Controlled delivery of 5-chlorouracil using poly(ortho esters) in filtering surgery for glaucoma.
OBJECTIVE
To evaluate the antimitotic and toxic effects of 5-chlorouracil (5-CU) and 5-fluorouracil (5-FU) and study their potential to delay filtering bleb closure in the rabbit eye when released by poly(ortho esters) (POE).


METHODS
Rabbit Tenon fibroblasts and human conjunctival cells were incubated with various 5-CU and 5-FU concentrations. Antiproliferative effects and toxicity were evaluated at 24 and 72 hours by monotetrazolium, neutral red, and Hoechst tests and cell counting. Mechanisms of cell death were evaluated using TUNEL assay, annexin V binding, immunohistochemistry for anti-apoptosis-inducing factor (AIF) and LEI/L-DNase II. Trabeculectomy was performed in pigmented rabbits. Two hundred microliters of POE loaded with 1% wt/wt 5-FU or 5-CU was injected into the subconjunctival space after surgery. Intraocular pressure (IOP) and bleb persistence were monitored for 150 days.


RESULTS
In vitro, 5-FU showed a higher antiproliferative effect and a more toxic effect than 5-CU. 5-FU induced cell necrosis, whereas 5-CU induced mostly apoptosis. The apoptosis induced by 5-CU was driven through a non-caspase-dependent pathway involving AIF and LEI/L-DNase II. In vivo, at 34 days after surgery, the mean IOP in the POE/5-CU-treated group was 83% of the baseline level and only 40% in the POE/5-FU-treated group. At 100 days after surgery, IOP was still decreased in the POE/5-CU group when compared with the controls and still inferior to the preoperative value. The mean long-term IOP, with all time points considered, was significantly (P < 0.0001) decreased in the POE/5-CU-treated group (6.0 +/- 2.4 mm Hg) when compared with both control groups, the trabeculectomy alone group (7.6 +/- 2.9 mm Hg), and the POE alone group (7.5 +/- 2.6 mm Hg). Histologic analysis showed evidence of functioning blebs in the POE-5-CU-treated eyes along with a preserved structure of the conjunctiva epithelium.


CONCLUSIONS
The slow release of 5-CU from POE has a longstanding effect on the decrease of IOP after glaucoma-filtering surgery in the rabbit eye. Thus, the slow release of POE/5-CU may be beneficial for the prevention of bleb closure in patients who undergo complicated trabeculectomy.
Polak
Marianne Berdugo
MB
Inserm UMRS 872 Team 17, Centre de Recherche des Cordeliers, Paris, France.
Valamanesh
Fatemeh
F
Felt
Olivia
O
Torriglia
Alicia
A
Jeanny
Jean-Claude
JC
Bourges
Jean-Louis
JL
Rat
Patrice
P
Thomas-Doyle
Aoife
A
BenEzra
David
D
Gurny
Robert
R
Behar-Cohen
Francine
F
D000818:Animals; D050256:Antimitotic Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D017209:Apoptosis; D001768:Blister / Q000503:physiopathology; D016923:Cell Death; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002843:Chromatin / Q000187:drug effects; D003228:Conjunctiva / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D016503:Drug Delivery Systems; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D018463:Filtering Surgery / Q000379:methods*; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D005901:Glaucoma / Q000601:surgery*; D006801:Humans; D007150:Immunohistochemistry; D007267:Injections; D007429:Intraocular Pressure / Q000187:drug effects; D009336:Necrosis; D011108:Polymers; D011817:Rabbits; D014130:Trabeculectomy; D014498:Uracil / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use
D050256:Antimitotic Agents; D002843:Chromatin; D011108:Polymers; C401107:poly(ortho ester); D014498:Uracil; C010889:5-chlorouracil; D005472:Fluorouracil