Abstract
Purpose: :
To determine age–related changes of the mature collagen cross–links, hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), and the nonenzymatic collagen cross–link pentosidine (Pen), an advanced glycation end product (AGE), in whole human vitreous.
Methods: :
Human eyes (n = 137; 88 donors) with varying ages (between 4 and 80 yrs; mean 56 yrs) and with no known ophthalmic disorders were obtained from the Cornea Bank (Amsterdam, The Netherlands). Vitreous bodies were almost completely dissected by blunt preparation, but strong retinal and ciliary attachments were carefully cut off. The whole vitreous was freeze–dried to reduce its volume before analysis by high–performance liquid chromatography. Linear regression analyses were performed to study the effect of age on several variables.
Results: :
On aging, the weight of the vitreous (4.38 ± 0.81 g; mean ± standard deviation) declines significantly, while the percentage collagen remains stable (0.72 ± 0.35 %), and HP (62.3 ± 67.8 pmol), LP (66.2 ± 54.2 pmol) and Pen (0.66 ± 0.56 pmol) increase significantly. Furthermore, HP per triple helix (TH; 0.85 ± 0.84), LP per TH (1.25 ± 1.45) and Pen per TH (0.01 ± 0.01) also rise significantly.
Conclusions: :
Our study confirms the increase of Pen found in vitrectomy samples in the whole human vitreous. In general, Pen may play a major role in collagen’s changes resulting in pathological changes. In contrast with vitrectomy samples, a rise in both mature cross–links, HP and LP, are found.
Keywords: vitreous • extracellular matrix