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Kola G, Clifford CW, Campanaro CK, Dhingra RR, Dutschmann M, Jacono FJ, Dick TE. Peritoneal sepsis caused by Escherichia coli triggers brainstem inflammation and alters the function of sympatho-respiratory control circuits. J Neuroinflammation 2024; 21:45. [PMID: 38331902 PMCID: PMC10854125 DOI: 10.1186/s12974-024-03025-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/19/2024] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND Sepsis has a high mortality rate due to multiple organ failure. However, the influence of peripheral inflammation on brainstem autonomic and respiratory circuits in sepsis is poorly understood. Our working hypothesis is that peripheral inflammation affects central autonomic circuits and consequently contributes to multiorgan failure in sepsis. METHODS In an Escherichia coli (E. coli)-fibrin clot model of peritonitis, we first recorded ventilatory patterns using plethysmography before and 24 h after fibrin clot implantation. To assess whether peritonitis was associated with brainstem neuro-inflammation, we measured cytokine and chemokine levels in Luminex assays. To determine the effect of E. coli peritonitis on brainstem function, we assessed sympatho-respiratory nerve activities at baseline and during brief (20 s) hypoxemic ischemia challenges using in situ-perfused brainstem preparations (PBPs) from sham or infected rats. PBPs lack peripheral organs and blood, but generate vascular tone and in vivo rhythmic activities in thoracic sympathetic (tSNA), phrenic and vagal nerves. RESULTS Respiratory frequency was greater (p < 0.001) at 24 h post-infection with E. coli than in the sham control. However, breath-by-breath variability and total protein in the BALF did not differ. IL-1β (p < 0.05), IL-6 (p < 0.05) and IL-17 (p < 0.04) concentrations were greater in the brainstem of infected rats. In the PBP, integrated tSNA (p < 0.05) and perfusion pressure were greater (p < 0.001), indicating a neural-mediated pathophysiological high sympathetic drive. Moreover, respiratory frequency was greater (p < 0.001) in PBPs from infected rats than from sham rats. Normalized phase durations of inspiration and expiration were greater (p < 0.009, p < 0.015, respectively), but the post-inspiratory phase (p < 0.007) and the breath-by-breath variability (p < 0.001) were less compared to sham PBPs. Hypoxemic ischemia triggered a biphasic response, respiratory augmentation followed by depression. PBPs from infected rats had weaker respiratory augmentation (p < 0.001) and depression (p < 0.001) than PBPs from sham rats. In contrast, tSNA in E. coli-treated PBPs was enhanced throughout the entire response to hypoxemic ischemia (p < 0.01), consistent with sympathetic hyperactivity. CONCLUSION We show that peripheral sepsis caused brainstem inflammation and impaired sympatho-respiratory motor control in a single day after infection. We conclude that central sympathetic hyperactivity may impact vital organ systems in sepsis.
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Affiliation(s)
- Gjinovefa Kola
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Caitlyn W Clifford
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Cara K Campanaro
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Rishi R Dhingra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Mathias Dutschmann
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, 44106, USA
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA.
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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Vecchiarelli HA, Lopes LT, Paolicelli RC, Stevens B, Wake H, Tremblay MÈ. Synapse Regulation. ADVANCES IN NEUROBIOLOGY 2024; 37:179-208. [PMID: 39207693 DOI: 10.1007/978-3-031-55529-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Microglia are the resident immune cells of the brain. As such, they rapidly detect changes in normal brain homeostasis and accurately respond by fine-tuning in a tightly regulated manner their morphology, gene expression, and functional behavior. Depending on the nature of these changes, microglia can thicken and retract their processes, proliferate and migrate, release numerous signaling factors and compounds influencing neuronal physiology (e.g., cytokines and trophic factors), in addition to secreting proteases able to transform the extracellular matrix, and phagocytosing various types of cellular debris, etc. Because microglia also transform rapidly (on a time scale of minutes) during experimental procedures, studying these very special cells requires methods that are specifically non-invasive. The development of such methods has provided unprecedented insights into the roles of microglia during normal physiological conditions. In particular, transcranial two-photon in vivo imaging revealed that presumably "resting" microglia continuously survey the brain parenchyma with their highly motile processes, in addition to modulating their structural and functional interactions with neuronal circuits along the changes in neuronal activity and behavioral experience occurring throughout the lifespan. In this chapter, we will describe how surveillant microglia interact with synaptic elements and modulate the number, maturation, function, and plasticity of synapses in the healthy developing, mature, and aging brain, with consequences on neuronal activity, learning and memory, and the behavioral outcome.
