Expression of adrenoceptor subtypes in preterm piglet heart is different to term heart

Kim, Min Young, Finch, Angela M., Lumbers, Eugenie R., Boyce, Amanda C., Gibson, Karen J., Eiby, Yvonne A. and Lingwood, Barbara E. (2014) Expression of adrenoceptor subtypes in preterm piglet heart is different to term heart. PLoS One, 9 3: e92167.1-e92167.7. doi:10.1371/journal.pone.0092167


Author Kim, Min Young
Finch, Angela M.
Lumbers, Eugenie R.
Boyce, Amanda C.
Gibson, Karen J.
Eiby, Yvonne A.
Lingwood, Barbara E.
Title Expression of adrenoceptor subtypes in preterm piglet heart is different to term heart
Journal name PLoS One   Check publisher's open access policy
ISSN 1932-6203
Publication date 2014-03-26
Year available 2014
Sub-type Article (original research)
DOI 10.1371/journal.pone.0092167
Open Access Status DOI
Volume 9
Issue 3
Start page e92167.1
End page e92167.7
Total pages 7
Editor Katherine Yutzey
Place of publication San Francisco, CA, United States
Publisher Public Library of Science
Language eng
Abstract preterm delivery increases the risk of inadequate systemic blood flow and hypotension and many preterm infants fail to respond to conventional inotrope treatments. If the profile of cardiac adrenoceptor subtypes in the preterm neonate is different to that at term this may contribute to these clinical problems. This study measured mRNA expression of beta(1), beta(2), alpha(1A,) alpha(2A) and alpha(2B)-adrenoceptor subtypes by real time PCR in term (113d), preterm (91d) and preterm piglets (91d) exposed to maternal glucocorticoid treatment. Abundance of beta(1)-adrenoceptor binding sites in the left ventricle was measured using saturation binding assays. Relative abundance of beta(1)-adrenoceptor mRNA in untreated Preterm hearts was similar to 50% term abundance in both left and right ventricles (P<0.001). Trends in receptor binding site density measurements supported this observation (P=0.07). Glucocorticoid exposure increased beta(1)-adrenoceptor mRNA levels in the right ventricle of preterm hearts (P=0.008) but did not alter expression in the left ventricle (P>0.1). Relative abundance of alpha(1A) adrenoceptor rnRNA was the same in preterm and term piglet hearts (P= >0.1) but was reduced by maternal glucocorticoid treatment (P<0.01); alpha(2A)-adrenoceptor mRNA abundance was higher in untreated and glucocorticoid exposed preterm piglet hearts than in term piglets (P < 0.001). There was no difference between male and female piglets in mRNA abundance of any of he genes studied. In conclusion, there is reduced mRNA abundance of beta(1)-adrenoceptors in he preterm pig heart. If this lower expression of beta-adrenoceptars occurs in human preterm infants, it could explain their poor cardiovascular function and their frequent failure to respond to commonly used inotropes.
Formatted abstract
Preterm delivery increases the risk of inadequate systemic blood flow and hypotension, and many preterm infants fail to respond to conventional inotrope treatments. If the profile of cardiac adrenoceptor subtypes in the preterm neonate is different to that at term this may contribute to these clinical problems. This study measured mRNA expression of β1, β2, α1A, α2A and α2B-adrenoceptor subtypes by real time PCR in term (113d), preterm (91d) and preterm piglets (91d) exposed to maternal glucocorticoid treatment. Abundance of β-adrenoceptor binding sites in the left ventricle was measured using saturation binding assays. Relative abundance of β1-adrenoceptor mRNA in untreated preterm hearts was ~50% of term abundance in both left and right ventricles (P<0.001). Trends in receptor binding site density measurements supported this observation (P = 0.07). Glucocorticoid exposure increased β1-adrenoceptor mRNA levels in the right ventricle of preterm hearts (P = 0.008) but did not alter expression in the left ventricle (P>0.1). Relative abundance of α1A-adrenoceptor mRNA was the same in preterm and term piglet hearts (P = >0.1) but was reduced by maternal glucocorticoid treatment (P<0.01); α2A-adrenoceptor mRNA abundance was higher in untreated and glucocorticoid exposed preterm piglet hearts than in term piglets (P<0.001). There was no difference between male and female piglets in mRNA abundance of any of the genes studied. In conclusion, there is reduced mRNA abundance of β1-adrenoceptors in the preterm pig heart. If this lower expression of β-adrenoceptors occurs in human preterm infants, it could explain their poor cardiovascular function and their frequent failure to respond to commonly used inotropes.
Keyword Multidisciplinary Sciences
Science & Technology - Other Topics
MULTIDISCIPLINARY SCIENCES
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID 5696351
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: UQ Centre for Clinical Research Publications
Official 2015 Collection
 
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Created: Thu, 27 Mar 2014, 23:18:39 EST by Dr Barbara Lingwood on behalf of UQ Centre for Clinical Research