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Ree IMC, Fustolo-Gunnink SF, Bekker V, Fijnvandraat KJ, Steggerda SJ, Lopriore E. Thrombocytopenia in neonatal sepsis: Incidence, severity and risk factors. PLoS One 2017; 12:e0185581. [PMID: 28977011 PMCID: PMC5627935 DOI: 10.1371/journal.pone.0185581] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 09/15/2017] [Indexed: 12/12/2022] Open
Abstract
Objectives Thrombocytopenia is a frequent problem in neonatal sepsis and is among the most predictive, independent risk factors for sepsis-associated mortality. This study aims to clarify the occurrence, severity and duration of thrombocytopenia in neonatal sepsis. Study design A cohort study was carried out among all neonates with proven culture positive sepsis that were admitted to a tertiary NICU between 2006 and 2015 (n = 460). The occurrence, severity and duration of thrombocytopenia were recorded, as well as major bleedings and potential risk factors for mortality in neonatal sepsis. Results Sepsis was diagnosed in 460 of 6551 neonates (7%). Severe thrombocytopenia (platelets ≤50*109/L) occurred in 20% (92/460) of septic neonates. The median time for platelets to rise >100*109 was 6.0 days (interquartile range 4.0–7.0). On multivariate analysis, maternal hypertension, intravascular thrombosis and Gram negative (as opposed to Gram positive) sepsis were independently associated with thrombocytopenia in neonatal sepsis. In severe thrombocytopenia, 10% (9/92) suffered a severe IVH, compared to 5% (20/356) in neonates with platelets >50*109/L (p = 0.125). 10% (9/92) suffered a pulmonary hemorrhage, compared to 2% (9/368) in neonates with platelets >50*109/L (p = 0.001). On multivariate analysis, thrombocytopenia and Gram negative (as opposed to Gram positive) sepsis were independently associated with neonatal mortality. Conclusions Thrombocytopenia is independently associated with maternal hypertension, intravascular thrombosis and Gram negative sepsis. Thrombocytopenia in neonatal sepsis increases the risk of mortality nearly four-fold, with another six-fold increase in mortality in case of Gram negative sepsis.
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Affiliation(s)
- Isabelle M. C. Ree
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands
- * E-mail:
| | - Suzanne F. Fustolo-Gunnink
- Department of Pediatric Hematology, Academic Medical Center, Amsterdam, The Netherlands
- Sanquin Blood Supply, Department of Clinical Transfusion Research, Leiden, The Netherlands
| | - Vincent Bekker
- Division of Hematology/Immunology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands
| | - Karin J. Fijnvandraat
- Department of Pediatric Hematology, Academic Medical Center, Amsterdam, The Netherlands
- Sanquin Blood Supply, Department of Plasma Proteins, Amsterdam, the Netherlands
| | - Sylke J. Steggerda
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands
| | - Enrico Lopriore
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands
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Affiliation(s)
- R. Kapur
- Division of Hematology and Transfusion Medicine; Lund University; Lund Sweden
| | - J. W. Semple
- Division of Hematology and Transfusion Medicine; Lund University; Lund Sweden
- Keenan Research Centre for Biomedical Science; St. Michael's Hospital; Toronto ON Canada
- Departments of Pharmacology, Medicine and Laboratory Medicine and Pathobiology; University of Toronto; Toronto ON Canada
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Cetinkaya RA, Yilmaz S, Ünlü A, Petrone P, Marini C, Karabulut E, Urkan M, Kaya E, Karabacak K, Uyanik M, Eker I, Kilic A, Gunal A. The efficacy of platelet-rich plasma gel in MRSA-related surgical wound infection treatment: an experimental study in an animal model. Eur J Trauma Emerg Surg 2017; 44:859-867. [DOI: 10.1007/s00068-017-0852-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/25/2017] [Indexed: 11/28/2022]
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154
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Bacterial signatures in thrombus aspirates of patients with lower limb arterial and venous thrombosis. J Vasc Surg 2017; 67:1902-1907. [PMID: 28847664 DOI: 10.1016/j.jvs.2017.05.090] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/01/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Increasing data supports the role of bacterial inflammation in adverse events of cardiovascular and cerebrovascular diseases. In our previous research, DNA of bacterial species found in coronary artery thrombus aspirates and ruptured cerebral aneurysms were mostly of endodontic and periodontal origin, where Streptococcus mitis group DNA was the most common. We hypothesized that the genomes of S mitis group could be identified in thrombus aspirates of patients with lower limb arterial and deep venous thrombosis. METHODS Thrombus aspirates and control blood samples taken from 42 patients with acute or acute-on-chronic lower limb ischemia (Rutherford I-IIb) owing to arterial or graft thrombosis (n = 31) or lower limb deep venous thrombosis (n = 11) were examined using a quantitative real-time polymerase chain reaction to detect all possible bacterial DNA and DNA of S mitis group in particular. The samples were considered positive, if the amount of bacterial DNA in the thrombus aspirates was 2-fold or greater in comparison with control blood samples. RESULTS In the positive samples the mean difference for the total bacterial DNA was 12.1-fold (median, 7.1), whereas the differences for S mitis group DNA were a mean of 29.1 and a median of 5.2-fold. Of the arterial thrombus aspirates, 57.9% were positive for bacterial DNA, whereas bacterial genomes were found in 75% of bypass graft thrombosis with 77.8% of the prosthetic grafts being positive. Of the deep vein thrombus aspirates, 45.5% contained bacterial genomes. Most (80%) of bacterial DNA-positive cases contained DNA from the S mitis group. Previous arterial interventions were significantly associated with the occurrence of S mitis group DNA (P = .049, Fisher's exact test). CONCLUSIONS This is the first study to report the presence of bacterial DNA, predominantly of S mitis group origin, in the thrombus aspirates of surgical patients with lower limb arterial and deep venous thrombosis, suggesting their possible role in the pathogenesis of thrombotic events. Additional studies will, however, be needed to reach a final conclusion.
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155
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Acetylsalicylic acid differentially limits the activation and expression of cell death markers in human platelets exposed to Staphylococcus aureus strains. Sci Rep 2017; 7:5610. [PMID: 28717145 PMCID: PMC5514152 DOI: 10.1038/s41598-017-06024-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 06/07/2017] [Indexed: 12/14/2022] Open
Abstract
Beyond their hemostatic functions, platelets alter their inflammatory response according to the bacterial stimulus. Staphylococcus aureus is associated with exacerbated inflammation and thrombocytopenia, which is associated with poor prognosis during sepsis. Acetylsalicylic acid and statins prevent platelet aggregation and decrease the mortality rate during sepsis. Therefore, we assessed whether these two molecules could reduce in vitro platelet activation and the inflammatory response to S. aureus. Platelets were exposed to clinical strains of S. aureus in the presence or absence of acetylsalicylic acid or fluvastatin. Platelet activation, aggregation, and release of soluble sCD62P, sCD40 Ligand, RANTES and GROα were assessed. Platelet cell death was evaluated by analyzing the mitochondrial membrane potential, phosphatidylserine exposure, platelet microparticle release and caspase-3 activation. All S. aureus strains induced platelet activation but not aggregation and decreased the platelet count, the expression of cell death markers and the release of RANTES and GROα. Acetylsalicylic acid but not fluvastatin limited platelet activation and inflammatory factor release and restored the platelet count by protecting platelets from Staphylococcus-induced expression of cell death markers. This study demonstrates that acetylsalicylic acid limits S. aureus-induced effects on platelets by reducing cell death, revealing new strategies to reduce the platelet contribution to bacteremia-associated inflammation.
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156
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Faggio C, Sureda A, Morabito S, Sanches-Silva A, Mocan A, Nabavi SF, Nabavi SM. Flavonoids and platelet aggregation: A brief review. Eur J Pharmacol 2017; 807:91-101. [DOI: 10.1016/j.ejphar.2017.04.009] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 04/04/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022]
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157
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Introduction to a series of reviews on clinical platelet disorders. Blood 2017; 129:2821-2822. [PMID: 28416504 DOI: 10.1182/blood-2017-04-773507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 04/17/2017] [Indexed: 12/24/2022] Open
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Minasyan H. Sepsis and septic shock: Pathogenesis and treatment perspectives. J Crit Care 2017; 40:229-242. [PMID: 28448952 DOI: 10.1016/j.jcrc.2017.04.015] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/06/2017] [Accepted: 04/08/2017] [Indexed: 12/12/2022]
Abstract
The majority of bacteremias do not develop to sepsis: bacteria are cleared from the bloodstream. Oxygen released from erythrocytes and humoral immunity kill bacteria in the bloodstream. Sepsis develops if bacteria are resistant to oxidation and proliferate in erythrocytes. Bacteria provoke oxygen release from erythrocytes to arterial blood. Abundant release of oxygen to the plasma triggers a cascade of events that cause: 1. oxygen delivery failure to cells; 2. oxidation of plasma components that impairs humoral regulation and inactivates immune complexes; 3. disseminated intravascular coagulation and multiple organs' failure. Bacterial reservoir inside erythrocytes provides the long-term survival of bacteria and is the cause of ineffectiveness of antibiotics and host immune reactions. Treatment perspectives that include different aspects of sepsis development are discussed.
