1
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Barrett KT, Roy A, Ebdalla A, Pittman QJ, Wilson RJA, Scantlebury MH. The Impact of Inflammation on Thermal Hyperpnea: Relevance for Heat Stress and Febrile Seizures. Am J Respir Cell Mol Biol 2024; 71:195-206. [PMID: 38597725 PMCID: PMC11299082 DOI: 10.1165/rcmb.2023-0451oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/09/2024] [Indexed: 04/11/2024] Open
Abstract
Extreme heat caused by climate change is increasing the transmission of infectious diseases, resulting in a sharp rise in heat-related illness and mortality. Understanding the mechanistic link between heat, inflammation, and disease is thus important for public health. Thermal hyperpnea, and consequent respiratory alkalosis, is crucial in febrile seizures and convulsions induced by heat stress in humans. Here, we address what causes thermal hyperpnea in neonates and how it is affected by inflammation. Transient receptor potential cation channel subfamily V member 1 (TRPV1), a heat-activated channel, is sensitized by inflammation and modulates breathing and thus may play a key role. To investigate whether inflammatory sensitization of TRPV1 modifies neonatal ventilatory responses to heat stress, leading to respiratory alkalosis and an increased susceptibility to hyperthermic seizures, we treated neonatal rats with bacterial LPS, and breathing, arterial pH, in vitro vagus nerve activity, and seizure susceptibility were assessed during heat stress in the presence or absence of a TRPV1 antagonist (AMG-9810) or shRNA-mediated TRPV1 suppression. LPS-induced inflammatory preconditioning lowered the threshold temperature and latency of hyperthermic seizures. This was accompanied by increased tidal volume, minute ventilation, expired CO2, and arterial pH (alkalosis). LPS exposure also elevated vagal spiking and intracellular calcium concentrations in response to hyperthermia. TRPV1 inhibition with AMG-9810 or shRNA reduced the LPS-induced susceptibility to hyperthermic seizures and altered the breathing pattern to fast shallow breaths (tachypnea), making each breath less efficient and restoring arterial pH. These results indicate that inflammation exacerbates thermal hyperpnea-induced respiratory alkalosis associated with increased susceptibility to hyperthermic seizures, primarily mediated by TRPV1 localized to vagus neurons.
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Affiliation(s)
- Karlene T. Barrett
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Pediatrics
| | - Arijit Roy
- Hotchkiss Brain Institute
- Department of Physiology and Pharmacology, and
| | - Aya Ebdalla
- Alberta Children’s Hospital Research Institute
| | - Quentin J. Pittman
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Physiology and Pharmacology, and
| | - Richard J. A. Wilson
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Physiology and Pharmacology, and
| | - Morris H. Scantlebury
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Pediatrics
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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2
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Joana Alves M, Browe BM, Carolina Rodrigues Dias A, Torres JM, Zaza G, Bangudi S, Blackburn J, Wang W, de Araujo Fernandes-Junior S, Fadda P, Toland A, Baer LA, Stanford KI, Czeisler C, Garcia AJ, Javier Otero J. Metabolic trade-offs in Neonatal sepsis triggered by TLR4 and TLR1/2 ligands result in unique dysfunctions in neural breathing circuits. Brain Behav Immun 2024; 119:333-350. [PMID: 38561095 DOI: 10.1016/j.bbi.2024.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/05/2024] [Accepted: 03/17/2024] [Indexed: 04/04/2024] Open
Abstract
Neonatal sepsis remains one of the leading causes of mortality in newborns. Several brainstem-regulated physiological processes undergo disruption during neonatal sepsis. Mechanistic knowledge gaps exist at the interplay between metabolism and immune activation to brainstem neural circuits and pertinent physiological functions in neonates. To delineate this association, we induced systemic inflammation either by TLR4 (LPS) or TLR1/2 (PAM3CSK4) ligand administration in postnatal day 5 mice (PD5). Our findings show that LPS and PAM3CSK4 evoke substantial changes in respiration and metabolism. Physiological trade-offs led to hypometabolic-hypothermic responses due to LPS, but not PAM3CSK4, whereas to both TLR ligands blunted respiratory chemoreflexes. Neuroinflammatory pathways modulation in brainstem showed more robust effects in LPS than PAM3CSK4. Brainstem neurons, microglia, and astrocyte gene expression analyses showed unique responses to TLR ligands. PAM3CSK4 did not significantly modulate gene expression changes in GLAST-1 positive brainstem astrocytes. PD5 pups receiving PAM3CSK4 failed to maintain a prolonged metabolic state repression, which correlated to enhanced gasping latency and impaired autoresuscitation during anoxic chemoreflex challenges. In contrast, LPS administered pups showed no significant changes in anoxic chemoreflex. Electrophysiological studies from brainstem slices prepared from pups exposed to either TLR4 or PAM3CSK4 showed compromised transmission between preBötzinger complex and Hypoglossal as an exclusive response to the TLR1/2 ligand. Spatial gene expression analysis demonstrated a region-specific modulation of PAM3CSK4 within the raphe nucleus relative to other anatomical sites evaluated. Our findings suggest that metabolic changes due to inflammation might be a crucial tolerance mechanism for neonatal sepsis preserving neural control of breathing.
