title: Collagen content in normal, pressure, and pressure-volume overloaded developing human hearts.
abstract: Increased myocardial collagen accompanies pressure overload of the adult left ventricle. This phenomenon is poorly understood in infants. This study compares the myocardial volume fraction of collagen in infants who did not have primary heart disease with infants with isolated pressure overload of the right ventricle (tetralogy of Fallot [ToF]), and with infants with combined volume and pressure overload (aortic valve atresia [AVA]). The distribution of collagen in the neonatal myocardium was also determined. We measured the volume fraction of collagen from right ventricular biopsy specimens of cadaver hearts in normal infants (1 to 9 months old; n = 7), infants with ToF (1 day to 9 months old; n = 9), newborns with AVA (AVA-NB) (1 to 4 days old; n = 5), and older patients with AVA (AVA-I) (5 to 8 months old; n = 5). Myocardium from 3 patients undergoing repair of ToF (6 to 8 months old) was also analyzed. Specimens were stained with Masson's trichrome and myocardial volume fraction of collagen determined by point counting. Myocardial volume fraction of collagen was significantly higher (p = 0.02) in AVA-I patients (8.0 +/- 3.5%) versus normal (3.3 +/- 2.7%), ToF (3.2 +/- 1.8%), and AVA-NB (3.5 +/- 2.3%) patients. There was a tendency for increased collagen in the subendocardium, especially in AVA-I patients (p > 0.05). We conclude that patients with AVA-I have increased collagen relative to normal subjects, patients with ToF, and patients with AVA-NB, and that this increase is greatest in the subendocardium.
authors.affiliation: Department of Pediatrics, The University of Michigan Medical School, Ann Arbor, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Schwartz
authors.forename: D
authors.initials: D
authors.lastname: Gordon
authors.forename: R S
authors.initials: RS
authors.lastname: Mosca
authors.forename: E L
authors.initials: EL
authors.lastname: Bove
authors.forename: K P
authors.initials: KP
authors.lastname: Heidelberger
authors.forename: T J
authors.initials: TJ
authors.lastname: Kulik
mesh_terms: D001021:Aortic Valve / Q000002:abnormalities* / Q000737:chemistry; D001706:Biopsy; D001794:Blood Pressure; D002102:Cadaver; D002306:Cardiac Volume; D003094:Collagen / Q000032:analysis*; D004396:Coloring Agents; D004699:Endocardium / Q000737:chemistry / Q000473:pathology; D006352:Heart Ventricles / Q000737:chemistry / Q000473:pathology; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000378:metabolism; D007223:Infant; D007231:Infant, Newborn; D009206:Myocardium / Q000737:chemistry* / Q000473:pathology; D012835:Silver Nitrate; D013771:Tetralogy of Fallot / Q000378:metabolism*
chemical_list: D004396:Coloring Agents; C051037:Fontana-Masson stain; D003094:Collagen; D012835:Silver Nitrate