Serum biomarkers of collagen type I synthesis (carboxy-terminal propeptide of procollagen type I, PICP), degradation (carboxy-terminal telopeptide of collagen type I, CITP), and enzymes regulating collagen degradation (matrix metalloproteinases, and type I tissue inhibitor, TIMP-1) were measured in 70 rTOF and 91 control adults. All patients had complete clinical data and received cardiovascular magnetic resonance scans with late gadolinium enhancement (LGE).
Compared to the controls, rTOF patients had higher PICP levels (p < 0.001), PICP:CITP ratios (p < 0.001), and TIMP-1 concentrations (p < 0.001). Increasing PICP levels correlated with higher RV LGE scores (r = 0.427, p < 0.001), lower VO2max (r = ? 0.428, p = 0.002), and larger RV volumes. Furthermore, stepwise multivariate linear regression analysis identified RV end-diastolic volume index > 150 mL/m2 (¦Â = 40.52, p = 0.016), RV LGE score (¦Â = 3.94, p = 0.008), and age (¦Â = ? 1.77, p = 0.011) as independent correlates of circulating PICP levels.
Patients with rTOF exhibited a profibrotic state with excessive collagen type I synthesis and dysregulated degradation. Elevated circulating PICP levels might reflect RV fibrosis, and link to adverse markers of clinical outcome.