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  • 1. Bäck, Jennie
    et al.
    Huber-Lang, Markus
    Elgue, Graciela
    Kalbitz, Miriam
    Sanchez, Javier
    Nilsson Ekdahl, Kristina
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Nilsson, Bo
    Distinctive regulation of contact activation by antithrombin and C1-inhibitor on activated platelets and material surfaces2009In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 30, no 34, p. 6573-6580Article in journal (Refereed)
    Abstract [en]

    Activated human plate lets trigger FXII-mediated contactactivation, which leads to the generation of FXIIa–antithrombin (AT) and FXIa–AT complexes. This suggests that contactactivation takes place at different sites, on activatedplatelets and material surfaces, during therapeutic procedures involving biomaterials in contact with blood and is differentially regulated. Here we show that activation in platelet-poor plasma, platelet-rich plasma (PRP), and whole blood induced by glass, kaolin, and polyphosphate elicited high levels of FXIIa-C1-inhibitor (C1INH), low levels of FXIa–C1INH and KK–C1INH, and almost no AT complexes. Plateletactivation, in both PRP and blood, led to the formation of FXIIa–AT, FXIa–AT, and kallikrein (KK)–AT but almost no C1INH complexes. In severe trauma patients, FXIIa–AT and FXIa–AT were correlated with the release of thrombospondin-1 (TSP-1) from activatedplatelets. In contrast, FXIIa–C1INH complexes were detected when the FXIIa–AT levels were low. No correlations were found between FXIIa–C1INH and FXIIa–AT or TSP-1. Inhibition of FXIIa on material surfaces was also shown to affect the function of aggregating platelets. In conclusion, formation of FXIIa–AT and FXIIa–C1INH complexes can help to distinguish between contactactivation triggered by biomaterial surfaces and by activatedplatelets. Platelet aggregation studies also demonstrated that platelet function is influenced by material surface-mediated contactactivation and that generation of FXIIa–AT complexes may serve as a new biomarker for thrombotic reactions during therapeutic procedures employing biomaterial devices.

  • 2.
    Ekstrand-Hammarström, Barbro
    et al.
    Swedish Def Res Agcy, Linköping.
    Hong, Jaan
    Uppsala University.
    Davoodpour, Padideh
    Uppsala University.
    Sandholm, Kerstin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Bucht, Anders
    Umeå University.
    Nilsson, Bo
    Uppsala University.
    TiO2 nanoparticles tested in a novel screening whole human blood model of toxicity trigger adverse activation of the kallikrein system at low concentrations2015In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 51, p. 58-68Article in journal (Refereed)
    Abstract [en]

    There is a compelling need to understand and assess the toxicity of industrially produced nanoparticles (NPs). In order to appreciate the long-term effects of NPs, sensitive human-based screening tests that comprehensively map the NP properties are needed to detect possible toxic mechanisms. Animal models can only be used in a limited number of test applications and are subject to ethical concerns, and the interpretation of experiments in animals is also distorted by the species differences. Here, we present a novel easy-to-perform highly sensitive whole-blood model using fresh non-anticoagulated human blood, which most justly reflects complex biological cross talks in a human system. As a demonstrator of the tests versatility, we evaluated the toxicity of TiO2 NPs that are widely used in various applications and otherwise considered to have relatively low toxic properties. We show that TiO2 NPs at very low concentrations (50 ng/mL) induce strong activation of the contact system, which in this model elicits thromboinflammation. These data are in line with the finding of components of the contact system in the protein corona of the TiO2 NPs after exposure to blood. The contact system activation may lead to both thrombotic reactions and generation of bradykinin, thereby representing fuel for chronic inflammation in vivo and potentially long-term risk of autoimmunity, arteriosclerosis and cancer. These results support the notion that this novel whole-blood model represents an important contribution to testing of NP toxicity. (C) 2015 Elsevier Ltd. All rights reserved.

