Determining the fate of seeded cells in venous tissue-engineered vascular grafts using serial MRI.

A major limitation of tissue engineering research is the lack of noninvasive monitoring techniques for observations of dynamic changes in single tissue-engineered constructs. We use cellular magnetic resonance imaging (MRI) to track the fate of cells seeded onto functional tissue-engineered vascular grafts (TEVGs) through serial imaging. After in vitro optimization, murine macrophages were labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles and seeded onto scaffolds that were surgically implanted as inferior vena cava interposition grafts in SCID/bg mice.

Characterizing the inflammatory reaction in explanted Medtronic Freestyle stentless porcine aortic bioprosthesis over a 6-year period.

Background: The Medtronic Freestyle valve is a stentless porcine valve with reportedly excellent clinical and hemodynamic results, but little has been reported about its long-term pathology.

Methods: Seventeen Freestyle valves were explanted (from 2003 to 2009) and reviewed to assess reasons for bioprosthesis failure. All valves were examined in detail, using histochemistry and immunohistochemistry to identify morphological changes, as well as cellular and humoral responses.