Cellular pathology of mitral valve prolapse.

BACKGROUND: Mitral valve prolapse (MVP) is the most frequent cause of chronic, pure, and isolated mitral regurgitation, and is estimated to affect more than 144 million individuals worldwide. This short review focuses in particular on the structural and cellular aspects of MVP in humans. The key microscopic change in MVP appears to occur in the fibrosa, on which the structural integrity of the entire valve depends. Recent discoveries showed that proteoglycans may play an active role in both MVP initiation and/or progression together with valvular interstitial cells. A full understanding of the cellular basis of MVP goes beyond a mere mechanicistic description of the disease, involving the transformation of resting fibroblasts into activated myofibroblasts.

CONCLUSIONS: Mitral valve could represent therefore an ideal environment to study early transformation phases of fibroblasts toward a protomyofibroblast phenotype.