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Hoffet MS, Tomov NS, Hupp S, Mitchell TJ, Iliev AI. Glucose and Oxygen Levels Modulate the Pore-Forming Effects of Cholesterol-Dependent Cytolysin Pneumolysin from Streptococcus pneumoniae. Toxins (Basel) 2024; 16:232. [PMID: 38922127 PMCID: PMC11209487 DOI: 10.3390/toxins16060232] [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: 03/08/2024] [Revised: 05/08/2024] [Accepted: 05/16/2024] [Indexed: 06/27/2024] Open
Abstract
A major Streptococcus pneumoniae pathogenic factor is the cholesterol-dependent cytolysin pneumolysin, binding membrane cholesterol and producing permanent lytic or transient pores. During brain infections, vascular damage with variable ischemia occurs. The role of ischemia on pneumolysin's pore-forming capacity remains unknown. In acute brain slice cultures and primary cultured glia, we studied acute toxin lysis (via propidium iodide staining and LDH release) and transient pore formation (by analyzing increases in the intracellular calcium). We analyzed normal peripheral tissue glucose conditions (80 mg%), normal brain glucose levels (20 mg%), and brain hypoglycemic conditions (3 mg%), in combinations either with normoxia (8% oxygen) or hypoxia (2% oxygen). At 80 mg% glucose, hypoxia enhanced cytolysis via pneumolysin. At 20 mg% glucose, hypoxia did not affect cell lysis, but impaired calcium restoration after non-lytic pore formation. Only at 3 mg% glucose, during normoxia, did pneumolysin produce stronger lysis. In hypoglycemic (3 mg% glucose) conditions, pneumolysin caused a milder calcium increase, but restoration was missing. Microglia bound more pneumolysin than astrocytes and demonstrated generally stronger calcium elevation. Thus, our work demonstrated that the toxin pore-forming capacity in cells continuously diminishes when oxygen is reduced, overlapping with a continuously reduced ability of cells to maintain homeostasis of the calcium influx once oxygen and glucose are reduced.
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Affiliation(s)
- Michelle Salomé Hoffet
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
| | - Nikola S. Tomov
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
| | - Sabrina Hupp
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
| | - Timothy J. Mitchell
- School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK;
| | - Asparouh I. Iliev
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
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Hirose K, Li SZ, Gill R, Hartsock J. Pneumococcal Meningitis Induces Hearing Loss and Cochlear Ossification Modulated by Chemokine Receptors CX3CR1 and CCR2. J Assoc Res Otolaryngol 2024; 25:179-199. [PMID: 38472515 PMCID: PMC11018586 DOI: 10.1007/s10162-024-00935-4] [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: 09/07/2023] [Accepted: 01/12/2024] [Indexed: 03/14/2024] Open
Abstract
PURPOSE Pneumococcal meningitis is a major cause of hearing loss and permanent neurological impairment despite widely available antimicrobial therapies to control infection. Methods to improve hearing outcomes for those who survive bacterial meningitis remains elusive. We used a mouse model of pneumococcal meningitis to evaluate the impact of mononuclear phagocytes on hearing outcomes and cochlear ossification by altering the expression of CX3CR1 and CCR2 in these infected mice. METHODS We induced pneumococcal meningitis in approximately 500 C57Bl6 adult mice using live Streptococcus pneumoniae (serotype 3, 1 × 105 colony forming units (cfu) in 10 µl) injected directly into the cisterna magna of anesthetized mice and treated these mice with ceftriaxone daily until recovered. We evaluated hearing thresholds over time, characterized the cochlear inflammatory response, and quantified the amount of new bone formation during meningitis recovery. We used microcomputed tomography (microCT) scans to quantify cochlear volume loss caused by neo-ossification. We also performed perilymph sampling in live mice to assess the integrity of the blood-perilymph barrier during various time intervals after meningitis. We then evaluated the effect of CX3CR1 or CCR2 deletion in meningitis