title: Cultivation in rotating bioreactors promotes maintenance of cardiac myocyte electrophysiology and molecular properties.
abstract: We tested the hypothesis that cardiomyocytes maintained their phenotype better if cultured as three-dimensional tissue constructs than if cultured as confluent monolayers. Neonatal rat cardiomyocytes were cultured on biomaterial scaffolds in rotating bioreactors for 1 week, and resulting tissue constructs were compared with confluent monolayers and slices of native ventricular tissue with respect to proteins involved in cell metabolism (creatine kinase isoform MM), contractile function (sarcomeric myosin heavy chain), and intercellular communication (connexin 43), as well as action potential characteristics (e.g., membrane resting potential, maximum depolarization slope, and action potential duration), and macroscopic electrophysiological properties (maximum capture rate). The molecular and electrophysiological properties of cardiomyocytes cultured in tissue constructs, although inferior to those of native neonatal ventricles, were superior to those of the same cells cultured as monolayers. Construct levels of creatine kinase, myosin heavy chain, and connexin 43 were 40-60% as high as ventricle levels, whereas monolayer levels of the same proteins were only 11-20% as high. Construct action potential durations were 1.8-fold higher than those in ventricles, whereas monolayer action potential durations were 2.4-fold higher. Pharmacological studies using 4-aminopyridine showed that prolonged action potential duration and reduced maximum capture rate in tissue constructs as compared with native ventricles could be explained by decreased transient outward potassium current.
authors.affiliation: Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Nenad
authors.initials: N
authors.lastname: Bursac
authors.forename: Maria
authors.initials: M
authors.lastname: Papadaki
authors.forename: John A
authors.initials: JA
authors.lastname: White
authors.forename: Solomon R
authors.initials: SR
authors.lastname: Eisenberg
authors.forename: Gordana
authors.initials: G
authors.lastname: Vunjak-Novakovic
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Freed
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001683:Biological Clocks / Q000502:physiology; D019149:Bioreactors; D002450:Cell Communication / Q000502:physiology*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D048429:Cell Size; D003402:Creatine Kinase / Q000378:metabolism; D052283:Creatine Kinase, MM Form; D006329:Heart Conduction System / Q000502:physiology; D006352:Heart Ventricles / Q000166:cytology; D007527:Isoenzymes / Q000378:metabolism; D008564:Membrane Potentials; D008567:Membranes, Artificial; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012399:Rotation; D023822:Tissue Engineering / Q000379:methods*; D016276:Ventricular Function
chemical_list: D007527:Isoenzymes; D008567:Membranes, Artificial; D003402:Creatine Kinase; D052283:Creatine Kinase, MM Form; D018995:Myosin Heavy Chains