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DeRosa H, Smith A, Geist L, Cheng A, Hunter RG, Kentner AC. Maternal immune activation alters placental histone-3 lysine-9 tri-methylation, offspring sensorimotor processing, and hypothalamic transposable element expression in a sex-specific manner. Neurobiol Stress 2023; 24:100538. [PMID: 37139465 PMCID: PMC10149420 DOI: 10.1016/j.ynstr.2023.100538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
Animal models of maternal immune activation (MIA) are central to identifying the biological mechanisms that underly the association between prenatal infection and neuropsychiatric disorder susceptibility. Many studies, however, have limited their scope to protein coding genes and their role in mediating this inherent risk, while much less attention has been directed towards exploring the roles of the epigenome and transposable elements (TEs). In Experiment 1, we demonstrate the ability of MIA to alter the chromatin landscape of the placenta. We induced MIA by injecting 200 μg/kg (i.p.) of lipopolysaccharide (LPS) on gestational day 15 in Sprague-Dawley rats. We found a sex-specific rearrangement of heterochromatin 24-h after exposure to MIA, as evidenced by an increase in histone-3 lysine-9 trimethylation (H3K9me3). In Experiment 2, MIA was associated with long-term sensorimotor processing deficits as indicated by reduced prepulse inhibition (PPI) of the acoustic startle reflex in adult male and female offspring and an increased mechanical allodynia threshold in males. Analyses of gene expression within the hypothalamus-chosen for its involvement in the sex-specific pathogenesis of schizophrenia and the stress response-revealed significantly higher levels of the stress-sensitive genes Gr and Fkbp5. Deleterious TE expression is often a hallmark of neuropsychiatric disease and we found sex-specific increases in the expression of several TEs including IAP, B2 SINE, and LINE-1 ORF1. The data from this study warrant the future consideration of chromatin stability and TEs as part of the mechanism that drives MIA-associated changes in the brain and behavior.
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Affiliation(s)
- Holly DeRosa
- University of Massachusetts Boston, Department of Psychology, Developmental and Brain Sciences Program, Boston, Massachusetts, USA
- School of Arts & Sciences, Health Psychology Program, Massachusetts College of Pharmacy and Health Sciences, Boston, MA, USA
| | - Arianna Smith
- School of Arts & Sciences, Health Psychology Program, Massachusetts College of Pharmacy and Health Sciences, Boston, MA, USA
| | - Laurel Geist
- School of Arts & Sciences, Health Psychology Program, Massachusetts College of Pharmacy and Health Sciences, Boston, MA, USA
| | - Ada Cheng
- School of Arts & Sciences, Health Psychology Program, Massachusetts College of Pharmacy and Health Sciences, Boston, MA, USA
| | - Richard G. Hunter
- University of Massachusetts Boston, Department of Psychology, Developmental and Brain Sciences Program, Boston, Massachusetts, USA
| | - Amanda C. Kentner
- School of Arts & Sciences, Health Psychology Program, Massachusetts College of Pharmacy and Health Sciences, Boston, MA, USA
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2
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Srebro D, Dožić B, Vučković S, Savić Vujović K, Medić Brkić B, Dožić I, Srebro M. The Interactions of Magnesium Sulfate and Cromoglycate in a Rat Model of Orofacial Pain; The Role of Magnesium on Mast Cell Degranulation in Neuroinflammation. Int J Mol Sci 2023; 24:ijms24076241. [PMID: 37047214 PMCID: PMC10094402 DOI: 10.3390/ijms24076241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023] Open
Abstract
Mast cell degranulation impacts the development of pain and inflammation during tissue injury. We investigated the antinociceptive effect of a combination of cromoglycate and magnesium in the orofacial model of pain and the histological profile of the effect of magnesium in orofacial pain. In male Wistar rats, formalin (1.5%, 100 µL) was injected subcutaneously into the right upper lip of rats after cromoglycate and/or magnesium. Pain was measured as the total time spent on pain-related behavior. Toluidine blue staining was used to visualize mast cells under the light microscope. In the formalin test, in phase 1, magnesium antagonized the antinociceptive effect of cromoglycate, while in phase 2, it potentiated or inhibited its effect. Magnesium significantly reduced mast cell degranulation in the acute phase by about 23% and in the second phase by about 40%. Pearson’s coefficient did not show a significant correlation between mast cell degranulation and pain under treatment with magnesium. The cromoglycate–magnesium sulfate combination may prevent the development of inflammatory orofacial pain. The effect of a combination of cromoglycate–magnesium sulfate depends on the nature of the pain and the individual effects of the drugs. Magnesium reduced orofacial inflammation in the periphery, and this effect did not significantly contribute to its analgesic effect.