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159
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Hyslop SR, Josefsson EC. Undercover Agents: Targeting Tumours with Modified Platelets. Trends Cancer 2017; 3:235-246. [PMID: 28718434 DOI: 10.1016/j.trecan.2017.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 02/03/2023]
Abstract
Platelets have long been recognised to colocalise with tumour cells throughout haematogenous metastasis. Interactions between these cells contribute to tumour cell survival and motility through the vasculature into other tissues. Now, the research focus is shifting towards developing means to exploit this relationship to provide accurate diagnostics and therapies. Alterations to platelet count, RNA profile, and platelet ultrastructure are associated with the presence of certain malignancies, and may be used for cancer detection. Additionally, nanoparticle-based drug delivery systems are enhanced through the use of platelet membranes to specifically target cancer cells and camouflage the foreign particles from the immune system. This review discusses the development of platelets into highly powerful tools for cancer diagnostics and therapies.
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Affiliation(s)
- Stephanie R Hyslop
- Cancer & Haematology Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville VIC 3052, Australia; Department of Medical Biology, University of Melbourne 1G Royal Parade VIC 3052, Australia
| | - Emma C Josefsson
- Cancer & Haematology Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville VIC 3052, Australia; Department of Medical Biology, University of Melbourne 1G Royal Parade VIC 3052, Australia.
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160
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Tsai CS, Huang CY, Chen CH, Lin YW, Shih CM, Tsao NW, Chiang KH, Lee CY, Jeng H, Lin FY. Eotaxin-2 increased toll-like receptor 4 expression in endothelial cells in vitro and exacerbates high-cholesterol diet-induced atherogenesis in vivo. Am J Transl Res 2016; 8:5338-5353. [PMID: 28078007 PMCID: PMC5209487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 11/05/2016] [Indexed: 06/06/2023]
Abstract
Eotaxin-2 is a potent chemoattractant. High concentration of eotaxin-2 triggers the inflammation and tumor metastasis. Inhibition of eotaxin-2 may protect experimental atherogenesis although the mechanism is still unclear. Toll-like receptor 4 (TLR4) plays a major role mediating vascular inflammation, which is related to atherogenesis. In the results, we demonstrated that eotaxin-2 potentially impairs the tube formation capacity of human coronary artery endothelial cells (HCAECs). Eotaxin-2 augments the monocytic adhesion in lipopolysaccharides (LPS)-induced HCAECs, and which were reversed by TLR4 siRNA. Thus this study was conducted to investigate whether eotaxin-2 increases TLR4 expression, and then enhances the sensitivity of cells to antigen stimulation in HCAECs, which mediates the increasing of the development of serious atherosclerosis. In fact, we showed that JNK/SAPK, p38 MAPK, and ERK1/2 activation contribute to the transcriptional signaling pathway, JNK/SAPK and p38 MAPK regulate post-transcriptional modification, as well as protein-trafficking pathway in eotaxin-2-treated HCAECs TLR4 expression. RNA binding proteins, such as human antigen R (HuR) and tristetraprolin (TTP) mediate stability of TLR4 mRNA and chaperone, such as PRAT4A (a protein associated with TLR4) regulate trafficking of TLR4 protein might confer eotaxin-2 responsiveness. Eotaxin-2 administration led to a significant elevation of high cholesterol diet-induced atherosclerosis, and of TLR4 expression in B6.129S7-Ldlrtm1Her /J but not Ldlr-/--/-/Tlr4-/- mice. Our results revealed that eotaxin-2 induced overexpression TLR4 via mitogen-activated protein kinases (MAPK) signaling pathways, RNA binding proteins-mediated mRNA stabilization, and PRAT4A-regulated trafficking in HCAECs. These effects may lead to amplification of inflammatory responses contribute to the pathogenesis of cardiovascular disorders.
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Affiliation(s)
- Chien-Sung Tsai
- Division of Cardiovascular Surgery, Department of Surgery, Taoyuan Armed Forces General HospitalTaoyuan, Taiwan
- Division of Cardiovascular Surgery, Department of Surgery, Tri-Service General HospitalTaipei, Taiwan
- Department and Graduate Institute of Pharmacology, National Defense Medical CenterTaipei, Taiwan
| | - Chun-Yao Huang
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Department of Internal Medicine, Taipei Medical University HospitalTaipei, Taiwan
| | - Chien-Ho Chen
- School of Medical Laboratory Science and Biotechnology Taipei Medical UniversityTaipei, Taiwan
| | - Yi-Wen Lin
- Division of Cardiovascular Surgery, Department of Surgery, Tri-Service General HospitalTaipei, Taiwan
- Institute of Oral Biology, National Yang-Ming UniversityTaipei, Taiwan
| | - Chun-Ming Shih
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Department of Internal Medicine, Taipei Medical University HospitalTaipei, Taiwan
| | - Nai-Wen Tsao
- Division of Cardiovascular Surgery, Taipei Medical University HospitalTaipei, Taiwan
| | - Kuang-Hsing Chiang
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Department of Internal Medicine, Taipei Medical University HospitalTaipei, Taiwan
| | - Chi-Yuan Lee
- Graduate Institute of Clinical Medical Sciences, China Medical UniversityTaichung, Taiwan
| | - Hellen Jeng
- Division of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
| | - Feng-Yen Lin
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Department of Internal Medicine, Taipei Medical University HospitalTaipei, Taiwan
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Abstract
Antimicrobial peptides (AMPs), also known as host defense peptides, are small naturally occurring microbicidal molecules produced by the host innate immune response that function as a first line of defense to kill pathogenic microorganisms by inducing deleterious cell membrane damage. AMPs also possess signaling and chemoattractant activities and can modulate the innate immune response to enhance protective immunity or suppress inflammation. Human pathogens have evolved defense molecules and strategies to counter and survive the AMPs released by host immune cells such as neutrophils and macrophages. Here, we review the various mechanisms used by human bacterial pathogens to resist AMP-mediated killing, including surface charge modification, active efflux, alteration of membrane fluidity, inactivation by proteolytic digestion, and entrapment by surface proteins and polysaccharides. Enhanced understanding of AMP resistance at the molecular level may offer insight into the mechanisms of bacterial pathogenesis and augment the discovery of novel therapeutic targets and drug design for the treatment of recalcitrant multidrug-resistant bacterial infections.
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162
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Banskota S, Yousefpour P, Chilkoti A. Cell-Based Biohybrid Drug Delivery Systems: The Best of the Synthetic and Natural Worlds. Macromol Biosci 2016; 17. [DOI: 10.1002/mabi.201600361] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/18/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Samagya Banskota
- Department of Biomedical Engineering; Duke University; Durham NC 27708 USA
| | - Parisa Yousefpour
- Department of Biomedical Engineering; Duke University; Durham NC 27708 USA
| | - Ashutosh Chilkoti
- Department of Biomedical Engineering; Duke University; Durham NC 27708 USA
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Kucheryavykh LY, Dávila-Rodríguez J, Rivera-Aponte DE, Zueva LV, Washington AV, Sanabria P, Inyushin MY. Platelets are responsible for the accumulation of β-amyloid in blood clots inside and around blood vessels in mouse brain after thrombosis. Brain Res Bull 2016; 128:98-105. [PMID: 27908798 DOI: 10.1016/j.brainresbull.2016.11.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Platelets contain beta-amyloid precursor protein (APP) as well as Aβ peptide (Aβ) that can be released upon activation. During thrombosis, platelets are concentrated in clots and activated. METHODS We used in vivo fluorescent analysis and electron microscopy in mice to determine to what degree platelets are concentrated in clots. We used immunostaining to visualize Aβ after photothrombosis in mouse brains. RESULTS Both in vivo results and electron microscopy revealed that platelets were 300-500 times more concentrated in clots than in non-clotted blood. After thrombosis in control mice, but not in thrombocytopenic animals, Aβ immunofluorescence was present inside blood vessels in the visual cortex and around capillaries in the entorhinal cortex. CONCLUSION The increased concentration of platelets allows enhanced release of Aβ during thrombosis, suggesting an additional source of Aβ in the brains of Alzheimer's patients that may arise if frequent micro-thrombosis events occur in their brains.
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Affiliation(s)
- Lilia Y Kucheryavykh
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - Josué Dávila-Rodríguez
- School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - David E Rivera-Aponte
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - Lidia V Zueva
- Department of Physics, University of Puerto Rico Rio Piedras, San Juan, PR 00936, USA.
| | - A Valance Washington
- Department of Anatomy, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA; The Department of Biology, University of Puerto Rico Rio Piedras, San Juan, PR 00936, USA.
| | - Priscilla Sanabria
- Department of Physiology, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - Mikhail Y Inyushin
- Department of Physiology, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
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164
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Abstract
Publisher's Note: This article has a companion Point by Brass et al. Publisher's Note: Join in the discussion of these articles at Blood Advances Community Conversations.
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165
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Li RHL, Chan DL. Evaluation of platelet function using multiple electrode platelet aggregometry in dogs with septic peritonitis. J Vet Emerg Crit Care (San Antonio) 2016; 26:630-8. [PMID: 27428542 DOI: 10.1111/vec.12508] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 11/18/2015] [Accepted: 12/05/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To assess platelet function via multiple electrode platelet aggregometry (MEPA) in dogs with septic peritonitis and in healthy dogs. The secondary aim was to determine if there is prognostic significance to changes in platelet function observed in septic dogs. DESIGN Prospective, observational cohort study conducted from January 2012 to March 2014. SETTING University teaching hospital. ANIMALS Twenty dogs with septic peritonitis and 23 healthy dogs. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS MEPA using arachidonic acid, adenosine diphosphate, and collagen (COL) as agonists was measured within 24 hours of diagnosis of sepsis. Compared to healthy dogs, platelet aggregation was reduced in dogs with septic peritonitis for all agonists (P < 0.01). Overall mortality rate was 40%. MEPA in response to COL was significantly reduced in nonsurvivors compared to survivors (P = 0.019). Using receiver-operating characteristic curve statistics, a COL-activated MEPA less than 43.5 aggregation units had a sensitivity and specificity of 85.7% and 90.9%, respectively, for predicting nonsurvival in dogs with septic peritonitis. CONCLUSIONS Circulating platelets from dogs with septic peritonitis have diminished aggregation in response to multiple platelet agonists. MEPA may serve as an assessment tool for illness severity in this patient population.
