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Yekani M, Memar MY. Immunologic biomarkers for bacterial meningitis. Clin Chim Acta 2023; 548:117470. [PMID: 37419301 DOI: 10.1016/j.cca.2023.117470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/09/2023]
Abstract
Meningitis is defined as the inflammation of the meninges that is most often caused by various bacterial and viral pathogens, and is associated with high rates of mortality and morbidity. Early detection of bacterial meningitis is essential to appropriate antibiotic therapy. Alterations in immunologic biomarkers levels have been considered the diagnostic approach in medical laboratories for the identifying of infections. The early increasing immunologic mediators such as cytokines and acute phase proteins (APPs) during bacterial meningitis have made they significant indicators for laboratory diagnosis. Immunology biomarkers showed wide variable sensitivity and specificity values that influenced by different reference values, selected a certain cutoff point, methods of detection, patient characterization and inclusion criteria, as well as etiology of meningitis and time of CSF or blood specimens' collection. This study provides an overview of different immunologic biomarkers as diagnostic markers for the identification of bacterial meningitis and their efficiencies in the differentiating of bacterial from viral meningitis.
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Affiliation(s)
- Mina Yekani
- Department of Microbiology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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2
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Paez-Gonzalez P, Lopez-de-San-Sebastian J, Ceron-Funez R, Jimenez AJ, Rodríguez-Perez LM. Therapeutic strategies to recover ependymal barrier after inflammatory damage: relevance for recovering neurogenesis during development. Front Neurosci 2023; 17:1204197. [PMID: 37397456 PMCID: PMC10308384 DOI: 10.3389/fnins.2023.1204197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/22/2023] [Indexed: 07/04/2023] Open
Abstract
The epithelium covering the surfaces of the cerebral ventricular system is known as the ependyma, and is essential for maintaining the physical and functional integrity of the central nervous system. Additionally, the ependyma plays an essential role in neurogenesis, neuroinflammatory modulation and neurodegenerative diseases. Ependyma barrier is severely affected by perinatal hemorrhages and infections that cross the blood brain barrier. The recovery and regeneration of ependyma after damage are key to stabilizing neuroinflammatory and neurodegenerative processes that are critical during early postnatal ages. Unfortunately, there are no effective therapies to regenerate this tissue in human patients. Here, the roles of the ependymal barrier in the context of neurogenesis and homeostasis are reviewed, and future research lines for development of actual therapeutic strategies are discussed.
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Affiliation(s)
- Patricia Paez-Gonzalez
- Department of Cell Biology, Genetics and Physiology, University of Malaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina-IBIMA Plataforma BIONAND, Málaga, Spain
| | | | - Raquel Ceron-Funez
- Department of Cell Biology, Genetics and Physiology, University of Malaga, Málaga, Spain
| | - Antonio J. Jimenez
- Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina-IBIMA Plataforma BIONAND, Málaga, Spain
| | - Luis Manuel Rodríguez-Perez
- Department of Cell Biology, Genetics and Physiology, University of Malaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina-IBIMA Plataforma BIONAND, Málaga, Spain
- Department of Human Physiology, Human Histology, Pathological Anatomy and Sports, University of Malaga, Málaga, Spain
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3
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Bagatella S, Haghayegh Jahromi N, Monney C, Polidori M, Gall FM, Marchionatti E, Serra F, Riedl R, Engelhardt B, Oevermann A. Bovine neutrophil chemotaxis to Listeria monocytogenes in neurolisteriosis depends on microglia-released rather than bacterial factors. J Neuroinflammation 2022; 19:304. [PMID: 36527076 PMCID: PMC9758797 DOI: 10.1186/s12974-022-02653-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 11/21/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Listeria monocytogenes (Lm) is a bacterial pathogen of major concern for humans and ruminants due to its neuroinvasive potential and its ability to cause deadly encephalitis (neurolisteriosis). On one hand, polymorphonuclear neutrophils (PMN) are key players in the defense against Lm, but on the other hand intracerebral infiltration with PMN is associated with significant neural tissue damage. Lm-PMN interactions in neurolisteriosis are poorly investigated, and factors inducing PMN chemotaxis to infectious foci containing Lm in the central nervous system (CNS) remain unidentified. METHODS In this study, we assessed bovine PMN chemotaxis towards Lm and supernatants of infected endogenous brain cell populations in ex vivo chemotaxis assays, to identify chemotactic stimuli for PMN chemotaxis towards Lm in the brain. In addition, microglial secretion of IL-8 was assessed both ex vivo and in situ. RESULTS Our data show that neither Lm cell wall components nor intact bacteria elicit chemotaxis of bovine PMN ex vivo. Moreover, astrocytes and neural cells fail to induce bovine PMN chemotaxis upon infection. In contrast, supernatant from Lm infected microglia readily induced chemotaxis of bovine PMN. Microglial expression and secretion of IL-8 was identified during early Lm infection in vitro and in situ, although IL-8 blocking with a specific antibody could not abrogate PMN chemotaxis towards Lm infected microglial supernatant. CONCLUSIONS These data provide evidence that host-derived rather than bacterial factors trigger PMN chemotaxis to bacterial foci in the CNS, that microglia have a primary role as initiators of bovine PMN chemotaxis into the brain during neurolisteriosis and that blockade of these factors could be a therapeutic target to limit intrathecal PMN chemotaxis and PMN associated damage in neurolisteriosis.
