Tissue engineered vessels: Cells to telomeres

Abstract

Vascular diseases continue to affect people of all ages, and therapies are continually being improved. Cardiovascular tissue engineering is becoming an established field that will enable the replacement or modification of diseased tissues. Although commonly thought to affect older populations, cardiac disease afflicts many pediatric patients who come with a different set of needs. Particularly, with congenital defects, an engineered construct must be able to grow with the patient to avoid costly, repeated surgeries. Of the wide variety of congenital cardiac defects observed today, many concern the vessels in and around the heart. The selection of a proper cell source and attention to cellular lifespan are important factors that dictate the success of a vascular graft. Engineered blood vessels have been constructed from both synthetic and biological materials, using cells from human, bovine, and porcine species. Smooth muscle and endothelial cells taken from vessel explants, as well as cells derived from bone marrow, have been utilized to generate extracellular matrix components needed for conduit construction. The limited lifespan of these cells, especially after weeks in culture, has been addressed with the use of the telomerase enzyme. The catalytic subunit of telomerase, hTERT, has been used to maintain telomere length and consequently extend cellular lifespan. This review looks at current research that is expanding the vessel tissue engineering field by implementing novel use of cells and telomerase.