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Jiang M, Chen ZG, Li H, Zhang TT, Yang MJ, Peng XX, Peng B. Succinate and inosine coordinate innate immune response to bacterial infection. PLoS Pathog 2022; 18:e1010796. [PMID: 36026499 PMCID: PMC9455851 DOI: 10.1371/journal.ppat.1010796] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 09/08/2022] [Accepted: 08/04/2022] [Indexed: 12/17/2022] Open
Abstract
Macrophages restrict bacterial infection partly by stimulating phagocytosis and partly by stimulating release of cytokines and complement components. Here, we treat macrophages with LPS and a bacterial pathogen, and demonstrate that expression of cytokine IL-1β and bacterial phagocytosis increase to a transient peak 8 to 12 h post-treatment, while expression of complement component 3 (C3) continues to rise for 24 h post-treatment. Metabolomic analysis suggests a correlation between the cellular concentrations of succinate and IL-1β and of inosine and C3. This may involve a regulatory feedback mechanism, whereby succinate stimulates and inosine inhibits HIF-1α through their competitive interactions with prolyl hydroxylase. Furthermore, increased level of inosine in LPS-stimulated macrophages is linked to accumulation of adenosine monophosphate and that exogenous inosine improves the survival of bacterial pathogen-infected mice and tilapia. The implications of these data suggests potential therapeutic tools to prevent, manage or treat bacterial infections.
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Affiliation(s)
- Ming Jiang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, People’s Republic of China
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, People’s Republic of China
| | - Zhuang-gui Chen
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
| | - Hui Li
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
| | - Tian-tuo Zhang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
| | - Man-jun Yang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
| | - Xuan-xian Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
| | - Bo Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, People’s Republic of China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, People’s Republic of China
- * E-mail:
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Livson S, Virtanen S, Lokki AI, Holster T, Rahkonen L, Kalliala I, Nieminen P, Salonen A, Meri S. Cervicovaginal Complement Activation and Microbiota During Pregnancy and in Parturition. Front Immunol 2022; 13:925630. [PMID: 35958597 PMCID: PMC9358961 DOI: 10.3389/fimmu.2022.925630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/23/2022] [Indexed: 11/24/2022] Open
Abstract
Background Vaginal microbiome and the local innate immune defense, including the complement system, contribute to anti- and proinflammatory homeostasis during pregnancy and parturition. The relationship between commensal vaginal bacteria and complement activation during pregnancy and delivery is not known. Objective To study the association of the cervicovaginal microbiota composition to activation and regulation of the complement system during pregnancy and labor. Study design We recruited women during late pregnancy (weeks 41 + 5 to 42 + 0, n=48) and women in active labor (weeks 38 + 4 to 42 + 2, n=25). Mucosal swabs were taken from the external cervix and lateral fornix of the vagina. From the same sampling site, microbiota was analyzed with 16S RNA gene amplicon sequencing. A Western blot technique was used to detect complement C3, C4 and factor B activation and presence of complement inhibitors. For semiquantitative analysis, the bands of the electrophoresed proteins in gels were digitized on a flatbed photo scanner and staining intensities were analyzed using ImageJ/Fiji win-64 software. Patient data was collected from medical records and questionnaires. Results The vaginal microbiota was Lactobacillus-dominant in most of the samples (n=60), L. iners and L. crispatus being the dominant species. L. gasseri and L. jensenii were found to be more abundant during pregnancy than active labor. L. jensenii abundance correlated with C4 activation during pregnancy but not in labor. Gardnerella vaginalis was associated with C4 activation both during pregnancy and labor. The amount of L. gasseri correlated with factor B activation during pregnancy but not during labor. Atopobium vaginae was more abundant during pregnancy than labor and correlated with C4 activation during labor and with factor B activation during pregnancy. Activation of the alternative pathway factor B was significantly stronger during pregnancy compared to labor. During labor complement activation may be inhibited by the abundant presence of factor H and FHL1. Conclusions These results indicate that bacterial composition of the vaginal microbiota could have a role in the local activation and regulation of complement-mediated inflammation during pregnancy. At the time of parturition complement activation appears to be more strictly regulated than during pregnancy.
