Effect of Methotrexate on an In Vitro Patient-Derived Model of Proliferative Vitreoretinopathy

Recent advances in pharmacological treatments of proliferative vitreoretinopathy

PURPOSE OF REVIEW

Proliferative vitreoretinopathy (PVR) is a severe complication of retinal detachment and trauma, posing significant challenges to surgical success and visual prognosis. Despite advancements in vitreoretinal surgery, PVR incidence remains unchanged, this review presents a synthesis of the principal clinical and preclinical research findings from recent years.

RECENT FINDINGS

Recent research has focused on anti-inflammatory, antiproliferative, and antifibrotic agents. Corticosteroids, such as triamcinolone and dexamethasone, show promise in reducing inflammation but have inconsistent results. Methotrexate and mitomycin C demonstrate efficacy in preclinical and select clinical scenarios. Anti-vascular endothelial growth factor agents and immunotherapies, like infliximab, have shown limited clinical benefits despite promising preclinical data. Novel approaches, including CB2 receptor agonists, exosome-based drug delivery, and nuclear factor kappa B pathway inhibitors, are gaining traction. Additionally, RNA-based and multitargeted therapies highlight the importance of addressing inflammation, fibrosis, and proliferation simultaneously.

SUMMARY

Effective management of PVR requires multifaceted therapies targeting its complex pathogenesis. While current treatments are limited, ongoing research in precision drug delivery and combination therapies offers hope for improved outcomes. Future strategies should focus on translating promising preclinical findings into robust clinical applications.

Postoperative Methotrexate to Reduce Reoperation Rate and Improve Vision in Patients With Complex Retinal Detachments, Advanced Diabetic Retinopathy, and Trauma

Purpose: To identify the potential benefits of postoperative intravitreal (IVT) methotrexate (MTX) for proliferative vitreoretinopathy (PVR), trauma, or advanced diabetic retinopathy (DR). Methods: A retrospective chart review was performed of previously unoperated eyes at high risk for failure as a result of preexisting PVR, trauma, or advanced DR. Patients were included who had retinal detachment (RD) surgery for the following reasons: failed previous retinal reattachment surgery, advanced proliferative DR (PDR), initial surgery for RD associated with trauma, or primary RD associated with grade C PVR. MTX 200 to 400 µg was administered intravitreally at postoperative weeks 1, 2, 4, 7, and 11. Data analyzed included the reoperation rate, visual acuity (VA), physical examination findings, and optical coherence tomography biomarkers. Results: Of the 255 eyes evaluated, 94 received IVT MTX (MTX group) and 161 eyes did not (control group). The mean number of reoperations was 0.39 in the MTX group and 0.94 in the control group (P < .01). The MTX group had a mean gain in VA of 1 line, while the control group had a mean loss of 2.9 lines (P < .01). Conclusions: Postoperative IVT MTX in eyes with advanced PDR or complicated RD yields comparable effective results, including reduced reoperation rates and improved VA.

Dual Application of Methotrexate Improves Functional and Anatomical Outcomes in Diabetic Tractional Retinal Detachment

BACKGROUND AND OBJECTIVE

This study evaluated the use of a dual-delivery methotrexate (MTX) strategy for diabetic tractional retinal detachment (TRD). Diabetic retinopathy (DR) is a leading cause of blindness. Inflammation plays a key role in TRD, and MTX has anti-inflammatory properties.

PATIENTS AND METHODS

This is a pilot study that included 60 patients with TRD. They were block randomized to either MTX with pars plana vitrectomy (PPV) (n = 30) or PPV alone (control, n = 30). MTX was added to the irrigation fluid during surgery and an intra-silicone injection at the end. One month after silicone oil removal, visual acuity (VA), multifocal electroretinography (mfERG), and spectral-domain optical coherence tomography (SD-OCT) were assessed.

RESULTS

One month after silicone oil removal, VA and mfERG were significantly better with a lower prevalence of epiretinal membranes, disorganization of retinal inner layers, and cystic macular changes by SD-OCT in the MTX group.