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Affiliation(s)
- Stefano Bagatella
- grid.5734.50000 0001 0726 5157Division of Neurological Sciences, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, CH-3012 Bern, Switzerland ,grid.5734.50000 0001 0726 5157Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Neda Haghayegh Jahromi
- grid.5734.50000 0001 0726 5157Theodor Kocher Institute (TKI), University of Bern, Bern, Switzerland
| | - Camille Monney
- grid.5734.50000 0001 0726 5157Division of Neurological Sciences, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, CH-3012 Bern, Switzerland
| | - Margherita Polidori
- grid.5734.50000 0001 0726 5157Division of Neurological Sciences, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, CH-3012 Bern, Switzerland ,grid.5734.50000 0001 0726 5157Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Flavio Max Gall
- grid.19739.350000000122291644Institute of Chemistry and Biotechnology, Competence Center for Drug Discovery, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
| | - Emma Marchionatti
- grid.5734.50000 0001 0726 5157Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Rainer Riedl
- grid.19739.350000000122291644Institute of Chemistry and Biotechnology, Competence Center for Drug Discovery, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
| | - Britta Engelhardt
- grid.5734.50000 0001 0726 5157Theodor Kocher Institute (TKI), University of Bern, Bern, Switzerland
| | - Anna Oevermann
- grid.5734.50000 0001 0726 5157Division of Neurological Sciences, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, CH-3012 Bern, Switzerland
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4
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Elevated Free Phosphatidylcholine Levels in Cerebrospinal Fluid Distinguish Bacterial from Viral CNS Infections. Cells 2021; 10:cells10051115. [PMID: 34066349 PMCID: PMC8148106 DOI: 10.3390/cells10051115] [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: 03/18/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 12/19/2022] Open
Abstract
The identification of CSF biomarkers for bacterial meningitis can potentially improve diagnosis and understanding of pathogenesis, and the differentiation from viral CNS infections is of particular clinical importance. Considering that substantial changes in CSF metabolites in CNS infections have recently been demonstrated, we compared concentrations of 188 metabolites in CSF samples from patients with bacterial meningitis (n = 32), viral meningitis/encephalitis (n = 34), and noninflamed controls (n = 66). Metabolite reprogramming in bacterial meningitis was greatest among phosphatidylcholines, and concentrations of all 54 phosphatidylcholines were significantly (p = 1.2 × 10−25–1.5 × 10−4) higher than in controls. Indeed, all biomarkers for bacterial meningitis vs. viral meningitis/encephalitis with an AUC ≥ 0.86 (ROC curve analysis) were phosphatidylcholines. Four of the five most accurate (AUC ≥ 0.9) phosphatidylcholine biomarkers had higher sensitivity and negative predictive values than CSF lactate or cell count. Concentrations of the 10 most accurate phosphatidylcholine biomarkers were lower in meningitis due to opportunistic pathogens than in meningitis due to typical meningitis pathogens, and they correlated most strongly with parameters reflecting blood–CSF barrier dysfunction and CSF lactate (r = 0.73–0.82), less so with CSF cell count, and not with blood CRP. In contrast to the elevated phosphatidylcholine concentrations in CSF, serum concentrations remained relatively unchanged. Taken together, these results suggest that increased free CSF phosphatidylcholines are sensitive biomarkers for bacterial meningitis and do not merely reflect inflammation but are associated with local disease and a shift in CNS metabolism.
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5
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Pota V, Passavanti MB, Coppolino F, Di Zazzo F, De Nardis L, Esposito R, Fiore M, Mangoni di Santostefano GSRC, Aurilio C, Sansone P, Pace MC. Septic shock due to Escherichia coli meningoencephalitis treated with immunoglobulin-M-enriched immunoglobulin preparation as adjuvant therapy: a case report. J Med Case Rep 2021; 15:138. [PMID: 33775244 PMCID: PMC8005330 DOI: 10.1186/s13256-021-02731-7] [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: 08/07/2019] [Accepted: 02/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gram-negative bacteria are an uncommon etiology of spontaneous community-acquired adult meningitis and meningoencephalitis. Escherichia coli is a Gram-negative bacterium that is normally present in the intestinal microbial pool. Some Escherichia coli strains can cause diseases in humans and animals, with both intestinal and extraintestinal manifestations (extraintestinal pathogenic Escherichia coli) such as urinary tract infections, bacteremia with sepsis, and, more rarely, meningitis. Meningitis continues to be an important cause of mortality throughout the world, despite progress in antimicrobial chemotherapy and supportive therapy. The mortality rate fluctuates between 15% and 40%, and about 50% of the survivors report neurological sequelae. The majority of Escherichia coli meningitis cases develop as a result of hematogenous spread, with higher degrees of bacteremia also being related to worse prognosis. Cases presenting with impaired consciousness (that is, coma) are also reported to have poorer outcomes. CASE PRESENTATION We describe the case of a 48-year-old caucasian woman with meningoencephalitis, with a marked alteration of consciousness on admission, and septic shock secondary to pyelonephritis caused by Escherichia coli, treated with targeted antimicrobial therapy and immunoglobulin-M-enriched immunoglobulin (Pentaglobin) preparation as adjuvant therapy. CONCLUSION Despite the dramatic presentation of the patient on admission, the conflicting data on the use of immunoglobulins in septic shock, and the lack of evidence regarding their use in adult Escherichia coli meningoencephalitis, we obtained a remarkable improvement of her clinical condition, accompanied by partial resolution of her neurological deficits.