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Affiliation(s)
- Ronald H L Li
- Section of Emergency and Critical Care, Department of Clinical Science and Services, Royal Veterinary College, University of London, London, UK. .,Dr. Li's current address: Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, UC Davis, Davis, CA.
| | - Daniel L Chan
- Section of Emergency and Critical Care, Department of Clinical Science and Services, Royal Veterinary College, University of London, London, UK
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de Stoppelaar SF, Claushuis TAM, Schaap MCL, Hou B, van der Poll T, Nieuwland R, van ‘t Veer C. Toll-Like Receptor Signalling Is Not Involved in Platelet Response to Streptococcus pneumoniae In Vitro or In Vivo. PLoS One 2016; 11:e0156977. [PMID: 27253707 PMCID: PMC4890788 DOI: 10.1371/journal.pone.0156977] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/23/2016] [Indexed: 12/20/2022] Open
Abstract
Streptococcus (S.) pneumoniae strains vary considerably in their ability to cause invasive disease in humans, which is at least in part determined by the capsular serotype. Platelets have been implicated as sentinel cells in the circulation for host defence. One of their utensils for this function is the expression of Toll-like receptors (TLRs). We here aimed to investigate platelet response to S. pneumoniae and a role for TLRs herein. Platelets were stimulated using four serotypes of S. pneumonia including an unencapsulated mutant strain. In vitro aggregation and flow cytometry assays were performed using blood of healthy volunteers, or blood of TLR knock out and WT mice. For in vivo pneumonia experiments, platelet specific Myd88 knockout (Plt-Myd88-/-) mice were used. We found that platelet aggregation was induced by unencapsulated S. pneumoniae only. Whole blood incubation with all S. pneumoniae serotypes tested resulted in platelet degranulation and platelet-leukocyte complex formation. Platelet activation was TLR independent, as responses were not inhibited by TLR blocking antibodies, not induced by TLR agonists and were equally induced in wild-type and Tlr2-/-, Tlr4-/-, Tlr2/4-/-, Tlr9-/- and Myd88-/- blood. Plt-Myd88-/- and control mice displayed no differences in bacterial clearance or immune response to pneumonia by unencapsulated S. pneumoniae. In conclusion, S. pneumoniae activates platelets through a TLR-independent mechanism that is impeded by the bacterial capsule. Additionally, platelet MyD88-dependent TLR signalling is not involved in host defence to unencapsulated S. pneumoniae in vivo.
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Affiliation(s)
- Sacha F. de Stoppelaar
- Center for Infection and Immunity Amsterdam (CINIMA), University of Amsterdam, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), University of Amsterdam, Amsterdam, the Netherlands
- * E-mail:
| | - Theodora A. M. Claushuis
- Center for Infection and Immunity Amsterdam (CINIMA), University of Amsterdam, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), University of Amsterdam, Amsterdam, the Netherlands
| | - Marianne C. L. Schaap
- Laboratory for Experimental and Clinical Chemistry (LEKC), University of Amsterdam, Amsterdam, the Netherlands
| | - Baidong Hou
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chaoyang District, Beijing, China
| | - Tom van der Poll
- Center for Infection and Immunity Amsterdam (CINIMA), University of Amsterdam, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), University of Amsterdam, Amsterdam, the Netherlands
- Division of Infectious Diseases, University of Amsterdam, Amsterdam, the Netherlands
| | - Rienk Nieuwland
- Laboratory for Experimental and Clinical Chemistry (LEKC), University of Amsterdam, Amsterdam, the Netherlands
| | - Cornelis van ‘t Veer
- Center for Infection and Immunity Amsterdam (CINIMA), University of Amsterdam, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), University of Amsterdam, Amsterdam, the Netherlands
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167
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Ko YP, Flick MJ. Fibrinogen Is at the Interface of Host Defense and Pathogen Virulence in Staphylococcus aureus Infection. Semin Thromb Hemost 2016; 42:408-21. [PMID: 27056151 PMCID: PMC5514417 DOI: 10.1055/s-0036-1579635] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fibrinogen not only plays a pivotal role in hemostasis but also serves key roles in antimicrobial host defense. As a rapidly assembled provisional matrix protein, fibrin(ogen) can function as an early line of host protection by limiting bacterial growth, suppressing dissemination of microbes to distant sites, and mediating host bacterial killing. Fibrinogen-mediated host antimicrobial activity occurs predominantly through two general mechanisms, namely, fibrin matrices functioning as a protective barrier and fibrin(ogen) directly or indirectly driving host protective immune function. The potential of fibrin to limit bacterial infection and disease has been countered by numerous bacterial species evolving and maintaining virulence factors that engage hemostatic system components within vertebrate hosts. Bacterial factors have been isolated that simply bind fibrinogen or fibrin, promote fibrin polymer formation, or promote fibrin dissolution. Staphylococcus aureus is an opportunistic gram-positive bacterium, the causative agent of a wide range of human infectious diseases, and a prime example of a pathogen exquisitely sensitive to host fibrinogen. Indeed, current data suggest fibrinogen serves as a context-dependent determinant of host defense or pathogen virulence in Staphylococcus infection whose ultimate contribution is dictated by the expression of S. aureus virulence factors, the path of infection, and the tissue microenvironment.
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Affiliation(s)
- Ya-Ping Ko
- Center for Infectious and Inflammatory Diseases, Institute for Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas
| | - Matthew J. Flick
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
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168
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Abstract
Platelets are megakaryocyte-derived cellular fragments, which lack a nucleus and are the smallest circulating cells and are classically known to have a major role in supporting hemostasis. Apart from this well-established role, it is now becoming evident that platelets are also capable of conveying other important functions, such as during infection and inflammation. This paper will outline these nonhemostatic functions in two major sections termed "Platelets versus pathogens" and "Platelet-target cell communication". Platelets actively contribute to protection against invading pathogens and are capable of regulating immune functions in various target cells, all through sophisticated and efficient mechanisms. These relatively novel features will be highlighted, illustrating the multifunctional role of platelets in inflammation.
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Affiliation(s)
- Rick Kapur
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael׳s Hospital, Canadian Blood Services, Toronto, Ontario, Canada
| | - John W Semple
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael׳s Hospital, Canadian Blood Services, Toronto, Ontario, Canada; Departments of Pharmacology, Medicine, and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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169
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Powers ME, Becker REN, Sailer A, Turner JR, Bubeck Wardenburg J. Synergistic Action of Staphylococcus aureus α-Toxin on Platelets and Myeloid Lineage Cells Contributes to Lethal Sepsis. Cell Host Microbe 2016; 17:775-87. [PMID: 26067604 DOI: 10.1016/j.chom.2015.05.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/15/2015] [Accepted: 05/22/2015] [Indexed: 02/06/2023]
Abstract
Multi-organ failure contributes to mortality in bacterial sepsis. Platelet and immune cell activation contribute to organ injury during sepsis, but the mechanisms by which bacterial virulence factors initiate these responses remain poorly defined. We demonstrate that during lethal sepsis, Staphylococcus aureus α-toxin simultaneously alters platelet activation and promotes neutrophil inflammatory signaling through interactions with its cellular receptor ADAM10. Platelet intoxication prevents endothelial barrier repair and facilitates formation of injurious platelet-neutrophil aggregates, contributing to lung and liver injury that is mitigated by ADAM10 deletion on platelets and myeloid lineage cells. While platelet- or myeloid-specific ADAM10 knockout does not alter sepsis mortality, double-knockout animals are highly protected. These results define a pathway by which a single bacterial toxin utilizes a widely expressed receptor to coordinate progressive, multi-organ disease in lethal sepsis. As an expression-enhancing ADAM10 polymorphism confers susceptibility to severe human sepsis, these studies highlight the importance of understanding molecular host-microbe interactions.
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Affiliation(s)
- Michael E Powers
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA
| | - Russell E N Becker
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA
| | - Anne Sailer
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Jerrold R Turner
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Juliane Bubeck Wardenburg
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA; Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA.
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170
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Wiewel MA, de Stoppelaar SF, van Vught LA, Frencken JF, Hoogendijk AJ, Klein Klouwenberg PMC, Horn J, Bonten MJ, Zwinderman AH, Cremer OL, Schultz MJ, van der Poll T. Chronic antiplatelet therapy is not associated with alterations in the presentation, outcome, or host response biomarkers during sepsis: a propensity-matched analysis. Intensive Care Med 2016; 42:352-360. [PMID: 26768440 PMCID: PMC4747987 DOI: 10.1007/s00134-015-4171-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/29/2015] [Indexed: 11/26/2022]
Abstract
Purpose Sepsis is a major health burden worldwide. Preclinical investigations in animals and retrospective studies in patients have suggested that inhibition of platelets may improve the outcome of sepsis. In this study we investigated whether chronic antiplatelet therapy impacts on the presentation and outcome of sepsis, and the host response. Methods We performed a prospective observational study in 972 patients admitted with sepsis to the mixed intensive care units (ICUs) of two hospitals in the Netherlands between January 2011 and July 2013. Of them, 267 patients (27.5 %) were on antiplatelet therapy (95.9 % acetylsalicylic acid) before admission. To account for differential likelihoods of receiving antiplatelet therapy, a propensity score was constructed, including variables associated with use of antiplatelet therapy. Cox proportional hazards regression was used to estimate the association of antiplatelet therapy with mortality. Results Antiplatelet therapy was not associated with sepsis severity at presentation, the primary source of infection, causative pathogens, the development of organ failure or shock during ICU stay, or mortality up to 90 days after admission, in either unmatched or propensity-matched analyses. Antiplatelet therapy did not modify the values of 19 biomarkers providing insight into hallmark host responses to sepsis, including activation of the coagulation system, the vascular endothelium, the cytokine network, and renal function, during the first 4 days after ICU admission. Conclusions Pre-existing antiplatelet therapy is not associated with alterations in the presentation or outcome of sepsis, or the host response. Electronic supplementary material The online version of this article (doi:10.1007/s00134-015-4171-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maryse A Wiewel
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Room G2-130, 1105 AZ, Amsterdam, The Netherlands.