symptoms, hearing loss, macrophage/monocyte recruitment, neo-ossification, and blood labyrinth barrier function. RESULTS Sixty percent of mice with pneumococcal meningitis developed hearing loss. Cochlear fibrosis could be detected within 4 days of infection, and neo-ossification by 14 days. Loss of spiral ganglion neurons was common, and inner ear anatomy was distorted by scarring caused by new soft tissue and bone deposited within the scalae. The blood-perilymph barrier was disrupted at 3 days post infection (DPI) and was restored by seven DPI. Both CCR2 and CX3CR1 monocytes and macrophages were present in the cochlea in large numbers after infection. Neither chemokine receptor was necessary for the induction of hearing loss, cochlear fibrosis, ossification, or disruption of the blood-perilymph barrier. CCR2 knockout (KO) mice suffered the most severe hearing loss. CX3CR1 KO mice demonstrated an intermediate phenotype with greater susceptibility to hearing loss compared to control mice. Elimination of CX3CR1 mononuclear phagocytes during the first 2 weeks after meningitis in CX3CR1-DTR transgenic mice did not protect mice from any of the systemic or hearing sequelae of pneumococcal meningitis. CONCLUSIONS Pneumococcal meningitis can have devastating effects on cochlear structure and function, although not all mice experienced hearing loss or cochlear damage. Meningitis can result in rapid progression of hearing loss with fibrosis starting at four DPI and ossification within 2 weeks of infection detectable by light microscopy. The inflammatory response to bacterial meningitis is robust and can affect all three scalae. Our results suggest that CCR2 may assist in controlling infection and maintaining cochlear patency, as CCR2 knockout mice experienced more severe disease, more rapid hearing loss, and more advanced cochlear ossification after pneumococcal meningitis. CX3CR1 also may play an important role in the maintenance of cochlear patency.
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Affiliation(s)
- Keiko Hirose
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA.
| | - Song Zhe Li
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA
| | - Ruth Gill
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA
- Department of Obstetric and Gynecology, Washington University, St. Louis, MO, USA
| | - Jared Hartsock
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA
- Turner Scientific, Jacksonville, IL, USA
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Li Y, Wang L, Gao Z, Zhou J, Xie S, Li G, Hou C, Wang Z, Lv Z, Wang R, Han G. Neuropeptide Calcitonin Gene-Related Peptide Promotes Immune Homeostasis of Bacterial Meningitis by Inducing Major Histocompatibility Complex Class II Ubiquitination. J Infect Dis 2024; 229:855-865. [PMID: 37603461 DOI: 10.1093/infdis/jiad358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/20/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND Calcitonin gene-related peptide (CGRP), an immunomodulatory neuropeptide, is important for regulating pain transmission, vasodilation, and the inflammatory response. However, the molecular mechanisms of the CGRP-mediated immune response remain unknown. METHODS The effects of CGRP on bacterial meningitis (BM) and its underlying mechanisms were investigated in BM mice in vivo and macrophages in vitro. RESULTS Peripheral injection of CGRP attenuated cytokine storms and protected mice from fatal pneumococcal meningitis, marked by increased bacterial clearance, improved neuroethology, and reduced mortality. When the underlying mechanisms were investigated, we found that CGRP induces proteasome-dependent degradation of major histocompatibility complex class II (MHC-II) in macrophages and then inhibits CD4+ T-cell activation. MARCH1 was identified as an E3 ligase that can be induced by CGRP engagement and promote K48-linked ubiquitination and degradation of MHC-II in macrophages. These results provide new insights into neuropeptide CGRP-mediated immune regulation mechanisms. CONCLUSIONS We conclude that targeting the nervous system and manipulating neuroimmune communication is a promising strategy for treating intracranial infections like BM.
