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Szentirmai E, Buckley K, Massie AR, Kapas L. Lipopolysaccharide-Mediated Effects of the Microbiota on Sleep and Body Temperature. RESEARCH SQUARE 2024:rs.3.rs-3995260. [PMID: 38496422 PMCID: PMC10942547 DOI: 10.21203/rs.3.rs-3995260/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Background Recent research suggests that microbial molecules translocated from the intestinal lumen into the host's internal environment may play a role in various physiological functions, including sleep. Previously, we identified that butyrate, a short-chain fatty acid, produced by intestinal bacteria, and lipoteichoic acid, a cell wall component of gram-positive bacteria induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Building upon these findings, we aimed to explore the sleep signaling potential of intraportally administered lipopolysaccharide, a primary component of gram-negative bacterial cell walls, in rats. Results Low dose of lipopolysaccharide (1 μg/kg) increased sleep duration and prolonged fever, without affecting systemic lipopolysaccharide levels. Interestingly, administering LPS systemically outside the portal region at a dose 20 times higher did not affect sleep, indicating a localized sensitivity within the hepatoportal region, encompassing the portal vein and liver, for the sleep and febrile effects of lipopolysaccharide. Furthermore, both the sleep- and fever-inducing effects of LPS were inhibited by indomethacin, a prostaglandin synthesis inhibitor, and replicated by intraportal administration of prostaglandin E2 or arachidonic acid, suggesting the involvement of the prostaglandin system in mediating these actions. Conclusions These findings underscore the dynamic influence of lipopolysaccharide in the hepatoportal region on sleep and fever mechanisms, contributing to a complex microbial molecular assembly that orchestrates communication between the intestinal microbiota and brain. Lipopolysaccharide is a physiological component of plasma in both the portal and extra-portal circulation, with its levels rising in response to everyday challenges like high-fat meals, moderate alcohol intake, sleep loss and psychological stress. The increased translocation of lipopolysaccharide under such conditions may account for their physiological impact in daily life, highlighting the intricate interplay between microbial molecules and host physiology.
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2
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Rajcic D, Kromm F, Hernández-Arriaga A, Brandt A, Baumann A, Staltner R, Camarinha-Silva A, Bergheim I. Supplementing L-Citrulline Can Extend Lifespan in C. elegans and Attenuate the Development of Aging-Related Impairments of Glucose Tolerance and Intestinal Barrier in Mice. Biomolecules 2023; 13:1579. [PMID: 38002262 PMCID: PMC10669166 DOI: 10.3390/biom13111579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/19/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
L-Citrulline (L-Cit) is discussed to possess a protective effect on intestinal barrier dysfunction but also to diminish aging-associated degenerative processes. Here, the effects of L-Cit on lifespan were assessed in C. elegans, while the effects of L-Cit on aging-associated decline were determined in C57BL/6J mice. For lifespan analysis, C. elegans were treated with ±5 mM L-Cit. Twelve-month-old male C57BL/6J mice (n = 8-10/group) fed a standard chow diet received drinking water ± 2.5 g/kg/d L-Cit or 5 g/kg/d hydrolyzed soy protein (Iso-N-control) for 16 or 32 weeks. Additionally, 4-month-old C57BL/6J mice were treated accordingly for 8 weeks. Markers of senescence, glucose tolerance, intestinal barrier function, and intestinal microbiota composition were analyzed in mice. L-Cit treatment significantly extended the lifespan of C. elegans. The significant increase in markers of senescence and signs of impaired glucose tolerance found in 16- and 20-month-old control mice was attenuated in L-Cit-fed mice, which was associated with protection from intestinal barrier dysfunction and a decrease in NO2- levels in the small intestine, while no marked differences in intestinal microbiota composition were found when comparing age-matched groups. Our results suggest that pharmacological doses of L-Cit may have beneficial effects on lifespan in C. elegans and aging-associated decline in mice.
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Affiliation(s)
- Dragana Rajcic
- Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, 1090 Vienna, Austria
| | - Franziska Kromm
- Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, 1090 Vienna, Austria
| | | | - Annette Brandt
- Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, 1090 Vienna, Austria
| | - Anja Baumann
- Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, 1090 Vienna, Austria
| | - Raphaela Staltner
- Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, 1090 Vienna, Austria
| | - Amélia Camarinha-Silva
- Institute of Animal Science, University of Hohenheim, 70593 Stuttgart, Germany (A.C.-S.)
| | - Ina Bergheim
- Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, 1090 Vienna, Austria
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3
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Yi Z, Geng S, Li L. Comparative analyses of monocyte memory dynamics from mice to humans. Inflamm Res 2023; 72:1539-1549. [PMID: 37453943 PMCID: PMC10499745 DOI: 10.1007/s00011-023-01762-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/13/2023] [Accepted: 06/23/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND Innate monocytes can adopt dynamic "memory" states ranging from low-grade inflammation to pathogenic exhaustion, dependent upon signal strength and history of challenges. Low-grade inflammatory monocytes facilitate the pathogenesis of chronic inflammatory diseases, while exhausted monocytes drive the pathogenesis of severe sepsis. Although clinical and basic studies suggest the conservation of key features of exhausted monocytes from human and murine sepsis, systems analyses of monocyte exhaustion among human and murine monocytes are lacking. METHODS We performed cross examination of septic monocytes scRNAseq data recently collected from human sepsis patients as well as experimental septic mice, in reference to monocytes experimentally exhausted in vitro. Furthermore, we performed pseudo-time analyses of in vitro programmed monocytes following prolonged challenges causing either low-grade inflammation or exhaustion. Additional comparative analyses of low-grade inflammatory monocytes were performed with scRNAseq data from selected human patients with chronic low-grade inflammatory diseases. RESULTS Our systems analyses reveal key features of monocyte exhaustion including reduced differentiation, pathogenic inflammation and immune suppression that are highly conserved in human and murine septic monocytes, and captured by in vitro experimental exhaustion. Pseudo-time analyses reveal that monocytes initially transition into a less-differentiated state with proliferative potential. The expansion of proliferative monocytes can be observed not only in experimentally challenged monocytes, but also in tissues of murine sepsis and human septic blood. We observed that monocytes similarly transition into the less-differentiated state when challenged with a subclinical dose endotoxin under chronic inflammatory conditions. Instead of being exhausted, monocytes with prolonged challenges with super-low dose endotoxin bifurcate into the low-grade inflammatory immune-enhancing or the chemotactic/adhesive state, often see in atherosclerosis or auto-immune diseases. CONCLUSIONS Key features of monocyte memory dynamics are identified and conserved in human and murine monocytes, which can be captured by prolonged challenges of innate signals with varying signal strength.
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Affiliation(s)
- Ziyue Yi
- Department of Biological Sciences, Virginia Tech, 149 Life Science 1 Bldg, Blacksburg, VA, 24061-0910, USA
| | - Shuo Geng
- Department of Biological Sciences, Virginia Tech, 149 Life Science 1 Bldg, Blacksburg, VA, 24061-0910, USA
| | - Liwu Li
- Department of Biological Sciences, Virginia Tech, 149 Life Science 1 Bldg, Blacksburg, VA, 24061-0910, USA.
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4
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Kim DB, Unenkhuu B, Kim GJ, Kim SW, Kim HS. Cynarin attenuates LPS-induced endothelial inflammation via upregulation of the negative regulator MKP-3. Anim Cells Syst (Seoul) 2022; 26:119-128. [PMID: 35784390 PMCID: PMC9246029 DOI: 10.1080/19768354.2022.2077438] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Clinical observations have revealed that non-resolving low-grade inflammation is linked to the pathogenesis of chronic inflammatory diseases, for example arthritis, atherosclerosis, Alzheimer’s disease, diabetes, and chronic kidney disease. Interestingly, low levels of circulating lipopolysaccharides (LPS) derived from the outer membrane of gram-negative bacteria appear to be one of the primary causes of persistent low-grade inflammation. The inner surface of the blood vessels is lined with endothelial cells; therefore, even low levels of circulating LPS can directly activate these cells and elicit specific cellular responses, such as an increase in the expression levels of cell adhesion molecules and proinflammatory mediators. In endothelial cells, LPS exposure results in an inflammatory response through activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases. Cynarin, a phytochemical found in artichokes, has several pharmacological properties against endothelial inflammation. In the present study, we discovered that cynarin suppressed the LPS-induced increase in the expression levels of vascular cell adhesion molecule-1 and proinflammatory mediators such as monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), and interleukin-1β in EA.hy926 cells. Further, cynarin inhibited the activation of p38 and NF-κB pathways by inducing the negative regulator mitogen-activated protein kinase phosphatase 3 (MKP-3) in LPS-stimulated EA.hy926 cells. In conclusion, cynarin alleviates inflammation by upregulating MKP-3, a negative regulator of p38 and NF-κB, and it may be a therapeutic option for treating endothelial inflammation-related diseases.
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Affiliation(s)
- Da Bin Kim
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon, Republic of Korea
- Program in Biomedical Science and Engineering, College of Medicine, Inha University, Incheon, Republic of Korea
| | - Banzragchgarav Unenkhuu
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon, Republic of Korea
| | - Grace Jisoo Kim
- Yongsan International School of Seoul, Seoul, Republic of Korea
| | - Seung-Woo Kim
- Department of Biomedical Sciences, College of Medicine, Inha University, Incheon, Republic of Korea
| | - Hong Seok Kim
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon, Republic of Korea
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5
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Pussinen PJ, Kopra E, Pietiäinen M, Lehto M, Zaric S, Paju S, Salminen A. Periodontitis and cardiometabolic disorders: The role of lipopolysaccharide and endotoxemia. Periodontol 2000 2022; 89:19-40. [PMID: 35244966 PMCID: PMC9314839 DOI: 10.1111/prd.12433] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lipopolysaccharide is a virulence factor of gram-negative bacteria with a crucial importance to the bacterial surface integrity. From the host's perspective, lipopolysaccharide plays a role in both local and systemic inflammation, activates both innate and adaptive immunity, and can trigger inflammation either directly (as a microbe-associated molecular pattern) or indirectly (by inducing the generation of nonmicrobial, danger-associated molecular patterns). Translocation of lipopolysaccharide into the circulation causes endotoxemia, which is typically measured as the biological activity of lipopolysaccharide to induce coagulation of an aqueous extract of blood cells of the assay. Apparently healthy subjects have a low circulating lipopolysaccharide activity, since it is neutralized and cleared rapidly. However, chronic endotoxemia is involved in the pathogenesis of many inflammation-driven conditions, especially cardiometabolic disorders. These include atherosclerotic cardiovascular diseases, obesity, liver diseases, diabetes, and metabolic syndrome, where endotoxemia has been recognized as a risk factor. The main source of endotoxemia is thought to be the gut microbiota. However, the oral dysbiosis in periodontitis, which is typically enriched with gram-negative bacterial species, may also contribute to endotoxemia. As endotoxemia is associated with an increased risk of cardiometabolic disorders, lipopolysaccharide could be considered as a molecular link between periodontal microbiota and cardiometabolic diseases.
