Heparin-coated cardiopulmonary bypass circuits selectively deplete the pattern recognition molecule ficolin-2 of the lectin complement pathway in vivo

Authors

  • E. Hein,

    1. Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Norway
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  • L. Munthe-Fog,

    1. Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Norway
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  • A. S. Thiara,

    1. Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
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  • A. E. Fiane,

    1. Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
    2. Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
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  • T. E. Mollnes,

    1. Department of Immunology, Oslo University Hospital Rikshospitalet, K.G.Jebsen IRC, University of Oslo, Oslo, Norway
    2. Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
    3. Research Laboratory, Nordland Hospital, Bodø, and Faculty of Health Sciences, K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway
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  • P. Garred

    Corresponding author
    1. Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Norway
    • Correspondence: P. Garred, Laboratory of Molecular Medicine, Department of Clinical Immunology, Section 7631, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen O, Denmark.

      E-mail: garred@post5.tele.dk

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Summary

The complement system can be activated via the lectin pathway by the recognition molecules mannose-binding lectin (MBL) and the ficolins. Ficolin-2 exhibits binding against a broad range of ligands, including biomaterials in vitro, and low ficolin-2 levels are associated with increased risk of infections. Thus, we investigated the biocompatibility of the recognition molecules of the lectin pathway in two different types of cardiopulmonary bypass circuits. Bloods were drawn at five time-points before, during and postoperatively from 30 patients undergoing elective cardiac surgery. Patients were randomized into two groups using different coatings of cardiopulmonary bypass circuits, Phisio® (phosphorylcholine polymer coating) and Bioline® (albumin-heparin coating). Concentrations of MBL, ficolin-1, −2 and −3 and soluble C3a and terminal complement complex (TCC) in plasma samples were measured. Ficolin-3-mediated complement activation potential was evaluated with C4, C3 and TCC as output. There was no significant difference between the two circuit materials regarding MBL, ficolin-1 and −3. In the Bioline® group the ficolin-2 levels decreased significantly after initiation of surgery (P < 0·0001) and remained reduced throughout the sampling period. This was not seen for Phisio®-coated circuits. Ficolin-3-mediated complement activation potential was reduced significantly in both groups after start of operation (P < 0·0001), whereas soluble C3a and TCC in the samples were increased (P < 0·0001). Ficolin-2 was depleted from plasma during cardiac surgery when using heparin-coated bypass circuits and did not reach baseline level 24 h postoperation. These findings may have implications for the postoperative susceptibility to infections in patients undergoing extracorporeal circulation procedures.

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