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Hughes RP, Carlini NA, Fleenor BS, Harber MP. Mitochondrial-targeted antioxidant ingestion acutely blunts VO 2max in physically inactive females. Physiol Rep 2023; 11:e15871. [PMID: 38061764 PMCID: PMC10703545 DOI: 10.14814/phy2.15871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/03/2023] [Accepted: 11/05/2023] [Indexed: 12/17/2023] Open
Abstract
PURPOSE To determine the acute effects of a mitochondrial targeting antioxidant (MitoQ) on the metabolic response during exercise. METHODS Nine (n = 9) physically inactive females (age 47 ± 22 years) performed two trials (Placebo and MitoQ) in a double-blind randomized cross-over design. In both trials, participants performed an exercise protocol consisting of 3-min stages at submaximal workloads followed by a ramp protocol to volitional exhaustion. Participants received either Placebo or MitoQ (80 mg) 1 h prior to exercise. Indirect calorimetry and cardiovascular measurements were collected throughout the duration of the exercise bout. RESULTS Submaximal metabolic and cardiovascular variables were not different between trials (p > 0.05). VO2max was higher (p = 0.03) during Placebo (23.5 ± 5.7 mL kg min-1 ) compared to MitoQ (21.0 ± 6.6 mL kg min-1 ). Maximal ventilation was also higher (p = 0.02) in Placebo (82.4 ± 17.7 L/min) compared to MitoQ (75.0 ± 16.8 L/min). Maximal cardiovascular variables and blood lactate were not different between trials (p > 0.05). CONCLUSION An acute dose of MitoQ blunted VO2max , which was primarily mediated by impairment of ventilatory function. These data suggest that the acute accumulation of exercise-induced mitochondrial reactive oxygen species (mtROS) are necessary for maximal aerobic capacity. Further research is warranted on mtROS-antioxidant cell signaling cascades, and how they relate to mitochondrial function during exercise.
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Affiliation(s)
- Ryan P. Hughes
- Clinical Exercise Physiology, Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
| | - Nicholas A. Carlini
- Clinical Exercise Physiology, Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
| | - Bradley S. Fleenor
- Clinical Exercise Physiology, Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
| | - Matthew P. Harber
- Clinical Exercise Physiology, Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
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Lv R, Liu X, Zhang Y, Dong N, Wang X, He Y, Yue H, Yin Q. Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome. Signal Transduct Target Ther 2023; 8:218. [PMID: 37230968 DOI: 10.1038/s41392-023-01496-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.
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Affiliation(s)
- Renjun Lv
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Xueying Liu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Yue Zhang
- Department of Geriatrics, the 2nd Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
| | - Na Dong
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Xiao Wang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Yao He
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Hongmei Yue
- Department of Pulmonary and Critical Care Medicine, The First Hospital of Lanzhou University, Lanzhou, 730000, China.
| | - Qingqing Yin
- Department of Geriatric Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China.
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Getsy PM, Davis J, Coffee GA, Lewis THJ, Lewis SJ. Hypercapnic signaling influences hypoxic signaling in the control of breathing in C57BL6 mice. J Appl Physiol (1985) 2023; 134:1188-1206. [PMID: 36892890 PMCID: PMC10151047 DOI: 10.1152/japplphysiol.00548.2022] [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: 09/14/2022] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 03/10/2023] Open
Abstract
Interactions between hypoxic and hypercapnic signaling pathways, expressed as ventilatory changes occurring during and following a simultaneous hypoxic-hypercapnic gas challenge (HH-C) have not been determined systematically in mice. This study in unanesthetized male C57BL6 mice addressed the hypothesis that hypoxic (HX) and hypercapnic (HC) signaling events display an array of interactions indicative of coordination by peripheral and central respiratory mechanisms. We evaluated the ventilatory responses elicited by hypoxic (HX-C, 10%, O2, 90% N2), hypercapnic (HC-C, 5% CO2, 21%, O2, 90% N2), and HH-C (10% O2, 5%, CO2, 85% N2) challenges to determine whether ventilatory responses elicited by HH-C were simply additive of responses elicited by HX-C and HC-C, or whether other patterns of interactions existed. Responses elicited by HH-C were additive for tidal volume, minute ventilation and expiratory time, among others. Responses elicited by HH-C were hypoadditive of the HX-C and HC-C responses (i.e., HH-C responses were less than expected by simple addition of HX-C and HC-C responses) for frequency of breathing, inspiratory time and relaxation time, among others. In addition, end-expiratory pause increased during HX-C, but decreased during HC-C and HH-C, therefore showing that HC-C responses influenced the HX-C responses when given simultaneously. Return to room-air responses was additive for tidal volume and minute ventilation, among others, whereas they were hypoadditive for frequency of breathing, inspiratory time, peak inspiratory flow, apneic pause, inspiratory and expiratory drives, and rejection index. These data show that HX-C and HH-C signaling pathways interact with one another in additive and often hypoadditive processes.NEW & NOTEWORTHY We present data showing that the ventilatory responses elicited by a hypoxic gas challenge in male C57BL6 mice are markedly altered by coexposure to hypercapnic gas challenge with hypercapnic responses often dominating the hypoxic responses. These data suggest that hypercapnic signaling processes activated within brainstem regions, such as the retrotrapezoid nuclei, may directly modulate the signaling processes within the nuclei tractus solitarius resulting from hypoxic-induced increase in carotid body chemoreceptor input to these nuclei.
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Affiliation(s)
- Paulina M Getsy
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Jesse Davis
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Gregory A Coffee
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Tristan H J Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Stephen J Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
- Functional Electrical Stimulation Center, Case Western Reserve University, Cleveland, Ohio, United States
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Gupta R, Dyba G, Malgor EA, Campana J, Nehler M, Malgor RD. Morbidity and Long-Term Patient-Reported Outcomes Following Advanced Carotid Body Tumor Resection. Ann Vasc Surg 2023; 92:49-56. [PMID: 36736720 DOI: 10.1016/j.avsg.2023.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 01/05/2023] [Accepted: 01/12/2023] [Indexed: 02/04/2023]
Abstract
BACKGROUND The reported risk of a cranial nerve (CN) injury is up to 1 in 4 patients in large registries of carotid body tumor (CBT) resection. Functional outcome for this population is unknown. METHODS We evaluated consecutive patients who underwent CBT resection from November 2013 through October 2020. Demographics, intraoperative details, complications, and outcomes were recorded from the medical record. Permanent CN nerve injury was defined as deficits lasting >6 months. Frequency statistics, averages, chi-squared test, and multiple logistic regression were completed for primary end points of complications and disease-free survival. Patient-reported outcomes were gathered via telephone survey of patients conducted in September 2021. RESULTS Fifty-one patients presented with CBTs and the following Shamblin classes: I (n = 7; 14%), II (n = 36; 69%), and III (n = 9; 17%). Head and neck oncology and vascular surgery jointly did 52% of CBT resections, including 6 of 9 Shamblin III cases. Eight patients (15.3%, all Shamblin II or III) suffered a total of 12 CN injuries - 8 CN XII (5 temporary and 3 permanent), 3 CN X (all permanent), and 1 CN XI (permanent). Seven of the CN injury subgroup had preoperative embolization and 5 were joint oncology/vascular cases. In addition, 4 separate carotid injuries required repair. Notably, all patients had disease-free survival postoperatively at a mean follow-up of 6 months. Patient-reported outcomes obtained in 70.6% of patients 1 year or more from index operation demonstrated that two-thirds of patients live without any permanent functional deficits, and the majority of those with continued deficits rate the symptoms as daily but mild in severity. CONCLUSIONS In a series of complex CBT patients treated with preoperative embolization capabilities and multidisciplinary surgical approach, disease-free survival was achieved in all patients despite a high rate of iatrogenic CN injuries, most commonly CN XII. Patient-reported outcomes survey results indicate that injuries identified on clinical exam underreport patients' true postoperative CN deficits - especially branches of CN X. This data support the practice of aggressive primary resection of CBTs while providing guidance for expected functional outcomes due to CN injury risk.
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Affiliation(s)
- Ryan Gupta
- Division of Vascular Surgery and Endovascular Therapy, University of Colorado Anschutz School of Medicine, Aurora, CO.
| | - Gregory Dyba
- University of Colorado Anschutz School of Medicine, Aurora, CO
| | - Emily A Malgor
- Division of Vascular Surgery and Endovascular Therapy, University of Colorado Anschutz School of Medicine, Aurora, CO
| | - John Campana
- Division of Head and Neck Surgery, University of Colorado Anschutz School of Medicine, Aurora, CO
| | - Mark Nehler
- Division of Vascular Surgery and Endovascular Therapy, University of Colorado Anschutz School of Medicine, Aurora, CO
| | - Rafael D Malgor
- Division of Vascular Surgery and Endovascular Therapy, University of Colorado Anschutz School of Medicine, Aurora, CO
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Xu F, Zhao L, Zhuang J, Gao X. Peripheral Neuroplasticity of Respiratory Chemoreflexes, Induced by Prenatal Nicotinic Exposure: Implication for SIDS. Respir Physiol Neurobiol 2023; 313:104053. [PMID: 37019251 DOI: 10.1016/j.resp.2023.104053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/23/2023] [Accepted: 04/02/2023] [Indexed: 04/05/2023]
Abstract
Sudden Infant Death Syndrome (SIDS) occurs during sleep in seemingly healthy infants. Maternal cigarette smoking and hypoxemia during sleep are assumed to be the major causal factors. Depressed hypoxic ventilatory response (dHVR) is observed in infants with high risk of SIDS, and apneas (lethal ventilatory arrest) appear during the fatal episode of SIDS. Disturbance of the respiratory center has been proposed to be involved, but the pathogenesis of SIDS is still not fully understood. Peripherally, the carotid body is critical to generate HVR, and bronchopulmonary and superior laryngeal C-fibers (PCFs and SLCFs) are important for triggering central apneas; however, their roles in the pathogenesis of SIDS have not been explored until recently. There are three lines of recently accumulated evidence to show the disorders of peripheral sensory afferent-mediated respiratory chemoreflexes in rat pups with prenatal nicotinic exposure (a SIDS model) in which acute severe hypoxia leads to dHVR followed by lethal apneas. (1) The carotid body-mediated HVR is suppressed with a reduction of the number and sensitivity of glomus cells. (2) PCF-mediated apneic response is largely prolonged via increased PCF density, pulmonary IL-1β and serotonin (5-hydroxytryptamine, 5-HT) release, along with the enhanced expression of TRPV1, NK1R, IL1RI and 5-HT3R in pulmonary C-neurons to strengthen these neural responses to capsaicin, a selective stimulant to C-fibers. (3) SLCF-mediated apnea and capsaicin-induced currents in superior laryngeal C-neurons are augmented by upregulation of TRPV1 expression in these neurons. These results, along with hypoxic sensitization/stimulation of PCFs, gain insight into the mechanisms of prenatal nicotinic exposure-induced peripheral neuroplasticity responsible for dHVR and long-lasting apnea during hypoxia in rat pups. Therefore, in addition to the disturbance in the respiratory center, the disorders of peripheral sensory afferent-mediated chemoreflexes may also be involved in respiratory failure and death denoted in SIDS victims.