- The Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | - Sacha F de Stoppelaar
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Room G2-130, 1105 AZ, Amsterdam, The Netherlands
- The Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lonneke A van Vught
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Room G2-130, 1105 AZ, Amsterdam, The Netherlands
- The Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jos F Frencken
- Department of Intensive Care Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Arie J Hoogendijk
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Room G2-130, 1105 AZ, Amsterdam, The Netherlands
- The Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter M C Klein Klouwenberg
- Department of Intensive Care Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Janneke Horn
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Marc J Bonten
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Aeilko H Zwinderman
- Department of Clinical Epidemiology, Bioinformatics, and Biostatistics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Olaf L Cremer
- Department of Intensive Care Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcus J Schultz
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Tom van der Poll
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Room G2-130, 1105 AZ, Amsterdam, The Netherlands
- The Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Division of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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171
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Wentz JM, Vainstein V, Oldson D, Gluzman-Poltorak Z, Basile LA, Stricklin D. Mathematical model of radiation effects on thrombopoiesis in rhesus macaques and humans. J Theor Biol 2015; 383:44-60. [PMID: 26232694 DOI: 10.1016/j.jtbi.2015.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 07/01/2015] [Accepted: 07/16/2015] [Indexed: 12/20/2022]
Abstract
A mathematical model that describes the effects of acute radiation exposure on thrombopoiesis in primates and humans is presented. Thrombopoiesis is a complex multistage dynamic process with potential differences between species. Due to known differences in cellular radiosensitivities, nadir times, and cytopenia durations, direct extrapolation from rhesus to human platelet dynamics is unrealistic. Developing mathematical models of thrombopoiesis for both humans and primates allows for the comparison of the system's response across species. Thus, data obtained in primate experiments can be extrapolated to predictions in humans. Parameter values for rhesus macaques and humans were obtained either from direct experimental measurements or through optimization procedures using dynamic data on platelet counts following radiation exposure. Model simulations accurately predict trends observed in platelet dynamics: at low radiation doses platelet counts decline after a time lag, and nadir depth is dose dependent. The models were validated using data that was not used during the parameterization process. In particular, additional experimental data was used for rhesus, and accident and platelet donor data was used for humans. The model aims to simulate the average response in rhesus and humans following irradiation. Variation in platelet dynamics due to individual variability can be modeled using Monte Carlo simulations in which parameter values are sampled from distributions. This model provides insight into the time course of the physiological effects of radiation exposure, information which could be valuable for disaster planning and survivability analysis and help in drug development of radiation medical countermeasures.
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Affiliation(s)
- J M Wentz
- Applied Research Associates, Inc., Arlington, VA, United States.
| | - V Vainstein
- Neumedicines, Inc., Pasadena, CA, United States
| | - D Oldson
- Applied Research Associates, Inc., Arlington, VA, United States
| | | | - L A Basile
- Neumedicines, Inc., Pasadena, CA, United States
| | - D Stricklin
- Applied Research Associates, Inc., Arlington, VA, United States
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172
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Hu CMJ, Fang RH, Wang KC, Luk BT, Thamphiwatana S, Dehaini D, Nguyen P, Angsantikul P, Wen CH, Kroll AV, Carpenter C, Ramesh M, Qu V, Patel SH, Zhu J, Shi W, Hofman FM, Chen TC, Gao W, Zhang K, Chien S, Zhang L. Nanoparticle biointerfacing by platelet membrane cloaking. Nature 2015; 526:118-21. [PMID: 26374997 PMCID: PMC4871317 DOI: 10.1038/nature15373] [Citation(s) in RCA: 1136] [Impact Index Per Article: 126.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 08/12/2015] [Indexed: 12/15/2022]
Abstract
Development of functional nanoparticles can be encumbered by unanticipated material properties and biological events, which can affect nanoparticle effectiveness in complex, physiologically relevant systems. Despite the advances in bottom-up nanoengineering and surface chemistry, reductionist functionalization approaches remain inadequate in replicating the complex interfaces present in nature and cannot avoid exposure of foreign materials. Here we report on the preparation of polymeric nanoparticles enclosed in the plasma membrane of human platelets, which are a unique population of cellular fragments that adhere to a variety of disease-relevant substrates. The resulting nanoparticles possess a right-side-out unilamellar membrane coating functionalized with immunomodulatory and adhesion antigens associated with platelets. Compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and lack particle-induced complement activation in autologous human plasma. The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery.
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Affiliation(s)
- Che-Ming J Hu
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Ronnie H Fang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Kuei-Chun Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Brian T Luk
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA.,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Soracha Thamphiwatana
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Diana Dehaini
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Phu Nguyen
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Pavimol Angsantikul
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Cindy H Wen
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - Ashley V Kroll
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Cody Carpenter
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Manikantan Ramesh
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Vivian Qu
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Sherrina H Patel
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - Jie Zhu
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - William Shi
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - Florence M Hofman
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Thomas C Chen
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Weiwei Gao
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Kang Zhang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA.,Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA.,Veterans Administration Healthcare System, San Diego, California 92093, USA
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Liangfang Zhang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
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173
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Kapur R, Zufferey A, Boilard E, Semple JW. Nouvelle cuisine: platelets served with inflammation. THE JOURNAL OF IMMUNOLOGY 2015; 194:5579-87. [PMID: 26048965 DOI: 10.4049/jimmunol.1500259] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Platelets are small cellular fragments with the primary physiological role of maintaining hemostasis. In addition to this well-described classical function, it is becoming increasingly clear that platelets have an intimate connection with infection and inflammation. This stems from several platelet characteristics, including their ability to bind infectious agents and secrete many immunomodulatory cytokines and chemokines, as well as their expression of receptors for various immune effector and regulatory functions, such as TLRs, which allow them to sense pathogen-associated molecular patterns. Furthermore, platelets contain RNA that can be nascently translated under different environmental stresses, and they are able to release membrane microparticles that can transport inflammatory cargo to inflammatory cells. Interestingly, acute infections can also result in platelet breakdown and thrombocytopenia. This report highlights these relatively new aspects of platelets and, thus, their nonhemostatic nature in an inflammatory setting.
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Affiliation(s)
- Rick Kapur
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Canadian Blood Services, Toronto, Ontario M5B 1W8, Canada
| | - Anne Zufferey
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - Eric Boilard
- Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l'Université Laval, Quebec City, Quebec G1V 4G2, Canada
| | - John W Semple
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Canadian Blood Services, Toronto, Ontario M5B 1W8, Canada; Department of Pharmacology, University of Toronto, Toronto, Ontario M5B 1W8, Canada; Department of Medicine, University of Toronto, Toronto, Ontario M5B 1W8, Canada; and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5B 1W8, Canada
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174
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Mice expressing a mutant form of fibrinogen that cannot support fibrin formation exhibit compromised antimicrobial host defense. Blood 2015; 126:2047-58. [PMID: 26228483 DOI: 10.1182/blood-2015-04-639849] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/26/2015] [Indexed: 12/14/2022] Open
Abstract
Fibrin(ogen) is central to hemostasis and thrombosis and also contributes to multiple physiologic and pathologic processes beyond coagulation. However, the precise contribution of soluble fibrinogen vs insoluble fibrin matrices to vascular integrity, tissue repair, inflammation, and disease has been undefined and unapproachable. To establish the means to distinguish fibrinogen- and fibrin-dependent processes in vivo, Fib(AEK) mice were generated that carry normal levels of circulating fibrinogen but lack the capacity for fibrin polymer formation due to a germ-line mutation in the Aα chain thrombin cleavage site. Homozygous Fib(AEK) mice developed to term and exhibited postnatal survival superior to that of fibrinogen-deficient mice. Unlike fibrinogen-deficient mice, platelet-rich plasma from Fib(AEK) mice supported normal platelet aggregation in vitro, highlighting that fibrinogen(AEK) retains the functional capacity to support interactions with platelets. Thrombin failed to release fibrinopeptide-A from fibrinogen(AEK) and failed to induce polymer formation with Fib(AEK) plasma or purified fibrinogen(AEK) in 37°C mixtures regardless of incubation time. Fib(AEK) mice displayed both an absence of fibrin polymer formation following liver injury, as assessed by electron microscopy, and a failure to generate stable occlusive thrombi following FeCl3 injury of carotid arteries. Fib(AEK) mice exhibited a profound impediment in Staphylococcus aureus clearance following intraperitoneal infection similar to fibrinogen-deficient mice, yet Fib(AEK) mice displayed a significant infection dose-dependent survival advantage over fibrinogen-deficient mice following peritonitis challenge. Collectively, these findings establish for the first time that fibrin polymer is the molecular form critical for antimicrobial mechanisms while simultaneously highlighting biologically meaningful contributions and functions of the soluble molecule.