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Affiliation(s)
- Pirkko J Pussinen
- 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
| | - Milla Pietiäinen
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Markku Lehto
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland.,Abdominal Center, Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Clinical and Molecular Metabolism, Faculty of Medicine Research Programs, University of Helsinki, Helsinki, Finland
| | - Svetislav Zaric
- Faculty of Dentistry, Oral & Craniofacial Sciences, Kings College London, London, UK
| | - Susanna Paju
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Aino Salminen
- Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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6
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Alshareef GH, Mohammed AE, Abumaree M, Basmaeil YS. Phenotypic and Functional Responses of Human Decidua Basalis Mesenchymal Stem/Stromal Cells to Lipopolysaccharide of Gram-Negative Bacteria. STEM CELLS AND CLONING-ADVANCES AND APPLICATIONS 2021; 14:51-69. [PMID: 34754198 PMCID: PMC8572118 DOI: 10.2147/sccaa.s332952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 10/11/2021] [Indexed: 12/24/2022]
Abstract
Introduction Human decidua basalis mesenchymal stem cells (DBMSCs) are potential therapeutics for the medication to cure inflammatory diseases, like atherosclerosis. The current study investigates the capacity of DBMSCs to stay alive and function in a harmful inflammatory environment induced by high levels of lipopolysaccharide (LPS). Methods DBMSCs were exposed to different levels of LPS, and their viability and functional responses (proliferation, adhesion, and migration) were examined. Furthermore, DBMSCs’ expression of 84 genes associated with their functional activities in the presence of LPS was investigated. Results Results indicated that LPS had no significant effect on DBMSCs’ adhesion, migration, and proliferation (24 h and 72 h) (p > 0.05). However, DBMSCs’ proliferation was significantly reduced at 10 µg/mL of LPS at 48 h (p < 0.05). In addition, inflammatory cytokines and receptors related to adhesion, proliferation, migration, and differentiation were significantly overexpressed when DBMSCs were treated with 10 µg/mL of LPS (p < 0.05). Conclusion These results indicated that DBMSCs maintained their functional activities (proliferation, adhesion, and migration) in the presence of LPS as there was no variation between the treated DBMSCs and the control group. This study will lay the foundation for future preclinical and clinical studies to confirm the appropriateness of DBMSCs as a potential medication to cure inflammatory diseases, like atherosclerosis.
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Affiliation(s)
- Ghofran Hasan Alshareef
- Biology Department, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, 84428, Saudi Arabia
| | - Afrah E Mohammed
- Biology Department, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, 84428, Saudi Arabia
| | - Mohammed Abumaree
- Stem Cell & Regenerative Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia.,College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, 11481, Saudi Arabia
| | - Yasser S Basmaeil
- Stem Cell & Regenerative Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
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7
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Du H, Rao Y, Liu R, Deng K, Guan Y, Luo D, Mao Q, Yu J, Bo T, Fan Z, Ouyang H, Feng Y, Zhu W. Proteomics and metabolomics analyses reveal the full spectrum of inflammatory and lipid metabolic abnormalities in dyslipidemia. Biomed Chromatogr 2021; 35:e5183. [PMID: 34058018 DOI: 10.1002/bmc.5183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/18/2021] [Accepted: 05/26/2021] [Indexed: 01/21/2023]
Abstract
Dyslipidemia is a common, chronic metabolic disease associated with cardiovascular complications. Due to the multiplicity of etiological factors, the pathogenesis of dyslipidemia is still unclear. In this study, we combined proteomics and metabolomics methods to analyze the plasma of patients with dyslipidemia and healthy subjects. isobaric tags for relative and absolute quantification (iTRAQ) markers, combined with LC-MS/MS proteomics technology and the UHPLC/Orbitfast-X Tribrid system, were used to establish the metabolite profile in clinical dyslipidemia. A total of 137 differentially expressed proteins, mainly related to biological processes such as protein activation cascades, adaptive immune responses, complement activation, acute inflammatory responses, and regulation of acute inflammatory responses, were identified. These proteins are involved in the regulation of important metabolic pathways, such as immunity and inflammation, coagulation and hemostasis, lipid metabolism, and oxidation and antioxidant defenses. The analysis of clinical metabolites showed there were 69 different metabolites in plasma, mainly related to glycerolipid, sphingolipid, porphyrin, α-linolenic acid, linoleic acid, and arachidonic acid metabolism, suggesting that the regulation of inflammation and lipid metabolism may be disturbed in patients with dyslipidemia. Among these, significant changes were observed in indole-3-propionic acid (IPA), which is considered as a potential biomarker of dyslipidemia. The combined analysis of proteins and metabolites showed that arachidonic acid, linoleic acid, and lipid metabolic pathways were closely related to dyslipidemia. IPA may be a potential biomarker. The information provided in this study may provide new insights into the pathogenesis of animal models of dyslipidemia and related disease models, as well as potential intervention targets.
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Affiliation(s)
- Hui Du
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Yifei Rao
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Ronghua Liu
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Kesui Deng
- The Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Yongmei Guan
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Dewei Luo
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Qiping Mao
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Jianwei Yu
- The Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Tao Bo
- Thermo Fisher Scientific-CN, Shanghai, China
| | - Ziquan Fan
- Thermo Fisher Scientific-CN, Shanghai, China
| | - Hui Ouyang
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Yulin Feng
- State Key Laboratory of Innovative Drug and Efficient Energy-Saving Pharmaceutical Equipment, Nanchang, China
| | - Weifeng Zhu
- Key Laboratory of Ministry of Education of Jiangxi University of Traditional Chinese Medicine, Nanchang, China
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8
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Zhang Y, Lin R, Pradhan K, Geng S, Li L. Innate Priming of Neutrophils Potentiates Systemic Multiorgan Injury. Immunohorizons 2020; 4:392-401. [PMID: 32631901 PMCID: PMC7445012 DOI: 10.4049/immunohorizons.2000039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 06/14/2020] [Indexed: 11/19/2022] Open
Abstract
Excessive inflammatory reactions mediated by first-responder cells such as neutrophils contribute to the severity of multiorgan failure associated with systemic injury and infection. Systemic subclinical endotoxemia due to mucosal leakage may aggravate neutrophil activation and tissue injury. However, mechanisms responsible for neutrophil inflammatory polarization are not well understood. In this study, we demonstrate that subclinical low-dose endotoxemia can potently polarize neutrophils into an inflammatory state in vivo and in vitro, as reflected in elevated expression of adhesion molecules such as ICAM-1 and CD29, and reduced expression of suppressor molecule CD244. When subjected to a controlled administration of gut-damaging chemical dextran sulfate sodium, mice conditioned with subclinical dose LPS exhibit significantly elevated infiltration of neutrophils into organs such as liver, colon, and spleen, associated with severe multiorgan damage as measured by biochemical as well as histological assays. Subclinical dose LPS is sufficient to induce potent activation of SRC kinase as well as downstream activation of STAT1/STAT5 in neutrophils, contributing to the inflammatory neutrophil polarization. We also demonstrate that the administration of 4-phenylbutyric acid, an agent known to relieve cell stress and enhance peroxisome function, can reduce the activation of SRC kinase and enhance the expression of suppressor molecule CD244 in neutrophils. We show that i.v. injection of 4-phenylbutyric acid conditioned neutrophils can effectively reduce the severity of multiorgan damage in mice challenged with dextran sulfate sodium. Collectively, our data, to our knowledge, reveal novel inflammatory polarization of neutrophils by subclinical endotoxemia conducive for aggravated multiorgan damage as well as potential therapeutic intervention.
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Affiliation(s)
- Yao Zhang
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061; and
| | - RuiCi Lin
- Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, VA 24061
| | - Kisha Pradhan
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061; and
| | - Shuo Geng
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061; and
| | - Liwu Li
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061; and
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9
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Jin CJ, Baumann A, Brandt A, Engstler AJ, Nier A, Hege M, Schmeer C, Kehm R, Höhn A, Grune T, Witte OW, Bergheim I. Aging-related liver degeneration is associated with increased bacterial endotoxin and lipopolysaccharide binding protein levels. Am J Physiol Gastrointest Liver Physiol 2020; 318:G736-G747. [PMID: 32090603 DOI: 10.1152/ajpgi.00345.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Aging is a risk factor in the development of many diseases, including liver-related diseases. The two aims of the present study were 1) to determine how aging affects liver health in mice in the absence of any interventions and 2) if degenerations observed in relation to blood endotoxin levels are critical in aging-associated liver degeneration. Endotoxin levels and markers of liver damage, mitochondrial dysfunction, insulin resistance, and apoptosis as well as the Toll-like receptor 4 (Tlr-4) signaling cascade were studied in liver tissue and blood, respectively, of 3- and 24-mo-old male C57BL/6J mice. In a second set of experiments, 3- to 4-mo-old and 14-mo-old female lipopolysaccharide-binding protein (LBP)-/- mice and littermates fed standard chow, markers of liver damage, insulin resistance, and mitochondrial dysfunction were assessed. Plasma activity of aspartate aminotransferase and histological signs of hepatic inflammation and fibrosis were significantly higher in old C57BL/6J mice than in young animals. The number of neutrophils, CD8α-positive cells, and mRNA expression of markers of apoptosis were also significantly higher in livers of old C57BL/6J mice compared with young animals, being also associated with a significant induction of hepatic Tlr-4 and LBP expression as well as higher endotoxin levels in peripheral blood. Compared with age-matched littermates, LBP-/- mice display less signs of senescence in liver. Taken together, our data suggest that, despite being fed standard chow, old mice developed liver inflammation and beginning fibrosis and that bacterial endotoxin may play a critical role herein.NEW & NOTEWORTHY Old age in mice is associated with marked signs of liver degeneration, hepatic inflammation, and fibrosis. Aging-associated liver degeneration is associated with elevated bacterial endotoxin levels and an induction of lipopolysaccharide-binding protein (LBP) and Toll-like receptor 4-dependent signaling cascades in liver tissue. Furthermore, in old aged LBP-/- mice, markers of senescence seem to be lessened, supporting the hypothesis that bacterial endotoxin levels might be critical in aging-associated decline of liver.
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Affiliation(s)
- Cheng Jun Jin
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany.,Clinic for Gastroenterology, Hepatology, and Infectiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Anja Baumann
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany.,Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, Vienna, Austria
| | - Annette Brandt
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany.,Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, Vienna, Austria
| | - Anna Janina Engstler
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany.,Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, Vienna, Austria
| | - Anika Nier
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany.,Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, Vienna, Austria
| | - Marianne Hege
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany
| | - Christian Schmeer
- Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany
| | - Richard Kehm
- German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
| | - Annika Höhn
- German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
| | - Tilman Grune
- German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany.,German Center for Diabetes Research, Munich-Neuherberg, Germany
| | - Otto W Witte
- Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany
| | - Ina Bergheim
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany.,Department of Nutritional Sciences, Molecular Nutritional Science, University of Vienna, Vienna, Austria
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10
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Zhang C, Tian F, Zhang M, Zhang Z, Bai M, Guo G, Zheng W, Wang Q, Shi Y, Wang L. Endotoxin contamination, a potentially important inflammation factor in water and wastewater: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 681:365-378. [PMID: 31108357 DOI: 10.1016/j.scitotenv.2019.05.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/28/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
Endotoxins, also referred to as lipopolysaccharides or pyrogens, are major components embedded in the outer cell wall membrane of most Gram-negative bacteria and some cyanobacteria. As common pyrogens and strong immune stimulators, health hazards associated with endotoxins in water and wastewater have been attracting attention in recent years. In this paper, the characteristics, existing forms, and detection assays of endotoxins in water and wastewater are reviewed. Cellular response and pathophysiological effects, and main exposure tracts of endotoxins in water and wastewater are discussed. Levels of endotoxin contamination in water, wastewater, and their aerosols are presented. The removal effects of different water and wastewater treatment processes are summarized. Hence, it is important to: (i) Improve investigations into endotoxin contamination in water and wastewater in order to identify their source, occurrence, and fate. (ii) Implement water and wastewater treatment processes capable of ensuring low levels of endotoxins. This review aims to identify efficient water and wastewater treatment processes capable of ensuring the production of WTPs and WWTPs effluents with a low level of endotoxin activity, and to guarantee the reduction of endotoxin exposure risks to the consumers of water and wastewater.
