title: In vitro effects of preserved and unpreserved antiglaucoma drugs on apoptotic marker expression by human trabecular cells.
abstract: BACKGROUND
  The mechanisms of trabecular cell loss in glaucoma patients are poorly understood. In order to determine whether drug-induced apoptosis could be one of the mechanisms by which trabecular cells die in glaucoma, we evaluated the effect of benzalkonium-preserved (BAC+) or preservative-free (BAC-) antiglaucoma medications on apoptotic marker expression by cultured human trabecular meshwork (HTM) cells.
  
  
  METHODS
  Normal and glaucomatous trabecular cell lines were treated for 15 min with antiglaucoma drugs (1/100 and 1/10 dilutions): timolol BAC+ or BAC-, betaxolol BAC+ or BAC-, latanoprost BAC+ or pure BAC. Apo2.7 expression, annexin V binding and DNA content were evaluated by flow cytometry and confocal microscopy.
  
  
  RESULTS
  Results obtained in the two cell lines were similar for all tested drugs and criteria. In a 1/100 dilution, unpreserved beta-blockers had no apoptotic effect, preserved beta-blockers and latanoprost significantly increased Apo2.7 expression only, while BAC significantly increased all three apoptotic markers. When tested in a 1/10 dilution, all drugs except unpreserved timolol triggered a 2- to 3.5-fold increase in apoptotic features, whereas up to 95% of the cells underwent apoptosis upon treatment with BAC (representing a 9-fold increase over the background level).
  
  
  CONCLUSIONS
  At concentrations higher than those supposed to be found in the aqueous humor after instillation (1/100 dilution), unpreserved beta-blocker exhibited no proapoptotic activity on HTM cells in vitro. Benzalkonium-containing beta-blockers and prostaglandin analogue triggered mild expression of one out of three apoptotic markers, while the pro-apoptotic effect observed with BAC appeared to be largely hindered by active compounds in the preserved eyedrops.
authors: Department of Ophthalmology, Quinze-Vingts Hospital, 28 rue de Charenton, 75012 Paris, France. pascale-hamard@quinze-vingts.fr
authors: Pascale
authors: P
authors: Hamard
authors: Catherine
authors: C
authors: Blondin
authors: Caroline
authors: C
authors: Debbasch
authors: Jean-Michel
authors: JM
authors: Warnet
authors: Christophe
authors: C
authors: Baudouin
authors: Françoise
authors: F
authors: Brignole
mesh_terms: D000293:Adolescent; D000368:Aged; D017304:Annexin A5 / Q000378:metabolism; D000959:Antihypertensive Agents / Q000494:pharmacology*; D017209:Apoptosis; D001548:Benzalkonium Compounds / Q000494:pharmacology*; D015784:Betaxolol / Q000494:pharmacology; D015415:Biomarkers / Q000032:analysis*; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D006801:Humans; D000077338:Latanoprost; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology*; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology; D013999:Timolol / Q000494:pharmacology; D014129:Trabecular Meshwork / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
chemical_list: D017304:Annexin A5; D000959:Antihypertensive Agents; D001548:Benzalkonium Compounds; D015415:Biomarkers; D008565:Membrane Proteins; D011310:Preservatives, Pharmaceutical; D011461:Prostaglandins F, Synthetic; C102086:antigen 7A6; D000077338:Latanoprost; D013999:Timolol; D004247:DNA; D015784:Betaxolol