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Svärd A, LoMartire R, Martinsson K, Öhman C, Kastbom A, Johansson A. Presence and Immunoreactivity of Aggregatibacter actinomycetemcomitans in Rheumatoid Arthritis. Pathogens 2024; 13:368. [PMID: 38787220 PMCID: PMC11123772 DOI: 10.3390/pathogens13050368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
The presence of periodontal pathogens is associated with an increased prevalence of rheumatoid arthritis (RA). The systemic antibody response to epitopes of these bacteria is often used as a proxy to study correlations between bacteria and RA. The primary aim of the present study is to examine the correlation between the presence of Aggregatibacter actinomycetemcomitans (Aa) in the oral cavity and serum antibodies against the leukotoxin (LtxA) produced by this bacterium. The salivary presence of Aa was analyzed with quantitative PCR and serum LtxA ab in a cell culture-based neutralization assay. The analyses were performed on samples from a well-characterized RA cohort (n = 189) and a reference population of blood donors (n = 101). Salivary Aa was present in 15% of the RA patients and 6% of the blood donors. LtxA ab were detected in 19% of RA-sera and in 16% of sera from blood donors. The correlation between salivary Aa and serum LtxA ab was surprisingly low (rho = 0.55 [95% CI: 0.40, 0.68]). The presence of salivary Aa showed no significant association with any of the RA-associated parameters documented in the cohort. A limitation of the present study is the relatively low number of individuals with detectable concentrations of Aa in saliva. Moreover, in the comparison of detectable Aa prevalence between RA patients and blood donors, we assumed that the two groups were equivalent in other Aa prognostic factors. These limitations must be taken into consideration when the result from the study is interpreted. We conclude that a systemic immune response to Aa LtxA does not fully reflect the prevalence of Aa in saliva. In addition, the association between RA-associated parameters and the presence of Aa was negligible in the present RA cohort.
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Affiliation(s)
- Anna Svärd
- Center for Clinical Research Dalarna, Uppsala University, 791 82 Falun, Sweden; (A.S.); (R.L.)
- Department of Rheumatology, Linköping University Hospital, 581 85 Linköping, Sweden;
| | - Riccardo LoMartire
- Center for Clinical Research Dalarna, Uppsala University, 791 82 Falun, Sweden; (A.S.); (R.L.)
- School of Health and Welfare, Dalarna University, 791 88 Falun, Sweden
| | - Klara Martinsson
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, 581 83 Linköping, Sweden;
| | - Carina Öhman
- Department of Odontology, Umeå University, 901 87 Umeå, Sweden;
| | - Alf Kastbom
- Department of Rheumatology, Linköping University Hospital, 581 85 Linköping, Sweden;
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, 581 83 Linköping, Sweden;
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Virulence Factors of the Periodontal Pathogens: Tools to Evade the Host Immune Response and Promote Carcinogenesis. Microorganisms 2023; 11:microorganisms11010115. [PMID: 36677408 PMCID: PMC9860638 DOI: 10.3390/microorganisms11010115] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023] Open
Abstract
Periodontitis is the most common chronic, inflammatory oral disease that affects more than half of the population in the United States. The disease leads to destruction of the tooth-supporting tissue called periodontium, which ultimately results in tooth loss if uncured. The interaction between the periodontal microbiota and the host immune cells result in the induction of a non-protective host immune response that triggers host tissue destruction. Certain pathogens have been implicated periodontal disease formation that is triggered by a plethora of virulence factors. There is a collective evidence on the impact of periodontal disease progression on systemic health. Of particular interest, the role of the virulence factors of the periodontal pathogens in facilitating the evasion of the host immune cells and promotion of carcinogenesis has been the focus of many researchers. The aim of this review is to examine the influence of the periodontal pathogens Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis), and Fusobacterium nucleatum (F. nucleatum) in the modulation of the intracellular signaling pathways of the host cells in order to evade the host immune response and interfere with normal host cell death and the role of their virulence factors in this regard.