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Affiliation(s)
- Sivan Livson
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- *Correspondence: Sivan Livson,
| | - Seppo Virtanen
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - A. Inkeri Lokki
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Tiina Holster
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Leena Rahkonen
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Ilkka Kalliala
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Pekka Nieminen
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anne Salonen
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Hospital District of Helsinki and Uusimaa (HUS) Diagnostic Center, Hospital District of Helsinki and Uusimaa laboratorio (HUSLAB), Helsinki University Hospital Laboratory, Helsinki, Finland
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3
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You MW, Kim D, Lee EH, Park DC, Lee JM, Kang DW, Kim SH, Yeo SG. The Roles of NOD-like Receptors in Innate Immunity in Otitis Media. Int J Mol Sci 2022; 23:ijms23042350. [PMID: 35216465 PMCID: PMC8879371 DOI: 10.3390/ijms23042350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/08/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023] Open
Abstract
Acute otitis media (AOM) can persist or lead to various complications in individuals in which the innate immune system is impaired. In this context, impaired expression of nucleotide-binding oligomerization domain (NOD)-like receptor (NLR), an intracellular pathogen-recognition receptor (PRR), is involved in the etiology of OM in humans and animals, affecting its development, severity, chronicity, recurrence, and associated complications. To assess this relationship, we reviewed literature reports relating NLR expression patterns with the pathophysiology and clinical features of OM in the larger context of impaired innate immunity. We summarized the results of published studies on the expression of NLRs in animals and humans in acute otitis media (AOM), otitis media with effusion (OME), chronic otitis media (COM) with cholesteatoma, and COM without cholesteatoma. NLRs were expressed mainly in association with bacterial infection in AOM, OME, COM with cholesteatoma, and COM without cholesteatoma. In addition, expression of NLRs was affected by the presence or absence of bacteria, fluid characteristics, disease recurrence, tissue type, and repeated surgery. Various factors of the innate immune system are involved in the pathogenesis of OM in the middle ear. NLRs are expressed in AOM, OME, COM with cholesteatoma, and COM without cholesteatoma. Impaired NLR expression induced the development, chronicity and recurrence of OM and exacerbated associated complications, indicating that NLRs have important roles in the pathogenesis of OM.
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Affiliation(s)
- Myung-Won You
- Department of Radiology, College of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Eun-Hye Lee
- Department of Pediatrics, College of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Dong-Choon Park
- St. Vincent’s Hospital, The Catholic University of Korea, Suwon 16247, Korea;
| | - Jae-Min Lee
- Department of Otorhinolaryngology—Head and Neck Surgery, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (J.-M.L.); (D.-W.K.); (S.-H.K.)
| | - Dae-Woong Kang
- Department of Otorhinolaryngology—Head and Neck Surgery, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (J.-M.L.); (D.-W.K.); (S.-H.K.)
| | - Sang-Hoon Kim
- Department of Otorhinolaryngology—Head and Neck Surgery, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (J.-M.L.); (D.-W.K.); (S.-H.K.)
| | - Seung-Geun Yeo
- Department of Otorhinolaryngology—Head and Neck Surgery, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (J.-M.L.); (D.-W.K.); (S.-H.K.)
- Correspondence: ; Tel.: +82-2-958-8474; Fax: +82-2-958-8470
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Livson S, Jarva H, Kalliala I, Lokki AI, Heikkinen-Eloranta J, Nieminen P, Meri S. Activation of the Complement System in the Lower Genital Tract During Pregnancy and Delivery. Front Immunol 2021; 11:563073. [PMID: 33505390 PMCID: PMC7829332 DOI: 10.3389/fimmu.2020.563073] [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: 05/17/2020] [Accepted: 11/24/2020] [Indexed: 12/29/2022] Open
Abstract
Background Human pregnancy alters profoundly the immune system. The local involvement and mechanisms of activation of the complement system in the cervicovaginal milieu during pregnancy and delivery remain unexplored. Objectives To determine whether normal pregnancy and delivery are associated with local activation of complement or changes in the immunoglobulin profile in the cervix. Study Design This study was designed to assess IgA, IgG, and complement activation in the cervicovaginal area in three groups of patients: i) 49 pregnant women (week 41+3–42+0) not in active labor, ii) 24 women in active labor (38+4–42+2), and iii) a control group of nonpregnant women (n=23) at child-bearing age. We collected mucosal samples from the lateral fornix of the vagina and external cervix during routine visits and delivery. The Western blot technique was used to detect complement C3 and its activation products. For semiquantitative analysis, the bands of the electrophoresed proteins in gels were digitized on a flatbed photo scanner and analyzed. IgA and IgG were analyzed by Western blotting and quantified by ELISA. One-way ANOVA and Tukey’s Multiple Comparison tests were used for statistical comparisons. Results A higher abundance but lower activation level of C3 in both the external cervix (P<0.001) and lateral fornix of the vagina (P<0.001) was observed during delivery (58 ± 22, n= 24) in comparison to the groups of nonpregnant (72 ± 13%; mean ± SD, n=23) and pregnant women (78 ± 22%, n=49). Complement activating IgG was detected in higher abundance than IgA in the cervicovaginal secretions of pregnant women. In a small proportion samples also C3-IgG complexes were detected. Conclusions Our results reveal an unexpectedly strong activation of the complement system and the presence IgG immunoglobulins in the cervicovaginal area during pregnancy, active labor, and among nonpregnant women. In contrast to the higher amounts of C3 in the cervicovaginal secretions during labor, its activation level was lower. Complement activating IgG was detected in higher concentrations than IgA in the mucosal secretions during pregnancy and labor. Taken together our results imply the presence a locally operating humoral immune system in the cervicovaginal mucosa.
