Down-regulation of sarcolipin mRNA expression in chronic atrial fibrillation

• Published in: European journal of clinical investigation Vol. 34; no. 11; pp. 723 - 730
• Main Authors: Uemura, N., Ohkusa, T., Hamano, K., Nakagome, M., Hori, H., Shimizu, M., Matsuzaki, M., Mochizuki, S., Minamisawa, S., Ishikawa, Y.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-11-2004; Blackwell; Blackwell Publishing Ltd
• Subjects: Adult; Aged; Arrhythmia; Atrial Fibrillation - etiology; Atrial Fibrillation - genetics; Biological and medical sciences; calcium; Calcium-Binding Proteins - genetics; Calsequestrin - genetics; Cardiac dysrhythmias; Cardiology. Vascular system; Chronic Disease; Down-Regulation - genetics; electrical remodelling; Female; gene expression; Gene Expression - genetics; General aspects; Heart; Heart Atria - metabolism; Humans; Male; Medical sciences; Middle Aged; Mitral Valve Insufficiency - complications; Mitral Valve Insufficiency - genetics; Mitral Valve Stenosis - complications; Mitral Valve Stenosis - genetics; Muscle Proteins - genetics; Myocardium - metabolism; Proteolipids - genetics; RNA, Messenger - analysis; Sodium-Calcium Exchanger - genetics; Calcium; Arrhythmia; Atrial fibrillation; Cardiovascular disease; electrical remodelling; Gene expression; Inorganic element; Excitability disorder; Is Arrhythmia; Medicine; Chronic; Regulation(control); Messenger RNA; Heart disease; Regulation
• ISSN: 0014-2972; 1365-2362
• DOI: 10.1111/j.1365-2362.2004.01422.x

Background  Abnormal intracellular Ca2+ homeostasis is an important modulator of chronic atrial fibrillation. Sarcolipin, a homologue of phospholamban, is specifically expressed in the atria, and may play an important role in modulating intracellular Ca2+ homeostasis in the atria. The aim of this study was to investigate the expression of sarcolipin mRNA in the atrial myocardium of patients with chronic atrial fibrillation.
Methods  We analyzed the expression of sarcolipin, phospholamban, cardiac calsequestrin and sodium calcium exchanger mRNAs in the right atrial myocardium from nine patients with mitral valvular disease with atrial fibrillation (MVD/AF), nine patients with MVD who had normal sinus rhythm (MVD/NSR), and 10 control patients with normal sinus rhythm who received open heart surgery (controls). The expression of mRNA was measured using the ABI PRISM 7700 Sequence Detection System (Applied Biosystems, Foster City, CA).
Results  Relative expression levels of sarcolipin mRNA were significantly lower in MVD/AF (0·60 ± 0·11) than in either MVD/NSR (1·28 ± 0·17, P < 0·01) or controls (1·10 ± 0·10, P < 0·05). The expression levels of sarcolipin mRNA were significantly lower in the group with high values for right atrial pressure. The expression levels of phospholamban, cardiac calsequestrin and sodium calcium exchanger mRNAs were comparable among all three groups.
Conclusions  Chronic electrical and mechanical overload decreased the expression of sarcolipin mRNA in the right atrial myocardium in patients with chronic atrial fibrillation. Down‐regulation of sarcolipin mRNA may be part of atrial fibrillation‐induced atrial remodelling.