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Affiliation(s)
- Dragana Srebro
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Branko Dožić
- Department of Pathology, School of Dental Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11000 Belgrade, Serbia
- Correspondence: or
| | - Sonja Vučković
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Katarina Savić Vujović
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Branislava Medić Brkić
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Ivan Dožić
- Department of Biochemistry, School of Dental Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11000 Belgrade, Serbia
| | - Milorad Srebro
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
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3
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Early life inflammation is associated with spinal cord excitability and nociceptive sensitivity in human infants. Nat Commun 2022; 13:3943. [PMID: 35803920 PMCID: PMC9270448 DOI: 10.1038/s41467-022-31505-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 06/16/2022] [Indexed: 11/08/2022] Open
Abstract
Immune function and sensitivity to pain are closely related, but the association between early life inflammation and sensory nervous system development is poorly understood-especially in humans. Here, in term-born infants, we measure brain activity and reflex withdrawal activity (using EEG and EMG) and behavioural and physiological activity (using the PIPP-R score) to assess the impact of suspected early-onset neonatal infection on tactile- and noxious-evoked responses. We present evidence that neonatal inflammation (assessed by measuring C-reactive protein levels) is associated with increased spinal cord excitability and evoked brain activity following both tactile and noxious stimulation. There are early indications that this hyperalgesia could be maintained post-inflammation, supporting pre-clinical reports of early-life immune dysfunction influencing pain sensitivity in adults.
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Wen W, Gong X, Cheung H, Yang Y, Cai M, Zheng J, Tong X, Zhang M. Dexmedetomidine Alleviates Microglia-Induced Spinal Inflammation and Hyperalgesia in Neonatal Rats by Systemic Lipopolysaccharide Exposure. Front Cell Neurosci 2021; 15:725267. [PMID: 34955749 PMCID: PMC8692868 DOI: 10.3389/fncel.2021.725267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/27/2021] [Indexed: 12/24/2022] Open
Abstract
Noxious stimulus and painful experience in early life can induce cognitive deficits and abnormal pain sensitivity. As a major component of the outer membrane of gram-negative bacteria, lipopolysaccharide (LPS) injection mimics clinical symptoms of bacterial infections. Spinal microglial activation and the production of pro-inflammatory cytokines have been implicated in the pathogenesis of LPS-induced hyperalgesia in neonatal rats. Dexmedetomidine (DEX) possesses potent anti-neuroinflammatory and neuroprotective properties through the inhibition of microglial activation and microglial polarization toward pro-inflammatory (M1) phenotype and has been widely used in pediatric clinical practice. However, little is known about the effects of DEX on LPS-induced spinal inflammation and hyperalgesia in neonates. Here, we investigated whether systemic LPS exposure has persistent effects on spinal inflammation and hyperalgesia in neonatal rats and explored the protective role of DEX in adverse effects caused by LPS injection. Systemic LPS injections induced acute mechanical hyperalgesia, increased levels of pro-inflammatory cytokines in serum, and short-term increased expressions of pro-inflammatory cytokines and M1 microglial markers in the spinal cord of neonatal rats. Pretreatment with DEX significantly decreased inflammation and alleviated mechanical hyperalgesia induced by LPS. The inhibition of M1 microglial polarization and microglial pro-inflammatory cytokines expression in the spinal cord may implicate its neuroprotective effect, which highlights a new therapeutic target in the treatment of infection-induced hyperalgesia in neonates and preterm infants.
