| 1. |
- Andersson, Linnea, et al.
(författare)
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Storage of Transfusion Platelet Concentrates is Associated with Complement Activation and Reduced Ability of Platelets to Respond to Protease-Activated Receptor-1 and Thromboxane A2 Receptor
- 2024
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 25:2
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Tidskriftsartikel (refereegranskat)abstract
- Platelet activation and the complement system are mutually dependent. Here, we investigated the effects of storage time on complement activation and platelet function in routinely produced platelet concentrates. The platelet concentrates (n = 10) were stored at 22 degrees C for seven days and assessed daily for complement and platelet activation markers. Additionally, platelet function was analyzed in terms of their responsiveness to protease-activated receptor-1 (PAR-1) and thromboxane A2 receptor (TXA(2)R) activation and their capacity to adhere to collagen. Complement activation increased over the storage period for all analyzed markers, including the C1rs/C1-INH complex (fold change (FC) = 1.9; p < 0.001), MASP-1/C1-INH complex (FC = 2.0; p < 0.001), C4c (FC = 1.8, p < 0.001), C3bc (FC = 4.0; p < 0.01), and soluble C5b-9 (FC = 1.7, p < 0.001). Furthermore, the levels of soluble platelet activation markers increased in the concentrates over the seven-day period, including neutrophil-activating peptide-2 (FC = 2.5; p < 0.0001), transforming growth factor beta 1 (FC = 1.9; p < 0.001) and platelet factor 4 (FC = 2.1; p < 0.0001). The ability of platelets to respond to activation, as measured by surface expression of CD62P and CD63, decreased by 19% and 24% (p < 0.05) for PAR-1 and 69-72% (p < 0.05) for TXA(2)R activation, respectively, on Day 7 compared to Day 1. The extent of platelet binding to collagen was not significantly impaired during storage. In conclusion, we demonstrated that complement activation increased during the storage of platelets, and this correlated with increased platelet activation and a reduced ability of the platelets to respond to, primarily, TXA(2)R activation.
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| 2. |
- Barratt-Due, Andreas, et al.
(författare)
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Dual inhibition of complement and Toll-like receptors as a novel approach to treat inflammatory diseases-C3 or C5 emerge together with CD14 as promising targets.
- 2017
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Ingår i: Journal of Leukocyte Biology. - 0741-5400 .- 1938-3673. ; 101:1, s. 193-204
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Tidskriftsartikel (refereegranskat)abstract
- The host is protected by pattern recognition systems, including complement and TLRs, which are closely cross-talking. If improperly activated, these systems might induce tissue damage and disease. Inhibition of single downstream proinflammatory cytokines, such as TNF, IL-1β, and IL-6, have failed in clinical sepsis trials, which might not be unexpected, given the substantial amounts of mediators involved in the pathogenesis of this condition. Instead, we have put forward a hypothesis of inhibition at the recognition phase by "dual blockade" of bottleneck molecules of complement and TLRs. By acting upstream and broadly, the dual blockade could be beneficial in conditions with improper or uncontrolled innate immune activation threatening the host. Key bottleneck molecules in these systems that could be targets for inhibition are the central complement molecules C3 and C5 and the important CD14 molecule, which is a coreceptor for several TLRs, including TLR4 and TLR2. This review summarizes current knowledge of inhibition of complement and TLRs alone and in combination, in both sterile and nonsterile inflammatory processes, where activation of these systems is of crucial importance for tissue damage and disease. Thus, dual blockade might provide a general, broad-acting therapeutic regimen against a number of diseases where innate immunity is improperly activated.
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| 3. |
- Berg, Aase, et al.
