Abstract 17738: Elastic Fibril Protein Fibulin-2 Expression is Increased in Fibro Elastic Deficiency Compared to Barlow's Disease- Implication in Disease Progression
Background: Degenerative mitral valve disease (DMVD) is surgically characterized as Fibro elastic deficiency (FED) or Barlow’s disease (BD). However, both conditions are structurally and functionally different in the extracellular matrix (ECM) composition. Nevertheless, the histopathological distinctions have not been well characterized. Fibulin-2, the elastic fibril-associated protein plays an essential role in the formation and integration of elastic fibril. Hypothesis: This study characterizes ECM composition, and tested the hypothesis that FED with chordae tendineae rupture (CTR) may have increased elastic fibril associated protein fibulin-2 expression.
Methods: Twenty-four human posterior mitral valve leaflets (12 from FED and 12 from BD) were studied. ECM composition and thickness was evaluated using H&E stain (for spongiosa layer) and elastic trichrome stain (for elastic fibrils). Fibulin-2 protein expression was graded by immunohistochemistry. Elastic fibril fragmentation and disorganization were also graded.
Results: Spongiosa layer thickness and extension into the ventricularis were increased in BD compared to FED (p<0.0001). Also the elastic fibril fragmentation (p<0.0001) and disorganization (p<0.006) were increased in BD. However, the expression of Fibulin-2 was significantly increased in FED compared to BD (p>0.0001) (Figure and Table).
Conclusions: Our data shows increased Fibulin-2 expression in FED with CTR may be associated with disease progression and severe mitral regurgitation. Ongoing evaluations studying the molecular signaling pathway will address the underlying mechanisms in the prolapsed leaflets from FED.
- © 2012 by American Heart Association, Inc.