The Neuropeptide α-Melanocyte-Stimulating Hormone Prevents Persistent Corneal Edema following Injury.

Corneal endothelial cells (CEnCs) regulate corneal hydration and maintain tissue transparency through their barrier and pump function. However, these cells exhibit limited regenerative capacity following injury. Currently, corneal transplantation is the only established therapy for restoring endothelial function, and there are no pharmacologic interventions available for restoring endothelial function. This study investigated the efficacy of the neuropeptide α-melanocyte-stimulating hormone (α-MSH) in promoting endothelial regeneration during the critical window between ocular injury and the onset of endothelial decompensation using an established murine model of injury using transcorneal freezing. Local administration of α-MSH following injury prevented corneal edema and opacity, reduced leukocyte infiltration, and limited CEnC apoptosis while promoting their proliferation. These results suggest that α-MSH has a proregenerative and cytoprotective function on CEnCs and shows promise as a therapy for the prevention and management of corneal endothelial dysfunction.

Myeloid-derived suppressor cells promote allograft survival by suppressing regulatory T cell dysfunction in high-risk corneal transplantation.

Highly inflamed and neovascularized corneal graft beds are known as high-risk (HR) environments for transplant survival. One of the primary factors leading to this rejection is reduction in the suppressive function of regulatory T cells (Treg). Our results show that myeloid-derived suppressor cells (MDSC) counteract interleukin-6-mediated Treg dysfunction by expressing interleukin-10. Additionally, MDSC maintain forkhead box P3 stability and their ability to suppress IFN-γ+ Th1 cells. Administering MDSC to HR corneal transplant recipients demonstrates prolonged graft survival via promotion of Treg while concurrently suppressing IFN-γ+ Th1 cells. Moreover, MDSC-mediated donor-specific immune tolerance leads to long-term corneal graft survival as evidenced by the higher survival rate or delayed survival of a second-party C57BL/7 (B6) graft compared to those of third-party C3H grafts observed in contralateral low-risk or HR corneal transplantation of BALB/c recipient mice, respectively. Our study provides compelling preliminary evidence demonstrating the effectiveness of MDSC in preventing Treg dysfunction, significantly improving graft survival in HR corneal transplantation, and showing promising potential for immune tolerance induction.

IL-6 induces Treg dysfunction in desiccating stress-induced dry eye disease.

Regulatory T cells (Tregs) play a critical role in maintaining immune homeostasis, and their dysfunction is implicated in the pathogenesis of various autoimmune disorders, including dry eye disease (DED). Treg dysfunction in DED allows T-helper cell 17 (Th17) mediated chronic inflammation at the ocular surface. In this study, the factors causing Treg dysfunction in DED were investigated. We observed reduced expression of Treg functional markers - FoxP3, CD25, and CTLA-4 in the cells isolated from DED mice (DED Tregs). Additionally, DED Tregs showed increased expression levels of receptors for pro-inflammatory cytokine receptors, namely IL-6R, IL-17RA, and IL-23R. An increased expression level of pro-inflammatory cytokine receptors was observed on exposing Tregs isolated from naïve mice (NTregs) to IL-6 or IL-17, but not IL-23, with a concomitant downregulation of FoxP3, CD25, and CTLA-4 in these cells. Furthermore, among these cytokines, IL-6 induced the most pronounced loss of Treg mediated suppression of Th17 proliferation and IL-10 secretion. In vitro and in vivo blockade of IL-6 effectively restored function in DED Tregs, leading to enhanced suppressive function against proliferating Th17 cells and ameliorating disease severity. In conclusion, this study provides insights into mechanisms of Treg dysregulation in DED, specifically delineating the effect of Th17-associated cytokines, with IL-6 emerging as the critical factor inducing Treg dysfunctionality. These findings highlight the potential for developing novel therapeutic interventions for DED through restoration of immunosuppressive function of Tregs.

The impact of donor diabetes on corneal transplant immunity.

Corneal transplantation is the most common form of solid tissue grafting, with an approximately 80% to 90% success rate. However, success rates may decline when donor tissues are derived from patients with a history of diabetes mellitus (DM). To evaluate the underlying immunopathologic processes that cause graft rejection, we used streptozotocin-induced type 1 DM (DM1) and transgenic Lepob/ob type 2 DM (DM2) diabetic murine models as donors and nondiabetic BALB/c as recipients. DM resulted in an increased frequency of corneal antigen-presenting cells (APCs) with an acquired immunostimulatory phenotype. Following transplantation, recipients that received either type of diabetic graft showed increased APC migration and T helper type 1 alloreactive cells, impaired functional regulatory T cells, and graft survival. Insulin treatment in streptozotocin-induced diabetic mice led to an increased tolerogenic profile of graft APC, lower T helper type 1 sensitization, and a higher frequency of functional regulatory T cells with high suppressive capacity, reflected in increased graft survival. We conclude that both DM1 and DM2 in donors can impact corneal APC functional phenotype, rendering the tissue more immunogenic and thereby increasing the risk of graft failure.

