Previous studies in several different species have shown reduced extractability of
collagens in some types of
cardiac hypertrophy (volume overload) but not others (pressure overload). The objective of the present study was to examine
collagen proteins from the same species (minipigs) with both pressure-overload- and volume-overload-induced
cardiac hypertrophy.
Hypertrophy was induced by two methods: thoracic banding of the aorta to create pressure overload and arteriovenous shunt to cause volume overload in a porcine model.
Collagen types I, III, IV, and V were isolated by
pepsin digestion from normal and hypertrophied pig left ventricle tissues. Types I and III
collagens from normal and hypertrophied samples, when separated from types IV and V, were digested with
cyanogen bromide (CB), and the
peptides were examined.
Collagen concentration was increased in myocardium removed from hearts subjected to volume overload and unchanged in hearts subjected to pressure overload. The extractability of total
collagen was unaffected in pressure-overloaded left ventricles but lower in samples from volume-overloaded hearts. CB digestion cleaved all of the types I and III
collagens into similar smaller CB
peptides with the exception of a 100-kDa
peptide that was observed in both control and hypertrophied hearts. This
peptide corresponds to one of the high-molecular-weight
peptides found in canine heart tissue. The mature
collagen cross-link
hydroxylysylpyridinoline (HP) was identified in normal and hypertrophied types I and III
collagen from porcine sources. Pressure-overload- and volume-overload-induced
cardiac hypertrophy in the pig produced different alterations in the extracellular matrix.(ABSTRACT TRUNCATED AT 250 WORDS)