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Affiliation(s)
- V Pota
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy.
| | - M B Passavanti
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - F Coppolino
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - F Di Zazzo
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - L De Nardis
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - R Esposito
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - M Fiore
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | | | - C Aurilio
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - P Sansone
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - M C Pace
- Dept of Women, Child, General and Specialist Surgery, University of Campania "L. Vanvitelli", Naples, Italy
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6
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Woo YH, Martinez LR. Cryptococcus neoformans-astrocyte interactions: effect on fungal blood brain barrier disruption, brain invasion, and meningitis progression. Crit Rev Microbiol 2021; 47:206-223. [PMID: 33476528 DOI: 10.1080/1040841x.2020.1869178] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cryptococcus neoformans is an opportunistic, neurotropic, and encapsulated fungus that causes life-threatening cryptococcal meningitis (CM), especially in regions of the world where AIDS is endemic. The polysaccharide capsule of C. neoformans is the fungus major virulent factor, being copiously released during infection and causing immunosuppressive defects in the host. Although the capsular material is commonly associated with reactive astrocytes in fatal CM, little is known about the molecular and cellular interactions among astroglia and C. neoformans. As astrocytes also make up the neurovascular unit at the blood-brain barrier (BBB), which C. neoformans must transverse to colonize the central nervous system and cause CM; these cells may play a significant regulatory role in the prevention and progression of infection. For example, astrocytes are implicated in neurological disease including the regulation of cerebral intracranial pressure, immune function, and water homeostasis. Hence, in this review, we provide a general overview of astroglia biology and discuss the current knowledge on C. neoformans-astrocyte interactions including their involvement in the development of CM. This "gliocentric view" of cerebral cryptococcosis suggests that therapeutic interventions particularly targeting at preserving the neuroprotective function of astrocytes may be used in preventing and managing C. neoformans BBB transmigration, brain invasion, colonization, and meningitis.
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Affiliation(s)
- Yeon Hwa Woo
- Department of Metallurgical, Materials and Biomedical Engineering, College of Engineering, The University of Texas at El Paso, El Paso, TX, USA
| | - Luis R Martinez
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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7
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Interactions and Signal Transduction Pathways Involved during Central Nervous System Entry by Neisseria meningitidis across the Blood-Brain Barriers. Int J Mol Sci 2020; 21:ijms21228788. [PMID: 33233688 PMCID: PMC7699760 DOI: 10.3390/ijms21228788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/18/2020] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative diplococcus Neisseria meningitidis, also called meningococcus, exclusively infects humans and can cause meningitis, a severe disease that can lead to the death of the afflicted individuals. To cause meningitis, the bacteria have to enter the central nervous system (CNS) by crossing one of the barriers protecting the CNS from entry by pathogens. These barriers are represented by the blood–brain barrier separating the blood from the brain parenchyma and the blood–cerebrospinal fluid (CSF) barriers at the choroid plexus and the meninges. During the course of meningococcal disease resulting in meningitis, the bacteria undergo several interactions with host cells, including the pharyngeal epithelium and the cells constituting the barriers between the blood and the CSF. These interactions are required to initiate signal transduction pathways that are involved during the crossing of the meningococci into the blood stream and CNS entry, as well as in the host cell response to infection. In this review we summarize the interactions and pathways involved in these processes, whose understanding could help to better understand the pathogenesis of meningococcal meningitis.
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8
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Auger JP, Benoit-Biancamano MO, Bédard C, Segura M, Gottschalk M. Differential role of MyD88 signaling in Streptococcus suis serotype 2-induced systemic and central nervous system diseases. Int Immunol 2020; 31:697-714. [PMID: 30944920 DOI: 10.1093/intimm/dxz033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/29/2019] [Indexed: 02/06/2023] Open
Abstract
Streptococcus suis serotype 2 is an important porcine bacterial pathogen and a zoonotic agent responsible for sudden death, septic shock and meningitis, with exacerbated inflammation being a hallmark of the systemic and central nervous system (CNS) infections. However, S. suis serotype 2 strains are genetically and phenotypically heterogeneous, being composed of a multitude of sequence types (STs) whose virulence greatly varies. Yet, most studies have used 'classical' virulent Eurasian ST1 or ST7 strains, even though ST25 and ST28 strains account for most isolates in North America. While recognition of S. suis by innate immune cells has been associated with the myeloid differentiation primary response 88 (MyD88)-dependent Toll-like receptor (TLR) pathway in vitro, particularly surface-associated TLR2, little information is available regarding its role in vivo. This study demonstrates for the first time a differential role of MyD88 signaling in S. suis-induced systemic and CNS diseases, regardless of strain background diversity. The MyD88-dependent pathway is critical for the development of systemic disease via its role in inflammation, which subsequently controls bacterial burden. However, and differently from what has been described in vitro, TLR2 and TLR4 individually do not contribute to systemic disease, suggesting possible compensation in their absence and/or a collaborative role with other MyD88-dependent TLRs. On the other hand, CNS disease does not necessarily require MyD88 signaling and, consequently, neither TLR2 nor TLR4, suggesting a partial implication of other pathways. Finally, regardless of its notable heterogeneity, recognition of S. suis serotype 2 appears to be similar, indicating that recognized components are conserved motifs.
