jing Fan
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
| | - Dongmei Chen
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
- Office of Safety and Health, Lhasa No. 1 Middle School, Lhasa, China
| | - Niannian Wang
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
| | - Rui Su
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
- Beijing Key Laboratory of Behavior and Mental Health, School of Psychological and Cognitive Sciences, Peking University, Beijing, China
| | - Hao Li
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
| | - Hailin Ma
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
- Academy of Plateau Science and Sustainability, People's Government of Qinghai Province, Xining, China
- *Correspondence: Hailin Ma
| | - Fei Gao
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
- Fei Gao
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Farré R, Almendros I, Martínez-García MÁ, Gozal D. Experimental Models to Study End-Organ Morbidity in Sleep Apnea: Lessons Learned and Future Directions. Int J Mol Sci 2022; 23:ijms232214430. [PMID: 36430904 PMCID: PMC9696027 DOI: 10.3390/ijms232214430] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/22/2022] Open
Abstract
Sleep apnea (SA) is a very prevalent sleep breathing disorder mainly characterized by intermittent hypoxemia and sleep fragmentation, with ensuing systemic inflammation, oxidative stress, and immune deregulation. These perturbations promote the risk of end-organ morbidity, such that SA patients are at increased risk of cardiovascular, neurocognitive, metabolic and malignant disorders. Investigating the potential mechanisms underlying SA-induced end-organ dysfunction requires the use of comprehensive experimental models at the cell, animal and human levels. This review is primarily focused on the experimental models employed to date in the study of the consequences of SA and tackles 3 different approaches. First, cell culture systems whereby controlled patterns of intermittent hypoxia cycling fast enough to mimic the rates of episodic hypoxemia experienced by patients with SA. Second, animal models consisting of implementing realistic upper airway obstruction patterns, intermittent hypoxia, or sleep fragmentation such as to reproduce the noxious events characterizing SA. Finally, human SA models, which consist either in subjecting healthy volunteers to intermittent hypoxia or sleep fragmentation, or alternatively applying oxygen supplementation or temporary nasal pressure therapy withdrawal to SA patients. The advantages, limitations, and potential improvements of these models along with some of their pertinent findings are reviewed.
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Affiliation(s)
- Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain
- CIBER de Enfermedades Respiratorias, 1964603 Madrid, Spain
- Institut Investigacions Biomediques August Pi Sunyer, 08036 Barcelona, Spain
- Correspondence: (R.F.); (D.G.)
| | - Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain
- CIBER de Enfermedades Respiratorias, 1964603 Madrid, Spain
- Institut Investigacions Biomediques August Pi Sunyer, 08036 Barcelona, Spain
| | - Miguel-Ángel Martínez-García
- CIBER de Enfermedades Respiratorias, 1964603 Madrid, Spain
- Pneumology Department, University and Polytechnic La Fe Hospital, 46026 Valencia, Spain
| | - David Gozal
- Department of Child Health and Child Health Research Institute, School of Medicine, The University of Missouri, Columbia, MO 65201, USA
- Correspondence: (R.F.); (D.G.)
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Panza GS, Puri S, Lin HS, Badr MS, Mateika JH. Daily Exposure to Mild Intermittent Hypoxia Reduces Blood Pressure in Male Patients with Obstructive Sleep Apnea and Hypertension. Am J Respir Crit Care Med 2022; 205:949-958. [PMID: 35015980 PMCID: PMC9838631 DOI: 10.1164/rccm.202108-1808oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Rationale: Daily exposure to mild intermittent hypoxia (MIH) may elicit beneficial cardiovascular outcomes. Objectives: To determine the effect of 15 days of MIH and in-home continuous positive airway pressure treatment on blood pressure in participants with obstructive sleep apnea and hypertension. Methods: We administered MIH during wakefulness 5 days/week for 3 weeks. The protocol consisted of twelve 2-minute bouts of hypoxia interspersed with 2 minutes of normoxia. End-tidal carbon dioxide was maintained 2 mm Hg above baseline values throughout the protocol. Control participants were exposed to a sham protocol (i.e., compressed air). All participants were treated with continuous positive airway pressure over the 3-week period. Results are mean ± SD. Measurements and Main Results: Sixteen male participants completed the study (experimental n = 10; control n = 6). Systolic blood pressure at rest during wakefulness over 24 hours was reduced after 15 days of MIH (142.9 ± 8.6 vs. 132.0 ± 10.7 mm Hg; P < 0.001), but not following the sham protocol (149.9 ± 8.6 vs. 149.7 ± 10.8 mm Hg; P = 0.915). Thus, the reduction in blood pressure from baseline was greater in the experimental group compared with control (-10.91 ± 4.1 vs. -0.17 ± 3.6 mm Hg; P = 0.003). Modifications in blood pressure were accompanied by increased parasympathetic and reduced sympathetic activity in the experimental group, as estimated by blood pressure and heart rate variability analysis. No detrimental neurocognitive and metabolic outcomes were evident following MIH. Conclusions: MIH elicits beneficial cardiovascular and autonomic outcomes in males with OSA and concurrent hypertension. Clinical trial registered with www.clinicaltrials.gov (NCT03736382).
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Affiliation(s)
- Gino S. Panza
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and,Department of Physiology
| | - Shipra Puri
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and,Department of Physiology
| | - Ho-Sheng Lin
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and,Department of Otolaryngology, and
| | - M. Safwan Badr
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and,Department of Physiology,,Department of Internal Medicine, School of Medicine, Wayne State University, Detroit, Michigan
| | - Jason H. Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and,Department of Physiology,,Department of Internal Medicine, School of Medicine, Wayne State University, Detroit, Michigan
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Gavrilin MA, Porter K, Samouilov A, Khayat RN. Pathways of Microcirculatory Endothelial Dysfunction in Obstructive Sleep Apnea: A Comprehensive Ex Vivo Evaluation in Human Tissue. Am J Hypertens 2022; 35:347-355. [PMID: 34694354 PMCID: PMC8976176 DOI: 10.1093/ajh/hpab169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The mechanism and markers of cardiovascular disease (CVD) in obstructive sleep apnea (OSA) remain unknown. The microcirculation is the site of early changes in OSA patients who are free of CVD risk. METHODS Patients with newly diagnosed moderate to severe OSA (n = 7) were studied before and 12 weeks after intensive treatment with continuous positive airway pressure (CPAP), along with weight and age matched controls (n = 7). Microcirculatory vessels were isolated from gluteal biopsies and changes in critical functional genes were measured. RESULTS The following genes changed after 12 weeks of intensive CPAP therapy in the microcirculatory vessels: angiotensin receptor type 1 (AGTR-1) (11.6 (3.4) to 6 (0.8); P = 0.019); NADPH oxidase (NOX4) (0.85 (0.02) to 0.79 (0.11); P = 0.016); and dimethylarginine dimethylaminohydrolase (DDAH 1) (1 (0.31) to 0.55 (0.1); P = 0.028). Despite decreased nitric oxide (NO) availability as measured indirectly through brachial artery flow-mediated dilation, endothelial NO synthase (NOS3) did not change with CPAP. Other disease markers of OSA that changed with treatment in the microcirculation were endothelin, hypoxia inducible factor 1a, nuclear factor kappa B, interleukin-8, and interleukin-6. CONCLUSIONS In this ex vivo evaluation of the microcirculation of patients with OSA and no CVD risk, several pathways of CVD were activated supporting that OSA independently induces microcirculatory endothelial dysfunction and serving as disease-specific markers for future pharmacological targeting of OSA-related CVD risk. The findings support the role of renin-angiotensin activation and endothelial oxidative stress in the decreased microcirculatory NO availability in OSA.