(författare)
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Complement Activation Correlates With Disease Severity and Contributes to Cytokine Responses in Plasmodium falciparum Malaria
- 2015
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Ingår i: The Internet Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1528-8366 .- 0022-1899 .- 1537-6613. ; 212:11, s. 1835-1840
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Tidskriftsartikel (refereegranskat)abstract
- The impact of complement activation and its possible relation to cytokine responses during malaria pathology was investigated in plasma samples from patients with confirmed Plasmodium falciparum malaria and in human whole-blood specimens stimulated with malaria-relevant agents ex vivo. Complement was significantly activated in the malaria cohort, compared with healthy controls, and was positively correlated with disease severity and with certain cytokines, in particular interleukin 8 (IL-8)/CXCL8. This was confirmed in ex vivo-stimulated blood specimens, in which complement inhibition significantly reduced IL-8/CXCL8 release. P. falciparum malaria is associated with systemic complement activation and complement-dependent release of inflammatory cytokines, of which IL-8/CXCL8 is particularly prominent.
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| 4. |
- Bexborn, Fredrik, et al.
(författare)
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Hirudin versus heparin for use in whole blood in vitro biocompatibility models
- 2009
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Ingår i: Journal of Biomedical Materials Research. Part A. - Hoboken, NJ, US : John Wiley & Sons Inc. - 1549-3296 .- 1552-4965. ; 89A:4, s. 951-959
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Tidskriftsartikel (refereegranskat)abstract
- Background: Heparin has traditionally been a widely used anticoagulant in blood research, but has been shown to be inappropriate for work with the complement system because of its complement-interacting properties. In this work, we have compared the effects of heparin with those of the specific thrombin inhibitor hirudin on complement and blood cells in vitro. Methods: Whole blood collected in the presence of hirudin (50 µg/mL) or heparin (1 IU/mL) was incubated in the slide chamber model. The plasma was analyzed for complement activation markers C3a and sC5b-9, and the polyvinylchloride test slides were stained for adhering cells. The integrity of the complement system was tested by incubating serum and hirudin-treated plasma in the presence of various activating agents.Results: In contrast to heparin, the addition of hirudin generally preserved the complement reactivity, and complement activation in hirudin plasma closely resembled that in normal serum. Importantly, immunochemical staining of surface-bound cells demonstrated the inducible expression of tissue factor on bound monocytes from hirudin-treated blood, an effect that was completely abolished in heparin-treated blood.Conclusion: Our results indicate that hirudin as an anticoagulant produces more physiological conditions than heparin, making hirudin well-suited for in vitro studies, especially those addressing the regulation of cellular processes.
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| 5. |
- Blom, Anna, et al.
(författare)
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A novel method for direct measurement of complement convertases activity in human serum.
- 2014
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Ingår i: Clinical and Experimental Immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 178:1, s. 142-153
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Tidskriftsartikel (refereegranskat)abstract
- Complement convertases are enzymatic complexes that play a central role in sustaining and amplification of the complement cascade. Impairment of complement function directly or indirectly leads to pathologic conditions including higher infection rate, kidney diseases, autoimmune- or neurodegenerative diseases and ischemia-reperfusion injury. An assay for direct measurement of activity of the convertases in patient sera is not available. Existing assays testing convertase function are based on purified complement components and thus, convertase formation occurs under non-physiological conditions. We designed a new assay, in which C5 blocking compounds enabled separation of the complement cascade into two phases: the first ending at the stage of C5 convertases and the second ending with membrane attack complex formation. Use of rabbit erythrocytes or antibody-sensitized sheep erythrocytes as the platforms for convertase formation enabled easy readout based on measurement of hemolysis. Thus, properties of patient sera could be studied directly regarding convertase activity and membrane attack complex formation. Another advantage of this assay was the possibility to screen for host factors such as C3 nephritic factor and other anti-complement autoantibodies, or gain-of-function mutations, which prolong half-live of complement convertases. Herein, we present proof of concept, detailed description and validation of this novel assay.
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| 6. |
- Chaban, Viktoriia, et al.
