Evaluation of phacoemulsification-induced oxidative stress and damage of cultured human corneal endothelial cells in different solutions using redox fluorometry microscopy

Risk Factors for Corneal Endothelial Decompensation after Penetrating Keratoplasty: A Population-Based Cohort Study

(1) Background: Endothelial decompensation is a common complication after penetrating keratopathy (PK), while the risk factors for endothelial decompensation after PK have not been fully elucidated. Consequently, we aim to investigate the possible risk factors for endothelial decompensation after PK. (2) Methods: This retrospective study was conducted using the National Health Insurance Research Database (NHIRD) of Taiwan. The main outcome was the development of endothelial decompensation after PK surgery. The effects of potential risk factors were compared between the patients with endothelial decompensation and the patients without endothelial decompensation via Cox proportional hazard regression, which produced the adjusted hazard ratio (aHR) and a 95% confidence interval (CI). (3) Results: Overall, 54 patients developed endothelial decompensation after PK surgery, with a ratio of 16.12 percent. The pre-existing type 2 diabetes mellitus (T2DM) (aHR: 1.924, 95% CI: 1.257-2.533, p = 0.0095) and history of cataract surgery (aHR: 1.687, 95% CI: 1.328-2.440, p = 0.0026) were correlated with the development of endothelial decompensation. In the subgroup analysis, the correlation between a history of cataract surgery and post-PK endothelial decompensation was more prominent in patients older than 60 years compared to their younger counterparts (p = 0.0038). (4) Conclusions: Pre-existing T2DM and a history of cataract surgery are associated with a higher incidence of post-PK endothelial decompensation.

Topical Ascorbic Acid Ameliorates Oxidative Stress-Induced Corneal Endothelial Damage via Suppression of Apoptosis and Autophagic Flux Blockage

Compromised pumping function of the corneal endothelium, due to loss of endothelial cells, results in corneal edema and subsequent visual problems. Clinically and experimentally, oxidative stress may cause corneal endothelial decompensation after phacoemulsification. Additionally, in vitro and animal studies have demonstrated the protective effects of intraoperative infusion of ascorbic acid (AA). Here, we established a paraquat-induced cell damage model, in which paraquat induced reactive oxygen species (ROS) production and apoptosis in the B4G12 and ARPE-19 cell lines. We demonstrate that oxidative stress triggered autophagic flux blockage in corneal endothelial cells and that addition of AA ameliorated such oxidative damage. We also demonstrate the downregulation of Akt phosphorylation in response to oxidative stress. Pretreatment with ascorbic acid reduced the downregulation of Akt phosphorylation, while inhibition of the PI3K/Akt pathway attenuated the protective effects of AA. Further, we establish an in vivo rabbit model of corneal endothelial damage, in which an intracameral infusion of paraquat caused corneal opacity. Administration of AA via topical application increased its concentration in the corneal stroma and reduced oxidative stress in the corneal endothelium, thereby promoting corneal clarity. Our findings indicate a perioperative strategy of topical AA administration to prevent oxidative stress-induced damage, particularly for those with vulnerable corneal endothelia.

[Phacoemulsification cataract surgery with different cumulative energy composite parameters in patients with type 2 diabetes mellitus:therapeutic effect and complications]

OBJECTIVE

To evaluate the effect of different cumulative energy composite parameters on the outcomes of phacoemulsification cataract surgery in patients with type 2 diabetes mellitus.

METHODS

A total of 252 patients with cataract (involving 252 eyes) and type 2 diabetes mellitus received phacoemulsification cataract surgery in our hospital between January, 2017 and June, 2019. The patients were divided into group A (150 cases) and group B (102 cases) for cataract phacoemulsification with cumulative energy composite parameters of 8 and 10, respectively, and 90 nondiabetic patients received cataract phacoemulsification with a cumulative energy composite parameters of 10 served as the control. The macular thickness, best corrected visual acuity, visual acuity, and postoperative leakage in the 3 groups were evaluated at 1 week, 1 month, and 3 months after the surgery.