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Affiliation(s)
| | | | - Rosa C Paolicelli
- Division of Psychiatry Research, University of Zurich, Schlieren, Switzerland
| | - Beth Stevens
- Department of Neurology, Harvard Medical School, Center for Life Science, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, USA
| | - Hiroaki Wake
- Division of Brain Circuits, National Institute for Basic Biology, Myodaiji-cho, Okazaki, Japan
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
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Campanaro CK, Nethery DE, Guo F, Kaffashi F, Loparo KA, Jacono FJ, Dick TE, Hsieh YH. Dynamics of ventilatory pattern variability and Cardioventilatory Coupling during systemic inflammation in rats. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1038531. [PMID: 37583625 PMCID: PMC10423997 DOI: 10.3389/fnetp.2023.1038531] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 06/20/2023] [Indexed: 08/17/2023]
Abstract
Introduction: Biometrics of common physiologic signals can reflect health status. We have developed analytics to measure the predictability of ventilatory pattern variability (VPV, Nonlinear Complexity Index (NLCI) that quantifies the predictability of a continuous waveform associated with inhalation and exhalation) and the cardioventilatory coupling (CVC, the tendency of the last heartbeat in expiration to occur at preferred latency before the next inspiration). We hypothesized that measures of VPV and CVC are sensitive to the development of endotoxemia, which evoke neuroinflammation. Methods: We implanted Sprague Dawley male rats with BP transducers to monitor arterial blood pressure (BP) and recorded ventilatory waveforms and BP simultaneously using whole-body plethysmography in conjunction with BP transducer receivers. After baseline (BSLN) recordings, we injected lipopolysaccharide (LPS, n = 8) or phosphate buffered saline (PBS, n =3) intraperitoneally on 3 consecutive days. We recorded for 4-6 h after the injection, chose 3 epochs from each hour and analyzed VPV and CVC as well as heart rate variability (HRV). Results: First, the responses to sepsis varied across rats, but within rats the repeated measures of NLCI, CVC, as well as respiratory frequency (fR), HR, BP and HRV had a low coefficient of variation, (<0.2) at each time point. Second, HR, fR, and NLCI increased from BSLN on Days 1-3; whereas CVC decreased on Days 2 and 3. In contrast, changes in BP and the relative low-(LF) and high-frequency (HF) of HRV were not significant. The coefficient of variation decreased from BSLN to Day 3, except for CVC. Interestingly, NLCI increased before fR in LPS-treated rats. Finally, we histologically confirmed lung injury, systemic inflammation via ELISA and the presence of the proinflammatory cytokine, IL-1β, with immunohistochemistry in the ponto-medullary respiratory nuclei. Discussion: Our findings support that NLCI reflects changes in the rat's health induced by systemic injection of LPS and reflected in increases in HR and fR. CVC decreased over the course to the experiment. We conclude that NLCI reflected the increase in predictability of the ventilatory waveform and (together with our previous work) may reflect action of inflammatory cytokines on the network generating respiration.