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Affiliation(s)
- Can Zhang
- Center for Disease Control and Prevention of Chinese PLA, Beijing 100071, China.
| | - Fang Tian
- School of Environmental Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Minglu Zhang
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing 100048, China
| | - Zhiqing Zhang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin 300050, China
| | - Miao Bai
- Center for Disease Control and Prevention of Chinese PLA, Beijing 100071, China
| | - Guang Guo
- School of Environmental Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Wenjie Zheng
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Normal University, Tianjin, 300387, China
| | - Qiang Wang
- Center for Disease Control and Prevention of Chinese PLA, Beijing 100071, China
| | - Yun Shi
- Center for Disease Control and Prevention of Chinese PLA, Beijing 100071, China
| | - Lili Wang
- Center for Disease Control and Prevention of Chinese PLA, Beijing 100071, China
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11
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Geng S, Zhang Y, Lee C, Li L. Novel reprogramming of neutrophils modulates inflammation resolution during atherosclerosis. SCIENCE ADVANCES 2019; 5:eaav2309. [PMID: 30775441 PMCID: PMC6365109 DOI: 10.1126/sciadv.aav2309] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/21/2018] [Indexed: 05/04/2023]
Abstract
Nonresolving inflammation perpetuated by innate leukocytes is involved in the pathogenesis of unstable atherosclerosis. However, the role and regulation of neutrophils related to nonresolving inflammation and atherosclerosis are poorly understood. We report herein that chronic subclinical endotoxemia, a risk factor for atherosclerosis, skewed neutrophils into a nonresolving inflammatory state with elevated levels of inflammatory mediators (Dectin-1, MMP9, and LTB4) and reduced levels of homeostatic mediators (LRRC32, TGFβ, and FPN). The polarization of neutrophils was due to ROS-mediated activation of oxCAMKII, caused by altered peroxisome homeostasis and reduced lysosome fusion. Application of 4-phenylbutyrate (4-PBA) enhanced peroxisome homeostasis of neutrophils, reduced oxCAMKII, and rebalanced the expression profiles of pro- and anti-inflammatory mediators. Adoptive transfer of neutrophils programmed by subclinical endotoxemia rendered exacerbated atherosclerosis. In contrast, transfer of ex vivo programmed neutrophils by 4-PBA reduced the pathogenesis of atherosclerosis. Our data define novel neutrophil dynamics associated with the progression and regression of atherosclerosis.
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12
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Szeto CC, McIntyre CW, Li PKT. Circulating Bacterial Fragments as Cardiovascular Risk Factors in CKD. J Am Soc Nephrol 2018; 29:1601-1608. [PMID: 29666156 PMCID: PMC6054355 DOI: 10.1681/asn.2018010068] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cardiovascular disease (CVD) is a major cause of mortality and morbidity in patients with CKD. In the past decade, intestinal dysbiosis and altered gut epithelial barrier function are increasingly recognized in CKD. Uremic patients have slow intestinal transit time, impaired protein assimilation, and decreased consumption of dietary fiber. The use of multiple medications also may contribute to the proliferation of dysbiotic bacteria, which affect the barrier function of intestinal epithelium. In addition, fluid overload and uremic toxins per se directly reduce the gut barrier function. The major consequence of these alterations, the translocation of bacterial fragments from bowel lumen to systemic circulation, can lead to diverse biologic effects and probably represents an important nontraditional CVD risk factor in CKD. Among all bacterial fragments, endotoxin is the most well studied. Plasma endotoxin levels are markedly elevated in both patients with CKD and those on dialysis, and are associated with the systemic inflammatory state, accelerated atherosclerosis, and clinical CVD in patients on dialysis. Optimization of BP control and the use of ultrapure dialysate can reduce plasma endotoxin levels, with probable metabolic and cardiovascular benefits. The benefit of synbiotic therapy is not confirmed, although results from animal studies are impressive. The biologic effects and clinical relevance of other bacterial fragments, such as bacterial DNA fragments, are less well defined. Further studies are needed to delineate the pathogenic relation between circulating bacterial fragments and CVD, and to define the role of the plasma bacterial fragment level as a prognostic indicator of CKD.
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Affiliation(s)
- Cheuk-Chun Szeto
- Carol and Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Sha Tin, Hong Kong, China; and
| | - Christopher William McIntyre
- Division of Nephrology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Philip Kam-Tao Li
- Carol and Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Sha Tin, Hong Kong, China; and
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13
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Cox MC, Kuliasha AS, Li L, Verbridge SS. 3D Microtissue Models to Analyze the Effects of Ultralow Dose LPS on Vascular Sprouting Dynamics in the Tumor Microenvironment. ACS Biomater Sci Eng 2018; 4:357-367. [PMID: 33418730 DOI: 10.1021/acsbiomaterials.6b00800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipopolysaccharide (LPS) plays a major role in innate immune responses and has been shown to impact vascular dynamics when present at high concentrations. However, the impact of ultralow levels of LPS (<100 pg/mL), present in the body during states of chronic inflammation, on vascular dynamics is unclear. In this study, we have integrated a 3D collagen hydrogel tissue mimic with advanced imaging and cell characterization assays to assess the potential impact of chronic inflammation on vascular dynamics, and uncover any alterations in the vascular response to low vs high dose LPS in the context of tumor progression. Accounting for both frequency of sprouting and invasiveness of the sprouts, the treatments of ultralow dose LPS with vascular endothelial growth factor (VEGF), a potent angiogenic promoter and present in excess in the tumor microenvironment, produced enhanced vascular development of human brain microvascular endothelial cells (HBMECs) in our in vitro model. There was no evidence of altered proliferation or apoptosis among the various VEGF treatment groups, indicating an enhanced migratory endothelial cell phenotype results from exposure to ultralow dose LPS with VEGF. The lack of enhanced vascular development upon treatments of high doses of LPS in the presence of VEGF could be partially attributed to an LPS dose-dependent increase in the activation of NF-κB. This study provides insight into the dynamic regulation of vascular development by varying levels of LPS and the potential role of chronic inflammation to prime a pro-angiogenic microenvironment and contribute to tumor progression.
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Affiliation(s)
- Megan C Cox
- Department of Biomedical Engineering and Mechanics, ‡Department of Biological Systems Engineering, and §Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Andrea S Kuliasha
- Department of Biomedical Engineering and Mechanics, Department of Biological Systems Engineering, and §Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Liwu Li
- Department of Biomedical Engineering and Mechanics, Department of Biological Systems Engineering, and Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Scott S Verbridge
- Department of Biomedical Engineering and Mechanics, Department of Biological Systems Engineering, and Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
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14
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Kowalski EJA, Li L. Toll-Interacting Protein in Resolving and Non-Resolving Inflammation. Front Immunol 2017; 8:511. [PMID: 28529512 PMCID: PMC5418219 DOI: 10.3389/fimmu.2017.00511] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 04/18/2017] [Indexed: 12/17/2022] Open
Abstract
Innate leukocytes manifest dynamic and distinct inflammatory responses upon challenges with rising dosages of pathogen-associated molecular pattern molecules such as lipopolysaccharide (LPS). To differentiate signal strengths, innate leukocytes may utilize distinct intracellular signaling circuitries modulated by adaptor molecules. Toll-interacting protein (Tollip) is one of the critical adaptor molecules potentially playing key roles in modulating the dynamic adaptation of innate leukocytes to varying dosages of external stimulants. While Tollip may serve as a negative regulator of nuclear factor κ of activated B cells signaling pathway in cells challenged with higher dosages of LPS, it acts as a positive regulator for low-grade chronic inflammation in leukocytes programmed by subclinical low-dosages of LPS. This review aims to discuss recent progress in our understanding of complex innate leukocyte dynamics and its relevance in the pathogenesis of resolving versus non-resolving chronic inflammatory diseases.
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Affiliation(s)
- Elizabeth J A Kowalski
- Department of Biological Sciences, Virginia Polytechnic State University, Blacksburg, VA, USA
| | - Liwu Li
- Department of Biological Sciences, Virginia Polytechnic State University, Blacksburg, VA, USA
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15
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Host defenses against metabolic endotoxaemia and their impact on lipopolysaccharide detection. Int Rev Immunol 2017; 36:125-144. [DOI: 10.1080/08830185.2017.1280483] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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16
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Liu G, Deng J, Zhang Q, Song W, Chen S, Lou X, Zhang P, Pan K. Porphyromonas gingivalisLipopolysaccharide Stimulation of Vascular Smooth Muscle Cells Activates Proliferation and Calcification. J Periodontol 2016; 87:828-36. [DOI: 10.1902/jop.2016.150602] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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17
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Daulatzai MA. Fundamental role of pan-inflammation and oxidative-nitrosative pathways in neuropathogenesis of Alzheimer's disease in focal cerebral ischemic rats. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2016; 5:102-30. [PMID: 27335702 PMCID: PMC4913220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 02/09/2016] [Indexed: 06/06/2023]
Abstract
Alzheimer's disease (AD) is a chronic progressive neurodegenerative condition of the brain, and it is the most common cause of dementia. Several neurobiological etiologies of AD are described in the literature. These include vascular, infectious, toxic, nutritional, metabolic, and inflammatory. However, these heterogeneous etiologies have a common denominator - viz. Inflammation and oxidative stress. Lipopolysaccharide (LPS) elevates the synthesis of proinflammatory cytokines and chemokines; chronically, together they trigger various pathological responses in the periphery and the CNS including dysfunctional memory consolidation and memory decline. Aging - the main risk factor for AD is inherently associated with inflammation. There are several age-related comorbidities that are also associated with inflammation and oxidative stress. Such co-prevailing aggravating factors, therefore, persist against a background of underlying aging-related pathology. They may converge, and their synergistic propagation may modify the disease course. A critical balance exists between homeostasis/repair and inflammatory factors; chronic, unrelenting inflammatory milieu succeeds in promoting a neuroinflammatory and neurodegenerative outcome. Extensive evidence is available that CNS inflammation is associated with neurodegeneration. LPS, proinflammatory cytokines, several mediators secreted by microglia, and oxidative-nitrosative stress in concert play a pivotal role in triggering neuroinflammatory processes and neurodegeneration. The persistent uncontrolled activity of the above factors can potentiate cognitive decline in tandem enhancing vulnerability to AD. Despite significant progress during the past twenty years, the prevention and treatment of AD have been tantalizingly elusive. Current studies strongly suggest that amelioration/prevention of the deleterious effects of inflammation may prove beneficial in preventing AD onset and retarding cognitive dysfunction in aging and AD. A concerted multi-focal therapeutic effort around the inflammation-oxidative-nitrosative stress paradigm may be crucial in preventing and treating AD. This paper informs on such relevant polypharmacy approach.