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Affiliation(s)
- Sivan Livson
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.,Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Hanna Jarva
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland.,HUS Diagnostic Center, Helsinki University Hospital Laboratory, Helsinki University Hospital, Helsinki, Finland
| | - Ilkka Kalliala
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.,Department of Surgery and Cancer, Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom.,Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - A Inkeri Lokki
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.,Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Jenni Heikkinen-Eloranta
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Pekka Nieminen
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.,Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland.,HUS Diagnostic Center, Helsinki University Hospital Laboratory, Helsinki University Hospital, Helsinki, Finland
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5
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Liu S, Guo L, Chen M, Liu W, Li Y, Wang X, Li S, Zhang J, Ni X. Evaluation of Caspase-1, Interleukin-1β, and Interleukin-18, in the Middle Ear Effusion in Children With Otitis Media With Effusion. Front Pediatr 2021; 9:732973. [PMID: 34805037 PMCID: PMC8602791 DOI: 10.3389/fped.2021.732973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/11/2021] [Indexed: 12/15/2022] Open
Abstract
Objectives: The present study aimed to assess the expression of caspase-1 and caspase-1-dependent processing of cytokines, such as interleukin (IL)-1β and IL-18, in the middle ear effusion of children with otitis media with effusion (OME) in order to identify the potential role of inflammasomes in OME. Methods: This study included 29 children scheduled for myringotomy with the insertion of tympanostomy tubes due to OME. Middle ear effusion (MEE) was collected during the surgery. Caspase-1, IL-1β, and IL-18 were assayed using enzyme-linked immunosorbent assay kits. The levels were compared between those with mucoid and serous MEE and those with and without a history of ventilation tube insertion. Results: Caspase-1, IL-1β, and IL-18 were detected in all samples. The caspase-1, IL-1β, and IL-18 levels did not significantly differ between mucoid samples and serous samples. No statistical significances were discovered in caspase-1, IL-1β, and IL-18 levels between with and without a history of ventilation tube groups. There was a significant negative correlation between IL-1β and IL-18 and the duration of OME (p < 0.05). However, no significant correlation was found between caspase-1 and disease duration. Conclusions: Inflammasomes may participate in the inflammatory process of OME. IL-1β and IL-18 levels in the MEE decreased over time.
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Affiliation(s)
- Shanshan Liu
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Lining Guo
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Min Chen
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Wei Liu
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Yanhong Li
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Xiaoxu Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Shilan Li
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Jie Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
| | - Xin Ni
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery, Beijing, China
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6
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Ryan AF, Juhn SK, Andalibi A, Bakaletz LO, Ehrlich GD, Jung TTK, Li JD, Lin J, Post CJ. 4A. Molecular Biology. Ann Otol Rhinol Laryngol 2016. [DOI: 10.1177/00034894051140s106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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Ryan AF, Juhn SK, Andalibi A, Bakaletz LO, Ehrlich GD, Jung TTK, Li JD, Lin J, Post CJ. 4B. Biochemistry. Ann Otol Rhinol Laryngol 2016. [DOI: 10.1177/00034894051140s107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Abstract
The ongoing childhood obesity epidemic has garnered significant attention among healthcare providers due to its short- and long-term sequelae. Multiple diseases have been associated with obesity, not limited to hypertension, diabetes, and attention deficit hyperactivity disorder. Over the past decade, the relationships between obesity and otologic conditions have been investigated. In this setting, otitis media has remained the focus of research, representing one of the most common pediatric illnesses. Initial studies suggesting a relationship between the two conditions have been supported with epidemiological studies controlling for socioeconomic factors. The purpose of this article is to review our current understanding of the relationship between otitis media and obesity and to discuss the healthcare implications of this association. In addition, several identifiable factors associated with each condition are discussed, as are potential pathophysiologic mechanisms that may help to elucidate the complex and multifactorial relationship between the two disease entities.