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Affiliation(s)
| | - Kyle Porter
- The Center for Biostatistics, The Ohio State University, Columbus, Ohio, USA
| | - Alexandre Samouilov
- Department of Medicine, The Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Rami N Khayat
- The Sleep Heart Program, The Ohio State University, Columbus, Ohio, USA
- The Division of Pulmonary and Critical Medicine and the UCI Sleep Disorders Center, Departments of Medicine and Psychiatry, the University of California-Irvine, Irvine, California, USA
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10
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Beaudin AE, Hanly PJ, Raneri JK, Younes M, Pun M, Anderson TJ, Poulin MJ. Impact of intermittent hypoxia on human vascular responses during sleep. Exp Neurol 2021; 347:113897. [PMID: 34655575 DOI: 10.1016/j.expneurol.2021.113897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 10/05/2021] [Accepted: 10/10/2021] [Indexed: 11/27/2022]
Abstract
Exposure to intermittent hypoxia (IH) ≥15 times per hour is believed to be the primary mechanism for the increased risk of cerebrovascular and cardiovascular disease in patients with moderate to severe sleep apnea. Human experimental models of IH used to investigate this link have been predominantly employed during wakefulness, which limits extrapolation of findings to sleep apnea where IH occurs during sleep. Moreover, how IH impacts vascular regulation during sleep has not been measured quantitatively. Therefore, the objective of this study was to assess the impact sleep accompanied by IH on vascular responses to hypoxia and hypercapnia during sleep. Ten males performed two randomly scheduled 6-h overnight sleep studies. One sleep study was performed in room air (normoxia) and the other sleep study was performed during isocapnic IH (60 s hypoxia-60 s normoxia). On each night, cerebrovascular (peak blood velocity through the middle cerebral artery (V¯P); transcranial Doppler ultrasound) and cardiovascular (blood pressure, heart rate) responses to hypoxia and hypercapnia were measured before sleep onset (PM-Awake), within the first 2 h of sleep (PM-Asleep), in the 5th (out of 6) hours of sleep (AM-Asleep) and after being awoken in the morning (AM-Awake). Sleep accompanied by IH had no impact on the V¯P and blood pressure responses to hypoxia and hypercapnic at any timepoint (p ≥ 0.103 for all responses). However, the AM-Awake heart rate response to hypoxia was greater following sleep in IH compared to sleep in normoxia. Independent of the sleep environment, the V¯P response to hypoxia and hypercapnia were reduced during sleep. In conclusion, cerebral blood flow responses are reduced during sleep compared to wakefulness, but 6 h of sleep accompanied by IH does not alter cerebrovascular and cardiovascular response to hypoxia and hypercapnia during wakefulness or sleep in healthy young humans. However, it is likely that longer exposure to IH during sleep (i.e., days-to-weeks) is required to better elucidate IH's impact on vascular regulation in humans.
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Affiliation(s)
- Andrew E Beaudin
- University of Calgary, Cumming School of Medicine, Department of Physiology and Pharmacology, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; Hotchkiss Brain Institute, University of Calgary, Cumming School of Medicine, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada
| | - Patrick J Hanly
- Hotchkiss Brain Institute, University of Calgary, Cumming School of Medicine, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; University of Calgary, Cumming School of Medicine, Department of Medicine, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; Sleep Centre, Foothills Medical Centre, 1403 29 St NW, Calgary, Alberta T2N 2T9, Canada
| | - Jill K Raneri
- Sleep Centre, Foothills Medical Centre, 1403 29 St NW, Calgary, Alberta T2N 2T9, Canada
| | - Magdy Younes
- University of Manitoba, Department of Medicine, 1105-255 Wellington Crescent, Winnipeg, Manitoba R3M 3V4, Canada
| | - Matiram Pun
- University of Calgary, Cumming School of Medicine, Department of Physiology and Pharmacology, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; Hotchkiss Brain Institute, University of Calgary, Cumming School of Medicine, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada
| | - Todd J Anderson
- University of Calgary, Cumming School of Medicine, Department of Cardiac Science, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Marc J Poulin
- University of Calgary, Cumming School of Medicine, Department of Physiology and Pharmacology, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; Hotchkiss Brain Institute, University of Calgary, Cumming School of Medicine, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada; Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
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11
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Puri S, Panza G, Mateika JH. A comprehensive review of respiratory, autonomic and cardiovascular responses to intermittent hypoxia in humans. Exp Neurol 2021; 341:113709. [PMID: 33781731 PMCID: PMC8527806 DOI: 10.1016/j.expneurol.2021.113709] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/17/2021] [Accepted: 03/24/2021] [Indexed: 01/08/2023]
Abstract
This review explores forms of respiratory and autonomic plasticity, and associated outcome measures, that are initiated by exposure to intermittent hypoxia. The review focuses primarily on studies that have been completed in humans and primarily explores the impact of mild intermittent hypoxia on outcome measures. Studies that have explored two forms of respiratory plasticity, progressive augmentation of the hypoxic ventilatory response and long-term facilitation of ventilation and upper airway muscle activity, are initially reviewed. The role these forms of plasticity might have in sleep disordered breathing are also explored. Thereafter, the role of intermittent hypoxia in the initiation of autonomic plasticity is reviewed and the role this form of plasticity has in cardiovascular and hemodynamic responses during and following intermittent hypoxia is addressed. The role of these responses in individuals with sleep disordered breathing and spinal cord injury are subsequently addressed. Ultimately an integrated picture of the respiratory, autonomic and cardiovascular responses to intermittent hypoxia is presented. The goal of the integrated picture is to address the types of responses that one might expect in humans exposed to one-time and repeated daily exposure to mild intermittent hypoxia. This form of intermittent hypoxia is highlighted because of its potential therapeutic impact in promoting functional improvement and recovery in several physiological systems.
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Affiliation(s)
- Shipra Puri
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States of America; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States of America
| | - Gino Panza
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States of America; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States of America
| | - Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States of America; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States of America; Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201, United States of America.
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12
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Acute intermittent hypercapnic hypoxia and cerebral neurovascular coupling in males and females. Exp Neurol 2020; 334:113441. [DOI: 10.1016/j.expneurol.2020.113441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/10/2020] [Accepted: 08/21/2020] [Indexed: 01/01/2023]
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13
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Brown CV, Boulet LM, Vermeulen TD, Sands SA, Wilson RJA, Ayas NT, Floras JS, Foster GE. Angiotensin II-Type I Receptor Antagonism Does Not Influence the Chemoreceptor Reflex or Hypoxia-Induced Central Sleep Apnea in Men. Front Neurosci 2020; 14:382. [PMID: 32410951 PMCID: PMC7198907 DOI: 10.3389/fnins.2020.00382] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/27/2020] [Indexed: 12/15/2022] Open
Abstract
Components of the renin-angiotensin system (RAS) situated within the carotid body or central nervous system may promote hypoxia-induced chemoreceptor reflex sensitization or central sleep apnea (CSA). We determined if losartan, an angiotensin-II type-I receptor (AT1R) antagonist, would attenuate chemoreceptor reflex sensitivity before or after 8 h of nocturnal hypoxia, and consequently CSA severity. In a double-blind, randomized, placebo-controlled, crossover protocol, 14 men (age: 25 ± 2 years; BMI: 24.6 ± 1.1 kg/m2; means ± SEM) ingested 3 doses of either losartan (50 mg) or placebo every 8 h. Chemoreceptor reflex sensitivity was assessed during hypoxic and hyperoxic hypercapnic ventilatory response (HCVR) tests and during six-20s hypoxic apneas before and after 8 h of sleep in normobaric hypoxia (FIO2 = 0.135). Loop gain was assessed from a ventilatory control model fitted to the ventilatory pattern of CSA recorded during polysomnography. Prior to nocturnal hypoxia, losartan had no effect on either the hyperoxic (losartan: 3.6 ± 1.1, placebo: 4.0 ± 0.6 l/min/mmHg; P = 0.9) or hypoxic HCVR (losartan: 5.3 ± 1.4, placebo: 5.7 ± 0.68 l/min/mmHg; P = 1.0). Likewise, losartan did not influence either the hyperoxic (losartan: 4.2 ± 1.3, placebo: 3.8 ± 1.1 l/min/mmHg; P = 0.5) or hypoxic HCVR (losartan: 6.6 ± 1.8, placebo: 6.3 ± 1.5 l/min/mmHg; P = 0.9) after nocturnal hypoxia. Cardiorespiratory responses to apnea and participants’ apnea hypopnea indexes during placebo and losartan were similar (73 ± 15 vs. 75 ± 14 events/h; P = 0.9). Loop gain, which correlated with CSA severity (r = 0.94, P < 0.001), was similar between treatments. In summary, in young healthy men, hypoxia-induced CSA severity is strongly associated with loop gain, but the AT1R does not modulate chemoreceptor reflex sensitivity before or after 8 h of nocturnal hypoxia.
