Timing of cardiomyocyte growth, maturation, and attrition in perinatal sheep

Sonnet S. Jonker, Samantha Louey, George D. Giraud, Kent L. Thornburg, J. Job Faber

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


Studies in altricial rodents attribute dramatic changes in perinatal cardiomyocyte growth, maturation, and attrition to stimuli associated with birth. Our purpose was to determine whether birth is a critical trigger controlling perinatal cardiomyocyte growth, maturation and attrition in a precocial large mammal, sheep (Ovis aries). Hearts from0-61 d postnatal lambs were dissected or enzymatically dissociated.Cardiomyocytes weremeasured by micromorphometry, cell cycle activity assessed by immunohistochemistry, and nuclear number counted after DNA staining. Integration of this new data with published fetal data from our laboratory demonstrate that a newly appreciated >30% decrease in myocyte number occurred in the last 10 d of gestation (P < 0.0005) concomitant with an increase in cleaved poly (ADP-ribose) polymerase 1 (P < 0.05), indicative of apoptosis. Bisegmental linear regressions show that most changes in myocyte growth kinetics occur before birth (median = 15.2 d; P < 0.05). Right ventricular but not left ventricular cell number increases in the neonate, by 68% between birth and 60 d postnatal (P = 0.028). We conclude that in sheep few developmental changes in cardiomyocytes result frombirth, excepting the different postnatal degrees of free wall hypertrophy between the ventricles. Furthermore, myocyte number is reduced in both ventricles immediately before term, but proliferation increases myocyte number in the neonatal right ventricle. - Jonker, S. S., Louey, S., Giraud, G. D., Thornburg, K. L., Faber, J. J. Timing of cardiomyocyte growth, maturation, and attrition in perinatal sheep.

Original languageEnglish (US)
Pages (from-to)4346-4357
Number of pages12
JournalFASEB Journal
Issue number10
StatePublished - Oct 1 2015


  • Apoptosis
  • Cell number
  • Fetus
  • Neonate
  • Proliferation

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics


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