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Affiliation(s)
- Sameer Ahmed
- Department of Head and Neck Surgery, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
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9
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Tong HH, Lambert G, Li YX, Thurman JM, Stahl GL, Douthitt K, Clancy C, He Y, Bowman AS. Deletion of the complement C5a receptor alleviates the severity of acute pneumococcal otitis media following influenza A virus infection in mice. PLoS One 2014; 9:e95160. [PMID: 24740152 PMCID: PMC3989264 DOI: 10.1371/journal.pone.0095160] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 03/24/2014] [Indexed: 12/04/2022] Open
Abstract
There is considerable evidence that influenza A virus (IAV) promotes adherence, colonization, and superinfection by S. pneumoniae (Spn) and contributes to the pathogenesis of otitis media (OM). The complement system is a critical innate immune defense against both pathogens. To assess the role of the complement system in the host defense and the pathogenesis of acute pneumococcal OM following IAV infection, we employed a well-established transtympanically-induced mouse model of acute pneumococcal OM. We found that antecedent IAV infection enhanced the severity of acute pneumococcal OM. Mice deficient in complement C1qa (C1qa−/−) or factor B (Bf −/−) exhibited delayed viral and bacterial clearance from the middle ear and developed significant mucosal damage in the eustachian tube and middle ear. This indicates that both the classical and alternative complement pathways are critical for the oto-immune defense against acute pneumococcal OM following influenza infection. We also found that Spn increased complement activation following IAV infection. This was characterized by sustained increased levels of anaphylatoxins C3a and C5a in serum and middle ear lavage samples. In contrast, mice deficient in the complement C5a receptor (C5aR) demonstrated enhanced bacterial clearance and reduced severity of OM. Our data support the concept that C5a-C5aR interactions play a significant role in the pathogenesis of acute pneumococcal OM following IAV infection. It is possible that targeting the C5a-C5aR axis might prove useful in attenuating acute pneumococcal OM in patients with influenza infection.
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Affiliation(s)
- Hua Hua Tong
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, United States of America
| | - Garrett Lambert
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, United States of America
| | - Yong Xing Li
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, United States of America
| | - Joshua M Thurman
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Gregory L Stahl
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kelsey Douthitt
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, United States of America
| | - Caitlin Clancy
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, United States of America
| | - Yujuan He
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, United States of America; Department of Clinical Laboratory Medicine, Chongqing Medical University, Chongqing, Sichuan, P. R. China
| | - Andrew S Bowman
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
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10
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Chantzi FM, Bairamis T, Papadopoulos NG, Kafetzis DA. Otitis media with effusion: an effort to understand and clarify the uncertainties. Expert Rev Anti Infect Ther 2014; 3:117-29. [PMID: 15757462 DOI: 10.1586/14787210.3.1.117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Otitis media with effusion--defined as the accumulation of middle-ear effusion behind an intact tympanic membrane without signs or symptoms of acute infection--is one of the most common causes of hearing loss in children in developed countries, potentially leading to language deficits. Although treatment of chronic or relapsing otitis media with effusion is considered imperative, none of the preventative or nonsurgical management measures currently available have proven effective. Tympanostomy tube placement remains the recommended treatment option for high-risk children or for cases of unresponsive otitis media with effusion. This can be attributed to the uncertainties surrounding its pathogenesis. Multiple factors and several possible pathogenetic models have been proposed to explain the production and persistence of middle-ear effusion; only a few of them are supported by sufficient evidence. In this review, the authors will present current knowledge on the pathogenesis, consequences, diagnosis and management of otitis media with effusion. An effort will be made to clarify those aspects sufficiently supported by evidence-based studies, and to underline those that remain unfounded.
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Affiliation(s)
- Fotini-Maria Chantzi
- University of Athens, Second Department of Pediatrics, and the ENT department, P and A Kyriakou Children's Hospital, Athens 115 27, Greece
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11
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Outer membrane protein P5 is required for resistance of nontypeable Haemophilus influenzae to both the classical and alternative complement pathways. Infect Immun 2013; 82:640-9. [PMID: 24478079 DOI: 10.1128/iai.01224-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The complement system is an important first line of defense against the human pathogen Haemophilus influenzae. To survive and propagate in vivo, H. influenzae has evolved mechanisms for subverting this host defense, most of which have been shown to involve outer surface structures, including lipooligosaccharide glycans and outer surface proteins. Bacterial defense against complement acts at multiple steps in the pathway by mechanisms that are not fully understood. Here we identify outer membrane protein P5 as an essential factor in serum resistance of both H. influenzae strain Rd and nontypeable H. influenzae (NTHi) clinical isolate NT127. P5 was essential for resistance of Rd and NT127 to complement in pooled human serum. Further investigation determined that P5 expression decreased cell surface binding of IgM, a potent activator of the classical pathway of complement, to both Rd and NT127. Additionally, P5 expression was required for NT127 to bind factor H (fH), an important inhibitor of alternative pathway (AP) activation. Collectively, the results obtained in this work highlight the ability of H. influenzae to utilize a single protein to perform multiple protective functions for evading host immunity.