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Affiliation(s)
- Courtney V Brown
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - Tyler D Vermeulen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Richard J A Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Najib T Ayas
- Sleep Disorders Program, University of British Columbia, Vancouver, BC, Canada.,Respiratory and Critical Care Divisions, University of British Columbia, Vancouver, BC, Canada
| | - John S Floras
- University Health Network and Sinai Health System Division of Cardiology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
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14
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Ayas NT, Foster GE, Shah N, Floras J, Laher I. Could Adjunctive Pharmacology Mitigate Cardiovascular Consequences of Obstructive Sleep Apnea? Am J Respir Crit Care Med 2020; 200:551-555. [PMID: 30875238 DOI: 10.1164/rccm.201811-2097pp] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Najib T Ayas
- Sleep Disorders Program.,Division of Respiratory Medicine and.,Division of Critical Care Medicine, Department of Medicine, and.,Canadian Sleep and Circadian Network and
| | - Glen E Foster
- Canadian Sleep and Circadian Network and.,Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | - Neomi Shah
- Division of Pulmonary, Critical Care, and Sleep, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - John Floras
- Division of Cardiology, Department of Medicine, University Health Network and Sinai Health System, University of Toronto, Toronto, Ontario, Canada
| | - Ismail Laher
- Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Canadian Sleep and Circadian Network and
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15
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Stuckless TJR, Vermeulen TD, Brown CV, Boulet LM, Shafer BM, Wakeham DJ, Steinback CD, Ayas NT, Floras JS, Foster GE. Acute intermittent hypercapnic hypoxia and sympathetic neurovascular transduction in men. J Physiol 2020; 598:473-487. [PMID: 31805605 DOI: 10.1113/jp278941] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/03/2019] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS Intermittent hypoxia leads to long-lasting increases in muscle sympathetic nerve activity and blood pressure, contributing to increased risk for hypertension in obstructive sleep apnoea patients. We determined whether augmented vascular responses to increasing sympathetic vasomotor outflow, termed sympathetic neurovascular transduction (sNVT), accompanied changes in blood pressure following acute intermittent hypercapnic hypoxia in men. Lower body negative pressure was utilized to induce a range of sympathetic vasoconstrictor firing while measuring beat-by-beat blood pressure and forearm vascular conductance. IH reduced vascular shear stress and steepened the relationship between diastolic blood pressure and sympathetic discharge frequency, suggesting greater systemic sNVT. Our results indicate that recurring cycles of acute intermittent hypercapnic hypoxia characteristic of obstructive sleep apnoea could promote hypertension by increasing sNVT. ABSTRACT Acute intermittent hypercapnic hypoxia (IH) induces long-lasting elevations in sympathetic vasomotor outflow and blood pressure in healthy humans. It is unknown whether IH alters sympathetic neurovascular transduction (sNVT), measured as the relationship between sympathetic vasomotor outflow and either forearm vascular conductance (FVC; regional sNVT) or diastolic blood pressure (systemic sNVT). We tested the hypothesis that IH augments sNVT by exposing healthy males to 40 consecutive 1 min breathing cycles, each comprising 40 s of hypercapnic hypoxia ( P ETC O 2 : +4 ± 3 mmHg above baseline; P ET O 2 : 48 ± 3 mmHg) and 20 s of normoxia (n = 9), or a 40 min air-breathing control (n = 7). Before and after the intervention, lower body negative pressure (LBNP; 3 min at -15, -30 and -45 mmHg) was applied to elicit reflex increases in muscle sympathetic nerve activity (MSNA, fibular microneurography) when clamping end-tidal gases at baseline levels. Ventilation, arterial pressure [systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP)], brachial artery blood flow ( Q ̇ BA ), FVC ( Q ̇ BA /MAP) and MSNA burst frequency were measured continuously. Following IH, but not control, ventilation [5 L min-1 ; 95% confidence interval (CI) = 1-9] and MAP (5 mmHg; 95% CI = 1-9) were increased, whereas FVC (-0.2 mL min-1 mmHg-1 ; 95% CI = -0.0 to -0.4) and mean shear rate (-21.9 s-1 ; 95% CI = -5.8 to -38.0; all P < 0.05) were reduced. Systemic sNVT was increased following IH (0.25 mmHg burst-1 min-1 ; 95% CI = 0.01-0.49; P < 0.05), whereas changes in regional forearm sNVT were similar between IH and sham. Reductions in vessel wall shear stress and, consequently, nitric oxide production may contribute to heightened systemic sNVT and provide a potential neurovascular mechanism for elevated blood pressure in obstructive sleep apnoea.
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Affiliation(s)
- Troy J R Stuckless
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Tyler D Vermeulen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Courtney V Brown
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Denis J Wakeham
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Craig D Steinback
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Najib T Ayas
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - John S Floras
- University Health Network and Mount Sinai Hospital Division of Cardiology, Toronto, ON, Canada.,Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
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16
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Revol B, Jullian-Desayes I, Bailly S, Regnaut L, Tamisier R, Pepin JL, Joyeux-Faure M. What is the best treatment strategy for obstructive sleep apnoea-related hypertension? Hypertens Res 2018; 41:1070-1072. [PMID: 30323261 DOI: 10.1038/s41440-018-0114-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/05/2018] [Accepted: 07/08/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Bruno Revol
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France.,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France.,Pharmacovigilance Department, Grenoble Alpes University Hospital, Grenoble, France
| | - Ingrid Jullian-Desayes
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France. .,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France.
| | - Sébastien Bailly
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France.,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France
| | - Lucas Regnaut
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France.,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France
| | - Renaud Tamisier
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France.,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France
| | - Jean-Louis Pepin
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France. .,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France.
| | - Marie Joyeux-Faure
- HP2 Laboratory, INSERM U1042 Unit, Grenoble Alpes University, Grenoble, France.,Thorax and Vessels Division, Grenoble Alpes University Hospital, EFCR, Grenoble, France
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17
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Joyce K, Lucas S, Imray C, Balanos G, Wright AD. Advances in the available non-biological pharmacotherapy prevention and treatment of acute mountain sickness and high altitude cerebral and pulmonary oedema. Expert Opin Pharmacother 2018; 19:1891-1902. [DOI: 10.1080/14656566.2018.1528228] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- K.E. Joyce
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - S.J.E. Lucas
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - C.H.E. Imray
- Department of Vascular Surgery, University Hospitals of Coventry and Warwickshire; Warwick Medical School, Coventry, UK
| | - G.M Balanos
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - A. D. Wright
- Department of Medicine, University of Birmingham, Edgbaston, UK
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18
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Martínez VR, Aguirre MV, Todaro JS, Piro OE, Echeverría GA, Ferrer EG, Williams PAM. Azilsartan and its Zn(II) complex. Synthesis, anticancer mechanisms of action and binding to bovine serum albumin. Toxicol In Vitro 2018; 48:205-220. [PMID: 29408668 DOI: 10.1016/j.tiv.2018.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/15/2017] [Accepted: 01/14/2018] [Indexed: 02/08/2023]
Abstract
Azilsartan is the eighth approved member of angiotensin II receptor blockers for hypertension treatment. Considering that some drugs have additional effects when administered, we studied its effects and mechanisms of action on a human lung cancer cell line A549. We have also modified the structure of the drug by complexation with Zn(II) cation and assayed the anticancer effect. The crystal structure of the new binuclear Zn(II) complex, for short [Zn2(azil)2(H2O)4]·2H2O (ZnAzil), was determined by X-ray diffraction methods. The zinc ions are bridged by azilsartan ligands through their carboxylate oxygen and oxadiazol nitrogen atoms. The compounds were examined for their cytotoxic effects against human lung fibroblast (MRC5) and human lung cancer (A549) cell lines. Azilsartan displayed low cytotoxic effects at 150 μM concentrations in A549 human lung cancer cells but the higher effect measured for the Zn complex suggested that this compound may act as an anticancer agent. An apoptotic oxidative stress mechanism of action via the mitochondrial-dependent intrinsic pathway has been determined. Besides, the compounds exerted weak cytotoxic effects in the normal lung related cell line MRC5. Binding constants of the complex formed between each compound and bovine serum albumin (BSA) are in the intermediate range, hence suggesting that azilsartan and ZnAzil could be bonded and transported by BSA.
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Affiliation(s)
- Valeria R Martínez
- Centro de Química Inorgánica (CEQUINOR-CONICET-UNLP), 120 N° 1465, La Plata, Argentina
| | - María V Aguirre
- Laboratorio de Investigaciones Bioquímicas, Facultad de Medicina, UNNE, Moreno 1240, Corrientes, Argentina
| | - Juan S Todaro
- Laboratorio de Investigaciones Bioquímicas, Facultad de Medicina, UNNE, Moreno 1240, Corrientes, Argentina
| | - Oscar E Piro
- Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y IFLP (CONICET, CCT La Plata), C.C. 67, 1900 La Plata, Argentina
| | - Gustavo A Echeverría
- Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y IFLP (CONICET, CCT La Plata), C.C. 67, 1900 La Plata, Argentina
| | - Evelina G Ferrer
- Centro de Química Inorgánica (CEQUINOR-CONICET-UNLP), 120 N° 1465, La Plata, Argentina
| | - Patricia A M Williams
- Centro de Química Inorgánica (CEQUINOR-CONICET-UNLP), 120 N° 1465, La Plata, Argentina.
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19
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Gaur P, Saini S, Vats P, Kumar B. Regulation, signalling and functions of hormonal peptides in pulmonary vascular remodelling during hypoxia. Endocrine 2018; 59:466-480. [PMID: 29383676 DOI: 10.1007/s12020-018-1529-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 01/10/2018] [Indexed: 01/06/2023]
Abstract
Hypoxic state affects organism primarily by decreasing the amount of oxygen reaching the cells and tissues. To adjust with changing environment organism undergoes mechanisms which are necessary for acclimatization to hypoxic stress. Pulmonary vascular remodelling is one such mechanism controlled by hormonal peptides present in blood circulation for acclimatization. Activation of peptides regulates constriction and relaxation of blood vessels of pulmonary and systemic circulation. Thus, understanding of vascular tone maintenance and hypoxic pulmonary vasoconstriction like pathophysiological condition during hypoxia is of prime importance. Endothelin-1 (ET-1), atrial natriuretic peptide (ANP), and renin angiotensin system (RAS) function, their receptor functioning and signalling during hypoxia in different body parts point them as disease markers. In vivo and in vitro studies have helped understanding the mechanism of hormonal peptides for better acclimatization to hypoxic stress and interventions for better management of vascular remodelling in different models like cell, rat, and human is discussed in this review.