CONCLUSION

This study found that dual-delivery MTX during PPV is a promising strategy to improve functional and anatomical results in diabetic TRD. [Ophthalmic Surg Lasers Imaging Retina 2025;56:XX-XX.].

Efficacy and safety of methotrexate in the treatment of proliferative vitreoretinopathy: a systematic review

Proliferative Vitreoretinopathy (PVR) is a major complication of surgical repair for Rhegmatogenous Retinal Detachment (RRD). Methotrexate (MTX), a folate antimetabolite, has shown promise in targeting the pathological processes involved in PVR, such as cell proliferation inhibition, fibrosis and anti-inflammation. Systematic review examines the use of MTX in PVR by analysing different administration methods and outcomes. A review of relevant studies from PubMed, EMBASE, and Open Access databases was conducted, focusing on studies investigating the role of MTX in PVR. Study characteristics, patient demographics, dosages, administration frequency, and patient outcomes were extracted. Vitrectomy with various additional procedures such as laser photocoagulation, scleral buckling, gas tamponade and membranectomy were performed during primary and repeated surgery. Among the 180 eyes studied, those receiving MTX through intravitreal injection or intraoperative infusion showed promising outcomes, with retinal reattachment rates ranging from 74 to 92%. Eyes that received MTX infusion intraoperatively had an average retinal reattachment rate of 85%. Improvement in Best Corrected Visual Acuity was also observed in all eyes receiving MTX, with low rates of adverse events reported. Re-operation rates for repeated retinal detachment is significantly lower at 18% for eyes that received MTX treatment compared to those who did not receive MTX at initial surgery. Despite positive findings, further research is needed due to limitations such as small number of studies, low quality of evidence, and heterogeneity in treatment regimens. While MTX shows potential as an adjunctive treatment for PVR in RRD, more robust studies are necessary to confirm its efficacy.

The Possible effect of Bosentan on the methotrexate-induced salivary gland changes in male rats: histological and Immunohistochemical study

Methotrexate (MTX) is an antimetabolite drug utilized for managing a variety of cancers and autoinflammatory conditions. MTX may trigger detrimental effects in mout, h tissues, including salivary gland impairment. Bosentan (BOS), a drug that blocks endothelin receptors, has strengthened antioxidant, anti-inflammatory, and anti-apoptotic properties. The study aimed to estimate the protective effect of BOS on MTX-exacerbated salivary changes in Wistar Albino rats. Thirty male rats were arbitrarily sorted into three groups of ten animals each. The control group received a normal saline for 18 days. The MTX (induction) group received MTX (25 mg/kg) intraperitoneally on the 7th day of the experiment once daily for 6 consecutive days. The MTX + BOS group received BOS (50 mg/kg) orally once a day for 18 days: 6 days before induction, 6 days 2-h after induction, and 6 days post-induction. Animals were euthanized on day 19, and salivary gland tissues were dissected for biochemical, histopathological, and immunohistochemical analyses. BOS dramatically improved MTX-aggravated biochemical and histopathological abnormalities, as evidenced by diminished Bax, caspase 3, TNF-α, IL-1β, MDA, and MPO levels, increased SOD, GSH, and GPX levels, and reduced degenerative changes in the granular convolute tubule, mucous acini, and striate duct. BOS further substantially upregulated MTX-induced decline of the Ki-67 and Bcl-2, as indicated by immunohistochemistry scoring methods. The anti-oxidative, ant-inflammatory, and antiapoptotic properties of BOS are a promising strategy for ameliorating the toxic effect of MTX on submandibular glandular tissues.