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Kamra K, Karpuk N, Adam R, Zucker IH, Schultz HD, Wang HJ. Time-dependent alteration in the chemoreflex post-acute lung injury. Front Physiol 2022; 13:1009607. [PMID: 36338487 PMCID: PMC9630356 DOI: 10.3389/fphys.2022.1009607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/04/2022] [Indexed: 11/30/2022] Open
Abstract
Acute lung injury (ALI) induces inflammation that disrupts the normal alveolar-capillary endothelial barrier which impairs gas exchange to induce hypoxemia that reflexively increases respiration. The neural mechanisms underlying the respiratory dysfunction during ALI are not fully understood. The purpose of this study was to investigate the role of the chemoreflex in mediating abnormal ventilation during acute (early) and recovery (late) stages of ALI. We hypothesized that the increase in respiratory rate (fR) during post-ALI is mediated by a sensitized chemoreflex. ALI was induced in male Sprague-Dawley rats using a single intra-tracheal injection of bleomycin (Bleo: low-dose = 1.25 mg/Kg or high-dose = 2.5 mg/Kg) (day 1) and respiratory variables- fR, Vt (Tidal Volume), and VE (Minute Ventilation) in response to 10% hypoxia (10% O2, 0% CO2) and 5% hypercapnia/21% normoxia (21% O2, 5% CO2) were measured weekly from W0-W4 using whole-body plethysmography (WBP). Our data indicate sensitization (∆fR = 93 ± 31 bpm, p < 0.0001) of the chemoreflex at W1 post-ALI in response to hypoxic/hypercapnic gas challenge in the low-dose bleo (moderate ALI) group and a blunted chemoreflex (∆fR = -0.97 ± 42 bpm, p < 0.0001) at W1 post-ALI in the high-dose bleo (severe ALI) group. During recovery from ALI, at W3-W4, both low-dose and high-dose groups exhibited a sensitized chemoreflex in response to hypoxia and normoxic-hypercapnia. We then hypothesized that the blunted chemoreflex at W1 post-ALI in the high-dose bleo group could be due to near maximal tonic activation of chemoreceptors, called the "ceiling effect". To test this possibility, 90% hyperoxia (90% O2, 0% CO2) was given to bleo treated rats to inhibit the chemoreflex. Our results showed no changes in fR, suggesting absence of the tonic chemoreflex activation in response to hypoxia at W1 post-ALI. These data suggest that during the acute stage of moderate (low-dose bleo) and severe (high-dose bleo) ALI, chemoreflex activity trends to be slightly sensitized and blunted, respectively while it becomes significantly sensitized during the recovery stage. Future studies are required to examine the molecular/cellular mechanisms underlying the time-course changes in chemoreflex sensitivity post-ALI.
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Affiliation(s)
- Kajal Kamra
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States,Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Nikolay Karpuk
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Ryan Adam
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Irving H. Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Harold D. Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Han-Jun Wang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States,Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, United States,*Correspondence: Han-Jun Wang,
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Dakik H, El Dor M, Bourgeais J, Kouzi F, Herault O, Gouilleux F, Zibara K, Mazurier F. Diphenyleneiodonium Triggers Cell Death of Acute Myeloid Leukemia Cells by Blocking the Mitochondrial Respiratory Chain, and Synergizes with Cytarabine. Cancers (Basel) 2022; 14:cancers14102485. [PMID: 35626090 PMCID: PMC9140039 DOI: 10.3390/cancers14102485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 12/19/2022] Open
Abstract
Simple Summary Acute myeloid leukemia (AML) is an aggressive heterogeneous cancer of the blood, of which 70% of cases develop relapse. Relapse is mainly due to chemoresistant leukemic cells (LCs) that are characterized by high mitochondrial oxidative phosphorylation (OxPhos) status, i.e., cells that are dependent on the mitochondrial respiratory chain (MRC) function. The aim of our study was to determine whether diphenyleneiodonium (DPI)—known as a potent inhibitor of flavoproteins—could be used to target AML cells. Herein, we demonstrate that DPI disrupts the mitochondrial function of AML cell lines. Interestingly, we found that cells with high OxPhos are more sensitive to the apoptotic effects of DPI. Moreover, we showed that DPI sensitizes AML cell lines to cytarabine (Ara-C) treatment, suggesting that MRC inhibitors could be employed to target LCs that are resistant to this chemotherapeutic agent. Abstract Acute myeloid leukemia (AML) is characterized by the accumulation of undifferentiated blast cells in the bone marrow and blood. In most cases of AML, relapse frequently occurs due to resistance to chemotherapy. Compelling research results indicate that drug resistance in cancer cells is highly dependent on the intracellular levels of reactive oxygen species (ROS). Modulating ROS levels is therefore a valuable strategy to overcome the chemotherapy resistance of leukemic cells. In this study, we evaluated the efficiency of diphenyleneiodonium (DPI)—a well-known inhibitor of ROS production—in targeting AML cells. Results showed that although inhibiting cytoplasmic ROS production, DPI also triggered an increase in the mitochondrial ROS levels, caused by the disruption of the mitochondrial respiratory chain. We also demonstrated that DPI blocks mitochondrial oxidative phosphorylation (OxPhos) in a dose-dependent manner, and that AML cells with high OxPhos status are highly sensitive to treatment with DPI, which synergizes with the chemotherapeutic agent cytarabine (Ara-C). Thus, our results suggest that targeting mitochondrial function with DPI might be exploited to target AML cells with high OxPhos status.
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Affiliation(s)
- Hassan Dakik
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
| | - Maya El Dor
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
| | - Jérôme Bourgeais
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
- Department of Biological Hematology, Tours University Hospital, F-37000 Tours, France
| | - Farah Kouzi
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
- Biology Department, Faculty of Sciences, Lebanese University, Beirut 90656, Lebanon
| | - Olivier Herault
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
- Department of Biological Hematology, Tours University Hospital, F-37000 Tours, France
| | - Fabrice Gouilleux
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
| | - Kazem Zibara
- Biology Department, Faculty of Sciences, Lebanese University, Beirut 90656, Lebanon
- ER045, PRASE, Beirut 6573/14, Lebanon
- Correspondence: (K.Z.); (F.M.)
| | - Frédéric Mazurier
- EA7501 GICC/CNRS ERL7001 LNOx, University of Tours, F-37032 Tours, France; (H.D.); (M.E.D.); (J.B.); (F.K.); (O.H.); (F.G.)
- Correspondence: (K.Z.); (F.M.)
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Abstract
ABSTRACT
Hypoxia is one of the strongest environmental drivers of cellular and physiological adaptation. Although most mammals are largely intolerant of hypoxia, some specialized species have evolved mitigative strategies to tolerate hypoxic niches. Among the most hypoxia-tolerant mammals are naked mole-rats (Heterocephalus glaber), a eusocial species of subterranean rodent native to eastern Africa. In hypoxia, naked mole-rats maintain consciousness and remain active despite a robust and rapid suppression of metabolic rate, which is mediated by numerous behavioural, physiological and cellular strategies. Conversely, hypoxia-intolerant mammals and most other hypoxia-tolerant mammals cannot achieve the same degree of metabolic savings while staying active in hypoxia and must also increase oxygen supply to tissues, and/or enter torpor. Intriguingly, recent studies suggest that naked mole-rats share many cellular strategies with non-mammalian vertebrate champions of anoxia tolerance, including the use of alternative metabolic end-products and potent pH buffering mechanisms to mitigate cellular acidification due to upregulation of anaerobic metabolic pathways, rapid mitochondrial remodelling to favour increased respiratory efficiency, and systemic shifts in energy prioritization to maintain brain function over that of other tissues. Herein, I discuss what is known regarding adaptations of naked mole-rats to a hypoxic lifestyle, and contrast strategies employed by this species to those of hypoxia-intolerant mammals, closely related African mole-rats, other well-studied hypoxia-tolerant mammals, and non-mammalian vertebrate champions of anoxia tolerance. I also discuss the neotenic theory of hypoxia tolerance – a leading theory that may explain the evolutionary origins of hypoxia tolerance in mammals – and highlight promising but underexplored avenues of hypoxia-related research in this fascinating model organism.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 9A7. University of Ottawa, Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
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Ventilatory responses during and following hypercapnic gas challenge are impaired in male but not female endothelial NOS knock-out mice. Sci Rep 2021; 11:20557. [PMID: 34663876 PMCID: PMC8523677 DOI: 10.1038/s41598-021-99922-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 09/24/2021] [Indexed: 11/28/2022] Open
Abstract
The roles of endothelial nitric oxide synthase (eNOS) in the ventilatory responses during and after a hypercapnic gas challenge (HCC, 5% CO2, 21% O2, 74% N2) were assessed in freely-moving female and male wild-type (WT) C57BL6 mice and eNOS knock-out (eNOS-/-) mice of C57BL6 background using whole body plethysmography. HCC elicited an array of ventilatory responses that were similar in male and female WT mice, such as increases in breathing frequency (with falls in inspiratory and expiratory times), and increases in tidal volume, minute ventilation, peak inspiratory and expiratory flows, and inspiratory and expiratory drives. eNOS-/- male mice had smaller increases in minute ventilation, peak inspiratory flow and inspiratory drive, and smaller decreases in inspiratory time than WT males. Ventilatory responses in female eNOS-/- mice were similar to those in female WT mice. The ventilatory excitatory phase upon return to room-air was similar in both male and female WT mice. However, the post-HCC increases in frequency of breathing (with decreases in inspiratory times), and increases in tidal volume, minute ventilation, inspiratory drive (i.e., tidal volume/inspiratory time) and expiratory drive (i.e., tidal volume/expiratory time), and peak inspiratory and expiratory flows in male eNOS-/- mice were smaller than in male WT mice. In contrast, the post-HCC responses in female eNOS-/- mice were equal to those of the female WT mice. These findings provide the first evidence that the loss of eNOS affects the ventilatory responses during and after HCC in male C57BL6 mice, whereas female C57BL6 mice can compensate for the loss of eNOS, at least in respect to triggering ventilatory responses to HCC.
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Getsy PM, Sundararajan S, May WJ, von Schill GC, McLaughlin DK, Palmer LA, Lewis SJ. Short-term facilitation of breathing upon cessation of hypoxic challenge is impaired in male but not female endothelial NOS knock-out mice. Sci Rep 2021; 11:18346. [PMID: 34526532 PMCID: PMC8443732 DOI: 10.1038/s41598-021-97322-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 08/09/2021] [Indexed: 02/08/2023] Open
Abstract
Decreases in arterial blood oxygen stimulate increases in minute ventilation via activation of peripheral and central respiratory structures. This study evaluates the role of endothelial nitric oxide synthase (eNOS) in the expression of the ventilatory responses during and following a hypoxic gas challenge (HXC, 10% O2, 90% N2) in freely moving male and female wild-type (WT) C57BL6 and eNOS knock-out (eNOS-/-) mice. Exposure to HXC caused an array of responses (of similar magnitude and duration) in both male and female WT mice such as, rapid increases in frequency of breathing, tidal volume, minute ventilation and peak inspiratory and expiratory flows, that were subject to pronounced roll-off. The responses to HXC in male eNOS-/- mice were similar to male WT mice. In contrast, several of the ventilatory responses in female eNOS-/- mice (e.g., frequency of breathing, and expiratory drive) were greater compared to female WT mice. Upon return to room-air, male and female WT mice showed similar excitatory ventilatory responses (i.e., short-term potentiation phase). These responses were markedly reduced in male eNOS-/- mice, whereas female eNOS-/- mice displayed robust post-HXC responses that were similar to those in female WT mice. Our data demonstrates that eNOS plays important roles in (1) ventilatory responses to HXC in female compared to male C57BL6 mice; and (2) expression of post-HXC responses in male, but not female C57BL6 mice. These data support existing evidence that sex, and the functional roles of specific proteins (e.g., eNOS) have profound influences on ventilatory processes, including the responses to HXC.