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Affiliation(s)
- Priya Gaur
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, India
| | - Supriya Saini
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, India
| | - Praveen Vats
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, India.
| | - Bhuvnesh Kumar
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, India
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20
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Khayat RN, Varadharaj S, Porter K, Sow A, Jarjoura D, Gavrilin MA, Zweier JL. Angiotensin Receptor Expression and Vascular Endothelial Dysfunction in Obstructive Sleep Apnea. Am J Hypertens 2018; 31:355-361. [PMID: 29036393 DOI: 10.1093/ajh/hpx174] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/25/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is associated with vascular endothelial dysfunction (VED) in otherwise healthy patients. The role of renin-angiotensin system (RAS) in the OSA induced VED is not well understood. METHODS Recently diagnosed OSA patients with very low cardiovascular disease (CVD) risk (Framingham score <5%) were studied at diagnosis and after 12 weeks of verified continuous positive airway pressure (CPAP) therapy. Participants underwent biopsy of gluteal subcutaneous tissue at baseline and after CPAP. Microcirculatory endothelial expression of angiotensin receptors type-1 (AT-1) and type-2 (AT-2) was measured in the subcutaneous tissue using quantitative confocal microscopy techniques. The ex-vivo effect of AT-1 receptor blockade (ARB) on endothelial superoxide production was also measured before and after CPAP treatment. RESULTS In OSA patients (n = 11), microcirculatory endothelial AT1 expression decreased from 873 (200) (fluorescence units) at baseline to 393 (59) units after 12 weeks of CPAP (P = 0.02). AT2 expression did not decrease significantly in these patients (479 (75) to 329 (58) post CPAP (P = 0.08)). The ex-vivo addition of the losartan to the microcirculatory endothelium resulted in decreased superoxide expression in the vascular walls from 14.2 (2.2) units to 4.2 (0.8) P < 0.001; while it had no effect on post-CPAP patient tissue (P = 0.64). CONCLUSIONS In OSA patients with no to minimal CVD risk, VED is associated with upregulation of AT-1 expression that is reversible with CPAP. Endothelial oxidative stress was reversible with ARB. RAS activation may play an important role in the development of early CVD risk in OSA patients.
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Affiliation(s)
- Rami N Khayat
- Department of Internal Medicine, The Sleep Heart Program, The Ohio State University, USA
- Division of Pulmonary Critical Care and Sleep, The Ohio State University, USA
| | - Saradhadevi Varadharaj
- Department of Internal Medicine, The Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, The Ohio State University, USA
| | - Kyle Porter
- The Center for Biostatistics, The Ohio State University, USA
| | - Angela Sow
- Department of Internal Medicine, The Sleep Heart Program, The Ohio State University, USA
- Department of Internal Medicine, The Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, The Ohio State University, USA
| | - David Jarjoura
- Department of Internal Medicine, The Sleep Heart Program, The Ohio State University, USA
| | - Mikhail A Gavrilin
- Division of Pulmonary Critical Care and Sleep, The Ohio State University, USA
| | - Jay L Zweier
- Department of Internal Medicine, The Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, The Ohio State University, USA
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21
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Khalyfa A, Youssefnia N, Foster GE, Beaudin AE, Qiao Z, Pialoux V, Pun M, Hanly PJ, Kheirandish-Gozal L, Poulin MJ, Gozal D. Plasma Exosomes and Improvements in Endothelial Function by Angiotensin 2 Type 1 Receptor or Cyclooxygenase 2 Blockade following Intermittent Hypoxia. Front Neurol 2017; 8:709. [PMID: 29312130 PMCID: PMC5743928 DOI: 10.3389/fneur.2017.00709] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/07/2017] [Indexed: 12/13/2022] Open
Abstract
Intermittent hypoxia (IH) is associated with increased endothelial dysfunction and cardiovascular disorders. Exosomes released in biological fluids may act as vehicles for propagating such damage, modifying the functional phenotype of endothelial cells. Drug interventions, however, may provide protection for the endothelium, in spite of exosomal activity. Using an experimental human model of IH, we investigated whether the beneficial effects of two drugs, celecoxib (CEL) and losartan (LOS), on IH-induced vascular dysfunction was mediated via exosomes or independent of IH-induced exosomal cargo alterations. We hypothesized that the beneficial effects of CEL and LOS on IH-induced vascular dysfunction would be mediated via modifications of exosomal properties by the drugs, rather than by direct effects of the drugs on the endothelium. Ten male volunteers were exposed to IH (single exposure of 6 h) while receiving LOS, CEL, or placebo (P) for 4 days before IH exposures, and plasma samples were obtained from which exosomes were isolated, and incubated with naïve human endothelial cell cultures either not treated or pretreated with LOS, CEL, or P. Functional reporter assays (monolayer impedance, monocyte adhesion, and eNOS phosphorylation) revealed that the degree of exosome-induced endothelial dysfunction was similar among IH-exposed subjects independent of drug treatment. However, pretreatment of naïve endothelial cells with LOS or CEL before addition of exosomes from IH-exposed subjects afforded significant protection. Thus, the cardiovascular protective impact of LOS and CEL appears to be mediated by their direct effects on endothelial cells, rather than via modulation of exosomal cargo.
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Affiliation(s)
- Abdelnaby Khalyfa
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, University of Chicago, Chicago, IL, United States
| | - Nina Youssefnia
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, University of Chicago, Chicago, IL, United States
| | - Glen E Foster
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Andrew E Beaudin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Zhuanghong Qiao
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, University of Chicago, Chicago, IL, United States
| | - Vincent Pialoux
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Matiram Pun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Patrick J Hanly
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Leila Kheirandish-Gozal
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, University of Chicago, Chicago, IL, United States
| | - Marc J Poulin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.,Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - David Gozal
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, University of Chicago, Chicago, IL, United States
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Laouafa S, Ribon-Demars A, Marcouiller F, Roussel D, Bairam A, Pialoux V, Joseph V. Estradiol Protects Against Cardiorespiratory Dysfunctions and Oxidative Stress in Intermittent Hypoxia. Sleep 2017. [PMID: 28633495 DOI: 10.1093/sleep/zsx104] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Study Objectives We tested the hypothesis that estradiol (E2) protects against cardiorespiratory disorders and oxidative stress induced by chronic intermittent hypoxia (CIH) in adult female rats. Methods Sprague-Dawley female rats (230-250 g) were ovariectomized and implanted with osmotic pumps delivering vehicle or E2 (0.5 mg/kg/d). After 14 days of recovery, the rats were exposed to CIH (21%-10% O2: 8 h/d, 10 cycles per hour) or room air (RA). After 7 days of CIH or RA exposure, we measured arterial pressures (tail cuff), metabolic rate (indirect calorimetry), minute ventilation, the frequency of sighs and apneas at rest, and ventilatory responses to hypoxia and hypercapnia (whole body plethysmography). We collected the cerebral cortex, brainstem, and adrenal glands to measure the activity of NADPH and xanthine oxidase (pro-oxidant enzymes), glutathione peroxidase, and the mitochondrial and cytosolic superoxide dismutase (antioxidant enzymes) and measured lipid peroxidation and advanced oxidation protein products (markers of oxidative stress). Results CIH increased arterial pressure, the frequency of apnea at rest, and the hypoxic and hypercapnic ventilatory responses and reduced metabolic rate. CIH also increased oxidant enzyme activities and decreased antioxidant activity in the cortex. E2 treatment reduced body weight and prevented the effects of CIH. Conclusions E2 prevents cardiorespiratory disorders and oxidative stress induced by CIH. These observations may help to better understand the underlying mechanisms linking menopause and occurrence of sleep apnea in women and highlight a potential advantage of hormone therapy.