Fibrotic Changes in Rhegmatogenous Retinal Detachment

Rhegmatogenous retinal detachment (RRD) is a sight-threatening condition involving retinal detachment and the accumulation of fluid in the subretinal space. Proliferative vitreoretinopathy (PVR) is a pathologic complication that develops after RRD surgery, and approximately 5-10% of RRD cases develop post-operative PVR. Prolonged inflammation in the wound healing process, epithelial-mesenchymal transition (EMT), retinal pigment epithelial (RPE) cell migration and proliferation, and epiretinal, intraretinal, and subretinal fibrosis are typical in the formation of PVR. RPE cells undergo EMT and become fibroblast-like cells that migrate to the retina and vitreous, promoting PVR formation. Fibroblasts transform into myofibroblasts, which promote fibrosis by overproducing the extracellular matrix (ECM). RPE cells, fibroblasts, glial cells, macrophages, T lymphocytes, and increased ECM production form contractile epiretinal membranes. Cytokine release, complement activation, RPE cells, glial cells, and endothelial cells are all involved in retinal immune responses. Normally, wounds heal within 4 to 6 weeks, including hemostasis, inflammation, proliferation, and remodeling phases. Properly initiated inflammation, complement activation, and the function of neutrophils and glial cells heal the wound in the first stage. In a retinal wound, glial cells proliferate and fill the injured area. Gliosis tries to protect the neurons and prevent damage, but it becomes harmful when it causes scarring. If healing is complicated, prolonged inflammation leads to pathological fibrosis. Currently, there is no preventive treatment for the formation of PVR, and it is worth studying in the future.

An mRNA-encoded dominant-negative inhibitor of transcription factor RUNX1 suppresses vitreoretinal disease in experimental models

Messenger RNA (mRNA)-based therapies are a promising approach to medical treatment. Except for infectious diseases, no other disease has mRNA-based therapies available. The eye is an ideal model for mRNA therapeutic development because it requires limited dosing. Proliferative vitreoretinopathy (PVR) is a blinding condition caused by retinal detachment that now lacks available medical treatment, with surgery as the only treatment option. We previously implicated runt-related transcription factor-1 (RUNX1) as a driver of epithelial-to-mesenchymal transition (EMT) in PVR and as a critical mediator of aberrant ocular angiogenesis when up-regulated. On the basis of these findings, an mRNA was designed to express a dominant-negative inhibitor of RUNX1 (RUNX1-Trap). We show that RUNX1-Trap delivered in polymer-lipidoid complexes or lipid nanoparticles sequestered RUNX1 in the cytosol and strongly reduced proliferation in primary cell cultures established from fibrotic membranes derived from patients with PVR. We assessed the preclinical efficacy of intraocular delivery of mRNA-encoded RUNX1-Trap in a rabbit model of PVR and in a laser-induced mouse model of aberrant angiogenesis often used to study wet age-related macular degeneration. mRNA-encoded RUNX1-Trap suppressed ocular pathology, measured as pathological scores in the rabbit PVR model and leakage and lesion size in the laser-induced choroidal neovascularization mouse model. mRNA-encoded RUNX1-Trap also strongly reduced proliferation in a human ex vivo explant model of PVR. These data demonstrate the therapeutic potential of mRNA-encoded therapeutic molecules with dominant-negative properties, highlighting the potential of mRNA-based therapies beyond standard gene supplementation approaches.

Effects of repeated intra-silicone oil injections of methotrexate on proliferative vitreoretinopathy grade C: a multicenter randomized controlled trial

In this randomized controlled trial, we assessed the effects of three consecutive intra-silicone oil (SO) injections of methotrexate (MTX) on the outcomes of surgery for proliferative vitreoretinopathy grade C (PVR-C). Seventy-four eyes of 74 patients with PVR-C were included. Of these, 37 eyes were assigned to the MTX group and 37 eyes to the control group. Fourteen patients failed to comply with the 6-month follow-up period. All eyes underwent vitrectomy and SO injection. In the MTX group, 250 µg MTX was injected into the SO after surgery and at weeks 3 and 6 postoperatively. The primary outcome was the retinal reattachment rate at 6 months. The secondary outcomes included limited PVR recurrence and adverse events. Retinal reattachment was achieved in 22 eyes (73.3%) in the MTX group and 23 eyes (76.7%) in the control group (difference: -3.4%, 95% CI: -25.2-18.5%). Limited PVR recurrence was observed in one eye (4.5%) in the MTX group versus nine eyes (39.1%) in the control group at 6 months (P = 0.01). No adverse effects were observed. Adjunctive treatment with three consecutive applications of intra-SO MTX did not reveal a significant effect on the retinal re-detachment rate but could statistically significantly reduce limited PVR recurrence.Trial registration: http//ClinicalTrials.gov NCT04482543, 22/07/2020.