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Effect of Dextranase and Dextranase-and-Nisin-Containing Mouthwashes on Oral Microbial Community of Healthy Adults—A Pilot Study. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study analyzed the alteration of oral microbial composition in healthy subjects after using dextranase-containing mouthwash (DMW; Mouthwash formulation I) and dextranase-and-nisin-containing mouthwash (DNMW; Mouthwash formulation II). Eighteen participants were recruited and were randomly allocated to two groups: G1 (DMW user; n = 8) and G2 (DNMW user; n = 10). The subjects were instructed to use the provided mouthwash regularly twice a day for 30 days. The bleeding on probing (BOP), plaque index (PI), probing depth (PBD), and gingival index (GI) were analyzed, and saliva samples were collected before (day 0) and after (day 30) the use of mouthwashes. The saliva metagenomic DNA was extracted and sequenced (next-generation sequencing, Miseq paired-end Illumina 2 × 250 bp platform). The oral microbial community in the pre-and post-treated samples were annotated using QIIME 2™. The results showed the PI and PBD values were significantly reduced in G2 samples. The BOP and GI values of both groups were not significantly altered. The post-treated samples of both groups yielded a reduced amount of microbial DNA. The computed phylogenetic diversity, species richness, and evenness were reduced significantly in the post-treated samples of G2 compared to the post-treated G1 samples. The mouthwash formulations also supported some pathogens’ growth, which indicated that formulations required further improvement. The study needs further experiments to conclude the results. The study suggested that the improved DNMW could be an adjuvant product to improve oral hygiene.
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Damgaard C, Danielsen AK, Enevold C, Reinholdt J, Holmstrup P, Nielsen CH, Massarenti L. Circulating antibodies against leukotoxin A as marker of periodontitis grades B and C and oral infection with Aggregatibacter actinomycetemcomitans. J Periodontol 2021; 92:1795-1804. [PMID: 33749825 DOI: 10.1002/jper.20-0895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/13/2021] [Accepted: 03/13/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND The facultative bacterium Aggregatibacter actinomycetemcomitans (Aa) is strongly associated with periodontitis and is occasionally found in periodontally healthy subjects. We aimed to determine the prevalence of salivary Aa among patients with either periodontitis grade B (periodontitis-B) or grade C (periodontitis-C), periodontally healthy controls (HCs), and to determine if systemic antibodies against Aa or its virulence factor leukotoxin A (LtxA) may serve as biomarkers that reveal the oral presence of the bacterium and discriminate subjects with periodontitis-C, periodontitis-B, or no periodontitis from each other. METHODS Serum and unstimulated saliva samples were collected from patients with periodontitis-C (n = 27), patients with periodontitis-B (n = 34), and HCs (n = 28). Serum level of immunoglobulin G antibodies to fragmented whole Aa and to LtxA were quantified using a bead-based assay. Aa was identified in saliva using quantitative polymerase chain reaction (qPCR). All analyses were adjusted for age, sex, and current smoking status. RESULTS Aa was present in saliva from 11% of HCs, in 32% of patients with periodontitis-B (P = 0.04 versus HCs), and in 37% of patients with periodontitis-C (P = 0.02 versus HCs). Serum antibodies to fragments of Aa associated significantly with periodontitis-C (P = 0.03), while serum anti-LtxA antibodies associated with both periodontitis-B and periodontitis-C (P = 0.002 and P = 9×10-4 , respectively). Moreover, a significant association between serum anti-LtxA antibodies and Aa count in saliva was observed (P = 0.001). On the basis of serum anti-LtxA antibody levels, patients with periodontitis could be discriminated from HCs (AUC = 0.74 in ROC curve-analysis, P = 0.0003), and carriers of Aa could be discriminated from non-carriers (AUC = 0.78, P <0.0001). CONCLUSIONS Aa is highly prevalent in saliva of patients with periodontitis-B or periodontitis-C. Systemic immunoglobulin G antibodies against LtxA distinguish patients with periodontitis, regardless of grade, from HCs, while their quantity reflects the concurrent bacterial burden in the oral cavity.
