title: Downregulated cardiac annexin VI mRNA and protein levels in chronically fibrillating human atria.
abstract: OBJECTIVE
  We compared the expression and distribution of atrial annexin VI between patients with atrial fibrillation (AF) or sinus rhythm (SR).
  
  
  METHODS
  Atrial appendages were obtained during cardiac surgery from 20 patients with chronic AF and 34 matched controls in SR. The expression and distribution of annexin VI were analyzed using semiquantitative RT-PCR, Western blotting and immunoconfocal microscopy.
  
  
  RESULTS
  In the AF group, compared to SR, the mRNA was reduced to <35% and the protein to <50% in amount (for each atrium, all p < 0.01). Immunoconfocal microscopy confirmed the downregulation of annexin VI protein in AF and demonstrated the colocalization of annexin VI with both Na(+)/Ca(2+) exchangers and L-type Ca(2+) channels in the sarcolemma, but not with ryanodine receptors in the sarcoplasmic reticulum.
  
  
  CONCLUSIONS
  Atrial annexin VI, spatially colocalized with both Na(+)/Ca(2+) exchangers and L-type Ca(2+) channels in the myocyte membrane, is downregulated during chronic AF.
authors.affiliation: Division of Cardiology and Cardiovascular Surgery, Institute of Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Kwo-Chang
authors.initials: KC
authors.lastname: Ueng
authors.forename: Chung-Sheng
authors.initials: CS
authors.lastname: Lin
authors.forename: Hung-I
authors.initials: HI
authors.lastname: Yeh
authors.forename: Yi-Liang
authors.initials: YL
authors.lastname: Wu
authors.forename: Rosa Huang
authors.initials: RH
authors.lastname: Liu
authors.forename: Chin-Feng
authors.initials: CF
authors.lastname: Tsai
authors.forename: Tsung-Po
authors.initials: TP
authors.lastname: Tsai
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000199:Actins / Q000378:metabolism; D000368:Aged; D017317:Annexin A6 / Q000378:metabolism*; D001281:Atrial Fibrillation / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D016009:Chi-Square Distribution; D002908:Chronic Disease; D015897:Comorbidity; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D000199:Actins; D017317:Annexin A6; D015415:Biomarkers; D012333:RNA, Messenger