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Affiliation(s)
- Wen Wen
- Department of Anesthesiology, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xingrui Gong
- Department of Anesthesiology, Xiangyang Central Hospital, Hubei University of Arts and Science, Xiangyang, China
| | - Hoiyin Cheung
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yanyan Yang
- Department of Anesthesiology, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Meihua Cai
- Department of Anesthesiology, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jijian Zheng
- Department of Anesthesiology, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoping Tong
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mazhong Zhang
- Department of Anesthesiology, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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5
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Gomes CI, Barr GA. Local injury and systemic infection in infants alter later nociception and pain affect during early life and adulthood. Brain Behav Immun Health 2021; 9:100175. [PMID: 34589906 PMCID: PMC8474633 DOI: 10.1016/j.bbih.2020.100175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 11/06/2020] [Indexed: 10/25/2022] Open
Abstract
Newborns in intensive care are regularly exposed to minor painful procedures at developmental time points when noxious stimulation would be normally absent. Pain from these interventions is inconsistently treated and often exists concurrently with systemic infection, a common comorbidity of prematurity. Our understanding of the independent and combined effects of early painful experiences and infection on pain response is incomplete. The main goals of this research therefore were to understand how pain and infection experienced early in life influence future nociceptive and affective responses to painful stimuli. Rat pups were infected with E-coli on postnatal day 2 (PN2) and had left hind paw injury with carrageenan on PN3. Standard thermal tests for acute pain, formalin tests for inflammatory pain, and conditioned place aversion testing were performed at different ages to assess the nociceptive and affective components of the pain response. Early E-coli infection and early inflammatory injury with carrageenan both independently increased pain scores following hind paw reinjury with formalin on PN8, with effects persisting into adulthood in the carrageenan exposed group. When experienced concurrently, early E-coli infection and carrageenan exposure also increased conditioned aversion to pain in adults. Effect of sex was significant only in formalin testing, with males showing higher pain scores in infancy and females showing higher pain scores as adults. These findings demonstrate that infection experienced early in life can alter both the nociceptive and affective components of the pain response and that there is a cumulative effect of local and systemic pro-inflammatory processes on the aversive component of pain.
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Affiliation(s)
- Carly I Gomes
- Department of Neonatology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Gordon A Barr
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, 3615 Civic Center Boulevard, Philadelphia, PA, 19104, USA.,Department of Psychology, University of Pennsylvania, 425 S. University Avenue, Stephen A. Levin Building, Philadelphia, PA, USA
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6
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González V, Pelissier T, Cazanga V, Hernández A, Constandil L. Magnesium Salt, a Simple Strategy to Improve Methadone Analgesia in Chronic Pain: An Isobolographic Preclinical Study in Neuropathic Mice. Front Pharmacol 2020; 11:566. [PMID: 32457607 PMCID: PMC7225258 DOI: 10.3389/fphar.2020.00566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 04/14/2020] [Indexed: 11/13/2022] Open
Abstract
Analgesic efficacy of methadone in cancer and chronic non-cancer pains is greater than that of other opioids, probably because of its unique pharmacokinetics properties and also because it targets glutamatergic receptors in addition to µ-opioid receptors. However, methadone has drawbacks which are clearly related to dosing and treatment duration. The authors hypothesized that the antinociceptive efficacy of methadone could be synergistically potentiated by magnesium and copper salts in a preclinical mouse model of chronic pain, using the intraplantar formalin test as algesimetric tool. The spared nerve injury mice model was used to generate mononeuropathy. A low dose (0.25%) formalin was injected in the neuropathic limb in order to give rise only to Phase I response, resulting from direct activation by formalin of nociceptive primary afferents. Licking/biting of the formalin-injected limb was evaluated as nociceptive behavior during a 35-min observation period. Dose-response curves for intraperitoneal magnesium sulfate (10, 30, 100, and 300 mg/kg i.p.), copper sulfate (0.1, 0.3, 1, and 3 mg/kg i.p.) and methadone (0.1, 0.3, 1, and 3 mg/kg i.p.) allowed to combine them in equieffective doses and to determine their interaction by isobolographic analysis. Magnesium sulfate, copper sulfate and methadone dose-dependently decreased the nociceptive response evoked by formalin injection, the respective ED50 being 76.38, 1.18, and 0.50 mg/kg i.p. Isobolographic analysis showed a superadditive interaction for magnesium and methadone. Indeed, despite that both ED50 are obviously equieffective, the ED50 for the MgSO4/methadone combination contained less than one third of the methadone having the ED50 for methadone alone. For the CuSO4/methadone combination, the interaction was only additive. Extrapolated to clinical settings, the results suggest that magnesium salts might be used to improve synergistically the efficacy of methadone in neuropathy, which would allow to reduce the dose of methadone and its associated side effects.