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Affiliation(s)
- Cara K. Campanaro
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - David E. Nethery
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Fei Guo
- Institute for Smart, Secure and Connected Systems (ISSACS), Case Western Reserve University, Cleveland, OH, United States
| | - Farhad Kaffashi
- Institute for Smart, Secure and Connected Systems (ISSACS), Case Western Reserve University, Cleveland, OH, United States
| | - Kenneth A. Loparo
- Institute for Smart, Secure and Connected Systems (ISSACS), Case Western Reserve University, Cleveland, OH, United States
| | - Frank J. Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Thomas E. Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
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Horton KKA, Campanaro CK, Clifford C, Nethery DE, Strohl KP, Jacono FJ, Dick TE. Cannabinoid Receptor mRNA Expression in Central and Peripheral Tissues in a Rodent Model of Peritonitis. Cannabis Cannabinoid Res 2023; 8:510-526. [PMID: 35446129 PMCID: PMC10249742 DOI: 10.1089/can.2021.0085] [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] [Indexed: 11/13/2022] Open
Abstract
Introduction: Our laboratory investigates changes in the respiratory pattern during systemic inflammation in various rodent models. The endogenous cannabinoid system (ECS) regulates cytokine production and mitigates inflammation. Inflammation not only affects cannabinoid (CB) 1 and CB2 receptor gene expression (Cnr1 and Cnr2), but also increases the predictability of the ventilatory pattern. Objectives: Our primary objective was to track ventilatory pattern variability and transcription of Cnr1 and Cnr2 mRNA, and of Il1b, Il6, and tumor necrosis factor-alpha (Tnfa) mRNAs at multiple time points in central and peripheral tissues during systemic inflammation induced by peritonitis. Methods: In male Sprague Dawley rats (n=24), we caused peritonitis by implanting a fibrin clot containing either 0 or 25×106 Escherichia coli intraperitoneally. We recorded breathing with whole-animal plethysmography at baseline and 1 h before euthanasia. We euthanized the rats at 3, 6, or 12 h after inoculation and harvested the pons, medulla, lung, and heart for gene expression analysis. Results: With peritonitis, Cnr1 mRNA more than Cnr2 mRNA was correlated to Il1b, Il6, and Tnfa mRNAs in medulla, pons, and lung and changed oppositely in the pons, medulla, and lung. These changes were associated with increased predictability of ventilatory pattern. Specifically, nonlinear complexity index correlated with increased Cnr1 mRNA in the pons and medulla, and coefficient of variation for cycle duration correlated with Cnr1 and Cnr2 mRNAs in the lung. Conclusion: The mRNAs for ECS receptors varied with time during the central and peripheral inflammatory response to peritonitis. These changes occurred in the brainstem, which contains the network that generates breathing pattern and thus, may participate in ventilatory pattern changes during systemic inflammation.
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Affiliation(s)
- Kofi-Kermit A. Horton
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Cara K. Campanaro
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Caitlyn Clifford
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - David E. Nethery
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Kingman P. Strohl
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA
| | - Frank J. Jacono
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA
| | - Thomas E. Dick
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA
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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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Chaddha A, Broytman O, Teodorescu M. Effects of allergic airway inflammation and chronic intermittent hypoxia on systemic blood pressure. Am J Physiol Regul Integr Comp Physiol 2020; 319:R566-R574. [PMID: 32903041 DOI: 10.1152/ajpregu.00325.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Asthma and obstructive sleep apnea (OSA) are highly prevalent chronic conditions, and both are associated with systemic hypertension. Additionally, asthma and OSA reciprocally interact, mutually exacerbating each other. In this study, we tested the effect of allergen-induced lower airway inflammation and concurrent chronic intermittent hypoxia (CIH) on systemic blood pressure (BP), pulmonary function, and proinflammatory cytokines, in a rat model. Brown Norway rats were exposed to 43 days of normoxia (NORM) or CIH, concurrent with weekly house dust mite (HDM) challenges. BP was measured 1 day after the last HDM challenge. On day 44, pulmonary function was tested, and blood for Th-2 and Th-1 cytokine levels was collected. HDM significantly increased mean (P = 0.002), systolic (P = 0.003), and diastolic (P = 0.004) BP compared with saline-challenged controls. Higher mean BP significantly correlated to increased total respiratory system resistance (R2 = 0.266, P = 0.002), driven by an association with parenchymal tissue dampening (R2 = 0.166, P = 0.016). HDM relative to saline-challenged controls increased the expression of serum IL-6 (P = 0.008), but no relationships of systemic BP with IL-6 or any other cytokines were found. CIH did not alter the allergen-induced responses on BP, although it tended to increase the expression of serum IL-6 (P = 0.06) and monocyte chemoattractant protein-1 (MCP-1, P = 0.09), regardless of HDM challenge. Chronic allergen-induced airway inflammation results in systemic hypertension that is correlated to the degree of distal airway obstruction induced by the allergen. These effects do not appear to be explained by the associated systemic inflammation.
