Adhesion and proliferation of human umbilical vein endothelial cells on a novel electrospun biomaterial. A pilot study for vascular tissue engineering applications

Peripheral arterial disease is an occlusive condition of the lower extremities that worldwide affects, with increasing prevalence, millions of people who will develop critical limb ischemia (CLI). The prognosis for patients with CLI is poor, with 30% of patients undergoing amputation. Endovascular therapies are burdened by significant failure in short-term follow-up. On the other hand, intimal hyperplasia and thrombosis limit the application of available synthetic grafts in small-diameter (<6 mm) vascular districts. Finally, grafts <6 mm in diameter derived from cryopreserved venous or arterial allografts have shown poor clinical performance due to early thrombosis and late aneurysmal dilation. The design of novel biodegradable polymers with tailored properties could enable the fabrication of biomimetic scaffolds that mimic the composition and structure of native arterial extracellular matrix, so this study aimed at evaluating the adhesion and proliferation of human umbilical vein endothelial cells (HUVECs) seeded on a scaffold made of a novel electrospun biopolymer designed at the Department of Civil, Chemical, Environmental and Materials Engineering of our University (Prof. Nadia Lotti). Cell adhesion and proliferation on electrospun sheets were monitored using custom 3D printed scaffold supports, to avoid scaffold crumpling. Cell proliferation dynamics were found to be consistent with the expected behavior in laboratory plastic vessels. A range of initial seeding densities were tested to determine an optimal value to standardize a protocol for future investigations. Some replicates were performed under flow perfusion of the cell medium in a customized bioreactor system prototype, with unexpected results that still require explanation. Finally, an encouraging preliminary assessment of the endothelial molecular phenotype at the transcriptional level was also performed.