Retinal Toxicity of Intravitreal Granulocyte Colony-Stimulating Factor in Rabbit Eyes

Intravitreal Injection Of The Granulocyte-Colony Stimulating Factor For The Treatment Of Non-Arteritic Anterior Ischemic Optic Neuropathy: A Pilot Study

Purpose To investigate the efficacy of intravitreal injection of granulocyte colony-stimulating factor (G-CSF) for the treatment of non-arteritic anterior ischemic optic neuropathy (NAION).Methods: Patients with acute NAION were enrolled in this prospective interventional case series. They received an intravitreal injection of 60 micrograms in 0.1 ml of G-CSF within 2 weeks of the onset of the disease. Visual acuity, visual field, intraocular pressure (IOP), corneal endothelial cell density, and peripapillary retinal nerve fiber layer (RNFL) thickness were recorded before injections and 1 week, 1 month, 3 months, 6 months, and one year after the injections. Full-field electroretinography (ERG) was obtained at the baseline, 1 month, and 12 months post- injections.Results: Fourteen eyes of 14 patients entered the study. Best-corrected visual acuity (BCVA) significantly improved in the first month following injections (p = .007), decreased subsequently, and the final BCVA showed no significant improvement (p = .278) compared to the baseline measurements. A significant decrease in RNFL thickness was observed in all quadrants compared to the baseline measurements. Also, no improvement in the visual field parameters was observed. From the toxicity aspect, no significant changes in the corneal endothelial cell density, IOP, and ERG recordings were observed.Conclusion: Intravitreal injection of G-CSF seems to be safe. The effect may last for one month and then decline.

Treatment of experimental autoimmune uveoretinitis with intravitreal injection of infliximab encapsulated in liposomes

AIMS

To evaluate the safety and efficacy of intravitreal injection of liposomes encapsulating infliximab in experimental autoimmune uveoretinitis (EAU) rats.

METHODS

Liposomes containing infliximab were prepared and characterised for mean particle size, entrapment efficiency, polydispersity index (PDI) and zeta potential. In vitro release profile and the stability of infliximab-lip were evaluated. EAU rats were intravitreally injected with saline, infliximab, infliximab-lip or unloaded liposomes. Clinical signs and ocular histological sections were graded. Infliximab concentrations were determined with competitive ELISA. Safety of the intravitreal injections was evaluated by electroretinography (ERG) and histopathological examination. Retinal biodistribution and clearance of rhodamine-conjugated liposomes containing infliximab were evaluated with a laser scanning confocal microscope.

RESULTS

The mean particle size of infliximab liposomes was 351.3±58 nm and entrapment efficiency was 90.65%±2.68%. PDI and zeta potential of infliximab liposomes were 0.386 and -20.8±9.78 mV, respectively. Stability test data showed that the infliximab-lip was stable for 60 days at room temperature. In EAU rats, intravitreal injection of infliximab and infliximab-lip greatly reduced intraocular inflammation determined by clinical scores and histopathological analyses (n=4). The mean concentrations of infliximab decreased quickly in infliximab injection group and were lower than those in infliximab-lip injection group (n=4 eyes, p<0.05 after 3 days post injection). No retinal toxic effects were detected after intravitreal injection of infliximab-lip in ERG (n=4 rats, p>0.05) and histopathological sections compared with normal rats. Confocal microscopy showed that fluorescent liposomes were observed in almost every layer of the retina and remained detectable for >30 days after injection.

CONCLUSIONS

Intravitreal injection of liposomal infliximab can prolong the persistence of the drug in vitreous body and demonstrated a satisfactory safety and significant therapeutic potentials in EAU. The use of biodegradable particles for therapeutic antibody delivery may provide a promising approach for the treatment of ocular diseases.