心筋症の病理 : Duchenne型筋ジストロフィー剖検例における心臓病変の検討

Dystrophinopaties are due to mutations in the dystrophin gene on chromosome Xp21.1 and comprise the allelic entities Duchenne muscular dystrophy （DMD）, Becker muscular dystrophy and X-linked dilated cardiomyopathy. In all three entities, the heart is affected to various degrees. The cardiac involvement in autopsy cases with DMD is described.
The cardiac weight of DMD varied widely. Of 285 hearts, 109 were atrophic, 107 were within normal range, and 69 were hypertrophic. The incidence of dilated cardiomyopathy, was highest in hypertrophic group. The posterior and lateral left ventricular wall were most extensively replaced by scar tissue, especially, the outer wall was more affected.
The microscopic characteristics of cardiac involvement in DMD was the replacement of myocardium by connective tissue. The degenerative changes of myocardial fiber and fatty infiltration were also noticed, but no regenerative myocardial fiber was observed.
Expression of NCAM, N-cadherin, β-catenin and connexin 43 were investigated immunohisohchemically. The immunoreactivity of these cell adhesion molecules was recognized at the intercalated disc of myocardial cell, although, in DMD the reactivity was weaker than in control cases. In DMD, reduced expression of these cell adhesion molecules can result in slowed ventricular conduction, which may contribute to the development of arrhythmia and heart failure.

四国医学雑誌 : http://www.tokushima-u.ac.jp/med/research/shikoku_acta_medica.html