Case Series: Novel Utilization of Rho-Kinase Inhibitor for the Treatment of Corneal Edema

Ocular effects of Rho kinase (ROCK) inhibition: a systematic review

Topical therapies targeting Rho-associated protein kinase (ROCK) signalling, including netarsudil (Rhopressa®) and ripasudil (Glanatec®), have become widely adopted as part of standard clinical practice to lower intraocular pressure (IOP) in patients with ocular hypertension or glaucoma. Given the pleiotropic roles of ROCK signalling, ROCK inhibition has the potential to cause unintended ocular side effects beyond IOP lowering in other substructures of the eye, both beneficial and deleterious. Additional experience and observation of patients treated with this class of medications have uncovered both new side effects not reported in the initial clinical trials, as well as potential benefits that have inspired off-label uses and that have been the topic of numerous clinical studies, case series, case reports, and translational studies. Here, we performed a comprehensive systematic review and identified 170 studies describing ocular effects of ROCK inhibition. In addition to describing well-established ocular effects associated with inhibition of ROCK signalling, such as conjunctival hyperaemia, corneal verticillata, and reticular corneal epithelial oedema, we also highlight other effects, such as corneal haemorrhages, changes in corneal contour, anterior subcapsular opacities, contact dermatitis, punctal stenosis, and eyelid wound dehiscence, which have been described in case series and case reports. Finally, we evaluated studies describing potential novel applications of ROCK inhibition for treating disorders affecting the cornea, the retina, and the optic nerve, finding strong evidence in support of a beneficial effect of ROCK inhibitors on corneal oedema due to corneal endothelial cell dysfunction. The other potential applications require further research.

Laboratory exploration of the use of ripasudil in descemetorhexis with a human ex vivo model

The aim of the study was to investigate the effect of ripasudil on corneal endothelial cell survival and migration after two types of descemetorhexis on a human ex vivo model. Eleven human corneoscleral buttons were incubated in either 50 ml organ culture medium containing 10 μM ripasudil or 50 μl dimethyl sulfoxide (DMSO), the vehicle in ripasudil for 2 days prior to wound creation then for 14 days after. The wound was created with either full trephination scoring or by shallow trephination plus manual peeling. At day 14, immunohistochemistry with vimentin and Na+/K+/ATPase markers was conducted. Tissues were assessed at day 3, 7 and 14 for morphology, cell migration, cell viability and cell density. Full trephination scoring created more damage on tissues compared to shallow trephination with full Descemet membrane peeling. In the full trephination scoring group, no differences in cell viability were noted when ripasudil and DMSO were compared. With the peeling method, Ripasudil could protect the endothelial cell death and maintain the morphology compared to the control. At day 14, no differences in the peripheral cell viability and density were found between ripasudil and DMSO, although the ripasudil group presented significantly increased central cell count and cell viability. Increased cell migration was noted with ripasudil and the initial cell morphology of those migrated cells was similar to that of fibroblasts. In conclusion, ex vivo modelling suggested that peeling resulted in less cell damage than scoring and ripasudil maintained better morphology and promoted migration. These effects might be via transformation of endothelial cells into a more motile spindle-like phenotype.

Squishy matters - Corneal mechanobiology in health and disease

The cornea, as a dynamic and responsive tissue, constantly interacts with mechanical forces in order to maintain its structural integrity, barrier function, transparency and refractive power. Cells within the cornea sense and respond to various mechanical forces that fundamentally regulate their morphology and fate in development, homeostasis and pathophysiology. Corneal cells also dynamically regulate their extracellular matrix (ECM) with ensuing cell-ECM crosstalk as the matrix serves as a dynamic signaling reservoir providing biophysical and biochemical cues to corneal cells. Here we provide an overview of mechanotransduction signaling pathways then delve into the recent advances in corneal mechanobiology, focusing on the interplay between mechanical forces and responses of the corneal epithelial, stromal, and endothelial cells. We also identify species-specific differences in corneal biomechanics and mechanotransduction to facilitate identification of optimal animal models to study corneal wound healing, disease, and novel therapeutic interventions. Finally, we identify key knowledge gaps and therapeutic opportunities in corneal mechanobiology that are pressing for the research community to address especially pertinent within the domains of limbal stem cell deficiency, keratoconus and Fuchs' endothelial corneal dystrophy. By furthering our understanding corneal mechanobiology, we can contextualize discoveries regarding corneal diseases as well as innovative treatments for them.