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12
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He Y, Scholes MA, Wiet GJ, Li Q, Clancy C, Tong HH. Complement activation in pediatric patients with recurrent acute otitis media. Int J Pediatr Otorhinolaryngol 2013; 77:911-7. [PMID: 23537925 PMCID: PMC3660544 DOI: 10.1016/j.ijporl.2013.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 01/31/2013] [Accepted: 03/02/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Otitis media (OM) is one of the most common childhood diseases. The relative contribution of complement activation in protection and pathogenesis during OM remains largely unknown. The purpose of this study was to investigate the beneficial and pathogenic contributions of complement activation in the middle ear of pediatric patients with recurrent acute otitis media (rAOM), and therefore to provide a rational approach to prevent sequelae of OM such as hearing loss. METHODS Twenty children undergoing pressure equalization tube placement with or without adenoidectomy for rAOM were enrolled in the study. Bacterial cultures, enzyme-linked immunosorbent assay (ELISA) for complement components and cytokines and western blot for complement activation were performed on middle ear effusion (MEE) and serum samples. The levels of complement C3a, C5a and sC5-b9 in MEEs and serum samples were compared. The levels of these factors were also examined in regards to length of episode. Pearson's correlation coefficients were calculated on variables between C5a and IL-6 or IL-8. Complement gene expression in human middle ear epithelial (HMEE) cells induced by otopathogens was evaluated. Data were analyzed with Student's t test or the Mann-Whitney rank sum test. In all cases, a P value of <0.05 was set as the measure of significance. RESULTS Our data demonstrated that the complement classical/lectin, alternative and terminal pathways were activated in the middle ear of children with rAOM. Increased complement components of C3a, C5a and sC5-b9 in MEEs were detected in patients with the episode lasting more than six weeks. There was a strong correlation between C5a and IL-6 or IL-8 in the MEEs. Additionally, otopathogens induced enhanced gene expression of factor B and C3 in HMEE cells, which is beneficial for host defense against invading pathogens. CONCLUSION Our studies provided important new insights on how complement activation contributes to inflammatory process during rAOM. Knowledge of the activity of the complement pathway in patients with rAOM may stimulate the development of new strategies to prevent middle ear inflammatory tissue destruction by directing treatment to specific pathways within the complement cascade.
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Affiliation(s)
- Yujuan He
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210, USA
- Department of Clinical Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Melissa A. Scholes
- Department of Otolaryngology, Nationwide Children’s Hospital, Columbus, OH
| | - Gregory J. Wiet
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210, USA
- Department of Otolaryngology, Nationwide Children’s Hospital, Columbus, OH
| | - Qian Li
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210, USA
- Department of Infectious Diseases, FuDan University affiliated Hua Shan Hospital, Shanghai, China
| | - Caitlin Clancy
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210, USA
| | - Hua Hua Tong
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210, USA
- Corresponding author Mailing address: The Ohio State University, Department of Otolaryngology-Head and Neck Surgery, 4024 Cramblett Hall, Columbus, OH 43210, Phone: 614-293-8103, Fax: 614-293-5506,
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Hallström T, Riesbeck K. Haemophilus influenzae and the complement system. Trends Microbiol 2010; 18:258-65. [PMID: 20399102 DOI: 10.1016/j.tim.2010.03.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 03/10/2010] [Accepted: 03/17/2010] [Indexed: 02/04/2023]
Abstract
The respiratory tract pathogen Haemophilus influenzae is responsible for a variety of infections in humans including septicemia, bronchitis, pneumonia, and acute otitis media. The pathogenesis of H. influenzae relies on its capacity to resist human host defenses including the complement system, and thus H. influenzae has developed several efficient strategies to circumvent complement attack. In addition to attracting specific host complement regulators directly to the bacterial surface, the capsule, lipooligosaccharides, and several outer membrane proteins contribute to resistance against complement-mediated attacks and hence increased bacterial survival. Insights into the mechanisms of complement evasion by H. influenzae are important for understanding pathogenesis and for developing vaccines and new therapies aimed at patients with, for example, chronic obstructive pulmonary disease. Here we overview current knowledge on the different mechanisms by which H. influenzae evades attack by the host complement system.