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Affiliation(s)
- Valeria González
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Teresa Pelissier
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Victoria Cazanga
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Alejandro Hernández
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Luis Constandil
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile.,Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
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7
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Karshikoff B, Tadros MA, Mackey S, Zouikr I. Neuroimmune modulation of pain across the developmental spectrum. Curr Opin Behav Sci 2019; 28:85-92. [PMID: 32190717 DOI: 10.1016/j.cobeha.2019.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Today's treatment for chronic pain is inadequate, and novel targets need to be identified. This requires a better understanding of the mechanisms involved in pain sensitization and chronification. In this review, we discuss how peripheral inflammation, as occurs during an infection, modulates the central pain system. In rodents, neonatal inflammation leads to increased pain sensitivity in adulthood by priming immune components both peripherally and centrally. The excitability of neurons in the spinal cord is also altered by neonatal inflammation and may add to pain sensitization later in life. In adult humans, inflammation modulates pain sensitivity as well, partly by affecting the activity in brain areas that process and regulate pain signals. Low-grade inflammation is common in clinical populations both peripherally and centrally, and priming of the immune system has also been suggested in some pain populations. The nociceptive and immune systems are primed by infections and inflammation. The early life programming of nociceptive responses following exposure to infections or inflammation will define individual differences in adult pain perception. Immune-to-brain mechanisms and neuroimmune pathway need further investigation as they may serve both as predictors and therapeutic targets in chronic pain.
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Affiliation(s)
- Bianka Karshikoff
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, USA.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Melissa Anne Tadros
- Faculty of Health and Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - Sean Mackey
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, USA
| | - Ihssane Zouikr
- School of Psychology, The University of Newcastle, Callaghan, NSW, Australia
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Magnúsdóttir EI, Grujic M, Roers A, Hartmann K, Pejler G, Lagerström MC. Mouse mast cells and mast cell proteases do not play a significant role in acute tissue injury pain induced by formalin. Mol Pain 2018; 14:1744806918808161. [PMID: 30280636 PMCID: PMC6247485 DOI: 10.1177/1744806918808161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Subcutaneous formalin injections are used as a model for tissue injury-induced pain where formalin induces pain and inflammation indirectly by crosslinking proteins and directly through activation of the transient receptor potential A1 receptor on primary afferents. Activation of primary afferents leads to both central and peripheral release of neurotransmitters. Mast cells are found in close proximity to peripheral sensory nerve endings and express receptors for neurotransmitters released by the primary afferents, contributing to the neuro/immune interface. Mast cell proteases are found in large quantities within mast cell granules and are released continuously in small amounts and upon mast cell activation. They have a wide repertoire of proposed substrates, including Substance P and calcitonin gene-related peptide, but knowledge of their in vivo function is limited. We evaluated the role of mouse mast cell proteases (mMCPs) in tissue injury pain responses induced by formalin, using transgenic mice lacking either mMCP4, mMCP6, or carboxypeptidase A3 (CPA3), or mast cells in their entirety. Further, we investigated the role of mast cells in heat hypersensitivity following a nerve growth factor injection. No statistical difference was observed between the respective mast cell protease knockout lines and wild-type controls in the formalin test. Mast cell deficiency did not have an effect on formalin-induced nociceptive responses nor nerve growth factor-induced heat hypersensitivity. Our data thus show that mMCP4, mMCP6, and CPA3 as well as mast cells as a whole, do not play a significant role in the pain responses associated with acute tissue injury and inflammation in the formalin test. Our data also indicate that mast cells are not essential to heat hypersensitivity induced by nerve growth factor.