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Affiliation(s)
- Michele Joana Alves
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Brigitte M Browe
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Neuroscience Institute, The University of Chicago, Chicago, IL, United States
| | - Ana Carolina Rodrigues Dias
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Juliet M Torres
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Giuliana Zaza
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Suzy Bangudi
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Jessica Blackburn
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Wesley Wang
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | | | - Paolo Fadda
- Genomics Shared Resource, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States
| | - Amanda Toland
- Genomics Shared Resource, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States; Department of Cancer Biology and Genetics and Division of Human Genetics, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Lisa A Baer
- Department of Cancer Biology and Genetics and Division of Human Genetics, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Kristin I Stanford
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Catherine Czeisler
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Alfredo J Garcia
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Neuroscience Institute, The University of Chicago, Chicago, IL, United States.
| | - José Javier Otero
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, United States.
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3
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Taylor CE, Mendenhall LE, Sunshine MD, Wilson JN, Calulot CM, Sun RC, Johnson LA, Alilain WJ. Sex and APOE genotype influence respiratory function under hypoxic and hypoxic-hypercapnic conditions. J Neurophysiol 2024; 132:23-33. [PMID: 38748407 DOI: 10.1152/jn.00255.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 04/12/2024] [Accepted: 05/08/2024] [Indexed: 06/12/2024] Open
Abstract
The apolipoprotein E (APOE) gene has been studied due to its influence on Alzheimer's disease (AD) development and work in an APOE mouse model recently demonstrated impaired respiratory motor plasticity following spinal cord injury (SCI). Individuals with AD often copresent with obstructive sleep apnea (OSA) characterized by cessations in breathing during sleep. Despite the prominence of APOE genotype and sex as factors in AD progression, little is known about the impact of these variables on respiratory control. Ventilation is tightly regulated across many systems, with respiratory rhythm formation occurring in the brainstem but modulated in response to chemoreception. Alterations within these modulatory systems may result in disruptions of appropriate respiratory control and ultimately, disease. Using mice expressing two different humanized APOE alleles, we characterized how sex and the presence of APOE3 or APOE4 influences ventilation during baseline breathing (normoxia) and during respiratory challenges. We show that sex and APOE genotype influence breathing during hypoxic challenge, which may have clinical implications in the context of AD and OSA. In addition, female mice, while responding robustly to hypoxia, were unable to recover to baseline respiratory levels, emphasizing sex differences in disordered breathing.NEW & NOTEWORTHY This study is the first to use whole body plethysmography (WBP) to measure the impact of APOE alleles on breathing under normoxia and during adverse respiratory challenges in a targeted replacement Alzheimer's model. Both sex and genotype were shown to affect breathing under normoxia, hypoxic challenge, and hypoxic-hypercapnic challenge. This work has important implications regarding the impact of genetics on respiratory control as well as applications pertaining to conditions of disordered breathing including sleep apnea and neurotrauma.
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Affiliation(s)
- Chase E Taylor
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Laura E Mendenhall
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Michael D Sunshine
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Jessica N Wilson
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Chris M Calulot
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Ramon C Sun
- Department of Biochemistry & Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida, United States
- Department of Biochemistry, University of Florida, Gainesville, Florida, United States
- Center for Advanced Spatial Biomolecule Research, University of Florida, Gainesville, Florida, United States
| | - Lance A Johnson
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States
| | - Warren J Alilain
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
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4
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MacFarlane PM. Inflammation in sudden infant death syndrome. Pediatr Res 2024; 95:885-886. [PMID: 38097722 DOI: 10.1038/s41390-023-02966-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 11/26/2023] [Indexed: 03/09/2024]
Affiliation(s)
- Peter M MacFarlane
- Department of Pediatrics, Division of Neonatology, Rainbow Babies & Children's Hospital, Case Western Reserve University, 2109 Adelbert Rd, Cleveland, OH, 44106, USA.
