Document Detail


Downregulation of connexin40 and increased prevalence of atrial arrhythmias in transgenic mice with cardiac-restricted overexpression of tumor necrosis factor.
MedLine Citation:
PMID:  17122196     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Atrial arrhythmias, primarily atrial fibrillation, have been independently associated with structural remodeling and with inflammation. We hypothesized that sustained inflammatory signaling by tumor necrosis factor (TNF) would lead to alterations both in underlying atrial myocardial structure and in atrial electrical conduction. We performed ECG recording, intracardiac electrophysiology studies, epicardial mapping, and connexin immunohistochemical analyses on transgenic mice with targeted overexpression of TNF in the cardiac compartment (MHCsTNF) and on wild-type (WT) control mice (age 8-16 wk). Atrial and ventricular conduction abnormalities were always evident on ECG in MHCsTNF mice, including a shortened atrioventricular interval with a wide QRS duration secondary to junctional rhythm. Supraventricular arrhythmias were observed in five of eight MHCsTNF mice, whereas none of the mice demonstrated ventricular arrhythmias. No arrhythmias were observed in WT mice. Left ventricular conduction velocity during apical pacing was similar between the two mouse groups. Connexin40 was significantly downregulated in MHCsTNF mice. In contrast, connexin43 density was not significantly altered in MHCsTNF mice, but rather dispersed away from the intercalated disks. In conclusion, sustained inflammatory signaling contributed to atrial structural remodeling and downregulation of connexin40 that was associated with an increased prevalence of atrial arrhythmias.
Authors:
Sam E Sawaya; Yadavendra S Rajawat; Tapan G Rami; Gabor Szalai; Robert L Price; Natarajan Sivasubramanian; Douglas L Mann; Dirar S Khoury
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-11-22
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  292     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-03-06     Completed Date:  2007-04-26     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1561-7     Citation Subset:  IM    
Affiliation:
Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Atrial Fibrillation / physiopathology*
Connexins / genetics*
Electrocardiography
Gene Expression Regulation*
Heart / physiopathology
Mice
Mice, Inbred C57BL
Mice, Inbred ICR
Mice, Transgenic
Tumor Necrosis Factor-alpha / genetics*
Grant Support
ID/Acronym/Agency:
HL-42250-10/10/HL/NHLBI NIH HHS; P50-HL-06H/HL/NHLBI NIH HHS; R01-HL-58081-01/HL/NHLBI NIH HHS; R01-HL-61543-01/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Connexins; 0/Tumor Necrosis Factor-alpha; 0/connexin 40

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