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Affiliation(s)
- Sofien Laouafa
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada.,CNRS, UMR 5023, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Alexandra Ribon-Demars
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada.,Univ Lyon, Université Claude Bernard Lyon 1, Laboratoire interuniversitaire de biologie de la motricité EA7424, Villeurbanne, France
| | - François Marcouiller
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Damien Roussel
- CNRS, UMR 5023, Universite´ Claude Bernard Lyon 1, Villeurbanne, France
| | - Aida Bairam
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Vincent Pialoux
- Univ Lyon, Université Claude Bernard Lyon 1, Laboratoire interuniversitaire de biologie de la motricité EA7424, Villeurbanne, France.,Institut Universitaire de France, Paris, France
| | - Vincent Joseph
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
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23
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Beaudin AE, Hartmann SE, Pun M, Poulin MJ. Human cerebral blood flow control during hypoxia: focus on chronic pulmonary obstructive disease and obstructive sleep apnea. J Appl Physiol (1985) 2017; 123:1350-1361. [DOI: 10.1152/japplphysiol.00352.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/01/2017] [Accepted: 08/07/2017] [Indexed: 01/06/2023] Open
Abstract
The brain is a vital organ that relies on a constant and adequate blood flow to match oxygen and glucose delivery with the local metabolic demands of active neurons. Thus exquisite regulation of cerebral blood flow (CBF) is particularly important under hypoxic conditions to prevent a detrimental decrease in the partial pressure of oxygen within the brain tissues. Cerebrovascular sensitivity to hypoxia, assessed as the change in CBF during a hypoxic challenge, represents the capacity of cerebral vessels to respond to, and compensate for, a reduced oxygen supply, and has been shown to be impaired or blunted in a number of conditions. For instance, this is observed with aging, and in clinical conditions such as untreated obstructive sleep apnea (OSA) and in healthy humans exposed to intermittent hypoxia. This review will 1) provide a brief overview of cerebral blood flow regulation and results of pharmacological intervention studies which we have performed to better elucidate the basic mechanisms of cerebrovascular regulation in humans; and 2) present data from studies in clinical and healthy populations, using a translational physiology approach, to investigate human CBF control during hypoxia. Results from studies in patients with chronic obstructive pulmonary disease and OSA will be presented to identify the effects of the disease processes on cerebrovascular sensitivity to hypoxia. Data emerging from experimental human models of intermittent hypoxia during wakefulness will also be reviewed to highlight the effects of intermittent hypoxia on the brain.
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Affiliation(s)
- Andrew E. Beaudin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sara E. Hartmann
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Matiram Pun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Marc J. Poulin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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24
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Jouett NP, Moralez G, Raven PB, Smith ML. Losartan reduces the immediate and sustained increases in muscle sympathetic nerve activity after hyperacute intermittent hypoxia. J Appl Physiol (1985) 2017; 122:884-892. [DOI: 10.1152/japplphysiol.00683.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/21/2016] [Accepted: 01/08/2017] [Indexed: 11/22/2022] Open
Abstract
Obstructive sleep apnea (OSA) is characterized by intermittent hypoxemia, which produces elevations in sympathetic nerve activity (SNA) and associated hypertension in experimental models that persist beyond the initial exposure. We tested the hypotheses that angiotensin receptor blockade in humans using losartan attenuates the immediate and immediately persistent increases in 1) SNA discharge and 2) mean arterial pressure (MAP) after hyperacute intermittent hypoxia training (IHT) using a randomized, placebo-controlled, repeated-measures experimental design. We measured ECG and photoplethysmographic arterial pressure in nine healthy human subjects, while muscle SNA (MSNA) was recorded in seven subjects using microneurography. Subjects were exposed to a series of hypoxic apneas in which they inhaled two to three breaths of nitrogen, followed by a 20-s apnea and 40 s of room air breathing every minute for 20 min. Hyperacute IHT produced substantial and persistent elevations in MSNA burst frequency (baseline: 15.3 ± 1.8, IHT: 24 ± 1.5, post-IHT 20.0 ± 1.3 bursts/min, all P < 0.01) and MAP (baseline: 89.2 ± 3.3, IHT: 92.62 ± 3.1, post-IHT: 93.83 ± 3.1 mmHg, all P < 0.02). Losartan attenuated the immediate and sustained increases in MSNA (baseline: 17.3 ± 2.5, IHT: 18.6 ± 2.2, post-IHT 20.0 ± 1.3 bursts/min, all P < 0.001) and MAP (baseline: 81.9 ± 2.6, IHT: 81.1 ± 2.8, post-IHT: 81.3 ± 3.0 mmHg, all P > 0.70). This investigation confirms the role of angiotensin II type 1a receptors in the immediate and persistent sympathoexcitatory and pressor responses to IHT. NEW & NOTEWORTHY This study demonstrates for the first time in humans that losartan, an angiotensin receptor blocker (ARB), abrogates the acute and immediately persistent increases in muscle sympathetic nerve activity and arterial pressure in response to acute intermittent hypoxia. This investigation, along with others, provides important beginning translational evidence for using ARBs in treatment of the intermittent hypoxia observed in obstructive sleep apnea patients.
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Affiliation(s)
- Noah P. Jouett
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, Texas; and
| | - Gilbert Moralez
- Institute for Environmental and Exercise Medicine, Texas Health Presbyterian Hospital, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Peter B. Raven
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, Texas; and
| | - Michael L. Smith
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, Texas; and
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25
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Chen TI, Chen MYC. Zinc Is Indispensable in Exercise-Induced Cardioprotection against Intermittent Hypoxia-Induced Left Ventricular Function Impairment in Rats. PLoS One 2016; 11:e0168600. [PMID: 27977796 PMCID: PMC5158066 DOI: 10.1371/journal.pone.0168600] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/03/2016] [Indexed: 01/19/2023] Open
Abstract
In obstructive sleep apnea (OSA), recurrent obstruction of the upper airway leads to intermittent hypoxia (IH) during sleep, which can result in impairment of cardiac function. Although exercise can have beneficial effects against IH-induced cardiac dysfunction, the mechanism remains unclear. This study aimed to investigate the interactions of zinc and exercise on IH-triggered left ventricular dysfunction in a rat model that mimics IH in OSA patients. Nine-week-old male Sprague-Dawley rats were randomly assigned to either a control group (CON) or to a group receiving 10 weeks of exercise training (EXE). During weeks 9 and 10, half the rats in each group were subjected to IH for 8 h per day for 14 days (IHCON, IHEXE), whereas the remainder continued to breathe room air. Rats within each of the CON, IHCON, EXE, and IHEXE groups were further randomly assigned to receive intraperitoneal injections of either zinc chloride, the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN), or injection vehicle only. IH induced a lower left ventricular fractional shortening, reduced ejection fraction, higher myocardial levels of inflammatory factors, increased levels oxidative stress, and lower levels of antioxidative capacity, all of which were abolished by zinc treatment. IHEXE rats exhibited higher levels of cardiac function and antioxidant capacity and lower levels of inflammatory factors and oxidative stress than IHCON rats; however, IHEXE rats receiving TPEN did not exhibit these better outcomes. In conclusion, zinc is required for protecting against IH-induced LV functional impairment and likely plays a critical role in exercise-induced cardioprotection by exerting a dual antioxidant and anti-inflammatory effect.
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Affiliation(s)
- Tsung-I Chen
- Center of Physical Education, Office of General and Basic Education, Tzu Chi University, Hualien, Taiwan
- * E-mail:
| | - Michael Yu-Chih Chen
- Department of Cardiology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
- PhD Program in Institute of Medicine, Tzu Chi University, Hualien, Taiwan
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26
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Tremblay JC, Boulet LM, Tymko MM, Foster GE. Intermittent hypoxia and arterial blood pressure control in humans: role of the peripheral vasculature and carotid baroreflex. Am J Physiol Heart Circ Physiol 2016; 311:H699-706. [PMID: 27402667 DOI: 10.1152/ajpheart.00388.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/06/2016] [Indexed: 11/22/2022]
Abstract
Intermittent hypoxia (IH) occurs in association with obstructive sleep apnea and likely contributes to the pathogenesis of hypertension. The purpose of this study was to examine the putative early adaptations at the level of the peripheral vasculature and carotid baroreflex (CBR) that may promote the development of hypertension. Ten healthy male participants (26 ± 1 yr, BMI = 24 ± 1 kg/m(2)) were exposed to 6 h of IH (1-min cycles of normoxia and hypoxia) and SHAM in a single-blinded, counterbalanced crossover study design. Ambulatory blood pressure was measured during each condition and the following night. Vascular strain of the carotid and femoral artery, a measure of localized arterial stiffness, and hemodynamic shear patterns in the brachial and femoral arteries were measured during each condition. Brachial artery reactive hyperemia flow-mediated vasodilation was assessed before and after each condition as a measure of endothelial function. CBR function and its control over leg vascular conductance (LVC) were measured after each condition with a variable-pressure neck chamber. Intermittent hypoxia 1) increased nighttime pulse pressure by 3.2 ± 1.3 mmHg, 2) altered femoral but not brachial artery hemodynamics, 3) did not affect brachial artery endothelial function, 4) reduced vascular strain in the carotid and possibly femoral artery, and 5) shifted CBR mean arterial pressure (MAP) to higher MAP while blunting LVC responses to CBR loading. These results suggest limb-specific vascular impairments, reduced vascular strain, and CBR resetting combined with blunted LVC responses are factors in the early pathogenesis of IH-induced development of hypertension.
