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Aranda LC, Ribeiro IC, Freitas TO, Degani-Costa LH, Dias DS, De Angelis K, Paixão AO, Brum PC, Oliveira ASB, Vianna LC, Nery LE, Silva BM. Altered locomotor muscle metaboreflex control of ventilation in patients with COPD. J Appl Physiol (1985) 2024; 136:385-398. [PMID: 38174374 DOI: 10.1152/japplphysiol.00560.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 11/20/2023] [Accepted: 12/06/2023] [Indexed: 01/05/2024] Open
Abstract
We investigated the locomotor muscle metaboreflex control of ventilation, circulation, and dyspnea in patients with chronic obstructive pulmonary disease (COPD). Ten patients [forced expiratory volume in 1 second (FEV1; means ± SD) = 43 ± 17% predicted] and nine age- and sex-matched controls underwent 1) cycling exercise followed by postexercise circulatory occlusion (PECO) to activate the metaboreflex or free circulatory flow to inactivate it, 2) cold pressor test to interpret whether any altered reflex response was specific to the metaboreflex arc, and 3) muscle biopsy to explore the metaboreflex arc afferent side. We measured airflow, dyspnea, heart rate, arterial pressure, muscle blood flow, and vascular conductance during reflexes activation. In addition, we measured fiber types, glutathione redox balance, and metaboreceptor-related mRNAs in the vastus lateralis. Metaboreflex activation increased ventilation versus free flow in patients (∼15%, P < 0.020) but not in controls (P > 0.450). In contrast, metaboreflex activation did not change dyspnea in patients (P = 1.000) but increased it in controls (∼100%, P < 0.001). Other metaboreflex-induced responses were similar between groups. Cold receptor activation increased ventilation similarly in both groups (P = 0.46). Patients had greater type II skeletal myocyte percentage (14%, P = 0.010), lower glutathione ratio (-34%, P = 0.015), and lower nerve growth factor (NGF) mRNA expression (-60%, P = 0.031) than controls. Therefore, COPD altered the locomotor muscle metaboreflex control of ventilation. It increased type II myocyte percentage and elicited redox imbalance, potentially producing more muscle metaboreceptor stimuli. Moreover, it decreased NGF expression, suggesting a downregulation of metabolically sensitive muscle afferents.NEW & NOTEWORTHY This study's integrative physiology approach provides evidence for a specific alteration in locomotor muscle metaboreflex control of ventilation in patients with COPD. Furthermore, molecular analyses of a skeletal muscle biopsy suggest that the amount of muscle metaboreceptor stimuli derived from type II skeletal myocytes and redox imbalance overcame a downregulation of metabolically sensitive muscle afferents.
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Affiliation(s)
- Liliane C Aranda
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Department of Physiology, UNIFESP, São Paulo, Brazil
| | - Indyanara C Ribeiro
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Department of Physiology, UNIFESP, São Paulo, Brazil
| | - Tiago O Freitas
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Department of Physiology, UNIFESP, São Paulo, Brazil
| | - Luiza H Degani-Costa
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | | | | | - Ailma O Paixão
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Patricia C Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | | | - Lauro C Vianna
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasilia, Brasilia, Brazil
| | - Luiz E Nery
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Bruno M Silva
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Department of Physiology, UNIFESP, São Paulo, Brazil
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Abstract
The exercise pressor reflex is a feedback mechanism engaged upon stimulation of mechano- and metabosensitive skeletal muscle afferents. Activation of these afferents elicits a reflex increase in heart rate, blood pressure, and ventilation in an intensity-dependent manner. Consequently, the exercise pressor reflex has been postulated to be one of the principal mediators of the cardiorespiratory responses to exercise. In this updated review, we will discuss classical and recent advancements in our understating of the exercise pressor reflex function in both human and animal models. Particular attention will be paid to the afferent mechanisms and pathways involved during its activation, its effects on different target organs, its potential role in the abnormal cardiovascular response to exercise in diseased states, and the impact of age and biological sex on these responses. Finally, we will highlight some unanswered questions in the literature that may inspire future investigations in the field.
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Affiliation(s)
- André L Teixeira
- NeuroV̇ASQ̇, Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, DF, Brasília, Brazil
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Lauro C Vianna
- NeuroV̇ASQ̇, Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, DF, Brasília, Brazil.
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Chen C, Kolbe J, Wilsher ML, De Boer S, Paton JFR, Fisher JP. Cardiorespiratory responses to muscle metaboreflex activation in fibrosing interstitial lung disease. Exp Physiol 2022; 107:527-540. [PMID: 35298060 PMCID: PMC9314965 DOI: 10.1113/ep090252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/10/2022] [Indexed: 11/21/2022]
Abstract
New Findings What is the central question of this study? We determined whether sensory feedback from metabolically sensitive skeletal muscle afferents (metaboreflex) causes a greater ventilatory response and higher dyspnoea ratings in fibrosing interstitial lung disease (FILD). What is the main finding and its importance? Ventilatory responses and dyspnoea ratings during handgrip exercise and metaboreflex isolation were not different in FILD and control groups. Blood pressure and heart rate responses to handgrip were attenuated in FILD but not different to controls during metaboreflex isolation. These findings suggest that the muscle metaboreflex contribution to the respiratory response to exercise is not altered in FILD.
Abstract Exercise limitation and dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD); however, the physiological mechanisms are poorly understood. In other respiratory diseases, there is evidence that an augmented muscle metaboreflex may be implicated. We hypothesized that metaboreflex activation in FILD would result in elevated ventilation and dyspnoea ratings compared to healthy controls, due to augmented muscle metaboreflex. Sixteen FILD patients (three women, 69±14 years; mean±SD) and 16 age‐matched controls (four women, 67±7 years) were recruited. In a randomized cross‐over design, participants completed two min of rhythmic handgrip followed by either (i) two min of post‐exercise circulatory occlusion (PECO trial) to isolate muscle metaboreflex activation, or (ii) rested for four min (Control trial). Minute ventilation (V˙E; pneumotachometer), dyspnoea ratings (0–10 Borg scale), mean arterial pressure (MAP; finger photoplethysmography) and heart rate (HR; electrocardiogram) were measured. V˙E was higher in the FILD group at baseline and exercise increased V˙E similarly in both groups. V˙E remained elevated during PECO, but there was no between‐group difference in the magnitude of this response (ΔV˙E FILD 4.2 ± 2.5 L·min–1 vs. controls 3.6 ± 2.4 L·min–1, P = 0.596). At the end of PECO, dyspnoea ratings in FILD were similar to controls (1.0 ± 1.3 units vs. 0.5 ± 1.1 units). Exercise increased MAP and HR (P < 0.05) in both groups; however, responses were lower in FILD. Collectively, these findings suggest that there is not an augmented effect of the muscle metaboreflex on breathing and dyspnoea in FILD, but haemodynamic responses to handgrip are reduced relative to controls.
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Affiliation(s)
- Charlotte Chen
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - John Kolbe
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand.,Department of Medicine, Faculty of Medical & Health Sciences, University of Auckland, New Zealand.,Respiratory Services, Auckland District Health Board, Auckland, New Zealand
| | - Margaret L Wilsher
- Department of Medicine, Faculty of Medical & Health Sciences, University of Auckland, New Zealand.,Respiratory Services, Auckland District Health Board, Auckland, New Zealand
| | - Sally De Boer
- Respiratory Services, Auckland District Health Board, Auckland, New Zealand
| | - Julian F R Paton
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - James P Fisher
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
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