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5
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Logsdon AF, Erickson MA, Herbert MJ, Noonan C, Foresi BD, Qiu J, Lim YP, Banks WA, Stonestreet BS. Inter-alpha inhibitor proteins attenuate lipopolysaccharide-induced blood-brain barrier disruption in neonatal mice. Exp Neurol 2023; 370:114563. [PMID: 37806514 DOI: 10.1016/j.expneurol.2023.114563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/21/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
There is a paucity of information regarding efficacious pharmacological neuroprotective strategies to attenuate or reduce brain injury in neonates. Lipopolysaccharide (LPS) disrupts blood-brain barrier (BBB) function in adult rodents and increases inflammation in adults and neonates. Human blood-derived Inter-alpha Inhibitor Proteins (IAIPs) are neuroprotective, improve neonatal survival after LPS, and attenuate LPS-induced disruption of the BBB in adult male mice. We hypothesized that LPS also disrupts the function of the BBB in neonatal mice and that IAIPs attenuate the LPS-induced BBB disruption in male and female neonatal mice. IAIPs were administered to neonatal mice after LPS and BBB permeability quantified with intravenous 14C-sucrose and 99mTc-albumin. Although repeated high doses (3 mg/kg) of LPS in neonates resulted in high mortality rates and a robust increase in BBB permeability, repeated lower doses (1 mg/kg) of LPS resulted in lower mortality rates and disruption of the BBB in both male and female neonates. IAIP treatment attenuated disruption of the BBB similarly to sucrose and albumin after exposure to low-dose LPS in neonatal mice. Exposure to low-dose LPS elevated IAIP concentrations in blood, but it did not appear to increase the systemic levels of Pre-alpha inhibitor (PaI), one of the family members of the IAIPs that contains heavy chain 3. We conclude that IAIPs attenuate LPS-related disruption of the BBB in both male and female neonatal mice.
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Affiliation(s)
- Aric F Logsdon
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA.
| | - Michelle A Erickson
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Melanie J Herbert
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Cassidy Noonan
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Brian D Foresi
- College of Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Joseph Qiu
- ProThera Biologics, Inc., Providence, RI 02903, USA
| | - Yow-Pin Lim
- ProThera Biologics, Inc., Providence, RI 02903, USA; Department of Pathology and Laboratory Medicine, The Alpert Medical School of Brown University, Providence, RI, 02905, USA
| | - William A Banks
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Barbara S Stonestreet
- The Alpert Medical School of Brown University, Department of Pediatrics, Women & Infants Hospital of Rhode Island, Providence, RI 02905, USA
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6
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Hedley KE, Callister RJ, Callister R, Horvat JC, Tadros MA. Alterations in brainstem respiratory centers following peripheral inflammation: A systematic review. J Neuroimmunol 2022; 369:577903. [DOI: 10.1016/j.jneuroim.2022.577903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/02/2022] [Accepted: 05/29/2022] [Indexed: 11/29/2022]
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7
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Fukushi I, Takeda K, Pokorski M, Kono Y, Yoshizawa M, Hasebe Y, Nakao A, Mori Y, Onimaru H, Okada Y. Activation of Astrocytes in the Persistence of Post-hypoxic Respiratory Augmentation. Front Physiol 2021; 12:757731. [PMID: 34690820 PMCID: PMC8531090 DOI: 10.3389/fphys.2021.757731] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/15/2021] [Indexed: 11/16/2022] Open
Abstract
Acute hypoxia increases ventilation. After cessation of hypoxia loading, ventilation decreases but remains above the pre-exposure baseline level for a time. However, the mechanism of this post-hypoxic persistent respiratory augmentation (PHRA), which is a short-term potentiation of breathing, has not been elucidated. We aimed to test the hypothesis that astrocytes are involved in PHRA. To this end, we investigated hypoxic ventilatory responses by whole-body plethysmography in unanesthetized adult mice. The animals breathed room air, hypoxic gas mixture (7% O2, 93% N2) for 2min, and again room air for 10min before and after i.p. administration of low (100mg/kg) and high (300mg/kg) doses of arundic acid (AA), an astrocyte inhibitor. AA suppressed PHRA, with the high dose decreasing ventilation below the pre-hypoxic level. Further, we investigated the role of the astrocytic TRPA1 channel, a putative ventilatory hypoxia sensor, in PHRA using astrocyte-specific Trpa1 knockout (asTrpa1−/−) and floxed Trpa1 (Trpa1f/f) mice. In both Trpa1f/f and asTrpa1−/− mice, PHRA was noticeable, indicating that the astrocyte TRPA1 channel was not directly involved in PHRA. Taken together, these results indicate that astrocytes mediate the PHRA by mechanisms other than TRPA1 channels that are engaged in hypoxia sensing.