The Role of Rho Kinase Inhibitors in Corneal Diseases

The cornea, as the outermost layer of the eye, plays a crucial role in vision by focusing light onto the retina. Various diseases and injuries can compromise its clarity, leading to impaired vision. This review aims to provide a thorough overview of the pharmacological properties, therapeutic potential and associated risks of Rho-associated protein kinase (ROCK) inhibitors in the management of corneal diseases. The article focuses on four key ROCK inhibitors: Y-27632, fasudil, ripasudil, and netarsudil, providing a comparative examination. Studies supporting the use of ROCK inhibitors highlight their efficacy across diverse corneal conditions. In Fuchs' endothelial corneal dystrophy, studies on the application of Y-27632, ripasudil, and netarsudil demonstrated noteworthy enhancements in corneal clarity, endothelial cell density, and visual acuity. In pseudophakic bullous keratopathy, the injection of Y-27632 together with cultured corneal endothelial cells into the anterior chamber lead to enhanced corneal endothelial cell density and improved visual acuity. Animal models simulating chemical injury to the cornea showed a reduction of neovascularization and epithelial defects after application of fasudil and in a case of iridocorneal endothelial syndrome netarsudil improved corneal edema. Addressing safety considerations, netarsudil and ripasudil, both clinically approved, exhibit adverse events such as conjunctival hyperemia, conjunctival hemorrhage, cornea verticillata, conjunctivitis, and blepharitis. Monitoring patients during treatment becomes crucial to balancing the potential therapeutic benefits with these associated risks. In conclusion, ROCK inhibitors, particularly netarsudil and ripasudil, offer promise in managing corneal diseases. The comparative analysis of their pharmacological properties and studies supporting their efficacy underscore their potential therapeutic significance. However, ongoing research is paramount to comprehensively understand their safety profiles and long-term outcomes in diverse corneal conditions, guiding their optimal application in clinical practice.

Evaluating the efficacy of Rho kinase inhibitor eye drops in the management of corneal edema: A single-center retrospective cohort study

PURPOSE

This study aimed to evaluate the efficacy of ripasudil in managing various corneal edema conditions.

MATERIALS AND METHODS

This single-center retrospective analysis was conducted at Hadassah Medical Center and involved 16 patients with 17 eyes. Patients were selected based on diagnostic criteria, primarily corneal edema. The conditions were as follows, listed by frequency: postcataract surgery (31.25%), postpenetrating keratoplasty (25%), post-Descemet's membrane endothelial keratoplasty (18.75%), Fuchs' endothelial corneal dystrophy (12.5%), status post-Ahmed glaucoma valve (6.25%), and status posttrabeculectomy (6.25%). The treatment regimen involved topical administration of ripasudil hydrochloride hydrate (Glanatec® 0.4%), administered three times a day or tailored to condition severity. Efficacy was assessed using pre- and posttreatment measurements of best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell count (ECC), along with slit-lamp and optical coherence tomography examinations.

RESULTS

The average duration of ripasudil treatment was approximately 4.9 ± 2.2 months. Significant improvements were observed in BCVA, changing from a pretreatment value of 1.106 ± 0.817 logMAR to a posttreatment value of 0.56 ± 0.57 logMAR (P = 0.0308). CCT also showed a significant reduction, from 619.50 ± 56.36 μm pretreatment to 572.5 ± 75.48 μm posttreatment (P = 0.0479). ECC showed a marginal but not statistically significant increase, from 849.00 ± 570.72 cells/mm² pretreatment to 874.75 ± 625.59 cells/mm² posttreatment (P = 0.9010).