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Affiliation(s)
- Jean-Philippe Auger
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Disease Research Center (CRIPA), Saint-Hyacinthe, Quebec, Canada.,Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Marie-Odile Benoit-Biancamano
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Disease Research Center (CRIPA), Saint-Hyacinthe, Quebec, Canada.,Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Christian Bédard
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Disease Research Center (CRIPA), Saint-Hyacinthe, Quebec, Canada.,Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Marcelo Gottschalk
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Disease Research Center (CRIPA), Saint-Hyacinthe, Quebec, Canada.,Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
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9
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Localization of Pasteurella multocida antigens in the brains of pigs naturally infected with Pasteurellosis revealing a newer aspect of pathogenesis. Microb Pathog 2020; 140:103968. [PMID: 31927003 DOI: 10.1016/j.micpath.2020.103968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/30/2019] [Accepted: 01/05/2020] [Indexed: 11/20/2022]
Abstract
Pasteurella multocida is an economically important respiratory pathogen of pigs confronting swine industry worldwide. Despite extensive research over the decades, its pathogenesis is still poorly understood. Recent reports have demonstrated the nervous system affection as a newer aspect of pathogenesis by Pasteurella multocida type B:2 in Haemorrhagic Septicemia, but there are no reports of the involvement of nervous system by P. multocida in pigs. Therefore, the study was aimed to explore the neurovirulence of Pasteurella multocida in naturally infected pigs. A total of 15 brains were collected from the natural cases of pig mortality suggestive of Pasteurellosis. Grossly, the leptomeninges were markedly congested and brains were oedematously swollen. Histologically, there was moderate to severe fibrinohaemorrhagic and mononuclear cells exudates present in the leptomeningeal tissue and cerebrospinal spaces. Similar vascular inflammatory lesions (perivascular and perineuronal) along with gliosis, neuronal degeneration and necrosis were noted in various subanatomical sites of the brain (cerebrum, cerebellum, brainstem and spinal cord). The culture and biochemical tests showed the presence of P. multocida within the brain tissue. P. multocida type specific antibody staining in the brain tissues revealed intense distribution of antigens in the inflammatory exudates of meningeal vessels, neurons, glial cells and endothelial cells of the blood vessels contributing its association with neuropathological lesions. Pasteurella multocida specific PCR amplification of capsular polysaccharide gene yielded 460 bp and multiplex PCR showed the involvement of capsular serogroups A &D. All the isolates showed the presence of 10 genes for virulence factors. The disease confirmation of both serotypes was proven by Koch's postulates using Swiss albino mice. Further, histopathological brain lesions along with the immunohistochemical detection of bacterial antigens were corroborated with natural cases of P. multocida as described above. To the best of our knowledge, we first time report the neuroinvasion of P. multocida in naturally infected pigs.
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10
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Mitoma H, Manto M. Disruption of the Blood-Brain Barrier During Neuroinflammatory and Neuroinfectious Diseases. NEUROIMMUNE DISEASES 2019. [PMCID: PMC7121618 DOI: 10.1007/978-3-030-19515-1_7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As the organ of highest metabolic demand, utilizing over 25% of total body glucose utilization via an enormous vasculature with one capillary every 73 μm, the brain evolves a barrier at the capillary and postcapillary venules to prevent toxicity during serum fluctuations in metabolites and hormones, to limit brain swelling during inflammation, and to prevent pathogen invasion. Understanding of neuroprotective barriers has since evolved to incorporate the neurovascular unit (NVU), the blood-cerebrospinal fluid (CSF) barrier, and the presence of CNS lymphatics that allow leukocyte egress. Identification of the cellular and molecular participants in BBB function at the NVU has allowed detailed analyses of mechanisms that contribute to BBB dysfunction in various disease states, which include both autoimmune and infectious etiologies. This chapter will introduce some of the cellular and molecular components that promote barrier function but may be manipulated by inflammatory mediators or pathogens during neuroinflammation or neuroinfectious diseases.
