Premium
In vivo imaging of infection‐induced cogulopathy in the microcirculation
Author(s) -
Jenne Craig N,
Davis Rachelle P,
McDonald Braedon
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.722.11
Subject(s) - neutrophil extracellular traps , fibrin , intravital microscopy , platelet , disseminated intravascular coagulation , coagulation , microcirculation , in vivo , pathology , platelet activation , immune system , microbiology and biotechnology , inflammation , biology , immunology , chemistry , medicine
Patients with systemic infection often develop disseminated intravascular coagulation (DIC), a condition leading to clot formation throughout the vasculature. This systemic coagulation can impair blood flow within the tissue microvasculature and has been associated with organ damage and dysfunction. Infection also triggers the release of Neutrophil Extracellular Traps (NETs) within the vasculature. NETs are comprised of extracellular DNA covered in a number of nuclear and antimicrobial proteins. This immune response is designed to catch and kill pathogens, but also has the potential to bind platelets and initiate coagulation. Currently, most studies are limited to the histological analysis of tissue sections or in vitro biochemical assays, providing only snapshots of these complex and dynamic processes. As such the specific interaction between NETs, platelets and coagulation are poorly understood. Using intravital microscopy (IVM), can directly visualize NET formation and fibrin deposition in real‐time, in the blood vessels of live mice following infection. Additionally, we have developed a novel imaging protocol using an enzyme‐activatable fluorescent probe to track the time and location of thrombin activation within the vasculature of live mice. Importantly, IVM allows us to understand not only the complex interactions between the pathogen, immunity and coagulation, but to also the effect of these interactions on vascular perfusion and tissue damage. Following i.v. challenge with bacteria, we measure significant NET deposition within the liver sinusoids. These NETs in turn activate thrombin leading to fibrin deposition, vascular occlusion and tissue damage. Importantly, treatments that prevent NET formation, break‐down NETs within the vasculature, or block key NET components significantly inhibit thrombin activation, improve perfusion and attenuate tissue damage. Support or Funding Information This work is supported by grants from the Critical Care Strategic Clinical Network and the Natural Sciences and Engineering Research Council of Canada (NSERC)