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Affiliation(s)
- Isato Fukushi
- Faculty of Health Sciences, Uekusa Gakuen University, Chiba, Japan.,Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan
| | - Kotaro Takeda
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan.,Faculty of Rehabilitation, School of Healthcare, Fujita Health University, Toyoake, Japan
| | - Mieczyslaw Pokorski
- Institute of Health Sciences, University of Opole, Opole, Poland.,Faculty of Health Sciences, The Jan Dlugosz University in Czestochowa, Czestochowa, Poland
| | - Yosuke Kono
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan.,Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Masashi Yoshizawa
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan.,Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Yohei Hasebe
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan.,Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Akito Nakao
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan
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8
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Mouradian GC, Lakshminrusimha S, Konduri GG. Perinatal Hypoxemia and Oxygen Sensing. Compr Physiol 2021; 11:1653-1677. [PMID: 33792908 DOI: 10.1002/cphy.c190046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The development of the control of breathing begins in utero and continues postnatally. Fetal breathing movements are needed for establishing connectivity between the lungs and central mechanisms controlling breathing. Maturation of the control of breathing, including the increase of hypoxia chemosensitivity, continues postnatally. Insufficient oxygenation, or hypoxia, is a major stressor that can manifest for different reasons in the fetus and neonate. Though the fetus and neonate have different hypoxia sensing mechanisms and respond differently to acute hypoxia, both responses prevent deviations to respiratory and other developmental processes. Intermittent and chronic hypoxia pose much greater threats to the normal developmental respiratory processes. Gestational intermittent hypoxia, due to maternal sleep-disordered breathing and sleep apnea, increases eupneic breathing and decreases the hypoxic ventilatory response associated with impaired gasping and autoresuscitation postnatally. Chronic fetal hypoxia, due to biologic or environmental (i.e. high-altitude) factors, is implicated in fetal growth restriction and preterm birth causing a decrease in the postnatal hypoxic ventilatory responses with increases in irregular eupneic breathing. Mechanisms driving these changes include delayed chemoreceptor development, catecholaminergic activity, abnormal myelination, increased astrocyte proliferation in the dorsal respiratory group, among others. Long-term high-altitude residents demonstrate favorable adaptations to chronic hypoxia as do their offspring. Neonatal intermittent hypoxia is common among preterm infants due to immature respiratory systems and thus, display a reduced drive to breathe and apneas due to insufficient hypoxic sensitivity. However, ongoing intermittent hypoxia can enhance hypoxic sensitivity causing ventilatory overshoots followed by apnea; the number of apneas is positively correlated with degree of hypoxic sensitivity in preterm infants. Chronic neonatal hypoxia may arise from fetal complications like maternal smoking or from postnatal cardiovascular problems, causing blunting of the hypoxic ventilatory responses throughout at least adolescence due to attenuation of carotid body fibers responses to hypoxia with potential roles of brainstem serotonin, microglia, and inflammation, though these effects depend on the age in which chronic hypoxia initiates. Fetal and neonatal intermittent and chronic hypoxia are implicated in preterm birth and complicate the respiratory system through their direct effects on hypoxia sensing mechanisms and interruptions to the normal developmental processes. Thus, precise regulation of oxygen homeostasis is crucial for normal development of the respiratory control network. © 2021 American Physiological Society. Compr Physiol 11:1653-1677, 2021.
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Affiliation(s)
- Gary C Mouradian
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Satyan Lakshminrusimha
- Department of Pediatrics, UC Davis Children's Hospital, UC Davis Health, UC Davis, Davis, California, USA
| | - Girija G Konduri
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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9
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Mitchell LJ, Mayer CA, Mayer A, Di Fiore JM, Shein SL, Raffay TM, MacFarlane PM. Caffeine prevents prostaglandin E 1-induced disturbances in respiratory control in neonatal rats: implications for infants with critical congenital heart disease. Am J Physiol Regul Integr Comp Physiol 2020; 319:R233-R242. [PMID: 32579854 DOI: 10.1152/ajpregu.00316.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Continuous infusion of prostaglandin E1 (PGE1) is used to maintain ductus arteriosus patency in infants with critical congenital heart disease, but it can also cause central apnea suggesting an effect on respiratory neural control. In this study, we investigated whether 1) PGE1 inhibits the various phases of the acute hypoxic ventilatory response (HVR; an index of respiratory control dysfunction) and increases apnea incidence in neonatal rats; and 2) whether these changes would be reversible with caffeine pretreatment. Whole body plethysmography was used to assess the HVR and apnea incidence in neonatal rats 2 h following a single bolus intraperitoneal injection of PGE1 with and without prior caffeine treatment. Untreated rats exhibited a biphasic HVR characterized by an initial increase in minute ventilation followed by a ventilatory decline of the late phase (~5th minute) of the HVR. PGE1 had a dose-dependent effect on the HVR. Contrary to our hypothesis, the lowest dose (1 µg/kg) of PGE1 prevented the ventilatory decline of the late phase of the HVR. However, PGE1 tended to increase postsigh apnea incidence and the coefficient of variability (CV) of breathing frequency, suggesting increased respiratory instability. PGE1 also decreased brainstem microglia mRNA and increased neuronal nitric oxide synthase (nNOS) and platelet-derived growth factor-β (PDGF-β) gene expression. Caffeine pretreatment prevented these effects of PGE1, and the adenosine A2A receptor inhibitor MSX-3 had similar preventative effects. Prostaglandin appears to have deleterious effects on brainstem respiratory control regions, possibly involving a microglial-dependent mechanism. The compensatory effects of caffeine or MSX-3 treatment raises the question of whether prostaglandin may also operate on an adenosine-dependent pathway.