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Affiliation(s)
- Christian Damgaard
- Research area Periodontology, Section for Oral Biology & Immunopathology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 20, The Capitol Region, Copenhagen, 2200, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, The Capitol Region, Copenhagen, 2100, Denmark
| | - Anne Katrine Danielsen
- Research area Periodontology, Section for Oral Biology & Immunopathology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 20, The Capitol Region, Copenhagen, 2200, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, The Capitol Region, Copenhagen, 2100, Denmark
| | - Christian Enevold
- Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, The Capitol Region, Copenhagen, 2100, Denmark
| | - Jesper Reinholdt
- Department of Biomedicine, Aarhus University, Høegh-Guldbergs Gade 10, Central Denmark Region, Aarhus, 8000, Denmark
| | - Palle Holmstrup
- Research area Periodontology, Section for Oral Biology & Immunopathology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 20, The Capitol Region, Copenhagen, 2200, Denmark
| | - Claus H Nielsen
- Research area Periodontology, Section for Oral Biology & Immunopathology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 20, The Capitol Region, Copenhagen, 2200, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, The Capitol Region, Copenhagen, 2100, Denmark
| | - Laura Massarenti
- Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, The Capitol Region, Copenhagen, 2100, Denmark
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Zhu Z, He Z, Xie G, Fan Y, Shao T. Altered oral microbiota composition associated with recurrent aphthous stomatitis in young females. Medicine (Baltimore) 2021; 100:e24742. [PMID: 33725829 PMCID: PMC7969233 DOI: 10.1097/md.0000000000024742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 01/22/2021] [Indexed: 01/05/2023] Open
Abstract
Oral microbiota has been implicated in pathogenesis of recurrent aphthous stomatitis (RAS), which is a common mucosal disorder with unclear etiology. This study has explored the association between oral microbiota disorder and RAS in high-risk young female population.Forty-five young females were enrolled, including 24 RAS patients and 21 healthy individuals. Oral microbiome was analyzed by Illumina Miseq sequencing.Oral microbiota associated with RAS was characterized by the lower alpha-diversity indices (Chao1 and ACE). Several infectious pathogens increased in RAS, such as genera Actinobacillus, Haemophilus, Prevotella and Vibrio. The PICRUSt analysis indicated that the oral microbiota might be related with the up-regulation of genes involving infectious and neurodegenerative diseases, environmental adaptation, the down-regulation of genes involving basal metabolism, such as carbohydrate, energy, and amino acid metabolism.This study indicated that oral microbiota may play a significant role in RAS development.
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Affiliation(s)
- Zhengyang Zhu
- The first clinical college, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Zhixing He
- Institute of Basic Research in Clinical Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Guanqun Xie
- Institute of Basic Research in Clinical Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Yongsheng Fan
- Institute of Basic Research in Clinical Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Tiejuan Shao
- Institute of Basic Research in Clinical Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou 310053, China
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Torres MA, Gualtero DF, Lafaurie GI, Fontanilla MR. Aggregatibacter actinomycetemcomitans
induces a proatherosclerotic response in human endothelial cells in a three‐dimensional collagen scaffold model. Mol Oral Microbiol 2020. [DOI: 10.1111/omi.12326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maria A. Torres
- Tissue Engineering Group Department of Pharmacy Universidad Nacional de Colombia Bogotá Colombia
- Biotechnology Laboratory, Basic Oral Research Unit (UIBO) School of Odontology Universidad El Bosque Bogotá Colombia
| | - Diego F. Gualtero
- Tissue Engineering Group Department of Pharmacy Universidad Nacional de Colombia Bogotá Colombia
- Biotechnology Laboratory, Basic Oral Research Unit (UIBO) School of Odontology Universidad El Bosque Bogotá Colombia
| | - Gloria I. Lafaurie
- Biotechnology Laboratory, Basic Oral Research Unit (UIBO) School of Odontology Universidad El Bosque Bogotá Colombia
| | - Marta R. Fontanilla
- Tissue Engineering Group Department of Pharmacy Universidad Nacional de Colombia Bogotá Colombia
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Exposure to Aggregatibacter actinomycetemcomitans before Symptom Onset and the Risk of Evolving to Rheumatoid Arthritis. J Clin Med 2020; 9:jcm9061906. [PMID: 32570853 PMCID: PMC7357066 DOI: 10.3390/jcm9061906] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 12/15/2022] Open
Abstract
Periodontal disease has been implicated in the pathogenesis of rheumatoid arthritis (RA), an autoimmune disease characterized by immune-mediated synovial damage, and antibodies to citrullinated antigens. Here, we investigate the association between exposure to the periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa) and the development of RA. IgM, IgG and IgA antibodies to Aa leukotoxin A (LtxA) were detected by ELISA in plasma from a cohort of Swedish adults at different stages of RA development, from before onset of symptoms to established disease. Patients with early and established RA had increased levels of anti-LtxA IgM compared with matched non-RA controls and periodontally healthy individuals. Logistic regression revealed that anti-LtxA IgM levels were associated with RA during early disease (OR 1.012, 95%CI 1.007, 1.017), which was maintained after adjustment for smoking, anti-CCP antibodies, rheumatoid factor, HLA-DRB1 shared epitope alleles and sex. We found no association between anti-LtxA IgG/IgA antibodies and RA at any stage of disease development. The data support a temporal association between anti-LtxA IgM antibodies and the development of RA, suggesting that a subset of RA patients may have been exposed to Aa around the time of transition from being asymptomatic to become a patient with RA.
