Attenuated glial reaction in experimental proliferative vitreoretinopathy treated with liposomal doxorubicin

We investigated the therapeutic effect of liposomal doxorubicin (Lipo-dox) on experimental proliferative vitreoretinopathy (PVR).

The toxicity of Lipo-dox was determined in vitro in cultured rabbit retinal pigment epithelium (RPE) cells by tetrazolium-based (MTT) assay for cell viability performed 48 and 96 hours after treatment, and in vivo by electroretinography and histopathology. The therapeutic effect of intravitreous injection of Lipo-dox was evaluated in a rabbit model of PVR induced by injection of rabbit RPE cells after gas compression of the vitreous. The presence of PVR was determined by indirect ophthalmoscopy on days 1, 7, 14, 21, and 28 after injection. Western blot and immunofluorescence studies were performed to evaluate the expression of the glial markers vimentin and glial fibrillary acidic protein (GFAP). A pharmacokinetic study also was performed and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS).

The 50% inhibitory concentrations (IC₅₀) of doxorubicin (Doxo) and Lipo-dox in RPE cells were 0.01-0.1 and 0.1-1.0 μg/mL, respectively. Lipo-dox (10 μg/mL) did not reduce the amplitude reduction in the ERG study or produce obvious retinal toxicity. Lipo-dox still could be detected in the vitreous 7 days after injection. The Lipo-dox (10 μg/mL)-treated eyes showed lower grade PVR than did the untreated eyes. Lipo-dox also decreased the retinal expression levels of vimentin and GFAP.

Lipo-dox can attenuate the severity of experimental PVR, and reduces the glial cell expression of intermediate filaments in PVR retinas. Lipo-dox has a wider safe dosage range and a longer half-life in the vitreous than does primary Doxo.