Type IV Collagen in Hypertrophic Cardiomyopathy.

Basement membrane of myocytes from patients with hypertrophic cardiomyopathy who died suddenly, seemed to be discontinuous by immunohistochemical methods. With the use of the sandwich immunoassay technique, we determined the frequency of type IV collagen and its influence on functional abnormality in 31 patients with hypertrophic cardiomyopathy and controls. Hypertrophic cardiomyopathy exhibited significantly increased serum type IV collagen compared with controls. A significant correlation was observed between serum type IV collagen and fractional shortening (r = -0.42 p < 0.05), and end-diastolic volume (r = 0.40 p < 0.05), DT (r = -0.50 p < 0.05). These data suggest that serum type IV collagen enhances clusters of cell-surface type IV collagen, including an alteration of the cytoskeleton, which may account for functional abnormalities in hypertrophic cardiomyopathy. Considering the fact that microscopic examination is unable to resolve the structure of the myocardial basement membrane, measurement of serum type IV collagen is thought to be useful in the diagnosis of myocardial basement membrane injury and the progression of hypertrophic cardiomyopathy.