Aqueous humor in primary open-angle glaucoma contains an increased level of CD44S.
OBJECTIVE
To determine whether the cell adhesion molecule CD44, the principal receptor of hyaluronan, is altered in the aqueous humor and the anterior segment of patients with primary open-angle glaucoma (POAG).


METHODS
The trabecular meshwork (TM), iris, ciliary body, and sclera of POAG and age-matched control eyes preserved in ethanol were microdissected and subjected to 1% Triton X-100 solubilization at 4 degrees C. Western blot analysis was performed using monoclonal antibodies that recognize either CD44H (hematopoietic; extracellular domain) or CD44S (soluble ectodomain). The concentration of soluble CD44S in aqueous and microdissected tissues was measured by enzyme-linked immunosorbent assay (ELISA).


RESULTS
ELISA of soluble CD44S of aqueous from eyes of patients with POAG indicated that the concentration of soluble CD44S is increased in comparison with that of aqueous from normal eyes (P < 0.0003). Western blot analysis and densitometry of POAG iris and ciliary body revealed a statistically significant increase in the Triton X-100 extraction of CD44H. The predominant increases were in the 180-kDa (P < 0.001) and the 85-kDa (P < 0.001) forms. ELISA of soluble CD44S indicated that the concentration is statistically decreased in iris (P < 0.05), ciliary body (P < 0.001), and TM (P < 0.005) of POAG eyes.


CONCLUSIONS
Increased amounts of soluble CD44S in POAG aqueous and Triton X-100-solubilized CD44H characterized POAG in the iris and ciliary body. These soluble CD44 isoforms may influence the activity of the transmembrane CD44H by acting as inhibitors of CD44H and, thereby, adversely influence the cell survival of TM and retinal ganglion cells in POAG.
Knepper
Paul A
PA
Laboratory for Oculo-Cerebrospinal Investigation, Division of Neurosurgery, Children's Memorial Medical Center, Northwestern University Medical School, Chicago, Illinois 60614, USA. pknepper@nwu.edu
Mayanil
Chandra S K
CS
Goossens
William
W
Wertz
Robert D
RD
Holgren
Cory
C
Ritch
Robert
R
Allingham
R Rand
RR
D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D001082:Aqueous Humor / Q000378:metabolism*; D015153:Blotting, Western; D002924:Ciliary Body / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000378:metabolism*; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D007498:Iris / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012590:Sclera / Q000378:metabolism; D012995:Solubility; D014019:Tissue Donors; D014129:Trabecular Meshwork / Q000378:metabolism
D000911:Antibodies, Monoclonal; D005136:Eye Proteins; D018960:Hyaluronan Receptors