2008 Annual Meeting Abstracts
Immunohistological Characterization of Tissue Engineered Graft Remodeling in Severe Combined Immunodeficienct/beige (SCID/bg) Mouse Model
Rajendra F. Sawh-Martinez, BS, Narutoshi Hibino, MD, Jason Roh, MD, Tamar Mirensky, MD, Christopher Breuer, MD.
Yale University School of Medicine, New Haven, CT, USA.
Objective: To evaluate the ability of small diameter biodegradable tubular scaffolds to remodel and develop in-vivo.
Design: Non-Randomized Control Trial. Tissue Engineered grafts explants underwent immunohistological analysis for structural resemblance to mature, native vessels. Seeded and unseeded grafts were analyzed using markers for mature, native mouse tissue.
Setting: Basic Science Research Laboratory.
Patients: None. All animal studies were performed in accordance with the institutional guidelines for the use and care of animals, and the institutional review board approved the following surgical experimental procedure.
Interventions: Three-month old, female C.B-17 SCID/bg mice were anesthetized with an intraperitoneal injection of xylazine/ketamine. Animals were positioned supinely and opened with a midline abdominal incision. Using a 5X dissecting microscope, infrarenal inferior vena cava (IVC) was exposed, cross-clamped, and excised. Scaffolds were inserted as IVC interposition grafts using a running 10-0 nylon suture for the end-to-end proximal and distal anastomoses. The animals were recovered from surgery and maintained without the use of any anticoagulation or antiplatelet therapy.
Main Outcome Measure: Analysis of immunological cellular markers specific to mature, functional native tissue.
Results: The development of a confluent endothelium and smooth muscle layers were evident via vWF and SMA immunohistolochemical and immunofluorescence staining. Markers for calponin, eNOS and Ephrin B4 show a differentiated smooth muscle layer and functionally active venous endothelium. Compared to unseeded scaffolds, seeded scaffolds developed a more fully confluent endothelial layer, which is specifically venous.
Conclusions: These results mark the development of a small animal model for the study of vascular tissue engineering with results that are consistent with previous work in human clinical trials and large animal models that have shown seeding of scaffolds to significantly improve outcomes.