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Affiliation(s)
- Yuxiang Li
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
| | - Lanying Wang
- Joint National Laboratory for Antibody Drug Engineering, School of Medicine, Henan University, Kaifeng
| | - Zhenfang Gao
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
| | - Jie Zhou
- Joint National Laboratory for Antibody Drug Engineering, School of Medicine, Henan University, Kaifeng
| | - Shun Xie
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
| | - Ge Li
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
| | - Chunmei Hou
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
| | - Zhiding Wang
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
| | - Zhonglin Lv
- Department of Hematology, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese People's Liberation Army General Hospital, Beijing
| | - Renxi Wang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Gencheng Han
- Department of Neuroimmune and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing
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van de Beek D, Brouwer MC, Koedel U, Wall EC. Community-acquired bacterial meningitis. Lancet 2021; 398:1171-1183. [PMID: 34303412 DOI: 10.1016/s0140-6736(21)00883-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/25/2021] [Accepted: 04/07/2021] [Indexed: 12/19/2022]
Abstract
Progress has been made in the prevention and treatment of community-acquired bacterial meningitis during the past three decades but the burden of the disease remains high globally. Conjugate vaccines against the three most common causative pathogens (Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae) have reduced the incidence of disease, but with the replacement by non-vaccine pneumococcal serotypes and the emergence of bacterial strains with reduced susceptibility to antimicrobial treatment, meningitis continues to pose a major health challenge worldwide. In patients presenting with bacterial meningitis, typical clinical characteristics (such as the classic triad of neck stiffness, fever, and an altered mental status) might be absent and cerebrospinal fluid examination for biochemistry, microscopy, culture, and PCR to identify bacterial DNA are essential for the diagnosis. Multiplex PCR point-of-care panels in cerebrospinal fluid show promise in accelerating the diagnosis, but diagnostic accuracy studies to justify routine implementation are scarce and randomised, controlled studies are absent. Early administration of antimicrobial treatment (within 1 hour of presentation) improves outcomes and needs to be adjusted according to local emergence of drug resistance. Adjunctive dexamethasone treatment has proven efficacy beyond the neonatal age but only in patients from high-income countries. Further progress can be expected from implementing preventive measures, especially the development of new vaccines, implementation of hospital protocols aimed at early treatment, and new treatments targeting checkpoints of the inflammatory cascade.
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Affiliation(s)
- Diederik van de Beek
- Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef, Amsterdam, Netherlands.
| | - Matthijs C Brouwer
- Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef, Amsterdam, Netherlands
| | - Uwe Koedel
- Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Emma C Wall
- Research Department of Infection, University College London, London, UK; Francis Crick Institute, London, UK
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Too LK, Hunt N, Simunovic MP. The Role of Inflammation and Infection in Age-Related Neurodegenerative Diseases: Lessons From Bacterial Meningitis Applied to Alzheimer Disease and Age-Related Macular Degeneration. Front Cell Neurosci 2021; 15:635486. [PMID: 33867940 PMCID: PMC8044768 DOI: 10.3389/fncel.2021.635486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/05/2021] [Indexed: 12/21/2022] Open
Abstract
Age-related neurodegenerative diseases, such as Alzheimer disease (AD) and age-related macular degeneration (AMD), are multifactorial and have diverse genetic and environmental risk factors. Despite the complex nature of the diseases, there is long-standing, and growing, evidence linking microbial infection to the development of AD dementia, which we summarize in this article. Also, we highlight emerging research findings that support a role for parainfection in the pathophysiology of AMD, a disease of the neurosensory retina that has been shown to share risk factors and pathological features with AD. Acute neurological infections, such as Bacterial Meningitis (BM), trigger inflammatory events that permanently change how the brain functions, leading to lasting cognitive impairment. Neuroinflammation likewise is a known pathological event that occurs in the early stages of chronic age-related neurodegenerative diseases AD and AMD and might be triggered as a parainfectious event. To date, at least 16 microbial pathogens have been linked to the development of AD; on the other hand, investigation of a microbe-AMD relationship is in its infancy. This mini-review article provides a synthesis of existing evidence indicating a contribution of parainfection in the aetiology of AD and of emerging findings that support a similar process in AMD. Subsequently, it describes the major immunopathological mechanisms that are common to BM and AD/AMD. Together, this evidence leads to our proposal that both AD and AMD may have an infectious aetiology that operates through a dysregulated inflammatory response, leading to deleterious outcomes. Last, it draws fresh insights from the existing literature about potential therapeutic options for BM that might alleviate neurological disruption associated with infections, and which could, by extension, be explored in the context of AD and AMD.
