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Corticosteroids and daunomycin in the prevention of experimental proliferative vitreoretinopathy induced by
1Eye Center, Xijing Hospital, Fourth Military Medical University, Xian, Peoples Republic of China.
Abstract:
An experimental model of proliferative vitreoretinopathy (PVR) induced by macrophages simulates a special form of wound healing process in the eye and mimics the development of PVR from its initial stage. We used this model for the evaluation of drug efficacy in the prevention of PVR. One mg triamcinolone acetonide (TA), 10 micrograms daunomycin-liposome (DL), 5 micrograms free daunomycin (FD) and 0.1 ml saline or empty liposomes (as controls) were injected into the vitreous in four groups of animals (30 or 40 rabbit eyes each) after macrophage injection. Retinal detachment developed in 77.5% of the control eyes on day 28, compared to 13.3% of the TA-treated eyes (P < 0.01), to 33.3% of the eyes treated with DL (P < 0.01), and 50% of the FD-treated eyes (P < 0.05). TA cleared up from the vitreous within 35-63 days (average 45.5 days). The half-time of FD clearance was 145.5 min. Although DL declined rapidly during the first 2 days, there was an average of 0.64 microgram/ml daunomycin in the vitreous on day 14. Transmission electron microscopy showed that FD at a dosage of over 5 micrograms or DL over 20 micrograms was toxic to the retina and that up to 4 mg TA was nontoxic. These results suggest that steroids such as TA, given at the inflammatory stage, can effectively and safely prevent the development of PVR, and that encapsulation in liposomes of cytotoxic agents such as daunomycin can enhance drug efficacy and reduce toxicity. The time course of initiation and development of PVR is important in the selection of particular drugs.
Insights
Triamcinolone acetonide (TA) and liposomal daunomycin (DL) effectively prevent proliferative vitreoretinopathy (PVR) in rabbit eyes. TA demonstrated superior safety and efficacy compared to free daunomycin (FD) in this experimental PVR model.
Area of Science:
- Ophthalmology
- Retinal Diseases
- Pharmacology
Background:
- Proliferative vitreoretinopathy (PVR) is a severe complication following retinal detachment surgery.
- An experimental model using macrophages mimics PVR development, serving as a platform for drug evaluation.
- Understanding PVR's wound healing process is crucial for developing effective preventative treatments.
Purpose of the Study:
- To evaluate the efficacy of triamcinolone acetonide (TA) and daunomycin (free and liposomal) in preventing PVR.
- To assess the safety and pharmacokinetic profiles of these drugs in an experimental PVR model.
- To determine the optimal drug selection based on PVR's temporal progression.
Main Methods:
- An experimental PVR model was induced by macrophage injection in rabbit eyes.
- Groups of rabbit eyes received intravitreal injections of TA, daunomycin-liposome (DL), free daunomycin (FD), or controls.
- Drug efficacy, retinal detachment incidence, drug clearance, and retinal toxicity were assessed.
Main Results:
- TA significantly reduced retinal detachment (13.3%) compared to controls (77.5%).
- DL also showed efficacy (33.3% detachment), while FD had less effect (50% detachment).
- TA was non-toxic at therapeutic doses, whereas FD and DL exhibited retinal toxicity at higher concentrations.
Conclusions:
- Intravitreal triamcinolone acetonide (TA) is a safe and effective agent for preventing PVR during the inflammatory stage.
- Liposomal encapsulation of daunomycin (DL) enhances its efficacy and reduces toxicity compared to free daunomycin (FD).
- Drug selection for PVR prevention should consider the specific timing of the disease's initiation and development.