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Role of matrix metalloproteinases and their tissue inhibitor of metalloproteinases in myxomatous change of cardiac floppy valves
Author(s) -
Togashi Mayuko,
Tamura Koichi,
Nitta Takashi,
Ishizaki Masamichi,
Sugisaki Yuichi,
Fukuda Yuh
Publication year - 2007
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1111/j.1440-1827.2007.02096.x
Subject(s) - matrix metalloproteinase , pathology , medicine , matrix (chemical analysis) , anatomy , chemistry , chromatography
To clarify the underlying cause of myxomatous changes in cardiac floppy valves, the expression of the matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) was investigated in cardiac valves. Valves were obtained from nine patients with floppy valves, from 13 patients with other valvular disease types, and from four patients with normal valves. Immunohistochemical analyses for MMP‐2, MMP‐9, TIMP‐1, and TIMP‐2, and gelatin zymography for MMP‐2 and MMP‐9 were performed. Compared with the spongiosa of normal valves, the myxomatous area of floppy valves had stronger immunohistochemical reaction to MMP‐2 and MMP‐9, and weaker reaction to TIMP‐2. Activated MMP‐2 and MMP‐9 were detected in eight out of nine cases of floppy valves. Activated MMP‐2 was detected at low levels in two cases of normal valves showing mild expansion of the spongiosa without macroscopic floppiness. The ratio of active/total MMP‐2 and MMP‐9 increased in floppy valves compared with normal valves. These results suggest that the imbalance between MMP and TIMP and the increased activity of MMP‐2 and MMP‐9 may correlate with myxomatous changes observed in floppy valves. Valves with a slight myxomatous change and activated MMP‐2 may develop into floppy valves with increases in the activity of MMP.