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175
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Mariani E, Canella V, Berlingeri A, Bielli A, Cattini L, Landini MP, Kon E, Marcacci M, Di Matteo B, Filardo G. Leukocyte presence does not increase microbicidal activity of Platelet-rich Plasma in vitro. BMC Microbiol 2015. [PMID: 26223356 PMCID: PMC4520275 DOI: 10.1186/s12866-015-0482-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Background Human platelets are a rich reservoir of molecules that promote regenerative processes and microbicidal activity. This activity might be increased by concentration in platelet-rich plasma (PRP) products and modulated by the presence of leukocytes. Despite extensive use in clinical procedures, only few studies have investigated PRP’s real microbicidal potential. Therefore, this study aimed at comparing the in vitro microbicidal activity of platelets and leukocyte-enriched PRP (L-PRP) to pure platelet-rich plasma (P-PRP) and the contribution of leukocytes to microbicidal properties. Antimicrobial effects of P- and L-PRP were tested against Escherichia Coli, Staphylococcus Aureus, Klebsiella Pneumoniae, Pseudomonas Aeruginosa and Enterococcus Faecalis. Furthermore, L-PRP was frozen (L-PRP cryo) to assess whether the preparation maintained in vitro characteristics. Microbicidal proteins released by the three preparations were also evaluated. Results L-PRP, L-PRP cryo and P-PRP generally induced comparable bacterial growth inhibition for up to 4 h’ incubation, range 1–4 log. MIP-1α, RANTES, GRO-α, IL-8, NAP-2, SDF-1α and IL-6 showed strong microbicidal potential. Conclusions We found in vitro antibacterial activity of L-PRP and P-PRP and the possibility to cryopreserve L-PRP, without important changes to its effectiveness; similar microbicidal activity between preparations containing or not leukocytes; and the contribution of three new molecules (NAP-2, SDF-1α and IL-6).
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Affiliation(s)
- Erminia Mariani
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136, Bologna, Italy. .,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy.
| | - Valentina Canella
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136, Bologna, Italy.
| | - Andrea Berlingeri
- Unit of Clinical Microbiology, St. Orsola University Hospital, University of Bologna, Bologna, Italy.
| | - Alessandra Bielli
- Unit of Clinical Microbiology, St. Orsola University Hospital, University of Bologna, Bologna, Italy.
| | - Luca Cattini
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136, Bologna, Italy.
| | - Maria Paola Landini
- Unit of Clinical Microbiology, St. Orsola University Hospital, University of Bologna, Bologna, Italy.
| | - Elizaveta Kon
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, Bologna, Italy.
| | - Maurilio Marcacci
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, Bologna, Italy.
| | - Berardo Di Matteo
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, Bologna, Italy.
| | - Giuseppe Filardo
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, Bologna, Italy.
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176
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van Sorge NM, Cole JN, Kuipers K, Henningham A, Aziz RK, Kasirer-Friede A, Lin L, Berends ETM, Davies MR, Dougan G, Zhang F, Dahesh S, Shaw L, Gin J, Cunningham M, Merriman JA, Hütter J, Lepenies B, Rooijakkers SHM, Malley R, Walker MJ, Shattil SJ, Schlievert PM, Choudhury B, Nizet V. The classical lancefield antigen of group a Streptococcus is a virulence determinant with implications for vaccine design. Cell Host Microbe 2015; 15:729-740. [PMID: 24922575 DOI: 10.1016/j.chom.2014.05.009] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 04/15/2014] [Accepted: 04/29/2014] [Indexed: 12/19/2022]
Abstract
Group A Streptococcus (GAS) is a leading cause of infection-related mortality in humans. All GAS serotypes express the Lancefield group A carbohydrate (GAC), comprising a polyrhamnose backbone with an immunodominant N-acetylglucosamine (GlcNAc) side chain, which is the basis of rapid diagnostic tests. No biological function has been attributed to this conserved antigen. Here we identify and characterize the GAC biosynthesis genes, gacA through gacL. An isogenic mutant of the glycosyltransferase gacI, which is defective for GlcNAc side-chain addition, is attenuated for virulence in two infection models, in association with increased sensitivity to neutrophil killing, platelet-derived antimicrobials in serum, and the cathelicidin antimicrobial peptide LL-37. Antibodies to GAC lacking the GlcNAc side chain and containing only polyrhamnose promoted opsonophagocytic killing of multiple GAS serotypes and protected against systemic GAS challenge after passive immunization. Thus, the Lancefield antigen plays a functional role in GAS pathogenesis, and a deeper understanding of this unique polysaccharide has implications for vaccine development.
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Affiliation(s)
- Nina M van Sorge
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA.,Medical Microbiology, University Medical Center Utrecht,3584 CX Utrecht, The Netherlands
| | - Jason N Cole
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA.,Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland,QLD 4072, Australia
| | - Kirsten Kuipers
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Anna Henningham
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Ramy K Aziz
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA.,Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University,11562 Cairo, Egypt
| | - Ana Kasirer-Friede
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Leo Lin
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Evelien T M Berends
- Medical Microbiology, University Medical Center Utrecht,3584 CX Utrecht, The Netherlands
| | - Mark R Davies
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland,QLD 4072, Australia.,The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton, CB10 1SA,United Kingdom
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton, CB10 1SA,United Kingdom
| | - Fan Zhang
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA 02115, USA
| | - Samira Dahesh
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Laura Shaw
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Jennifer Gin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Madeleine Cunningham
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Joseph A Merriman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Julia Hütter
- Max Planck Institute of Colloids and Interfaces, Department of Biomolecular Systems, 14476 Potsdam, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Department of Biology, Chemistry and Pharmacy, 14195 Berlin, Germany
| | - Bernd Lepenies
- Max Planck Institute of Colloids and Interfaces, Department of Biomolecular Systems, 14476 Potsdam, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Department of Biology, Chemistry and Pharmacy, 14195 Berlin, Germany
| | - Suzan H M Rooijakkers
- Medical Microbiology, University Medical Center Utrecht,3584 CX Utrecht, The Netherlands
| | - Richard Malley
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA 02115, USA
| | - Mark J Walker
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland,QLD 4072, Australia
| | - Sanford J Shattil
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Patrick M Schlievert
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Biswa Choudhury
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
| | - Victor Nizet
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA.,Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
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Reviakine I. New horizons in platelet research: Understanding and harnessing platelet functional diversity. Clin Hemorheol Microcirc 2015; 60:133-52. [DOI: 10.3233/ch-151942] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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178
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Platelets at the interface of thrombosis, inflammation, and cancer. Blood 2015; 126:582-8. [PMID: 26109205 DOI: 10.1182/blood-2014-08-531582] [Citation(s) in RCA: 392] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 06/18/2015] [Indexed: 12/13/2022] Open
Abstract
Although once primarily recognized for its roles in hemostasis and thrombosis, the platelet has been increasingly recognized as a multipurpose cell. Indeed, circulating platelets have the ability to influence a wide range of seemingly unrelated pathophysiologic events. Here, we highlight some of the notable observations that link platelets to inflammation, reinforcing the platelet's origin from a lower vertebrate cell type with both hemostatic and immunologic roles. In addition, we consider the relevance of platelets in cancer biology by focusing on the hallmarks of cancer and the ways platelets can influence multistep development of tumors. Beyond its traditional role in hemostasis and thrombosis, the platelet's involvement in the interplay between hemostasis, thrombosis, inflammation, and cancer is likely complex, yet extremely important in each disease process. The existence of animal models of platelet dysfunction and currently used antiplatelet therapies provide a framework for understanding mechanistic insights into a wide range of pathophysiologic events. Thus, the basic scientist studying platelet function can think beyond the traditional hemostasis and thrombosis paradigms, while the practicing hematologist must appreciate platelet relevance in a wide range of disease processes.
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Effective Treatment of Staphylococcal Scalded Skin Syndrome with Platelet Microbicidal Protein in CBRB-Rb(8.17)1Iem Mice Model. Probiotics Antimicrob Proteins 2015; 7:203-6. [PMID: 26044057 DOI: 10.1007/s12602-015-9194-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Skin and soft-tissue infections are among the most common infections. Staphylococcus aureus may cause a number of toxin-mediated diseases, including staphylococcal scalded skin syndrome (SSSS). The therapeutic efficacy of some antimicrobial peptides was recently evaluated in a mouse model of SSSS. This study is the first in vivo demonstration of the use of PMP to improve outcome of SSSS. Twenty-four CBRB-Rb(8.17)1Iem female mice naturally infected by endogenous S. aureus with SSSS symptoms were used in this work and divided into two equal groups. From neck of each mouse was isolated and identified endogenous exfoliative producing strain of S. aureus. PMP was obtained from human platelets and tested against Bacillus subtilis ATCC 6633. PMP had bactericidal activity against B. subtilis ATTC 6633 and endogenous strain of S. aureus at 2.0 ± 0.5 and 14.5 ± 0.5 µg/ml, respectively. At 4 weeks, the mice of experimental group were treated subcutaneous near exfoliative zone with 0.2 ml of PMP in final concentration 10 µg/ml every day. Control mice was injected with 0.2 ml 0.9% NaCl. At 1 day of experiment maximal zone of alopecia was at PMP-treating group (380 ± 20 mm(2)) in comparison with control group (167 ± 10 mm(2), p < 0.01). At 50 day of observation (22nd day after the end of treatment), the square of alopecia in control group was 1220 ± 40 mm(2) in comparison with 870 ± 17 mm(2) in experimental group (p < 0.01). The antistaphylococcal in vivo activity of PMP demonstrated in present study makes these molecules potentially useful for treatment of SSSS.
