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This Article Full Text Full Text (PDF) All Versions of this Article: 580/2/639    most recent jphysiol.2006.122200v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Louey, S. Articles by Thornburg, K. L. Search for Related Content PubMed PubMed Citation Articles by Louey, S. Articles by Thornburg, K. L. Related Collections Integrative

¹ Heart Research Center, and Departments of
² Medicine (Cardiovascular Medicine)
³ Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239-3098, USA
⁴ Portland VA Medical Center, Portland, OR 97207-1034, USA

Umbilicoplacental embolization (UPE) in sheep has been used to investigate the effects of placental insufficiency on fetal development. However, its specific effects on the heart have been little studied. The aim of this study was to determine the effects of placental insufficiency, induced by UPE, on cardiomyocyte size, maturation and proliferation. Instrumented fetal sheep underwent UPE for either 10 or 20 days. Hearts were collected at 125 ± 1 days (10 day group) or 136 ± 1 days (20 day group) of gestation (term 145 days). Cell size, maturational state (as measured by the proportion of binucleated myocytes) and cell cycle activity (as measured by positive staining of cells for Ki-67) were determined in dissociated cardiomyocytes. UPE fetuses were hypoxaemic, but mean arterial pressures were not different from controls. UPE fetuses were lighter than control fetuses (10 days: –21%, P < 0.05; 20 days: –27%, P < 0.01) and had smaller hearts, but heart weight was appropriate for body weight. Neither lengths nor widths were different between control and UPE cardiomyocytes at either age. Ten days of UPE did not significantly alter the proportion of binucleated myocytes or cell cycle activity in either ventricle. However, 20 days of UPE reduced cell cycle activity in both ventricles by 70% (P < 0.05); the proportion of binucleated myocytes was also lower in UPE fetuses at this age (left ventricle: 31.1 ± 12.0 versus 46.0 ± 6.6%, P < 0.05; right ventricle: 29.4 ± 12.3 versus 46.3 ± 5.3%, P < 0.05). It is concluded that in the absence of fetal arterial hypertension, placental insufficiency is associated with substantially depressed growth of the heart through suppressed proliferation and maturation of cardiomyocytes.

(Received 2 October 2006; accepted after revision 18 January 2007; first published online 18 January 2007)
Corresponding author S. Louey: Heart Research Center, L464, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239-3098, USA.  Email: loueys{at}ohsu.edu

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				J. L. Morrison, K. J. Botting, J. L. Dyer, S. J. Williams, K. L. Thornburg, and I. C. McMillen Restriction of placental function alters heart development in the sheep fetus Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2007; 293(1): R306 - R313. [Abstract] [Full Text] [PDF]