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Affiliation(s)
- Elín I Magnúsdóttir
- 1 Department of Neuroscience, Developmental Genetics Unit, Uppsala University, Uppsala, Sweden
| | - Mirjana Grujic
- 2 Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Axel Roers
- 3 Institute for Immunology, University of Technology Dresden, Dresden, Germany
| | - Karin Hartmann
- 4 Department of Dermatology, University of Luebeck, Luebeck, Germany
| | - Gunnar Pejler
- 2 Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.,5 Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Malin C Lagerström
- 1 Department of Neuroscience, Developmental Genetics Unit, Uppsala University, Uppsala, Sweden
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9
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Tadros MA, Zouikr I, Hodgson DM, Callister RJ. Excitability of Rat Superficial Dorsal Horn Neurons Following a Neonatal Immune Challenge. Front Neurol 2018; 9:743. [PMID: 30245664 PMCID: PMC6137193 DOI: 10.3389/fneur.2018.00743] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/17/2018] [Indexed: 12/15/2022] Open
Abstract
Previous studies have shown that neonatal exposure to a mild inflammatory challenge, such as lipopolysaccharide (LPS, Salmonella enteriditis) results in altered pain behaviors later in life. To further characterize the impact of a neonatal immune challenge on pain processing, we examined the excitability of superficial dorsal horn (SDH) neurons following neonatal LPS exposure and subsequent responses to noxious stimulation at three time-points during early postnatal development. Wistar rats were injected with LPS (0.05 mg/kg i.p.) or saline on postnatal days (PNDs) 3 and 5, and later subjected to the formalin test at PNDs 7, 13, and 22. One hour after formalin injection into the plantar hindpaw, animals were euthanized (Ketamine, 100 mg/kg i.p.) and transverse slices from the lumbosacral spinal cord were prepared. Whole-cell patch-clamp recordings were made from SDH neurons (KCH3SO4-based internal, 22–24°C) on the ipsi- and contralateral sides of the spinal cord. Depolarising current steps were injected into SDH neurons to categorize action potential (AP) discharge. In both saline- and LPS-treated rats we observed age-related increases the percentage of neurons exhibiting tonic-firing, with concurrent decreases in single-spiking, between PND 7 and 22. In contrast, neonatal exposure to LPS failed to alter the proportions of AP discharge patterns at any age examined. We also assessed the subthreshold currents that determine AP discharge in SDH neurons. The rapid outward potassium current, IAr decreased in prevalence with age, but was susceptible to neonatal LPS exposure. Peak IAr current amplitude was greater in ipsilateral vs. contralateral SDH neurons from LPS-treated rats. Spontaneous excitatory synaptic currents (sEPSCs) were recorded to assess network excitability. Age-related increases were observed in sEPSC frequency and time course, but not peak amplitude, in both saline- and LPS-treated rats. Furthermore, sEPSC frequency was higher in ipsilateral vs. contralateral SDH neurons in LPS-treated animals. Taken together, these data suggest a neonatal immune challenge does not markedly affect the intrinsic properties of SDH neurons, however, it can increase the excitability of local spinal cord networks via altering the properties of rapid A-type currents and excitatory synaptic connections. These changes, made in neurons within spinal cord pain circuits, have the capacity to alter nociceptive signaling in the ascending pain pathway.
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Affiliation(s)
- Melissa A Tadros
- Faculty of Health and Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
| | - Ihssane Zouikr
- Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN, Wako, Saitama, Japan
| | - Deborah M Hodgson
- Laboratory of Neuroimmunology, School of Psychology, University of Newcastle, Callaghan, NSW, Australia
| | - Robert J Callister
- Faculty of Health and Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
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10
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Doenni VM, Song CM, Hill MN, Pittman QJ. Early-life inflammation with LPS delays fear extinction in adult rodents. Brain Behav Immun 2017; 63:176-185. [PMID: 27888073 DOI: 10.1016/j.bbi.2016.11.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/10/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022] Open
Abstract
A large body of evidence has been brought forward connecting developmental immune activation to abnormal fear and anxiety levels. Anxiety disorders have extremely high lifetime prevalence, yet susceptibility factors that contribute to their emergence are poorly understood. In this research we investigated whether an inflammatory insult early in life can alter the response to fear conditioning in adulthood. Fear learning and extinction are important and adaptive behaviors, mediated largely by the amygdala and its interconnectivity with cortico-limbic circuits. Male and female rat pups were given LPS (100μg/kg i.p.) or saline at postnatal day 14; LPS activated cFos expression in the central amygdala 2.5h after exposure, but not the basal or lateral nuclei. When tested in adulthood, acquisition of an auditory cued or contextual learned fear memory was largely unaffected as was the extinction of fear to a conditioned context. However, we detected a deficit in auditory fear extinction in male and female rats that experienced early-life inflammation, such that there is a significant delay in fear extinction processes resulting in more sustained fear behaviors in response to a conditioned cue. This response was specific to extinction training and did not persist into extinction recall. The effect could not be explained by differences in pain threshold (unaltered) or in baseline anxiety, which was elevated in adolescent females only and unaltered in adolescent males and adult males and females. This research provides further evidence for the involvement of the immune system during development in the shaping of fear and anxiety related behaviors.
