Tissue Engineering of Vascular Grafts: A Case Report From Bench to Bedside and Back.

For over 25 years, our group has used regenerative medicine strategies to develop improved biomaterials for use in congenital heart surgery. Among other applications, we developed a tissue-engineered vascular graft (TEVG) by seeding tubular biodegradable polymeric scaffolds with autologous bone marrow-derived mononuclear cells. Results of our first-in-human study demonstrated feasibility as the TEVG transformed into a living vascular graft having an ability to grow, making it the first engineered graft with growth potential. Yet, outcomes of this first Food and Drug Administration-approved clinical trial evaluating safety revealed a prohibitively high incidence of early TEVG stenosis, preventing the widespread use of this promising technology. Mechanistic studies in mouse models provided important insight into the development of stenosis and enabled advanced computational models. Computational simulations suggested both a novel inflammation-driven, mechano-mediated process of in vivo TEVG development and an unexpected natural history, including spontaneous reversal of the stenosis. Based on these in vivo and in silico discoveries, we have been able to rationally design strategies for inhibiting TEVG stenosis that have been validated in preclinical large animal studies and translated to the clinic via a new Food and Drug Administration-approved clinical trial. This progress would not have been possible without the multidisciplinary approach, ranging from small to large animal models and computational simulations. This same process is expected to lead to further advances in scaffold design, and thus next generation TEVGs.