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Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE/Melbourne School of Engineering, The University of Melbourne Parkville, Victoria 3010, Australia
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18
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Angelovich TA, Shi MDY, Zhou J, Maisa A, Hearps AC, Jaworowski A. Ex vivo foam cell formation is enhanced in monocytes from older individuals by both extrinsic and intrinsic mechanisms. Exp Gerontol 2016; 80:17-26. [PMID: 27073169 DOI: 10.1016/j.exger.2016.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 02/24/2016] [Accepted: 04/06/2016] [Indexed: 12/20/2022]
Abstract
Aging is the strongest predictor of cardiovascular diseases such as atherosclerosis, which are the leading causes of morbidity and mortality in elderly men. Monocytes play an important role in atherosclerosis by differentiating into foam cells (lipid-laden macrophages) and producing atherogenic proinflammatory cytokines. Monocytes from the elderly have an inflammatory phenotype that may promote atherosclerotic plaque development; here we examined whether they are more atherogenic than those from younger individuals. Using an in vitro model of monocyte transmigration and foam cell formation, monocytes from older men (median age [range]: 75 [58-85] years, n=20) formed foam cells more readily than those of younger men (32 [23-46] years, n=20) (P<0.003) following transmigration across a TNF-activated endothelial monolayer. Compared to young men, monocytes from the elderly had impaired cholesterol efflux and lower expression of regulators of cholesterol transport and metabolism. Foam cell formation was enhanced by soluble factors in serum from older men, but did not correlate with plasma lipid levels. Of the three subsets, intermediate monocytes formed the most foam cells. Therefore, both cellular changes to monocytes and soluble plasma factors in older men primes monocytes for foam cell formation following transendothelial migration, which may contribute to enhanced atherosclerosis in this population.
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Affiliation(s)
- Thomas A Angelovich
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia; School of Applied Sciences, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia
| | - Margaret D Y Shi
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Jingling Zhou
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Anna Maisa
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Anna C Hearps
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Infectious Diseases, Monash University, Level 2 85 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Anthony Jaworowski
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Infectious Diseases, Monash University, Level 2 85 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Immunology, Monash University, Level 6 89 Commercial Road, Melbourne, Victoria 3004, Australia.
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19
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Daulatzai MA. Fundamental role of pan-inflammation and oxidative-nitrosative pathways in neuropathogenesis of Alzheimer's disease. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2016; 5:1-28. [PMID: 27073740 PMCID: PMC4788729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/09/2016] [Indexed: 06/05/2023]
Abstract
Alzheimer's disease (AD) is a chronic progressive neurodegenerative condition of the brain, and it is the most common cause of dementia. Several neurobiological etiologies of AD are described in the literature. These include vascular, infectious, toxic, nutritional, metabolic, and inflammatory. However, these heterogeneous etiologies have a common denominator - viz. Inflammation and oxidative stress. Lipopolysaccharide (LPS) elevates the synthesis of proinflammatory cytokines and chemokines; chronically, together they trigger various pathological responses in the periphery and the CNS including dysfunctional memory consolidation and memory decline. Aging - the main risk factor for AD is inherently associated with inflammation. There are several age-related comorbidities that are also associated with inflammation and oxidative stress. Such co-prevailing aggravating factors, therefore, persist against a background of underlying aging-related pathology. They may converge, and their synergistic propagation may modify the disease course. A critical balance exists between homeostasis/repair and inflammatory factors; chronic, unrelenting inflammatory milieu succeeds in promoting a neuroinflammatory and neurodegenerative outcome. Extensive evidence is available that CNS inflammation is associated with neurodegeneration. LPS, proinflammatory cytokines, several mediators secreted by microglia, and oxidative-nitrosative stress in concert play a pivotal role in triggering neuroinflammatory processes and neurodegeneration. The persistent uncontrolled activity of the above factors can potentiate cognitive decline in tandem enhancing vulnerability to AD. Despite significant progress during the past twenty years, the prevention and treatment of AD have been tantalizingly elusive. Current studies strongly suggest that amelioration/prevention of the deleterious effects of inflammation may prove beneficial in preventing AD onset and retarding cognitive dysfunction in aging and AD. A concerted multi-focal therapeutic effort around the inflammation-oxidative-nitrosative stress paradigm may be crucial in preventing and treating AD. This paper informs on such relevant polypharmacy approach.
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Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE/Melbourne School of Engineering, The University of Melbourne Parkville, Victoria 3010, Australia
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20
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Guo H, Diao N, Yuan R, Chen K, Geng S, Li M, Li L. Subclinical-Dose Endotoxin Sustains Low-Grade Inflammation and Exacerbates Steatohepatitis in High-Fat Diet-Fed Mice. THE JOURNAL OF IMMUNOLOGY 2016; 196:2300-2308. [PMID: 26810228 DOI: 10.4049/jimmunol.1500130] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 12/26/2015] [Indexed: 12/13/2022]
Abstract
Subclinical circulating bacterial endotoxin LPS has been implicated as an important cofactor in the development and progression of nonalcoholic steatohepatitis, but the underlying mechanisms remain unclear. In this study, we demonstrated that 4-wk injection with superlow-dose LPS significantly promoted neutrophil infiltration and accelerated nonalcoholic steatohepatitis progression, including exacerbated macrovesicular steatosis, inflammation, and hepatocyte ballooning in high-fat diet-fed apolipoprotein E knockout mice. This effect could sustain for a month after stoppage of LPS injection. LPS also significantly increased numbers of apoptotic nuclei in hepatocytes and expressions of proapoptotic regulators. Moreover, LPS sustained the low-grade activation of p38 MAPK and inhibited the expression of the upstream MAPK phosphatase 7. By applying selective inhibitors, we demonstrated that the activation of p38 MAPKs is required for neutrophil migration induced by superlow-dose LPS in vitro. Together, these data suggest that superlow-dose LPS may sustain the low-grade activation of p38 MAPKs and neutrophil infiltration, leading to the exacerbation of steatohepatitis.
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Affiliation(s)
- Honghui Guo
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0910, USA.,Department of Nutrition, Henry Fok School of Food Science and Engineering, Shaoguan University, Shaoguan 512005, China
| | - Na Diao
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0910, USA.,Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Ruoxi Yuan
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0910, USA
| | - Keqiang Chen
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0910, USA
| | - Shuo Geng
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0910, USA
| | - Mingsong Li
- Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Liwu Li
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0910, USA
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21
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Yuan R, Geng S, Chen K, Diao N, Chu HW, Li L. Low-grade inflammatory polarization of monocytes impairs wound healing. J Pathol 2016; 238:571-83. [PMID: 26690561 DOI: 10.1002/path.4680] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/06/2015] [Accepted: 12/02/2015] [Indexed: 01/05/2023]
Abstract
Impaired wound healing often accompanies low-grade inflammatory conditions, during which circulating levels of subclinical super-low-dose endotoxin may persist. Low-grade inflammatory monocyte polarization may occur during chronic inflammation and deter effective wound repair. However, little is understood about the potential mechanisms of monocyte polarization by sustained insult of subclinical super-low-dose endotoxin. We observed that super-low-dose endotoxin preferentially programmes a low-grade inflammatory monocyte state in vitro and in vivo, as represented by the elevated population of CD11b(+) Ly6C(high) monocytes and sustained expression of CCR5. Mechanistically, super-low-dose endotoxin caused cellular stress, altered lysosome function and increased the transcription factor IRF5. TUDCA, a potent inhibitor of cellular stress, effectively blocked monocyte polarization and improved wound healing in mice injected with super-low-dose endotoxin. Our data revealed the polarization of low-grade inflammatory monocytes by sustained endotoxin challenge, its underlying mechanisms and a potential intervention strategy. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Ruoxi Yuan
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Shuo Geng
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Keqiang Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Na Diao
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Hong Wei Chu
- Department of Medicine, National Jewish Health, Denver, CO, USA
| | - Liwu Li
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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22
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Affiliation(s)
- Kyoung-Bok Min
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Korea
| | - Jin-Young Min
- Institute of Health and Environment, School of Public Health, Seoul National University, Seoul, Korea
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23
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Kallio KAE, Hätönen KA, Lehto M, Salomaa V, Männistö S, Pussinen PJ. Endotoxemia, nutrition, and cardiometabolic disorders. Acta Diabetol 2015; 52:395-404. [PMID: 25326898 DOI: 10.1007/s00592-014-0662-3] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023]
Abstract
AIMS Circulating lipopolysaccharides (LPSs), associated with both infection and inflammation, may arise from the gastrointestinal tract microbiota, and the levels may be affected by daily nutrition. We investigated whether nutrient intake affects the association of serum LPS activity with prevalent obesity, metabolic syndrome (MetS), diabetes, and coronary heart disease (CHD) and with the risk of incident CHD events. METHODS The nutrition cohort (n = 2,452, mean age ± SD, 52.2 ± 10.1 years) of the FINRISK 1997 Study was followed up for 10 years. Information on macronutrient intake at baseline was collected from 24-h dietary recall. Serum endotoxin activities were determined by the Limulus amebocyte lysate assay. RESULTS LPS activity was associated directly with the total energy intake and indirectly with carbohydrate intake in lean, healthy subjects. High LPS was significantly associated with prevalent obesity, MetS, diabetes, and CHD events, independently of established risk factors, CRP, and total energy or nutrient intake. The ORs (95 % CI) were 1.49 (1.21-1.85, p < 0.001, Q2-4 vs. Q1) for obesity, 2.56 (1.97-3.32, p < 0.001, Q2-4 vs. Q1) for MetS, 1.94 (1.06-3.52, p = 0.031, Q2-4 vs. Q1) for CHD, and 1.01 (1.00-1.01, p = 0.032, LPS unit) for diabetes. In the follow-up, high LPS was significantly associated with the risk of CHD events with a hazard ratio of 1.88 (1.13-3.12, p = 0.013, Q2-4 vs. Q1). This association was independent of baseline established risk factors, diet, obesity, MetS, and diabetes. CONCLUSION A high serum LPS activity is strongly associated with cardiometabolic disorders, which supports the role of bacterial infections and immune response in their etiology.
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Affiliation(s)
- K A Elisa Kallio
- Institute of Dentistry, University of Helsinki, Biomedicum 1, P.O. Box 63, 00014, Helsinki, Finland,
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24
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Chen K, Geng S, Yuan R, Diao N, Upchurch Z, Li L. Super-low dose endotoxin pre-conditioning exacerbates sepsis mortality. EBioMedicine 2015; 2:324-333. [PMID: 26029736 PMCID: PMC4445878 DOI: 10.1016/j.ebiom.2015.03.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks. Super-low dose endotoxin pre-conditioning exacerbates, while higher dose endotoxin alleviates sepsis mortality. Super-low dose endotoxin reduces, while higher dose endotoxin facilitates neutrophil extracellular trap (NET) formation. Super-low dose endotoxin suppresses, while higher dose endotoxin induces ERK activation required for NET formation.