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Affiliation(s)
- V M Doenni
- Hotchkiss Brain Institute, Cumming School of Medicine, Mathison Center for Mental Health, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; Department of Neuroscience, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
| | - C M Song
- Hotchkiss Brain Institute, Cumming School of Medicine, Mathison Center for Mental Health, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - M N Hill
- Hotchkiss Brain Institute, Cumming School of Medicine, Mathison Center for Mental Health, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Q J Pittman
- Hotchkiss Brain Institute, Cumming School of Medicine, Mathison Center for Mental Health, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
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11
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Yan S, Kentner AC. Mechanical allodynia corresponds to Oprm1 downregulation within the descending pain network of male and female rats exposed to neonatal immune challenge. Brain Behav Immun 2017; 63:148-159. [PMID: 27742580 DOI: 10.1016/j.bbi.2016.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/28/2016] [Accepted: 10/10/2016] [Indexed: 12/31/2022] Open
Abstract
Exposure to painful procedures and/or stressors during the early neonatal period can reprogram the underlying neurocircuitry involved in nociception and neuropathic pain perception. The reprogramming of these systems can result in an enduring elevation in sensitivity towards mechanical and thermal stimuli. Recent evidence suggests that exposure to mild inflammatory mediators during the neonatal period can induce similar pain responses in both adolescent and adult rats. Therefore, we sought to profile changes in the expression of several genes across brain areas involved in the active modulation of nociception and neuropathic pain using a well-recognized model of neonatal inflammation. In the present study male and female Sprague-Dawley rats were administered either the inflammatory endotoxin lipopolysaccharide (LPS; 0.05mg/kg, i.p.) or saline (equivolume) on postnatal days (PND) 3 and 5. During adolescence, hind paw mechanical withdrawal thresholds were evaluated using an electronic von Frey anesthesiometer. Animals challenged neonatally with LPS (nLPS) had increased pain sensitivity on this measure which was associated with decreased Oprm1 expression in the prefrontal cortex (PFC) and periaqueductal gray (PAG) of both male and female rats. Although a 'second hit' with LPS in adolescence (aLPS) did not confer protection or reveal additional vulnerabilities, aLPS given to animals treated neonatally with saline was associated with increased pain sensitivity, but only in females. Interestingly, adolescent inflammatory challenge decreased Hcrt2 mRNA in the PAG and elevated Trpv1 in the PAG and PFC of both sexes. There was no effect of inflammatory treatment on either anxiety or depressive-like behavior suggesting that affective functioning did not account for differences in mechanical pain sensitivity. Finally, a preliminary investigation demonstrated that administration of a broad spectrum antibiotic cocktail attenuated the mechanical sensitivity that followed nLPS. Together, these data extend upon evidence that inflammation imparts long term changes in quality of life and pain responses via interference within the descending pain network. Moreover, they highlight a potential window of opportunity to target the microbiota-gut-brain axis and reverse pain processing disturbances following perinatal inflammation.
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Affiliation(s)
- Siyang Yan
- School of Arts & Sciences, Health Psychology Program, MCPHS University (formerly Massachusetts College of Pharmacy & Health Sciences), Boston, MA 02115, United States
| | - Amanda C Kentner
- School of Arts & Sciences, Health Psychology Program, MCPHS University (formerly Massachusetts College of Pharmacy & Health Sciences), Boston, MA 02115, United States.
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12
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Zouikr I, Karshikoff B. Lifetime Modulation of the Pain System via Neuroimmune and Neuroendocrine Interactions. Front Immunol 2017; 8:276. [PMID: 28348566 PMCID: PMC5347117 DOI: 10.3389/fimmu.2017.00276] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/24/2017] [Indexed: 12/12/2022] Open
Abstract
Chronic pain is a debilitating condition that still is challenging both clinicians and researchers. Despite intense research, it is still not clear why some individuals develop chronic pain while others do not or how to heal this disease. In this review, we argue for a multisystem approach to understand chronic pain. Pain is not only to be viewed simply as a result of aberrant neuronal activity but also as a result of adverse early-life experiences that impact an individual's endocrine, immune, and nervous systems and changes which in turn program the pain system. First, we give an overview of the ontogeny of the central nervous system, endocrine, and immune systems and their windows of vulnerability. Thereafter, we summarize human and animal findings from our laboratories and others that point to an important role of the endocrine and immune systems in modulating pain sensitivity. Taking "early-life history" into account, together with the past and current immunological and endocrine status of chronic pain patients, is a necessary step to understand chronic pain pathophysiology and assist clinicians in tailoring the best therapeutic approach.