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Affiliation(s)
- Teresia Hallström
- Medical Microbiology, Department of Laboratory Medicine Malmö, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden
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Expression of HSP70 and Its Relation with Other Cytokines in Human Middle Ear Effusion. Clin Exp Otorhinolaryngol 2010; 3:18-23. [PMID: 20379397 PMCID: PMC2848313 DOI: 10.3342/ceo.2010.3.1.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 11/26/2009] [Indexed: 11/30/2022] Open
Abstract
Objectives While other cytokines are known to be associated with otitis media with effusion (OME), the involvement of heat shock protein 70 (HSP70) in middle ear effusion (MEE) is unknown. This study was undertaken to investigate the possibility of there being a HSP70 expression in human MEE and to determine its potential role as a cytokine in OME. Methods The levels of HSP70, tumor necrosis factor-alpha and interleukin-1beta were measured by enzyme-linked immunosorbent assay in the effusion of different groups of OME patient following collection of the MEE using our new collection system. The clinical characteristics of the OME patients and the MEE status were analyzed. Results HSP70 was expressed in all the types of MEE. The mucous and seromucous effusions showed higher HSP70 levels than that of the serous effusion. The HSP70 level was correlated with the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the effusions. The positive correlations between HSP70, TNF-α and IL-1β were statistically significant (P<0.05). Conclusion The highly elevated level of HSP70 in the seromucous and mucous effusions implicates this protein in the chronicity of OME.
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Proinflammatory and immunoregulatory cytokines in the middle ear effusions. Int J Pediatr Otorhinolaryngol 2008; 72:13-7. [PMID: 17976828 DOI: 10.1016/j.ijporl.2007.09.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 09/03/2007] [Accepted: 09/05/2007] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The recognition of inflammatory mediators in middle ear effusions and their correlation with clinical parameters may allow better understanding of many complex events leading to development of permanent sequelae of otitis media and hopefully help to develop future interventions. The aim of the study was to evaluate the presence and level of proinflammatory interleukin (IL) 1beta, IL-6 and immunoregulatory IL-10 in the middle ear effusions, their mutual correlation and relationship with age, duration of the illness, number of episodes of acute otitis media, and presence of retraction pockets. METHODS The study included 25 children (41 ears), who had been scheduled for myringotomy with the insertion of tympanostomy tubes due to otitis media with effusion. The interview (duration of the illness, number of episodes of acute otitis media), clinical and audiological examination was conducted according to the developed examination check list. Middle ear effusions (MEE) were collected aseptically, the samples centrifuged and supernatant frozen at a temperature of -80 degrees C. The IL-1beta, IL-6 and IL-10 were assayed using enzyme-linked immunosorbent assay (ELISA) kits incorporating monoclonal antibodies and the ETI system reader. The nonparametric Mann-Whitney U test was used for statistical analysis and Pearson's linear correlation coefficient was calculated. RESULTS IL-1beta was detected in 80% of examined effusions, IL-6 in 78%, and IL-10 in 88%. There was a strong statistical correlation between IL-1beta and IL-6 concentrations (r=0.627, P=0.000), as well as IL-6 and IL-10 (r=0.66, P=0.000) No statistically significant correlation was found between levels of cytokines and clinical parameters. CONCLUSIONS Proinflammatory and immunoregulatory cytokines participate in middle ear inflammatory response. The lack of direct correlation between IL-1beta and IL-10 may be responsible for chronic character of the disease. As no correlation between the levels of cytokines and clinical parameters was found it seems that the time of duration of inflammation rather than its intensity measured by levels of cytokines is the main factor in development of middle ear mucosa pathology.
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Rezes S, Késmárki K, Sipka S, Sziklai I. Characterization of otitis media with effusion based on the ratio of albumin and immunoglobulin G concentrations in the effusion. Otol Neurotol 2007; 28:663-7. [PMID: 17667774 DOI: 10.1097/01.mao.0000281798.28950.ac] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To characterize the groups of middle ear effusions (MEE) defined on the basis of the ratio of albumin and immunoglobulin G concentrations (A/G) in the effusion and to identify the correlation between these groups of MEE and the clinical features of otitis media with effusion (OME). STUDY DESIGN A laboratory analysis of 88 samples of MEE and a retrospective analysis of the medical history of all patients was performed. SETTING Tertiary referral center. PATIENTS Thirty-three girls and 23 boys with OME were included in the study. INTERVENTION The concentrations of albumin, immunoglobulins (IgG, IgA, and IgM), complement factors (C3, C4), and C-reactive protein were determined by means of nephelometry. Enzyme-linked immunosorbent assay was used to measure cytokines interferon-gamma, tumor necrosis factor alpha, interleukin (IL)-4, and IL-10 concentrations. Groups were defined according to A/G ratio in the effusions. Thirty-five children underwent allergy testing. MAIN OUTCOME MEASURE Two groups of MEE could be recognized on the basis of A/G ratio; the ratio was lower than 0.7 in group A and was higher than 0.7 in group B. RESULTS Increased levels of interferon-gamma and tumor necrosis factor alpha were observed in group A, whereas IL-4 and IL-10 were dominating in group B. No association was found between the MEE groups and the clinical features of the disease or the atopic status of the patient. CONCLUSION These results suggest that various groups of OME can be categorized according to the differences in A/G ratio in the effusions. These differences can reflect the variances in the pathomechanism of the development of the effusion, the stage of the disease, or the clinical background of the patients.