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Affiliation(s)
- Joshua C Tremblay
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Michael M Tymko
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
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27
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Jouett NP, Moralez G, White DW, Eubank WL, Chen S, Tian J, Smith ML, Zimmerman MC, Raven PB. N-Acetylcysteine reduces hyperacute intermittent hypoxia-induced sympathoexcitation in human subjects. Exp Physiol 2016; 101:387-96. [PMID: 27027616 DOI: 10.1113/ep085546] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/12/2016] [Indexed: 01/31/2023]
Abstract
NEW FINDINGS What is the central question of this study? This study evaluated the following central question: does N-acetylcysteine (N-AC), an antioxidant that readily penetrates the blood-brain barrier, have the capability to reduce the increase in sympathetic nerve activity observed during hyperacute intermittent hypoxia? What is the main finding and its importance? We demonstrate that N-AC decreases muscle sympathetic nerve activity in response to hyperacute intermittent hypoxia versus placebo control. This finding suggests that antioxidants, such as N-AC, have therapeutic potential in obstructive sleep apnoea. This investigation tested the following hypotheses: that (i) N-acetylcysteine (N-AC) attenuates hyperacute intermittent hypoxia-induced sympathoexcitation, (ii) without elevating superoxide measured in peripheral venous blood. Twenty-eight healthy human subjects were recruited to the study. One hour before experimentation, each subject randomly ingested either 70 mg kg(-1) of N-AC (n = 16) or vehicle placebo (n = 12). Three-lead ECG and arterial blood pressure, muscle sympathetic nerve activity (n = 17) and whole-blood superoxide concentration (using electron paramagnetic resonance spectroscopy; n = 12) were measured. Subjects underwent a 20 min hyperacute intermittent hypoxia training (hAIHT) protocol that consisted of cyclical end-expiratory apnoeas with 100% nitrogen. N-AC decreased muscle sympathetic nerve activity after hAIHT compared with placebo (P < 0.02). However, N-AC did not alter superoxide concentrations in venous blood compared with placebo (P > 0.05). Moreover, hAIHT did not increase superoxide concentrations in the peripheral circulation as measured by electron paramagnetic resonance (P > 0.05). Based on these findings, we contend that (i) hAIHT and (ii) the actions of N-AC in hAIHT are primarily mediated centrally rather than peripherally, although central measurements of reactive oxygen species are difficult to obtain in human subjects, thus making this assertion difficult to verify. This investigation suggests the possibility of developing a pharmaceutical therapy to inhibit the sympathoexcitation associated with obstructive sleep apnoea.
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Affiliation(s)
- Noah P Jouett
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Gilbert Moralez
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Daniel W White
- Integrative Physiology Laboratory, Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL, USA
| | - Wendy L Eubank
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Shande Chen
- Department of Biostatistics and Epidemiology, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Jun Tian
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michael L Smith
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Matthew C Zimmerman
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Peter B Raven
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, TX, USA
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28
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Weiss JW, Tamisier R, Liu Y. Sympathoexcitation and arterial hypertension associated with obstructive sleep apnea and cyclic intermittent hypoxia. J Appl Physiol (1985) 2015; 119:1449-54. [PMID: 26251511 DOI: 10.1152/japplphysiol.00315.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/03/2015] [Indexed: 12/15/2022] Open
Abstract
Obstructive sleep apnea (OSA) is characterized by repetitive episodes of upper airway obstruction during sleep. These obstructive episodes are characterized by cyclic intermittent hypoxia (CIH), by sleep fragmentation, and by hemodynamic instability, and they result in sustained sympathoexcitation and elevated arterial pressure that persist during waking, after restoration of normoxia. Early studies established that 1) CIH, rather than sleep disruption, accounts for the increase in arterial pressure; 2) the increase in arterial pressure is a consequence of the sympathoactivation; and 3) arterial hypertension after CIH exposure requires an intact peripheral chemoreflex. More recently, however, evidence has accumulated that sympathoactivation and hypertension after CIH are also dependent on altered central sympathoregulation. Furthermore, although many molecular pathways are activated in both the carotid chemoreceptor and in the central nervous system by CIH exposure, two specific neuromodulators-endothelin-1 and angiotensin II-appear to play crucial roles in mediating the sympathetic and hemodynamic response to intermittent hypoxia.
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Affiliation(s)
- J Woodrow Weiss
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts;
| | - Renaud Tamisier
- Sleep Laboratory and EFCR, Pôle Rééducation et Physiologie, University Hospital, HP2 Laboratory (Hypoxia: Pathophysiology) INSERM ERI 17, EA 3745 Joseph Fourier University, Grenoble, France; and
| | - Yuzhen Liu
- First Afflicted Hospital of Xinxiang Medical University, Xinxiang, Henan, China
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29
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Shang J, Guo XL, Deng Y, Yuan X, Liu HG. Regulatory effects of AT₁R-TRAF6-MAPKs signaling on proliferation of intermittent hypoxia-induced human umbilical vein endothelial cells. ACTA ACUST UNITED AC 2015. [PMID: 26223916 DOI: 10.1007/s11596-015-1459-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Endothelial dysfunction induced by intermittent hypoxia (IH) participates in obstructive sleep apnea syndrome (OSAS)-associated cardiovascular disorders. Myeloid differentiation primary response 88 (MyD88) and tumor necrosis factor receptor-associated factor 6 (TRAF6) regulate numerous downstream adaptors like mitogen-activated protein kinases (MAPKs) and the subsequent oxidative stress and inflammatory responses. This study aimed to characterize the role of MyD88/TRAF6 in IH-treated cell function and its associated signaling. Human umbilical vein endothelial cells (HUVECs) were randomly exposed to IH or normoxia for 0, 2, 4 and 6 h. Western blotting was used to detect the expression pattern of target gene proteins [angiotensin 1 receptor (AT1R), p-ERK1/2, p-p38MAPK, MyD88 and TRAF6], and the relationships among these target genes down-regulated by the corresponding inhibitors were studied. Finally, the influence of these target genes on proliferation of HUVECs was also assessed by EdU analysis. Protein levels of AT1R, TRAF6 and p-ERK1/2 were increased after IH exposure, with a slight rise in MyD88 and a dynamic change in p-p38MAPK. The down-regulation of TRAF6 by siRNA reduced ERK1/2 phosphorylation during IH without any effects on AT1R. Blockade of AT1R with valsartan decreased TRAF6 and p-ERK1/2 protein expression after IH exposure. ERK1/2 inhibition with PD98059 suppressed only AT1R expression. IH promoted HUVECs proliferation, which was significantly suppressed by the inhibition of TRAF6, AT1R and ERK1/2. The findings demonstrate that TRAF6 regulates the proliferation of HUVECs exposed to short-term IH by modulating cell signaling involving ERK1/2 downstream of AT1R. Targeting the AT1R-TRAF6-p-ERK1/2 signaling pathway might be helpful in restoring endothelial function.
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Affiliation(s)
- Jin Shang
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Respiratory Disease of the Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xue-Ling Guo
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Respiratory Disease of the Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yan Deng
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Respiratory Disease of the Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiao Yuan
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Respiratory Disease of the Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hui-Guo Liu
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Respiratory Disease of the Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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30
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Abstract
We address adaptive vs. maladaptive responses to hypoxemia in healthy humans and hypoxic-tolerant species during wakefulness, sleep, and exercise. Types of hypoxemia discussed include short-term and life-long residence at high altitudes, the intermittent hypoxemia attending sleep apnea, or training regimens prescribed for endurance athletes. We propose that hypoxia presents an insult to O2 transport, which is poorly tolerated in most humans because of the physiological cost.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Barbara J Morgan
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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31
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Beaudin AE, Waltz X, Pun M, Wynne-Edwards KE, Ahmed SB, Anderson TJ, Hanly PJ, Poulin MJ. Human intermittent hypoxia-induced respiratory plasticity is not caused by inflammation. Eur Respir J 2015; 46:1072-83. [PMID: 26065565 DOI: 10.1183/09031936.00007415] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/19/2015] [Indexed: 11/05/2022]
Abstract
Ventilatory instability, reflected by enhanced acute hypoxic (AHVR) and hypercapnic (AHCVR) ventilatory responses is a fundamental component of obstructive sleep apnoea (OSA) pathogenesis. Intermittent hypoxia-induced inflammation is postulated to promote AHVR enhancement in OSA, although the role of inflammation in intermittent hypoxia-induced respiratory changes in humans has not been examined. Thus, this study assessed the role of inflammation in intermittent hypoxia-induced respiratory plasticity in healthy humans.In a double-blind, placebo-controlled, randomised crossover study design, 12 males were exposed to 6 h of intermittent hypoxia on three occasions. Prior to intermittent hypoxia exposures, participants ingested (for 4 days) either placebo or the nonsteroidal anti-inflammatory drugs indomethacin (nonselective cyclooxygenase (COX) inhibitor) and celecoxib (selective COX-2 inhibitor). Pre- and post-intermittent hypoxia resting ventilation, AHVR, AHCVR and serum concentration of the pro-inflammatory cytokine tumour necrosis factor (TNF)-α were assessed.Pre-intermittent hypoxia resting ventilation, AHVR, AHCVR and TNF-α concentrations were similar across all three conditions (p≥0.093). Intermittent hypoxia increased resting ventilation and the AHVR similarly across all conditions (p=0.827), while the AHCVR was increased (p=0.003) and TNF-α was decreased (p=0.006) with only selective COX-2 inhibition.These findings indicate that inflammation does not contribute to human intermittent hypoxia-induced respiratory plasticity. Moreover, selective COX-2 inhibition augmented the AHCVR following intermittent hypoxia exposure, suggesting that selective COX-2 inhibition could exacerbate OSA severity by increasing ventilatory instability.
