Clinical Characteristics and Risk Factors of Recurrent Mooren's Ulcer

The Role of Neutrophil Extracellular Traps in the Ocular System

Purpose: Neutrophils remain at the top of congenital and adaptive immune systems. The past 20 years witnessed a steep rise in the interest in neutrophil extracellular traps (NETs), which are a novel type of anti-pathogen mechanism coordinated with neutrophils. However, accumulating data revealed that excessive NETs in the host were associated with exacerbated inflammation, thrombosis, and autoimmunity. Increasing evidence found the participation of NETs in the pathophysiological process of many infectious and sterile diseases in the ocular system. Therefore, we discussed the role of neutrophil extracellular traps in the ocular system in this review.Methods: Articles were searched on PubMed, Embase and Web of science up to December 2021.Results: In this review, we exhibited the protective role of neutrophils patrolling the ocular surface from invading pathogens and their contribution to exacerbated inflammation and thrombogenesis in some ocular diseases. We also discussed the physiological and pathological processes of NET generation to identify novel biomarkers and therapeutic targets to interrupt immoderate NET formation and alleviate NET-induced harmful effects.Conclusions: Neutrophils and NETs are quite important for immune responses in the ocular system, while their negative effects on ocular tissue should also be emphasized, which could serve as novel biomarkers and potential therapeutic targets.

Increased cGAS/STING signaling components in patients with Mooren's ulcer

AIM

To explore the expression of cGAS/STING signaling components in Mooren's ulcer (MU).

METHODS

Samples were obtained from ten MU patients, and eight residual corneal-scleral rings of healthy donor corneas for controls. Human corneal epithelial cells (HCECs) were used to evaluate the effect of cGAS/STING signaling pathway. Immunohistochemistry (IHC) and Western blot were used to examine the expression of cGAS, STING, and phosphorylated interferon regulatory factor 3 (p-IRF3) in MU tissues. The expression of interferon-β (IFN-β) and interferon-stimulated genes (ISGs) was quantified by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The protein levels of cGAS and STING in MU samples were significantly elevated when compared with the healthy controls by Western blot and IHC. After stimulation with cGAMP, real-time PCR and ELISA showed a dramatic increase of IFN-β and ISGs (containing CXCL10, IFIT1, and IL-6) in HCECs. Moreover, HCECs treated with cGAMP was characterized by increased phosphorylation and more nuclear translocation of IRF3. Meanwhile, increased p-IRF3 was observed in MU samples via IHC and Western blot.

CONCLUSION

The pronounced expression of cGAS/STING signaling components in the patients with MU and probably contribute to the onset and development of MU.

Comparative Study on the Efficacy of Frozen Amniotic Membrane Transplantation and Lamellar Keratoplasty in the Treatment of Mooren Ulcer

OBJECTIVE

To compare of the clinical efficacy of frozen amniotic membrane transplantation (AMT) and lamellar keratoplasty (LKP) in the treatment of Mooren ulcer.

METHOD

Forty patients (42 eyes) with Mooren's ulcer in our hospital from January 2010 to January 2019 were divided into frozen AMT group (20 eyes) and LKP group (22 eyes). Comparative observation of post-operative best corrected visual acuity (BCVA), corneal epithelial healing time, corneal epithelialization time, ulcer healing, corneal transparency, corneal graft transparency, neovascularization and original disease recurrence were observed.

RESULTS

The average BCVA at post-operative 6 and 12 months in LKP group were significantly lower than AMT group (P < 0.05). The ulcer healing rates in LKP group (63.6) were significantly higher than AMT group (30) (P < 0.05). The corneal epithelialization time of LKP group were 9.55 ± 1.26 days. The corneal epithelial healing time of AMT group were 13.50 ± 2.21 days. Nine cases were corneal graft transparency grade 0, and 13 cases were grade I. Three eyes in AMT group were corneal transparency grade 0, 7 were grade I and 10 were grade II. Corneal neovascularization were observed in 3 eyes in AMT group and 4 eyes in LKP group. The original disease recurrence rates in LKP group (50) were significantly higher than AMT group (20) (P < 0.05). Four cases of primary corneal transplantation failure were observed in LKP group.

