CHANGES IN THE COLLAGENOUS MATRIX OF THE AGING HUMAN LAMINA-CRIBROSA

Aims-The age-related changes in the biochemical composition of the col lagenous matrix of the human lamina cribrosa were investigated. Method s-An age range (3 weeks to 92 years old) of human laminae cribrosae, d issected free of any surrounding structures which contained collagen, were analysed for collagen solubility (n=58) total collagen content (n =46), proportion of collagen types (n=38), and collagen cross linking (n=30), using hydroxyproline analysis, scanning densitometry of peptid es after cyanogen bromide digestion, and high performance liquid chrom atography, respectively. Results-Age-related changes included an incre ase in total collagen and a decrease in the proportion of type III col lagen within the lamina cribrosa. The collagen cross link pyridinoline was present at low levels, but demonstrated no trend with age. An age -related increase was found in pentosidine, an advanced glycation prod uct. Conclusion-These changes in collagen composition imply that the m echanical properties of the lamina cribrosa are altered, resulting in a stiffer, less resilient structure with age. Such alterations in stru cture may contribute to the increased susceptibility of the elderly to axonal damage in chronic open angle glaucoma.