CONCLUSION

The study provides robust evidence supporting the use of ripasudil in managing corneal edema. Significant improvements in key ocular metrics such as BCVA and CCT were observed, enhancing the overall quality of life for patients suffering from various forms of corneal edema.

Corneal Edema after Cataract Surgery

This systematic review investigates the prevalence and underlying causes of corneal edema following cataract surgery employing manual phacoemulsification. A comprehensive search encompassing databases such as PubMed, Embase, ProQuest, Cochrane Library, and Scopus was conducted, focusing on variables encompassing cataract surgery and corneal edema. Two independent reviewers systematically extracted pertinent data from 103 articles, consisting of 62 theoretical studies and 41 clinical trials. These studies delved into various aspects related to corneal edema after cataract surgery, including endothelial cell loss, pachymetry measurements, visual performance, surgical techniques, supplies, medications, and assessments of endothelial and epithelial barriers. This review, encompassing an extensive analysis of 3060 records, revealed significant correlations between corneal edema and endothelial cell loss during phacoemulsification surgery. Factors such as patient age, cataract grade, and mechanical stress were identified as contributors to endothelial cell loss. Furthermore, pachymetry and optical coherence tomography emerged as valuable diagnostic tools for assessing corneal edema. In conclusion, this systematic review underscores the link between corneal edema and endothelial cell loss in manual phacoemulsification cataract surgery. It highlights the relevance of factors like patient demographics and diagnostic modalities. However, further research is essential to unravel the complexities of refractive changes and the underlying mechanisms.

Topical Ripasudil for the Treatment of Segmental Corneal Edema: A Case Series

PURPOSE

Ripasudil, a rho-kinase inhibitor, has gained popularity as an adjunctive therapy after Descemet stripping only to hasten visual recovery. Ripasudil has been shown to increase corneal endothelial cell proliferation and intercellular adhesion, and decrease endothelial cell apoptosis. We present 4 cases in which persistent corneal edema after various anterior segment surgeries was successfully treated with topical ripasudil, and 1 case in which corneal edema did not improve with use of ripasudil.

METHODS

Retrospective chart review revealed 5 patients treated with topical ripasudil for persistent corneal edema that failed to improve with conventional, nonsurgical treatments.

RESULTS

In each case, the patient had symptomatic, persistent, focal corneal edema which followed a surgical procedure in the anterior segment. The various etiologies of corneal edema included graft failure after Descemet stripping endothelial keratoplasty, a failed penetrating keratoplasty, and 3 cases of pseudophakic corneal edema. These patients experienced improved vision and partial or complete resolution of corneal edema after 2 to 4 weeks of topical ripasudil administered 4 times daily. One patient with pseudophakic bullous keratopathy had edema that initially improved on topical ripasudil, but after cessation of the medication, developed progressive corneal edema and required endothelial keratoplasty.

CONCLUSIONS

In patients with focal corneal edema resulting from surgical trauma to the endothelium who failed to clear over time with conservative measures, topical ripasudil was shown to be an effective treatment option that in most cases improved vision and helped reduce the need for endothelial transplantation.

Descemet Stripping Only Technique for Corneal Endothelial Damage in Mice

PURPOSE

Descemet stripping only is an emerging surgical technique used to remove central Descemet membrane and corneal endothelial cells in patients with corneal endothelial disease. Here, we describe a murine model of this procedure to help facilitate basic science investigation and evaluation of postoperative outcomes using this surgical technique.

METHODS

Slitlamp biomicroscopy, central corneal thickness assessment (by optical coherence tomography), and immunohistochemistry were used to assess the model through 7 weeks of follow-up.

RESULTS

Complete removal of the endothelium and Descemet membrane was confirmed by slitlamp biomicroscopy and by histology. Central corneal thickness peaked at day 1 postinjury and then declined over the course of 2 weeks to a stable level of persistent edema. Seven weeks postinjury, immunohistochemical staining for ZO-1 showed the area of Descemet stripping was fully covered by enlarged and dysmorphic corneal endothelial cell. No significant ocular complications were appreciated through the end of the follow-up.

