Abnormalities in elastic fibers and other connective-tissue components of floppy mitral valve

Am Heart J. 1995 Jun;129(6):1149-58. doi: 10.1016/0002-8703(95)90397-6.

Abstract

Histologic, immunohistochemical, and ultrastructural studies were performed on 12 floppy mitral valves, 4 mitral valves showing focal myxomatous changes without prolapse, and 3 normal mitral valves. All floppy mitral valves were thickened by deposits of proteoglycans and also showed diverse structural abnormalities in collagen and elastic fibers. From these observations we conclude that (1) the structure of all major components of connective tissue in floppy mitral valves is abnormal; (2) alterations in collagen and accumulations of proteoglycans are nonspecific changes that may be caused by the abnormal mechanical forces to which floppy mitral valves are subjected because of their excessively large surface area; (3) the presence of excessive amounts of proteoglycans may interfere with the normal assembly of collagen and elastic fibers; (4) abnormalities of elastic fibers resemble those in other conditions characterized by structural dilatation or tissue expansion; and (5) alterations in elastin could result from defective formation, increased degradation, or both.

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Actin Cytoskeleton / ultrastructure
  • Adult
  • Aged
  • Aged, 80 and over
  • Chordae Tendineae / metabolism
  • Chordae Tendineae / pathology
  • Chordae Tendineae / ultrastructure
  • Collagen / metabolism
  • Connective Tissue / abnormalities
  • Connective Tissue / metabolism
  • Connective Tissue / pathology
  • Connective Tissue / ultrastructure
  • Cytoplasmic Granules / metabolism
  • Cytoplasmic Granules / ultrastructure
  • Dilatation, Pathologic / metabolism
  • Dilatation, Pathologic / pathology
  • Elastic Tissue / abnormalities*
  • Elastic Tissue / metabolism
  • Elastic Tissue / pathology
  • Elastic Tissue / ultrastructure
  • Elastin / metabolism
  • Endothelium / anatomy & histology
  • Endothelium / metabolism
  • Endothelium / ultrastructure
  • Female
  • Heart Valve Diseases / metabolism
  • Heart Valve Diseases / pathology
  • Humans
  • Immunohistochemistry
  • Male
  • Microscopy, Electron
  • Middle Aged
  • Mitral Valve / anatomy & histology
  • Mitral Valve / metabolism
  • Mitral Valve / ultrastructure
  • Mitral Valve Prolapse / metabolism
  • Mitral Valve Prolapse / pathology*
  • Proteoglycans / metabolism
  • Stress, Mechanical

Substances

  • Proteoglycans
  • Collagen
  • Elastin