Comparison of Prednisolone Acetate and Loteprednol Etabonate for the Treatment of Benzalkonium Chloride-Induced Dry Eye Syndrome in Rats

Calcitriol inhibits apoptosis via activation of autophagy in hyperosmotic stress stimulated corneal epithelial cells in vivo and in vitro

BACKGROUND

Previously, calcitriol has been demonstrated as a potential therapeutic agent for dry eye, whilst its role on corneal epithelium death remains unclear. This study aims to investigate the relationship between apoptosis and autophagy on dry eye related scenario, as well as the effect of calcitriol and its potential mechanism.

METHODS

In vitro, immortalized human corneal epithelial cells (iHCEC) were cultured in hyperosmotic medium with or without various concentrations of calcitriol and other reagents. In vivo, Wistar rats were applied with benzalkonium chloride to induce dry eye. Then rats were topically treated with calcitriol (10^-6 M) for 14 days. Autophagy flux (LC3B-II and SQSTM1/P62) was examined by western blotting or immunostaining. To test cell apoptosis, western blotting for cleaved caspase-3, Annexin V/PI double staining and TUNEL assay were used. CCK-8 assay was performed to detect the cell viability. Small interfering RNA was used to knock down the expression of vitamin D receptor in iHCECs.

RESULTS

Autophagy activation could protect iHCECs against HS induced apoptosis in vitro, and calcitriol was able to augment autophagy flux via VDR signaling, shown as the remarkably elevated expression of LC3B-II, as well as the declined p62 expression. In vivo results further supported the protective role of calcitriol on corneal epithelium apoptosis through promoting autophagy in dry eye rats.

CONCLUSION

The current study indicated that autophagy was an adaptive change of corneal epithelial cells in response to hyperosmotic stress and calcitriol could prevent cells from apoptosis via further activation of autophagy through VDR pathway.

Translational Preclinical Pharmacologic Disease Models for Ophthalmic Drug Development

Preclinical models of human diseases are critical to our understanding of disease etiology, pathology, and progression and enable the development of effective treatments. An ideal model of human disease should capture anatomical features and pathophysiological mechanisms, mimic the progression pattern, and should be amenable to evaluating translational endpoints and treatment approaches. Preclinical animal models have been developed for a variety of human ophthalmological diseases to mirror disease mechanisms, location of the affected region in the eye and severity. These models offer clues to aid in our fundamental understanding of disease pathogenesis and enable progression of new therapies to clinical development by providing an opportunity to gain proof of concept (POC). Here, we review preclinical animal models associated with development of new therapies for diseases of the ocular surface, glaucoma, presbyopia, and retinal diseases, including diabetic retinopathy and age-related macular degeneration (AMD). We have focused on summarizing the models critical to new drug development and described the translational features of the models that contributed to our understanding of disease pathogenesis and establishment of preclinical POC.

Ocular Self-Microemulsifying Drug Delivery System of Prednisolone Improves Therapeutic Effectiveness in the Treatment of Experimental Uveitis

PURPOSE

The purpose of this study was to investigate the self-microemulsifying drug delivery systems (SMEDDS) for ophthalmic delivery of Prednisolone (PDN) to treat uveitis.

MATERIALS AND METHODS

The pseudo-ternary phase diagrams were developed, and various SMEDDS were prepared using Linoleic acid as oil, Cremophore RH 40 as a surfactant, and propylene glycol as a co-surfactant. Physicochemical parameters (globule size, zeta potential, viscosity, and pH) and in vitro release of SMEDDS were studied. The in vivo efficacy of prepared formulations and the marketed drug solution was studied by administering them topically to an endotoxin-induced uveitis rabbit model.

RESULTS

All formulations displayed an average globule size less than 100 nm. The developed SMEDDS exhibited acceptable physicochemical behavior and displayed sustained drug release. In vivo studies in a rabbit eye showed a marked improvement in the anti-inflammatory activity of developed formulation compared with a marketed formulation in a uveitis-induced rabbit eye model.

CONCLUSIONS

The developed SMEDDS are a feasible option to conventional eye drops for its capability to improve bioavailability via its longer precorneal residence time and its capacity to sustain the release of the drug.