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In the field of ophthalmology, postoperative endophthalmitis (POE) is a serious surgical complication, which may lead to poor visual outcome even after the infection has been controlled. In the study, we develop a sustained drug releasing system loaded with levofloxacin which is expected to be effective against common pathogens responsible for POE for at least 7 days after single application at the end of surgery. The results of study showed that the sol–gel transition temperature of the levofloxacin‐loaded chitosan‐gelatin‐based solution was ~34°C. The gelation time of the developed formulation was ~81 s at 34°C. The results showed that the osmolality of developed hydrogel was 304 mOsm/L. The in vitro drug release studies revealed that levofloxacin release from the developed hydrogel displayed a sustained‐release profile. The long‐term antibacterial property of the developed hydrogel has been demonstrated. The biocompatibility of the developed hydrogel was evaluated in vitro. These results suggest that the levofloxacin‐containing hydrogel could be applied to ocular surface at the end of ophthalmic surgery, without the risks of intracameral injection of antibiotics. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:8–13, 2020. [ABSTRACT FROM AUTHOR]

Introduction: Glaucoma is a vision-threatening disease associated with accelerated aging of trabecular meshwork (TM) which results in elevated intraocular pressure (IOP). Increased oxidative stress in TM plays an important role in cellular molecular damage which leads to senescence. Autophagy is an intracellular lysosomal degradation process which is activated when cells are under stressful condition, and emerging studies have demonstrated increased expression of modulators of apoptosis and expression of autophagic cascade in ex-vivo TM specimens or cultured TM cells under oxidative stress. Recently, studies have shown neuroprotective and IOP-lowering effects after transplanting mesenchymal stem cells (MSCs) or injecting condition medium (CM) of MSCs into ocular hypertension animal models. However, knowledge of the underlying mechanism accounting for these effects is limited. Using condition medium (CM) from human bone marrow-derived mesenchymal stem cells (BM-MSCs), we investigated the effects of the CM derived from BM-MSCs on TM autophagy and apoptosis., Methods: H 2 O 2 was added to culture medium of human TM cells to mimic oxidative damage in glaucomatous eyes, and the autophagic and anti-apoptotic effects of BM-MSCs-derived CM was explored on the oxidatively damaged cells. Mitochondrial ROS production was examined by MitoSOX™, apoptosis was evaluated using terminal deoxynucleotidyl transferase (dUTP) nick end labeling (TUNEL) staining, and the expression of proteins involved in autophagy as well as extracellular matrix was investigated via Western blot., Results: There were no significant differences in TM cell viability when the cells were treated with different concentrations of CM in the absence of oxidative stress. Cell viability was significantly higher in oxidatively damaged TM cells treated with 1X or 5X CM compared to untreated TM cells under oxidative stress. The mitochondrial ROS level significantly increased with oxidative stress, which was mitigated in the CM treatment groups. DNA fragmentation significantly decreased in oxidatively stressed TM cells after treatment with CM. LCB3 II/LCB3 I was significantly elevated in the oxidative stress group compared to the control group and was significantly decreased in the CM treatment groups. Expression of fibronectin was not significantly different among the groups., Conclusion: The CM derived from human BM-MSCs has the capacity to rescue oxidatively damaged human TM cells associated with decreased autophagy and apoptosis. The BM-MSCs CM has potential for slowing down age- and disease-related degeneration of TM in patients with glaucoma, facilitating success in the control of IOP., Competing Interests: None., (© 2022 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.)

Staphylococcus species are responsible for most cases of post-operative endophthalmitis. Topical ocular drug was applied for post-operative infection prevention, but the way of delivery encounters many challenges in terms of patient's compliance, drug efficacy, and drug penetration. We used the levofloxacin-loaded chitosan/gelatin/β-glycerophosphate hydrogel sustained releasing system with good in vitro anti-bacterial efficacy and biocompatibility, which we had previously designed, for ex vivo keratitis model to test the preclinical drug efficacy and to determine drug level in the anterior chamber of the eye. The result showed that the ex-vivo corneal keratitis model with S. aureus infection revealed mild opacity over the central cornea with stromal infiltrate, but without obvious stromal infiltration post levofloxacin-loaded hydrogel treatment after 24 h of infection. Quantification of viable bacteria showed a significant anti-bacterial activity. The histological evidence also showed no visible S. aureus after levofloxacin-loaded hydrogel treatment, with a significant anti-inflammatory effect. We also examined the drug concentration in the aqueous humor 24 h after instilling one drop of the levofloxacin-loaded hydrogel. The concentration achieved to a desired drug level. These results suggested that by the ex-vivo model, levofloxacin-loaded hydrogel can be applied for treatment in post-operative endophthalmitis or keratitis after the ophthalmic surgery., Competing Interests: The authors declare no conflict of interest., (© 2021 Published by Elsevier Ltd.)