| Thyroid hormone is required for growth adaptation to pressure load in the ovine fetal heart. | |
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MedLine Citation:
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PMID: 23104936 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Thyroid hormone exerts broad effects on the adult heart, however little is known regarding the role of thyroid hormone on regulating cardiac growth early in development and in response to pathophysiological conditions. To address this issue, we determined the effects of fetal thyroidectomy on cardiac growth and growth related gene expression in control and pulmonary artery banded fetal sheep. Fetal thyroidectomy (THX) and placement of a restrictive pulmonary artery band (PAB) was performed at 126 ± 1 d gestation (term 145 d). Four groups of animals (n = 5-6 in each group): 1) control; 2) fetal THX; 3) fetal PAB; and 4) fetal PAB + THX; were monitored for 1 week prior to being euthanized. Fetal heart rate was significantly lower in the two THX groups compared with the non-THX groups while mean arterial blood pressure was similar among groups. Combined left and right ventricle free wall + septum weight, expressed per kg fetal weight, was significantly increased in PAB (6.27 ± 0.85 g/kg) compared to control animals (4.72 ± 0.12 g/kg). THX significantly attenuated the increase in cardiac mass associated with PAB (4.94 ± 0.13 g/kg) while THX alone had no detectable effect on heart mass (4.95 ± 0.27 g/kg). The percentage of binucleated cardiomyocytes was significantly decreased in THX and PAB +THX (~16%) compared to the non-THX groups (~27%). No differences in levels of activated Akt, ERK or JNK were detected among the groups. Markers of cellular proliferation but not apoptosis or expression of growth related genes were lower in the THX and THX+ PAB groups relative to thyroid intact animals. These findings suggest that in the late gestation fetal heart, thyroid hormone has important cellular growth functions in both physiologic and pathophysiologic states. Specifically, thyroid hormone is required for adaptive fetal cardiac growth in response to pressure overload. |
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Authors:
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Jeffrey L Segar; Ken A Volk; Michael Hb Lipman; Thomas D Scholz |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-10-26 |
Journal Detail:
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Title: Experimental physiology Volume: - ISSN: 1469-445X ISO Abbreviation: Exp. Physiol. Publication Date: 2012 Oct |
Date Detail:
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Created Date: 2012-10-29 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9002940 Medline TA: Exp Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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University of Iowa. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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