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Affiliation(s)
- Andrew E Beaudin
- Dept of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Xavier Waltz
- Dept of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Matiram Pun
- Dept of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Katherine E Wynne-Edwards
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Sofia B Ahmed
- Dept of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Todd J Anderson
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Dept of Cardiac Science, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Patrick J Hanly
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Dept of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Sleep Centre, Foothills Medical Centre, Calgary, AB, Canada
| | - Marc J Poulin
- Dept of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Dept of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
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32
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Expressions of angiotensin and cytokine receptors in the paracrine signaling of the carotid body in hypoxia and sleep apnea. Respir Physiol Neurobiol 2015; 209:6-12. [DOI: 10.1016/j.resp.2014.09.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/18/2014] [Accepted: 09/22/2014] [Indexed: 01/27/2023]
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33
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Nakane H, Kamouchi M, Hata J, Ibayashi S, Kusuda K, Omae T, Nagao T, Ago T, Kitazono T. Effects of hydrochlorothiazide on oxidative stress and pulse pressure in hypertensive patients with chronic stroke: the EMINENT study. Intern Med 2015; 54:573-7. [PMID: 25790807 DOI: 10.2169/internalmedicine.54.2631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE Thiazide diuretics are reported to have antioxidant effects and reduce pulse pressure (PP). The aim of this study was to elucidate whether hydrochlorothiazide additionally exerts such effects in stroke patients under treatment with losartan. METHODS This study was an open-label, randomized, multicenter study. Patients with a history of chronic stroke and treatment with angiotensin receptor blockers or angiotensin-converting enzyme inhibitors for essential hypertension were enrolled. Fifty-five hypertensive patients were randomly assigned to two groups: those further treated with hydrochlorothiazide and those further treated with non-diuretic antihypertensive drugs. RESULTS Both groups showed a significant decrease in PP over six months (hydrochlorothiazide group: 67±12 mmHg to 58±12, p<0.001; non-diuretic group: 72±12 to 61±12, p<0.001), although no significant differences were observed between the two groups. The malondialdehyde-modified low-density lipoprotein levels did not change significantly after treatment in either group. CONCLUSION In this study, hydrochlorothiazide treatment did not provide any additional benefits over non-diuretic antihypertensive drugs in terms of antioxidant effects or reducing PP.
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Affiliation(s)
- Hiroshi Nakane
- Cerebrovascular and Neurology Center, Cerebrovascular Division, National Hospital Organization Fukuoka Higashi Medical Center, Japan
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Fung ML. The role of local renin-angiotensin system in arterial chemoreceptors in sleep-breathing disorders. Front Physiol 2014; 5:336. [PMID: 25249981 PMCID: PMC4155775 DOI: 10.3389/fphys.2014.00336] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/15/2014] [Indexed: 11/23/2022] Open
Abstract
The renin-angiotensin system (RAS) plays pivotal roles in the regulation of cardiovascular and renal functions to maintain the fluid and electrolyte homeostasis. Experimental studies have demonstrated a locally expressed RAS in the carotid body, which is functional significant in the effect of angiotensin peptides on the regulation of the activity of peripheral chemoreceptors and the chemoreflex. The physiological and pathophysiological implications of the RAS in the carotid body have been proposed upon recent studies showing a significant upregulation of the RAS expression under hypoxic conditions relevant to altitude acclimation and sleep apnea and also in animal model of heart failure. Specifically, the increased expression of angiotensinogen, angiotensin-converting enzyme and angiotensin AT1 receptors plays significant roles in the augmented carotid chemoreceptor activity and inflammation of the carotid body. This review aims to summarize these results with highlights on the pathophysiological function of the RAS under hypoxic conditions. It is concluded that the maladaptive changes of the RAS in the carotid body plays a pathogenic role in sleep apnea and heart failure, which could potentially be a therapeutic target for the treatment of the pathophysiological consequence of sleep apnea.
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Affiliation(s)
- Man Lung Fung
- Department of Physiology, University of Hong Kong Pokfulam, Hong Kong
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Beaudin AE, Pun M, Yang C, Nicholl DDM, Steinback CD, Slater DM, Wynne-Edwards KE, Hanly PJ, Ahmed SB, Poulin MJ. Cyclooxygenases 1 and 2 differentially regulate blood pressure and cerebrovascular responses to acute and chronic intermittent hypoxia: implications for sleep apnea. J Am Heart Assoc 2014; 3:e000875. [PMID: 24815497 PMCID: PMC4309085 DOI: 10.1161/jaha.114.000875] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Background Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular and cerebrovascular disease resulting from intermittent hypoxia (IH)‐induced inflammation. Cyclooxygenase (COX)‐formed prostanoids mediate the inflammatory response, and regulate blood pressure and cerebral blood flow (CBF), but their role in blood pressure and CBF responses to IH is unknown. Therefore, this study's objective was to determine the role of prostanoids in cardiovascular and cerebrovascular responses to IH. Methods and Results Twelve healthy, male participants underwent three, 6‐hour IH exposures. For 4 days before each IH exposure, participants ingested a placebo, indomethacin (nonselective COX inhibitor), or Celebrex® (selective COX‐2 inhibitor) in a double‐blind, randomized, crossover study design. Pre‐ and post‐IH blood pressure, CBF, and urinary prostanoids were assessed. Additionally, blood pressure and urinary prostanoids were assessed in newly diagnosed, untreated OSA patients (n=33). Nonselective COX inhibition increased pre‐IH blood pressure (P≤0.04) and decreased pre‐IH CBF (P=0.04) while neither physiological variable was affected by COX‐2 inhibition (P≥0.90). Post‐IH, MAP was elevated (P≤0.05) and CBF was unchanged with placebo and nonselective COX inhibition. Selective COX‐2 inhibition abrogated the IH‐induced MAP increase (P=0.19), but resulted in lower post‐IH CBF (P=0.01). Prostanoids were unaffected by IH, except prostaglandin E2 was elevated with the placebo (P=0.02). Finally, OSA patients had elevated blood pressure (P≤0.4) and COX‐1 formed thromboxane A2 concentrations (P=0.02). Conclusions COX‐2 and COX‐1 have divergent roles in modulating vascular responses to acute and chronic IH. Moreover, COX‐1 inhibition may mitigate cardiovascular and cerebrovascular morbidity in OSA. Clinical Trial Registration URL: www.clinicaltrials.gov. Unique identifier: NCT01280006
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Affiliation(s)
- Andrew E Beaudin
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
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Dempsey JA, Powell FL, Bisgard GE, Blain GM, Poulin MJ, Smith CA. Role of chemoreception in cardiorespiratory acclimatization to, and deacclimatization from, hypoxia. J Appl Physiol (1985) 2013; 116:858-66. [PMID: 24371017 DOI: 10.1152/japplphysiol.01126.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During sojourn to high altitudes, progressive time-dependent increases occur in ventilation and in sympathetic nerve activity over several days, and these increases persist upon acute restoration of normoxia. We discuss evidence concerning potential mediators of these changes, including the following: 1) correction of alkalinity in cerebrospinal fluid; 2) increased sensitivity of carotid chemoreceptors; and 3) augmented translation of carotid chemoreceptor input (at the level of the central nervous system) into increased respiratory motor output via sensitization of hypoxic sensitive neurons in the central nervous system and/or an interdependence of central chemoreceptor responsiveness on peripheral chemoreceptor sensory input. The pros and cons of chemoreceptor sensitization and cardiorespiratory acclimatization to hypoxia and intermittent hypoxemia are also discussed in terms of their influences on arterial oxygenation, the work of breathing, sympathoexcitation, systemic blood pressure, and exercise performance. We propose that these adaptive processes may have negative implications for the cardiovascular health of patients with sleep apnea and perhaps even for athletes undergoing regimens of "sleep high-train low"!
