TLR4-Dependent DUOX2 Activation Triggered Oxidative Stress and Promoted HMGB1 Release in Dry Eye

Dry eye disease (DED) is one of the most common ocular surface diseases worldwide. DED has been characterized by excessive accumulation of reactive oxygen species (ROS), following significant corneal epithelial cell death and ocular surface inflammation. However, the key regulatory factor remains unclear. In this study, we tended to explore whether DUOX2 contributed to DED development and the underlying mechanism. Human corneal epithelial (HCE) cells were treated with hyperosmolarity, C57BL/6 mice were injected of subcutaneous scopolamine to imitate DED. Expression of mRNA was investigated by RNA sequencing (RNA-seq) and quantitative real-time PCR (qPCR). Protein changes and distribution of DUOX2, high mobility group box 1 (HMGB1), Toll-like receptor 4 (TLR4), and 4-hydroxynonenal (4-HNE) were evaluated by western blot assays and immunofluorescence. Cell death was assessed by Cell Counting Kit-8 (CCK8), lactate dehydrogenase (LDH) release, and propidium iodide (PI) staining. Cellular ROS levels and mitochondrial membrane potential (MMP) were analyzed by flow cytometry. RNA-seq and western blot assay indicated a significant increase of DUOX2 dependent of TLR4 activation in DED both in vitro and in vivo. Immunofluorescence revealed significant translocation of HMGB1 within corneal epithelial cells under hyperosmolar stress. Interestingly, after ablated DUOX2 expression by siRNA, we found a remarkable decrease of ROS level and recovered MMP in HCE cells. Moreover, knockdown of DUOX2 greatly inhibited HMGB1 release, protected cell viability and abolished inflammatory activation. Taken together, our data here suggest that upregulation of DUOX2 plays a crucial role in ROS production, thereafter, induce HMGB1 release and cell death, which triggers ocular surface inflammation in DED.

Is there a role for tapered topical dose steroidal treatment for dry eye disease? A randomized, pilot study

Purpose: To evaluate the effect of tapered doses of loteprednol-etabonate in dry eye disease patients. Materials and methods: Dry eye and treatment outcomes were assessed by Schirmer I test, tear BUT, lissamine green conjunctival staining, fluorescein corneal staining, and HLA-DR expression on conjunctival cells. Patients received either loteprednol-etabonate 0.5% twice daily for 14 days tapered to once daily for 14 days, and then twice weekly for 28 days ( n = 10), or NaCl 0.9%. Results: A significant decrease of ocular surface inflammation and improvement of symptoms was recorded in the study group compared with controls at days 14 and 56. Change from baseline in HLA-DR expression in CD45+ conjunctival cells was significantly higher in treated patients at day 14. Intraocular pressure and best corrected visual acuity were preserved in all treated eyes. Conclusions: Tapered doses of loteprednol etabonate 0.5% suspension controlled ocular surface inflammation, improving dry eye symptoms.

Bilateral corneal endothelial failure following COVID-19 pneumonia

We describe a patient who developed acute bilateral corneal decompensation following COVID-19 pneumonia and prolonged intensive care unit ventilation. SARS-CoV-2 uses human ACE2 as the receptor for entry with subsequent downregulation of ACE2. ACE2 receptors are found in human ocular surface cells including cornea. Mouse models of ACE2 deficiency result in corneal haze, oedema and ocular surface inflammation due to upregulation of the inflammatory cascades. We therefore hypothesise that the cause of this patient’s corneal decompensation was viral endotheliitis due to direct infection by the SARS-CoV-2 virus.

Prognostic significance of matrix metalloproteinase 9 in COMET operated chronic ocular Stevens-Johnson syndrome

PurposeMolecular pathogenesis underlying persistent ocular surface inflammation in chronic Stevens-Johnson syndrome (SJS) still remains largely unexplored. The present study investigates the expression of matrix metalloproteinase 2 (MMP2), MMP3, MMP9, MMP11 and TIMP1 (tissue inhibittor of matrix metalloproteinase 1) in pannus tissues of chronic ocular SJS undergoing cultivated oral mucosal epithelial transplantation (COMET) and their prognostic relevance.MethodsIn this prospective study, 45 eyes with chronic SJS underwent COMET for visual and anatomical rehabilitation. Preoperative and postoperative clinical parameters were documented. MMP2, MMP3, MMP9, MMP11 and TIMP1 expression were assessed using immunohistochemistry and quantitative real time PCR. Inflammadry MMP9 assay was performed at 1-year follow-up. Kaplan-Meier curves and Cox proportional hazard models were used to correlate protein expression with clinicopathological parameters and COMET graft survival outcomes.ResultsMMP9 and MMP11 positivity was seen in both pannus epithelia (48% and 55%, respectively) and in stromal layer (57% and 33%, respectively) while MMP2 and MMP3 showed only pannus epithelial positivity in 35% and 51% cases, respectively. High MMP9 stromal expression was significantly associated with preoperative corneal keratinisation (p=0.011), conjunctival hyperaemia (p=0.014), symblepharon (p=0.028). High MMP9 and MMP3 epithelial expression were found to be independent risk factors for poor best-corrected visual acuity (BCVA) outcomes post-COMET (p=0.022 and p=0.048). Multivariate analysis revealed MMP9 to be the best prognostic marker (p=0.050).ConclusionOur findings suggest that differential expression of MMPs and TIMP1 is seen in SJS in chronic stage. Emergence of MMP9 as a poor prognostic predictor of BCVA post COMET and postoperative MMP9 immunoassay positivity could be a useful tool in further studies to understand the unresolved ocular surface inflammation seen in SJS.