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Affiliation(s)
- Hiroshi Mitoma
- Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan
| | - Mario Manto
- Department of Neurology, CHU-Charleroi, Charleroi, Belgium, Department of Neurosciences, University of Mons, Mons, Belgium
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11
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Xu G, Liu X, Wang Y. The cerebral protective effect and mechanism of action of vitamin B6 adjuvant ceftriaxone in experimental pneumococcal meningitis. Brain Res 2018; 1695:53-64. [PMID: 29800553 DOI: 10.1016/j.brainres.2018.05.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/18/2018] [Accepted: 05/20/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND Pneumococcal meningitis is one of the most common infectious diseases with a high-mortality rate and long-term neurological sequelae, affecting up to 50% of survivors. Pneumococcal compounds are pro-inflammatory mediators that induce an innate immune response and tryptophan degradation through the kynurenine pathway. Vitamin B6 (vitB6) is an important vitamin which acts as a cofactor at the active sites of enzymes that catalyze a great number of reactions involved in the metabolism of tryptophan through the kynurenine pathway and may thus limit the accumulation of neurotoxic metabolites and preserve the cellular energy status. The aim of this study was to investigate the neuroprotective effect of adjuvant treatment with vitB6 in pneumococcal meningitis. METHODS The effects of vitB6 on the clinical symptoms, the expression of kynureninase (KYN), Kynurenic acid (KYNA), nicotinamide adenine dinucleotide (NAD) and cytokines in brain tissue and memory of infant Wistar rats subjected to pneumococcal meningitis were researched. At the same time, Kynurenine 3-monooxygenase (KMO) inhibitor Ro 61-8048 was applied in order to further investigate the brain protective effect of vitB6 in bacterial meningitis. RESULTS Adjuvant therapy of bacterial meningitis with vitB6 could improve the clinical symptoms, learning performance, lead to the maintenance of cellular NAD+ and ATP homeostasis and significantly down-regulate the levels of cytokines in the brain tissue by affecting the KYN pathway. CONCLUSIONS Adjuvant treatment with vitB6 in pneumococcal meningitis could exert neuroprotective effect via increasing the preservation of cellular energy through affecting the KYN pathway and reducing of the inflammatory response.
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Affiliation(s)
- Guixia Xu
- The Pediatric Department of Qilu Hospital, Shandong University, PR China; The Pediatric Department of the Second People's Hospital of Liaocheng, PR China
| | - Xinjie Liu
- The Pediatric Department of Qilu Hospital, Shandong University, PR China.
| | - Ying Wang
- The Pediatric Department of the People's Hospital in Zoucheng, PR China
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12
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Klein RS, Hunter CA. Protective and Pathological Immunity during Central Nervous System Infections. Immunity 2017; 46:891-909. [PMID: 28636958 PMCID: PMC5662000 DOI: 10.1016/j.immuni.2017.06.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/05/2017] [Accepted: 06/05/2017] [Indexed: 02/08/2023]
Abstract
The concept of immune privilege of the central nervous system (CNS) has dominated the study of inflammatory processes in the brain. However, clinically relevant models have highlighted that innate pathways limit pathogen invasion of the CNS and adaptive immunity mediates control of many neural infections. As protective responses can result in bystander damage, there are regulatory mechanisms that balance protective and pathological inflammation, but these mechanisms might also allow microbial persistence. The focus of this review is to consider the host-pathogen interactions that influence neurotropic infections and to highlight advances in our understanding of innate and adaptive mechanisms of resistance as key determinants of the outcome of CNS infection. Advances in these areas have broadened our comprehension of how the immune system functions in the brain and can readily overcome immune privilege.
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Affiliation(s)
- Robyn S Klein
- Departments of Medicine, Pathology and Immunology, Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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13
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Abstract
Cytokines provide cells with the ability to communicate with one another and orchestrate complex multicellular behaviour. There is an emerging understanding of the role that cytokines play in normal homeostatic tissue function and how dysregulation of these cytokine networks is associated with pathological conditions. The central nervous system (CNS), where few blood-borne immune cells circulate, seems to be particularly vulnerable to dysregulated cytokine networks. In degenerative diseases, such as proteopathies, CNS-resident cells are the predominant producers of pro-inflammatory cytokines. By contrast, in classical neuroinflammatory diseases, such as multiple sclerosis and encephalitides, pro-inflammatory cytokines are mainly produced by tissue-invading leukocytes. Whereas the effect of dysregulated cytokine networks in proteopathies is controversial, cytokines delivered to the CNS by invading immune cells are in general detrimental to the tissue. Here, we summarize recent observations on the impact of dysregulated cytokine networks in neuroinflammation.
