title: Atrial fibrosis in heart surgery patients Decreased collagen III/I ratio in postoperative atrial fibrillation.
abstract: In chronic atrial fibrillation, increased expression of angiotensinconverting enzyme (ACE) promotes upregulation of profibrotic proteins. Atrial fibrillation early after cardiac surgery (poAF) is common but unpredictable, and is regarded as a different entity. Therefore, the present study tested whether atrial expression of ACE, osteopontin (OPN), and collagen is elevated in patients with no history of AF but who develop poAF. Thus, 19 patients (66 +/- 9 years) with postoperative sinus rhythm (poSR) were compared to 14 patients (68 +/- 10) who experienced poAF. mRNA and protein expression were determined by RT-PCR and Western blotting. Picrosirius red was used to stain collagen. The medians for ACE, OPN, type I collagen (Col I), and type III collagen (Col III) mRNA and protein expression did not significantly differ between poSR and poAF (U-test). However, the Col III/I protein ratio was significantly lower in patients with poAF (2.62 vs. 1.09; poSR vs. poAF; p < 0.05). Our data suggest that the occurrence of poAF is not dependent on increased ACE and OPN expression, rendering the determination of preoperative OPN plasma levels inadequate to estimate the risk for the occurrence of poAF. Contrarily, a shift in atrial collagen expression levels in favor of Col I is linked to the occurrence of poAF.
authors.affiliation: German Heart Center Munich, Department of Cardiac and Vascular Surgery Technical University of Munich, Lazarettstr. 36, 80636 Munich, Germany. grammer@dhm.mhn.de
authors.forename: Joachim Burkhard
authors.initials: JB
authors.lastname: Grammer
authors.forename: Johannes
authors.initials: J
authors.lastname: Böhm
authors.forename: Annika
authors.initials: A
authors.lastname: Dufour
authors.forename: Matthias
authors.initials: M
authors.lastname: Benz
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Lange
authors.forename: Robert
authors.initials: R
authors.lastname: Bauernschmitt
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology*; D015415:Biomarkers / Q000378:metabolism; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000706:statistics & numerical data; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism*; D024061:Collagen Type III / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005355:Fibrosis; D006325:Heart Atria / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D011183:Postoperative Complications / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D024061:Collagen Type III; D012333:RNA, Messenger