Ocular surface angiography: from neovessels to neoplasia

The ocular surface vascular system plays a key role in corneal and conjunctival inflammatory, infectious and neoplastic pathology. Angiographic vessel analysis using intravenous dyes and optical coherence tomography technology allow both the quantitative and functional assessment of conjunctival vasculature and corneal neovessels. Based on a thorough understanding of vascular alterations in ocular surface disease, angiographic assessment facilitates the clinical management of corneal neovascularisation, the grading of ocular surface inflammation and the identification of tumour angiogenesis in dysplastic or malignant lesions. This review summarises key aspects of the clinical application of corneal and conjunctival angiography as presented at the 2021 virtual Bowman Club meeting.

Japan: Diagnosis and Management of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis With Severe Ocular Complications

In 2005, the “Japanese Research Committee on Severe Cutaneous Adverse Reaction” (J-SCAR) presented the official “Diagnostic Criteria” for SJS/TEN, and the specific ocular findings are included in these very important criteria. In SJS/TEN cases involving ocular disorder, conjunctivitis often occurs prior to the onset of the high fever. In a Japanese survey, ocular involvement was observed in 77% of the cases, and the incidence of ocular sequelae increased depending on the score of the acute ocular severity findings. Pseudo-membrane formation and epithelial defects are considered to be high-risk signs of ocular sequelae. At the chronic stage, limbal stem cell deficiency, visual disturbance, and severe dryness of the ocular surface are the primary disease characteristics. In 2002, we started performing Cultivated Oral Mucosal Epithelial Transplantation (COMET) for the treatment of severe ocular disorders, including SJS/TEN. As an additional treatment method, we developed a new type of rigid contact lens (CL) that is 13 to 14.0-mm in diameter, known as the “Limbal Rigid Contact Lens (Limbal CL).” Our Limbal Rigid CL greatly enhances the postoperative outcome of COMET. The detection rate of ocular surface bacteria is high in SJS/TEN cases. Thus, appropriate use of topical antibiotics reduces the risk of ocular surface inflammation. Moreover, rebamipide is an ophthalmic solution for dry eye that was developed in Japan, and it also has the effect of suppressing ocular surface inflammation. From disease onset until the chronic stage, the control of inflammation and stem cell loss is key to successfully treating eyes afflicted with SJS/TEN.

PreserFlo MicroShunt® exposure: a case series

Background PreserFlo® MicroShunt (PM) (also known as InnFocus® MicroShunt) is a subconjunctival stent implanted ab externo via a minimally invasive surgical procedure. The current indication is progressive, mild to moderate, open angle glaucoma uncontrolled on topical medications. According to the literature, adverse events are rare, mild and transient. Case presentation Two cases of stand-alone PreserFlo MicroShunt® implantation in patients with uncontrolled open-angle glaucoma are reported. Exposure occurred 7 days and 3 months respectively after implantation. These cases shared common features including preexisting blepharitis and the lack of a Tenon’s flap. In both cases, removal of the device was required after several attempts at repair. Conclusions PreserFlo MicroShunt® exposure is a potentially vision-threatening complication because of the risk of endophthalmitis. Potential risk factors include the absence of a Tenon’s flap and pre-existing ocular surface inflammation. Ocular surface inflammation should be detected and treated prior to PM implantation. If a deficiency in Tenon’s capsule is noted intraoperatively, close monitoring should be performed because of the higher risk of PM exposure.

Long-term results of topical 0.02% tacrolimus ointment for refractory ocular surface inflammation in pediatric patients

Background No studies have been reported on the efficacy and safety of long-term (≥12 months) use of topical tacrolimus for refractory ocular surface inflammation in pediatric patients. Methods Medical records of pediatric patients who were prescribed topical 0.02% tacrolimus ointment for refractory ocular surface inflammation between January of 2010 and March of 2018 were reviewed retrospectively. Changes in ocular surface signs during slit-lamp examination, clinical symptoms and concurrent steroid use were graded with a scoring system. The presence of side effects was also assessed. The changes in disease severity and patient symptoms were compared between baseline and after the treatment. Results Among 72 patients (55% males, mean age 10.8 ± 3.9 years, range 3 to 17 years), 25 patients (48% males, mean age 11.4 ± 3.9 years) fully recovered, resulting in discontinuance of the ointment treatment before 12 months. Six patients experienced intolerable burning sensation, which required treatment cessation. Cessation days of those who quit were 1,5,14,20,26, and 35 days. Seven patients were lost during follow-up. Thirty-four patients (56% males, mean age 11.2 ± 4.2 years, range 3 to 17 years) were treated with tacrolimus ointment for over 12 months (average 23.1 ± 19.1 months, range 12 to 98 months). During the follow-up period, all patients showed improved clinical signs and symptoms, and no adverse reaction was noted. Conclusions Long-term maintenance of topical tacrolimus 0.02% ointment is safe and effective in improving refractory ocular surface inflammation in pediatric patients.