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Affiliation(s)
- Ashish Chaddha
- Department of Medicine, University of Wisconsin, Madison, Wisconsin
| | - Oleg Broytman
- Department of Medicine, University of Wisconsin, Madison, Wisconsin.,William S. Middleton Memorial Veterans Affairs Medical Center, Madison, Wisconsin
| | - Mihaela Teodorescu
- Department of Medicine, University of Wisconsin, Madison, Wisconsin.,William S. Middleton Memorial Veterans Affairs Medical Center, Madison, Wisconsin
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Litvin DG, Denstaedt SJ, Borkowski LF, Nichols NL, Dick TE, Smith CB, Jacono FJ. Peripheral-to-central immune communication at the area postrema glial-barrier following bleomycin-induced sterile lung injury in adult rats. Brain Behav Immun 2020; 87:610-633. [PMID: 32097765 PMCID: PMC8895345 DOI: 10.1016/j.bbi.2020.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/02/2020] [Accepted: 02/13/2020] [Indexed: 02/07/2023] Open
Abstract
The pathways for peripheral-to-central immune communication (P → C I-comm) following sterile lung injury (SLI) are unknown. SLI evokes systemic and central inflammation, which alters central respiratory control and viscerosensory transmission in the nucleus tractus solitarii (nTS). These functional changes coincide with increased interleukin-1 beta (IL-1β) in the area postrema, a sensory circumventricular organ that connects P → C I-comm to brainstem circuits that control homeostasis. We hypothesize that IL-1β and its downstream transcriptional target, cyclooxygenase-2 (COX-2), mediate P → C I-comm in the nTS. In a rodent model of SLI induced by intratracheal bleomycin (Bleo), the sigh frequency and duration of post-sigh apnea increased in Bleo- compared to saline- treated rats one week after injury. This SLI-dependent change in respiratory control occurred concurrently with augmented IL-1β and COX-2 immunoreactivity (IR) in the funiculus separans (FS), a barrier between the AP and the brainstem. At this barrier, increases in IL-1β and COX-2 IR were confined to processes that stained for glial fibrillary acidic protein (GFAP) and that projected basolaterally to the nTS. Further, FS radial-glia did not express TNF-α or IL-6 following SLI. To test our hypothesis, we blocked central COX-1/2 activity by intracerebroventricular (ICV) infusion of Indomethacin (Ind). Continuous ICV Ind treatment prevented Bleo-dependent increases in GFAP + and IL-1β + IR, and restored characteristics of sighs that reset the rhythm. These data indicate that changes in sighs following SLI depend partially on activation of a central COX-dependent P → C I-comm via radial-glia of the FS.
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Affiliation(s)
- David G Litvin
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
| | - Scott J Denstaedt
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lauren F Borkowski
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Nicole L Nichols
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Corey B Smith
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
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Hsieh YH, Litvin DG, Zaylor AR, Nethery DE, Dick TE, Jacono FJ. Brainstem inflammation modulates the ventilatory pattern and its variability after acute lung injury in rodents. J Physiol 2020; 598:2791-2811. [PMID: 32378188 DOI: 10.1113/jp279177] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 04/21/2020] [Indexed: 01/20/2023] Open
Abstract
KEY POINTS Compared with sham rats, rats a week after acute lung injury (ALI) express more pro-inflammatory cytokines in their brainstem respiratory control nuclei, exhibit a higher respiratory frequency (fR) and breathe with a more predictable pattern. These characteristics of the respiratory pattern persist in in situ preparations even after minimizing pulmonary and chemo-afferent inputs. Interleukin (IL)-1β microinjected in the nucleus tractus solitarii increases fR and the predictability of the ventilatory pattern similar to rats with ALI. Intracerebroventricular infusion of indomethacin, an anti-inflammatory drug, mitigates the effect of ALI on fR and ventilatory pattern variability. We conclude that changes in the ventilatory pattern after ALI result not only from sensory input due to pulmonary damage and dysfunction but also from neuro-inflammation. ABSTRACT Acute lung injury (ALI) increases respiratory rate (fR) and ventilatory pattern variability (VPV), but also evokes peripheral and central inflammation. We hypothesized that central inflammation has a role in determining the ventilatory pattern after ALI. In rat pups, we intratracheally injected either bleomycin to induce ALI or saline as a sham control. One week later, we recorded the ventilatory pattern of the rat pups using flow-through plethysmography, then formed in situ preparations from these pups and recorded their 'fictive' patterns from respiratory motor nerves. Compared with the ventilatory pattern of the sham rat pups, injured rat pups had increased fR and predictability. Surprisingly, the fictive patterns of the in situ preparations from ALI pups retained these characteristics despite removing their lungs to eliminate pulmonary sensory inputs and perfusing them with hyperoxic artificial cerebral spinal fluid to minimize peripheral chemoreceptor input. Histological processing revealed increased immunoreactivity of the pro-inflammatory cytokine Interleukin-1β (IL-1β) in the nucleus tractus solitarii (nTS) from ALI but not sham rats. In subsequent experiments, we microinjected IL-1β in the nTS bilaterally in anaesthetized naïve adult rats, which increased fR and predictability of ventilatory pattern variability (VPV) after 2 h. Finally, we infused indomethacin intracerebroventricularly during the week of survival after ALI. This did not affect sham rats, but mitigated changes in fR and VPV in ALI rats. We conclude that neuro-inflammation has an essential role in determining the ventilatory pattern of ALI rats.