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Affiliation(s)
- Paulina M. Getsy
- grid.67105.350000 0001 2164 3847Department of Pediatrics, Biomedical Research Building BRB 319, Case Western Reserve University, 10900 Euclid Avenue Mail Stop 1714, Cleveland, OH 44106-1714 USA ,grid.67105.350000 0001 2164 3847Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH USA
| | - Sripriya Sundararajan
- grid.27755.320000 0000 9136 933XPediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.411024.20000 0001 2175 4264Present Address: Division of Neonatology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Walter J. May
- grid.27755.320000 0000 9136 933XPediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Graham C. von Schill
- grid.27755.320000 0000 9136 933XPediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Dylan K. McLaughlin
- grid.27755.320000 0000 9136 933XPediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Lisa A. Palmer
- grid.27755.320000 0000 9136 933XPediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Stephen J. Lewis
- grid.67105.350000 0001 2164 3847Department of Pediatrics, Biomedical Research Building BRB 319, Case Western Reserve University, 10900 Euclid Avenue Mail Stop 1714, Cleveland, OH 44106-1714 USA ,grid.67105.350000 0001 2164 3847Department of Pharmacology, Case Western Reserve University, Cleveland, OH USA ,grid.67105.350000 0001 2164 3847Functional Electrical Stimulation Center, Case Western Reserve University, Cleveland, OH USA
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11
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Sharpe E, Lacombe A, Sadowski A, Phipps J, Heer R, Rajurkar S, Hanes D, Jindal RD, Bradley R. Investigating components of pranayama for effects on heart rate variability. J Psychosom Res 2021; 148:110569. [PMID: 34271528 PMCID: PMC8568305 DOI: 10.1016/j.jpsychores.2021.110569] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Traditional Indian breath control practices of Pranayama have been shown to increase indices of heart rate variability (HRV) that are generally held to reflect parasympathetic nervous system (PNS) tone. To our knowledge, individual components of pranayama have not been separately evaluated for impact on HRV. The objective of this study was to isolate five components of a pranayama practice and evaluate their impact on HRV. METHODS In a crossover clinical trial, 46 healthy adults were allocated to complete five activities in random order, over five separate visits: 1) sitting quietly; 2) self-paced deep breathing; 3) externally-paced deep breathing; 4) self-paced Sheetali/Sheetkari pranayama; and 5) externally paced Sheetali/Sheetkari pranayama RESULTS: Our final sample included 25 participants. There was a significant increase in a time-domain index of HRV, the root mean square successive differences between RR intervals (RMSSD), during the five interventions. The change in logRMSSD ranged from 0.2 to 0.5 (p < .01 in all conditions by paired t-test). Greater increases were evident during externally-paced breathing than during self-paced breathing (mean pre-during logRMSSD change of 0.50 vs. 0.36, p = .02) or sitting quietly (mean, 0.17 ms; p = .005 and 0.02 when comparing Activities 3 and 5 to Activity 1 by random intercept model with Tukey correction for multiple comparisons). Lastly, pre-during increase in RMSSD was greater for Sheetali/Sheetkari vs. deep breathing, when controlling for respiration rate, though not significantly different (p = .07 in random intercept model) CONCLUSIONS: RMSSD increased with paced breathing, deep breathing, and Sheetali/Sheetkari pranayama, reinforcing evidence of a physiologic mechanism of pranayama. TRIAL REGISTRATION NCT03280589 https://www.clinicaltrials.gov/ct2/show/NCT03280589?term=sheetali&draw=2&rank=1.
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Affiliation(s)
- Erica Sharpe
- National University of Natural Medicine, Portland, OR, United States of America; State University of New York at Canton, Canton, NY, United States of America.
| | - Alison Lacombe
- National University of Natural Medicine, Portland, OR,United States Department of Agriculture, Produce Safety Microbiology Research Unit, Albany, CA
| | - Adam Sadowski
- National University of Natural Medicine, Portland, OR, United States of America.
| | - John Phipps
- National University of Natural Medicine, Portland, OR, United States of America.
| | - Ryan Heer
- National University of Natural Medicine, Portland, OR
| | - Savita Rajurkar
- National University of Natural Medicine, Portland, OR, United States of America.
| | - Douglas Hanes
- National University of Natural Medicine, Portland, OR, United States of America.
| | - Ripu D Jindal
- Birmingham VA Medical Center, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Ryan Bradley
- National University of Natural Medicine, Portland, OR, United States of America; University of California, San Diego, La Jolla, CA, United States of America; Australian Research Centre in Complementary and Integrative Medicine, Faculty of Health, University of Technology Sydney, Ultimo, NSW, Australia.
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12
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Getsy PM, Sundararajan S, Lewis SJ. Carotid sinus nerve transection abolishes the facilitation of breathing that occurs upon cessation of a hypercapnic gas challenge in male mice. J Appl Physiol (1985) 2021; 131:821-835. [PMID: 34236243 DOI: 10.1152/japplphysiol.01031.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Arterial pCO2 elevations increase minute ventilation via activation of chemosensors within the carotid body (CB) and brainstem. Although the roles of CB chemoafferents in the hypercapnic (HC) ventilatory response have been investigated, there are no studies reporting the role of these chemoafferents in the ventilatory responses to a HC challenge or the responses that occur upon return to room air, in freely moving mice. This study found that an HC challenge (5% CO2, 21% O2, 74% N2 for 15 min) elicited an array of responses, including increases in frequency of breathing (accompanied by decreases in inspiratory and expiratory times), and increases in tidal volume, minute ventilation, peak inspiratory and expiratory flows, and inspiratory and expiratory drives in sham-operated (SHAM) adult male C57BL6 mice, and that return to room air elicited a brief excitatory phase followed by gradual recovery of all parameters toward baseline values over a 15-min period. The array of ventilatory responses to the HC challenge in mice with bilateral carotid sinus nerve transection (CSNX) performed 7 days previously occurred more slowly but reached similar maxima as SHAM mice. A major finding was responses upon return to room air were dramatically lower in CSNX mice than SHAM mice, and the parameters returned to baseline values within 1-2 min in CSNX mice, whereas it took much longer in SHAM mice. These findings are the first evidence that CB chemoafferents play a key role in initiating the ventilatory responses to HC challenge in C57BL6 mice and are essential for the expression of post-HC ventilatory responses.NEW & NOTEWORTHY This study presents the first evidence that carotid body chemoafferents play a key role in initiating the ventilatory responses, such as increases in frequency of breathing, tidal volume, and minute ventilation that occur in response to a hypercapnic gas challenge in freely moving C57BL6 mice. Our study also demonstrates for the first time that these chemoafferents are essential for the expression of the ventilatory responses that occur upon return to room air in these mice.
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Affiliation(s)
- Paulina M Getsy
- Department of Pediatrics, Case Western University, Cleveland, Ohio
| | - Sripriya Sundararajan
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Stephen J Lewis
- Department of Pediatrics, Case Western University, Cleveland, Ohio.,Department of Pharmacology, Case Western University, Cleveland, Ohio
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13
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Carr JMJR, Caldwell HG, Ainslie PN. Cerebral blood flow, cerebrovascular reactivity and their influence on ventilatory sensitivity. Exp Physiol 2021; 106:1425-1448. [PMID: 33932955 DOI: 10.1113/ep089446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 04/26/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? Cerebrovascular reactivity to CO2 , which is a principal factor in determining ventilatory responses to CO2 through the role reactivity plays in determining cerebral extra- and intracellular pH. What advances does it highlight? Recent animal evidence suggests central chemoreceptor vasculature may demonstrate regionally heterogeneous cerebrovascular reactivity to CO2 , potentially as a protective mechanism against excessive CO2 washout from the central chemoreceptors, thereby allowing ventilation to reflect the systemic acid-base balance needs (respiratory changes in P aC O 2 ) rather than solely the cerebral needs. Ventilation per se does not influence cerebrovascular reactivity independent of changes in P aC O 2 . ABSTRACT Alveolar ventilation and cerebral blood flow are both predominantly regulated by arterial blood gases, especially arterial P C O 2 , and so are intricately entwined. In this review, the fundamental mechanisms underlying cerebrovascular reactivity and central chemoreceptor control of breathing are covered. We discuss the interaction of cerebral blood flow and its reactivity with the control of ventilation and ventilatory responsiveness to changes in P C O 2 , as well as the lack of influence of ventilation itself on cerebrovascular reactivity. We briefly summarize the effects of arterial hypoxaemia on the relationship between ventilatory and cerebrovascular response to both P C O 2 and P O 2 . We then highlight key methodological considerations regarding the interaction of reactivity and ventilatory sensitivity, including the following: regional heterogeneity of cerebrovascular reactivity; a pharmacological approach for the reduction of cerebral blood flow; reactivity assessment techniques; the influence of mean arterial blood pressure; and sex-related differences. Finally, we discuss ventilatory and cerebrovascular control in the context of high altitude and congestive heart failure. Future research directions and pertinent questions of interest are highlighted throughout.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, British Columbia, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, British Columbia, Canada
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14
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Altamirano AE, Wilson CG. An overview of developmental dysregulation of autonomic control in infants. Birth Defects Res 2021; 113:864-871. [PMID: 33421331 DOI: 10.1002/bdr2.1855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 11/30/2020] [Indexed: 11/10/2022]
Abstract
In this short review, we provide an overview of developmental disorders causing autonomic nervous system dysregulation. We briefly discuss perinatal conditions that adversely impact developmental outcomes including apnea of prematurity, sudden infant death syndrome, and Rett syndrome. We provide a brief clinical description, an overview of known or hypothesized mechanisms for the disorder, and current standard of practice for treatment of each condition. Additionally, we consider preventative measures and complications of these disorders to provide further insight into the pathogenesis of specific autonomic dysregulation in neonates. The goal of this short review is to provide an updated understanding of the impact of autonomic dysregulation on development of brainstem circuits and to briefly highlight promising future treatment options and controversies.
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Affiliation(s)
- Adulzir E Altamirano
- Center for Health Disparities, Loma Linda University, Loma Linda, California, USA.,Lawrence D. Longo, M.D. Center for Perinatal Biology, Loma Linda, California, USA
| | - Christopher G Wilson
- Lawrence D. Longo, M.D. Center for Perinatal Biology, Loma Linda, California, USA
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15
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Getsy PM, Coffee GA, Lewis SJ. The Role of Carotid Sinus Nerve Input in the Hypoxic-Hypercapnic Ventilatory Response in Juvenile Rats. Front Physiol 2020; 11:613786. [PMID: 33391030 PMCID: PMC7773764 DOI: 10.3389/fphys.2020.613786] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 11/25/2020] [Indexed: 01/17/2023] Open
Abstract
In juvenile rats, the carotid body (CB) is the primary sensor of oxygen (O2) and a secondary sensor of carbon dioxide (CO2) in the blood. The CB communicates to the respiratory pattern generator via the carotid sinus nerve, which terminates within the commissural nucleus tractus solitarius (cNTS). While this is not the only peripheral chemosensory pathway in juvenile rodents, we hypothesize that it has a unique role in determining the interaction between O2 and CO2, and consequently, the response to hypoxic-hypercapnic gas challenges. The objectives of this study were to determine (1) the ventilatory responses to a poikilocapnic hypoxic (HX) gas challenge, a hypercapnic (HC) gas challenge or a hypoxic-hypercapnic (HH) gas challenge in juvenile rats; and (2) the roles of CSN chemoafferents in the interactions between HX and HC signaling in these rats. Studies were performed on conscious, freely moving juvenile (P25) male Sprague Dawley rats that underwent sham-surgery (SHAM) or bilateral transection of the carotid sinus nerves (CSNX) 4 days previously. Rats were placed in whole-body plethysmographs to record ventilatory parameters (frequency of breathing, tidal volume and minute ventilation). After acclimatization, they were exposed to HX (10% O2, 90% N2), HC (5% CO2, 21% O2, 74% N2) or HH (5% CO2, 10% O2, 85% N2) gas challenges for 5 min, followed by 15 min of room-air. The major findings were: (1) the HX, HC and HH challenges elicited robust ventilatory responses in SHAM rats; (2) ventilatory responses elicited by HX alone and HC alone were generally additive in SHAM rats; (3) the ventilatory responses to HX, HC and HH were markedly attenuated in CSNX rats compared to SHAM rats; and (4) ventilatory responses elicited by HX alone and HC alone were not additive in CSNX rats. Although the rats responded to HX after CSNX, CB chemoafferent input was necessary for the response to HH challenge. Thus, secondary peripheral chemoreceptors do not compensate for the loss of chemoreceptor input from the CB in juvenile rats.