(författare)
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Escherichia coli-induced inflammatory responses are temperature-dependent in human whole blood ex vivo
- 2023
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Ingår i: Molecular Immunology. - : Elsevier. - 0161-5890 .- 1872-9142. ; 157, s. 70-77
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Tidskriftsartikel (refereegranskat)abstract
- Systemic inflammatory conditions are often associated with hypothermia or hyperthermia. Therapeutic hypothermia is used in post-cardiac arrest and some other acute diseases. There is a need for more knowledge concerning the effect of various temperatures on the acute inflammatory response. The complement system plays a crucial role in initiating the inflammatory response. We hypothesized that temperatures above and below the physiologic 37 & DEG;C affect complement activation and cytokine production ex vivo. Lepirudin-anticoagulated human whole blood from 10 healthy donors was incubated in the presence or absence of Escherichia coli at different temperatures (4 & DEG;C, 12 & DEG;C, 20 & DEG;C, 33 & DEG;C, 37 & DEG;C, 39 & DEG;C, and 41 & DEG;C). Complement activation was assessed by the terminal C5b-9 complement complex (TCC) and the alternative convertase C3bBbP using ELISA. Cytokines were measured using a 27-plex assay. Granulocyte and monocyte activation was evaluated by CD11b surface expression using flow cytometry. A consistent increase in complement activation was observed with rising temperature, reaching a maximum at 41 & DEG;C, both in the absence (C3bBbP p < 0.05) and presence (C3bBbP p < 0.05 and TCC p < 0.05) of E. coli. Temperature alone did not affect cytokine production, whereas incubation with E. coli significantly increased cytokine levels of IL-18, IL-2, IL-6, IL-8, IFN-& gamma;, and TNF at temperatures > 20 & DEG;C. Maximum increase occurred at 39 & DEG;C. However, a consistent decrease was observed at 41 & DEG;C, significant for IL-18 (p = 0.003). Granulocyte CD11b displayed the same temperature-dependent pattern as cytokines, with a corresponding increase in endothelial cell apoptosis and necrosis. Thus, blood temperature differentially determines the degree of complement activation and cytokine release.
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| 7. |
- Clarke, Gerard, et al.
(författare)
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Longitudinal Associations Between Persistent Post-Concussion Symptoms and Blood Biomarkers of Inflammation and CNS-Injury Following Mild Traumatic Brain Injury
- 2024
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Ingår i: Journal of neurotrauma. - 1557-9042. ; 41:7-8, s. 862-878
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Tidskriftsartikel (refereegranskat)abstract
- The aim of our study was to investigate the biological underpinnings of persistent post-concussion symptoms (PPCS) at 3 months following mild traumatic brain injury (mTBI). Patients (n = 192, 16-60 years) with mTBI, defined as Glasgow Coma Scale (GCS) score between 13 and 15, loss of consciousness (LOC)<30 min and post-traumatic amnesia (PTA)<24 hours were included. Blood samples were collected at admission (within 72 hours), 2 weeks and 3 months. From the blood, concentrations of blood biomarkers associated with CNS damage (GFAP, NFL and tau) and inflammation (IFN, IL-8, eotaxin, MIP-1, MCP-1, IP-10, IL-17A, IL-9, TNF, FGF-basic PDGF and IL-1ra) were obtained. Demographic and injury-related factors investigated were age, sex, GCS score, LOC, PTA duration, traumatic intracranial finding on MRI (within 72 hours), and extracranial injuries. Delta values, i.e., timepoint differences in biomarker concentrations between 2 weeks minus admission and 3 months minus admission, were also calculated. PPCS was assessed with the British Columbia Post-Concussion Symptom Inventory (BC-PSI). In single variable analyses, longer PTA duration and a higher proportion of intracranial findings on MRI were found in the PPCS group, but no single biomarker differentiated those with PPCS from those without. In multivariable models, female sex, longer PTA duration, MRI findings and lower GCS scores were associated with increased risk of PPCS. Inflammation markers, but not GFAP, NFL or tau, were associated with PPCS. At admission, higher concentrations of IL-8 and IL-9 and lower concentrations of TNF, IL-17a, and MCP-1 were associated with greater likelihood of PPCS; at 2 weeks, higher IL-8 and lower IFN were associated with PPCS; at 3 months, higher PDGF was associated with PPCS. Higher delta values of PDGF, IL-17A and FGF-basic at 2 weeks compared to admission, MCP-1 at 3 months compared to admission and TNF at 2 weeks and 3 months compared to admission were associated with greater likelihood of PPCS. Higher IL-9 delta values at both timepoint comparisons were negatively associated with PPCS. Discriminability of individual CNS-injury and inflammation biomarkers for PPCS was around chance level, while the optimal combination of biomarkers yielded AUCs between 0.62 and 0.73. We demonstrate a role of biological factors on PPCS, including both positive and negative effects of inflammation biomarkers that differed based on sampling timepoint after mTBI. PPCS was associated more with acute inflammatory processes, rather than ongoing inflammation or CNS-injury biomarkers. However, the modest discriminative ability of the models suggests other factors are more important in the development of PPCS.