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Affiliation(s)
- Ihssane Zouikr
- Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN BSI , Wako , Japan
| | - Bianka Karshikoff
- Department of Clinical Neuroscience, Division for Psychology, Karolinska Institutet, Solna, Sweden; Stress Research Institute, Stockholm University, Stockholm, Sweden
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13
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Zouikr I, Bartholomeusz MD, Hodgson DM. Early life programming of pain: focus on neuroimmune to endocrine communication. J Transl Med 2016; 14:123. [PMID: 27154463 PMCID: PMC4859995 DOI: 10.1186/s12967-016-0879-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 04/27/2016] [Indexed: 01/21/2023] Open
Abstract
Chronic pain constitutes a challenge for the scientific community and a significant economic and social cost for modern societies. Given the failure of current drugs to effectively treat chronic pain, which are based on suppressing aberrant neuronal excitability, we propose in this review an integrated approach that views pain not solely originating from neuronal activation but also the result of a complex interaction between the nervous, immune, and endocrine systems. Pain assessment must also extend beyond measures of behavioural responses to noxious stimuli to a more developmentally informed assessment given the significant plasticity of the nociceptive system during the neonatal period. Finally integrating the concept of perinatal programming into the pain management field is a necessary step to develop and target interventions to reduce the suffering associated with chronic pain. We present clinical and animal findings from our laboratory (and others) demonstrating the importance of the microbial and relational environment in programming pain responsiveness later in life via action on hypothalamo-pituitary adrenal (HPA) axis activity, peripheral and central immune system, spinal and supraspinal mechanisms, and the autonomic nervous system.
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Affiliation(s)
- I Zouikr
- Laboratory of Neuroimmunology, School of Psychology, The University of Newcastle, Newcastle, NSW, Australia. .,Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN BSI East Building 4F 409, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - M D Bartholomeusz
- Laboratory of Neuroimmunology, School of Psychology, The University of Newcastle, Newcastle, NSW, Australia
| | - D M Hodgson
- Laboratory of Neuroimmunology, School of Psychology, The University of Newcastle, Newcastle, NSW, Australia
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14
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Pohl CS, Medland JE, Moeser AJ. Early-life stress origins of gastrointestinal disease: animal models, intestinal pathophysiology, and translational implications. Am J Physiol Gastrointest Liver Physiol 2015; 309:G927-41. [PMID: 26451004 PMCID: PMC4683303 DOI: 10.1152/ajpgi.00206.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/01/2015] [Indexed: 01/31/2023]
Abstract
Early-life stress and adversity are major risk factors in the onset and severity of gastrointestinal (GI) disease in humans later in life. The mechanisms by which early-life stress leads to increased GI disease susceptibility in adult life remain poorly understood. Animal models of early-life stress have provided a foundation from which to gain a more fundamental understanding of this important GI disease paradigm. This review focuses on animal models of early-life stress-induced GI disease, with a specific emphasis on translational aspects of each model to specific human GI disease states. Early postnatal development of major GI systems and the consequences of stress on their development are discussed in detail. Relevant translational differences between species and models are highlighted.
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Affiliation(s)
- Calvin S. Pohl
- 1Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan; ,2Gastrointestinal Stress Biology Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan; and
| | - Julia E. Medland
- 3Comparative Biomedical Sciences Program, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Adam J. Moeser
- 1Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan; ,2Gastrointestinal Stress Biology Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan; and
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15
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Woodbury A, Yu SP, Chen D, Gu X, Lee JH, Zhang J, Espinera A, García PS, Wei L. Honokiol for the Treatment of Neonatal Pain and Prevention of Consequent Neurobehavioral Disorders. JOURNAL OF NATURAL PRODUCTS 2015; 78:2531-6. [PMID: 26539813 PMCID: PMC6133305 DOI: 10.1021/acs.jnatprod.5b00225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study examined the short- and long-term neuroprotective and analgesic activity of honokiol (a naturally occurring lignan isolated from Magnolia) on developing brains in neonates exposed to inflammatory pain, known to cause neuronal cell death. Postnatal day 4 (P4) neonatal rat pups were subjected to intraplantar formalin injection to four paws as a model of severe neonatal pain. Intraperitoneal honokiol (10 mg/kg) or corn oil vehicle control was administered 1 h prior to formalin insult, and animals were maintained on honokiol through postnatal day 21 (P21). Behavioral tests for stress and pain were performed after the painful insult, followed by morphological examinations of the brain sections at P7 and P21. Honokiol significantly attenuated acute pain responses 30 min following formalin insult and decreased chronic thermal hyperalgesia later in life. Honokiol-treated rats performed better on tests of exploratory behavior and performed significantly better in tests of memory. Honokiol treatment normalized hippocampal and thalamic c-Fos and hippocampal alveus substance P receptor expression relative to controls at P21. Together, these findings support that (1) neonatal pain experiences predispose rats to the development of chronic behavioral changes and (2) honokiol prevents and reduces both acute and chronic pathological pain-induced deteriorations in neonatal rats.