CONCLUSION

Lamellar keratoplasty group obtained significantly better BCVA during follow-up and faster healing time than the frozen AMT group while frozen AMT group had lower original disease recurrence rates than LKP group.

Treatment of Mooren's ulcer coexisting with a pterygium using an intrastromal lenticule obtained from small-incision lenticule extraction: case report and literature review

The coexistence of Mooren’s ulcer and a pterygium is an extremely rare ocular condition that has been infrequently reported in the literature to date. We herein present the first case of treatment of Mooren’s ulcer coexisting with a pterygium using a lenticule obtained by myopic small-incision lenticule extraction (SMILE). A 61-year-old woman presented with a 3-month history of recurrent ocular pain and red eye caused by Mooren’s ulcer coexisting with a pterygium. She received topical immunosuppressive and anti-infection treatments for almost 3 months. However, her ocular symptoms and signs did not substantially improve. Therefore, we performed lamellar keratoplasty with a corneal lenticule obtained by SMILE, followed by pterygium excision combined with conjunctival autografting. The patient recovered well with no complications or recurrence 1 year postoperatively. Our success suggests that combined surgery may be an effective management for coexistence of Mooren’s ulcer and a pterygium if conservative treatments fail. A corneal lenticule obtained by SMILE can be used as the lamellar keratoplasty graft in such patients.

[Mooren's ulcer]

The article reviews available data on Mooren's ulcer - a rare disease of, supposedly, autoimmune origin that manifests as peripheral ulceration of the cornea and poses a risk of its perforation. The variability of clinical presentation and course of the disease often leads to misdiagnosis and inadequate treatment. The present review focuses on specific signs characteristic of the disease and the most effective methods of its treatment.

Bilateral Boston keratoprosthesis type 1 in a case of severe Mooren's ulcer

INTRODUCTION

Mooren's ulcer is a painful, inflammatory chronic keratitis that affects corneal periphery, progressing centripetally, ultimately ending in perforation. The first line of treatment includes systemic immunomodulators, with surgery being the last option. We present a case of bilateral Boston keratoprosthesis implantation for severe Mooren's ulcer that responded differently in each eye.

CLINICAL CASE

A 32-year-old male with corneal opacification, anterior staphylomas, vision of hand movement, was started on systemic immunosuppression with cyclosporine. After two failed penetrating keratoplasties in each eye, high intraocular pressure despite diode cyclophotocoagulation, and cystic macular edema, we performed Boston keratoprosthesis type 1 in both eyes. The right eye responded initially well, with a best-corrected visual acuity of 20/80 and normal intraocular pressure. The left eye presented high intraocular pressure, which required cyclophotocoagulation, ultimately resulting in hypotony. Boston keratoprosthesis was performed but had peripheral corneal necrosis that progressed despite amniotic membrane transplantation and aggressive intensive treatment with medroxyprogesterone, autologous platelet-rich-in-growth-factors eye drops, and oral doxycycline. Thus, replacement of the semi-exposed Boston keratoprosthesis with tectonic penetrating keratoplasty was necessary. However, both eyes developed phthisis bulbi with final visual acuity of perception of light with poor localization.

CONCLUSION

Mainstay treatment of Mooren's ulcer is systemic immunomodulation. Surgical treatment must be considered only when risk of perforation, preferably with inflammation under control. Penetrating keratoplasty frequently fails, and Boston keratoprosthesis may be a viable option. However, postoperative complications, especially uncontrolled high intraocular pressure, corneal necrosis, and recurrence of Mooren's ulcer may jeopardize the outcomes and need to be addressed promptly with intensive topical and systemic treatment.