Morphologic and mechanical characteristics of engineered bovine arteries

Objective: The ideal small-caliber arterial graft remains elusive despite s everal decades of intense research. A novel approach to the development of small-caliber arterial prostheses with a biomimetic system for in vitro ves sel culture has recently been described. In this study we examined the effe cts of culture time and tissue culture scaffolding on engineered vessel mor phology and function and found that these parameters greatly influence the function of engineered vessels. Methods: This report describes the effects of culture time and scaffold typ e on vessel morphology cellular differentiation, and vessel mechanical char acteristics. Engineered vessels were cultured from bovine aortic smooth mus cle cells (SMCs) and endothelial cells that were seeded onto biodegradable polymer scaffolds and cultured under physiologically pulsatile conditions. Engineered vessels were subjected to histologic, ultrastructural, immunocyt ochemical, and mechanical analyses. Results: Vessel morphology and mechanical characteristics improved as time in culture increased to 8 weeks. SMCs in the engineered vessel wall were or ganized into a highly lamellar structure, with cells separated by alternati ng layers of collagen fibrils. Polymer scaffold remnants were present in ve ssels cultured for 8 weeks, and SMCs that were in proximity to polymer renm ants exhibited a dedifferentiated phenotype. Conclusions: These findings aid in the systematic understandings of the eff ects of in vitro parameters on engineered vessels and will be useful for th e translation of vessel culture techniques to human cells for the developme nt of autologous human vascular grafts.