Mechanical stimulation of organogenic cardiomyocyte growth in
vitro.
Vandenburgh, Herman H., Rosa Solerssi, Janet Shansky, John W. Adams,
and Scott A. Henderson.
Department of Pathology and Laboratory Medicine, Brown University
School of Medicine and The Miriam Hospital, Providence, RI 02906,
Department of Physiological Science, University of California at Los
Angeles, Los Angeles, CA 90024
APStracts 2:0365C, 1995.
Adherent cultures of neonatal rat cardiomyocytes were subjected to
progressive, unidirectional lengthening for 2 - 4 days in serum
-containing medium. This mechanical stretch (25% increase in initial
length each day) simulates the eccentric mechanical load placed on in
vivo heart cells by increases in postnatal blood pressure and volume.
The in vitro mechanical stimuli initiated a number of morphological
alterations in the confluent cardiomyocyte population which were
similar to those occurring during in vivo heart growth. These include
cardiomyocyte organization into parallel arrays of rod shaped cells,
increased cardiomyocyte binucleation, and cardiomyocyte hypertrophy
by longitudinal cell growth. Stretch stimulated DNA synthesis in the
noncardiomyocyte population but not in the cardiomyocytes. Myosin
heavy chain (MHC) content increased 62% over 4 days of stretch, and
included increased accumulation of both fetal [beta] MHC and adult
[alpha] MHC isoforms. This new model of stretch-induced cardiomyocyte
hypertrophy may assist in examining some of the complex mechanogenic
growth processes which occur in the rapidly enlarging neonatal heart.
Received 28 October 1994; accepted in final form 2 October 1995.
APS Manuscript Number C641-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95