Evaluation of synthetic vascular grafts in a mouse carotid grafting model

PLoS One. 2017 Mar 29;12(3):e0174773. doi: 10.1371/journal.pone.0174773. eCollection 2017.

Abstract

Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL) we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM) analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP). This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days). We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.

Publication types

  • Evaluation Study

MeSH terms

  • Actins / metabolism
  • Animals
  • Blood Vessel Prosthesis*
  • Carotid Arteries / surgery*
  • Cell Tracking / methods
  • Collagen / metabolism
  • Disease Models, Animal*
  • Female
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Hyperplasia
  • Luminescent Measurements / methods
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Microscopy, Electron, Scanning
  • Myocytes, Smooth Muscle / metabolism
  • Neointima / metabolism
  • Neointima / pathology
  • Polyesters / chemistry
  • Tunica Intima / metabolism
  • Tunica Intima / pathology
  • Tunica Intima / ultrastructure
  • Vascular Grafting / methods*
  • Vascular Patency

Substances

  • Actins
  • Polyesters
  • Green Fluorescent Proteins
  • polycaprolactone
  • Collagen

Grants and funding

This work was supported by funding from the National Health and Medical Research Council (APP1066174, MKCN). We also acknowledge a post-graduate scholarship from The Heart Research Institute (AHPC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.