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14
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Böhland M, Kress E, Stope MB, Pufe T, Tauber SC, Brandenburg LO. Lack of Toll-like receptor 2 results in higher mortality of bacterial meningitis by impaired host resistance. J Neuroimmunol 2016; 299:90-97. [PMID: 27725130 DOI: 10.1016/j.jneuroim.2016.09.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/01/2016] [Accepted: 09/04/2016] [Indexed: 12/17/2022]
Abstract
Bacterial meningitis is - despite therapeutical progress during the last decades - still characterized by high mortality and severe permanent neurogical sequelae. The brain is protected from penetrating pathogens by both the blood-brain barrier and the innate immune system. Invading pathogens are recognized by so-called pattern recognition receptors including the Toll-like receptors (TLR) which are expressed by glial immune cells in the central nervous system. Among these, TLR2 is responsible for the detection of Gram-positive bacteria such as the meningitis-causing pathogen Streptococcus pneumoniae. Here, we used TLR2-deficient mice to investigate the effects on mortality, bacterial growth and inflammation in a mouse model of pneumococcal meningitis. Our results revealed a significantly increased mortality rate and higher bacterial burden in TLR2-deficient mice with pneumococcal meningitis. Furthermore, infected TLR2-deficient mice suffered from a significantly increased pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) and Chemokine (C-C motif) ligand 2 (CCL2) or CCL3 chemokine expression and decreased expression of anti-inflammatory cytokines and antimicrobial peptides. In contrast, glial cell activation assessed by glial cell marker expression was comparable to wildtype mice. Taken together, the results suggest that TLR2 is essential for an efficient immune response against Streptococcus pneumoniae meningitis since lack of the receptor led to a worse outcome by higher mortality due to increased bacterial burden, weakened innate immune response and reduced expression of antimicrobial peptides.
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Affiliation(s)
- Martin Böhland
- Department of Anatomy and Cell Biology, RWTH Aachen University, Germany
| | - Eugenia Kress
- Department of Anatomy and Cell Biology, RWTH Aachen University, Germany
| | - Matthias B Stope
- Department of Urology, University Medicine Greifswald, Greifswald, Germany
| | - Thomas Pufe
- Department of Anatomy and Cell Biology, RWTH Aachen University, Germany
| | - Simone C Tauber
- Department of Neurology, RWTH University Hospital Aachen, Germany
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Lack of Proinflammatory Cytokine Interleukin-6 or Tumor Necrosis Factor Receptor-1 Results in a Failure of the Innate Immune Response after Bacterial Meningitis. Mediators Inflamm 2016; 2016:7678542. [PMID: 27057100 PMCID: PMC4749820 DOI: 10.1155/2016/7678542] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/04/2016] [Indexed: 12/27/2022] Open
Abstract
The most frequent pathogen that causes bacterial meningitis is the Gram-positive bacterium Streptococcus pneumoniae. By entering the brain, host cells will be activated and proinflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) are released. The goal of the current study was to examine the interaction between IL-6 and TNFR1 as receptor for TNF-α and the innate immune response in vivo in a model of Streptococcus pneumoniae-induced meningitis. For the experiments IL-6(-/-), TNFR1(-/-), and TNFR1-IL-6(-/-) KO mice were used. Our results revealed higher mortality rates and bacterial burden after infection in TNFR1(-/-), IL-6(-/-), and TNFR1-IL-6(-/-) mice and a decreased immune response including lower neutrophil infiltration in the meninges of TNFR1(-/-) and TNFR1-IL-6(-/-) mice in contrast to IL-6(-/-) and wild type mice. Furthermore, the increased mortality of TNFR1(-/-) and TNFR1-IL-6(-/-) mice correlated with decreased glial cell activation compared to IL-6(-/-) or wild type mice after pneumococcal meningitis. Altogether, the results show the importance of TNFR1 and IL-6 in the regulation of the innate immune response. The lack of TNFR1 and IL-6 results in higher mortality by weakened immune defence, whereas the lack of TNFR1 results in more severe impairment of the innate immune response than the lack of IL-6 alone.
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COLOMBO ANACAROLINE, RODRIGUES MARCIOL. Fungal colonization of the brain: anatomopathological aspects of neurological cryptococcosis. ACTA ACUST UNITED AC 2015; 87:1293-309. [DOI: 10.1590/0001-3765201520140704] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Brain infection by the fungus Cryptococcus neoformans results in an estimated 500,000 human deaths per annum. Colonization of the central nervous system (CNS) by C. neoformans causes different clinical syndromes that involve interaction of a number of fungal components with distinct brain cells. In this manuscript, our literature review confirmed the notion that the Cryptococcus field is expanding rapidly, but also suggested that studies on neuropathogenesis still represent a small fraction of basic research activity in the field. We therefore discussed anatomical and physiological aspects of the brain during infection by C. neoformans, in addition to mechanisms by which brain resident cells interact with the fungus. This review suggests that multiple efforts are necessary to improve the knowledge on how C. neoformans affects brain cells, in order to enable the generation of new therapeutic tools in a near future.
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Affiliation(s)
- ANA CAROLINE COLOMBO
- Universidade Federal do Rio de Janeiro, Brazil; Universidade Federal do Rio de Janeiro, Brazil
| | - MARCIO L. RODRIGUES
- Universidade Federal do Rio de Janeiro, Brazil; Fundação Oswaldo Cruz, Brazil
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17
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Larsson A, Carlsson L, Lind AL, Gordh T, Bodolea C, Kamali-Moghaddam M, Thulin M. The body mass index (BMI) is significantly correlated with levels of cytokines and chemokines in cerebrospinal fluid. Cytokine 2015; 76:514-518. [PMID: 26188367 DOI: 10.1016/j.cyto.2015.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 12/18/2022]
Abstract
Cytokines and chemokines regulate many functions in the body including the brain. The interactions between adipose tissue and the central nervous system (CNS) are important for the regulation of energy balance. CNS function is also influenced by age. The aim of the present study was to investigate the effects of body mass index (BMI) and age on cytokine and chemokine levels in cerebrospinal fluid. Cerebrospinal fluid samples (n=89) were collected from patients undergoing routine surgical procedures. The samples were analyzed using the multiplex proximity extension assay (PEA) in which 92 different cytokines are measured simultaneously using minute sample volume. We found no significant correlations between age and cytokine levels for any of the studied markers. In contrast, at a false discovery rate of 10%, 19 markers were significantly associated with BMI (in decreasing significance: FGF-5, ADA, Beta-NGF, CD40, IL-10RB, CCL19, TGF-alpha, SIRT2, TWEAK, SCF, CSF-1, 4E-BP1, DNER, LIF-R, STAMPB, CXCL10, CXCL6, VEGF-A and CX3CL1). This study reveals a clear effect of BMI on cytokine and chemokine levels in cerebrospinal fluid.