INTRAVITREAL METHOTREXATE INJECTION FOR THE TREATMENT AND PREVENTION OF PROLIFERATIVE VITREORETINOPATHY

PURPOSE

To report on our experience using intravitreal methotrexate (MTX) in patients with retinal detachment associated with proliferative vitreoretinopathy and/or open globe injury.

METHODS

This study performed a retrospective chart review of a consecutive series of 21 eyes of 21 patients who underwent serial intravitreal MTX injection for treatment and/or prevention of proliferative vitreoretinopathy from December 2021 to January 2024.

RESULTS

Twenty-one patients underwent pars plana vitrectomy, membrane peeling, laser photocoagulation, silicone oil infusion, and intravitreal MTX injection. Postoperatively, all eyes received a series of intravitreal MTX (400 μg/0.1 mL) injections. Optimally, injections were administered weekly for 8 weeks and every 2 weeks for four weeks for a total of 13 injections, beginning intraoperatively at the conclusion of retinal reattachment surgery. Mean baseline preoperative and postoperative visual acuity was logarithm of the minimum angle of resolution 3.2 (approximately hand motions vision) and 2.5 (between CF and hand motions vision), respectively, yielding an average improvement in visual acuity of 0.7 logarithm of the minimum angle of resolution units (0 ETDRS lines/letters). These 21 patients received an average of 10.5 injections. With a single operation, detachments in 19 (90%) of 21 eyes were successfully reattached. Corneal epithelial defects were noted in 7 (33%) of 21 patients.

CONCLUSION

Serial intravitreal MTX injection was associated with 90% single operation retinal reattachment rate in the setting of retinal detachment with proliferative vitreoretinopathy or retinal detachment at high risk of proliferative vitreoretinopathy.

Survey of Dopamine Receptor D2 Antagonists as Retinal Antifibrotics

Purpose: To evaluate the potency and efficacy of a library of dopamine receptor D2 (D2R) antagonists in the mitigation of fibrotic activation in retinal pigment epithelial (RPE) cells. Methods: ARPE-19 cells were cultured and treated with methotrexate or 27 district D2R antagonists using a fibronectin deposition assay. The most potent compounds were then further assessed in assays measuring cellular proliferation, cellular migration, and profibrotic gene expression. Results: The previously established antifibrotic D2R antagonist loxapine exerted a robust and dose-dependent inhibition of fibronectin deposition, whereas methotrexate exerted minimal inhibition. The most potent D2R antagonist identified, fluphenazine, effectively blocked in vitro models of fibrosis at 300-1,000 nM concentrations. Conclusions: Here we found multiple FDA-approved D2R antagonists that potently block RPE cell fibrogenesis. These findings further support the potential of D2R antagonism as a potential therapeutic for retinal fibrotic disease.

THE ROLE OF INTRAVITREAL METHOTREXATE AS AN ADJUNCT TO LOCAL OR SYSTEMIC CORTICOSTEROIDS IN VITRECTOMY FOR RHEGMATOGENOUS RETINAL DETACHMENT AND CHOROIDAL DETACHMENT: A Pilot Study

PURPOSE

To evaluate the role of repeated intravitreal methotrexate as an adjunct to pars plana vitrectomy in the management of rhegmatogenous retinal detachment with choroidal detachment.

METHOD

The authors compared anatomical and visual outcomes of rhegmatogenous retinal detachment with choroidal detachment eyes that underwent pars plana vitrectomy with (Group B) or without repeated intravitreal methotrexate (Group A).

RESULTS

The study included 25 eyes of 25 patients, 16 eyes in Group A and nine in Group B. Both groups had similar baseline characteristics. In Group A, successful retinal attachment was achieved in 50% as compared with 89% in Group B; however, the difference was not statistically significant ( P = 0.08). Also, Group B had a significantly greater change in visual acuity from baseline to the last follow-up visit (1.6 + 1.5 logMAR units) compared with Group A (1.18 + 1 logMAR units) ( P = 0.05). There were no significant safety concerns with the use of intravitreal methotrexate.

