In vitro effects of preserved and unpreserved antiglaucoma drugs on apoptotic marker expression by human trabecular cells.
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.
Hamard
Pascale
P
Department of Ophthalmology, Quinze-Vingts Hospital, 28 rue de Charenton, 75012 Paris, France. pascale-hamard@quinze-vingts.fr
Blondin
Catherine
C
Debbasch
Caroline
C
Warnet
Jean-Michel
JM
Baudouin
Christophe
C
Brignole
Françoise
F
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
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