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Affiliation(s)
- Anna Woodbury
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
- Research Division, Veterans Affairs Medical Center–Atlanta, 1670 Clairmont Road, Decatur, Georgia 30033, United States
| | - Shan Ping Yu
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
- Research Division, Veterans Affairs Medical Center–Atlanta, 1670 Clairmont Road, Decatur, Georgia 30033, United States
| | - Dongdong Chen
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
| | - Xiaohuan Gu
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
| | - Jin Hwan Lee
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
| | - James Zhang
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
| | - Alyssa Espinera
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
| | - Paul S. García
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
- Research Division, Veterans Affairs Medical Center–Atlanta, 1670 Clairmont Road, Decatur, Georgia 30033, United States
| | - Ling Wei
- Department of Anesthesiology, Emory University School of Medicine, 1648 Pierce Drive NE, Atlanta, Georgia 30307, United States
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16
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Campbell EJ, Watters SM, Zouikr I, Hodgson DM, Dayas CV. Recruitment of hypothalamic orexin neurons after formalin injections in adult male rats exposed to a neonatal immune challenge. Front Neurosci 2015; 9:65. [PMID: 25805965 PMCID: PMC4354278 DOI: 10.3389/fnins.2015.00065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 02/16/2015] [Indexed: 11/26/2022] Open
Abstract
Exposure to early life physiological stressors, such as infection, is thought to contribute to the onset of psychopathology in adulthood. In animal models, injections of the bacterial immune challenge, lipopolysaccharide (LPS), during the neonatal period has been shown to alter both neuroendocrine function and behavioral pain responses in adulthood. Interestingly, recent evidence suggests a role for the lateral hypothalamic peptide orexin in stress and nociceptive processing. However, whether neonatal LPS exposure affects the reactivity of the orexin system to formalin-induced inflammatory pain in later life remains to be determined. Male Wistar rats (n = 13) were exposed to either LPS or saline (0.05 mg/kg, i.p) on postnatal days (PND) 3 and 5. On PND 80–97, all rats were exposed to a subcutaneous hindpaw injection of 2.25% formalin. Following behavioral testing, animals were perfused and brains processed for Fos-protein and orexin immunohistochemistry. Rats treated with LPS during the neonatal period exhibited decreased licking behaviors during the interphase of the formalin test, the period typically associated with the active inhibition of pain, and increased grooming responses to formalin in adulthood. Interestingly, these behavioral changes were accompanied by an increase in the percentage of Fos-positive orexin cells in the dorsomedial and perifornical hypothalamus in LPS-exposed animals. Similar increases in Fos-protein were also observed in stress and pain sensitive brain regions that receive orexinergic inputs. These findings highlight a potential role for orexin in the behavioral responses to pain and provide further evidence that early life stress can prime the circuitry responsible for these responses in adulthood.
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Affiliation(s)
- Erin J Campbell
- Neurobiology of Addiction Laboratory, School of Biomedical Sciences and Pharmacy and the Centre for Brain and Mental Health Research, Hunter Medical Research Institute, University of Newcastle Newcastle, NSW, Australia ; Laboratory of Neuroimmunology, School of Psychology, University of Newcastle Newcastle, NSW, Australia
| | - Stephanie M Watters
- Neurobiology of Addiction Laboratory, School of Biomedical Sciences and Pharmacy and the Centre for Brain and Mental Health Research, Hunter Medical Research Institute, University of Newcastle Newcastle, NSW, Australia ; Laboratory of Neuroimmunology, School of Psychology, University of Newcastle Newcastle, NSW, Australia
| | - Ihssane Zouikr
- Laboratory of Neuroimmunology, School of Psychology, University of Newcastle Newcastle, NSW, Australia
| | - Deborah M Hodgson
- Laboratory of Neuroimmunology, School of Psychology, University of Newcastle Newcastle, NSW, Australia
| | - Christopher V Dayas
- Neurobiology of Addiction Laboratory, School of Biomedical Sciences and Pharmacy and the Centre for Brain and Mental Health Research, Hunter Medical Research Institute, University of Newcastle Newcastle, NSW, Australia
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