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Affiliation(s)
- Keqiang Chen
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Shuo Geng
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Ruoxi Yuan
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Na Diao
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Zachary Upchurch
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Liwu Li
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
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25
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Zaman GS, Zaman F. Relationship between postprandial endotoxemia in nonobese postmenopausal women and diabetic nonobese postmenopausal women. J Nat Sci Biol Med 2015; 6:89-93. [PMID: 25810642 PMCID: PMC4367076 DOI: 10.4103/0976-9668.149098] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background: We hypothesised that nonobese postmenopausal women (NoPoW) and diabetic NoPoW (DNoPoW) may be independently associated with postprandial endotoxemia. Materials and Methods: NoPoW and DNoPoW were evaluated for weight, eating habits, physical activity, body circumferences, fasting plasma glucose level, postprandial plasma glucose level, and insulin level. The lipopolysaccharide (LPS) levels and circulating LPS-binding protein (LBP) were determined in serum at fasting, 1 h, 2 h, 3 h, and 4 h after meal intake and their levels were co-related in 80 NoPoW and 80 DNoPoW. Results: Both DNoPoW group and NoPoW group showed a significant increase (P < 0.05) in LPS levels and circulating LBP in plasma after the meal intake, interestingly the increase was higher in the DNoPoW group. Conclusions: Elevated LPS and circulating LBP were associated significantly with DNoPoW group and NoPoW, especially after a meal intake. These findings suggested a role of LPS and LBP in postprandial systemic inflammation in DNoPoW group. Prospective studies are needed to confirm these results.
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Affiliation(s)
- Gaffar Sarwar Zaman
- Department of Clinical Biochemistry, Government College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia
| | - Fawzia Zaman
- Head of Operations and Quality Manager Ekopath Metropolis, Guwahati, Assam, India
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26
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Morris MC, Gilliam EA, Li L. Innate immune programing by endotoxin and its pathological consequences. Front Immunol 2015; 5:680. [PMID: 25610440 PMCID: PMC4285116 DOI: 10.3389/fimmu.2014.00680] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 12/16/2014] [Indexed: 12/24/2022] Open
Abstract
Monocytes and macrophages play pivotal roles in inflammation and homeostasis. Recent studies suggest that dynamic programing of macrophages and monocytes may give rise to distinct "memory" states. Lipopolysaccharide (LPS), a classical pattern recognition molecule, dynamically programs innate immune responses. Emerging studies have revealed complex dynamics of cellular responses to LPS, with high doses causing acute, resolving inflammation, while lower doses are associated with low-grade and chronic non-resolving inflammation. These phenomena hint at dynamic complexities of intra-cellular signaling circuits downstream of the Toll-like receptor 4 (TLR4). In this review, we examine pathological effects of varying LPS doses with respect to the dynamics of innate immune responses and key molecular regulatory circuits responsible for these effects.
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Affiliation(s)
- Matthew C. Morris
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Elizabeth A. Gilliam
- Virginia Tech Carillion School of Medicine and Research Institute, Roanoke, VA, USA
| | - Liwu Li
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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Armstrong MT, Rickles FR, Armstrong PB. Capture of lipopolysaccharide (endotoxin) by the blood clot: a comparative study. PLoS One 2013; 8:e80192. [PMID: 24282521 PMCID: PMC3839915 DOI: 10.1371/journal.pone.0080192] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/30/2013] [Indexed: 12/13/2022] Open
Abstract
In vertebrates and arthropods, blood clotting involves the establishment of a plug of aggregated thrombocytes (the cellular clot) and an extracellular fibrillar clot formed by the polymerization of the structural protein of the clot, which is fibrin in mammals, plasma lipoprotein in crustaceans, and coagulin in the horseshoe crab, Limulus polyphemus. Both elements of the clot function to staunch bleeding. Additionally, the extracellular clot functions as an agent of the innate immune system by providing a passive anti-microbial barrier and microbial entrapment device, which functions directly at the site of wounds to the integument. Here we show that, in addition to these passive functions in immunity, the plasma lipoprotein clot of lobster, the coagulin clot of Limulus, and both the platelet thrombus and the fibrin clot of mammals (human, mouse) operate to capture lipopolysaccharide (LPS, endotoxin). The lipid A core of LPS is the principal agent of gram-negative septicemia, which is responsible for more than 100,000 human deaths annually in the United States and is similarly toxic to arthropods. Quantification using the Limulus Amebocyte Lysate (LAL) test shows that clots capture significant quantities of LPS and fluorescent-labeled LPS can be seen by microscopy to decorate the clot fibrils. Thrombi generated in the living mouse accumulate LPS in vivo. It is suggested that capture of LPS released from gram-negative bacteria entrapped by the blood clot operates to protect against the disease that might be caused by its systemic dispersal.
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Affiliation(s)
- Margaret T. Armstrong
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Frederick R. Rickles
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
- Department of Medicine, School of Medicine, The George Washington University, Washington, DC, United States of America
| | - Peter B. Armstrong
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
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Ramezani A, Raj DS. The gut microbiome, kidney disease, and targeted interventions. J Am Soc Nephrol 2013; 25:657-70. [PMID: 24231662 DOI: 10.1681/asn.2013080905] [Citation(s) in RCA: 476] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The human gut harbors >100 trillion microbial cells, which influence the nutrition, metabolism, physiology, and immune function of the host. Here, we review the quantitative and qualitative changes in gut microbiota of patients with CKD that lead to disturbance of this symbiotic relationship, how this may contribute to the progression of CKD, and targeted interventions to re-establish symbiosis. Endotoxin derived from gut bacteria incites a powerful inflammatory response in the host organism. Furthermore, protein fermentation by gut microbiota generates myriad toxic metabolites, including p-cresol and indoxyl sulfate. Disruption of gut barrier function in CKD allows translocation of endotoxin and bacterial metabolites to the systemic circulation, which contributes to uremic toxicity, inflammation, progression of CKD, and associated cardiovascular disease. Several targeted interventions that aim to re-establish intestinal symbiosis, neutralize bacterial endotoxins, or adsorb gut-derived uremic toxins have been developed. Indeed, animal and human studies suggest that prebiotics and probiotics may have therapeutic roles in maintaining a metabolically-balanced gut microbiota and reducing progression of CKD and uremia-associated complications. We propose that further research should focus on using this highly efficient metabolic machinery to alleviate uremic symptoms.
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Affiliation(s)
- Ali Ramezani
- Division of Renal Diseases and Hypertension, The George Washington University, Washington DC
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Peng Q, Long CL, Malhotra S, Humphrey MB. A physical interaction between the adaptor proteins DOK3 and DAP12 is required to inhibit lipopolysaccharide signaling in macrophages. Sci Signal 2013; 6:ra72. [PMID: 23962980 DOI: 10.1126/scisignal.2003801] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNAX-activating protein of 12 kD (DAP12) is an immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptor protein found in myeloid cells and natural killer cells, and it couples to various receptors that mediate either cellular activation or inhibition. DAP12 inhibits Toll-like receptor (TLR) signaling, such as that of TLR4 in response to its ligand lipopolysaccharide (LPS), as well as cytokine responses by coupling to TREM2 (triggering receptor expressed on myeloid cells 2) at the plasma membrane. Understanding the mechanisms that inhibit inflammatory responses in macrophages is important for the development of therapies to treat inflammatory diseases. We show that inhibition of LPS responses by DAP12 is mediated by the adaptor protein DOK3 (downstream of kinase 3). DOK3 physically associated with the ITAM of DAP12 through its phosphotyrosine-binding domain. In response to LPS, DOK3 was phosphorylated in a DAP12- and Src-dependent manner, which led to translocation of phosphorylated DOK3 to the plasma membrane. DOK3-deficient cells exhibited increased production of proinflammatory cytokines and activation of extracellular signal-regulated kinase (ERK). Compared to wild-type mice, DOK3-deficient mice had increased susceptibility to challenge with a sublethal dose of LPS and produced increased serum concentrations of the inflammatory cytokine tumor necrosis factor-α (TNF-α). Together, these data suggest the mechanism by which DAP12 and TREM2 inhibit LPS signaling in macrophages to prevent inflammation.
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Affiliation(s)
- Qisheng Peng
- Key Laboratory for Zoonosis Research, Ministry of Education, Jilin University, Changchun 130062, China
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Deng H, Maitra U, Morris M, Li L. Molecular mechanism responsible for the priming of macrophage activation. J Biol Chem 2013; 288:3897-906. [PMID: 23264622 PMCID: PMC3567643 DOI: 10.1074/jbc.m112.424390] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 12/10/2012] [Indexed: 12/13/2022] Open
Abstract
Host macrophages can be preprogrammed into opposing primed or tolerant states depending upon the nature and quantities of external stimulants. The paradigm of priming and tolerance has significant implications in the pathogenesis and resolution of both acute and chronic inflammatory diseases. However, the responsible mechanisms are not well understood. Here, we report that super low dose bacterial endotoxin lipopolysaccharide (LPS), as low as 5 pg/ml, primes the expression of proinflammatory mediators in macrophages upon a second high dose LPS challenge (100 ng/ml), although 5 pg/ml LPS itself does not trigger noticeable macrophage activation. Mice primed with super low dose LPS (0.5 μg/kg body weight) in vivo experience significantly elevated mortality following a second hit of high dose LPS as compared with saline-primed control mice. Mechanistically, we demonstrate that LPS primes macrophages by removing transcriptional suppressive RelB through interleukin receptor-associated kinase 1 and Tollip (Toll-interacting protein)-dependent mechanisms. This is in sharp contrast to the well documented RelB stabilization and induction by high dose LPS, potentially through the phosphoinositide 3-kinase (PI3K) pathway. Super low dose and high dose LPS cause opposing modulation of interleukin receptor-associated kinase 1 and PI3K pathways and lead to opposing regulation of RelB. The pathway switching induced by super low versus high dose LPS underscores the importance of competing intracellular circuitry during the establishment of macrophage priming and tolerance.
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Affiliation(s)
- Hui Deng
- From the Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0910
| | - Urmila Maitra
- From the Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0910
| | - Matt Morris
- From the Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0910
| | - Liwu Li
- From the Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0910
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Maitra U, Li L. Molecular mechanisms responsible for the reduced expression of cholesterol transporters from macrophages by low-dose endotoxin. Arterioscler Thromb Vasc Biol 2012; 33:24-33. [PMID: 23117655 DOI: 10.1161/atvbaha.112.300049] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Atherosclerosis is characterized as a chronic inflammatory condition that involves cholesterol deposition in arteries. Together with scavenger receptor B1 (SR-B1), the ATP-binding cassette transporters ABCA1 and ABCG1 are the major components of macrophage cholesterol efflux. Recent studies have shown that low-grade inflammation plays a distinct regulatory role in the expression of SR-B1 and ABCA1/ABCG1. However, the mechanisms linking low-grade inflammation and cholesterol accumulation are poorly understood. METHODS AND RESULTS Using primary bone-marrow-derived macrophages, we demonstrate that subclinical low-dose lipopolysaccharide potently reduces the expression of SR-B1 and ABCA1/ABCG1, as well as cholesterol efflux from macrophages through interleukin-1 receptor-associated kinase 1 and Toll-interacting-protein. Low-dose lipopolysaccharide downregulates the nuclear levels of retinoic acid receptor-α, leading to their reduced binding to the promoters of SR-B1 and ABCA1/ABCG1. We observe that glycogen synthase kinase 3β activation by low-dose lipopolysaccharide through interleukin-1 receptor-associated kinase 1 and Toll-interacting-protein is responsible for reduced levels of retinoic acid receptor-α, and reduced expression of SR-B1 and ABCA1/ABCG1. Interleukin-1 receptor-associated kinase M, however, counteracts the function of interleukin-1 receptor associated kinase 1. CONCLUSIONS Collectively, our data reveal a novel intracellular network regulated by low-dose endotoxemia that disrupts cholesterol efflux from macrophages and leads to the pathogenesis of atherosclerosis.
