Increase in Cross-Linking of Type I and Type III Collagens Associated With

Types I, m, IV, and V collagen were isolated and characterized from eight normal dog hearts and seven with volume-overload hypertrophy. Animals with volume-overload hypertrophy were killed at a time when left ventricular end-diastolic pressure and stiffness were increased. The collagens were characterized by solubility properties, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, and enzyme-linked immunosorbent assay. The percentage of collagen obtained from canine left ventricles was decreased from 32.4 % in normal hearts to 15.0 % in hypertropbied hearts. We attribute this to a diminution in the extractability of types I and m collagen, which fell from 199.5 mg type I/g collagen and 76.4 mg type Ill/g collagen in normal hearts to 83.5 mg type I/g collagen and 26.4 mg type m/g collagen in hypertrophied hearts. The amount of types IV and V collagen isolated remained constant in both the control and arteriovenous shunt hearts averaging 15.7 mg type IV/g collagen and 32.1 mg type V/g collagen in control hearts and 12.5 mg type IV/g collagen and 28.9 mg type V/g collagen in hypertrophied hearts. The reduction in quantity of types I and III collagen probably reflects a greater degree of cross-Unking in these two types of collagen. Cyanogen bromide peptide analysis confirmed that there was an increase of high molecular weight cross-linke