Use of autologous auricular chondrocytes for lining artificial surfaces: a feasibility study

Auricular elastic cartilage is a potential source of autologous cells for lining the luminal surfaces of cardiovascular prostheses. We tested this potential in vitro and in vivo using a left ventricular assist device (LVAD) and a calf model.

In vitro, auricular cartilage was harvested from the anesthetized ear of a calf, isolated, and cultured on tissue culture dishes. Primary chondrocytes were typed by immunocytochemistry, transferred into culture media, passaged twice, and seeded onto the blood-contacting luminal surfaces of four LVADs (HeartMate; Thoratec Corporation, Woburn, MA). Seeded cell linings were preconditioned under simulated flow conditions to promote cell adhesion to luminal surfaces. Seeding efficiency and cumulative cell loss under flow conditions were quantitated. In vivo, one of the four autologous chondrocyte-lined and preconditioned LVADs was implanted into the tissue-donor calf; run for 7 days; explanted; and evaluated grossly, by scanning electron microscopy, and by transmission electron microscopy.

The efficiency of seeding chondrocytes onto the luminal surfaces of the four LVADs was 95.11% +/- 4.23% (n = 4). Cumulative cell loss during preconditioning under flow conditions in vitro did not exceed 12% (n = 4). After 7 days of in vivo implantation, the luminal surfaces of the implanted LVAD demonstrated an intact, strongly adherent cellular lining.

Auricular elastic cartilage is a ready and easily accessible source of chondrocytes whose ability to produce collagen II and other important extracellular matrix constituents allows them to adhere strongly to the luminal surfaces of LVADs. The simple method of isolating and expanding auricular chondrocytes presented here could be used to provide strongly adherent autologous cell linings for LVADs and other cardiovascular devices. If and when chondrocytes can be genetically engineered to produce antithrombogenic factors and then used to line the luminal surfaces of LVADs or other cardiovascular prostheses, they may be able to improve the hemocompatibility of the blood-biomaterial interface in such devices. Our successful feasibility study in a calf model warrants further studies of this concept in vivo.