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MESH Headings
- ATP Binding Cassette Transporter 1
- ATP Binding Cassette Transporter, Subfamily G, Member 1
- ATP-Binding Cassette Transporters/drug effects
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Apolipoprotein A-I/metabolism
- Atherosclerosis/chemically induced
- Atherosclerosis/metabolism
- Binding Sites
- Cells, Cultured
- Cholesterol/metabolism
- Cholesterol, HDL/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation
- Endotoxins/pharmacology
- Endotoxins/toxicity
- Foam Cells/drug effects
- Foam Cells/metabolism
- Glycogen Synthase Kinase 3/genetics
- Glycogen Synthase Kinase 3/metabolism
- Glycogen Synthase Kinase 3 beta
- Interleukin-1 Receptor-Associated Kinases/genetics
- Interleukin-1 Receptor-Associated Kinases/metabolism
- Intracellular Signaling Peptides and Proteins/metabolism
- Lipoproteins/drug effects
- Lipoproteins/genetics
- Lipoproteins/metabolism
- Macrophages/drug effects
- Macrophages/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Promoter Regions, Genetic
- Receptors, Retinoic Acid/metabolism
- Retinoic Acid Receptor alpha
- Scavenger Receptors, Class B/drug effects
- Scavenger Receptors, Class B/genetics
- Scavenger Receptors, Class B/metabolism
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Affiliation(s)
- Urmila Maitra
- Laboratory of Inflammation Biology, Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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32
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The surface lipids of non-tuberculous mycobacteria suppress production of phagocyte activating cytokines in human peripheral blood mononuclear cells. Microbes Infect 2012; 14:768-77. [DOI: 10.1016/j.micinf.2012.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 03/08/2012] [Accepted: 03/18/2012] [Indexed: 11/20/2022]
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Maitra U, Deng H, Glaros T, Baker B, Capelluto DG, Li Z, Li L. Molecular mechanisms responsible for the selective and low-grade induction of proinflammatory mediators in murine macrophages by lipopolysaccharide. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:1014-23. [PMID: 22706082 PMCID: PMC3392521 DOI: 10.4049/jimmunol.1200857] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Low-dose endotoxemia is prevalent in humans with adverse health conditions, and it correlates with the pathogenesis of chronic inflammatory diseases such as atherosclerosis, diabetes, and neurologic inflammation. However, the underlying molecular mechanisms are poorly understood. In this study, we demonstrate that subclinical low-dose LPS skews macrophages into a mild proinflammatory state, through cell surface TLR4, IL-1R-associated kinase-1, and the Toll-interacting protein. Unlike high-dose LPS, low-dose LPS does not induce robust activation of NF-κB, MAPKs, PI3K, or anti-inflammatory mediators. Instead, low-dose LPS induces activating transcription factor 2 through Toll-interacting protein-mediated generation of mitochondrial reactive oxygen species, allowing mild induction of proinflammatory mediators. Low-dose LPS also suppresses PI3K and related negative regulators of inflammatory genes. Our data reveal novel mechanisms responsible for skewed and persistent low-grade inflammation, a cardinal feature of chronic inflammatory diseases.
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Affiliation(s)
- Urmila Maitra
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061-0910
| | - Hui Deng
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061-0910
| | - Trevor Glaros
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061-0910
| | - Bianca Baker
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061-0910
| | | | - Zihai Li
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC29425
| | - Liwu Li
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061-0910
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Hirayama T, Tamaki Y, Takakubo Y, Iwazaki K, Sasaki K, Ogino T, Goodman SB, Konttinen YT, Takagi M. Toll-like receptors and their adaptors are regulated in macrophages after phagocytosis of lipopolysaccharide-coated titanium particles. J Orthop Res 2011; 29:984-92. [PMID: 21308757 DOI: 10.1002/jor.21369] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/03/2011] [Indexed: 02/04/2023]
Abstract
Macrophages phagocytose metallic wear particles and produce mediators, which can induce cellular host response and aseptic implant loosening. Lipopolysaccharide (LPS) on the wear debris can stimulate macrophages via Toll-like receptor 4 (TLR4) and enhance the response. However, the precise functional role and interaction of TLRs and their adaptor molecules is still unclear. Rat bone marrow macrophages were stimulated with titanium particle (Ti) coated by LPS (Ti/LPS+) and LPS-free Ti (Ti/LPS-). mRNA levels of cytokines, TLRs and their adaptor molecules were measured using real time PCR. mRNA levels of TNF-α, IL-1β, and IL-6 increased in Ti/LPS+ than Ti/LPS-. In contrast, mRNA levels of TLR4, TLR5, and TLR9 decreased in Ti/LPS+ compared to Ti/LPS-. mRNA levels of MyD88, IRAK1, IRAK4 decreased gradually, and TRAF6 underwent an initial transient increase, followed by suppression in Ti/LPS+. However, mRNA levels of TLR2 and IRAK2 increased after phagocytosis of Ti/LPS+ than Ti/LPS-. The increased expressions of proinflammatory cytokines found in Ti/LPS+ indicated that their productions cytokines could be enhanced by phagocytosis of LPS-coated particles. Subsequent down-regulation of TLR4, TLR5, TLR9, MyD88, IRAK1, and IRAK4 suggests that self-protective mechanisms to regulate excessive host responses are activated in macrophages. Increase of TLR2 and IRAK2 and a transient increase of TRAF6 in Ti/LPS+ suggest that another possible pathway to modulate TLR-mediated cellular response to prolong inflammatory response in foreign body reaction of aseptic loosening. This down- and/or up-regulation of the potential TLR-mediated responses to LPS-coated particles reflects the proactive behavior of effector cells.
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Affiliation(s)
- Tomoyuki Hirayama
- Department of Orthopaedic Surgery, Yamagata University School of Medicine, 2-2-2 Iida Nishi, Yamagata 990-9585, Japan.
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Maitra U, Gan L, Chang S, Li L. Low-Dose Endotoxin Induces Inflammation by Selectively Removing Nuclear Receptors and Activating CCAAT/Enhancer-Binding Protein δ. THE JOURNAL OF IMMUNOLOGY 2011; 186:4467-73. [DOI: 10.4049/jimmunol.1003300] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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36
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Manco M, Putignani L, Bottazzo GF. Gut microbiota, lipopolysaccharides, and innate immunity in the pathogenesis of obesity and cardiovascular risk. Endocr Rev 2010; 31:817-44. [PMID: 20592272 DOI: 10.1210/er.2009-0030] [Citation(s) in RCA: 324] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Compelling evidence supports the concepts that gut microbiota actively promotes weight gain and fat accumulation and sustains, indirectly, a condition of low-grade inflammation, thus enhancing the cardiovascular risk. Fewer Bacteroidetes and more Firmicutes seem to characterize the gut microbiota of obese people as compared with that of lean individuals. This difference translates into an increased efficiency of microbiota of obese individuals in harvesting energy from otherwise indigestible carbohydrates. Furthermore, the microbiota also seems able to favor fat accumulation. Indeed, studies performed in germ-free animals have demonstrated that conventionalization of sterile intestine with gut microbiota is associated with an enhanced expression of various lipogenic genes in different tissues, i.e., hepatic, adipose, and muscle tissues. Finally, the microbiota favors systemic exposure to the lipopolysaccharides (LPSs), large glycolipids derived from the outer membrane of Gram-negative bacteria. LPSs can cause a condition of "metabolic endotoxemia" characterized by low-grade inflammation, insulin resistance, and augmented cardiovascular risk. LPSs are a powerful trigger for the innate immune system response. Upon binding to the Toll-like receptor 4 and its coreceptors, LPSs trigger a cascade of responses ultimately resulting in the release of proinflammatory molecules that interfere with modulation of glucose and insulin metabolism, promote development and rupture of the atherosclerotic plaque, and favor progression of fatty liver disease to steatohepatitis. This review gives a comprehensive breakdown of the interaction among gut microbiota, LPSs, and the innate immune system in the development of obesity and promotion of an individual's cardiovascular risk.
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Affiliation(s)
- Melania Manco
- Bambino Gesù Hospital, Instituto di Ricovero e Cura a Carattere Scientifico, Piazza San Onofrio 4, I-00165 Rome, Italy.
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Caesar R, Fåk F, Bäckhed F. Effects of gut microbiota on obesity and atherosclerosis via modulation of inflammation and lipid metabolism. J Intern Med 2010; 268:320-8. [PMID: 21050286 DOI: 10.1111/j.1365-2796.2010.02270.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent studies have revealed a close relationship between inflammatory and metabolic pathways, and inflammation is now recognized to have a major role in obesity and metabolic diseases such as insulin resistance and atherosclerosis. The human body is home to a large number of distinct microbial communities, with the densest population in the distal gut (the gut microbiota). Bacteria have long been known to activate inflammatory pathways, and recent data demonstrate that the gut microbiota may affect lipid metabolism and function as an environmental factor that influences the development of obesity and related diseases. Here, we review how the gut microbiota may affect metabolic diseases by activating the innate immune system.
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Affiliation(s)
- R Caesar
- Department of Molecular and Clinical Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research/Wallenberg Laboratory, University of Gothenburg, Gothenburg, Sweden
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Shimada K, Daida H, Ma-Krupa W, Goronzy JJ, Weyand CM. Lipopolysaccharide, CD14 and Toll-like receptors: an emerging link between innate immunity and atherosclerotic disease. Future Cardiol 2010; 1:657-74. [PMID: 19804106 DOI: 10.2217/14796678.1.5.657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Atherosclerosis and its clinical complications are now understood to be an inflammatory syndrome in which an ongoing systemic inflammatory response is combined with the accumulation of immune cells in the atherosclerotic plaque. Both arms of the immune system, innate and adaptive, have been implicated in contributing to essentially all stages of atherosclerosis, from initiation to progression and, ultimately, atherothrombotic complications. Innate immunity is the first line of defense against invading microorganisms. The recognition units of the innate immune system are designed to respond to molecular patterns shared by a variety of infectious microorganisms, such as bacterial lipopolysaccharide. Numerous basic and clinical studies have provided evidence that responsiveness to lipopolysaccharide may be correlated to the risk of atherosclerotic disease. The molecular basis of this connection appears to lie in Toll-like receptors that are expressed on cells of the innate immune system, bind to lipopolysaccharide, and thus determine the strength of antibacterial immune responses in the host. Variations in the function of Toll-like receptors and their signaling pathways are now suspected to play a critical role in determining the risk of atherosclerosis. This review summarizes recent research advances exploring the role of innate immunity, particularly lipopolysaccharide, CD14 and Toll-like receptors, in the initiation and development of atherosclerotic disease.
