Cell Culture Environment Effects on Valvular Interstitial Cells: Identifying Cells for Heart Valve Tissue Engineering

Valvular interstitial cells (VICs) are the major cellular component of heart valves involved in tissue repair and maintenance. These cells can exist in a number of different phenotypes.  A better understanding of the influence of isolation and in vitro culture conditions on VIC phenotypic expression will allow for identification of cell populations appropriate for tissue regeneration strategies.  We hypothesize that cell phenotype is influenced by harvesting method and subsequent culture environment.  Two widely employed methods for harvesting VICs are the collagenase and explants methods.  The collagenase method uses enzymatic digestion of the extracellular matrix (ECM) of the valve.  The explant method does not disrupt the ECM but allows the VICs to migrate from the valve tissue.  These two methods were performed concurrently and the isolated cells were examined for morphological and proliferation differences.  Brightfield image analysis showed that the collagenase method isolated cells that were more spread and evenly distributed when seeded on tissue culture polystyrene (TCPS), whereas the explants method produced cells that were less spread and formed discrete cellular multi-layer clusters.  Additionally, collagenase isolated cells displayed a higher rate of proliferation than the explant cells.  These results suggest that each method yields a unique VIC population.  Current studies focus on further characterization of phenotypic expression and ECM production. These studies will help determine the appropriate technique for harvesting VIC populations appropriate for tissue engineering applications.