Vaccine-Associated Uveitis after COVID-19 Vaccination: Vaccine Adverse Event Reporting System Database Analysis.

PURPOSE: To assess the risk of vaccine-associated uveitis (VAU) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and evaluate uveitis onset interval and clinical presentations in the patients. DESIGN: A retrospective study from December 11, 2020, to May 9, 2022, using the Centers for Disease Control and Prevention Vaccine Adverse Event Reporting System. PARTICIPANTS: Patients diagnosed with VAU after administration of BNT162b2 (Pfizer-BioNTech, Pfizer Inc/BioNTech SE), mRNA-1273 (Moderna, Moderna Therapeutics Inc), and Ad26.COV2.S (Janssen, Janssen Pharmaceuticals) vaccine worldwide. METHODS: A descriptive analysis of the demographics, clinical history, and presentation was performed. We evaluated the correlation among the 3 vaccines and continuous and categorical variables. A post hoc analysis was performed between uveitis onset interval after vaccination and age, dose, and vaccine type. Finally, a 30-day risk analysis for VAU onset postvaccination was performed. MAIN OUTCOME MEASURES: The estimated global crude reporting rate, observed to expected ratio of VAU in the United States, associated ocular and systemic presentations, and onset duration. RESULTS: A total of 1094 cases of VAU were reported from 40 countries with an estimated crude reporting rate (per million doses) of 0.57, 0.44, and 0.35 for BNT162b2, mRNA-1273, and Ad26.COV2.S, respectively. The observed to expected ratio of VAU was comparable for BNT162b2 (0.023), mRNA-1273 (0.025), and Ad26.COV2.S (0.027). Most cases of VAU were reported in patients who received BNT162b2 (n = 853, 77.97%). The mean age of patients with VAU was 46.24 ± 16.93 years, and 68.65% (n = 751) were women. Most cases were reported after the first dose (n = 452, 41.32%) and within the first week (n = 591, 54.02%) of the vaccination. The onset interval for VAU was significantly longer in patients who received mRNA-1273 (21.22 ± 42.74 days) compared with BNT162b2 (11.42 ± 23.16 days) and rAd26.COV2.S (12.69 ± 16.02 days) vaccines (P < 0.0001). The post hoc analysis revealed a significantly shorter interval of onset for the BNT162b2 compared with the mRNA 1273 vaccine (P < 0.0001). The 30-day risk analysis showed a significant difference among the 3 vaccines (P < 0.0001). CONCLUSIONS: The low crude reporting rate and observed to expected ratio suggest a low safety concern for VAU. This study provides insights into a possible temporal association between reported VAU events and SARS-CoV-2 vaccines; however, further investigations are required to delineate the associated immunological mechanisms.

Ophthalmic injuries from the beirut blast: Managing long-term consequences.

The 2020 Beirut Port explosion was one of the largest non-nuclear urban explosions in history, and resulted in a plethora of oculofacial injuries. In this retrospective study, we present the two year follow up ophthalmic outcomes of the survivors of the blast. Only 16 out of 39 patients continued follow up at our center, with 13 having delayed complications and 7 requiring further surgery. The most common delayed complications related to the eyelid, lacrimal system, and orbit. Treatment of disfiguring facial and peri-ocular scarring with laser-assisted drug delivery of topical 5-fluorouracil showed great promise and significantly improved patients' functional and well as cosmetic outcomes.

Phacoemulsification with and without iStent: A Systematic Review and Meta-Analysis of Comparative Studies.