  • 3.
    Engberg, Anna E.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Region Skåne.
    Nilsson, Per H.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Oslo Univ Hosp, Rikshosp, Norway;Univ Oslo, Norway.
    Huang, Shan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Fromell, Karin
    Uppsala University.
    Hamad, Osama A.
    Uppsala University.
    Mollnes, Tom Eirik
    Univ Oslo, Norway;Univ Tromsö, Norway.
    Rosengren-Holmberg, Jenny P.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Swedish Natl Lab Forens Sci, Linköping.
    Sandholm, Kerstin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Teramura, Yuji
    Uppsala University;Univ Tokyo, Japan.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Nilsson, Bo
    Uppsala University.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Prediction of inflammatory responses induced by biomaterials in contact with human blood using protein fingerprint from plasma2015In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 36, p. 55-65Article in journal (Refereed)
    Abstract [en]

    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.

  • 4.
    Engberg, Anna E.
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Sandholm, Kerstin
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Bexborn, Fredrik
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Persson, Jenny
    Lund University.
    Nilsson, Bo
    Uppsala University.
    Lindahl, Gunnar
    Lund University.
    Nilsson Ekdahl, Kristina
    University of Kalmar, School of Pure and Applied Natural Sciences. Uppsala University.
    Inhibition of complement activation on a model biomaterial surface by streptococcal M protein-derived peptides2009In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 30, no 13, p. 2653-2659Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate a new approach to inhibit complement activation triggered by biomaterial surfaces in contact with blood. In order to inhibit complement activation initiated by the classical pathway (CP), we used streptococcal M protein-derived peptides that specifically bind human C4BP, an inhibitor of the CP. The peptides were used to coat polystyrene microtiter wells which served as a model biomaterial. The ability of coated peptides to bind C4BP and to attenuate complement activation via the CP (monitored as generation of fluid-phase C3a and binding of fragments of C3 and C4 to the surface) was investigated using diluted normal human serum, where complement activation by the AP is minimal, as well as serum from a patient lacking alternative pathway activation. Complement activation (all parameters) was significantly decreased in serum incubated in well surfaces coated with peptides. Total inhibition of complement activation was obtained at peptide coating concentrations as low as 1-5 mu g/mL. Successful use of Streptococcus-derived peptides shows that it is feasible to control complement activation at a model biomaterial surface by capturing autologous complement regulatory molecules from plasma. (C) 2009 Elsevier Ltd. All rights reserved.

  • 5.
    Huang, Shan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Engberg, Anna E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. University and Regional Laboratories Region Skåne.
    Jonsson, Nina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Sandholm, Kerstin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Mollnes, Tom Eirik
    Oslo University Hospital Rikshopsitalet, Norway;University of Oslo, Norway;Nordland Hospital, Norway; University of Tromsø, Norway;Norwegian University of Science and Technology, Norway.
    Fromell, Karin
    Uppsala University.
    Nilsson, Bo
    Uppsala University.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Reciprocal relationship between contact and complement system activation on artificial polymers exposed to whole human blood.2016In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 77, p. 111-119Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Inappropriate and uncontrolled activation of the cascade systems in the blood is a driving force in adverse inflammatory and thrombotic reactions elicited by biomaterials, but limited data are available on the activation of the contact system by polymers and the present study was undertaken to investigate these mechanisms in established models.

    METHODS: Polymer particles were incubated in (1) EDTA-plasma (10 mM) to monitor the adsorption of 20 selected proteins; (2) lepirudin-anticoagulated plasma to evaluate contact system activation, monitored by the formation of complexes between the generated proteases factor[F]XIIa, FXIa and kallikrein and the serpins C1-inhibitor [C1INH] and antithrombin [AT]; (3) lepirudin-anticoagulated whole blood to determine cytokine release.

    RESULTS: Strong negative correlations were found between 10 cytokines and the ratio of deposited FXII/C1INH, generated FXIIa-C1INH complexes, and kallikrein-C1INH complexes. Formation of FXIIa-C1INH complexes correlated negatively with the amount of C3a and positively with deposited IgG.

    CONCLUSIONS: A reciprocal relationship was found between activation of the contact system and the complement system induced by the polymers studied here. The ratios of FXII/C1INH or C4/C4BP, adsorbed from EDTA-plasma are useful surrogate markers for cytokine release and inflammatory response to materials intended for blood contact.