RESULTS

The visual acuity was significantly improved after phacoemulsification better in all the 3 groups. At 3 months after the surgery, the proportions of patients with visual acuity ratio < 0.1 or >1.0, macular thickness, best corrected visual acuity and permeability differed significantly between groups A and B (P < 0.05), but not between group A and the control group (P > 0.05). At 1 month and 3 months after the surgery, the proportion of patients with visual acuity ratio < 0.1 was significantly lower and the rate of visual acuity ratio >1.0 was higher in group A than in group B. At 1 month after the operation, the total leakage rate in group A (31.1%) was higher than that in the control group (21.1%) but comparable with that in group B; at 3 months, the total leakage rates were significantly lower in group A than in group B (10.0% vs 32.4%, P < 0.05), and the leakage resulted mainly from local and diffuse permeation.

CONCLUSIONS

Phacoemulsification can effectively improve the visual acuity of cataract patients especially in non-diabetic patients. A lower cumulative energy composite parameter achieves better outcomes in type 2 diabetic patients with cataract. The macular thickness, local infiltration and diffuse leakage can be used as indicators for assessing visual recovery and stabilization after phacoemulsification.

All-laser bladeless cataract surgery, combining femtosecond and nanosecond lasers: a novel surgical technique

Purpose

To report the safety and efficacy of a novel surgical technique using two lasers in cataract surgery.

Methods

In this contralateral eye report, a 57-year-old female underwent cataract extraction. Two laser devices and a standard phacoemulsification, platform were used to conduct the procedures. First, a femtosecond laser was used to perform the corneal incision, capsulorhexis, and initial lens fragmentation in each eye. Following this, a nanosecond laser was used to enter the 2.8 mm incision, uni-axially, and complete the viscoelastic-divided nucleus fragment emulsification and removal in one eye. Standard phacoemulsification was used in the completion of the other eye. Posterior chamber foldable acrylic intraocular lenses were implanted in both cases. We evaluated perioperative acuity, refraction, keratometry, Scheimpflug tomography, intraocular pressure, endothelial cell counts, and total energy used with each laser in each case.

Results

Corrected distance visual acuity improved from preoperative 20/60 and 20/70 to postoperative 20/20 in both eyes, with 6-month follow-up. In the right eye, the total intraocular energy used was 2 J by the femtosecond laser and 6 J by the phacoemulsification device. In the left eye, the nanosecond laser utilized the same energy of 2 J and the nanosecond laser 2.4 J (80 pulses of 30 mJ each). There were no other differences noted in intraocular pressure or endothelial cell counts.

Conclusion

In this report, we introduce a bladeless all-laser cataract surgery extraction alternative technique, with several potential novel advantages: enhanced incision and capsulorhexis reproducibility, reduction in intraocular energy used, and elimination of the potential of thermal corneal injury.

Rapamycin reduces reactive oxygen species in cultured human corneal endothelial cells

PURPOSE

To investigate the protective effect of rapamycin on oxidative stress-induced cell death of human corneal endothelial cells (HCECs).

METHODS

HCECs were cultured according to previously published methods. With treatment of 0 mM or 5 mM of tert-butyl hydroperoxide (tBHP) with various concentrations (0, 25 and 50 nM) of rapamycin, reactive oxygen species (ROS) production was measured using an oxidation-sensitive fluorescent probe, 2'7'-dichlorofluorescin diacetate (DCFH-DA, USA) methods. Cell viability was assayed by the method of Cell Counting Kit-8 (CCK-8, Wako). The levels of cellular glutathione were also assessed enzymatically with glutathione reductase by using a commercial glutathione (GSH) assay kit (Cayman Chemical, USA).

RESULTS

Rapamycin reduced 2'7'-dihydrodichlorofluorescein oxidation and increased GSH in HCECs. Rapamycin significantly inhibited tBHP-induced ROS production. Cells treated with rapamycin showed higher viability compared to control at 5 mM tBHP. Rapamycin effectively protected HCECs from ROS-induced cell death through increasing intracellular GSH.

CONCLUSION

Our data suggest that rapamycin protects HCECs from oxidative injury-mediated cell death via inhibition of ROS production and enhancement of GSH.