Non- invasive in vivo analysis of a murine aortic graft using high resolution ultrasound microimaging.

INTRODUCTION: As yet, murine aortic grafts have merely been monitored histopathologically. The aim of our study was to examine how these grafts can be monitored in vivo and non-invasively by using high-resolution ultrasound microimaging to evaluate function and morphology. A further aim was to prove if this in vivo monitoring can be correlated to immunohistological data that indicates graft integrity.
METHODS: Murine infrarenal aortic isografts were orthotopically transplanted into 14 female mice (C57BL/6-Background) whereas a group of sham-operated animals (n = 10) served as controls. To assess the graft morphology and hemodynamics, we examined the mice over a post-operative period of 8 weeks with a sophisticated ultrasound system (Vevo 770, Visual Sonics).
RESULTS: The non-invasive graft monitoring was feasible in all transplanted mice. We could demonstrate a regular post-transplant graft function and morphology, such as anterior/posterior wall displacement and wall thickness. Mild alterations of anterior wall motion dynamics could only be observed at the site of distal graft anastomosis (8 weeks after grafting (transplant vs. sham mice: 0.02 mm ± 0.01 vs. 0.03 mm ± 0.01, p<0.05). However, the integrity of the entire graft wall could be confirmed by histopathological evaluation of the grafts.
CONCLUSIONS: With regard to graft patency, function and morphology, high resolution ultrasound microimaging has proven to be a valuable tool for longitudinal, non-invasive, in vivo graft monitoring in this murine aortic transplantation model. Consequently, this experimental animal model provides an excellent basis for molecular and pharmacological studies using genetically engineered mice. Crown