Assessment of decellularized pericardial extracellular matrix and poly(propylene fumarate) biohybrid for small-diameter vascular graft applications

Abstract

Autologous grafts are the current gold standard of care for coronary artery bypass graft surgeries, but are limited by availability and plagued by high failure rates. Similarly, tissue engineering approaches to small diameter vascular grafts using naturally derived and synthetic materials fall short, largely due to inappropriate mechanical properties. Alternatively, decellularized extracellular matrix from tissue is biocompatible and has comparable strength to vessels, while poly(propylene fumarate) (PPF) has shown promising results for vascular grafts. This study investigates the integration of decellularized pericardial extracellular matrix (dECM) and PPF to create a biohybrid scaffold (dECM+PPF) suitable for use as a small diameter vascular graft. Our method to decellularize the ECM was efficient at removing DNA content and donor variability, while preserving protein composition. PPF was characterized and added to dECM, where it acted to preserve dECM against degradative effects of collagenase without disturbing the material's overall mechanics. A transport study showed that diffusion occurs across dECM+PPF without any effect from collagenase. The modulus of dECM+PPF matched that of human coronary arteries and saphenous veins. dECM+PPF demonstrated ample circumferential stress, burst pressure, and suture retention strength to survive in vivo. An in vivo study showed re-endothelialization and tissue growth. Overall, the dECM+PPF biohybrid presents a robust solution to overcome the limitations of the current methods of treatment for small diameter vascular grafts. STATEMENT OF SIGNIFICANCE: In creating a dECM+PPF biohybrid graft, we have observed phenomena that will have a lasting impact within the scientific community. First, we found that we can reduce donor variability through decellularization, a unique use of the decellularization process. Additionally, we coupled a natural material with a synthetic polymer to capitalize on the benefits of each: the cues provided to cells and the ability to easily tune material properties, respectively. This principle can be applied to other materials in a variety of applications. Finally, we created an off-the-shelf alternative to autologous grafts with a newly developed material that has yet to be utilized in any scaffolds. Furthermore, bovine pericardium has not been investigated as a small diameter vascular graft.

Keywords: Biohybrid; Biomaterial; Extracellular matrix; Poly(propylene fumarate) (PPF); Vascular graft.