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Belibasakis GN, Maula T, Bao K, Lindholm M, Bostanci N, Oscarsson J, Ihalin R, Johansson A. Virulence and Pathogenicity Properties of Aggregatibacter actinomycetemcomitans. Pathogens 2019; 8:E222. [PMID: 31698835 PMCID: PMC6963787 DOI: 10.3390/pathogens8040222] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/29/2019] [Accepted: 11/04/2019] [Indexed: 02/06/2023] Open
Abstract
Aggregatibacter actinomycetemcomitans is a periodontal pathogen colonizing the oral cavity of a large proportion of the human population. It is equipped with several potent virulence factors that can cause cell death and induce or evade inflammation. Because of the large genetic diversity within the species, both harmless and highly virulent genotypes of the bacterium have emerged. The oral condition and age, as well as the geographic origin of the individual, influence the risk to be colonized by a virulent genotype of the bacterium. In the present review, the virulence and pathogenicity properties of A. actinomycetemcomitans will be addressed.
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Affiliation(s)
- Georgios N. Belibasakis
- Division of Oral Diseases, Department of Dental Medicine, Karolinska Institutet, S-141 04 Huddinge, Sweden; (G.N.B.); (K.B.); (N.B.)
| | - Terhi Maula
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; (T.M.); (R.I.)
| | - Kai Bao
- Division of Oral Diseases, Department of Dental Medicine, Karolinska Institutet, S-141 04 Huddinge, Sweden; (G.N.B.); (K.B.); (N.B.)
| | - Mark Lindholm
- Department of Odontology, Umeå University, S-901 87 Umeå, Sweden; (M.L.); (J.O.)
| | - Nagihan Bostanci
- Division of Oral Diseases, Department of Dental Medicine, Karolinska Institutet, S-141 04 Huddinge, Sweden; (G.N.B.); (K.B.); (N.B.)
| | - Jan Oscarsson
- Department of Odontology, Umeå University, S-901 87 Umeå, Sweden; (M.L.); (J.O.)
| | - Riikka Ihalin
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; (T.M.); (R.I.)
| | - Anders Johansson
- Department of Odontology, Umeå University, S-901 87 Umeå, Sweden; (M.L.); (J.O.)
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Oscarsson J, Claesson R, Lindholm M, Höglund Åberg C, Johansson A. Tools of Aggregatibacter actinomycetemcomitans to Evade the Host Response. J Clin Med 2019; 8:E1079. [PMID: 31336649 PMCID: PMC6678183 DOI: 10.3390/jcm8071079] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/08/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023] Open
Abstract
Periodontitis is an infection-induced inflammatory disease that affects the tooth supporting tissues, i.e., bone and connective tissues. The initiation and progression of this disease depend on dysbiotic ecological changes in the oral microbiome, thereby affecting the severity of disease through multiple immune-inflammatory responses. Aggregatibacter actinomycetemcomitans is a facultative anaerobic Gram-negative bacterium associated with such cellular and molecular mechanisms associated with the pathogenesis of periodontitis. In the present review, we outline virulence mechanisms that help the bacterium to escape the host response. These properties include invasiveness, secretion of exotoxins, serum resistance, and release of outer membrane vesicles. Virulence properties of A. actinomycetemcomitans that can contribute to treatment resistance in the infected individuals and upon translocation to the circulation, also induce pathogenic mechanisms associated with several systemic diseases.
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Affiliation(s)
- Jan Oscarsson
- Department of Odontology, Oral Microbiology, Umeå University, S-90187 Umeå, Sweden
| | - Rolf Claesson
- Department of Odontology, Oral Microbiology, Umeå University, S-90187 Umeå, Sweden
| | - Mark Lindholm
- Department of Odontology, Oral Microbiology, Umeå University, S-90187 Umeå, Sweden
| | - Carola Höglund Åberg
- Department of Odontology, Molecular Periodontology, Umeå University, S-901 87 Umeå, Sweden
| | - Anders Johansson
- Department of Odontology, Molecular Periodontology, Umeå University, S-901 87 Umeå, Sweden.