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Affiliation(s)
- L J Mitchell
- Department of Pediatrics, Division of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio
| | - C A Mayer
- Department of Pediatrics, Division of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio
| | - A Mayer
- Department of Pediatrics, Division of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio
| | - J M Di Fiore
- Department of Pediatrics, Division of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio
| | - S L Shein
- Department of Pediatrics, Division of Pediatric Critical Care, Rainbow Babies and Children's Hospital, Cleveland, Ohio
| | - T M Raffay
- Department of Pediatrics, Division of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio
| | - P M MacFarlane
- Department of Pediatrics, Division of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio
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10
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Mitchell L, MacFarlane PM. Mechanistic actions of oxygen and methylxanthines on respiratory neural control and for the treatment of neonatal apnea. Respir Physiol Neurobiol 2020; 273:103318. [PMID: 31626973 PMCID: PMC6986994 DOI: 10.1016/j.resp.2019.103318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/14/2022]
Abstract
Apnea remains one of the most concerning and prevalent respiratory disorders spanning all ages from infants (particularly those born preterm) to adults. Although the pathophysiological consequences of apnea are fairly well described, the neural mechanisms underlying the etiology of the different types of apnea (central, obstructive, and mixed) still remain incompletely understood. From a developmental perspective, however, research into the respiratory neural control system of immature animals has shed light on both central and peripheral neural pathways underlying apnea of prematurity (AOP), a highly prevalent respiratory disorder of preterm infants. Animal studies have also been fundamental in furthering our understanding of how clinical interventions (e.g. pharmacological and mechanical) exert their beneficial effects in the clinical treatment of apnea. Although current clinical interventions such as supplemental O2 and positive pressure respiratory support are critically important for the infant in respiratory distress, they are not fully effective and can also come with unfortunate, unintended (and long-term) side-effects. In this review, we have chosen AOP as one of the most common clinical scenarios involving apnea to highlight the mechanistic basis behind how some of the interventions could be both beneficial and also deleterious to the respiratory neural control system. We have included a section on infants with critical congenital heart diseases (CCHD), in whom apnea can be a clinical concern due to treatment with prostaglandin, and who may benefit from some of the treatments used for AOP.
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Affiliation(s)
- Lisa Mitchell
- Department of Pediatrics, Case Western Reserve University, Rainbow Babies & Children's Hospital, Cleveland, OH 44106, USA
| | - Peter M MacFarlane
- Department of Pediatrics, Case Western Reserve University, Rainbow Babies & Children's Hospital, Cleveland, OH 44106, USA.
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11
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Effects of inflammation on the developing respiratory system: Focus on hypoglossal (XII) neuron morphology, brainstem neurochemistry, and control of breathing. Respir Physiol Neurobiol 2020; 275:103389. [PMID: 31958568 DOI: 10.1016/j.resp.2020.103389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 01/03/2020] [Accepted: 01/16/2020] [Indexed: 12/20/2022]
Abstract
Breathing is fundamental to life and any adverse change in respiratory function can endanger the health of an organism or even be fatal. Perinatal inflammation is known to adversely affect breathing in preterm babies, but lung infection/inflammation impacts all stages of life from birth to death. Little is known about the role of inflammation in respiratory control, neuronal morphology, or neural function during development. Animal models of inflammation can provide understanding and insight into respiratory development and how inflammatory processes alter developmental phenotype in addition to providing insight into new treatment modalities. In this review, we focus on recent work concerning the development of neurons, models of perinatal inflammation with an emphasis on two common LPS-based models, inflammation and its impact on development, and current and potential treatments for inflammation within the respiratory control circuitry of the mammalian brainstem. We have also discussed models of inflammation in adults and have specifically focused on hypoglossal motoneurons (XII) and neurons of the nucleus tractus solitarii (nTS) as these nuclei have been studied more extensively than other brainstem nuclei participating in breathing and airway control. Understanding the impact of inflammation on the developmental aspects of respiratory control and breathing pattern is critical to addressing problems of cardiorespiratory dysregulation in disease and this overview points out many gaps in our current knowledge.
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12
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Beyeler SA, Hodges MR, Huxtable AG. Impact of inflammation on developing respiratory control networks: rhythm generation, chemoreception and plasticity. Respir Physiol Neurobiol 2020; 274:103357. [PMID: 31899353 DOI: 10.1016/j.resp.2019.103357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/17/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
The respiratory control network in the central nervous system undergoes critical developmental events early in life to ensure adequate breathing at birth. There are at least three "critical windows" in development of respiratory control networks: 1) in utero, 2) newborn (postnatal day 0-4 in rodents), and 3) neonatal (P10-13 in rodents, 2-4 months in humans). During these critical windows, developmental processes required for normal maturation of the respiratory control network occur, thereby increasing vulnerability of the network to insults, such as inflammation. Early life inflammation (induced by LPS, chronic intermittent hypoxia, sustained hypoxia, or neonatal maternal separation) acutely impairs respiratory rhythm generation, chemoreception and increases neonatal risk of mortality. These early life impairments are also greater in young males, suggesting sex-specific impairments in respiratory control. Further, neonatal inflammation has a lasting impact on respiratory control by impairing adult respiratory plasticity. This review focuses on how inflammation alters respiratory rhythm generation, chemoreception and plasticity during each of the three critical windows. We also highlight the need for additional mechanistic studies and increased investigation into how glia (such as microglia and astrocytes) play a role in impaired respiratory control after inflammation. Understanding how inflammation during critical windows of development disrupt respiratory control networks is essential for developing better treatments for vulnerable neonates and preventing adult ventilatory control disorders.