BACKGROUND: The iStent (Glaukos Corporation; Laguna Hills, CA, USA) is one of the minimally invasive glaucoma devices. It can be inserted at the time of phacoemulsification or as a stand-alone procedure to lower the intraocular pressure (IOP). OBJECTIVE: Our aim was to conduct a systematic review and meta-analysis comparing the effect of iStent insertion at the time of phacoemulsification with phacoemulsification alone in patients with ocular hypertension or open-angle glaucoma. METHODS: We searched EMBASE, MEDLINE (OVID and PubMed), CINAHL, and Cochrane Library for articles published between 2008 and June 2022 (PRISMA 2020 for the checklist). Studies comparing the IOP-lowering effect of iStent with phacoemulsification versus phacoemulsification alone were included. The endpoints were IOP reduction (IOPR) and the mean reduction in the number of glaucoma drops. A quality-effects model was used to compare both surgical groups. RESULTS: Ten studies were included, reporting on 1,453 eyes. Eight hundred fifty three eyes had the combined iStent and phacoemulsification, and 600 eyes underwent phacoemulsification alone. IOPR was higher in the combined surgery at of 4.7 ± 2 mm Hg compared to 2.8 ± 1.9 mm Hg in phacoemulsification alone. A greater decrease in postoperative eye drops was noted in the combined group having a decrease of 1.2 ± 0.3 eye drops versus of 0.6 ± 0.6 drops in isolated phacoemulsification. The quality effect model showed an IOPR weighted mean difference (WMD) of 1.22 mm Hg (confidence interval [CI]: [-0.43, 2.87]; Q = 315.64; p < 0.01; I2 = 97%) and decreased eye drops WMD 0.42 drops (CI: [0.22, 0.62]; Q = 42.6; p < 0.01; I2 = 84%) between both surgical groups. Subgroup analysis shows that the new generation iStent may be more effective in reducing IOP. CONCLUSION: iStent has a synergetic effect with phacoemulsification. The reduction of IOP and glaucoma eye drops was higher when iStent is combined with phacoemulsification compared with isolated phacoemulsification.

Corneal Sensitivity and Neuropathy in Patients With Ocular Graft-Versus-Host Disease.

PURPOSE: To assess corneal sensitivity changes in patients with ocular graft-versus-host disease using a non-contact and Cochet-Bonnet esthesiometer. In addition, we evaluate the association between corneal sensitivity and subbasal nerve changes and epitheliopathy in these patients. METHODS: In this retrospective study, the clinical data and images were evaluated for 36 patients (19 female, 17 male) who fulfilled the inclusion criteria. The analyzed data included demographic and ocular surface parameters, including best-corrected visual acuity, corneal sensitivity with non-contact (mbar) and Cochet-Bonnet (cm) esthesiometer, corneal fluorescein staining (CFS) and symptoms scores, tear volume (Schirmer-I test, mm/5'), and subbasal nerve density (µm/mm2; assessed with in vivo confocal microscopy). RESULTS: The mean age of the study cohort was 59.9 ± 10.5 years. The mean corneal sensitivity assessed by Cochet-Bonnet and non-contact esthesiometer was 5.9 ± 0.3 cm and 7.3 ± 2.0 mbar, respectively. The ocular surface parameters included a corneal fluorescein staining (CFS) score, as per the National Eye Institute grading scheme, of 6.9 ± 3.5, and a Schirmer-I test result of 7.5 ± 6.2 mm/5 minutes.. Total corneal subbasal nerve density was inversely associated with CFS scores (r = -0.74; P < 0.001). Moreover, similar correlations between CFS scores and main trunk (r = -0.62; P < 0.001) and branch (r = -0.59; P < 0.001) nerve densities were observed. A significant correlation was found between reduced corneal sensitivity and higher CFS scores (r = 0.66; P < 0.001). Higher pressures were correlated with lower total (r = -0.83; P < 0.001), main trunk (r = -0.62; P < 0.001), and branch (r = -0.72; P < 0.001) nerve densities. The univariate analysis showed that corneal sensitivity loss (assessed with non-contact esthesiometer) was correlated with advanced age of the patients (P = 0.049) and inversely associated with total (P < 0.001), main trunk (P < 0.001), and branch (P < 0.001) nerve densities. In addition, sensitivity loss was inversely associated with punctal occlusion (cauterization (P = 0.001) or plug placement (P < 0.001). The multivariate analysis adjusted for age and punctal occlusion confirmed the associations in the univariate analysis. CONCLUSIONS: In this study, we observed that corneal sensitivity loss was associated with reduced main trunk, branch, and total nerve density in patients with ocular graft-versus-host disease. In addition, a significant correlation was observed between reduced corneal nerve density, corneal sensitivity, and severity of epitheliopathy.

Substance P regulates memory Th17 cell generation and maintenance in chronic dry eye disease.