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Pietiäinen M, Liljestrand JM, Kopra E, Pussinen PJ. Mediators between oral dysbiosis and cardiovascular diseases. Eur J Oral Sci 2019; 126 Suppl 1:26-36. [PMID: 30178551 DOI: 10.1111/eos.12423] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2018] [Indexed: 12/11/2022]
Abstract
Clinical periodontitis is associated with an increased risk for cardiovascular diseases (CVDs) through systemic inflammation as the etiopathogenic link. Whether the oral microbiota, especially its quality, quantity, serology, and virulence factors, plays a role in atherogenesis is not clarified. Patients with periodontitis are exposed to bacteria and their products, which have access to the circulation directly through inflamed oral tissues and indirectly (via saliva) through the gastrointestinal tract, resulting in systemic inflammatory and immunologic responses. Periodontitis is associated with persistent endotoxemia, which has been identified as a notable cardiometabolic risk factor. The serology of bacterial biomarkers for oral dysbiosis is associated with an increased risk for subclinical atherosclerosis, prevalent and future coronary artery disease, and incident and recurrent stroke. In addition to species-specific antibodies, the immunologic response includes persistent, cross-reactive, proatherogenic antibodies against host-derived antigens. Periodontitis may affect lipoprotein metabolism at all levels, and all lipoprotein classes are affected. Periodontitis or its bacterial signatures may be involved not only in increased storage of proatherogenic lipids but also in attenuation of the anti-atherogenic processes, thereby putatively increasing the net risk of atherosclerosis. In this review we summarize possible molecular mediators between the dysbiotic oral microbiota and atherosclerotic processes.
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Affiliation(s)
- Milla Pietiäinen
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - John M Liljestrand
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Elisa Kopra
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Pirkko J Pussinen
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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Hirschfeld J, Roberts HM, Chapple ILC, Parčina M, Jepsen S, Johansson A, Claesson R. Effects of Aggregatibacter actinomycetemcomitans leukotoxin on neutrophil migration and extracellular trap formation. J Oral Microbiol 2016; 8:33070. [PMID: 27834173 PMCID: PMC5103672 DOI: 10.3402/jom.v8.33070] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 09/26/2016] [Accepted: 10/04/2016] [Indexed: 12/12/2022] Open
Abstract
Background Aggressive periodontitis is associated with the presence of Aggregatibacter actinomycetemcomitans, a leukotoxin (Ltx)-producing periodontal pathogen. Ltx has the ability to lyse white blood cells including neutrophils. Objectives This study was aimed at investigating the interactions between neutrophils and Ltx with regard to the chemotactic properties of Ltx and the release of neutrophil extracellular traps (NETs). Methods Neutrophils from healthy blood donors were isolated and incubated for 30 min and 3 h with increasing concentrations of Ltx (1, 10, and 100 ng/mL) as well as with A. actinomycetemcomitans strains (NCTC 9710 and HK 1651) producing different levels of Ltx. Formation of NETs and cell lysis were assessed by microscopy, fluorescence-based assays, and measurement of released lactate dehydrogenase. Neutrophil migration in response to different Ltx gradients was monitored by real-time video microscopy, and image analysis was performed using ImageJ software. Results Although Ltx (10 and 100 ng/mL) and the leukotoxic A. actinomycetemcomitans strain HK 1651 lysed some neutrophils, other cells were still capable of performing NETosis in a concentration-dependent manner. Low doses of Ltx and the weakly leukotoxic strain NCTC 9710 did not lead to neutrophil lysis, but did induce some NETosis. Furthermore, all three concentrations of Ltx enhanced random neutrophil movement; however, low directional accuracy was observed compared with the positive control (fMLP). Conclusions The results indicate that Ltx acts both as a neutrophil activator and also causes cell death. In addition, Ltx directly induces NETosis in neutrophils prior to cell lysis. In future studies, the underlying pathways involved in Ltx-meditated neutrophil activation and NETosis need to be investigated further.
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Affiliation(s)
- Josefine Hirschfeld
- Periodontal Research Group, Birmingham Dental School & Hospital, Birmingham, United Kingdom.,Department of Periodontology, Operative and Preventive Dentistry, University Hospital Bonn, Bonn, Germany;
| | - Helen M Roberts
- Periodontal Research Group, Birmingham Dental School & Hospital, Birmingham, United Kingdom
| | - Iain L C Chapple
- Periodontal Research Group, Birmingham Dental School & Hospital, Birmingham, United Kingdom
| | - Marijo Parčina
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Søren Jepsen
- Department of Periodontology, Operative and Preventive Dentistry, University Hospital Bonn, Bonn, Germany
| | - Anders Johansson
- Section Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Rolf Claesson
- Section Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
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