CONCLUSION

Repeated intravitreal methotrexate after vitrectomy for rhegmatogenous retinal detachment with choroidal detachment improves outcomes without posing major safety concerns. Nonetheless, further investigation is necessary to establish the optimal intravitreal methotrexate dosage and duration to prevent recurrence effectively.

Proliferative Vitreoretinopathy: Pathophysiology and Therapeutic Approaches

Proliferative vitreoretinopathy (PVR) is a complication of retinal detachment (RD) that is characterized by the development of retinal stiffness and contractile membranes on the surface or underside of the retina. It can occur in primary RD and make repair more challenging, or it can occur following initial successful RD repair and lead to re-detachment. Though our understanding of the pathophysiology underlying PVR membrane formation has grown based on cellular and animal models, there remains no currently approved medical therapy for treatment or prevention of PVR. Though some pharmacologic agents remain under active investigation, many have failed to show consistent benefit in human trials despite promising results from preclinical models. Further research is essential not only to enhance our understanding of PVR pathophysiology but also to identify novel therapeutic strategies for treating PVR in human patients.

Proliferative vitreoretinopathy: an update on the current and emerging treatment options

Proliferative vitreoretinopathy (PVR) remains the main cause of failure in retinal detachment (RD) surgery and a demanding challenge for vitreoretinal surgeons. Despite the large improvements in surgical techniques and a better understanding of PVR pathogenesis in the last years, satisfactory anatomical and visual outcomes have not been provided yet. For this reason, several different adjunctive pharmacological agents have been investigated in combination with surgery. In this review, we analyze the current and emerging adjunctive treatment options for the management of PVR and we discuss their possible clinical application and beneficial role in this subgroup of patients.

Autosomal dominant neovascular inflammatory vitreoretinopathy with CAPN5 c.731T > C gene mutation; clinical management of a family cohort and review of the literature

BACKGROUND

To report a cohort of patients with clinically and genetically diagnosed autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) and showcase the spectrum of the disease utilizing multimodal imaging and genetic testing. Additionally, the utility of multimodal imaging in guiding treatment will also be illustrated.

MATERIALS/METHODS

Five patients from a single-family pedigree in Ohio with clinical signs of ADNIV were evaluated. Medical history, family history, and complete ocular examinations were obtained during regular clinic visits. Multimodal imaging including ocular coherence tomography, fluorescein angiography, wide-field fundus photographs, and Humphrey visual field testing was obtained for all five patients. Additionally, genetic testing for the Calpain-5 (CAPN5) gene was conducted on all patients.

RESULTS

All five patients were noted to have a CAPN5 c.731T > C (p.L244P) mutation on genetic testing. Using multimodal imaging to supplement the clinical examination, pathologic changes such as retinal vascular inflammation, macular edema, and tractional retinal membranes were well illustrated and monitored over time. This allowed for earlier intervention when appropriate such as with intraocular steroid or systemic anti-inflammatory treatments.

CONCLUSION

Phenotypic presentation varied among patients in this series, but is consistent with the spectrum of pathologic changes previously described in patients with other CAPN5 gene mutations. Monitoring of patients with ADNIV utilizing multimodal imaging can help better assess progression of this disease and guide treatment decisions. Additionally, increased genetic testing in patients with inherited retinal diseases may reveal novel gene mutations that could serve as potential targets for future genetic treatment regimens.

RESCUE INTRAVITREAL METHOTREXATE TREATMENT FOLLOWING EARLY RECOGNITION OF PROLIFERATIVE VITREORETINOPATHY

PURPOSE

To report a case of proliferative vitreoretinopathy (PVR) in a man with recurrent retinal detachment successfully managed without surgical intervention following the initiation of intravitreal methotrexate injections to arrest progression of PVR.

METHODS

Report of a case.