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Affiliation(s)
- Paulina M Getsy
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Gregory A Coffee
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen J Lewis
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States
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16
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Evans AM, Hardie DG. AMPK and the Need to Breathe and Feed: What's the Matter with Oxygen? Int J Mol Sci 2020; 21:ijms21103518. [PMID: 32429235 PMCID: PMC7279029 DOI: 10.3390/ijms21103518] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022] Open
Abstract
We live and to do so we must breathe and eat, so are we a combination of what we eat and breathe? Here, we will consider this question, and the role in this respect of the AMP-activated protein kinase (AMPK). Emerging evidence suggests that AMPK facilitates central and peripheral reflexes that coordinate breathing and oxygen supply, and contributes to the central regulation of feeding and food choice. We propose, therefore, that oxygen supply to the body is aligned with not only the quantity we eat, but also nutrient-based diet selection, and that the cell-specific expression pattern of AMPK subunit isoforms is critical to appropriate system alignment in this respect. Currently available information on how oxygen supply may be aligned with feeding and food choice, or vice versa, through our motivation to breathe and select particular nutrients is sparse, fragmented and lacks any integrated understanding. By addressing this, we aim to provide the foundations for a clinical perspective that reveals untapped potential, by highlighting how aberrant cell-specific changes in the expression of AMPK subunit isoforms could give rise, in part, to known associations between metabolic disease, such as obesity and type 2 diabetes, sleep-disordered breathing, pulmonary hypertension and acute respiratory distress syndrome.
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Affiliation(s)
- A. Mark Evans
- Centre for Discovery Brain Sciences and Cardiovascular Science, Edinburgh Medical School, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
- Correspondence:
| | - D. Grahame Hardie
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK;
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17
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Steady-state cerebral blood flow regulation at altitude: interaction between oxygen and carbon dioxide. Eur J Appl Physiol 2019; 119:2529-2544. [DOI: 10.1007/s00421-019-04206-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 08/06/2019] [Indexed: 02/07/2023]
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18
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AMPK breathing and oxygen supply. Respir Physiol Neurobiol 2019; 265:112-120. [DOI: 10.1016/j.resp.2018.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/06/2018] [Accepted: 08/31/2018] [Indexed: 01/28/2023]
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19
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Velotta JP, Cheviron ZA. Remodeling Ancestral Phenotypic Plasticity in Local Adaptation: A New Framework to Explore the Role of Genetic Compensation in the Evolution of Homeostasis. Integr Comp Biol 2019; 58:1098-1110. [PMID: 30272147 DOI: 10.1093/icb/icy117] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phenotypic plasticity is not universally adaptive. In certain cases, plasticity can result in phenotypic shifts that reduce fitness relative to the un-induced state. A common cause of such maladaptive plasticity is the co-option of ancestral developmental and physiological response systems to meet novel challenges. Because these systems evolved to meet specific challenges in an ancestral environment (e.g., localized and transient hypoxia), their co-option to meet a similar, but novel, stressor (e.g., reductions in ambient pO2 at high elevation) can lead to misdirected responses that reduce fitness. In such cases, natural selection should act to remodel phenotypic plasticity to suppress the expression of these maladaptive responses. Because these maladaptive responses reduce the fitness of colonizers in new environments, this remodeling of ancestral plasticity may be among the earliest steps in adaptive walks toward new local optima. Genetic compensation has been proposed as a general form of adaptive evolution that leads to the suppression of maladaptive plasticity to restore the ancestral trait value in the face of novel stimuli. Given their central role in the regulation of basic physiological functions, we argue that genetic compensation may often be achieved by modifications of homeostatic regulatory systems. We further suggest that genetic compensation to modify homeostatic systems can be achieved by two alternative strategies that differ in their mechanistic underpinnings; to our knowledge, these strategies have not been formally recognized by previous workers. We then consider how the mechanistic details of these alternative strategies may constrain their evolution. These considerations lead us to argue that genetic compensation is most likely to evolve by compensatory physiological changes that safeguard internal homeostatic conditions to prevent the expression of maladaptive portions of conserved reaction norms, rather than direct evolution of plasticity itself. Finally, we outline a simple experimental framework to test this hypothesis. Our goal is to stimulate research aimed at providing a deeper mechanistic understanding of whether and how phenotypic plasticity can be remodeled following environmental shifts that render ancestral responses maladaptive, an issue with increasing importance in our current era of rapid environmental change.
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Affiliation(s)
- Jonathan P Velotta
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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20
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Carotid chemoreceptor denervation does not impair hypoxia-induced thermal downregulation but vitiates recovery from a hypothermic and hypometabolic state in mice. Sci Rep 2019; 9:5132. [PMID: 30914789 PMCID: PMC6435667 DOI: 10.1038/s41598-019-41546-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/05/2019] [Indexed: 01/03/2023] Open
Abstract
Induction of hypothermia and consequent hypometabolism by pharmacological downmodulation of the internal thermostat could be protective in various medical situations such as ischemia/reperfusion. Systemic hypoxia is a trigger of thermostat downregulation in some mammals, which is sensed though carotid chemoreceptors (carotid bodies, CBs). Using non-invasive thermographic imaging in mice, we demonstrated that surgical bilateral CB denervation does not hamper hypoxia-induced hypothermia. However, the recovery from a protective and reversible hypothermic state after restoration to normoxic conditions was impaired in CB-resected mice versus control animals. Therefore, the carotid chemoreceptors play an important role in the central regulation of hypoxia-driven hypothermia in mice, but only in the rewarming phase.
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21
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Sun M, Jiang F, Cen B, Wen J, Zhou Y, Wu Z. Respiratory burst oxidase homologue-dependent H 2 O 2 and chloroplast H 2 O 2 are essential for the maintenance of acquired thermotolerance during recovery after acclimation. PLANT, CELL & ENVIRONMENT 2018; 41:2373-2389. [PMID: 29851102 DOI: 10.1111/pce.13351] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/21/2018] [Accepted: 05/21/2018] [Indexed: 05/22/2023]
Abstract
Thermotolerance is improved by heat stress (HS) acclimation, and the thermotolerance level is "remembered" by plants. However, the underlying signalling mechanisms remain largely unknown. Here, we showed NADPH oxidase-mediated H2 O2 (NADPH-H2 O2 ), and chloroplast-H2 O2 promoted the sustained expression of HS-responsive genes and programmed cell death (PCD) genes, respectively, during recovery after HS acclimation. When spraying the NADPH oxidase inhibitor, diphenylene iodonium, after HS acclimation, the NADPH-H2 O2 level significantly decreased, resulting in a decrease in the expression of HS-responsive genes and the loss of maintenance of acquired thermotolerance (MAT). In contrast, compared with HS acclimation, NADPH-H2 O2 declined but chloroplast-H2 O2 further enhanced during recovery after HS over-acclimation, resulting in the reduced expression of HS-responsive genes and substantial production of PCD. Notably, the further inhibition of NADPH-H2 O2 after HS over-acclimation also inhibited chloroplast-H2 O2 , alleviating the severe PCD and surpassing the MAT of HS over-acclimation treatment. Due to the change in subcellular H2 O2 after HS acclimation, the tomato seedlings maintained a constant H2 O2 level during recovery, resulting in stable and lower total H2 O2 levels during a tester HS challenge conducted after recovery. We conclude that tomato seedlings increase their MAT by enhancing NADPH-H2 O2 content and controlling chloroplast-H2 O2 production during recovery, which enhances the expression of HS-responsive genes and balances PCD levels, respectively.
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Affiliation(s)
- Mintao Sun
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, Nanjing, China
| | - Fangling Jiang
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, Nanjing, China
| | - Benjian Cen
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, Nanjing, China
| | - Junqin Wen
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, Nanjing, China
| | - Yanzhao Zhou
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, Nanjing, China
| | - Zhen Wu
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, Nanjing, China
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22
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Chakravarthy S, Balasubramani PP, Mandali A, Jahanshahi M, Moustafa AA. The many facets of dopamine: Toward an integrative theory of the role of dopamine in managing the body's energy resources. Physiol Behav 2018; 195:128-141. [DOI: 10.1016/j.physbeh.2018.06.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/07/2018] [Accepted: 06/20/2018] [Indexed: 02/07/2023]
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23
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Rajani V, Zhang Y, Jalubula V, Rancic V, SheikhBahaei S, Zwicker JD, Pagliardini S, Dickson CT, Ballanyi K, Kasparov S, Gourine AV, Funk GD. Release of ATP by pre-Bötzinger complex astrocytes contributes to the hypoxic ventilatory response via a Ca 2+ -dependent P2Y 1 receptor mechanism. J Physiol 2018; 596:3245-3269. [PMID: 28678385 PMCID: PMC6068109 DOI: 10.1113/jp274727] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 06/27/2017] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS The ventilatory response to reduced oxygen (hypoxia) is biphasic, comprising an initial increase in ventilation followed by a secondary depression. Our findings indicate that, during hypoxia, astrocytes in the pre-Bötzinger complex (preBötC), a critical site of inspiratory rhythm generation, release a gliotransmitter that acts via P2Y1 receptors to stimulate ventilation and reduce the secondary depression. In vitro analyses reveal that ATP excitation of the preBötC involves P2Y1 receptor-mediated release of Ca2+ from intracellular stores. By identifying a role for gliotransmission and the sites, P2 receptor subtype, and signalling mechanisms via which ATP modulates breathing during hypoxia, these data advance our understanding of the mechanisms underlying the hypoxic ventilatory response and highlight the significance of purinergic signalling and gliotransmission in homeostatic control. Clinically, these findings are relevant to conditions in which hypoxia and respiratory depression are implicated, including apnoea of prematurity, sleep disordered breathing and congestive heart failure. ABSTRACT The hypoxic ventilatory response (HVR) is biphasic, consisting of a phase I increase in ventilation followed by a secondary depression (to a steady-state phase II) that can be life-threatening in premature infants who suffer from frequent apnoeas and respiratory depression. ATP released in the ventrolateral medulla oblongata during hypoxia attenuates the secondary depression. We explored a working hypothesis that vesicular release of ATP by astrocytes in the pre-Bötzinger Complex (preBötC) inspiratory rhythm-generating network acts via P2Y1 receptors to mediate this effect. Blockade of vesicular exocytosis in preBötC astrocytes bilaterally (using an adenoviral vector to specifically express tetanus toxin light chain in astrocytes) reduced the HVR in anaesthetized rats, indicating that exocytotic release of a gliotransmitter within the preBötC contributes to the hypoxia-induced increases in ventilation. Unilateral blockade of P2Y1 receptors in the preBötC via local antagonist injection enhanced the secondary respiratory depression, suggesting that a significant component of the phase II increase in ventilation is mediated by ATP acting at P2Y1 receptors. In vitro responses of the preBötC inspiratory network, preBötC inspiratory neurons and cultured preBötC glia to purinergic agents demonstrated that the P2Y1 receptor-mediated increase in fictive inspiratory frequency involves Ca2+ recruitment from intracellular stores leading to increases in intracellular Ca2+ ([Ca2+ ]i ) in inspiratory neurons and glia. These data suggest that ATP is released by preBötC astrocytes during hypoxia and acts via P2Y1 receptors on inspiratory neurons (and/or glia) to evoke Ca2+ release from intracellular stores and an increase in ventilation that counteracts the hypoxic respiratory depression.
