Development of a Mouse Model for Evaluation of Small Diameter Vascular Grafts

Background

It is estimated that 80,000 individuals are unable to undergo life or limb saving bypass surgery because of inadequate small caliber synthetic vascular grafts. The use of tissue engineering methods has been proposed as a potential means of creating improved vascular conduits. We have developed a severe combined immunodeficiency (SCID) mouse aortic interposition model for initial evaluation and screening of small diameter vascular conduits in vivo.

Methods

Fifteen small diameter vascular conduits, approximately 1 mm in diameter and 10 mm in length, were implanted as infrarenal aortic interposition grafts for 1 to 35 days. Eight grafts were constructed using a decellularized ovine arterial tissue as a scaffold. Seven grafts were constructed from silastic tubing. Four grafts were composed of Polyurethane, and two were made of expanded polytetrafluroethylene. To explore noninvasive means of evaluating patency, grafts were selectively imaged using ultrasound and micro-computed tomography.

Results

All grafts were patent immediately post-operatively and at time of sacrifice. All imaging modalities were able to visualize the grafts and confirm patency. All specimens were sent for histology to evaluate neotissue formation and to correlate radiographic morphology with histological morphology.

Conclusions

The use of the SCID mouse model for initial evaluation of small caliber grafts is feasible and provides a cost effective rapid screening model with the added advantage of being able to use human cells in further studies.

Key Words: tissue engineering, SCID mice, polyurethane, silastic, microsurgery, vascular, grafts