Myocilin levels in primary open-angle glaucoma and pseudoexfoliation glaucoma human aqueous humor.
OBJECTIVE
To determine the concentration of myocilin in primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEXG) aqueous humor.


METHODS
Aqueous humor was collected during surgery from patients with POAG, PEXG, and elective cataract removal (control). Volume-equivalent aqueous samples were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gradient gels. Quantification of myocilin levels was performed using Western blots probed with 2 independent N-terminal polyclonal anti-myocilin antibodies (AB1 and AB2) followed by densitometry. Myocilin levels in aqueous humor were quantified by plotting the densitometry readings of the aqueous samples against a recombinant myocilin standard curve. Total protein concentration was determined by Bradford protein assay. Transforming growth factor β 2 levels were assessed by enzyme-linked immunosorbent assay.


RESULTS
Myocilin levels are significantly elevated in human POAG aqueous humor when compared with control aqueous humor (AB1: 0.66±0.53 ng/μL vs. 0.23±0.20 ng/μL, P<0.001; AB2: 0.98±0.59 ng/μL vs. 0.65±0.5 ng/μL, P<0.03; mean±SD). Myocilin makes up a larger percent of the total protein in POAG aqueous humor compared with control aqueous (AB1: 0.26±0.20% vs. 0.10±0.20%, P<0.001; AB2: 0.43±0.32% vs. 0.28±0.18%, P<0.05). In contrast to POAG, myocilin levels were not elevated in PEXG aqueous humor when compared with control aqueous humor. No correlation between myocilin and transforming growth factor β 2 levels was observed.


CONCLUSIONS
Myocilin is elevated in POAG, but not in PEXG aqueous humor.
Howell
Kyle G
KG
Department of Ophthalmology, Mayo Clinic, Rochester, MN 55905, USA.
Vrabel
Anne M
AM
Chowdhury
Uttio Roy
UR
Stamer
William Daniel
WD
Fautsch
Michael P
MP
D000368:Aged; D000369:Aged, 80 and over; D001082:Aqueous Humor / Q000378:metabolism*; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D017889:Exfoliation Syndrome / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053781:Transforming Growth Factor beta2 / Q000378:metabolism; D000099179:Myocilin
D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D053781:Transforming Growth Factor beta2; D000099179:Myocilin