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Affiliation(s)
- Vishaal Rajani
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
- Present address: Neurosciences & Mental Health, Peter Gilgan Centre for Research and Learning (PGCRL)The Hospital for Sick ChildrenTorontoOntarioCanada
| | - Yong Zhang
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Venkatesh Jalubula
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Vladimir Rancic
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Shahriar SheikhBahaei
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS)National Institutes of Health (NIH)BethesdaMDUSA
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonUK
| | - Jennifer D. Zwicker
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Silvia Pagliardini
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Clayton T. Dickson
- Department of Psychology, Neuroscience and Mental Health Institute (NMHI)Faculty of ScienceEdmontonAlbertaCanada
| | - Klaus Ballanyi
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Sergey Kasparov
- Department of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Alexander V. Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonUK
| | - Gregory D. Funk
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
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24
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Oyarce MP, Iturriaga R. Contribution of Oxidative Stress and Inflammation to the Neurogenic Hypertension Induced by Intermittent Hypoxia. Front Physiol 2018; 9:893. [PMID: 30050461 PMCID: PMC6050421 DOI: 10.3389/fphys.2018.00893] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/21/2018] [Indexed: 12/11/2022] Open
Abstract
Chronic intermittent hypoxia (CIH), the hallmark of obstructive sleep apnea, is the main risk factor to develop systemic hypertension. Oxidative stress, inflammation, and sympathetic overflow have been proposed as possible mechanisms underlying the CIH-induced hypertension. CIH potentiates the carotid body (CB) chemosensory discharge leading to sympathetic overflow, autonomic dysfunction, and hypertension. Oxidative stress and pro-inflammatory molecules are involved in neurogenic models of hypertension, acting on brainstem and hypothalamic nuclei related to the cardiorespiratory control, such as the nucleus of the solitary tract, which is the primary site for the afferent inputs from the CB. Oxidative stress and pro-inflammatory molecules contribute to the activation of the CB chemoreflex pathway in CIH-induced hypertension. In this brief review, we will discuss new evidence for a critical role of oxidative stress and neuro-inflammation in development of the CIH-induced hypertension through activation of the CB chemoreflex pathway.
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Affiliation(s)
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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25
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Cho B, Spratford CM, Yoon S, Cha N, Banerjee U, Shim J. Systemic control of immune cell development by integrated carbon dioxide and hypoxia chemosensation in Drosophila. Nat Commun 2018; 9:2679. [PMID: 29992947 PMCID: PMC6041325 DOI: 10.1038/s41467-018-04990-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/08/2018] [Indexed: 02/04/2023] Open
Abstract
Drosophila hemocytes are akin to mammalian myeloid blood cells that function in stress and innate immune-related responses. A multi-potent progenitor population responds to local signals and to systemic stress by expanding the number of functional blood cells. Here we show mechanisms that demonstrate an integration of environmental carbon dioxide (CO2) and oxygen (O2) inputs that initiate a cascade of signaling events, involving multiple organs, as a stress response when the levels of these two important respiratory gases fall below a threshold. The CO2 and hypoxia-sensing neurons interact at the synaptic level in the brain sending a systemic signal via the fat body to modulate differentiation of a specific class of immune cells. Our findings establish a link between environmental gas sensation and myeloid cell development in Drosophila. A similar relationship exists in humans, but the underlying mechanisms remain to be established.
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Affiliation(s)
- Bumsik Cho
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Carrie M Spratford
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Sunggyu Yoon
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Nuri Cha
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Utpal Banerjee
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| | - Jiwon Shim
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea.
- Research Institute for Natural Science, Hanyang University, Seoul, 04763, Republic of Korea.
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, 04763, Republic of Korea.
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26
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Docio I, Olea E, Prieto-LLoret J, Gallego-Martin T, Obeso A, Gomez-Niño A, Rocher A. Guinea Pig as a Model to Study the Carotid Body Mediated Chronic Intermittent Hypoxia Effects. Front Physiol 2018; 9:694. [PMID: 29922183 PMCID: PMC5996279 DOI: 10.3389/fphys.2018.00694] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/18/2018] [Indexed: 12/12/2022] Open
Abstract
Clinical and experimental evidence indicates a positive correlation between chronic intermittent hypoxia (CIH), increased carotid body (CB) chemosensitivity, enhanced sympatho-respiratory coupling and arterial hypertension and cardiovascular disease. Several groups have reported that both the afferent and efferent arms of the CB chemo-reflex are enhanced in CIH animal models through the oscillatory CB activation by recurrent hypoxia/reoxygenation episodes. Accordingly, CB ablation or denervation results in the reduction of these effects. To date, no studies have determined the effects of CIH treatment in chemo-reflex sensitization in guinea pig, a rodent with a hypofunctional CB and lacking ventilatory responses to hypoxia. We hypothesized that the lack of CB hypoxia response in guinea pig would suppress chemo-reflex sensitization and thereby would attenuate or eliminate respiratory, sympathetic and cardiovascular effects of CIH treatment. The main purpose of this study was to assess if guinea pig CB undergoes overactivation by CIH and to correlate CIH effects on CB chemoreceptors with cardiovascular and respiratory responses to hypoxia. We measured CB secretory activity, ventilatory parameters, systemic arterial pressure and sympathetic activity, basal and in response to acute hypoxia in two groups of animals: control and 30 days CIH exposed male guinea pigs. Our results indicated that CIH guinea pig CB lacks activity elicited by acute hypoxia measured as catecholamine (CA) secretory response or intracellular calcium transients. Plethysmography data showed that only severe hypoxia (7% O2) and hypercapnia (5% CO2) induced a significant increased ventilatory response in CIH animals, together with higher oxygen consumption. Therefore, CIH exposure blunted hyperventilation to hypoxia and hypercapnia normalized to oxygen consumption. Increase in plasma CA and superior cervical ganglion CA content was found, implying a CIH induced sympathetic hyperactivity. CIH promoted cardiovascular adjustments by increasing heart rate and mean arterial blood pressure without cardiac ventricle hypertrophy. In conclusion, CIH does not sensitize CB chemoreceptor response to hypoxia but promotes cardiovascular adjustments probably not mediated by the CB. Guinea pigs could represent an interesting model to elucidate the mechanisms that underlie the long-term effects of CIH exposure to provide evidence for the role of the CB mediating pathological effects in sleep apnea diseases.
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Affiliation(s)
- Inmaculada Docio
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Valladolid, Spain
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Elena Olea
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Enfermería, Universidad de Valladolid, Valladolid, Spain
| | - Jesus Prieto-LLoret
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Valladolid, Spain
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Teresa Gallego-Martin
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Valladolid, Spain
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Obeso
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Valladolid, Spain
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Angela Gomez-Niño
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Biología Celular, Histología y Farmacología, Universidad de Valladolid, Valladolid, Spain
| | - Asuncion Rocher
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Valladolid, Spain
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
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27
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Mannée DC, Fabius TM, Wagenaar M, Eijsvogel MMM, de Jongh FHC. Reproducibility of hypercapnic ventilatory response measurements with steady-state and rebreathing methods. ERJ Open Res 2018; 4:00141-2017. [PMID: 29492407 PMCID: PMC5824331 DOI: 10.1183/23120541.00141-2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/11/2018] [Indexed: 11/06/2022] Open
Abstract
In this study, the hypercapnic ventilatory response (HCVR) was measured, defined as the ventilation response to carbon dioxide tension (PCO2). We investigated which method, rebreathing or steady-state, is most suitable for measurement of the HCVR in healthy subjects, primarily based on reproducibility. Secondary outcome parameters were subject experience and duration. 20 healthy adults performed a rebreathing and steady-state HCVR measurement on two separate days. Subject experience was assessed using numeric rating scales (NRS). The intraclass correlation coefficient (ICCs) of the sensitivity to carbon dioxide above the ventilatory recruitment threshold and the projected apnoea threshold were calculated to determine the reproducibility of both methods. The ICCs of sensitivity were 0.89 (rebreathing) and 0.56 (steady-state). The ICCs of the projected apnoea threshold were 0.84 (rebreathing) and 0.25 (steady-state). The steady-state measurement was preferred by 16 out of 20 subjects; the differences in NRS scores were small. The hypercapnic ventilatory response measured using the rebreathing setup provided reproducible results, while the steady-state method did not. This may be explained by high variability in end-tidal PCO2. Differences in subject experience between the methods are small. The hypercapnic ventilatory response measured by a rebreathing setup is reproducible, as opposed to a steady-state setuphttp://ow.ly/yGDg30hStIB
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Affiliation(s)
- Denise C Mannée
- Dept of Pulmonology, Medisch Spectrum Twente, Enschede, The Netherlands.,Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Timon M Fabius
- Dept of Pulmonology, Medisch Spectrum Twente, Enschede, The Netherlands
| | - Michiel Wagenaar
- Dept of Pulmonology, Medisch Spectrum Twente, Enschede, The Netherlands
| | | | - Frans H C de Jongh
- Dept of Pulmonology, Medisch Spectrum Twente, Enschede, The Netherlands.,Engineering Technology Faculty, University of Twente, Enschede, the Netherlands
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28
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Patinha D, Pijacka W, Paton JFR, Koeners MP. Cooperative Oxygen Sensing by the Kidney and Carotid Body in Blood Pressure Control. Front Physiol 2017; 8:752. [PMID: 29046642 PMCID: PMC5632678 DOI: 10.3389/fphys.2017.00752] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/15/2017] [Indexed: 12/13/2022] Open
Abstract
Oxygen sensing mechanisms are vital for homeostasis and survival. When oxygen levels are too low (hypoxia), blood flow has to be increased, metabolism reduced, or a combination of both, to counteract tissue damage. These adjustments are regulated by local, humoral, or neural reflex mechanisms. The kidney and the carotid body are both directly sensitive to falls in the partial pressure of oxygen and trigger reflex adjustments and thus act as oxygen sensors. We hypothesize a cooperative oxygen sensing function by both the kidney and carotid body to ensure maintenance of whole body blood flow and tissue oxygen homeostasis. Under pathological conditions of severe or prolonged tissue hypoxia, these sensors may become continuously excessively activated and increase perfusion pressure chronically. Consequently, persistence of their activity could become a driver for the development of hypertension and cardiovascular disease. Hypoxia-mediated renal and carotid body afferent signaling triggers unrestrained activation of the renin angiotensin-aldosterone system (RAAS). Renal and carotid body mediated responses in arterial pressure appear to be synergistic as interruption of either afferent source has a summative effect of reducing blood pressure in renovascular hypertension. We discuss that this cooperative oxygen sensing system can activate/sensitize their own afferent transduction mechanisms via interactions between the RAAS, hypoxia inducible factor and erythropoiesis pathways. This joint mechanism supports our view point that the development of cardiovascular disease involves afferent nerve activation.