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Affiliation(s)
- Sarah A Beyeler
- Department of Human Physiology, University of Oregon, Eugene, OR, 97403, United States
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - Adrianne G Huxtable
- Department of Human Physiology, University of Oregon, Eugene, OR, 97403, United States.
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13
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Dylag AM, Raffay TM. Rodent models of respiratory control and respiratory system development-Clinical significance. Respir Physiol Neurobiol 2019; 268:103249. [PMID: 31315068 DOI: 10.1016/j.resp.2019.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/24/2019] [Accepted: 06/29/2019] [Indexed: 01/13/2023]
Abstract
The newborn infant's respiratory system must rapidly adapt to extra-uterine life. Neonatal rat and mouse models have been used to investigate early development of respiratory control and reactivity in both health and disease. This review highlights several rodent models of control of breathing and respiratory system development (including pulmonary function), discusses their translational strengths and limitations, and underscores the importance of creating clinically relevant models applicable to the human infant.
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Affiliation(s)
- Andrew M Dylag
- Division of Neonatology, Golisano Children's Hospital, Department of Pediatrics, University of Rochester, Rochester, NY, United States
| | - Thomas M Raffay
- Division of Neonatology, Rainbow Babies & Children's Hospital, Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States.
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14
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Mechanisms underlying a critical period of respiratory development in the rat. Respir Physiol Neurobiol 2019; 264:40-50. [PMID: 30999061 DOI: 10.1016/j.resp.2019.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/05/2019] [Accepted: 04/10/2019] [Indexed: 01/13/2023]
Abstract
Twenty-five years ago, Filiano and Kinney (1994) proposed that a critical period of postnatal development constitutes one of the three risk factors for sudden infant death syndrome (SIDS). The underlying mechanism was poorly understood. In the last 17 years, much has been uncovered on this period in the rat. Against several expected trends of development, abrupt neurochemical, metabolic, ventilatory, and electrophysiological changes occur in the respiratory system at P12-13. This results in a transient synaptic imbalance with suppressed excitation and enhanced inhibition, and the response to acute hypoxia is the weakest at this time, both at the cellular and system's levels. The basis for the synaptic imbalance is likely to be contributed by a reduced expression of brain-derived neurotrophic factor (BDNF) and its TrkB receptors in multiple brain stem respiratory-related nuclei during the critical period. Exogenous BDNF or a TrkB agonist partially reverses the synaptic imbalance, whereas a TrkB antagonist accentuates the imbalance. A transient down-regulation of pituitary adenylate cyclase-activating polypeptide (PACAP) at P12 in respiratory-related nuclei also contributes to the vulnerability of this period. Carotid body denervation during this time or perinatal hyperoxia merely delays and sometimes prolongs, but not eliminate the critical period. The rationale for the necessity of the critical period in postnatal development is discussed.
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15
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Hocker AD, Beyeler SA, Gardner AN, Johnson SM, Watters JJ, Huxtable AG. One bout of neonatal inflammation impairs adult respiratory motor plasticity in male and female rats. eLife 2019; 8:45399. [PMID: 30900989 PMCID: PMC6464604 DOI: 10.7554/elife.45399] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/21/2019] [Indexed: 11/13/2022] Open
Abstract
Neonatal inflammation is common and has lasting consequences for adult health. We investigated the lasting effects of a single bout of neonatal inflammation on adult respiratory control in the form of respiratory motor plasticity induced by acute intermittent hypoxia, which likely compensates and stabilizes breathing during injury or disease and has significant therapeutic potential. Lipopolysaccharide-induced inflammation at postnatal day four induced lasting impairments in two distinct pathways to adult respiratory plasticity in male and female rats. Despite a lack of adult pro-inflammatory gene expression or alterations in glial morphology, one mechanistic pathway to plasticity was restored by acute, adult anti-inflammatory treatment, suggesting ongoing inflammatory signaling after neonatal inflammation. An alternative pathway to plasticity was not restored by anti-inflammatory treatment, but was evoked by exogenous adenosine receptor agonism, suggesting upstream impairment, likely astrocytic-dependent. Thus, the respiratory control network is vulnerable to early-life inflammation, limiting respiratory compensation to adult disease or injury.