CONCLUSIONS

We demonstrate the feasibility of and provide detailed instructions for a murine model of Descemet stripping only. This model provides a potential in vivo platform to investigate the mechanisms and biology of this emerging surgical procedure.

Recent and Evolving Therapies in the Management of Endothelial Diseases

Corneal endothelium is the innermost layer of the cornea which has both barrier and pump function and very important to maintain cornea clarity. Unlike epithelium, endothelium does not have regenerative potential; hence, endothelial damage or dysfunction could lead to corneal edema and visual impairment. Advanced corneal transplantation which involves selective replacement of dysfunctional endothelium has led to improved and faster visual rehabilitation. But in recent times, alternative therapies in the management of corneal edema and endothelial diseases have been reported. In this review, we aim to give a comprehensive review of various strategies for the management of corneal endothelial dysfunction in order to give treatment which is precisely tailored for each individual patient. A review of all peer-reviewed publications on novel strategies for the management of endothelial dysfunction was performed. The various approaches to the management of endothelial dysfunction are compared and discussed. Shortage of human donor corneas globally is fuelling the search for keratoplasty alternatives. Corneal endothelial dysfunction can be caused following surgery, laser or corneal endothelial dystrophies which could be amenable to treatment with pharmacological, biological intervention and reverse the endothelial dysfunction in the early stages of endothelial failure. Pharmacological and surgical intervention are helpful in cases of good peripheral endothelial cell reserve, and advanced cases of endothelial cell dysfunction can be targeted with cell culture therapies, gene therapy and artificial implant. Treatment strategies which target endothelial dysfunction, especially FECD in its early stages, and gene therapy are rapidly evolving. Therapies which delay endothelial keratoplasty also are evolving like DSO and need more studies of long-term follow-up and patient selection criteria.

Reticular corneal epithelial edema with topical netarsudil

Rho-associated protein kinase inhibitor (ROCK) therapy for corneal endothelial dysfunction or damage other than glaucoma has been reported with few ocular side effects. We report reticular epithelial edema (REE) with netarsudil (0.02%) therapy in four cases with different clinical scenarios (three cases with corneal transplant and one case postcataract extraction). REE developed in all cases variably and cleared on cessation of netarsudil in three cases. One case was continued on netarsudil due to REE sparing the visual axis with no active ocular complaints. Partial clearance of stromal edema observed in all cases was correlated clinically to visual acuity considering existing comorbidities in an individual case.

A systematic review on the effects of ROCK inhibitors on proliferation and/or differentiation in human somatic stem cells: A hypothesis that ROCK inhibitors support corneal endothelial healing via acting on the limbal stem cell niche

Rho kinase inhibitors (ROCKi) have attracted growing multidisciplinary interest, particularly in Ophthalmology where the question as to how they promote corneal endothelial healing remains unresolved. Concurrently, stem cell biology has rapidly progressed in unravelling drivers of stem cell (SC) proliferation and differentiation, where mechanical niche factors and the actin cytoskeleton are increasingly recognized as key players. There is mounting evidence from the study of the peripheral corneal endothelium that supports the likelihood of an internal limbal stem cell niche. The possibility that ROCKi stimulate the endothelial SC niche has not been addressed. Furthermore, there is currently a paucity of data that directly evaluates whether ROCKi promotes corneal endothelial healing by acting on this limbal SC niche located near the transition zone. Therefore, we performed a systematic review examining the effects ROCKi on the proliferation and differentiation of human somatic SC, to provide insight into its effects on various human SC populations. An appraisal of electronic searches of four databases identified 1 in vivo and 58 in vitro studies (36 evaluated proliferation while 53 examined differentiation). Types of SC studied included mesenchymal (n = 32), epithelial (n = 11), epidermal (n = 8), hematopoietic and other (n = 8). The ROCK 1/2 selective inhibitor Y-27632 was used in almost all studies (n = 58), while several studies evaluated ≥2 ROCKi (n = 4) including fasudil, H-1152, and KD025. ROCKi significantly influenced human somatic SC proliferation in 81% of studies (29/36) and SC differentiation in 94% of studies (50/53). The present systemic review highlights that ROCKi are influential in regulating human SC proliferation and differentiation, and provides evidence to support the hypothesis that ROCKi promotes corneal endothelial division and maintenance via acting on the inner limbal SC niche.