Substance P (SP) is a neuropeptide expressed by nerves and an array of cells that serves as a critical mediator of neuroinflammation. Our recent work has demonstrated that blocking the preferred receptor for SP, neurokinin-1 receptor (NK1R), effectively suppresses the induction of acute dry eye disease (DED) by preserving regulatory T cell (Treg) function, while inhibiting antigen-presenting cell (APC) maturation and subsequent generation of effector Th17 cells (eTh17). Clinically, DED is a chronic disorder characterized by sustained ocular surface inflammation which is mediated by long-lived memory Th17 cells (mTh17) demonstrated in our well-established chronic DED model. The present study aimed to further understand the function of SP in the chronic phase of DED and its role in regulating the underlying pathogenic mTh17. In vitro culture of effector T cells isolated from acute DED with SP led to an enhanced conversion of eTh17 to mTh17, while culturing memory T cells isolated from chronic DED with SP effectively preserved the mTh17 cells. In contrast, the addition of an NK1R antagonist in the cultures abolished the SP-mediated effects. Furthermore, in vivo treatment with the NK1R antagonist during the resolution phase of acute DED significantly suppressed mTh17 generation, and treatment in the chronic phase of DED disrupted the maintenance of mTh17. Taken together, our results demonstrate that increased expression of SP promotes mTh17 generation and maintenance in chronic DED, and thus blockade of SP represents a novel promising mTh17-targeting strategy in treating chronic ocular surface inflammation.

Therapeutic Effects of Stimulating the Melanocortin Pathway in Regulating Ocular Inflammation and Cell Death.

Alpha-melanocyte-stimulating hormone (α-MSH) and its binding receptors (the melanocortin receptors) play important roles in maintaining ocular tissue integrity and immune homeostasis. Particularly extensive studies have demonstrated the biological functions of α-MSH in both immunoregulation and cyto-protection. This review summarizes the current knowledge of both the physiological and pathological roles of α-MSH and its receptors in the eye. We focus on recent developments in the biology of α-MSH and the relevant clinical implications in treating ocular diseases.

Assessment of Corneal Graft Outcomes in a Murine Model of Endothelial Keratoplasty.

Objectives: In this study, we establish a protocol for evaluating the outcomes of endothelial keratoplasty, including graft survival, rejection, or failure. Additionally, we also evaluate the alloimmune response in graft recipients. Methods: We performed EK using C57BL/6 (allogeneic) and BALB/c (syngeneic) as donors and BALB/c mice as recipients. Slit-lamp examination and optical coherence tomography were performed for clinical evaluations for 16 weeks post-procedure. Criteria for the assessment of corneal opacity were established and the animals were graded weekly. Additionally, we assessed corneal endothelial cell density by harvesting the corneas and staining with zonula occludens-1 (ZO-1). Lastly, lymph nodes were collected, and CD4+ T cells were MACS-sorted and co-cultured with syngeneic or allogeneic antigen-presenting cells (APCs) to assess the IFN-γ expression levels by alloreactive Th1 cells (ELISPOT) in response to the direct (donor) or indirect (host) pathways of sensitization. Results: We observed graft failure in four animals, including irreversible corneal opacity, graft detachment, and anterior synechiae in the first four weeks. The remaining animals were graded between 0 and 5 as per the established criteria. The total and graft corneal thickness and endothelial cell density progressively worsened with a higher grade of corneal opacity. The direct allosensitization of Th1 cells was significantly higher in mice with a higher grade of corneal opacity. At 16 weeks follow-up, the grafts remained stable with low opacity scores in syngeneic EK recipients; however, the opacity scores were higher and variable in allogeneic EK recipients. Conclusions: These findings establish a standardized protocol to assess the graft outcomes in a murine model of EK. Furthermore, we delineate the underlying immunological pathway that contributes to the immune-mediated rejection of grafts in this model.

Neuropeptide alpha-Melanocyte stimulating hormone preserves corneal endothelial morphology in a murine model of Fuchs dystrophy.