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Affiliation(s)
- Lay Khoon Too
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pathology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Nicholas Hunt
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia
| | - Matthew P. Simunovic
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia
- Sydney Eye Hospital, Sydney, NSW, Australia
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Cools F, Delputte P, Cos P. The search for novel treatment strategies for Streptococcus pneumoniae infections. FEMS Microbiol Rev 2021; 45:6064299. [PMID: 33399826 PMCID: PMC8371276 DOI: 10.1093/femsre/fuaa072] [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: 06/30/2020] [Accepted: 01/01/2021] [Indexed: 12/13/2022] Open
Abstract
This review provides an overview of the most important novel treatment strategies against Streptococcus pneumoniae infections published over the past 10 years. The pneumococcus causes the majority of community-acquired bacterial pneumonia cases, and it is one of the prime pathogens in bacterial meningitis. Over the last 10 years, extensive research has been conducted to prevent severe pneumococcal infections, with a major focus on (i) boosting the host immune system and (ii) discovering novel antibacterials. Boosting the immune system can be done in two ways, either by actively modulating host immunity, mostly through administration of selective antibodies, or by interfering with pneumococcal virulence factors, thereby supporting the host immune system to effectively overcome an infection. While several of such experimental therapies are promising, few have evolved to clinical trials. The discovery of novel antibacterials is hampered by the high research and development costs versus the relatively low revenues for the pharmaceutical industry. Nevertheless, novel enzymatic assays and target-based drug design, allow the identification of targets and the development of novel molecules to effectively treat this life-threatening pathogen.
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Affiliation(s)
- F Cools
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - P Delputte
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - P Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
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Too LK, Mitchell A. Brains, bacteria and behaviors: the role of interferon-gamma in the pathogenesis of pneumococcal meningitis. Neural Regen Res 2021; 16:125-126. [PMID: 32788465 PMCID: PMC7818887 DOI: 10.4103/1673-5374.286968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Lay Khoon Too
- Molecular Immunopathology Unit, Bosch Institute and School of Medical Sciences; Save Sight Institute, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Andrew Mitchell
- Materials Characterisation and Fabrication Platform, Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, Australia
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Pan SD, Grandgirard D, Leib SL. Adjuvant Cannabinoid Receptor Type 2 Agonist Modulates the Polarization of Microglia Towards a Non-Inflammatory Phenotype in Experimental Pneumococcal Meningitis. Front Cell Infect Microbiol 2020; 10:588195. [PMID: 33251159 PMCID: PMC7674855 DOI: 10.3389/fcimb.2020.588195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/14/2020] [Indexed: 12/26/2022] Open
Abstract
Background Microglia initiates and sustains the inflammatory reaction that drives the pathogenesis of pneumococcal meningitis. The expression of the G-protein cannabinoid receptor type 2 (CB2) in the brain is low, but is upregulated in glial cells during infection. Its activation down-regulates pro-inflammatory processes, driving microglia towards an anti-inflammatory phenotype. CB2 agonists are therefore therapeutic candidates in inflammatory conditions like pneumococcal meningitis. We evaluated the effects of JWH-133, a specific CB2 agonist on microglial cells, inflammation, and damage driven by S. pneumoniae in vitro and in experimental pneumococcal meningitis. Materials/methods Primary mixed glial cultures were stimulated with live or heat-inactivated S. pneumoniae, or lipopolysaccharide and treated with JWH-133 or vehicle. Nitric oxide and cytokines levels were measured in the supernatant. In vivo, pneumococcal meningitis was induced by intracisternal injection of live S. pneumoniae in 11 days old Wistar rats. Animals were treated with antibiotics (Ceftriaxone, 100 mg/kg, s.c. bid) and JWH-133 (1 mg/kg, i.p. daily) or vehicle (10% Ethanol in saline, 100 µl/25g body weight) at 18 h after infection. Brains were harvested at 24 and 42 h post infection (hpi) for histological assessment of hippocampal apoptosis and cortical damage and determination of cyto/chemokines in tissue homogenates. Microglia were characterized using Iba-1 immunostaining. Inflammation in brain homogenates was determined using membrane-based antibody arrays. Results In vitro, nitric oxide and cytokines levels were significantly lowered by JWH-133 treatment. In vivo, clinical parameters were not affected by the treatment. JWH-133 significantly lowered microglia activation assessed by quantification of cell process length and endpoints per microglia. Animals treated with JWH-133 demonstrated significantly lower parenchymal levels of chemokines (CINC-1, CINC-2α/β, and MIP-3α), TIMP-1, and IL-6 at 24 hpi, and CINC-1, MIP-1α, and IL-1α at 42 hpi. Quantitative analysis of brain damage did not reveal an effect of JWH-133. Conclusions JWH-133 attenuates microglial activation and downregulates the concentrations of pro-inflammatory mediators in pneumococcal infection in vitro and in vivo. However, we didn't observe a reduction in cortical or hippocampal injury. This data provides evidence that inhibition of microglia by adjuvant CB2 agonists therapy effectively downmodulates neuroinflammation but does not reduce brain damage in experimental pneumococcal meningitis.