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Abstract
OBJECTIVES Streptococcus pneumoniae is the most common causative pathogen in community-acquired pneumonia. In patients, thrombocytopenia is correlated with an adverse outcome of pneumonia. Platelets can modulate the host response to infection in several ways, that is, by facilitating clot formation, production of antimicrobial proteins, and interaction with neutrophils. We studied the effect of thrombocytopenia during murine pneumococcal pneumonia. DESIGN Animal study. SETTING University research laboratory. SUBJECTS Mice. INTERVENTIONS Pneumonia was induced by intranasal inoculation of S. pneumoniae. Platelets were depleted by anti-mouse thrombocyte serum; controls received nonimmunogenic serum. In separate studies, mice were treated with the platelet P2Y12 receptor inhibitor clopidogrel or placebo. MEASUREMENTS AND MAIN RESULTS Thrombocytopenic mice (platelet counts < 1% of uninfected controls) showed a reduced survival during pneumococcal pneumonia (27% vs 75% among controls; p = 0.003), which was associated with higher bacterial loads in lungs, spleen, and blood. Thrombocytopenic mice showed enhanced coagulation activation (thrombin-antithrombin complexes) in plasma. Proinflammatory cytokine levels were higher in plasma but not in lungs of thrombocytopenic mice. Although clopidogrel treatment strongly prolonged the bleeding time, it did not impact on bacterial loads during pneumococcal pneumonia. CONCLUSIONS Platelets play a protective role during pneumococcal pneumonia independent of their aggregation.
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Mariani E, Filardo G, Canella V, Berlingeri A, Bielli A, Cattini L, Landini MP, Kon E, Marcacci M, Facchini A. Platelet-rich plasma affects bacterial growth in vitro. Cytotherapy 2015; 16:1294-304. [PMID: 25108654 DOI: 10.1016/j.jcyt.2014.06.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 05/30/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND AIMS Platelet-rich plasma (PRP), a blood derivative rich in platelets, is a relatively new technique used in tissue regeneration and engineering. The increased quantity of platelets makes this formulation of considerable value for their role in tissue healing and microbicidal activity. This activity was investigated against five of the most important strains involved in nosocomial infections (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and Streptococcus faecalis) to understand the prophylactic role of pure (P)-PRP. Microbicidal proteins released from activated P-PRP platelets were also determined. METHODS The microbicidal activity of P-PRP and platelet-poor plasma (PPP) was evaluated on different concentrations of the five bacterial strains incubated for 1, 2, 4 and 18 h and plated on agar for 18-24 h. P-PRP and PPP-released microbicidal proteins were evaluated by means of multiplex bead-based immunoassays. RESULTS P-PRP and PPP inhibited bacterial growth for up to 2 h of incubation. The effect of P-PRP was significantly higher than that of PPP, mainly at the low seeding concentrations and/or shorter incubation times, depending on the bacterial strain. Chemokine (C-C motif) ligand-3, chemokine (C-C motif) ligand-5 and chemokine (C-X-C motif) ligand-1 were the molecules mostly related to Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus faecalis inhibition. Escherichia coli and Klebsiella pneumoniae were less influenced. CONCLUSIONS The present results show that P-PRP might supply an early protection against bacterial contaminations during surgical interventions because the inhibitory activity is already evident from the first hour of treatment, which suggests that physiological molecules supplied in loco might be important in the time frame needed for the activation of the innate immune response.
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Affiliation(s)
- Erminia Mariani
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy.
| | - Giuseppe Filardo
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Valentina Canella
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Andrea Berlingeri
- Operative Unit of Clinical Microbiology, St. Orsola-Malpighi University Hospital, Regional Reference Centre for Microbiological Emergencies, Bologna, Italy
| | - Alessandra Bielli
- Operative Unit of Clinical Microbiology, St. Orsola-Malpighi University Hospital, Regional Reference Centre for Microbiological Emergencies, Bologna, Italy
| | - Luca Cattini
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Maria Paola Landini
- Operative Unit of Clinical Microbiology, St. Orsola-Malpighi University Hospital, Regional Reference Centre for Microbiological Emergencies, Bologna, Italy
| | - Elizaveta Kon
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Maurilio Marcacci
- Laboratory of Biomechanics and Technology Innovation/NABI, 2nd Orthopaedic and Traumatologic Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Andrea Facchini
- Laboratory of Immunorheumatology and Tissue Regeneration/RAMSES, Rizzoli Orthopaedic Institute, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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Ivanov IB, Gritsenko VA, Kuzmin MD. The Effect of Brief Exposure to Sub-Therapeutic Concentrations of Chlorhexidine Digluconate on the Susceptibility of Staphylococci to Platelet Microbicidal Protein. Surg Infect (Larchmt) 2015; 16:263-6. [PMID: 25830691 DOI: 10.1089/sur.2013.173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Antiseptic agents are widely used in hospitals and are essential when prevention and control of nosocomial infections is required. It is necessary to consider several aspects that affect the biocide activity because they have direct impact on the nosocomial infection rate. Organisms belonging to the Staphylococcus genus are involved in such infections and chlorhexidine digluconate (CHXD) is one of the most used antiseptic agents for human and animal health. In the context of such infections, anti-bacterial peptides have been isolated from platelets and have been termed platelet microbicidal proteins (PMP). Platelet microbicidal proteins have been shown to enhance the bacterial inhibitory activities of sub-therapeutic concentrations of antibiotics. The main objective of this study was to investigate the effect of brief exposure to different sub-therapeutic concentrations of CHXD on the susceptibility of staphylococci to PMP. METHODS The influence of brief exposure to three different sub-therapeutic concentrations of CHXD (0.005%, 0.0025%, and 0.00125%) on the subsequent staphylocidal effect of PMP was evaluated. RESULTS Among all clinical staphylococcal strains studied, all isolates were considered to be resistant to the bactericidal action of PMP. Exposure of staphylococci to CHXD prior to PMP resulted in significantly increased staphylococcal killing compared with the killing achieved with PMP alone. This enhanced effect was most marked for concentrations of CHXD of 0.005%. CONCLUSION The combined data indicate that PMP exerts cooperative bactericidal effect with CHXD. The anti-staphylococcal PMP and CHXD synergistic activity in vitro demonstrated in the present study make these molecules potentially useful for preventing endovascular catheter-associated infections. Future research based on animal and human models is needed to elucidate the in vivo efficacies and toxicities and utility in clinical practice.
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Affiliation(s)
- Iuri B Ivanov
- Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia
| | - Viktor A Gritsenko
- Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia
| | - Michael D Kuzmin
- Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia
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183
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McFadyen JD, Kaplan ZS. Platelets Are Not Just for Clots. Transfus Med Rev 2015; 29:110-9. [DOI: 10.1016/j.tmrv.2014.11.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 11/04/2014] [Accepted: 11/09/2014] [Indexed: 12/18/2022]
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184
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Nording HM, Seizer P, Langer HF. Platelets in inflammation and atherogenesis. Front Immunol 2015; 6:98. [PMID: 25798138 PMCID: PMC4351644 DOI: 10.3389/fimmu.2015.00098] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/19/2015] [Indexed: 12/12/2022] Open
Abstract
Platelets contribute to processes beyond thrombus formation and may play a so far underestimated role as an immune cell in various circumstances. This review outlines immune functions of platelets in host defense, but also how they may contribute to mechanisms of infectious diseases. A particular emphasis is placed on the interaction of platelets with other immune cells. Furthermore, this article outlines the features of atherosclerosis as an inflammatory vascular disease highlighting the role of platelet crosstalk with cellular and soluble factors involved in atheroprogression. Understanding, how platelets influence these processes of vascular remodeling will shed light on their role for tissue homeostasis beyond intravascular thrombosis. Finally, translational implications of platelet-mediated inflammation in atherosclerosis are discussed.
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Affiliation(s)
- Henry M. Nording
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
- Section for Cardioimmunology, Eberhard Karls-University Tübingen, Tübingen, Germany
| | - Peter Seizer
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
| | - Harald F. Langer
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
- Section for Cardioimmunology, Eberhard Karls-University Tübingen, Tübingen, Germany
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185
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Cognasse F, Nguyen KA, Damien P, McNicol A, Pozzetto B, Hamzeh-Cognasse H, Garraud O. The Inflammatory Role of Platelets via Their TLRs and Siglec Receptors. Front Immunol 2015; 6:83. [PMID: 25784910 PMCID: PMC4345914 DOI: 10.3389/fimmu.2015.00083] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/12/2015] [Indexed: 12/16/2022] Open
Abstract
Platelets are non-nucleated cells that play central roles in the processes of hemostasis, innate immunity, and inflammation; however, several reports show that these distinct functions are more closely linked than initially thought. Platelets express numerous receptors and contain hundreds of secretory products. These receptors and secretory products are instrumental to the platelet functional responses. The capacity of platelets to secrete copious amounts of cytokines, chemokines, and related molecules appears intimately related to the role of the platelet in inflammation. Platelets exhibit non-self-infectious danger detection molecules on their surfaces, including those belonging to the “toll-like receptor” family, as well as pathogen sensors of other natures (Ig- or complement receptors, etc.). These receptors permit platelets to both bind infectious agents and deliver differential signals leading to the secretion of cytokines/chemokines, under the control of specific intracellular regulatory pathways. In contrast, dysfunctional receptors or dysregulation of the intracellular pathway may increase the susceptibility to pathological inflammation. Physiological vs. pathological inflammation is tightly controlled by the sensors of danger expressed in resting, as well as in activated, platelets. These sensors, referred to as pathogen recognition receptors, primarily sense danger signals termed pathogen associated molecular patterns. As platelets are found in inflamed tissues and are involved in auto-immune disorders, it is possible that they can also be stimulated by internal pathogens. In such cases, platelets can also sense danger signals using damage associated molecular patterns (DAMPs). Some of the most significant DAMP family members are the alarmins, to which the Siglec family of molecules belongs. This review examines the role of platelets in anti-infection immunity via their TLRs and Siglec receptors.
