Mitral valvular interstitial cells demonstrate regional, adhesional, and synthetic heterogeneity.

Background/aims: Because various regions of the mitral valve contain distinctive extracellular matrix enabling the tissues to withstand diverse mechanical environments, we investigated phenotype and matrix production of porcine valvular interstitial cells (VICs) from different regions.

Methods: VICswere isolated from the chordae (MCh), the center of the anterior leaflet (AlCtr), and the posterior leaflet free edge (PlFree), then assayed for metabolic, growth, and adhesion rates; collagen and glycosaminoglycan (GAG) production, and phenotype using biochemical assays, flow cytometry, and immunocytochemistry.

Results: The AlCtr VICs exhibited the fastest metabolism but slowest growth.

Synthesis of glycosaminoglycans in differently loaded regions of collagen gels seeded with valvular interstitial cells.

Cells respond to changes in mechanical strains by varying their production of extracellular matrix macromolecules. Because differences in strain patterns between mitral valve leaflets and chordae tendineae have been linked to different quantities and types of glycosaminoglycans (GAGs), we investigated the effects of various strain conditions on GAG synthesis by valvular interstitial cells (VICs) using an in vitro 3-dimensional tissue-engineering model. VICs from leaflets or chordae were seeded within collagen gels and subjected to uniaxial or biaxial static tension for 1 week.

Phenotypic characterization of isolated valvular interstitial cell subpopulations.

Background And Aim Of The Study: Valvular interstitial cells (VICs) demonstrate a heterogeneous range of phenotypes such as variable expression of smooth muscle alpha-actin (SMalphaA). Myofibroblast-like VICs, expressing high levels of SMalphaA, are thought to be involved in myxomatous degeneration of mitral valves. The inability to isolate specific cell types has restricted potential investigations of valvular disease mechanisms.

Age-related structural changes in cardiac valves: implications for tissue-engineered repairs.

Elderly patients would receive substantial benefits from tissue-engineered heart valves (TEHVs), but most TEHV research has not focused on applications for this growing patient population. There will be numerous technical challenges involved in developing TEHVs for the elderly, such as designing tissues to accommodate higher blood pressure and larger aortic roots that may be friable or calcified. Concomitant medications may also affect the biology of the TEHV.