title: Diastolic heart failure: evidence of increased myocardial collagen turnover linked to diastolic dysfunction.
abstract: BACKGROUND
  The pathophysiology of diastolic heart failure (DHF) is poorly understood. One potential explanation is an active fibrotic process that produces increased ventricular stiffness, which compromises filling. The present study investigates collagen metabolism in hypertensive patients in different phases of diastolic function with and without proven DHF.
  
  
  RESULTS
  We studied 86 hypertensive patients divided into groups according to the presence of DHF (32 with, 54 without) and phase of diastolic function (20 with normal function, 38 with impaired relaxation, 10 with pseudonormalization, and 16 with restrictive-like filling). Serum carboxy-terminal, amino-terminal, and carboxy-terminal telopeptide of procollagen type I, amino-terminal propeptide of procollagen type III, matrix metalloproteinases (MMPs; total MMP-1, active MMP-2, and MMP-9), and tissue inhibitor of MMPs levels were assayed by radioimmunoassay and ELISA. Doppler-echocardiographic assessment of diastolic filling was made with measurements of E/A ratio, E-wave deceleration time, and isovolumic relaxation time. Serum carboxy-terminal telopeptide of procollagen type I, carboxy-terminal telopeptide of procollagen type I, amino-terminal propeptide of procollagen type III, MMP-2, and MMP-9 levels (P<0.001 for all, controlled for age and gender) were greater in patients with DHF than in those without. When we controlled for age and gender, levels of serum carboxy-terminal telopeptide of procollagen type I, tissue inhibitor of MMP-1, amino-terminal propeptide of procollagen type III (all P<0.001), carboxy-terminal telopeptide of procollagen type I (P=0.008), and MMP-2 (P=0.03) were greater in more severe phases of diastolic dysfunction. Within phases of diastolic dysfunction, serum carboxy-terminal telopeptide of procollagen type I, amino-terminal propeptide of procollagen type III, MMP-2, and MMP-9 were elevated in those with DHF compared with those without DHF (all P<0.001).
  
  
  CONCLUSIONS
  These data demonstrate serological evidence of an active fibrotic process in DHF, which is more marked in more severe diastolic dysfunction. This observation may help explain the pathophysiology of DHF and may suggest new avenues for diagnostic and therapeutic intervention.
authors.affiliation: Heart Failure Unit, St Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
authors.forename: Ramón
authors.initials: R
authors.lastname: Martos
authors.forename: John
authors.initials: J
authors.lastname: Baugh
authors.forename: Mark
authors.initials: M
authors.lastname: Ledwidge
authors.forename: Christina
authors.initials: C
authors.lastname: O'Loughlin
authors.forename: Carmel
authors.initials: C
authors.lastname: Conlon
authors.forename: Anil
authors.initials: A
authors.lastname: Patle
authors.forename: Seamas C
authors.initials: SC
authors.lastname: Donnelly
authors.forename: Kenneth
authors.initials: K
authors.lastname: McDonald
mesh_terms: D000368:Aged; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D003971:Diastole; D005260:Female; D024022:Fibrillar Collagens / Q000378:metabolism*; D005355:Fibrosis; D006333:Heart Failure / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D019714:Tissue Inhibitor of Metalloproteinases / Q000378:metabolism*
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D024022:Fibrillar Collagens; D019714:Tissue Inhibitor of Metalloproteinases; D020782:Matrix Metalloproteinases