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Structural remodelling of the sinoatrial node in obese old rats

During ageing, the function of sinoatrial node (SAN), the pacemaker of the heart, declines, and the incidence of sick sinus syndrome increases markedly. The aim of the study was to investigate structural and functional remodelling of the SAN during ageing. Rats, 3 and 24 months old (equivalent to yo...

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Autores principales: Yanni, J., Tellez, J.O., Sutyagin, P.V., Boyett, M.R., Dobrzynski, H.
Formato: Texto
Lenguaje:English
Publicado: Academic Press 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2845824/
https://www.ncbi.nlm.nih.gov/pubmed/19729016
http://dx.doi.org/10.1016/j.yjmcc.2009.08.023
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author Yanni, J.
Tellez, J.O.
Sutyagin, P.V.
Boyett, M.R.
Dobrzynski, H.
author_facet Yanni, J.
Tellez, J.O.
Sutyagin, P.V.
Boyett, M.R.
Dobrzynski, H.
author_sort Yanni, J.
collection PubMed
description During ageing, the function of sinoatrial node (SAN), the pacemaker of the heart, declines, and the incidence of sick sinus syndrome increases markedly. The aim of the study was to investigate structural and functional remodelling of the SAN during ageing. Rats, 3 and 24 months old (equivalent to young adult and ∼ 69-year-old humans), were studied. Extracellular potential recording from right atrial preparations showed that (as expected) the intrinsic heart rate was slower in the old animals. It also showed a shift of the leading pacemaker site towards the inferior vena cava in the old animals. Consistent with this, intracellular potential recording showed that slow pacemaker action potentials were more widespread and extended further towards the inferior vena cava in old animals. Immunohistochemistry demonstrated that SAN tissue expressing HCN4, but lacking the expression of Na(v)1.5 (lack of Na(v)1.5 explains why pacemaker action potential is slow), was also more widespread and extended further towards the inferior vena cava in the old animals. Immunolabelling of caveolin3 (expressed in cell membrane of cardiac myocytes) demonstrated that there was a hypertrophy of the SAN cells in the old animals. Histology, quantitative PCR, and immunohistochemistry revealed evidence of a substantial age-dependent remodelling of the extracellular matrix (e.g. ∼ 79% downregulation of genes responsible for collagens 1 and 3 and ∼ 52% downregulation of gene responsible for elastin). It is concluded that the age- (and/or obesity-) dependent decline in SAN function is associated with a structural remodelling of the SAN: an enlargement of the SAN, a hypertrophy of the SAN cells, and a remodelling of the extracellular matrix.
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spelling pubmed-28458242010-03-31 Structural remodelling of the sinoatrial node in obese old rats Yanni, J. Tellez, J.O. Sutyagin, P.V. Boyett, M.R. Dobrzynski, H. J Mol Cell Cardiol Original Article During ageing, the function of sinoatrial node (SAN), the pacemaker of the heart, declines, and the incidence of sick sinus syndrome increases markedly. The aim of the study was to investigate structural and functional remodelling of the SAN during ageing. Rats, 3 and 24 months old (equivalent to young adult and ∼ 69-year-old humans), were studied. Extracellular potential recording from right atrial preparations showed that (as expected) the intrinsic heart rate was slower in the old animals. It also showed a shift of the leading pacemaker site towards the inferior vena cava in the old animals. Consistent with this, intracellular potential recording showed that slow pacemaker action potentials were more widespread and extended further towards the inferior vena cava in old animals. Immunohistochemistry demonstrated that SAN tissue expressing HCN4, but lacking the expression of Na(v)1.5 (lack of Na(v)1.5 explains why pacemaker action potential is slow), was also more widespread and extended further towards the inferior vena cava in the old animals. Immunolabelling of caveolin3 (expressed in cell membrane of cardiac myocytes) demonstrated that there was a hypertrophy of the SAN cells in the old animals. Histology, quantitative PCR, and immunohistochemistry revealed evidence of a substantial age-dependent remodelling of the extracellular matrix (e.g. ∼ 79% downregulation of genes responsible for collagens 1 and 3 and ∼ 52% downregulation of gene responsible for elastin). It is concluded that the age- (and/or obesity-) dependent decline in SAN function is associated with a structural remodelling of the SAN: an enlargement of the SAN, a hypertrophy of the SAN cells, and a remodelling of the extracellular matrix. Academic Press 2010-04 /pmc/articles/PMC2845824/ /pubmed/19729016 http://dx.doi.org/10.1016/j.yjmcc.2009.08.023 Text en © 2010 Elsevier Ltd. https://creativecommons.org/licenses/by/4.0/ Open Access under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) license
spellingShingle Original Article
Yanni, J.
Tellez, J.O.
Sutyagin, P.V.
Boyett, M.R.
Dobrzynski, H.
Structural remodelling of the sinoatrial node in obese old rats
title Structural remodelling of the sinoatrial node in obese old rats
title_full Structural remodelling of the sinoatrial node in obese old rats
title_fullStr Structural remodelling of the sinoatrial node in obese old rats
title_full_unstemmed Structural remodelling of the sinoatrial node in obese old rats
title_short Structural remodelling of the sinoatrial node in obese old rats
title_sort structural remodelling of the sinoatrial node in obese old rats
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2845824/
https://www.ncbi.nlm.nih.gov/pubmed/19729016
http://dx.doi.org/10.1016/j.yjmcc.2009.08.023
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