Abstract 11746: Decellularized Dermis Extracellular Matrix Alloderm Mechanically Strengthens Biological Engineered Tunica Adventitia-Based Blood Vessels

Abstract

Introduction: Of the three layers of a mammalian artery, the tunica adventitia provides the most strength to prevent rupture of blood vessels under high pressures. The structural network of this outermost layer mainly consists of fibroblasts and collagen. Many groups have improved strength of their tissue engineered (TE) vessels by conditioning with pulsatile flow in bioreactors. Conditioning stimulates cellular collagen production; however, it is time-consuming ranging from 3-8 weeks. Dermis is comprised primarily of collagen providing skin with considerable strength. Hypothesis: We hypothesized inclusion of decellularized dermis, Alloderm, into TE vessels can increase the strength and thus decrease production time. Methods: To generate a TE adventitia vessel, we adapted our lab’s ring stacking method which creates tissue rings that are stacked to form a tubular, vascular constructs. Human dermal fibroblasts (HDFs) were used to form a cellular fibrin hydrogel in a petri dished with a central post. Alloderm was cut into a donut shape and placed on top of the hydrogel around the central post (Figure 1). Additional HDFs were placed on top of the hydrogel and Alloderm. Over 14 days the HDF monolayer rolled around the post into a ring. These Alloderm rings were stacked and adhered using fibrin glue to create a TE vessel. Results: TE vessel tensile strength was significantly higher with Alloderm than without: 1500 ± 262 kPa (n = 5) versus 67.9 ± 9.78 kPa (n = 5). Histology indicated Alloderm significantly increased total collagen content and fiber maturity compared to TE vessels without. Mechanical integrity of Alloderm rings was maintained for 4 weeks: tensile strength 2760 ± 1130 kPa. In comparison, native adventitia strength is 1430 ± 604 kPa. Conclusions: This work shows that decellularized dermis can successfully be incorporated into TE vessels. Additionally, inclusion of Alloderm significantly increases tissue strength and collagen content that is maintained over time.