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Affiliation(s)
- Daniela Patinha
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Wioletta Pijacka
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Maarten P Koeners
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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29
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Intra-individual variability in cerebrovascular and respiratory chemosensitivity: Can we characterize a chemoreflex “reactivity profile”? Respir Physiol Neurobiol 2017; 242:30-39. [DOI: 10.1016/j.resp.2017.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/14/2017] [Accepted: 02/24/2017] [Indexed: 01/05/2023]
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30
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Tipton MJ, Harper A, Paton JFR, Costello JT. The human ventilatory response to stress: rate or depth? J Physiol 2017. [PMID: 28650070 DOI: 10.1113/jp274596] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Many stressors cause an increase in ventilation in humans. This is predominantly reported as an increase in minute ventilation (V̇E). But, the same V̇E can be achieved by a wide variety of changes in the depth (tidal volume, VT ) and number of breaths (respiratory frequency, ƒR ). This review investigates the impact of stressors including: cold, heat, hypoxia, pain and panic on the contributions of ƒR and VT to V̇E to see if they differ with different stressors. Where possible we also consider the potential mechanisms that underpin the responses identified, and propose mechanisms by which differences in ƒR and VT are mediated. Our aim being to consider if there is an overall differential control of ƒR and VT that applies in a wide range of conditions. We consider moderating factors, including exercise, sex, intensity and duration of stimuli. For the stressors reviewed, as the stress becomes extreme V̇E generally becomes increased more by ƒR than VT . We also present some tentative evidence that the pattern of ƒR and VT could provide some useful diagnostic information for a variety of clinical conditions. In The Physiological Society's year of 'Making Sense of Stress', this review has wide-ranging implications that are not limited to one discipline, but are integrative and relevant for physiology, psychophysiology, neuroscience and pathophysiology.
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Affiliation(s)
- Michael J Tipton
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, PO1 2ER, UK
| | - Abbi Harper
- Clinical Fellow in Intensive Care Medicine, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - Joseph T Costello
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, PO1 2ER, UK
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31
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De Lange SS, Fuller A, Haw A, Hofmeyr M, Buss P, Miller M, Meyer LCR. Tremors in white rhinoceroses (<i>Ceratotherium simum</i>) during etorphine-azaperone immobilisation. J S Afr Vet Assoc 2017; 88:e1-e10. [PMID: 28281770 PMCID: PMC6138155 DOI: 10.4102/jsava.v88i0.1466] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 11/17/2016] [Accepted: 12/08/2016] [Indexed: 11/16/2022] Open
Abstract
Little is known about the mechanisms causing tremors during immobilisation of rhinoceros and whether cardiorespiratory supportive interventions alter their intensity. Therefore, we set out to determine the possible mechanisms that lead to muscle tremors and ascertain whether cardiorespiratory supportive interventions affect tremor intensity. We studied tremors and physiological responses during etorphine–azaperone immobilisation in eight boma-held and 14 free-living white rhinoceroses. Repeated measures analysis of variance and a Friedman test were used to determine differences in variables over time and between interventions. Spearman and Pearson correlations were used to test for associations between variables. Tremor intensity measured objectively by activity loggers correlated well (p < 0.0001; r2 = 0.9) with visual observations. Tremor intensity was greatest when animals were severely hypoxaemic and acidaemic. Tremor intensity correlated strongly and negatively with partial pressure of oxygen (PaO2) (p = 0.0003; r2 = 0.9995) and potential of hydrogen (pH) (p = 0.02, r2 = 0.97). It correlated strongly and positively with adrenaline concentrations (p = 0.003; r2 = 0.96), and adrenaline correlated strongly and negatively with PaO2 (p = 0.03; r2 = 0.95) and pH (p = 0.03; r2 = 0.94). Therefore, hypoxaemia and acidaemia were likely associated with the intensity of tremors through their activation of the release of tremorgenic levels of adrenaline. Tremors can be reduced if circulating adrenaline is reduced, and this can be achieved by the administration of butorphanol plus oxygen insufflation. Furthermore, to assist with reducing the risks associated with rhinoceros immobilisation, tremor intensity could be used as a clinical indicator of respiratory and metabolic compromise.
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Affiliation(s)
| | | | | | | | | | | | - Leith C R Meyer
- Department of Paraclinical Sciences, University of Pretoria; School of Physiology, University of the Witwatersrand.
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32
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Disharmony between wake- and respiration-promoting activities: effects of modafinil on ventilatory control in rodents. Respir Res 2016; 17:148. [PMID: 27842553 PMCID: PMC5109771 DOI: 10.1186/s12931-016-0466-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/02/2016] [Indexed: 11/24/2022] Open
Abstract
Background Modafinil is a wake-promoting drug and has been widely used for daytime sleepiness in patients with narcolepsy and other sleep disorders. A recent case series reported that daily oral modafinil alleviated hypercapnic respiratory failure in patients with COPD. However, the precise action of modafinil on respiration such as hypercapnic and/or hypoxic ventilatory responses remains unclear. The aim of this study is to clarify the effect of modafinil on the ventilatory control. Methods We investigated the hypothesis that modafinil enhances resting ventilation as well as the stimulatory ventilatory responses to hypercapnia and hypoxia. We addressed the issue by examining minute ventilation, respiratory rate and volume components using plethysmography, combined with a concurrent EEG monitoring of the level of wakefulness before and after administration of modafinil in two doses of 100 mg/kg and 200 mg/kg in unanesthetized mice. In addition, we monitored the effect of the lower dose of modafinil on mice locomotor activity in a freely moving condition by video-recording. Results Wakefulness, locomotor activity and variability of the breathing pattern in tidal volume were promoted by both doses of modafinil. Neither dose of modafinil increased the absolute values of resting ventilation or promoted the ventilatory responses to hypercapnia and hypoxia. Rather, higher dose of modafinil slightly suppressed respiratory rate in room air condition. Conclusions Modafinil is conducive to the state of wakefulness but does not augment resting ventilation or the hyperventilatory responses to chemical stimuli in unanesthetized rodents. Electronic supplementary material The online version of this article (doi:10.1186/s12931-016-0466-9) contains supplementary material, which is available to authorized users.
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33
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Jackson KL, Dhaibar HA, Dayton RD, Cananzi SG, Mayhan WG, Glasscock E, Klein RL. Severe respiratory changes at end stage in a FUS-induced disease state in adult rats. BMC Neurosci 2016; 17:69. [PMID: 27793099 PMCID: PMC5086065 DOI: 10.1186/s12868-016-0304-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/19/2016] [Indexed: 12/12/2022] Open
Abstract
Background Fused in sarcoma (FUS) is an RNA-binding protein associated with the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration. ALS manifests in patients as a progressive paralysis which leads to respiratory dysfunction and failure, the primary cause of death in ALS. We expressed human FUS in rats to determine if FUS would induce ALS relevant respiratory changes to serve as an early stage disease indicator. The FUS expression was initiated in adult rats by way of an intravenously administered adeno-associated virus vector serotype 9 (AAV9) providing an adult onset model. Results The rats developed progressive motor impairments observed as early as 2–3 weeks post gene transfer. Respiratory abnormalities manifested 4–7 weeks post gene transfer including increased respiratory frequency and decreased tidal volume. Rats with breathing abnormalities also had arterial blood acidosis. Similar detailed plethysmographic changes were found in adult rats injected with AAV9 TDP-43. FUS gene transfer to adult rats yielded a consistent pre-clinical model with relevant motor paralysis in the early to middle stages and respiratory dysfunction at the end stage. Both FUS and TDP-43 yielded a similar consistent disease state. Conclusions This modeling method yields disease relevant motor and respiratory changes in adult rats. The reproducibility of the data supports the use of this method to study other disease related genes and their combinations as well as a platform for disease modifying interventional strategies.
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Affiliation(s)
- Kasey L Jackson
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA.
| | - Hemangini A Dhaibar
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA
| | - Robert D Dayton
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA
| | - Sergio G Cananzi
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA
| | - William G Mayhan
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA
| | - Edward Glasscock
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA
| | - Ronald L Klein
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Hwy, Shreveport, LA, 71130, USA
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34
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Alcayaga J, Oyarce MP, Del Rio R. Chronic phenytoin treatment reduces rat carotid body chemosensory responses to acute hypoxia. Brain Res 2016; 1649:38-43. [DOI: 10.1016/j.brainres.2016.08.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/16/2016] [Accepted: 08/20/2016] [Indexed: 10/21/2022]
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35
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Tubek S, Niewinski P, Reczuch K, Janczak D, Rucinski A, Paleczny B, Engelman ZJ, Banasiak W, Paton JFR, Ponikowski P. Effects of selective carotid body stimulation with adenosine in conscious humans. J Physiol 2016; 594:6225-6240. [PMID: 27435894 DOI: 10.1113/jp272109] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/12/2016] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS In humans, excitation of peripheral chemoreceptors with systemic hypoxia causes hyperventilation, hypertension and tachycardia. However, the contribution of particular chemosensory areas (carotid vs. aortic bodies) to this response is unclear. We showed that selective stimulation of the carotid body by the injection of adenosine into the carotid artery causes a dose-dependent increase in minute ventilation and blood pressure with a concomitant decrease in heart rate in conscious humans. The ventilatory response was abolished and the haemodynamic response was diminished following carotid body ablation. We found that the magnitude of adenosine evoked responses in minute ventilation and blood pressure was analogous to the responses evoked by hypoxia. By contrast, opposing heart rate responses were evoked by adenosine (bradycardia) vs. hypoxia (tachycardia). Intra-carotid adenosine administration may provide a novel method for perioperative assessment of the effectiveness of carotid body ablation, which has been recently proposed as a treatment strategy for sympathetically-mediated diseases. ABSTRACT Stimulation of peripheral chemoreceptors by acute hypoxia causes an increase in minute ventilation (VI), heart rate (HR) and arterial blood pressure (BP). However, the contribution of particular chemosensory areas, such as carotid (CB) vs. aortic bodies, to this response in humans remains unknown. We performed a blinded, randomized and placebo-controlled study in 11 conscious patients (nine men, two women) undergoing common carotid artery angiography. Doses of adenosine ranging from 4 to 512 μg or placebo solution of a matching volume were administered in randomized order via a diagnostic catheter located in a common carotid artery. Separately, ventilatory and haemodynamic responses to systemic hypoxia were also assessed. Direct excitation of a CB with intra-arterial adenosine increased VI, systolic BP, mean BP and decreased HR. No responses in these variables were seen after injections of placebo. The magnitude of the ventilatory and haemodynamic responses depended on both the dose of adenosine used and on the level of chemosensitivity as determined by the ventilatory response to hypoxia. Percutaneous radiofrequency ablation of the CB abolished the adenosine evoked respiratory response and partially depressed the cardiovascular response in one participant. The results of the present study confirm the excitatory role of purines in CB physiology in humans and suggest that adenosine may be used for selective stimulation and assessment of CB activity. The trial is registered at ClinicalTrials.gov NCT01939912.
