Mature Enzymatic Collagen Cross-Links, Hydroxylysylpyridinoline and Lysylpyridinoline, in the Aging Human Vitreous

• Published in: Investigative ophthalmology & visual science 2009-03, Vol.50 (3), p.1041-1046
• Main Authors: Ponsioen, Theodorus L, Deemter, Marielle van, Bank, Rudolf A, Snabel, Johanna M, Zijlstra, Gerrit S, van der Worp, Roelofje J, Hooymans, Johanna M. M, Los, Leonoor I
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Aging - physiology; Amino Acids - metabolism; Biological and medical sciences; Child; Child, Preschool; Chromatography, High Pressure Liquid; Collagen - metabolism; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; Humans; Male; Medical sciences; Middle Aged; Ophthalmology; Organ Size; Vertebrates: nervous system and sense organs; Vitreous Body - metabolism
• ISSN: 0146-0404; 1552-5783; 1552-5783
• DOI: 10.1167/iovs.08-1714

The vitreous body of the human eye undergoes progressive morphologic changes with aging. Since the enzymatic collagen cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are known to be important for the integrity of the collagen matrix, the presence in the vitreous on aging was studied. Vitreous bodies (VBs; n = 143) from 119 donors (age 4-80 years; mean +/- SD, 54.3 +/- 17.0 years) were carefully dissected. After weighing and freeze-drying, all samples were analyzed by high performance liquid chromatography. Left and right eyes of 24 donors were compared and, for age-related phenomena, 119 single eyes were used. Within one donor, no significant differences were found between left and right eyes. On aging, VB wet weight (4.42 +/- 0.84 g) accumulates until 35 years and decreases thereafter. Collagen content (0.30 +/- 0.14 mg), HP per triple helix (TH; 0.55 +/- 0.18), and (HP plus LP)/TH (0.61 +/- 0.19) increase until 50 years followed by a decrease, whereas LP/TH (0.057 +/- 0.018) accumulates until 50 years and remains constant thereafter. The ratio between HP and LP (range, 0.42-31.0; median, 10.0) is constant over time. The accumulation of enzymatic collagen cross-links until 50 years is consistent with collagen maturation and possible collagen synthesis in the human vitreous body. The decline of collagen cross-links after 50 years is consistent with collagen breakdown.