RESULTS

A 60-year-old man presented to the retina clinic 4 weeks after undergoing vitrectomy for rhegmatogenous retinal detachment and was found to have an inferior recurrent retinal detachment. He underwent repeat vitrectomy and scleral buckling with successful reattachment of the retina in the immediate postoperative period. At postoperative Week 2, preretinal membranes were noted inferiorly with stretching of the causative retinal break and localized subretinal fluid, consistent with early PVR. The patient underwent immediate laser barricade, and a course of intravitreal methotrexate injections was started. At the final follow-up 7 months later, the retina was fully attached without progression of PVR.

CONCLUSION

Intravitreal methotrexate may play a role in arresting progression of early postoperative PVR and obviating the need for surgical intervention.

In vitro laboratory models of proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR), the most common cause of recurrent retinal detachment, is characterized by the formation and contraction of fibrotic membranes on the surface of the retina. There are no Food and Drug Administration (FDA)-approved drugs to prevent or treat PVR. Therefore, it is necessary to develop accurate in vitro models of the disease that will enable researchers to screen drug candidates and prioritize the most promising candidates for clinical studies. We provide a summary of recent in vitro PVR models, as well as avenues for model improvement. Several in vitro PVR models were identified, including various types of cell cultures. Additionally, novel techniques that have not been used to model PVR were identified, including organoids, hydrogels, and organ-on-a-chip models. Novel ideas for improving in vitro PVR models are highlighted. Researchers may consult this review to help design in vitro models of PVR, which will aid in the development of therapies to treat the disease.

Proliferative Vitreoretinopathy: A Reappraisal

Proliferative vitreoretinopathy (PVR) remains the main cause of failure after retinal detachment (RD) surgery. Despite the development of modern technologies and sophisticated techniques for the management of RD, the growth of fibrocellular membranes within the vitreous cavity and on both sides of the retinal surface, as well as intraretinal fibrosis, can compromise surgical outcomes. Since 1983, when the term PVR was coined by the Retina Society, a lot of knowledge has been obtained about the physiopathology and risk factors of PVR, but, despite the proposal of a lot of therapeutic challenges, surgical skills seem to be the only effective way to manage PVR complications.

Using Advanced Bioinformatics Tools to Identify Novel Therapeutic Candidates for Proliferative Vitreoretinopathy

Purpose

Proliferative vitreoretinopathy (PVR) is the dreaded cause of failure following retinal detachment repair; however, no cures or preventative therapies exist to date. The purpose of this study was to use bioinformatics tools to identify drugs or compounds that interact with biomarkers and pathways involved in PVR pathogenesis that could be eligible for further testing for the prevention and treatment of PVR.

Methods

We queried PubMed to compile a comprehensive list of genes described in PVR to date from human studies, animal models, and genomic studies found in the National Center for Biotechnology Information database. Gene enrichment analysis was performed using ToppGene on PVR-related genes against drug-gene interaction databases to construct a pharmacome and estimate the statistical significance of overrepresented compounds. Compounds with no clinical indications were filtered out from the resulting drug lists.

Results

Our query identified 34 unique genes associated with PVR. Out of 77,146 candidate drugs or compounds in the drug databases, our analysis revealed multiple drugs and compounds that have significant interactions with genes involved in PVR, including antiproliferatives, corticosteroids, cardiovascular agents, antioxidants, statins, and micronutrients. Top compounds, including curcumin, statins, and cardiovascular agents such as carvedilol and enalapril, have well-established safety profiles and potentially could be readily repurposed for PVR. Other significant compounds such as prednisone and methotrexate have shown promising results in ongoing clinical trials for PVR.

Conclusions

This bioinformatics approach of studying drug-gene interactions can identify drugs that may affect genes and pathways implicated in PVR. Predicted bioinformatics studies require further validation by preclinical or clinical studies; however, this unbiased approach could identify potential candidates among existing drugs and compounds that could be repurposed for PVR and guide future investigations.

Translational Relevance

Novel repurposable drug therapies for PVR can be found using advanced bioinformatics models.

Aerosolized, Gas-Phase, Intravitreal Methotrexate Reduces Proliferative Vitreoretinopathy in a Randomized Trial in a Porcine Model

Purpose

To determine the effectiveness of aerosol-delivered methotrexate (AD-MTx) in a large-animal (porcine) model of proliferative vitreoretinopathy (PVR).