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Affiliation(s)
- Stanislaw Tubek
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland. .,Department of Heart Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland.
| | - Piotr Niewinski
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Krzysztof Reczuch
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.,Department of Heart Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
| | - Dariusz Janczak
- Department of Vascular Surgery, 4th Military Hospital, Wroclaw, Poland.,Department of Clinical Proceedings, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
| | - Artur Rucinski
- Department of Vascular Surgery, 4th Military Hospital, Wroclaw, Poland
| | | | | | - Waldemar Banasiak
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Piotr Ponikowski
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.,Department of Heart Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
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Zhao L, Zhuang J, Gao X, Ye C, Lee LY, Xu F. From the Cover: Prenatal Nicotinic Exposure Attenuates Respiratory Chemoreflexes Associated With Downregulation of Tyrosine Hydroxylase and Neurokinin 1 Receptor in Rat Pup Carotid Body. Toxicol Sci 2016; 153:103-11. [PMID: 27329243 PMCID: PMC5841596 DOI: 10.1093/toxsci/kfw108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Maternal cigarette smoke is the major risk of sudden infant death syndrome (SIDS). A depressed ventilatory response to hypoxia (HVR) and hypercapnia (HCVR) is thought to be responsible for the pathogenesis of SIDS and the carotid body is critically involved in these responses. We have recently reported that prenatal nicotinic exposure (PNE) over the full gestation induces depressed HVR in rat pups. Here, we asked whether PNE (1) depressed not only HVR but also HCVR that were dependent on the carotid body, (2) affected some important receptors and neurochemicals expressed in the carotid body, such as tyrosine hydroxylase (TH), neurokinin-1 receptor (NK1R), and α7 nicotinic acetylcholine receptor (α7nAChR), and (3) blunted the ventilatory responses to activation of these receptors. To this end, HVR and HCVR in Ctrl and PNE pups were measured with plethysmography before and after carotid body ablation (Series I), mRNA expression and/or immunoreactivity (IR) of TH, NK1R, and α7nAChR in the carotid body were examined by RT-PCR and immunohistochemistry (Series II), and the ventilatory responses were tested before and after intracarotid injection of substance P (NK1R agonist) and AR-R17779 (α7nAChR agonist) (Series III). Our results showed that PNE (1) significantly depressed both HVR and HCVR and these depressions were abolished by carotid body ablation, (2) reduced the relative population of glomus cells, mRNA NK1R, and α7nAChR and IR of NK1R and TH in the carotid body, and (3) decreased ventilatory responses to intracarotid injection of substance P or AR-R17779. These results suggest that PNE acting via the carotid body could strikingly blunt HVR and HCVR, likely through downregulating TH and NK1R.
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Affiliation(s)
- Lei Zhao
- *Lovelace Respiratory Research Institute, Pathophysiology Program, Albuquerque, New Mexico 87108
| | - Jianguo Zhuang
- *Lovelace Respiratory Research Institute, Pathophysiology Program, Albuquerque, New Mexico 87108
| | - Xiuping Gao
- *Lovelace Respiratory Research Institute, Pathophysiology Program, Albuquerque, New Mexico 87108
| | - Chunyan Ye
- *Lovelace Respiratory Research Institute, Pathophysiology Program, Albuquerque, New Mexico 87108
| | - Lu-Yuan Lee
- Department of Physiology, University of Kentucky Medical Center, Lexington, Kentucky 40536
| | - Fadi Xu
- *Lovelace Respiratory Research Institute, Pathophysiology Program, Albuquerque, New Mexico 87108
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Does the Sympathetic Nervous System Adapt to Chronic Altitude Exposure? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:375-93. [DOI: 10.1007/978-1-4899-7678-9_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Sforza E, Roche F. Chronic intermittent hypoxia and obstructive sleep apnea: an experimental and clinical approach. HYPOXIA (AUCKLAND, N.Z.) 2016; 4:99-108. [PMID: 27800512 PMCID: PMC5085272 DOI: 10.2147/hp.s103091] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Obstructive sleep apnea (OSA) is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences, such as systemic arterial hypertension, ischemic heart disease, cardiac arrhythmias, metabolic disorders, and cognitive dysfunction. The pathogenesis of OSA-related consequence is assumed to be chronic intermittent hypoxia (IH) inducing alterations at the molecular level, oxidative stress, persistent systemic inflammation, oxygen sensor activation, and increase of sympathetic activity. Overall, these mechanisms have an effect on vessel permeability and are considered to be important factors for explaining vascular, metabolic, and cognitive OSA-related consequences. The present review attempts to examine together the research paradigms and clinical studies on the effect of acute and chronic IH and the potential link with OSA. We firstly describe the literature data on the mechanisms activated by acute and chronic IH at the experimental level, which are very helpful and beneficial to explaining OSA consequences. Then, we describe in detail the effect of IH in patients with OSA that we can consider "the human model" of chronic IH. In this way, we can better understand the specific pathophysiological mechanisms proposed to explain the consequences of IH in OSA.
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Affiliation(s)
- Emilia Sforza
- Service de Physiologie Clinique et de l’Exercice, Pole NOL, CHU, EA SNA-EPIS 4607, Faculté de Médecine J. Lisfranc, UJM Saint-Etienne, Université de Lyon, Saint-Etienne, France
| | - Fréderic Roche
- Service de Physiologie Clinique et de l’Exercice, Pole NOL, CHU, EA SNA-EPIS 4607, Faculté de Médecine J. Lisfranc, UJM Saint-Etienne, Université de Lyon, Saint-Etienne, France
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Prabhakar NR, Peng YJ, Kumar GK, Nanduri J. Peripheral chemoreception and arterial pressure responses to intermittent hypoxia. Compr Physiol 2016; 5:561-77. [PMID: 25880505 DOI: 10.1002/cphy.c140039] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen levels, and the resulting chemoreflex is a potent regulator of blood pressure. Recurrent apnea with intermittent hypoxia (IH) is a major clinical problem in adult humans and infants born preterm. Adult patients with recurrent apnea exhibit heightened sympathetic nerve activity and hypertension. Adults born preterm are predisposed to early onset of hypertension. Available evidence suggests that carotid body chemoreflex contributes to hypertension caused by IH in both adults and neonates. Experimental models of IH provided important insights into cellular and molecular mechanisms underlying carotid body chemoreflex-mediated hypertension. This article provides a comprehensive appraisal of how IH affects carotid body function, underlying cellular, molecular, and epigenetic mechanisms, and the contribution of chemoreflex to the hypertension.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, Illinois, USA
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40
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Golder FJ, Dax S, Baby SM, Gruber R, Hoshi T, Ideo C, Kennedy A, Peng S, Puskovic V, Ritchie D, Woodward R, Wardle RL, Van Scott MR, Mannion JC, MacIntyre DE. Identification and Characterization of GAL-021 as a Novel Breathing Control Modulator. Anesthesiology 2015; 123:1093-104. [PMID: 26352381 DOI: 10.1097/aln.0000000000000844] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND The authors describe the preclinical pharmacological properties of GAL-021, a novel peripheral chemoreceptor modulator. METHODS The ventilatory effects of GAL-021 were characterized using tracheal pneumotachometry (n = 4 to 6), plethysmography (n = 5 to 6), arterial blood gas analyses (n = 6 to 11), and nasal capnography (n = 3 to 4) in naive animals and those subjected to morphine-induced respiratory depression. Morphine analgesia in rats was evaluated by tail-flick test (n = 6). Carotid body involvement in GAL-021 ventilatory effects was assessed by comparing responses in intact and carotid sinus nerve-transected rats. Hemodynamic effects of GAL-021 were evaluated in urethane-anesthetized rats (n = 7). The pharmacological profile of GAL-021 in vitro was investigated using radioligand binding, enzyme inhibition, and cellular electrophysiology assays. RESULTS GAL-021 given intravenously stimulated ventilation and/or attenuated opiate-induced respiratory depression in rats, mice, and nonhuman primates, without decreasing morphine analgesia in rats. GAL-021 did not alter mean arterial pressure but produced a modest increase in heart rate. Ventilatory stimulation in rats was attenuated by carotid sinus nerve transection. GAL-021 inhibited KCa1.1 in GH3 cells, and the evoked ventilatory stimulation was attenuated in Slo1 mice lacking the pore-forming α-subunit of the KCa1.1 channel. CONCLUSIONS GAL-021 behaved as a breathing control modulator in rodents and nonhuman primates and diminished opioid-induced respiratory depression without compromising opioid analgesia. It acted predominantly at the carotid body, in part by inhibiting KCa1.1 channels. Its preclinical profile qualified the compound to enter clinical trials to assess effects on breathing control disorders such as drug (opioid)-induced respiratory depression and sleep apnea.
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Affiliation(s)
- Francis J Golder
- From the Department of Drug Discovery, Galleon Pharmaceuticals, Inc., Horsham, Pennsylvania (F.J.G., S.D., S.M.B., R.G., C.I., A.K., S.P., V.P., D.R., R.W., J.C.M., D.E.M.); Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania (T.H.); and Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina (R.L.W., M.R.V.S.)
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Mishra A, Mohammad G, Norboo T, Newman JH, Pasha MAQ. Lungs at high-altitude: genomic insights into hypoxic responses. J Appl Physiol (1985) 2015; 119:1-15. [DOI: 10.1152/japplphysiol.00513.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 04/20/2015] [Indexed: 11/22/2022] Open
Abstract
Hypobaric hypoxia at high altitude (HA) results in reduced blood arterial oxygen saturation, perfusion of organs with hypoxemic blood, and direct hypoxia of lung tissues. The pulmonary complications in the cells of the pulmonary arterioles due to hypobaric hypoxia are the basis of the pathophysiological mechanisms of high-altitude pulmonary edema (HAPE). Some populations that have dwelled at HA for thousands of years have evolutionarily adapted to this environmental stress; unadapted populations may react with excessive physiological responses that impair health. Individual variations in response to hypoxia and the mechanisms of HA adaptation provide insight into physiological responses. Adaptive and maladaptive responses include alterations in pathways such as oxygen sensing, hypoxia signaling, K+- and Ca2+-gated channels, redox balance, and the renin-angiotensin-aldosterone system. Physiological imbalances are linked with genetic susceptibilities, and nonhomeostatic responses in gene regulation that occur by small RNAs, histone modification, and DNA methylation predispose susceptible humans to these HA illnesses. Elucidation of the interaction of these factors will lead to a more comprehensive understanding of HA adaptations and maladaptations and will lead to new therapeutics for HA disorders related to hypoxic lungs.
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Affiliation(s)
- Aastha Mishra
- Department of Genomics and Molecular Medicine, Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
- Department of Biotechnology, University of Pune, Pune, India
| | - Ghulam Mohammad
- Department of Medicine, SNM Hospital, Leh, Ladakh, J&K, India
| | - Tsering Norboo
- Ladakh Institute of Prevention, Leh, Ladakh, J&K, India; and
| | - John H. Newman
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - M. A. Qadar Pasha
- Department of Genomics and Molecular Medicine, Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
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Abstract
While modernization has dramatically increased lifespan, it has also witnessed the increasing prevalence of diseases such as obesity, hypertension, and type 2 diabetes. Such chronic, acquired diseases result when normal physiologic control goes awry and may thus be viewed as failures of homeostasis. However, while nearly every process in human physiology relies on homeostatic mechanisms for stability, only some have demonstrated vulnerability to dysregulation. Additionally, chronic inflammation is a common accomplice of the diseases of homeostasis, yet the basis for this connection is not fully understood. Here we review the design of homeostatic systems and discuss universal features of control circuits that operate at the cellular, tissue, and organismal levels. We suggest a framework for classification of homeostatic signals that is based on different classes of homeostatic variables they report on. Finally, we discuss how adaptability of homeostatic systems with adjustable set points creates vulnerability to dysregulation and disease. This framework highlights the fundamental parallels between homeostatic and inflammatory control mechanisms and provides a new perspective on the physiological origin of inflammation.