  • 6.
    Klapper, Yvonne
    et al.
    Uppsala University.
    Hamad, Osama A.
    Uppsala University.
    Teramura, Yuji
    Uppsala University.
    Leneweit, Gero
    Assoc Promot Canc Therapy, Germany.
    Nienhaus, G. Ulrich
    Karlsruhe Inst Technol KIT, Germany.
    Ricklin, Daniel
    Univ Penn, USA.
    Lambris, John D.
    Univ Penn, USA.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Nilsson, Bo
    Uppsala University.
    Mediation of a non-proteolytic activation of complement component C3 by phospholipid vesicles2014In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 35, no 11, p. 3688-3696Article in journal (Refereed)
    Abstract [en]

    Liposomes are becoming increasingly important as drug delivery systems, to target a drug to specific cells and tissues and thereby protecting the recipient from toxic effects of the contained drug. Liposome preparations have been described to activate complement. In this study, we have investigated complement activation triggered by neutral dimyristoyl-phosphocholine (DMPC) liposomes in human plasma and whole-blood systems. Incubation in plasma led to the generation of complement activation products (C3a and sC5b-9). Unexpectedly, investigations of surface-bound C3 revealed contact activated, conformationally changed C3 molecules on the liposomes. These changes were characterized by Western blotting with C3 monoclonal antibodies, and by incubating liposomes with purified native C3 and factors I and H. Quartz crystal microbalance analysis confirmed binding of C3 to planar DMPC surfaces. In addition, we demonstrated that DMPC liposomes bound to or were phagocytized by granulocytes in a complement-dependent manner, as evidenced by the use of complement inhibitors. In summary, we have shown that C3 is activated both by convertase-dependent cleavage, preferentially in the fluid phase, by mechanisms which are not well elucidated, and also by contact activation into C3(H2O) on the DMPC surface. In particular, this contact activation has implications for the therapeutic regulation of complement activation during liposome treatment. (C) 2013 Elsevier Ltd. All rights reserved.

  • 7.
    Nilsson, Per H.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Engberg, Anna E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bäck, Jennie
    Div. Clinical Immunology, Rudbeck Laboratory, University Hospital, Uppsala.
    Faxälv, Lars
    Department of Clinical Chemistry, Laboratory Medicine, University Hospital, Linköping.
    Lindahl, Tomas
    Department of Clinical Chemistry, Laboratory Medicine, University Hospital, Linköping.
    Nilsson, Bo
    Div. Clinical Immunology, Rudbeck Laboratory, University Hospital, Uppsala.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The creation of an antithrombotic surface by apyrase immobilization2010In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 31, no 16, p. 4484-4491Article in journal (Refereed)
    Abstract [en]

    Blood incompatibility reactions caused by surfaces often involve platelet activation and subsequent platelet-initiated activation of the coagulation and complement cascades. The goal of this study was to immobilize apyrase on a biomaterial surface in order to develop an enzymatically active surface that would have the capacity to inhibit platelet activation by degrading ADP. We were able to immobilize apyrase on a polystyrene surface with preservation of the enzymatic activity. We then analyzed the hemocompatibility of the apyrase surface and of control surfaces by incubation with platelet-rich plasma (PRP) or whole blood. Monitoring of markers of platelet, coagulation, and complement activation and staining of the surfaces revealed decreased levels of platelet and coagulation activation parameters on the apyrase surface. The formation of antithrombin-thrombin and antithrombin-factor XIa complexes and the extent of platelet consumption were significantly lower on the apyrase surface than on any of the control surfaces. No significant differences were seen in complement activation (C3a levels). Staining of the apyrase surface revealed low platelet adherence and no formation of granulocyte platelet complexes. These results demonstrate that it is possible to create an antithrombotic surface targeting the ADP amplification of platelet activation by immobilizing apyrase.