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Affiliation(s)
- Fabrice Cognasse
- Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France ; GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | - Kim Anh Nguyen
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | - Pauline Damien
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | - Archibald McNicol
- Faculty of Health Sciences, Colleges of Pharmacy and Medicine, University of Manitoba , Winnipeg, MB , Canada
| | - Bruno Pozzetto
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | | | - Olivier Garraud
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France ; Institut National de Transfusion Sanguine (INTS) , Paris , France
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López C, Álvarez ME, Carmona JU. Effect of Equine Leukocyte-Reduced Platelet Concentrates on Methicillin-Resistant Staphylococcus aureus Cultures and Measurement of Temporal Growth Factor Degradation. J Equine Vet Sci 2015. [DOI: 10.1016/j.jevs.2015.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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188
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Hamzeh-Cognasse H, Damien P, Chabert A, Pozzetto B, Cognasse F, Garraud O. Platelets and infections - complex interactions with bacteria. Front Immunol 2015; 6:82. [PMID: 25767472 PMCID: PMC4341565 DOI: 10.3389/fimmu.2015.00082] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/11/2015] [Indexed: 12/29/2022] Open
Abstract
Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-like receptors but also integrins conventionally described in the hemostatic response, such as GPIIb–IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet-bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis, or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of neutrophil extracellular traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet–bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the aggregation response.
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Affiliation(s)
| | - Pauline Damien
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Adrien Chabert
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Bruno Pozzetto
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Fabrice Cognasse
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France ; Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France
| | - Olivier Garraud
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France ; Institut National de la Transfusion Sanguine , Paris , France
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189
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Garraud O, Cognasse F. Are Platelets Cells? And if Yes, are They Immune Cells? Front Immunol 2015; 6:70. [PMID: 25750642 PMCID: PMC4335469 DOI: 10.3389/fimmu.2015.00070] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 02/03/2015] [Indexed: 02/06/2023] Open
Abstract
Small fragments circulating in the blood were formally identified by the end of the nineteenth century, and it was suggested that they assisted coagulation via interactions with vessel endothelia. Wright, at the beginning of the twentieth century, identified their bone-marrow origin. For long, platelets have been considered sticky assistants of hemostasis and pollutants of blood or tissue samples; they were just cell fragments. As such, however, they were acknowledged as immunizing (to specific HPA and HLA markers): the platelet’s dark face. The enlightened face showed that besides hemostasis, platelets contained factors involved in healing. As early as 1930s, platelets entered the arsenal of medicines were transfused, and were soon manipulated to become a kind of glue to repair damaged tissues. Some gladly categorized platelets as cells but they were certainly not fully licensed as such for cell physiologists. Actually, platelets possess almost every characteristic of cells, apart from being capable of organizing their genes: they have neither a nucleus nor genes. This view prevailed until it became evident that platelets play a role in homeostasis and interact with cells other than with vascular endothelial cells; then began the era of physiological and also pathological inflammation. Platelets have now entered the field of immunity as inflammatory cells. Does assistance to immune cells itself suffice to license a cell as an “immune cell”? Platelets prove capable of sensing different types of signals and organizing an appropriate response. Many cells can do that. However, platelets can use a complete signalosome (apart from the last transcription step, though it is likely that this step can be circumvented by retrotranscribing RNA messages). The question has also arisen as to whether platelets can present antigen via their abundantly expressed MHC class I molecules. In combination, these properties argue in favor of allowing platelets the title of immune cells.
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Affiliation(s)
- Olivier Garraud
- Institut National de la Transfusion Sanguine , Paris , France ; EA3064, Université de Lyon , Saint-Etienne , France
| | - Fabrice Cognasse
- EA3064, Université de Lyon , Saint-Etienne , France ; Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France
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190
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Wuescher LM, Takashima A, Worth RG. A novel conditional platelet depletion mouse model reveals the importance of platelets in protection against Staphylococcus aureus bacteremia. J Thromb Haemost 2015; 13:303-13. [PMID: 25418277 PMCID: PMC4320667 DOI: 10.1111/jth.12795] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 11/16/2014] [Indexed: 12/29/2022]
Abstract
BACKGROUND Platelets are critical cells for maintaining vascular hemostasis, but their activities in other processes are becoming apparent. Specifically, the ability of platelets to recognize and respond to infectious agents is an important area of investigation. To understand the physiologic roles of platelets in vivo, most researchers have used antibody-mediated platelet depletion, which has certain limitations. OBJECTIVE To develop an optimal system with which to study the contribution of platelets to protection against S. aureus blood infection. METHODS Here, we describe a novel experimental model of conditional platelet depletion based on the Cre-recombinase cell ablation system. With this technology, the simian diphtheria toxin receptor was expressed in platelet factor 4-positive cells (megakaryocytes and platelets). RESULTS Systemic administration of diphtheria toxin every 48 h resulted in reduced platelet numbers that became undetectable after 6 days. Although platelets were depleted, no other blood cells were affected. With this newly developed model, the functional contributions of platelets to protection against Staphylococcus aureus bacteremia was examined. Platelet-depleted mice succumbed to infection more rapidly than wild-type mice, and had a significantly higher bacterial burden in kidneys, elevated levels of serum markers of kidney damage, and increased levels of cytokines indicative of septic shock. CONCLUSIONS Here, we illustrate a new mouse model for conditional platelet depletion, and implicate platelets as important participants in the immune response to bacterial blood infections.
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Affiliation(s)
- Leah M. Wuescher
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, 43614, USA
| | - Akira Takashima
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, 43614, USA
| | - Randall G. Worth
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, 43614, USA
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191
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The innate defense antimicrobial peptides hBD3 and RNase7 are induced in human umbilical vein endothelial cells by classical inflammatory cytokines but not Th17 cytokines. Microbes Infect 2015; 17:353-9. [PMID: 25637949 DOI: 10.1016/j.micinf.2015.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 12/12/2022]
Abstract
Antimicrobial peptides are multifunctional effector molecules of innate immunity. In this study we investigated whether endothelial cells actively contribute to innate defense mechanisms by expression of antimicrobial peptides. We therefore stimulated human umbilical vein endothelial cells (HUVEC) with inflammatory cytokines, Th17 cytokines, heat-inactivated bacteria, bacterial conditioned medium (BCM) of Staphylococcus aureus and Streptococcus sanguinis, and lipoteichoic acid (LTA). Stimulation with single cytokines induced discrete expression of human β-defensin 3 (hBD3) by IFN-γ or IL-1β and of ribonuclease 7 (RNase7) by TNF-α without any effects on LL-37 gene expression. Stronger hBD3 and RNase7 induction was observed after combined stimulation with IL-1β, TNF-α and IFN-γ and was confirmed by high hBD3 and RNase7 peptide levels in cell culture supernatants. In contrast, Th17 cytokines or stimulation with LTA did not result in AMP production. Moreover, only BCM of an invasive S. aureus bacteremia isolate induced hBD3 in HUVEC. We conclude that endothelial cells actively contribute to prevent dissemination of pathogens at the blood-tissue-barrier by production of AMPs that exhibit microbicidal and immunomodulatory functions. Further investigations should focus on tissue-specific AMP induction in different endothelial cell types, on pathogen-specific induction patterns and potentially involved pattern-recognition receptors of endothelial cells.
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192
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Ferdous F, Scott T. A comparative examination of thrombocyte/platelet immunity. Immunol Lett 2015; 163:32-9. [DOI: 10.1016/j.imlet.2014.11.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 10/30/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022]
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Abstract
Pathogenic Leptospira has the capacity to infect a broad range of mammalian hosts. Leptospirosis may appear as an acute, potentially fatal infection in accidental hosts, or progress into a chronic, largely asymptomatic infection in natural maintenance hosts. The course that Leptospira infection follows is dependent upon poorly understood factors, but is heavily influenced by both the host species and bacterial serovar involved in infection. Recognition of pathogen-associated molecular patterns (PAMPs) by a variety of host pattern recognition receptors (PRRs) activates the host immune system. The outcome of this response may result in bacterial clearance, limited bacterial colonization of a few target organs, principally the kidney, or induction of sepsis as the host succumbs to infection and dies. This chapter describes current knowledge of how the host recognizes Leptospira and responds to infection using innate and acquired immune responses. Aspects of immune-mediated pathology and pathogen strategies to evade the host immune response are also addressed.
