title: Correlation of endothelin-1 concentration in aqueous humor with intraocular pressure in primary open angle and pseudoexfoliation glaucoma.
abstract: OBJECTIVE
  Endothelin-1 (ET-1) has been found in elevated concentrations in the aqueous humor of glaucoma patients. Indirect evidence from animal studies suggests that ET-1 might directly influence intraocular pressure (IOP). The aim of this study was to determine whether ET-1 concentrations in aqueous humor of cataract and glaucoma patients correlate with IOP.
  
  
  METHODS
  Aqueous humor and blood samples from patients with either cataract (control, n = 38), primary open angle glaucoma (POAG, n = 35), or pseudoexfoliation glaucoma (PEXG, n = 21), without other ocular or systemic disease, were collected during routine cataract surgery or trabeculectomy. ET-1 concentration was determined by an ET-1 ELISA kit. IOP was measured preoperatively by standard Goldmann applanation tonometry. All statistical analysis was performed using commercial predictive analytics software.
  
  
  RESULTS
  Both IOP and ET-1 concentration in aqueous humor were significantly increased in POAG (23.4 ± 6.8 mm Hg, 5.9 ± 2.9 pg/mL) and PEXG (24.3 ± 8.8 mm Hg, 7.7 ± 2.1 pg/mL) compared with control (15.0 ± 2.9 mm Hg, 4.3 ± 2.4 pg/mL). No difference was detected for plasma ET-1 concentrations. IOP and ET-1 in the aqueous humor were significantly correlated (R = 0.394, R² = 0.155, P < 0.001), although no correlation was found between IOP and ET-1 in blood plasma or between ET-1 in aqueous humor and ET-1 in plasma.
  
  
  CONCLUSIONS
  In this study, a small but highly significant correlation between IOP and the ET-1 concentration in the aqueous humor was found. Although no causative relationship can be deduced from this, ocular ET-1 effects on IOP control may merit further investigation.
authors.affiliation: Department of Ophthalmology, University Medical Center, Mainz, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Choritz
authors.forename: Maren
authors.initials: M
authors.lastname: Machert
authors.forename: Hagen
authors.initials: H
authors.lastname: Thieme
mesh_terms: D000368:Aged; D001082:Aqueous Humor / Q000737:chemistry*; D002386:Cataract / Q000378:metabolism; D002387:Cataract Extraction; D019332:Endothelin-1 / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D017889:Exfoliation Syndrome / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D005902:Glaucoma, Open-Angle / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D011237:Predictive Value of Tests; D014130:Trabeculectomy
chemical_list: D019332:Endothelin-1