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Affiliation(s)
- Steven D Pan
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Denis Grandgirard
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Stephen L Leib
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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Ricci S, Grandgirard D, Masouris I, Braccini T, Pozzi G, Oggioni MR, Koedel U, Leib SL. Combined therapy with ceftriaxone and doxycycline does not improve the outcome of meningococcal meningitis in mice compared to ceftriaxone monotherapy. BMC Infect Dis 2020; 20:505. [PMID: 32660552 PMCID: PMC7359289 DOI: 10.1186/s12879-020-05226-w] [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: 04/15/2020] [Accepted: 07/03/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Meningococcal meningitis (MM) is a life-threatening disease associated with approximately 10% case fatality rates and neurological sequelae in 10-20% of the cases. Recently, we have shown that the matrix metalloproteinase (MMP) inhibitor BB-94 reduced brain injury in a mouse model of MM. The present study aimed to assess whether doxycycline (DOX), a tetracycline that showed a neuroprotective effect as adjuvant therapy in experimental pneumococcal meningitis (PM), would also exert a beneficial effect when given as adjunctive therapy to ceftriaxone (CRO) in experimental MM. METHODS BALB/c mice were infected by the intracisternal route with a group C Neisseria meningitidis strain. Eighteen h post infection (hpi), animals were randomised for treatment with CRO [100 mg/kg subcutaneously (s.c.)], CRO plus DOX (30 mg/kg s.c.) or saline (control s.c.). Antibiotic treatment was repeated 24 and 40 hpi. Mouse survival and clinical signs, bacterial counts in cerebella, brain damage, MMP-9 and cyto/chemokine levels were assessed 48 hpi. RESULTS Analysis of bacterial load in cerebella indicated that CRO and CRO + DOX were equally effective at controlling meningococcal replication. No differences in survival were observed between mice treated with CRO (94.4%) or CRO + DOX (95.5%), (p > 0.05). Treatment with CRO + DOX significantly diminished both the number of cerebral hemorrhages (p = 0.029) and the amount of MMP-9 in the brain (p = 0.046) compared to untreated controls, but not to CRO-treated animals (p > 0.05). Levels of inflammatory markers in the brain of mice that received CRO or CRO + DOX were not significantly different (p > 0.05). Overall, there were no significant differences in the parameters assessed between the groups treated with CRO alone or CRO + DOX. CONCLUSIONS Treatment with CRO + DOX showed similar bactericidal activity to CRO in vivo, suggesting no antagonist effect of DOX on CRO. Combined therapy significantly improved mouse survival and disease severity compared to untreated animals, but addition of DOX to CRO did not offer significant benefits over CRO monotherapy. In contrast to experimental PM, DOX has no adjunctive activity in experimental MM.
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Affiliation(s)
- Susanna Ricci
- Department of Medical Biotechnologies, Laboratory of Molecular Microbiology and Biotechnology (LA.M.M.B.), Ospedale Santa Maria alle Scotte, University of Siena, Siena, Italy. .,ESCMID Study Group for Infectious Diseases of the Brain (ESGIB), Basel, Switzerland.
