Dna synthesis and multinucleation in embryonic stem cell-derived cardiomyocytes. Klug, Michael G., Mark H. Soonpaa, and Loren J. Field. Krannert Institute of Cardiology, Indiana University School of Medicine, 1111 West 10th Street, Indianapolis, Indiana
APStracts 2:0250H, 1995.
The proliferative capacity of embryonic stem (ES) cell derived cardiomyocytes was assessed. Enriched preparations of cardiomyocytes were isolated by micro-dissection of the cardiogenic regions of cultured embryoid bodies (EBs). The identity of the isolated cells was established by immunocytology, and mitotic activity was monitored by 3H-thymidine incorpo ration and pulse-chase experiments. ES derived cardiomyocytes were mitotically active and predominately mononucleated at 11 days post cardiogenic induction. By 21 days post induc tion cardiomyocyte DNA synthesis was markedly decreased, with a concomitant increase in the percentage of multinucleated cells. Interestingly, the duration of active cardiomyocyte redupli cation in the ES system appeared to be roughly similar to that observed previously during normal murine cardiogenesis. Given these observations, as well as the genetic tractability of ES cells, ES -derived cardiogenesis might provide a useful in vitro system with which to assess the molecular regulation of the cardiomyocyte cell cycle.

Received 9 January 1995; accepted in final form 1 June 1995.
APS Manuscript Number H13-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on  6 July 1995.