Rho-kinase inhibitors: Role in corneal endothelial disorders

PURPOSE

This exhaustive review of published literature aims to put forth the current understanding, and experiences of the role Rho-kinase inhibitors play in the management of corneal endothelial disorders.

METHODS

A meticulous search for PubMed and Medline databases was carried out using keywords 'rho-kinase inhibitors', 'corneal endothelial disorders', 'rho-kinase inhibitors in corneal endothelial disorders', and 'fuchs endothelial corneal dystrophy'. The articles published in last five years relevant to the area of interest were selected and compiled in a chronological order to write this review.

RESULTS

Published research shows the proven role of rho-kinase inhibitors in promoting endothelial proliferation and suppressing its apoptosis. It has shown to be effective in the treatment of endothelial diseases and endothelial cell loss due to other causes in small clinical studies. It has also shown to promote growth of human corneal endothelial cell culture suitable for transplantation. The side effects of topical rho-kinase inhibitors are minimal and self-limiting.

CONCLUSION

Rho-kinase inhibitors show immense promise in providing a non-surgical therapy for treatment of endothelial disorders. If consistent results are demonstrated through large clinical trials then this can be a major breakthrough in treating endothelial decompensation and reduce our dependence on endothelial keratoplasty for the same.

Phase 2, Randomized, Open-Label Parallel-Group Study of Two Dosing Regimens of Netarsudil for the Treatment of Corneal Edema Due to Fuchs Corneal Dystrophy

Background: This phase 2 study evaluated the therapeutic potential of netarsudil to reduce corneal edema and to improve vision in patients with Fuchs corneal dystrophy (FCD). Methods: Patients (N = 40) with baseline central corneal thickness (CCT) of ≥600 μm and best-corrected visual acuity (BCVA) of 70-20 letters (20/40-20/400 Snellen equivalent) were randomized 1:1 to receive netarsudil once a day (QD) or twice a day (BID) for 8 weeks. Primary endpoint was mean CCT change from baseline at week 4. Results: Netarsudil QD and BID significantly reduced CCT at week 4 [mean change (standard error of mean), 28.4 (7.99) μm, P = 0.0021; and 20.1 (8.75) μm, P = 0.0335, respectively]. Five (12.5%) patients achieved complete resolution of corneal edema at week 4. BCVA improved by 3.2 (2.76) letters with QD and 1.5 (2.84) letters with BID, and 10 (25%) patients [5 with QD (P = 0.0078) and 5 with BID (P = 0.0096)] gained ≥10 letters at week 4. Improvements in CCT and vision were observed at week 2 and persisted at week 8, without significant differences between the 2 doses at any time point. Netarsudil QD significantly improved visual acuity and glare factor scores on the Visual Function and Corneal Health Status (V-FUCHS) questionnaire at weeks 4 and 8 (mean change, -0.4 to -0.3; P ≤ 0.0200). Netarsudil was well tolerated. Reticular edema developed in one (2.5%) patient with BID, which resolved with treatment discontinuation. Conclusions: Netarsudil QD led to significant reductions in corneal edema as well as improvements in vision and patient-reported symptoms of glare and visual impairment in patients with FCD. Clinical Trial Registration Number: NCT04498169.

