Chondroitin sulfate in normal human plasma is modified depending on the age. Its evaluation in patients with pseudoxanthoma elasticum

Abstract

Plasma chondroitin sulfate (CS) amount and charge density were determined in 45 healthy volunteers (control group), 45 pseudoxanthoma elasticum (PXE)-affected patients and 19 healthy carriers by using fluorophore-assisted carbohydrate electrophoresis (FACE) and HPLC equipped with postcolumn derivatization and fluorescence detection. The mean values of CS amount were 4.9 ± 1.21 for volunteers, 4.7 ± 1.40 for PXE subjects and 4.4 ± 1.44 for the carriers. No significant differences were found for the three human subjects groups. On the contrary, by considering the age of normal volunteers, a significant increase of plasma CS amount was measured. In fact, the volunteers aging from 17 to 40 years (mean 32.1) showed a CS concentration of 4.3 ± 1.30 while the group ranging from 50 to 74 years (mean 56.9) had a value of 5.6 ± 1.16 with a significant increase of + 30.2%. The same significant increase in CS plasma content with increasing age was measured for PXE-affected and healthy carriers group. Extracted plasma CS was evaluated for the main two unsaturated disaccharides, non-sulfated and 4-monosulfated, and the charge density determined. The mean values were 0.54 ± 0.13 for volunteers, 0.60 ± 0.15 for PXE subjects and 0.50 ± 0.15 for the carriers. A significant increase of + 11.1% was found between the PXE patients and healthy human group but no differences were calculated between the control group and the carriers. Furthermore, besides a CS amount, the volunteers aging from 17 to 40 years (mean 32.1) showed a charge density of 0.53 ± 0.14 while the group ranging from 50 to 74 years (mean 56.9) had a value of 0.58 ± 0.17 with a significant increase of + 9.4%. The same trend was measured for the healthy carriers group. The CS charge density of PXE-affected subjects was found to increase significantly more than healthy controls depending on the age. In fact, the PXE patients aging from 10 to 40 years (mean 29.3) showed a charge density of 0.56 ± 0.14 while the group ranging from 50 to 74 years (mean 58.6) had a value of 0.67 ± 0.11 with a significant increase of + 19.6%. Furthermore, the group of PXE-affected subjects ranging from 50 to 74 years (mean 58.6) showed a significant increase of 15.5% in comparison with the group matched for age (mean 56.9) of healthy volunteers.