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Affiliation(s)
- Austin D Hocker
- Department of Human Physiology, University of Oregon, Eugene, United States
| | - Sarah A Beyeler
- Department of Human Physiology, University of Oregon, Eugene, United States
| | - Alyssa N Gardner
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, United States
| | - Stephen M Johnson
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, United States
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, United States
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16
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Williams PA, Bellinger DL, Wilson CG. Changes in the Morphology of Hypoglossal Motor Neurons in the Brainstem of Developing Rats. Anat Rec (Hoboken) 2018; 302:869-892. [DOI: 10.1002/ar.23971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/08/2018] [Accepted: 04/16/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Paul Allen Williams
- Division of Physiology, Basic Science DepartmentLoma Linda University School of Medicine California Loma Linda
- Lawrence D. Longo MD Center for Perinatal BiologyLoma Linda University School of Medicine Loma Linda California
| | - Denise L. Bellinger
- Division of Physiology, Basic Science DepartmentLoma Linda University School of Medicine California Loma Linda
- Department of Pathology and Human AnatomyLoma Linda University School of Medicine Loma Linda California
| | - Christopher G. Wilson
- Division of Physiology, Basic Science DepartmentLoma Linda University School of Medicine California Loma Linda
- Lawrence D. Longo MD Center for Perinatal BiologyLoma Linda University School of Medicine Loma Linda California
- Department of PediatricsLoma Linda University School of Medicine Loma Linda California
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17
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Peña-Ortega F. Clinical and experimental aspects of breathing modulation by inflammation. Auton Neurosci 2018; 216:72-86. [PMID: 30503161 DOI: 10.1016/j.autneu.2018.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/06/2018] [Accepted: 11/07/2018] [Indexed: 12/19/2022]
Abstract
Neuroinflammation is produced by local or systemic alterations and mediated mainly by glia, affecting the activity of various neural circuits including those involved in breathing rhythm generation and control. Several pathological conditions, such as sudden infant death syndrome, obstructive sleep apnea and asthma exert an inflammatory influence on breathing-related circuits. Consequently breathing (both resting and ventilatory responses to physiological challenges), is affected; e.g., responses to hypoxia and hypercapnia are compromised. Moreover, inflammation can induce long-lasting changes in breathing and affect adaptive plasticity; e.g., hypoxic acclimatization or long-term facilitation. Mediators of the influences of inflammation on breathing are most likely proinflammatory molecules such as cytokines and prostaglandins. The focus of this review is to summarize the available information concerning the modulation of the breathing function by inflammation and the cellular and molecular aspects of this process. I will consider: 1) some clinical and experimental conditions in which inflammation influences breathing; 2) the variety of experimental approaches used to understand this inflammatory modulation; 3) the likely cellular and molecular mechanisms.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, QRO 76230, México.
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Johnson SM, Randhawa KS, Epstein JJ, Gustafson E, Hocker AD, Huxtable AG, Baker TL, Watters JJ. Gestational intermittent hypoxia increases susceptibility to neuroinflammation and alters respiratory motor control in neonatal rats. Respir Physiol Neurobiol 2018; 256:128-142. [PMID: 29174411 PMCID: PMC5963968 DOI: 10.1016/j.resp.2017.11.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/13/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
Abstract
Sleep disordered breathing (SDB) and obstructive sleep apnea (OSA) during pregnancy are growing health concerns because these conditions are associated with adverse outcomes for newborn infants. SDB/OSA during pregnancy exposes the mother and the fetus to intermittent hypoxia. Direct exposure of adults and neonates to IH causes neuroinflammation and neuronal apoptosis, and exposure to IH during gestation (GIH) causes long-term deficits in offspring respiratory function. However, the role of neuroinflammation in CNS respiratory control centers of GIH offspring has not been investigated. Thus, the goal of this hybrid review/research article is to comprehensively review the available literature both in humans and experimental rodent models of SDB in order to highlight key gaps in knowledge. To begin to address some of these gaps, we also include data demonstrating the consequences of GIH on respiratory rhythm generation and neuroinflammation in CNS respiratory control regions. Pregnant rats were exposed to daily intermittent hypoxia during gestation (G10-G21). Neuroinflammation in brainstem and cervical spinal cord was evaluated in P0-P3 pups that were injected with saline or lipopolysaccharide (LPS; 0.1mg/kg, 3h). In CNS respiratory control centers, we found that GIH attenuated the normal CNS immune response to LPS challenge in a gene-, sex-, and CNS region-specific manner. GIH also altered normal respiratory motor responses to LPS in newborn offspring brainstem-spinal cord preparations. These data underscore the need for further study of the long-term consequences of maternal SDB on the relationship between inflammation and the respiratory control system, in both neonatal and adult offspring.