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Affiliation(s)
- Maya E Kotas
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT USA
| | - Ruslan Medzhitov
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT USA.
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43
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Reyes C, Fong AY, Milsom WK. Distribution and innervation of putative peripheral arterial chemoreceptors in the red-eared slider (Trachemys scripta elegans). J Comp Neurol 2015; 523:1399-418. [DOI: 10.1002/cne.23743] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 01/07/2015] [Accepted: 01/07/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Catalina Reyes
- Department of Zoology; University of British Columbia; Vancouver British Columbia, Vancouver Canada V6T 1Z4
| | - Angelina Y. Fong
- Department of Physiology; University of Melbourne; Parkville Victoria 3010 Australia
| | - William K. Milsom
- Department of Zoology; University of British Columbia; Vancouver British Columbia, Vancouver Canada V6T 1Z4
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Mazzatenta A, Marconi GD, Macchi V, Porzionato A, Cataldi A, Di Giulio C, Pokorski M. Coexpression of Galanin and Nestin in the Chemoreceptor Cells of the Human Carotid Body. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 885:77-82. [PMID: 26747071 DOI: 10.1007/5584_2015_189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The carotid body is a highly specialized chemoreceptive organ of neural crest origin whose role is to detect changes in arterial oxygen content. The sensory units are the chemoreceptor cells, which are neuronal-like cells, surrounded by sustentacular or glial-like cells. It is suggested that the carotid body contains self-renewing multipotent stem cells, which are putatively represented by glial-like sustentacular cells. The mechanisms of renewal of neuronal-like cells are unclear. Recently, we have demonstrated the expression of galanin, a peptide promoting neurogenesis, in chemoreceptor cells in the human CB. Thus, in the present study we seek to determine whether galanin expression in chemoreceptor cells could be matched with that of nestin, a peptide that is a marker of multipotent neural stem cells, or rather with the glial fibrillary acidic protein (GFAP), a marker for glial cells. The latter would underscore the pluasibly essential role of sustentacular cells in the self-renewal capability of chemorecetors. We found that galanin expression is matched with nestin in chemoreceptor cells of the human carotid body, but not with that of GFAP. Thus, galanin expression in chemoreceptor cells could provide a signal for neurogenesis and chemoreceptor cell differentiation in the carotid body.
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Affiliation(s)
- Andrea Mazzatenta
- Department of Neurosciences, Imaging and Clinical Science, University of Chieti-Pescara, Chieti, Italy.
| | - Guya D Marconi
- Department of Drug Sciences, University of Chieti-Pescara, Chieti, Italy
| | - Veronica Macchi
- Department of Human Anatomy and Physiology, Padua University, Padua, Italy
| | - Andrea Porzionato
- Department of Human Anatomy and Physiology, Padua University, Padua, Italy
| | - Amelia Cataldi
- Department of Drug Sciences, University of Chieti-Pescara, Chieti, Italy
| | - Camillo Di Giulio
- Department of Neurosciences, Imaging and Clinical Science, University of Chieti-Pescara, Chieti, Italy
| | - Mieczyslaw Pokorski
- Institute of Nursing, Public Higher Medical Professional School, 68 Katowicka St., 45-060, Opole, Poland.
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45
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Wehrwein EA, Limberg JK, Taylor JL, Dube S, Basu A, Basu R, Rizza RA, Curry TB, Joyner MJ. Effect of bilateral carotid body resection on the counterregulatory response to hypoglycaemia in humans. Exp Physiol 2014; 100:69-78. [DOI: 10.1113/expphysiol.2014.083154] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/04/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Erica A. Wehrwein
- Department of Physiology; Michigan State University; East Lansing MI USA
| | | | | | - Simmi Dube
- Department of Endocrinology; Mayo Clinic; Rochester MN USA
| | - Ananda Basu
- Department of Endocrinology; Mayo Clinic; Rochester MN USA
| | - Rita Basu
- Department of Endocrinology; Mayo Clinic; Rochester MN USA
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Mazzatenta A, Marconi GD, Zara S, Cataldi A, Porzionato A, Di Giulio C. In the carotid body, galanin is a signal for neurogenesis in young, and for neurodegeneration in the old and in drug-addicted subjects. Front Physiol 2014; 5:427. [PMID: 25400591 PMCID: PMC4215693 DOI: 10.3389/fphys.2014.00427] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 10/14/2014] [Indexed: 12/11/2022] Open
Abstract
The carotid body is a highly specialized chemoreceptive structure for the detection of and reaction to hypoxia, through induction of an increase in hypoxia inducible factor. As tissue hypoxia increases with aging and can have dramatic effects in respiratory depression induced by drug addiction, we investigated the carotid body in young and old healthy subjects in comparison with drug-addicted subjects, including the expression of the neurotransmitter galanin. Galanin expression was recently reported for neuronal-like cells of the human carotid body, and it is implicated in several functions in neurons. In particular, this includes the regulation of differentiation of neural stem cells, and participation in the development and plasticity of the nervous system. Using immunohistochemistry detection, we demonstrate that galanin expression in the human carotid body in healthy older subjects and drug-addicted subjects is significantly reduced in comparison with healthy young subjects. This demonstrates not only the effects of normal aging and senescence, but also in the drug-addicted subjects, this appears to be due to a disorganization of the chemo-sensory region. With both aging and drug addiction, this results in a physiological reduction in neuronal-like cells, coupled with interlobular and intralobular increases in connective tissue fibers. Consequently, in both aging and drug addiction, this reduction of neuronal-like cells and the regeneration suggest that the carotid body is losing its sensory capabilities, with the transmission of chemoreceptive signals dramatically and vitally reduced. The level of galanin expression would thus provide a signal for neurogenesis in young subjects, and for neurodegeneration in older and drug-addicted subjects.
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Affiliation(s)
- Andrea Mazzatenta
- Physiology and Physiopathology Section, Department of Neurosciences, Imaging and Clinical Science, University of Chieti-Pescara Chieti, Italy
| | - Guya D Marconi
- Department of Drug Sciences, University of Chieti-Pescara Chieti, Italy
| | - Susi Zara
- Department of Drug Sciences, University of Chieti-Pescara Chieti, Italy
| | - Amelia Cataldi
- Department of Drug Sciences, University of Chieti-Pescara Chieti, Italy
| | - Andrea Porzionato
- Department of Human Anatomy and Physiology, University of Padua Padua, Italy
| | - Camillo Di Giulio
- Physiology and Physiopathology Section, Department of Neurosciences, Imaging and Clinical Science, University of Chieti-Pescara Chieti, Italy
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Abstract
SIGNIFICANCE Voltage-gated K+ channels are a large family of K+-selective ion channel protein complexes that open on membrane depolarization. These K+ channels are expressed in diverse tissues and their function is vital for numerous physiological processes, in particular of neurons and muscle cells. Potentially reversible oxidative regulation of voltage-gated K+ channels by reactive species such as reactive oxygen species (ROS) represents a contributing mechanism of normal cellular plasticity and may play important roles in diverse pathologies including neurodegenerative diseases. RECENT ADVANCES Studies using various protocols of oxidative modification, site-directed mutagenesis, and structural and kinetic modeling provide a broader phenomenology and emerging mechanistic insights. CRITICAL ISSUES Physicochemical mechanisms of the functional consequences of oxidative modifications of voltage-gated K+ channels are only beginning to be revealed. In vivo documentation of oxidative modifications of specific amino-acid residues of various voltage-gated K+ channel proteins, including the target specificity issue, is largely absent. FUTURE DIRECTIONS High-resolution chemical and proteomic analysis of ion channel proteins with respect to oxidative modification combined with ongoing studies on channel structure and function will provide a better understanding of how the function of voltage-gated K+ channels is tuned by ROS and the corresponding reducing enzymes to meet cellular needs.
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Affiliation(s)
- Nirakar Sahoo
- 1 Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital , Jena, Germany
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48
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Reyes C, Fong AY, Brink DL, Milsom WK. Distribution and innervation of putative arterial chemoreceptors in the bullfrog (Rana catesbeiana). J Comp Neurol 2014; 522:3754-74. [PMID: 24954002 DOI: 10.1002/cne.23640] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/31/2014] [Accepted: 06/16/2014] [Indexed: 01/27/2023]
Abstract
Peripheral arterial chemoreceptors have been located previously in the carotid labyrinth, the aortic arch, and the pulmocutaneous artery of frogs. In the present study we used cholera toxin B neuronal tract tracing and immunohistochemical markers for cholinergic cells (vesicular acetylcholine transporter [VAChT]), tyrosine hydroxylase (TH), and serotonin (5HT) to identify putative O2-sensing cells in Rana catesbeiana. We found potential O2-sensing cells in all three vascular areas innervated by branches of the vagus nerve, whereas only cells in the carotid labyrinth were innervated by the glossopharyngeal nerve. Cells containing either 5HT or TH were found in all three sites, whereas cells containing both neurotransmitters were found only in the carotid labyrinth. Cell bodies containing VAChT were not found at any site. The morphology and innervation of putative O2-sensing cells were similar to those of glomus cells found in other vertebrates. The presence of 5HT- and TH-immunoreactive cells in the aorta, pulmocutaneous artery, and carotid labyrinth appears to reflect a phylogenetic transition between the major neurotransmitter seen in the putative O2-sensing cells of fish (5HT) and those found in the glomus cells of mammals (acetylcholine, adenosine, and catecholamines).
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Affiliation(s)
- Catalina Reyes
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Vancouver, V6T 1Z4, Canada
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49
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Yokoyama T, Nakamuta N, Kusakabe T, Yamamoto Y. Vesicular glutamate transporter 2-immunoreactive afferent nerve terminals in the carotid body of the rat. Cell Tissue Res 2014; 358:271-5. [DOI: 10.1007/s00441-014-1921-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/15/2014] [Indexed: 01/24/2023]
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50
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Neuronal control of metabolism through nutrient-dependent modulation of tracheal branching. Cell 2014; 156:69-83. [PMID: 24439370 PMCID: PMC3898607 DOI: 10.1016/j.cell.2013.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/26/2013] [Accepted: 11/05/2013] [Indexed: 12/30/2022]
Abstract
During adaptive angiogenesis, a key process in the etiology and treatment of cancer and obesity, the vasculature changes to meet the metabolic needs of its target tissues. Although the cues governing vascular remodeling are not fully understood, target-derived signals are generally believed to underlie this process. Here, we identify an alternative mechanism by characterizing the previously unrecognized nutrient-dependent plasticity of the Drosophila tracheal system: a network of oxygen-delivering tubules developmentally akin to mammalian blood vessels. We find that this plasticity, particularly prominent in the intestine, drives—rather than responds to—metabolic change. Mechanistically, it is regulated by distinct populations of nutrient- and oxygen-responsive neurons that, through delivery of both local and systemic insulin- and VIP-like neuropeptides, sculpt the growth of specific tracheal subsets. Thus, we describe a novel mechanism by which nutritional cues modulate neuronal activity to give rise to organ-specific, long-lasting changes in vascular architecture. The Drosophila tracheal system exhibits nutrient-dependent plasticity Tracheal plasticity is organ specific and metabolically significant Nutrient- and hypoxia-responsive neurons drive adaptive tracheation Distinct insulin-like and Pdf neuropeptides control organ-specific tracheal branching
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