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Affiliation(s)
- Anders Larsson
- Department of Medical Sciences, Uppsala University, SE-751 85 Uppsala, Sweden.
| | - Lena Carlsson
- Department of Medical Sciences, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Anne-Li Lind
- Department of Surgical Sciences, Anesthesiology and Intensive Care and Uppsala Berzelii Technology Center for Neurodiagnostics, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Torsten Gordh
- Department of Surgical Sciences, Anesthesiology and Intensive Care and Uppsala Berzelii Technology Center for Neurodiagnostics, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Constantin Bodolea
- Department of Anaesthesia and Intensive Care, University of Cluj Napoca, Romania
| | - Masood Kamali-Moghaddam
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, SE-751 08 Uppsala, Sweden
| | - Måns Thulin
- Department of Statistics, Uppsala University, SE-751 05 Uppsala, Sweden
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Dörr A, Kress E, Podschun R, Pufe T, Tauber SC, Brandenburg LO. Intrathecal application of the antimicrobial peptide CRAMP reduced mortality and neuroinflammation in an experimental model of pneumococcal meningitis. J Infect 2015; 71:188-99. [PMID: 25896094 DOI: 10.1016/j.jinf.2015.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/23/2015] [Accepted: 04/10/2015] [Indexed: 12/23/2022]
Abstract
Antimicrobial peptides (AP) are important components of the innate immune system. Our previous work revealed a higher mortality rate and up-regulation of proinflammatory gene expression as well as glial cell activation in cathelicidin-related antimicrobial peptide (CRAMP)-deficient mice after bacterial meningitis. However, the influence of CRAMP application on the progression of inflammation and its impact on mortality after bacterial meningitis remains unknown. To assess the effects of continuous CRAMP exposure in the brain, C57BL/6 wildtype mice were given intracerebroventricular infusion of CRAMP to investigate the effects on mortality, glial cell activation and inflammation in a mouse model of pneumococcal meningitis using immunohistochemistry and realtime RT-PCR. Our results revealed a decrease of mortality after CRAMP infusion. The intrathecal CRAMP infusion after pneumococcal meningitis resulted in a decreased mRNA expression of pro-inflammatory cytokines, whereas the immune responses including the expression of pattern recognition receptors and chemokines were increased in bacterial meningitis. Taken together, the results support the important role of CRAMP as part of the innate immune response against pathogens in bacterial CNS infections. The APs may be a promising approach for the development of an adjuvant therapy for bacterial meningitis.
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Affiliation(s)
- Arndt Dörr
- Department of Anatomy and Cell Biology, RWTH Aachen University, Germany
| | - Eugenia Kress
- Department of Anatomy and Cell Biology, RWTH Aachen University, Germany
| | - Rainer Podschun
- Institute for Infection Medicine, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Thomas Pufe
- Department of Anatomy and Cell Biology, RWTH Aachen University, Germany
| | - Simone C Tauber
- Department of Neurology, RWTH University Hospital Aachen, Germany
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Huber AK, Duncker PC, Irani DN. Immune responses to non-tumor antigens in the central nervous system. Front Oncol 2014; 4:328. [PMID: 25431758 PMCID: PMC4230036 DOI: 10.3389/fonc.2014.00328] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/30/2014] [Indexed: 12/16/2022] Open
Abstract
The central nervous system (CNS), once viewed as an immune-privileged site protected by the blood-brain barrier (BBB), is now known to be a dynamic immunological environment through which immune cells migrate to prevent and respond to events such as localized infection. During these responses, endogenous glial cells, including astrocytes and microglia, become highly reactive and may secrete inflammatory mediators that regulate BBB permeability and recruit additional circulating immune cells. Here, we discuss the various roles played by astrocytes, microglia, and infiltrating immune cells during host immunity to non-tumor antigens in the CNS, focusing first on bacterial and viral infections, and then turning to responses directed against self-antigens in the setting of CNS autoimmunity.