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Affiliation(s)
- Szilárd Rezes
- Department of Otorhinolaryngology/Head and Neck Surgery, and Autoimmune Research Group of the Hungarian Academy of Sciences, Health Science Center, University of Debrecen, Debrecen, Hungary.
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Smirnova MG, Birchall JP, Pearson JP. The immunoregulatory and allergy-associated cytokines in the aetiology of the otitis media with effusion. Mediators Inflamm 2005; 13:75-88. [PMID: 15203548 PMCID: PMC1781541 DOI: 10.1080/09629350410001688477] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2022] Open
Abstract
Inflammation in the middle ear mucosa, which can be provoked by different primary factors such as bacterial and viral infection, local allergic reactions and reflux, is the crucial event in the pathogenesis of otitis media with effusion (OME). Unresolved acute inflammatory responses or defective immunoregulation of middle inflammation can promote chronic inflammatory processes and stimulate the chronic condition of OME. Cytokines are the central molecular regulators of middle ear inflammation and can switch the acute phase of inflammation in the chronic stage and induce molecular-pathological processes leading to the histopathological changes accompanying OME. In this review we present cytokines identified in otitis media, immunoregulatory [interleukin (IL)-2, IL-10, transforming growth factor-beta]) and allergy associated (IL-4, IL-5, granulocyte-macrophage colony-stimulating factor), as crucial molecular regulators, responsible for chronic inflammation in the middle ear and the chronic condition of OME.
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Affiliation(s)
- Marina G Smirnova
- School of Cell and Molecular Biosciences, University of Newcastle, The Medical School, Framlington Place Newcastle upon Tyne, NE2 4HH, Nottingham, UK.
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Nordahl EA, Rydengård V, Nyberg P, Nitsche DP, Mörgelin M, Malmsten M, Björck L, Schmidtchen A. Activation of the complement system generates antibacterial peptides. Proc Natl Acad Sci U S A 2004; 101:16879-84. [PMID: 15550543 PMCID: PMC534732 DOI: 10.1073/pnas.0406678101] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Accepted: 10/21/2004] [Indexed: 01/19/2023] Open
Abstract
The complement system represents an evolutionary old and significant part of the innate immune system involved in protection against invading microorganisms. Here, we show that the anaphylatoxin C3a and its inactivated derivative C3a-desArg are antibacterial, demonstrating a previously unknown direct antimicrobial effect of complement activation. The C3a peptide, as well as functional epitopes in the sequence, efficiently killed the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and the Gram-positive Enterococcus faecalis. In mice, a C3a-derived peptide suppressed infection by Gram-positive Streptococcus pyogenes bacteria. Fluorescence and electron microscopy demonstrated that C3a binds to and induces breaks in bacterial membranes. C3a was also found to induce membrane leakage of liposomes. These findings provide an interesting link between the complement system and antimicrobial peptides, which are two important branches of innate immunity.
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Affiliation(s)
- Emma Andersson Nordahl
- Department of Dermatology and Venereology, Lund University, Biomedical Center, Tornavägen 10, SE-221 84 Lund, Sweden
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Butler CC, Williams RG. The Etiology, Pathophysiology, and Management of Otitis Media with Effusion. Curr Infect Dis Rep 2003; 5:205-212. [PMID: 12760817 PMCID: PMC7089124 DOI: 10.1007/s11908-003-0075-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Otitis media with effusion (OME) is a common and important condition that may result in developmental delay in children, and significant health care resources are devoted to its management. Newer techniques including polymerase chain reaction are implicating organisms not previously considered important in etiology. The role of gastroesophageal reflux as a cause of OME is likely to receive greater research attention. Regarding prevention, more is being learned about potentially modifiable risk factors such as environmental smoke, care outside the home, and breast feeding. Although immunization may to play a role in the future, existing evidence suggests that the general population of children should not be immunized in order to prevent OME. Several major studies have recently added to the understanding of epidemiology and management. Large trials in the United States, the Netherlands, and the UK suggest that OME is not an appropriate condition to include in a screening program. In addition, the advantages of early treatment with ventilation tubes over watchful waiting in terms of language development tend be modest and diminish by about 18 months. Treatment with hearing aids should be further evaluated. The search for effective medical management continues, and better ways are being identified of targeting interventions to those children with OME who are most likely to benefit.
