A novel ophthalmic latanoprost 0.005% nanoemulsion: a cytotoxicity study

Tafluprost promotes axon regeneration after optic nerve crush via Zn2+-mTOR pathway

PURPOSE

To investigate whether Tafluprost could promote optic nerve regeneration in mice after optic nerve crush (ONC) and determine the underlying molecular mechanism.

METHODS

Tafluprost was injected into the vitreous body immediately after ONC. The level of Zn2+ in the inner plexiform layer (IPL) of the retina was stained using autometallography (AMG). The number of survival retinal ganglion cells (RGCs) was determined via dual staining with RGC markers Tuj1 and RBPMS. Individual axons that regenerated to 0.25, 0.5, 0.75 and 1 mm were manually counted in the whole-mount optic nerve labeled by cholera toxin B fragment (CTB). Immunofluorescence and Western blot were performed to detect protein expression levels. Pattern electroretinogram was used to evaluate RGCs function.

RESULTS

Tafluprost promoted RGC survival in a dose-dependent manner with an optimal concentration of 1 μM. Tafluprost significantly decreased ZnT-3 expression and Zn2+ accumulation in the IPL of retina. Tafluprost stimulated intense axonal regeneration and maintained RGCs function compared to control. Mechanistically, Tafluprost and Zn2+ elimination treatment (TPEN or ZnT-3 deletion) can activate the mTOR pathway with an improved percentage of pS6+ RGCs in the retina. However, rapamycin, a specific inhibitor of the mTOR1, inhibited the activation of the mTOR pathway and abolished the regenerative effect mediated by Tafluprost. Tafluprost also inhibited the upregulation of p62, LC3 and Beclin-1, attenuated the overactivation of microglia/macrophages and downregulated the expression of TNFα and IL-1β.

CONCLUSIONS

Our results suggest that Tafluprost promoted axon regeneration via regulation of the Zn2+-mTOR pathway, and provide novel research directions for glaucomatous optic nerve injury mechanisms.

Ocular Surface Evaluation after Switch from Latanoprost 0.005% to Latanoprostene Bunod 0.024

Aim and background

To evaluate the ocular surface of patients treated with latanoprost (LT) 0.005% who switched to latanoprostene bunod (LBN) 0.024%.

Materials and methods

A prospective and nonrandomized clinical study of a case series was performed, including patients with chronic open-angle glaucoma who were on previous LT-only treatment and, after a washout period, switched to LBN, with a 3-month follow-up. The main parameter to be evaluated was the ocular surface disease index (OSDI) test. In addition, best-corrected visual acuity (BCVA), intraocular pressure (IOP), biomicroscopic aspect of the ocular surface, measuring tear breakup time, fluorescein staining (grading performed on Oxford scale) and Schirmer I test were evaluated.

Results

A total of 36 patients (72 eyes) were included, 21 women (58.3%) and 15 men (41.7%, with a mean age of 65.6 ± 10.9 years (37-86). The initial OSDI score was 17.8 ± 12.1 and improved to 11.1 ± 10.5 (p < 0.01). From the data evaluated at biomicroscopy, an improvement was observed in the Oxford scale from 0.6 ± 0.7 to 0.2 ± 0.8 (p: 0.01), but no statistically significant changes were observed in the break-up time (BUT) and Schirmer. BCVA remained stable, as did IOP, which was initially 13.4 ± 2.1 mm Hg and, after performing the LBN treatment change, went to 13.1 ± 1.7 mm Hg.

Conclusion

After the change of treatment from LT 0.005% to LBN 0.024%, the patients had an improvement in the ocular surface, maintaining control of their IOP. The need to investigate possible beneficial mechanisms on the ocular surface in glaucoma patients treated with LBN, potentially related to nitric oxide, is raised.

Clinical significance

Patients treated with LT 0.005% who switched to LBN 0.024% had an improvement in ocular surface symptoms and signs, keeping IOP under control.Latanoprostene bunod (LBN) 0.024% may have beneficial effects on the ocular surface, which should be further studied.

How to cite this article

Zanutigh V, Galetto L, Valvecchia F, et al. Ocular Surface Evaluation after Switch from Latanoprost 0.005% to Latanoprostene Bunod 0.024%. J Curr Glaucoma Pract 2023;17(4):205-209.

Development of an ophthalmic formulation with a postbiotic of Lactiplantibacillus plantarum CRL 759

The term postbiotics has acquired great interest in recent years. Numerous studies have shown a potential beneficial effect of its use in many inflammatory pathologies. However, it has not been much explored in ocular inflammatory diseases. The aims of this study were to develop and characterise an ophthalmic formulation with a postbiotic of Lactiplantibacillus plantarum CRL 759, and to evaluate its anti-inflammatory actions on murine macrophage stimulated with lipopolysaccharides (LPS) in vitro. First, we evaluated the ability of L. plantarum CRL 759 to generate a supernatant with anti-inflammatory property using different buffers. Then, we studied the stability at different temperatures and storage times of the generated postbiotic. In vitro assays showed that incubation of L. plantarum CRL 759 in modified phosphate buffer according to Sorensen (called POF-759), generated a supernatant that significantly reduced the production of interleukin-6, tumour necrosis factor-α, and nitric oxide by RAW 264.7 cells stimulated with LPS. Furthermore, POF-759 maintained its anti-inflammatory activity at room temperature, 4 and -20 °C, up to 30 days of storage. From the studies reported here, a postbiotic product with anti-inflammatory properties and optimal characteristics for the formulation of eye drops was obtained.

Aqueous Prostaglandin Eye Drop Formulations

Glaucoma is one of the leading causes of irreversible blindness worldwide. It is characterized by progressive optic neuropathy in association with damage to the optic nerve head and, subsequently, visual loss if it is left untreated. Among the drug classes used for the long-term treatment of open-angle glaucoma, prostaglandin analogues (PGAs) are the first-line treatment and are available as marketed eye drop formulations for intraocular pressure (IOP) reduction by increasing the trabecular and uveoscleral outflow. PGAs have low aqueous solubility and are very unstable (i.e., hydrolysis) in aqueous solutions, which may hamper their ocular bioavailability and decrease their chemical stability. Additionally, treatment with PGA in conventional eye drops is associated with adverse effects, such as conjunctival hyperemia and trichiasis. It has been a very challenging for formulation scientists to develop stable aqueous eye drop formulations that increase the PGAs' solubility and enhance their therapeutic efficacy while simultaneously lowering their ocular side effects. Here the physiochemical properties and chemical stabilities of the commercially available PGAs are reviewed, and the compositions of their eye drop formulations are discussed. Furthermore, the novel PGA formulations for glaucoma treatment are reviewed.