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Affiliation(s)
- Amanda K Huber
- Department of Neurology, University of Michigan Medical School , Ann Arbor, MI , USA
| | - Patrick C Duncker
- Department of Neurology, University of Michigan Medical School , Ann Arbor, MI , USA
| | - David N Irani
- Department of Neurology, University of Michigan Medical School , Ann Arbor, MI , USA
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Predictive value of decoy receptor 3 in postoperative nosocomial bacterial meningitis. Int J Mol Sci 2014; 15:19962-70. [PMID: 25372942 PMCID: PMC4264149 DOI: 10.3390/ijms151119962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/28/2014] [Accepted: 10/22/2014] [Indexed: 11/28/2022] Open
Abstract
Nosocomial bacterial meningitis requires timely treatment, but what is difficult is the prompt and accurate diagnosis of this disease. The aim of this study was to assess the potential role of decoy receptor 3 (DcR3) levels in the differentiation of bacterial meningitis from non-bacterial meningitis. A total of 123 patients were recruited in this study, among them 80 patients being with bacterial meningitis and 43 patients with non-bacterial meningitis. Bacterial meningitis was confirmed by bacterial culture of cerebrospinal fluid (CSF) culture and enzyme-linked immunosorbent assay (ELISA) was used to detect the level of DcR3 in CSF. CSF levels of DcR3 were statistically significant between patients with bacterial meningitis and those with non-bacterial meningitis (p < 0.001). A total of 48.75% of patients with bacterial meningitis received antibiotic >24 h before CSF sampling, which was much higher than that of non-bacterial meningitis. CSF leucocyte count yielded the highest diagnostic value, with an area under the receiver operating characteristic curve (ROC) of 0.928, followed by DcR3. At a critical value of 0.201 ng/mL for DcR3, the sensitivity and specificity were 78.75% and 81.40% respectively. DcR3 in CSF may be a valuable predictor for differentiating patients with bacterial meningitis from those with non-bacterial meningitis. Further studies are needed for the validation of this study.
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Coutinho LG, Christen S, Bellac CL, Fontes FL, Souza FRSD, Grandgirard D, Leib SL, Agnez-Lima LF. The kynurenine pathway is involved in bacterial meningitis. J Neuroinflammation 2014; 11:169. [PMID: 25274277 PMCID: PMC4189685 DOI: 10.1186/s12974-014-0169-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial meningitis (BM) is characterized by an intense host inflammatory reaction, which contributes to the development of brain damage and neuronal sequelae. Activation of the kynurenine (KYN) pathway (KP) has been reported in various neurological diseases as a consequence of inflammation. Previously, the KP was shown to be activated in animal models of BM, and the association of the SNP AADAT + 401C/T (kynurenine aminotransferase II - KAT II) with the host immune response to BM has been described. The aim of this study was to investigate the involvement of the KP during BM in humans by assessing the concentrations of KYN metabolites in the cerebrospinal fluid (CSF) of BM patients and their relationship with the inflammatory response compared to aseptic meningitis (AM) and non-meningitis (NM) groups. METHODS The concentrations of tryptophan (TRP), KYN, kynurenic acid (KYNA) and anthranilic acid (AA) were assessed by HPLC from CSF samples of patients hospitalized in the Giselda Trigueiro Hospital in Natal (Rio Grande do Norte, Brazil). The KYN/TRP ratio was used as an index of indoleamine 2,3-dioxygenase (IDO) activity, and cytokines were measured using a multiplex cytokine assay. The KYNA level was also analyzed in relation to AADAT + 401C/T genotypes. RESULTS In CSF from patients with BM, elevated levels of KYN, KYNA, AA, IDO activity and cytokines were observed. The cytokines INF-γ and IL-1Ra showed a positive correlation with IDO activity, and TNF-α and IL-10 were positively correlated with KYN and KYNA, respectively. Furthermore, the highest levels of KYNA were associated with the AADAT + 401 C/T variant allele. CONCLUSION This study suggests a downward modulatory effect of the KP on CSF inflammation during BM.
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Argon gas: a potential neuroprotectant and promising medical therapy. Med Gas Res 2014; 4:3. [PMID: 24533741 PMCID: PMC3996095 DOI: 10.1186/2045-9912-4-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 02/11/2014] [Indexed: 12/16/2022] Open
Abstract
Argon is a noble gas element that has demonstrated narcotic and protective abilities that may prove useful in the medical field. The earliest records of argon gas have exposed its ability to exhibit narcotic symptoms at hyperbaric pressures greater than 10 atmospheres with more recent evidence seeking to display argon as a potential neuroprotective agent. The high availability and low cost of argon provide a distinct advantage over using similarly acting treatments such as xenon gas. Argon gas treatments in models of brain injury such as in vitro Oxygen-Glucose-Deprivation (OGD) and Traumatic Brain Injury (TBI), as well as in vivo Middle Cerebral Artery Occlusion (MCAO) have largely demonstrated positive neuroprotective behavior. On the other hand, some warning has been made to potential negative effects of argon treatments in cases of ischemic brain injury, where increases of damage in the sub-cortical region of the brain have been uncovered. Further support for argon use in the medical field has been demonstrated in its use in combination with tPA, its ability as an organoprotectant, and its surgical applications. This review seeks to summarize the history and development of argon gas use in medical research as mainly a neuroprotective agent, to summarize the mechanisms associated with its biological effects, and to elucidate its future potential.
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