Fuchs endothelial corneal dystrophy is a heterogenous disease with multifactorial etiology, and genetic, epigenetic, and exogenous factors contributing to its pathogenesis. DNA damage plays a significant role, with ultraviolet-A (UV-A) emerging as a key contributing factor. We investigate the potential application of neuropeptide α-melanocyte stimulating hormone (α-MSH) in mitigating oxidative stress induced endothelial damage. First, we examined the effects of α-MSH on a cultured human corneal endothelial cell line (HCEnC-21T) exposed to hydrogen peroxide (H2O2) induced oxidative DNA damage. We performed immunofluorescence and flow cytometry to assess DNA damage and cell death in the cultured cells. Additionally, we used an established mouse model that utilizes ultraviolet light to induce corneal endothelial cell damage resulting in decreased CEnC number, increased cell size variability, and decreased percentage of hexagonal cells. This endothelial decompensation leads to an increase in corneal thickness. Following UV-A exposure, the mice were systemically treated with α-MSH, either immediately after exposure (early treatment) or beginning two weeks post-exposure (delayed treatment). To evaluate treatment efficacy, we analyzed CEnC density and morphology using in vivo confocal microscopy, and central corneal thickness using anterior segment optical coherence tomography. Our findings demonstrated that α-MSH treatment effectively protects HCEnC-21T from free-radical induced oxidative DNA damage and subsequent cell death. In vivo, α-MSH treatment, mitigated the loss of CEnC density, deterioration of cell morphology and suppression of the resultant corneal swelling. These results underline the potential application of α-MSH as a therapeutic agent for mitigating corneal endothelial damage.

Immunopathological mechanisms and clinical manifestations of ocular graft-versus-host disease following hematopoietic stem cell transplantation.

Graft-versus-host disease is among the most common clinical complications following allogeneic hematopoietic stem cell transplantation. It causes inflammation-mediated destruction and dysfunction of various organ systems including ocular tissues in 60-90% of the patients and is termed ocular GVHD (oGVHD). In oGVHD, donor-derived T-cells recognize host antigens as foreign, resulting in immune dysregulation, inflammation and fibrosis of lacrimal glands, meibomian glands, cornea, and conjunctiva. The clinical presentation in oGVHD patients range from mild dry eye symptoms to catastrophic inflammation mediated pathological changes which can cause corneal perforation and blindness. In this review article, we provide detailed insights into the impact of mucosal barrier disruption, the afferent and efferent phases of immunological response involving activation of antigen presenting cells and T cells, respectively. We evaluate the evidence outlining the effector phase of the disease leading to cellular destruction and eventually fibrosis in patients with oGVHD. Finally, we discuss the well-established criteria for the diagnosis of oGVHD.

The Overlooked Floppy Eyelid Syndrome: From Diagnosis to Medical and Surgical Management.

Floppy Eyelid Syndrome (FES) is an underdiagnosed ocular condition characterized by the abnormal laxity of the upper eyelids, often leading to chronic eye irritation and redness. This review provides an in-depth examination of FES, covering its pathophysiology, clinical presentation, and diagnostic and therapeutic approaches. We discuss the potential etiological factors, including genetic predispositions and associations with ocular and systemic conditions such as obesity, obstructive sleep apnea, keratoconus, and glaucoma. Diagnostic strategies are outlined, emphasizing the importance of thorough clinical examinations and specific tests for an efficacious grading and assessment of FES. Management of FES ranges from conservative medical treatments to surgical interventions for more severe cases and should be driven by a comprehensive and multidisciplinary approach. Herein, we illustrate the practical aspects of diagnosing and managing this condition. This comprehensive review aims to enhance the recognition and treatment of FES, ultimately improving the quality of life for affected patients.

Prevalence and Economic Burden of Fuchs Endothelial Corneal Dystrophy in the Medicare Population in the United States.

PURPOSE: The aim of this study was to assess the prevalence and economic burden of Fuchs endothelial corneal dystrophy (FECD) in patients older than 65 years in the United States. METHODS: A retrospective analysis of the Medicare data reported to the Vision and Eye Health Surveillance System including patients diagnosed with FECD between 2014 and 2019 was performed. The crude prevalence rate of FECD was assessed and extrapolated to estimate the total case burden in the United States. The prevalence data were further compared between men and women and different racial groups. In addition, the economic burden was computed using inflation-adjusted direct costs of treatment to patients. RESULTS: The Medicare database included 25,432,700 patients older than 65 years. The national prevalence of FECD in this population cohort was calculated to be 1.12% in 2019. In 2019, FECD case burden in Medicare patients older than 65 years was 284,846 and total estimated FECD case count in the country in this age group was 591,226. FECD prevalence was significantly higher in women as compared to men during the 6-year period evaluated in this study. The intergroup comparison revealed that FECD prevalence in the White population was significantly higher than all other racial groups (P < 0.0001). The total inflation-adjusted economic burden of FECD in the United States in 2019 was USD 291.648 million and has increased from USD 243.998 million over the 6-year study period. CONCLUSIONS: The estimated prevalence of FECD in the individuals older than 65 years is 1.12% in the United States. FECD prevalence is significantly higher in women and White population compared with other ethnicities.