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Affiliation(s)
- Kazunori Shimada
- Juntendo University School of Medicine, Division of Cardiology, Department of Internal Medicine, 2-1-1 Hongo Bunkyo-ku, Tokyo 113-8421, Japan.
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Complex links between dietary lipids, endogenous endotoxins and metabolic inflammation. Biochimie 2010; 93:39-45. [PMID: 20433893 DOI: 10.1016/j.biochi.2010.04.016] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Accepted: 04/21/2010] [Indexed: 12/29/2022]
Abstract
Metabolic diseases such as obesity are characterized by a subclinical inflammatory state that contributes to the development of insulin resistance and atherosclerosis. Recent reports also indicate that (i) there are alterations of the intestinal microbiota in metabolic diseases and (ii) absorption of endogenous endotoxins (namely lipopolysaccharides, LPS) can occur, particularly during the digestion of lipids. The aim of the present review is to highlight recently gained knowledge regarding the links between high fat diets, lipid digestion, intestinal microbiota and metabolic endotoxemia & inflammation.
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Kallio KAE, Buhlin K, Jauhiainen M, Keva R, Tuomainen AM, Klinge B, Gustafsson A, Pussinen PJ. Lipopolysaccharide associates with pro-atherogenic lipoproteins in periodontitis patients. Innate Immun 2009; 14:247-53. [PMID: 18669610 DOI: 10.1177/1753425908095130] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
INTRODUCTION Periodontitis patients are known to suffer from endotoxemia, which may be among the major risk factors for atherosclerosis. In health, lipopolysaccharide (LPS) is mainly carried with high density lipoprotein (HDL) particles. Shift of LPS toward lipoproteins with lower densities may result in less effective endotoxin scavenging. Our aim was to determine plasma LPS activity and lipoprotein-distribution before and after treatment in periodontitis patients. PATIENTS AND METHODS Very low and intermediate density (VLDL-IDL), low density (LDL), HDL 2, HDL3, and lipoprotein-deficient plasma (LPDP) were isolated by sequential ultracentrifugation. Patients included 34 subjects aged 53.5 +/- 8.3 years, before and 6 months after periodontal treatment. RESULTS The mean LPS distribution decreased among lipoprotein classes as follows: VLDL-IDL 41.3 +/- 12.1%, LPDP 25.0 +/- 7.0%, HDL3 13.1 +/- 5.2%, LDL 11.5 +/- 3.7%, and HDL2 9.2 +/- 2.8%. Plasma and VLDL-IDL-associated LPS correlated positively, and LDL- and HDL-associated LPS negatively with clinical periodontal parameters and plasma cytokine concentrations. Mean plasma LPS activity increased after periodontal treatment from 44.0 +/- 17.0 to 55.7 +/- 24.2 EU/ml (P = 0.006). No significant changes were found in LPS lipoprotein distribution and lipoprotein compositions after the treatment. CONCLUSIONS Endotoxemia increases with severity of periodontitis. In periodontitis, LPS associates preferentially with the pro-atherogenic VLDL-IDL fraction. Periodontal treatment has only minor effects on plasma LPS activity or distribution, which reflects persistence of the disease.
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Affiliation(s)
- K A Elisa Kallio
- Institute of Dentistry, University of Helsinki, and Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki, Finland.
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Chlamydial lipopolysaccharide (cLPS) is present in atherosclerotic and aneurysmal arterial wall--cLPS levels depend on disease manifestation. Cardiovasc Pathol 2009; 19:48-54. [PMID: 19150246 DOI: 10.1016/j.carpath.2008.10.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 10/02/2008] [Accepted: 10/28/2008] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The role of Chlamydia pneumoniae in peripheral atherosclerosis disease and abdominal aortic aneurysm (AAA) remains unclear. Chlamydial lipopolysaccharide (cLPS) detection is a method used conventionally in routine chlamydial diagnosis of gynecological or ophthalmic samples. METHODS We compared cLPS concentrations, as well as other markers of bacterial load, in plaques and sera of patients operated on for carotid artery stenosis (n=110), aorto-occlusive disease (n=22), or AAAs (n=50) at the Helsinki University Central Hospital. RESULTS The median levels of cLPS in plaques were 2.28, 0.80, and 0.29 ng/ml in AAA, aorto-occlusive disease, and carotid artery stenosis patients, respectively (P<.001, Kruskal-Wallis). cLPS in serum correlated with LPS binding protein levels (Spearman's rho=0.52, P<.001), suggesting that the presence of chlamydiae is sufficient to produce an innate immune response reaction in these patients. Serum inflammatory markers interleukin 6 and highly sensitive C-reactive protein also correlate with cLPS (Spearman's rho=0.42 and 0.51, respectively, P<.001). CONCLUSIONS cLPS is present in arterial disease, and the potential role of C. pneumoniae in the pathogenesis of both peripheral atherosclerosis disease and AAA should not be forgotten. cLPS has a positive correlation with serum inflammatory markers, but this is no proof of a causal association.
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Asanuma Y, Oeser A, Stanley E, Bailey DG, Shintani A, Stein CM. Effects of C-reactive Protein and Homocysteine on Cytokine Production: Modulation by Pravastatin. ACTA ACUST UNITED AC 2008; 1:14-22. [PMID: 20157364 PMCID: PMC2817441 DOI: 10.1111/j.1753-5174.2007.00003.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE: C-reactive protein (CRP) and homocysteine are markers of cardiovascular risk that may have inflammatory effects. HMG coenzyme A reductase inhibitors (statins) have anti-inflammatory effects in vitro, but it is not clear if such responses in vivo are secondary to lipid lowering. We examined the hypothesis that CRP and homocysteine would stimulate cytokine release in human whole blood and that short-term treatment with a statin would inhibit it. METHODS: The time course of IL-6 and MCP-1 production was determined in whole blood incubated with saline, 1 microg/mL lipopolysaccaride (LPS), 50 and 100 microM/L DL-homocysteine, and 5 microg/mL human recombinant CRP for 24 hours at 37 degrees C under 5% CO(2) atmosphere. Cytokine responses were determined in blood drawn from 15 healthy volunteers before and after administration of pravastatin 40 mg daily for 2 days. RESULTS: Both human recombinant CRP and LPS significantly increased the production of IL-6 and MCP-1 in whole blood samples more than 4-fold (P < 0.001) but homocysteine did not. Oral administration of pravastatin, 40mg daily for 2 days, decreased CRP-stimulated IL-6 production by approximately 20% (P = 0.02) 6 hours after incubation, but did not affect MCP-1 production (P = 0.69). Pravastatin treatment did not affect LPS-stimulated MCP-1 but increased IL-6 modestly. CONCLUSIONS: CRP stimulated the production of the proatherogenic mediators MCP-1 and IL-6 in human whole blood, but homocysteine did not. CRP-stimulated production of IL-6, but not MCP-1, was modestly attenuated by short-term treatment with pravastatin.
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Affiliation(s)
- Yu Asanuma
- Division of Rheumatology and Applied Immunology, Saitama Medical UniversitySaitama, Japan
- Division of Clinical Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
| | - Annette Oeser
- Division of Clinical Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
| | - Eran Stanley
- Division of Clinical Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
| | - David G Bailey
- Department of Medicine, Lawson Health Research Institute Health Sciences Centre LondonOntario, Canada
| | - Ayumi Shintani
- Division of General Internal Medicine, Vanderbilt University School of MedicineNashville, TN, USA
| | - C Michael Stein
- Division of Clinical Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
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Erridge C, Attina T, Spickett CM, Webb DJ. A high-fat meal induces low-grade endotoxemia: evidence of a novel mechanism of postprandial inflammation. Am J Clin Nutr 2007; 86:1286-92. [PMID: 17991637 DOI: 10.1093/ajcn/86.5.1286] [Citation(s) in RCA: 521] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Bacterial endotoxin is a potently inflammatory antigen that is abundant in the human gut. Endotoxin circulates at low concentrations in the blood of all healthy individuals, although elevated concentrations are associated with an increased risk of atherosclerosis. OBJECTIVE We sought to determine whether a high-fat meal or smoking increases plasma endotoxin concentrations and whether such concentrations are of physiologic relevance. DESIGN Plasma endotoxin and endotoxin neutralization capacity were measured for 4 h in 12 healthy men after no meal, 3 cigarettes, a high-fat meal, or a high-fat meal with 3 cigarettes by using the limulus assay. RESULTS Baseline endotoxin concentrations were 8.2 pg/mL (interquartile range: 3.4-13.5 pg/mL) but increased significantly (P < 0.05) by approximately 50% after a high-fat meal or after a high-fat meal with cigarettes but not after no meal or cigarettes alone. These results were validated by the observations that a high-fat meal with or without cigarettes, but not no meal or smoking, also significantly (P < 0.05) reduced plasma endotoxin neutralization capacity, which is an indirect measure of endotoxin exposure. Human monocytes, but not aortic endothelial cells, were responsive to transient (30 s) or low-dose (10 pg/mL) exposure to endotoxin. However, plasma from whole blood treated with as little as 10 pg endotoxin/mL increased the endothelial cell expression of E-selectin, at least partly via tumor necrosis factor-alpha-induced cellular activation. CONCLUSIONS Low-grade endotoxemia may contribute to the postprandial inflammatory state and could represent a novel potential contributor to endothelial activation and the development of atherosclerosis.
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Affiliation(s)
- Clett Erridge
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom.
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44
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Tremblay T, Aubin E, Lemieux R, Bazin R. Picogram doses of lipopolysaccharide exacerbate antibody-mediated thrombocytopenia and reduce the therapeutic efficacy of intravenous immunoglobulin in mice. Br J Haematol 2007; 139:297-302. [PMID: 17897306 DOI: 10.1111/j.1365-2141.2007.06777.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exacerbation of antibody-mediated thrombocytopenia following infection with viruses has recently been demonstrated in a mouse model of the disease. The phenomenon was caused by an increased activation of phagocytes through gamma-interferon secretion in response to infection. Endotoxins from Gram-negative bacteria are also known to be potent activators of phagocytic cells. The objective of the present work was to determine whether lipopolysaccharide (LPS) could exacerbate antibody-mediated thrombocytopenia in vivo and so alter the therapeutic efficacy of intravenous immunoglobulin (IVIg), using a mouse model of thrombocytopenia. Very low doses of LPS (picogram range) and of anti-platelet antibodies (nanogram range), which did not induce thrombocytopenia individually, could synergize in vivo, resulting in significant decreases in platelet counts. The therapeutic efficacy of IVIg in antibody-mediated thrombocytopenia was significantly reduced in presence of LPS. These in vivo observations further support a role for bacterial infections in the aetiology of immune thrombocytopenic purpura (ITP) and may contribute to better understand the recognized lack of efficacy of IVIg in a significant proportion of patients with ITP.