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Affiliation(s)
- Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - David G Litvin
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States.,Department of Fundamental Neuroscience, University of Lausanne, Lausanne, 1005, Switzerland
| | - Abigail R Zaylor
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, Ohio, United States.,Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, Ohio, United States
| | - David E Nethery
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, Ohio, United States.,Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, Ohio, United States.,Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, Ohio, United States
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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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Rackley CR, MacIntyre NR. Low Tidal Volumes for Everyone? Chest 2019; 156:783-791. [DOI: 10.1016/j.chest.2019.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/13/2019] [Accepted: 06/06/2019] [Indexed: 01/03/2023] Open
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Getsy PM, Mayer CA, MacFarlane PM, Jacono FJ, Wilson CG. Acute lung injury in neonatal rats causes postsynaptic depression in nucleus tractus solitarii second-order neurons. Respir Physiol Neurobiol 2019; 269:103250. [PMID: 31352011 DOI: 10.1016/j.resp.2019.103250] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/14/2019] [Accepted: 07/02/2019] [Indexed: 12/28/2022]
Abstract
Acute Lung Injury (ALI) alters pulmonary reflex responses, in part due to changes in modulation within the lung and airway neuronal control networks. We hypothesized that synaptic efficacy of nucleus tractus solitarii (nTS) neurons, receiving input from lung, airway, and other viscerosensory afferent fibers, would decrease following ALI. Sprague Dawley neonatal rats (postnatal days 9-11) were given intratracheal installations of saline or bleomycin (a well-characterized model that reproduces the pattern of ALI) and then, one week later, in vitro slices were prepared for whole-cell and perforated whole-cell patch-clamp experiments (postnatal days 16-21). In preparations from ALI rats, 2nd-order nTS neurons had significantly decreased amplitudes of both spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs), compared to saline controls. Rise and decay times of sEPSCs were slower in whole-cell recordings from ALI animals. Similarly, the amplitude of tractus solitarii evoked EPSCs (TS-eEPSCs) were significantly lower in 2nd-order nTS neurons from ALI rats. Overall these results suggest the presence of postsynaptic depression at TS-nTS synapses receiving lung, airway, and other viscerosensory afferent tractus solitarii input after bleomycin-induced ALI.
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Affiliation(s)
- Paulina M Getsy
- Department of Physiology and Biophysics, CWRU School of Medicine, Cleveland, OH, 44106, United States; Department of Pediatrics, Rainbow Babies & Children's Hospital, CWRU School of Medicine, Cleveland, OH, 44106, United States
| | - Catherine A Mayer
- Department of Pediatrics, Rainbow Babies & Children's Hospital, CWRU School of Medicine, Cleveland, OH, 44106, United States
| | - Peter M MacFarlane
- Department of Pediatrics, Rainbow Babies & Children's Hospital, CWRU School of Medicine, Cleveland, OH, 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, CWRU School of Medicine, Cleveland, OH, 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH, 44106, United States
| | - Christopher G Wilson
- Department of Pediatrics and Lawrence D. Long, MD Center for Perinatal Biology Loma Linda University Loma Linda, CA, United States.
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Young BP, Loparo KA, Dick TE, Jacono FJ. Ventilatory pattern variability as a biometric for severity of acute lung injury in rats. Respir Physiol Neurobiol 2019; 265:161-171. [PMID: 30928542 PMCID: PMC9994622 DOI: 10.1016/j.resp.2019.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 03/05/2019] [Accepted: 03/26/2019] [Indexed: 01/27/2023]
Abstract
We hypothesize that ventilatory pattern variability (VPV) varies with the magnitude of acute lung injury (ALI). In adult male rats, we instilled a low- or high- dose of bleomycin or saline (PBS) intratracheally. While representative samples of pulmonary tissue indicated graded lung injury, coefficient of variation (CV) of TTOT did not differ among the 3 groups. Broncho-alveolar lavage fluid (BALF), respiratory rate (fR), mutual information were greater in ALI than sham rats; but did not differ between bleomycin doses. However, nonlinear complexity index (NLCI), which is the difference in sample entropy between original and surrogate data sets was greater for high- versus low- dose; but did not differ between low-dose and sham groups. Further, NLCI correlated to an injury index based on protein concentration of BALF and failure to gain weight. Finally, Receiver Operator Curves (ROCs) indicated that both mutual information and NLCI had greater sensitivity and specificity than fR and CVTTOT in identifying ALI. Thus, nonlinear analyses of VPV can distinguish ALI and out performs fR as a biometric.