A Novel Murine Model of Endothelial Keratoplasty.

PURPOSE: The purpose of this study was to establish a murine model of endothelial keratoplasty. METHODS: Endothelial keratoplasty (EK) was performed using C57BL/6 donor and BALB/c recipient mice. The central endothelium and Descemet membrane were removed from the recipient cornea, and a 1.5-mm posterior lamellar donor graft was made adherent to the recipient cornea with a small amount of viscoelastic. Mice were followed through slitlamp microscopy postoperatively, and OCT was used to assess the cornea and anterior chamber and measure central corneal thickness. Histology and immunohistochemistry were performed to confirm graft adherence and endothelial cell morphology. RESULTS: Successfully attached EK grafts were visualized in all transplanted animals. Histology and immunostaining confirmed proper graft orientation and adherence, as well as the presence of donor endothelium on transplanted grafts. We observed maximal corneal edema in all animals at day 1 postoperatively which gradually subsided. EK graft survival was 97% at 8 weeks. CONCLUSIONS: In this study, we describe a novel murine model for EK which we anticipate will enable detailed investigation into the cellular and molecular mechanisms involved in EK pathobiology.

Effect of time to operative repair within twenty-four hours on visual acuity outcomes for open globe injuries.

PURPOSE: Convention is to perform open globe injury (OGI) repair within 24 h to minimize risk of endophthalmitis. However, there are limited data assessing how time to operative repair (OR) within 24 h impacts postoperative visual acuity (VA). METHODS: Manual retrospective chart review of 633 eyes at Massachusetts Eye and Ear (MEE) with a diagnosis of OGI between 2012 and 2022. Inclusion criteria were primary repair ≤ 24 h after injury and ≥1 month follow-up. Multivariate regression analysis was conducted with postoperative VA as primary outcome. RESULTS: Of the subjects, 489 (77.3%) were male and 496 (78.4%) were white. Demographics of OGI wounds included 320 (50.6%) rupture and 313 (49.4%) laceration; 126 (19.9%) with rAPD, 189 (29.9%) zone 3 injuries, 449 (71.2%) uveal prolapse, and 110 (17.4%) intraocular foreign body. Final postoperative LogMAR VAs consisted of 31% with a VA < 1.7, 9% with a VA of 1.9, 18% with a VA of 2.3, 27% with a VA of 2.7, and 11% with a VA of 3.0. Multivariate analysis showed no significant correlation between time to OR and postoperative VA (p = 0.800) [95%CI: -0.01,0.01]. Older age (p < 0.001) [95%CI: 0.00,0.01], worse presenting VA (p < 0.001) [95%CI: 0.17,0.32], rAPD (p < 0.001) [95%CI: 0.65,1.0], mechanism of rupture (p < 0.001) [95%CI: 0.19,0.54], higher zone of injury (p < 0.001) [95%CI: 0.25,0.45], and uveal prolapse (p = 0.003) [95%CI: 0.09,0.42] were significantly associated with worse final VA. CONCLUSIONS: Time to repair of OGIs within 24 h does not influence final VA. Optimization of surgical and patient factors may contribute more significantly to final VA than prioritizing more rapid time to OR.

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.

Advances in biomaterials for the treatment of retinoblastoma.

Retinoblastoma is the most common primary intraocular malignancy in children. Although traditional chemotherapy has shown some success in retinoblastoma management, there are several shortcomings to this approach, including inadequate pharmacokinetic parameters, multidrug resistance, low therapeutic efficiency, nonspecific targeting, and the need for adjuvant therapy, among others. The revolutionary developments in biomaterials for drug delivery have enabled breakthroughs in cancer management. Today, biomaterials are playing a crucial role in developing more efficacious retinoblastoma treatments. The key goal in the evolution of drug delivery biomaterials for retinoblastoma therapy is to resolve delivery-associated obstacles and lower nonlocal exposure while ameliorating certain adverse effects. In this review, we will first delve into the historical perspective of retinoblastoma with a focus on the classical treatments currently used in clinics to enhance patients' quality of life and survival rate. As we move along, we will discuss biomaterials for drug delivery applications. Various aspects of biomaterials for drug delivery will be dissected, including their features and recent advances. In accordance with the current advances in biomaterials, we will deliver a synopsis on the novel chemotherapeutic drug delivery strategies and evaluate these approaches to gain new insights into retinoblastoma treatment.