Glycosaminoglycans of the human trabecular meshwork in primary open-angle glaucoma

Paul A. Knepper, William Goossens, Michael Hvizd, Paul F. Palmberg

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Abstract

Purpose. Glycosaminoglycans (GAGs) contribute to the filtration barrier of aqueous outflow through the trabecular meshwork (TM). The purpose of this biochemical study was to identity the type and amount of GAGs in normal and in primary open-angle glaucoma (POAG) TM and adjacent anterior segment structures. Methods. The GAGs of 21 masked individual normal and POAG human TMs, as well as iris, ciliary body, and anterior sclera, were isolated biochemically, identified by selective GAG-degrading enzymes, and quantitated by computer-enhanced densitometry. Results. In 10 normal TMs (8 donors, 65 to 83 years of age), the GAG profile was: hyaluronic acid (0.77 ± 9.26 ng/μg dry-defatted weight ± SEM); chondroitin 4(6-) sulfates and dermatan sulfate, collectively referred to as chondroitin sulfates (1.90 ± 0.13 ng); keratan sulfates (0.33 ± 0.06 ng); heparitin sulfates (2.02 ± 0.52 ng); GAG enzyme- resistant material (0.02 ± 0.01 ng); and total GAGs (5.05 ± 0.70 ng). In 10 POAG TMs (6 donors, 67 to 88 years of age), the GAG profile was: hyaluronic acid (0.18 ± 0.11 ng; P < 0.02, a 77% decrease; 6 of 19 TMs contained no detectable hyaluronic acid); chondroitin sulfates (2.39 ± 0.31 ng); keratan sulfates (0.21 ± 0.06 ng); heparitin sulfates (1.36 ± 0.43 ng); GAG enzyme- resistant material (0.08 ± 0.01 ng; P < 0.021; and total GAGs (4.09 ± 0.33 ng; statistically insignificant). In the POAG iris, hyaluronic acid content was less (82% decrease, P < 0.02), and the chondroitin sulfates content was higher (72% increase, P < 0.02). Similarly, the POAG ciliary body and anterior sclera contained less hyaluronic acid and more chondroitin sulfates. The GAG profile of a 'glaucoma suspect' donor specimen was similar to that of the POAG donor specimen. Conclusions. The data provide the first quantitative biochemical profiles of GAGs of individual normal and POAG TM, and we suggest that a depletion of hyaluronic acid and the accumulation of chondroitin sulfates may increase aqueous outflow resistance in the POAG TM.

Original languageEnglish (US)
Pages (from-to)1360-1367
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Volume37
Issue number7
StatePublished - Jun 1 1996

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Keywords

  • aqueous outflow resistance
  • chondroitin sulfate
  • glaucoma
  • glycosaminoglycans
  • hyaluronic acid
  • trabecular meshwork

ASJC Scopus subject areas

  • Ophthalmology

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