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| 8. |
- Engberg, Anna E., 1982-, et al.
(författare)
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EVALUATION OF THE HEMOCOMPATIBILITY OF NOVEL POLYMERIC MATERIALS
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- When a biomaterial surface comes in contact with blood an immediate adsorption of plasma proteins to the surface will occur, and the cascade systems in the blood, such as the complement, coagulation and contact system, will be activated to various degrees. The intensity of this reaction will determine the hemocompatibility of the materials. Here we present an evaluation of the link between the composition, the physico-chemical properties and the protein adsorption properties of six newly synthesized polymers (P1-P6) and the hemocompatibility.The hemocompatibility of the polymeric surfaces was evaluated in human blood plasma and whole blood. Commercially available polyvinylchloride (PVC) was used as reference material. The hemocompatibility of the polymeric surfaces was evaluated with regard to complement activation (C3a and sC5-9 generation) and coagulation activation (platelet loss and TAT-formation) and cytokine productions (27 analytes in multiplex assay) after contact with whole blood. Contact activation was quantified by analyses of FXIIa-C1INH, FXIa-C1INH, and kallikrein-C1INH complexes.Polymers P2 (p<0.05 for C3a), P3, P5 and P6 showed less complement activation, and polymers P1 and P4 (p<0.05 for platelet loss), as well as P5 and P6 showed less coagulation activation compared with reference PVC. Polymers P1-P3 induced activation of the contact system, P3 being the most potent. Secretion of 17 cytokines including chemokines and growth factors were differentially influenced by the polymers, P1 and P3 being significantly (p<0.05) more compatible for five of the analytes.Collectively these data demonstrate that the composition of the polymers clearly leads to different biological properties as a consequence of distinctive physico-chemical properties and protein adsorption patterns.1
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| 9. |
- Engberg, Anna E., et al.
(författare)
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Prediction of inflammatory responses induced by biomaterials in contact with human blood using protein fingerprint from plasma
- 2015
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 36, s. 55-65
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Tidskriftsartikel (refereegranskat)abstract
- Inappropriate complement activation is often responsible for incompatibility reactions that occur when biomaterials are used. Complement activation is therefore a criterion included in legislation regarding biomaterials testing. However, no consensus is yet available regarding appropriate complement-activation-related test parameters. We examined protein adsorption in plasma and complement activation/cytokine release in whole blood incubated with well-characterized polymers. Strong correlations were found between the ratio of C4 to its inhibitor C4BP and generation of 10 (mainly pro-inflammatory) cytokines, including IL-17, IFN-gamma, and IL-6. The levels of complement activation products correlated weakly (C3a) or not at all (C5a, sC5b-9), confirming their poor predictive values. We have demonstrated a direct correlation between downstream biological effects and the proteins initially adhering to an artificial surface after contact with blood. Consequently, we propose the C4/C4BP ratio as a robust, predictor of biocompatibility with superior specificity and sensitivity over the current gold standard. (C) 2014 Elsevier Ltd. All rights reserved.
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| 10. |
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