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Characterization of Cobblestone mitral valve interstitial cells.
S Zacks1, A Rosenthal, B Granton
1Department of Pathology, Banting and Best Diabetes Centre, Toronto, Ontario, Canada.
Archives of Pathology & Laboratory Medicine
|August 1, 1991
Summary
Mitral valve interstitial cells (MVICs) can form two distinct phenotypes in culture: cobblestone-shaped (CB) and elongated (EL). The CB type exhibits unique ultrastructural and molecular characteristics, suggesting a distinct MVIC phenotype.
Area of Science:
- Cardiovascular Biology
- Cell Biology
- Tissue Engineering
Background:
- Mitral valve interstitial cells (MVICs) play a crucial role in maintaining the structural integrity and function of the mitral valve.
- Understanding MVIC heterogeneity is essential for comprehending valve pathobiology and developing regenerative strategies.
Purpose of the Study:
- To investigate the phenotypic diversity of MVICs in cell culture.
- To characterize distinct MVIC subpopulations and their potential origins.
Main Methods:
- Harvesting MVICs from explants and culturing them through multiple passages.
- Morphological assessment of cell cultures, distinguishing between cobblestone-shaped (CB) and elongated (EL) types.
- Comparative analysis of cell adherence, trypsin sensitivity, and ultrastructural features (Golgi, endoplasmic reticulum, microfilaments).
- Immunohistochemical analysis for alpha-smooth muscle cell actin expression.
- Distinguishing MVICs from endothelial cells using specific markers and uptake assays.
Main Results:
- Two distinct MVIC phenotypes emerged in culture: MVICs-CB (cobblestone-shaped) and MVICs-EL (elongated).
- MVICs-CB displayed reduced initial adherence and increased trypsin sensitivity compared to MVICs-EL.
- Ultrastructural analysis revealed prominent Golgi and endoplasmic reticulum in MVICs-CB, with fewer microfilaments and significantly lower alpha-smooth muscle cell actin expression than MVICs-EL.
- MVICs-CB did not exhibit endothelial cell markers, confirming their distinct identity.
- Morphologically similar CB cells were observed in vivo within the mitral valve.
Conclusions:
- MVICs can differentiate into at least two distinct phenotypes in culture: MVICs-CB and MVICs-EL.
- The MVICs-CB phenotype represents a unique cell type within the mitral valve interstitial cell population, distinct from endothelial cells and medial smooth muscle cells.
- These findings highlight MVIC heterogeneity and its implications for mitral valve structure and function.