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Affiliation(s)
- Stephen M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States.
| | - Karanbir S Randhawa
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jenna J Epstein
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Ellen Gustafson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Austin D Hocker
- Department of Human Physiology, University of Oregon, Eugene, OR 97401, United States
| | - Adrianne G Huxtable
- Department of Human Physiology, University of Oregon, Eugene, OR 97401, United States
| | - Tracy L Baker
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jyoti J Watters
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
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Porzionato A, Macchi V, De Caro R. Central and peripheral chemoreceptors in sudden infant death syndrome. J Physiol 2018; 596:3007-3019. [PMID: 29645275 PMCID: PMC6068209 DOI: 10.1113/jp274355] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 03/20/2018] [Indexed: 11/08/2022] Open
Abstract
The pathogenesis of sudden infant death syndrome (SIDS) has been ascribed to an underlying biological vulnerability to stressors during a critical period of development. This paper reviews the main data in the literature supporting the role of central (e.g. retrotrapezoid nucleus, serotoninergic raphe nuclei, locus coeruleus, orexinergic neurons, ventral medullary surface, solitary tract nucleus) and peripheral (e.g. carotid body) chemoreceptors in the pathogenesis of SIDS. Clinical and experimental studies indicate that central and peripheral chemoreceptors undergo critical development during the initial postnatal period, consistent with the age range of SIDS (<1 year). Most of the risk factors for SIDS (gender, genetic factors, prematurity, hypoxic/hyperoxic stimuli, inflammation, perinatal exposure to cigarette smoke and/or substance abuse) may structurally and functionally affect the developmental plasticity of central and peripheral chemoreceptors, strongly suggesting the involvement of these structures in the pathogenesis of SIDS. Morphometric and neurochemical changes have been found in the carotid body and brainstem respiratory chemoreceptors of SIDS victims, together with functional signs of chemoreception impairment in some clinical studies. However, the methodological problems of SIDS research will have to be addressed in the future, requiring large and highly standardized case series. Up-to-date autopsy protocols should be produced, involving substantial, and exhaustive sampling of all potentially involved structures (including peripheral arterial chemoreceptors). Morphometric approaches should include unbiased stereological methods with three-dimensional probes. Prospective clinical studies addressing functional tests and risk factors (including genetic traits) would probably be the gold standard, allowing markers of intrinsic or acquired vulnerability to be properly identified.
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Affiliation(s)
- Andrea Porzionato
- Section of Anatomy, Department of NeuroscienceUniversity of PadovaItaly
| | - Veronica Macchi
- Section of Anatomy, Department of NeuroscienceUniversity of PadovaItaly
| | - Raffaele De Caro
- Section of Anatomy, Department of NeuroscienceUniversity of PadovaItaly
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Stryker C, Camperchioli DW, Mayer CA, Alilain WJ, Martin RJ, MacFarlane PM. Respiratory dysfunction following neonatal sustained hypoxia exposure during a critical window of brain stem extracellular matrix formation. Am J Physiol Regul Integr Comp Physiol 2018; 314:R216-R227. [PMID: 29046314 PMCID: PMC5867672 DOI: 10.1152/ajpregu.00199.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 10/05/2017] [Accepted: 10/08/2017] [Indexed: 01/02/2023]
Abstract
The extracellular matrix (ECM) modulates brain maturation and plays a major role in regulating neuronal plasticity during critical periods of development. We examined 1) whether there is a critical postnatal period of ECM expression in brain stem cardiorespiratory control regions and 2) whether the attenuated hypoxic ventilatory response (HVR) following neonatal sustained (5 days) hypoxia [SH (11% O2, 24 h/day)] exposure is associated with altered ECM formation. The nucleus tractus solitarius (nTS), dorsal motor nucleus of the vagus, hypoglossal motor nucleus, cuneate nucleus, and area postrema were immunofluorescently processed for aggrecan and Wisteria floribunda agglutinin (WFA), a key proteoglycan of the ECM and the perineuronal net. From postnatal day ( P) 5 ( P5), aggrecan and WFA expression increased postnatally in all regions. We observed an abrupt increase in aggrecan expression in the nTS, a region that integrates and receives afferent inputs from the carotid body, between P10 and P15 followed by a distinct and transient plateau between P15 and P20. WFA expression in the nTS exhibited an analogous transient plateau, but it occurred earlier (between P10 and P15). SH between P11 and P15 attenuated the HVR (assessed at P16) and increased aggrecan (but not WFA) expression in the nTS, dorsal motor nucleus of the vagus, and area postrema. An intracisternal microinjection of chondroitinase ABC, an enzyme that digests chondroitin sulfate proteoglycans, rescued the HVR and the increased aggrecan expression. These data indicate that important stages of ECM formation take place in key brain stem respiratory neural control regions and appear to be associated with a heightened vulnerability to hypoxia.
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Affiliation(s)
- C. Stryker
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
| | | | - C. A. Mayer
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
| | - W. J. Alilain
- Department of Neurosciences, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - R. J. Martin
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
| | - P. M. MacFarlane
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
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Ribeiro A, Mayer C, Wilson C, Martin R, MacFarlane P. Intratracheal LPS administration attenuates the acute hypoxic ventilatory response: Role of brainstem IL-1β receptors. Respir Physiol Neurobiol 2017; 242:45-51. [DOI: 10.1016/j.resp.2017.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 01/01/2023]
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