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Affiliation(s)
- Benjamin P Young
- Division of Pulmonary, Critical Care, & Sleep Medicine, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kenneth A Loparo
- Department of Electrical Engineering and Computer Science, School of Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Thomas E Dick
- Division of Pulmonary, Critical Care, & Sleep Medicine, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Neurosciences, School of Medicine Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Frank J Jacono
- Division of Pulmonary, Critical Care, & Sleep Medicine, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, USA
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13
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Lima-Silveira L, Accorsi-Mendonça D, Bonagamba LGH, Almado CEL, da Silva MP, Nedoboy PE, Pilowsky PM, Machado BH. Enhancement of excitatory transmission in NTS neurons projecting to ventral medulla of rats exposed to sustained hypoxia is blunted by minocycline. J Physiol 2019; 597:2903-2923. [PMID: 30993693 DOI: 10.1113/jp277532] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 04/16/2019] [Indexed: 01/13/2023] Open
Abstract
KEY POINTS Rats subjected to sustained hypoxia (SH) present increases in arterial pressure (AP) and in glutamatergic transmission in the nucleus tractus solitarius (NTS) neurons sending projections to ventrolateral medulla (VLM). Treatment with minocycline, a microglial inhibitor, attenuated the increase in AP in response to SH. The increase in the amplitude of glutamatergic postsynaptic currents in the NTS-VLM neurons, induced by postsynaptic mechanisms, was blunted by minocycline treatment. The number of microglial cells was increased in the NTS of vehicle-treated SH rats but not in the NTS of minocycline-treated rats. The data show that microglial recruitment/proliferation induced by SH is associated with the enhancement of excitatory neurotransmission in NTS-VLM neurons, which may contribute to the observed increase in AP. ABSTRACT Short-term sustained hypoxia (SH) produces significant autonomic and respiratory adjustments and triggers activation of microglia, the resident immune cells in the brain. SH also enhances glutamatergic neurotransmission in the NTS. Here we evaluated the role of microglial activation induced by SH on the cardiovascular changes and mainly on glutamatergic neurotransmission in NTS neurons sending projections to the ventrolateral medulla (NTS-VLM), using a microglia inhibitor (minocycline). Direct measurement of arterial pressure (AP) in freely moving rats showed that SH (24 h, fraction of inspired oxygen ( F I , O 2 ) 0.1) in vehicle and minocycline (30 mg/kg i.p. for 3 days)-treated groups produced a significant increase in AP in relation to control groups under normoxic conditions, but this increase was significantly lower in minocycline-treated rats. Whole-cell patch-clamp recordings revealed that the active properties of the membrane were comparable among the groups. Nevertheless, the amplitudes of glutamatergic postsynaptic currents, evoked by tractus solitarius stimulation, were increased in NTS-VLM neurons of SH rats. Changes in asynchronous glutamatergic currents indicated that the observed increase in amplitude was due to postsynaptic mechanisms. These changes were blunted in the SH group previously treated with minocycline. Using immunofluorescence, we found that the number of microglial cells was increased in the NTS of vehicle-treated SH rats but not in the NTS neurons of minocycline-treated rats. Our data support the concept that microglial activation induced by SH is associated with the enhancement of excitatory neurotransmission in NTS-VLM neurons, which may contribute to the increase in AP observed in this experimental model.
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Affiliation(s)
- Ludmila Lima-Silveira
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
| | - Daniela Accorsi-Mendonça
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
| | - Leni G H Bonagamba
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
| | - Carlos Eduardo L Almado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
| | - Melina P da Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
| | - Polina E Nedoboy
- The Heart Research Institute, Sydney, New South Wales, 2042, Australia
| | - Paul M Pilowsky
- The Heart Research Institute, Sydney, New South Wales, 2042, Australia
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
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