Corneal endothelial wound healing: understanding the regenerative capacity of the innermost layer of the cornea

Currently, there are very few well-established treatments to stimulate corneal endothelial cell regeneration in vivo as a cure for corneal endothelial dysfunctions. The most frequently performed intervention for a damaged or dysfunctional corneal endothelium nowadays is corneal endothelial keratoplasty, also known as lamellar corneal transplantation surgery. Newer medical therapies are emerging and are targeting the regeneration of the corneal endothelium, helping the patients regain their vision without the need for donor tissue. Alternatives to donor tissues are needed as the aging population requiring transplants, has further exacerbated the pressure on the corneal eye banking system. Significant ongoing research efforts in the field of corneal regenerative medicine have been made to elucidate the underlying pathways and effector proteins involved in corneal endothelial regeneration. However, the literature offers little guidance and selective attention to the question of how to fully exploit these pathways. The purpose of this paper is to provide an overview of wound healing characteristics from a biochemical level in the lab to the regenerative features seen in the clinic. Studying the pathways involved in corneal wound healing together with their key effector proteins, can help explain the effect on the proliferation and migration capacity of the corneal endothelial cells.

Case Report: Topical Netarsudil in the Treatment of a Neurotrophic Corneal Ulcer

SIGNIFICANCE

Rho-associated kinase inhibitors have been utilized in glaucoma management for reducing intraocular pressure. Their role in treating corneal endothelial damage and promoting corneal epithelial healing have also been reported. Presented is, a case report demonstrating healing of a previously non-responsive neurotrophic ulcer with addition of the Rho-associated kinase inhibitor, netarsudil.

PURPOSE

Early in vitro based research on corneal application of Rho-associate kinase inhibitors has shown these molecules to be beneficial to corneal epithelial wound healing. The presented case supports their use in epithelial disease. It is the author's hope this will inspire further investigation.

CASE REPORT

Presented here is a case report describing the use of netarsudil, a Rho-associated kinase inhibitor in the management of a neurotrophic corneal ulcer that was non-responsive to frontline therapy. The application of netarsudil was followed by rapid healing of the defect, though a concomitant increase in mucous production was also noted.

CONCLUSIONS

This case supports the use of netarsudil as an agonist of epithelial healing, though further research is needed.

New Horizons in the Treatment of Corneal Endothelial Dysfunction

The treatment of corneal endothelial dysfunction has experienced a revolutionary change in the past decades with the emergence of endothelial keratoplasty techniques: descemet stripping automated endothelial keratoplasty (DSAEK) and descemet membrane endothelial keratoplasty (DMEK). Recently, new treatments such as cultivated endothelial cell therapy, Rho-kinase inhibitors (ROCK inhibitors), bioengineered grafts, and gene therapy have been described. These techniques represent new lines of treatment for endothelial dysfunction. Their advantages are to help address the shortage of quality endothelial tissue, decrease the complications associated with tissue rejection, and reduce the burden of postoperative care following transplantation. Although further randomized clinical trials are required to validate these findings and prove the long-term efficacy of the treatments, the positive outcomes in preliminary clinical studies are a stepping stone to a promising future. Our aim is to review the latest available alternatives and advancements to endothelial corneal transplant.

Rho kinase (ROCK) inhibitors in the management of corneal endothelial disease

PURPOSE OF REVIEW

Rho kinase (ROCK) inhibitors are growing increasingly relevant in ophthalmology, and the goal of this review is to summarize their mechanisms of action and potential applications in the subspecialties of glaucoma, retina, and cornea. We will focus specifically on corneal endothelial wound healing, for which ROCK inhibition demonstrates particular promise.

RECENT FINDINGS

ROCK inhibition has been shown to promote corneal endothelial cell proliferation, increase intercellular adhesion, and suppress apoptosis. Topical ROCK inhibitor treatment has exhibited potential use in Fuchs endothelial dystrophy, corneal edema from acute surgical trauma and other etiologies, and tissue engineering therapy for the endothelial disease. Ripasudil and netarsudil, the two ROCK inhibitors available for ophthalmic use, are generally very well tolerated with mild and transient local side effects.

SUMMARY

ROCK inhibitors are revolutionizing the subspecialty of cornea, and further research is needed to compare long-term outcomes of ROCK inhibitor therapy to those of conventional endothelial keratoplasty, including visual acuity and endothelial cell density. Other possible avenues include the use of ROCK inhibitors to prolong corneal graft survival, and early data appears promising.