  • 8.
    Nilsson, Per H.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Magnusson, Peetra U
    Uppsala University.
    Qu, Hongchang
    University of Pennsylvania, USA.
    Iwata, Hiroo
    Kyoto University, Japan.
    Ricklin, Daniel
    University of Pennsylvania, USA.
    Hong, Jaan
    Uppsala University.
    Lambris, John D
    University of Pennsylvania, USA.
    Nilsson, Bo
    Uppsala University.
    Teramura, Yuji
    Uppsala University;Kyoto University, Japan.
    Autoregulation of thromboinflammation on biomaterial surfaces by a multicomponent therapeutic coating2013In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 34, no 4, p. 985-994Article in journal (Refereed)
    Abstract [en]

    Activation of the thrombotic and complement systems is the main recognition and effector mechanisms in the multiple adverse biological responses triggered when biomaterials or therapeutic cells come into blood contact. We have created a surface which is auto-protective to human innate immunity by combining three fundamentally different strategies, all developed by us previously, which have been shown to induce substantial, but incomplete hemocompatibility when used separately. In summary, we have conjugated a factor H-binding peptide; and an ADP-degrading enzyme; using a PEG linker on both material and cellular surfaces. When exposed to human whole blood, factor H was specifically recruited to the modified surfaces and inhibited complement attack. In addition, activation of platelets and coagulation was efficiently attenuated, by degrading ADP. Thus, by inhibiting thromboinflammation using a multicomponent approach, we have created a hybrid surface with the potential to greatly reduce incompatibility reactions involving biomaterials and transplantation.

  • 9.
    Shalaly, Nancy Dekki
    et al.
    KTH Royal Institute of Technology.
    Ria, Massimiliano
    Karolinska Institutet.
    Johansson, Ulrika
    KTH Royal Institute of Technology.
    Åvall, Karin
    Karolinska Institutet.
    Berggren, Per-Olof
    Karolinska Institutet.
    Hedhammar, My
    KTH Royal Institute of Technology ; Swedish University of Agricultural Sciences.
    Silk matrices promote formation of insulin-secreting islet-like clusters2016In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 90, p. 50-61Article in journal (Refereed)
    Abstract [en]

    Ex vivo expansion of endocrine cells constitutes an interesting alternative to be able to match the unmet need of transplantable pancreatic islets. However, endocrine cells become fragile once removed from their extracellular matrix (ECM) and typically become senescent and loose insulin expression during conventional 2D culture. Herein we develop a protocol where 3D silk matrices functionalized with ECM-derived motifs are used for generation of insulin-secreting islet-like clusters from mouse and human primary cells. The obtained clusters were shown to attain an islet-like spheroid shape and to maintain functional insulin release upon glucose stimulation in vitro. Furthermore, in vivo imaging of transplanted murine clusters showed engraftment with increasing vessel formation during time. There was no sign of cell death and the clusters maintained or increased in size throughout the period, thus suggesting a suitable cluster size for transplantation.

  • 10.
    Widhe, Mona
    et al.
    Swedish University of Agricultural Sciences.
    Johansson, Ulrika
    Swedish University of Agricultural Sciences.
    Hillerdahl, Carl-Olof
    Swedish University of Agricultural Sciences.
    Hedhammar, My
    Swedish University of Agricultural Sciences.
    Recombinant spider silk with cell binding motifs for specific adherence of cells2013In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 34, no 33, p. 8223-8234Article in journal (Refereed)
    Abstract [en]

    Silk matrices have previously been shown to possess general properties governing cell viability. However, many cell types also require specific adhesion sites for successful in vitro culture. Herein, we have shown that cell binding motifs can be genetically fused to a partial spider silk protein, 4RepCT, without affecting its ability to self-assemble into stable matrices directly in a physiological-like buffer. The incorporated motifs were exposed in the formed matrices, and available for binding of integrins. Four different human primary cell types; fibroblasts, keratinocytes, endothelial cells and Schwann cells, were applied to the matrices and investigated under serum-free culture conditions. Silk matrices with cell binding motifs, especially RGD, were shown to promote early adherence of cells, which formed stress fibers and distinct focal adhesion points. Schwann cells acquired most spread-out morphology on silk matrices with IKVAV, where significantly more viable cells were found, also when compared to wells coated with laminin. This strategy is thus suitable for development of matrices that allow screening of various cell binding motifs and their effect on different cell types.

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