Changes in collagen HP, LP cross-links, and the HP-to-LP ratio.

Changes in collagen HP (A), LP cross-links (B), and the HP-to-LP ratio (C) in μg/mg dry weight (left side: all data points used for correlation analysis with age; right side: grouped data). HP cross-links density increases with age in the aortic valve. In the pulmonary valve, the HP cross-link density increases from adolescent to adult age. LP cross-link density increases with age in both valves. Only in the adult valves, LP cross-link density is different between the aortic and pulmonary valve. In both valves, the HP-to-LP ratio decreases with age, but particularly between childhood and adolescence. Differences between groups (p<0.05) are indicated by paired symbols. AV: aortic valve, PV: pulmonary valve.