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Affiliation(s)
- Richard L Zuerner
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University for Agricultural Sciences, 75007, Uppsala, Sweden,
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194
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Assinger A. Platelets and infection - an emerging role of platelets in viral infection. Front Immunol 2014; 5:649. [PMID: 25566260 PMCID: PMC4270245 DOI: 10.3389/fimmu.2014.00649] [Citation(s) in RCA: 252] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 12/05/2014] [Indexed: 12/23/2022] Open
Abstract
Platelets are anucleate blood cells that play a crucial role in the maintenance of hemostasis. While platelet activation and elevated platelet counts (thrombocytosis) are associated with increased risk of thrombotic complications, low platelet counts (thrombocytopenia) and several platelet function disorders increase the risk of bleeding. Over the last years, more and more evidence has emerged that platelets and their activation state can also modulate innate and adaptive immune responses and low platelet counts have been identified as a surrogate marker for poor prognosis in septic patients. Viral infections often coincide with platelet activation. Host inflammatory responses result in the release of platelet activating mediators and a pro-oxidative and pro-coagulant environment, which favors platelet activation. However, viruses can also directly interact with platelets and megakaryocytes and modulate their function. Furthermore, platelets can be activated by viral antigen-antibody complexes and in response to some viruses B-lymphocytes also generate anti-platelet antibodies. All these processes contributing to platelet activation result in increased platelet consumption and removal and often lead to thrombocytopenia, which is frequently observed during viral infection. However, virus-induced platelet activation does not only modulate platelet count but also shape immune responses. Platelets and their released products have been reported to directly and indirectly suppress infection and to support virus persistence in response to certain viruses, making platelets a double-edged sword during viral infections. This review aims to summarize the current knowledge on platelet interaction with different types of viruses, the viral impact on platelet activation, and platelet-mediated modulations of innate and adaptive immune responses.
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Affiliation(s)
- Alice Assinger
- Department of Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria ; Department of Medicine, Center for Molecular Medicine, Karolinska University Hospital , Stockholm , Sweden
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195
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Evaluation of antitumor activity of platelet microbicidal protein on the model of transplanted breast cancer in CBRB-Rb(8.17)1Iem mice. Pathol Oncol Res 2014; 21:827-30. [PMID: 25432548 DOI: 10.1007/s12253-014-9812-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/04/2014] [Indexed: 10/24/2022]
Abstract
Breast cancer is the most common women's cancer in the world. There is considerable current interest in developing anticancer agents with a new mode of action because of the development of resistance by cancer cells towards current anticancer drugs. Mamalian cells have been shown to contain small, cationic, microbicidal peptides. Antimicrobial peptides have drawn attention as a promising alternative to current antitumor agents. Such peptides have been isolated both from animal and human platelets and have been termed platelets microbicidal proteins (PMP). The aim of this work was to study antitumor activity of PMP in vivo on the model of mouse breast cancer in comparison with antitumor hexapeptide Arg-alpha-Asp-Lys-Val-Tyr-Arg (Immunofan). We demonstrated that the tumors treated with PMP were significant smaller than the control groups (P < 0.05). In experiments in vivo using CBRB-Rb(8.17)1Iem mice with transplanted tumors PMP inhibited tumor growth during the treatments and after its discontinuation. These findings indicate that PMP can exert antitumor effects. Therefore, PMP may be used for the development of therapy for the intervention of breast cancer.
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196
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Herter JM, Rossaint J, Zarbock A. Platelets in inflammation and immunity. J Thromb Haemost 2014; 12:1764-75. [PMID: 25224706 DOI: 10.1111/jth.12730] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 09/01/2014] [Indexed: 02/06/2023]
Abstract
The paradigm of platelets as mere mediators of hemostasis has long since been replaced by a dual role: hemostasis and inflammation. Now recognized as key players in innate and adaptive immune responses, platelets have the capacity to interact with almost all known immune cells. These platelet-immune cell interactions represent a hallmark of immunity, as they can potently enhance immune cell functions and, in some cases, even constitute a prerequisite for host defense mechanisms such as NETosis. In addition, recent studies have revealed a new role for platelets in immunity: They are ubiquitous sentinels and rapid first-line immune responders, as platelet-pathogen interactions within the vasculature appear to precede all other host defense mechanisms. Here, we discuss recent advances in our understanding of platelets as inflammatory cells, and provide an exemplary review of their role in acute inflammation.
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Affiliation(s)
- J M Herter
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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197
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Abstract
Thrombocytopenia is a common finding in sepsis and associated with a worse outcome. We used a mouse model of pneumonia-derived sepsis caused by the human pathogen Klebsiella pneumoniae to study the role of platelets in host response to sepsis. Platelet counts (PCs) were reduced to less than a median of 5 × 10(9)/L or to 5 to 13 × 10(9)/L by administration of a depleting antibody in mice infected with Klebsiella via the airways. Thrombocytopenia was associated with strongly impaired survival during pneumonia-derived sepsis proportional to the extent of platelet depletion. Thrombocytopenic mice demonstrated PC-dependent enhanced bacterial growth in lungs, blood, and distant organs. Severe thrombocytopenia resulted in hemorrhage at the primary site of infection, but not in distant organs. PCs of 5 to 13 × 10(9)/L were sufficient to largely maintain hemostasis in infected lungs. Thrombocytopenia did not influence lung inflammation or neutrophil recruitment and did not attenuate local or systemic activation of coagulation or the vascular endothelium. PCs <5 × 10(9)/L even resulted in enhanced coagulation and endothelial cell activation, which coincided with increased proinflammatory cytokine levels. In accordance, low PCs in whole blood enhanced Klebsiella-induced cytokine release in vitro. These data suggest that platelets play an important role in host defense to Klebsiella pneumosepsis.
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198
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Klarström Engström K, Khalaf H, Kälvegren H, Bengtsson T. The role of Porphyromonas gingivalis gingipains in platelet activation and innate immune modulation. Mol Oral Microbiol 2014; 30:62-73. [PMID: 25043711 DOI: 10.1111/omi.12067] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2014] [Indexed: 12/31/2022]
Abstract
Platelets are considered to have important functions in inflammatory processes and as actors in the innate immunity. Several studies have shown associations between cardiovascular disease and periodontitis, where the oral anaerobic pathogen Porphyromonas gingivalis has a prominent role in modulating the immune response. Porphyromonas gingivalis has been found in atherosclerotic plaques, indicating spreading of the pathogen via the circulation, with an ability to interact with and activate platelets via e.g. Toll-like receptors (TLR) and protease-activated receptors. We aimed to evaluate how the cysteine proteases, gingipains, of P. gingivalis affect platelets in terms of activation and chemokine secretion, and to further investigate the mechanisms of platelet-bacteria interaction. This study shows that primary features of platelet activation, i.e. changes in intracellular free calcium and aggregation, are affected by P. gingivalis and that arg-gingipains are of great importance for the ability of the bacterium to activate platelets. The P. gingivalis induced a release of the chemokine RANTES, however, to a much lower extent compared with the TLR2/1-agonist Pam3 CSK4 , which evoked a time-dependent release of the chemokine. Interestingly, the TLR2/1-evoked response was abolished by a following addition of viable P. gingivalis wild-types and gingipain mutants, showing that both Rgp and Kgp cleave the secreted chemokine. We also demonstrate that Pam3 CSK4 -stimulated platelets release migration inhibitory factor and plasminogen activator inhibitor-1, and that also these responses were antagonized by P. gingivalis. These results supports immune-modulatory activities of P. gingivalis and further clarify platelets as active players in innate immunity and in sensing bacterial infections, and as target cells in inflammatory reactions induced by P. gingivalis infection.
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Affiliation(s)
- K Klarström Engström
- Department of Biomedicine, School of Health and Medical Sciences, Örebro University, Örebro, Sweden
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199
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González-Navajas JM, Corr MP, Raz E. The immediate protective response to microbial challenge. Eur J Immunol 2014; 44:2536-49. [PMID: 24965684 DOI: 10.1002/eji.201344291] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 06/02/2014] [Accepted: 06/20/2014] [Indexed: 03/20/2024]
Abstract
The innate immune system detects infection and tissue injury through different families of pattern-recognition receptors (PRRs), such as Toll-like receptors. Most PRR-mediated responses initiate elaborate processes of signaling, transcription, translation, and secretion of effector mediators, which together require time to achieve. Therefore, PRR-mediated processes are not active in the early phases of infection. These considerations raise the question of how the host limits microbial replication and invasion during this critical period. Here, we examine the crucial defense mechanisms, such as antimicrobial peptides or extracellular traps, typically activated within minutes of the initial infection phase, which we term the "immediate protective response". Deficiencies in different components of the immediate protective response are often associated with severe and recurrent infectious diseases in humans, highlighting their physiologic importance.
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Affiliation(s)
- José M González-Navajas
- Networked Biomedical Research Center for Hepatic and Digestive Diseases (CIBERehd), Hospital General de Alicante, Alicante, Spain; Division of Rheumatology, Allergy and Immunology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
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200
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Calpain activity and Toll-like receptor 4 expression in platelet regulate haemostatic situation in patients undergoing cardiac surgery and coagulation in mice. Mediators Inflamm 2014; 2014:484510. [PMID: 25258477 PMCID: PMC4167458 DOI: 10.1155/2014/484510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/07/2014] [Accepted: 08/07/2014] [Indexed: 01/02/2023] Open
Abstract
Human platelets express Toll-like receptors (TLR) 4. However, the mechanism by which TLR4 directly affects platelet aggregation and blood coagulation remains to be explored. Therefore, in this study, we evaluated the platelet TLR4 expression in patients who underwent CABG surgery; we explored the correlation between platelet TLR4 expression and the early outcomes in hospital of patients. Additionally, C57BL/6 and C57BL/6-TlrLPS−/− mice were used to explore the roles of platelet TLR4 in coagulation by platelet aggregometry and rotation thromboelastometry. In conclusion, our results highlight the important roles of TLR4 in blood coagulation and platelet function. Of clinical relevance, we also explored novel roles for platelet TLR4 that are associated with early outcomes in cardiac surgery.
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