| | - Denis Grandgirard
- ESCMID Study Group for Infectious Diseases of the Brain (ESGIB), Basel, Switzerland.,Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Ilias Masouris
- Department of Neurology, Ludwig-Maximilians University, Munich, Germany
| | - Tiziana Braccini
- Department of Medical Biotechnologies, Laboratory of Molecular Microbiology and Biotechnology (LA.M.M.B.), Ospedale Santa Maria alle Scotte, University of Siena, Siena, Italy
| | - Gianni Pozzi
- Department of Medical Biotechnologies, Laboratory of Molecular Microbiology and Biotechnology (LA.M.M.B.), Ospedale Santa Maria alle Scotte, University of Siena, Siena, Italy
| | - Marco R Oggioni
- ESCMID Study Group for Infectious Diseases of the Brain (ESGIB), Basel, Switzerland.,Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Uwe Koedel
- ESCMID Study Group for Infectious Diseases of the Brain (ESGIB), Basel, Switzerland.,Department of Neurology, Ludwig-Maximilians University, Munich, Germany
| | - Stephen L Leib
- ESCMID Study Group for Infectious Diseases of the Brain (ESGIB), Basel, Switzerland.,Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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Diagnostic Yield of Pneumococcal Antigen Detection in Cerebrospinal Fluid for Diagnosis of Pneumococcal Meningitis Among Children in China. Indian Pediatr 2020. [DOI: 10.1007/s13312-020-1701-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Muri L, Grandgirard D, Buri M, Perny M, Leib SL. Combined effect of non-bacteriolytic antibiotic and inhibition of matrix metalloproteinases prevents brain injury and preserves learning, memory and hearing function in experimental paediatric pneumococcal meningitis. J Neuroinflammation 2018; 15:233. [PMID: 30131074 PMCID: PMC6103863 DOI: 10.1186/s12974-018-1272-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/08/2018] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Pneumococcal meningitis is associated with high mortality and morbidity rates. Up to 50% of survivors show neurologic sequelae including hearing loss, cognitive impairments and learning disabilities, being particularly detrimental in affected infants and children where adjuvant therapy with dexamethasone has no proven beneficial effect. We evaluated the effect of concomitantly targeting specific pathophysiological mechanisms responsible for brain damage-i.e. matrix-metalloproteinase (MMP) activity and the exacerbated cerebral inflammation provoked through antibiotic-induced bacterial lysis. Here, we combined adjunctive therapies previously shown to be neuroprotective when used as single adjuvant therapies. METHODS Eleven-day-old Wistar rats were infected intracisternally with 6.44 ± 2.17 × 103 CFU Streptococcus pneumoniae and randomised for treatment with ceftriaxone combined with (a) single adjuvant therapy with daptomycin (n = 24), (b) single adjuvant therapy with Trocade (n = 24), (c) combined adjuvant therapy (n = 66) consisting of daptomycin and Trocade, or (d) ceftriaxone monotherapy (n = 42). Clinical parameters and inflammatory CSF cytokine levels were determined during acute meningitis. Cortical damage and hippocampal apoptosis were assessed 42 h after infection. Morris water maze and auditory brainstem responses were used to assess neurofunctional outcome 3 weeks after infection. RESULTS We found significantly reduced apoptosis in the hippocampal subgranular zone in infant rats receiving adjuvant Trocade (p < 0.01) or combined adjuvant therapy (p < 0.001). Cortical necrosis was significantly reduced in rats treated with adjuvant daptomycin (p < 0.05) or combined adjuvant therapy (p < 0.05) compared to ceftriaxone monotherapy. Six hours after treatment initiation, CSF cytokine levels were significantly reduced for TNF-α (p < 0.01), IL-1β (p < 0.01), IL-6 (p < 0.001) and IL-10 (p < 0.01) in animals receiving combined adjuvant intervention compared to ceftriaxone monotherapy. Importantly, combined adjuvant therapy significantly improved learning and memory performance in infected animals and reduced hearing loss (77.14 dB vs 60.92 dB, p < 0.05) by preserving low frequency hearing capacity, compared to ceftriaxone monotherapy. CONCLUSION Combined adjuvant therapy with the non-bacteriolytic antibiotic daptomycin and the MMP inhibitor Trocade integrates the neuroprotective effects of both single adjuvants in experimental paediatric pneumococcal meningitis by reducing neuroinflammation and brain damage, thereby improving neurofunctional outcome. This strategy represents a promising therapeutic option to improve the outcome of paediatric patients suffering from pneumococcal meningitis.
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Affiliation(s)
- Lukas Muri
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3001 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, Freiestrasse 1, 3012 Bern, Switzerland
| | - Denis Grandgirard
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3001 Bern, Switzerland
| | - Michelle Buri
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3001 Bern, Switzerland
| | - Michael Perny
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3001 Bern, Switzerland
| | - Stephen L. Leib
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3001 Bern, Switzerland
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