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Affiliation(s)
- Tony Tremblay
- Department of Research and Development, Héma-Québec, QC, Canada
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45
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Pussinen PJ, Tuomisto K, Jousilahti P, Havulinna AS, Sundvall J, Salomaa V. Endotoxemia, immune response to periodontal pathogens, and systemic inflammation associate with incident cardiovascular disease events. Arterioscler Thromb Vasc Biol 2007; 27:1433-9. [PMID: 17363692 DOI: 10.1161/atvbaha.106.138743] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE In periodontitis, overgrowth of gram-negative bacteria may cause endotoxemia and systemic inflammation leading to cardiovascular diseases (CVD). We investigated in a prospective study the associations of serum endotoxin, antibodies to periodontal pathogens, and inflammation markers with the risk of incident CVD. METHODS AND RESULTS The FINRISK 1992 cohort of 6051 individuals was followed up for 10 years. We examined 185 incident CVD events and a control cohort of 320 individuals using a prospective case-cohort design. High antibody response to periodontal pathogens independently predicted incident CVD events with hazard ratios (HR, quartile 4 versus quartiles 1 to 3, 95% CI) of 1.87 (1.13 to 3.08). The subjects with a high antibody response and high CRP or interleukin (IL)-6 had multivariate-adjusted HRs of 3.01 (1.27 to 7.09) and 3.11 (1.42 to 6.83) compared with low-responders, respectively. The corresponding HRs for high endotoxin concentration were 1.82 (1.22 to 2.73, alone), 3.92 (1.99 to 7.74, with CRP), 3.54 (1.78 to 7.03, with IL-6), and 2.26 (1.13 to 4.52, with tumor necrosis factor (TNF)-alpha) after adjusting for age and gender. These associations were abolished after adjusting for serum lipids. High endotoxin/HDL ratio, however, had a multivariate-adjusted HR of 1.92 (1.19 to 3.08) for CVD events. CONCLUSIONS Our results suggest that the exposure to periodontal pathogens or endotoxin induces systemic inflammation leading to increased risk for CVD.
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Affiliation(s)
- Pirkko J Pussinen
- Institute of Dentistry, University of Helsinki, Haartmaninkatu 8, PO Box 63, FI-00014 Helsinki, Finland.
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Boekholdt SM, Agema WRP, Peters RJG, Zwinderman AH, van der Wall EE, Reitsma PH, Kastelein JJP, Jukema JW. Variants of toll-like receptor 4 modify the efficacy of statin therapy and the risk of cardiovascular events. Circulation 2003; 107:2416-21. [PMID: 12742999 DOI: 10.1161/01.cir.0000068311.40161.28] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Atherosclerosis is increasingly considered to be a chronic inflammatory process. We examined whether genetic variants of the toll-like receptor 4 (TLR4), which are correlated with impaired innate immunity and with progression of carotid atherosclerosis, are also associated with coronary atherosclerosis and predict the risk of cardiovascular events. METHODS AND RESULTS Two polymorphisms of the TLR4 gene (Asp299Gly and Thr399Ile) were determined in 655 men with angiographically documented coronary atherosclerosis. All patients participated in a prospective cholesterol-lowering trial evaluating the effect on coronary artery disease and were randomly assigned to either pravastatin or placebo for 2 years. There were no significant differences between genetically defined subgroups with respect to baseline risk factors, treatment, or in-trial changes of lipid, lipoprotein, or angiographic measurements. Genotype was not associated with progression of atherosclerosis. In the pravastatin group, 299Gly carriers had a lower risk of cardiovascular events during follow-up than noncarriers (2.0% versus 11.5%, P=0.045). Among noncarriers, pravastatin reduced the risk of cardiovascular events from 18.1% to 11.5% (P=0.03), whereas among 299Gly carriers this risk was strikingly reduced from 29.6% to 2.0% (P=0.0002, P=0.025 for interaction). CONCLUSIONS Among symptomatic men with documented coronary artery disease, the TLR4 Asp299Gly polymorphism was associated with the risk of cardiovascular events. This variant also modified the efficacy of pravastatin in preventing cardiovascular events, such that carriers of the variant allele had significantly more benefit from pravastatin treatment.
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Affiliation(s)
- S Matthijs Boekholdt
- Leiden University Medical Center, Department of Cardiology C5-P, Albinusdreef 2, PO Box 9600, 2300 RC Leiden, The Netherlands.
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Nádházi Z, Takáts A, Offenmüller K, Bertók L. Plasma endotoxin level of healthy donors. Acta Microbiol Immunol Hung 2002; 49:151-7. [PMID: 12073822 DOI: 10.1556/amicr.49.2002.1.15] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The plasma level of endotoxin was determined in 116 healthy blood donors. After a routine physical and laboratory investigations the endotoxin level was determined with Limulus amebocyte lysate assay (LAL-test) by the chromogenic kinetic method of Bio-Whittaker Co. (USA). Its sensitivity was 0.005-50 EU/ml. The plasma level of endotoxin in most of the healthy donors was less than 1 EU/ml (in the range of 0.01-1.0 EU/ml), but always measurable. The average +/- S.D. was 0.128 +/- 0.215 EU/ml. Because of the high standard deviation and high range of values, the data were distributed into two groups with the means of 0.05 +/- 0.022 EU/ml and 0.294 +/- 0.186 EU/ml. The difference between the groups was significant (p < 0.001). In conclusion, endotoxin can be measured in plasma of healthy individuals.
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Affiliation(s)
- Z Nádházi
- Second Department of Internal Medicine, Faculty of General Medicine, Semmelweis University, PO Box 277, H-1444 Budapest, Hungary
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Kaser A, Ludwiczek O, Waldenberger P, Jaschke W, Vogel W, Tilg H. Endotoxin and its binding proteins in chronic liver disease: the effect of transjugular intrahepatic portosystemic shunting. LIVER 2002; 22:380-7. [PMID: 12390473 DOI: 10.1034/j.1600-0676.2002.01666.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Gut-derived endotoxin is insufficiently cleared by the diseased liver, and thus, is elevated in plasma of patients with chronic liver disease (CLD). Endotoxin action might be modified by binding to soluble CD14 (sCD14) and lipopolysaccharide-binding protein (LBP), both of which have not yet been sufficiently studied in CLD. METHODS Endotoxin, sCD14 and LBP have been determined in peripheral blood of 72 patients and 39 control subjects, and in portal and hepatic venous blood of 12 patients during transjugular intrahepatic portosystemic shunt (TIPS) implantation. RESULTS Peripheral endotoxin (average 3-fold increased compared to controls), LBP, and sCD14 plasma levels were elevated in chronic liver disease irrespective of Child stage m, preserve/absence of cirrhosis or aetiology. LBP, and sCD14. Furthermore, endotoxin levels in the portal vein (38.1 +/- 6.1 pg/ml) were only slightly elevated compared to the hepatic vein (29.2 +/- 4.4 pg/ml), and peripheral endotoxin levels did not increase after TIPS. CONCLUSIONS Decreased hepatocellular function rather than hepatic blood shunting might be responsible for endotoxemia. The elevation in LBP and sCD14 levels may be a consequence of endotoxemia.
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Affiliation(s)
- Arthur Kaser
- Division of Gastroenterology and Hepatology, Department of Medicine, University Hospital Innsbruck, Austria
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van Tellingen A, Grooteman MPC, Pronk R, van Loon J, Vervloet MG, ter Wee PM, Nubé MJ. Lipopolysaccharide concentrations during superflux dialysis using unfiltered bicarbonate dialysate. ASAIO J 2002; 48:383-8. [PMID: 12141468 DOI: 10.1097/00002480-200207000-00010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In the present report, the design of a new dialysate delivery system to produce low to moderately contaminated dialysate is described. In addition, the first data on bacterial counts and lipopolysaccharide (LPS) concentrations in both the dialysate and the blood during hemodialysis (HD) with superflux dialyzers are presented. In this prospective study, 37 patients were randomized into two consecutive periods of 12 weeks to HD with a high flux polysulfon (PS), a superflux PS, a superflux cellulosic tri-acetate (CTA) or a superflux CTA dialyzer with filtered dialysate (CTAf), resulting in 74 periods in which measurements were obtained. Filtered dialysate showed significantly lower bacterial counts, if compared with nonfiltered dialysate (p < 0.001). As for LPS, marked differences were not observed between filtered and nonfiltered dialysate, whereas mean plasma LPS concentrations were below the value of the dialysate at all time points (p < 0.001). Plasma LPS concentrations decreased significantly during HD with all four modalities (F 60: t0 0.032+/-0.005, t180 0.026+/-0.009 endotoxin units (EU)/ml, p = 0.001; F 500S, t0 0.031+/-0.004, t180 0.027+/-0.005 EU/ml, p = 0.001; Tricea 150G: t0 0.032+/-0.004, t180 0.025+/-0.005 EU/ml, p < 0.001; and Tricea 150Gf: t0 0.034+/-0.007, t180 0.025+/-0.006 EU/ml, p < 0.001). During HD with highly permeable dialyzers and moderately contaminated dialysate, plasma LPS concentrations decreased significantly, irrespective of the material used (PS or CTA), the flux characteristics of the devices (high flux or superflux), or the presence of a bacterial filter.
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50
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Geerts SO, Nys M, De MP, Charpentier J, Albert A, Legrand V, Rompen EH. Systemic release of endotoxins induced by gentle mastication: association with periodontitis severity. J Periodontol 2002; 73:73-8. [PMID: 11846202 DOI: 10.1902/jop.2002.73.1.73] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Periodontitis has recently been identified as a potential risk factor for systemic pathologies such as cardiovascular disease, the hypothesis being that periodontal pockets could release pro-inflammatory bacterial components, for instance endotoxins, into the bloodstream. It is known that the oral cavity can be a source of circulating bacteria, but this has never been shown for bacterial endotoxins, and no evidence exists so far that the risk of systemic injury is related to the severity of periodontitis. The aim of the present study was to test the influence of gentle mastication on the occurrence of endotoxemia in patients with or without periodontal disease. METHODS A total of 67 subjects were periodontally examined and grouped according to their periodontal status. This classification was based on an original index of severity of periodontal disease (periodontal index for risk of infectiousness, PIRI) aimed at reflecting the individual risk of systemic injury from the periodontal niches. Thus, the patients were classified into 3 risk groups: low, PIRI = 0; n = 25; moderate, 1 < or = PIRI < or = 5, n = 27; and high 6 < or = PIRI < or = 10, n = 15. Blood samples were collected before and 5 to 10 minutes after a standardized session of gentle mastication for detection of circulating endotoxins. Blood samples were tested with a chromogenic limulus amoebocyte lysate assay. RESULTS Overall, blood levels of endotoxin after mastication were found to be significantly higher than before mastication (0.89 +/- 3.3 pg/ml versus 3.0 +/- 5.8 pg/ml; P= 0.0002). Likewise, the incidence of positive endotoxemia rose from 6% before mastication to 24% after mastication (P = 0.001). When accounting for the PIRI index, endotoxin levels and positive endotoxemia proved to be significantly higher in patients with severe periodontal disease than in the subjects with low or moderate periodontitis. CONCLUSIONS Gentle mastication is able to induce the release of bacterial endotoxins from oral origin into the bloodstream, especially when patients have severe periodontal disease. This finding suggests that a diseased periodontium can be a major and underestimated source of chronic, or even permanent, release of bacterial pro-inflammatory components into the bloodstream.
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Affiliation(s)
- Sabine O Geerts
- Department of Periodontology-Bucco-Dental Surgery, University of Liège, Belgium
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