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Dempsey JA, Xie A, Patz DS, Wang D. Physiology in medicine: obstructive sleep apnea pathogenesis and treatment--considerations beyond airway anatomy. J Appl Physiol (1985) 2013; 116:3-12. [PMID: 24201709 DOI: 10.1152/japplphysiol.01054.2013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We review evidence in support of significant contributions to the pathogenesis of obstructive sleep apnea (OSA) from pathophysiological factors beyond the well-accepted importance of airway anatomy. Emphasis is placed on contributions from neurochemical control of central respiratory motor output through its effects on output stability, upper airway dilator muscle activation, and arousability. In turn, we consider the evidence demonstrating effective treatment of OSA via approaches that address each of these pathophysiologic risk factors. Finally, a case is made for combining treatments aimed at both anatomical and ventilatory control system deficiencies and for individualizing treatment to address a patient's own specific risk factors.
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Affiliation(s)
- Jerome A Dempsey
- James B. Skatrud Laboratory of Pulmonary & Sleep Medicine, Middleton Veterans Administration Hospital and Department of Population Health Sciences, University of Wisconsin-Madison, Madison Wisconsin
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Lam SY, Liu Y, Ng KM, Liong EC, Tipoe GL, Leung PS, Fung ML. Upregulation of a local renin-angiotensin system in the rat carotid body during chronic intermittent hypoxia. Exp Physiol 2013; 99:220-31. [PMID: 24036592 DOI: 10.1113/expphysiol.2013.074591] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The carotid body (CB) plays an important role in the alteration of cardiorespiratory activity in chronic intermittent hypoxia (IH) associated with sleep-disordered breathing, which may be mediated by local expression of the renin-angiotensin system (RAS). We hypothesized a pathogenic role for IH-induced RAS expression in the CB. The CB expression of RAS components was examined in rats exposed to IH resembling a severe sleep-apnoeic condition for 7 days. In situ hybridization showed an elevated expression of angiotensinogen in the CB glomus cells in the hypoxic group when compared with the normoxic control group. Immunohistochemical studies and Western blot analysis revealed increases in the protein level of both angiotensinogen and angiotensin II type 1 (AT1) receptors in the hypoxic group, which were localized to the glomic clusters containing tyrosine hydroxylase. RT-PCR studies confirmed that levels of the mRNA expression of angiotensinogen, angiotensin-converting enzyme, AT1a and AT2 receptors were significantly increased in the CBs of the hypoxic rats. Functionally, the [Ca(2+)]i response to exogenous angiotensin II was enhanced in fura-2-loaded glomus cells dissociated from hypoxic rats when compared with those of the normoxic control animals. Pretreatment with losartan, but not PD123319, abolished the angiotensin II-induced [Ca(2+)]i response, suggesting an involvement of AT1 receptors. Moreover, daily treatment of the IH group of rats with losartan attenuated the levels of oxidative stress, gp91(phox) expression and macrophage infiltration in the CB. Collectively, the upregulated local RAS expression could play a pathogenic role in the augmented CB activity and local inflammation via AT1 receptor activation during IH conditions in patients with sleep-disordered breathing.
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Affiliation(s)
- Siu-Yin Lam
- M. L. Fung: Department of Physiology, University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
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Li FCH, Li BPT, Wu JCC, Chang AYW. Transition from oxidative stress to nitrosative stress in rostral ventrolateral medulla underlies fatal intoxication induced by organophosphate mevinphos. Toxicol Sci 2013; 135:202-17. [PMID: 23824088 DOI: 10.1093/toxsci/kft147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
As the most widely used pesticides in the world, fatal incidence of suicidal poisoning by organophosphate compounds is high and is often associated with cardiovascular toxicity. Using the pesticide mevinphos as our tool, we investigated the roles of oxidative stress and nitrosative stress at the rostral ventrolateral medulla (RVLM), the brain stem site that maintains arterial pressure (AP) and sympathetic vasomotor tone, in the cardiovascular depressive effects of organophosphate poisons. Microinjection of mevinphos (10 nmol) into the RVLM of anesthetized Sprague-Dawley rats induced progressive hypotension that was accompanied by an increase (phase I), followed by a decrease (phase II) of an experimental index of baroreflex-mediated sympathetic vasomotor tone, with a fatality rate of 35%. During phase I, there was a preferential upregulation of angiotensin type I receptor (AT1R) messenger RNA (mRNA) and protein that leads to activation of NADPH oxidase (Nox) and increase in superoxide at the RVLM. Pharmacological antagonism of these signals exacerbated fatality and shorted survival time by eliminating baroreflex-mediated sympathetic vasomotor tone, AP, and heart rate. During phase II, there was a progressive upregulation of angiotensin type II receptor (AT2R) mRNA and protein that leads to increase in peroxynitrite in the RVLM, blockade of both sustained brain stem cardiovascular regulation and improved survival. We further found that AT1R and AT2R cross-interacted at transcriptional and signaling levels in the RVLM. We conclude that a transition from AT1R-mediated oxidative stress to AT2R-mediated nitrosative stress in the RVLM underlies the shift from sustained to impaired brain stem cardiovascular regulation that underpins cardiovascular fatality during mevinphos intoxication.
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Affiliation(s)
- Faith C H Li
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
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Faiss R, Pialoux V, Sartori C, Faes C, Dériaz O, Millet GP. Ventilation, oxidative stress, and nitric oxide in hypobaric versus normobaric hypoxia. Med Sci Sports Exerc 2013; 45:253-60. [PMID: 22895381 DOI: 10.1249/mss.0b013e31826d5aa2] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE Slight differences in physiological responses and nitric oxide (NO) have been reported at rest between hypobaric hypoxia (HH) and normobaric hypoxia (NH) during short exposure.Our study reports NO and oxidative stress at rest and physiological responses during moderate exercise in HH versus NH. METHODS Ten subjects were randomly exposed for 24 h to HH (3000 m; FIO2, 20.9%; BP, 530 ± 6 mm Hg) or to NH (FIO2, 14.7%; BP, 720 ± 1 mm Hg). Before and every 8 h during the hypoxic exposures, pulse oxygen saturation (SpO2), HR, and gas exchanges were measured during a 6-min submaximal cycling exercise. At rest, the partial pressure of exhaled NO, blood nitrate and nitrite (NOx), plasma levels of oxidative stress, and pH levels were additionally measured. RESULTS During exercise, minute ventilation was lower in HH compared with NH (-13% after 8 h, P < 0.05). End-tidal CO2 pressure was lower (P < 0.01) than PRE both in HH and NH but decreased less in HH than that in NH (-25% vs. -37%, P < 0.05).At rest, exhaled NO and NOx decreased in HH (-46% and -36% after 24 h, respectively, P < 0.05) whereas stable in NH. By contrast, oxidative stress was higher in HH than that in NH after 24 h (P < 0.05). The plasma pH level was stable in HH but increased in NH (P < 0.01). When compared with prenormoxic values, SpO2, HR, oxygen consumption, breathing frequency, and end-tidal O2 pressure showed similar changes in HH and NH. CONCLUSION Lower ventilatory responses to a similar hypoxic stimulus during rest and exercise in HH versus NH were sustained for 24 h and associated with lower plasma pH level, exaggerated oxidative stress, and impaired NO bioavailability.
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Affiliation(s)
- Raphael Faiss
- Faculty of Biology and Medicine, ISSUL, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland.
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Mirrakhimov AE. Supine fluid redistribution: should we consider this as an important risk factor for obstructive sleep apnea? Sleep Breath 2012; 17:511-23. [PMID: 22872284 DOI: 10.1007/s11325-012-0755-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 06/26/2012] [Accepted: 07/15/2012] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Obstructive sleep apnea (OSA) is a common medical disorder affecting at least 2 % of women and 4 % of men living in Western societies. Obesity, older age, male gender, alcohol and sedative use, smoking, craniofacial parameters, and volume overload are some of the risk factors for this disorder. DISCUSSION OSA is a known risk factor complicating the course of arterial hypertension, heart failure, and chronic kidney disease. It is important to note that all of the aforementioned comorbid disorders are associated with volume overload. This explains why patients with OSA and comorbid disorders associated with fluid overload can benefit from treatment with diuretics and drugs modulating the renin-angiotensin-aldosterone system. Additionally, patients with heart failure and high sodium intake are at increased risk for OSA, further supporting the complex interrelationship. CONCLUSIONS Hemodialysis and renal transplantation can markedly improve the severity of OSA in patients with concomitant kidney disease. Finally, there is a potential of a vicious cycle between OSA and fluid overload disorders, whereby OSA can contribute to the pathogenesis of arterial hypertension, heart failure, and chronic kidney disease, which in turn will significantly contribute to the course OSA.
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Affiliation(s)
- Aibek E Mirrakhimov
- Kyrgyz State Medical Academy named after I.K. Akhunbaev, Akhunbaev Street 92, Bishkek 720020, Kyrgyzstan.
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