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Affiliation(s)
- Christopher C. Butler
- *Department of General Practice, University of Wales College of Medicine, Llanedeyrn Health Centre, Cardiff CF23 9PN, UK.
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Jeong HJ, Hong SH, Kim SC, Park EJ, Jang CH, Kim KS, Kim HM. Effects of Allergina on the treatment of otitis media with effusions. Inflammation 2002; 26:89-95. [PMID: 11989792 DOI: 10.1023/a:1014888328482] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The number of pediatric patients with recurrent otitis media with effusions (ROMEs) is increasing because of the frequency of recurrence. The herbal combination Allergina is used for inflammatory-disease treatment in the Republic of Korea; in our study, the patients with ROME were treated with either Allergina (11 ears) or antibiotics (13 ears). We analyzed the levels of cytokines in middle-ear effusions (MEEs) and compared these levels in the Allergina-treated patients with those in the antibiotics-treated patients. The mean levels of interleukin (IL)-2 and IL-4 in MEEs were significantly higher in the Allergina-treated patients than in the antibiotics-treated patients, whereas levels of IL-1beta, IL-6, IL-8, and tumor necrosis factor (TNF)-alpha in MEEs were significantly lower in the Allergina-treated patients than in the antibiotics-treated patients. Clinical signs of ROME disappeared markedly after all the patients were given an oral administration of Allergina. Our experimental studies provide evidence that Allergina may be beneficial in the treatment of ROME by regulating cytokine production.
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Affiliation(s)
- Hyun-Ja Jeong
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Iksan, Chonbuk, Republic of Korea
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Närkiö-Mäkelä M, Hellwage J, Tahkokallio O, Meri S. Complement-regulator factor H and related proteins in otitis media with effusion. Clin Immunol 2001; 100:118-26. [PMID: 11414752 DOI: 10.1006/clim.2001.5043] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Otitis media with effusion (OME) is a common disease in childhood. It is characterized by chronic inflammation in which the proinflammatory activity of the complement (C) system is one of the underlying factors. The C system becomes strongly activated in the middle ear effusion (MEE) fluid, but the reasons for this are not known. Here we demonstrate by using complement Bb fragment ELISA that MEE specimens strongly activate the alternative C pathway (AP) in normal human serum (NHS). Some of the MEEs were also found to promote lysis of rabbit erythrocytes by NHS. These findings indicated a disturbance in the fluid-phase regulation of the AP in MEE. The main regulator of the AP, factor H (FH), and proteins structurally related to it (FHL-1, FHR-1, -2, -3, and -4) were present in the MEE fluids of OME patients. Relative to serum, the FHR proteins were more abundant in the MEEs. In addition, we detected the recently discovered 65-kDa FH-related protein FHR-5 in the MEE. The FHR proteins share binding sites with FH in the C3d region of C3b. Thus they may compete with FH in binding to C3b and interfere with the regulatory activity of FH. Consequently, a disturbance in AP control in the MEE may lead to an ongoing excessive C activation and inflammation in OME.
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Affiliation(s)
- M Närkiö-Mäkelä
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
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Närkiö-Mäkelä M, Meri S. Cytolytic complement activity in otitis media with effusion. Clin Exp Immunol 2001; 124:369-76. [PMID: 11472396 PMCID: PMC1906070 DOI: 10.1046/j.1365-2249.2001.01523.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2001] [Indexed: 11/20/2022] Open
Abstract
Otitis media with effusion (OME) is a chronic inflammation persisting in the middle ear cavity of at least 8 weeks duration. Middle ear effusion (MEE; n = 38), samples from children suffering from OME were investigated for their direct cytolytic activity or an ability to enhance complement lysis of unsensitized bystander cells. Thirteen of the 38 MEEs had direct endogenous haemolytic activity and 27 samples had an ability to enhance serum-initiated lysis. Using an enzyme immunoassay, high levels of terminal complement complexes (TCC) were detected in the MEE samples (mean 34.1 microg/ml, range 5--89 microg/ml). This indicated strong local complement activation that had progressed to the terminal stage. As one potential factor promoting complement activation we identified both monomeric and trimeric properdin in MEE by Western blotting. By stabilizing C3 and C5 convertases properdin accelerates the alternative and terminal pathways of complement. On the other hand, the membrane attack complex (MAC) inhibitor CD59, which was found to be extensively shed into the MEE in a functionally active form, may control excessive cytotoxicity of the MEE. In conclusion, intense complement activation, up to the terminal level, maintains ongoing inflammation in the middle ear cavity and can pose a threat to the local epithelium.
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Affiliation(s)
- M Närkiö-Mäkelä
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Finland
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