title: Circulating levels of collagen type I degradation marker depend on the type of atrial fibrillation.
abstract: OBJECTIVE
  To investigate the hypothesis that circulating levels of collagen type I degradation or synthesis markers are associated with the presence and pattern of atrial fibrillation (AF).
  
  
  RESULTS
  We assessed the serum concentrations of amino-terminal propeptide of procollagen type I (PINP) and of carboxy-terminal telopeptide of collagen type I (CITP), indexes of collagen type I synthesis and degradation, respectively, in 98 paroxysmal AF (PAF) patients (65 +/- 14 years, 62 men), in 80 persistent AF (PsAF) patients (73 +/- 8 years, 32 men), in 114 permanent AF (PmAF) patients (73 +/- 10 years, 54 men), and in 180 patients in sinus rhythm (SR) (66 +/- 13 years, 88 men) who represented a control group. Serum CITP levels were higher (P < 0.001) in AF patients [0.41 ng/mL, 95% confidence interval (CI) 0.38-0.44] when compared with SR patients (0.29 ng/mL, 95% CI 0.26-0.33) and were significantly different between the three AF pattern groups (P < 0.001). Patients with PAF (0.31 ng/mL, 95% CI 0.26-0.36) had lower CITP levels when compared with patients with PsAF (0.41 ng/mL, 95% CI 0.34-0.47) (P = 0.006), as well as with PmAF patients (0.49 ng/mL 95% CI, 0.43-0.56) (P < 0.001). Levels of CITP tended to be lower (P = 0.219) in PsAF patients when compared with sustained AF patients. No differences were found in PINP levels between AF and SR study groups (P = 0.637) as well as between the three AF pattern groups (P = 0.301).
  
  
  CONCLUSIONS
  In the clinical setting, circulating levels of collagen type I degradation marker are associated with both type and duration of AF. Further studies are needed to evaluate the clinical use of serum concentrations of CITP as a potential diagnostic, prognostic, and therapeutic target in patients with AF.
authors.affiliation: University Cardiology Department, Democritus University of Thrace, Voulgaroktonou 23, 68100 Alexandroupolis, Evros, Greece. dtziakas@med.duth.gr
authors.forename: Dimitrios N
authors.initials: DN
authors.lastname: Tziakas
authors.forename: Georgios K
authors.initials: GK
authors.lastname: Chalikias
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Papanas
authors.forename: Dimitrios A
authors.initials: DA
authors.lastname: Stakos
authors.forename: Sofia V
authors.initials: SV
authors.lastname: Chatzikyriakou
authors.forename: Efstratios
authors.initials: E
authors.lastname: Maltezos
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood* / Q000145:classification / Q000175:diagnosis*; D015415:Biomarkers; D024042:Collagen Type I / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood*; D011347:Procollagen / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide