Porcine aortic valve interstitial cells in three-dimensional culture: comparison of phenotype with aortic smooth muscle cells.

BACKGROUND AND AIM OF THE STUDY: Recent heart valve tissue engineering efforts have involved populating scaffolds with cells isolated from vascular sources, though it is unclear whether cells from valvular origins behave similarly to vascular cells. The study aim was to compare the phenotype of porcine aortic valve interstitial cells (PAVICs) and porcine aortic smooth muscle cells (PASMCs) in two-dimensional cultures and within three-dimensional (3D) collagen gels.
METHODS: PASMCs and PAVICs were isolated from fresh pig hearts, and cultured in either tissue culture flasks or collagen constructs created with 1 x 10(6) cells/ml. After up to 10 days of culture, gels were lysed or cells isolated with collagenase. Expression of alpha-smooth muscle actin (alpha-SMA) and desmin were determined using flow cytometry and laser confocal microscopy. Gel compaction was measured up to day 6, and lysate was analyzed for protein, glycosaminoglycan (GAG), and cell number.
RESULTS: PAVICs and PASMCs compacted collagen gels similarly, and expressed similar levels of alpha-SMA but differing amounts of desmin. PAVICs appeared to produce more protein and GAGs than PASMCs over the six-day period in 3D culture. These results agreed well with previously published observations of interstitial cell behavior in vivo.
CONCLUSION: PAVICs possess both contractile properties and the ability to synthesize matrix components, highlighting their unique function in the demanding environment of the leaflet. Other potential cell sources for heart valve tissue engineering may not be able to mimic adequately some of these functions, and their use may impair tissue function in the long term.