Design

Prospective, randomized, interventional, double-masked, controlled, large-animal study with predetermined clinical and histopathologic outcome criteria.

Controls

Half of the pigs were randomly assigned to receive an identical volume of aerosol-delivered normal saline (AD-NS) using identical delivery systems and treatment intervals.

Methods

Proliferative vitreoretinopathy was surgically induced in 16 pigs (8 males and 8 females), randomly assigned to receive 2 doses (group A) or 3 doses (group B) of either AD-MTx (1.6 mg/0.4 ml) or normal saline (AD-NS). Group A pigs were euthanized at week 2 (n = 8), and group B pigs were euthanized at week 3 (n = 8). Masked clinical PVR scores (0-6) by a vitreoretinal surgeon and histopathology PVR scores (0-8) by a masked ophthalmic pathologist were used to determine outcomes.

Main Outcome Measures

The mean, combined clinical and histopathology scores (both anterior and posterior) were used to determine the overall treatment effect between the groups.

Results

The mean masked score (± standard deviation) when all grading end points (clinical + histopathology) were combined was a mean of 8.0 ± 2.3 in the AD-MTx group versus a higher 9.9 ± 2.0 in the AD-NS control group (P = 0.05). The clinical score was 3.88 ± 1.2 in the AD-MTx group versus 4.63 ± 1.6 in the AD-NS group (P = 0.16). The histopathology score for anterior PVR was 2.5 ± 0.8 in the AD-MTx group versus 2.5 ± 0.5 in the AD-NS group (P = 0.50), and the posterior PVR was 1.63 ± 1.6 in the AD-MTx group versus 2.75 ± 1.3 in the AD-NS group (P = 0.07). When the frequency of methotrexate dosing in group A (2 doses) was compared with that in group B (3 doses), the mean score was 8.75 versus 9.13 (P = 0.38), respectively, suggesting an insignificant difference.

Conclusions

After surgical induction of PVR in an aggressive, high-risk, large-animal model, AD-MTx reduced posterior PVR formation compared with AD-NS. Additional dosing at week 3 did not improve the outcomes. No difference in anterior PVR formation was noted with intervention. This novel drug delivery system has implications for PVR reduction and warrants further investigation.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Experimental Models to Study Epithelial-Mesenchymal Transition in Proliferative Vitreoretinopathy

Proliferative vitreoretinal diseases (PVDs) encompass proliferative vitreoretinopathy (PVR), epiretinal membranes, and proliferative diabetic retinopathy. These vision-threatening diseases are characterized by the development of proliferative membranes above, within and/or below the retina following epithelial-mesenchymal transition (EMT) of the retinal pigment epithelium (RPE) and/or endothelial-mesenchymal transition of endothelial cells. As surgical peeling of PVD membranes remains the sole therapeutic option for patients, development of in vitro and in vivo models has become essential to better understand PVD pathogenesis and identify potential therapeutic targets. The in vitro models range from immortalized cell lines to human pluripotent stem-cell-derived RPE and primary cells subjected to various treatments to induce EMT and mimic PVD. In vivo PVR animal models using rabbit, mouse, rat, and swine have mainly been obtained through surgical means to mimic ocular trauma and retinal detachment, and through intravitreal injection of cells or enzymes to induce EMT and investigate cell proliferation and invasion. This review offers a comprehensive overview of the usefulness, advantages, and limitations of the current models available to investigate EMT in PVD.

Myo/Nog Cells Give Rise to Myofibroblasts During Epiretinal Membrane Formation in a Mouse Model of Proliferative Vitreoretinopathy

Purpose

Myo/Nog cells are the source of myofibroblasts in the lens and synthesize muscle proteins in human epiretinal membranes (ERMs). In the current study, we examined the response of Myo/Nog cells during ERM formation in a mouse model of proliferative vitreoretinopathy (PVR).

Methods

PVR was induced by intravitreal injections of gas and ARPE-19 cells. PVR grade was scored by fundus imaging, optical coherence tomography, and histology. Double label immunofluorescence localization was performed to quantify Myo/Nog cells, myofibroblasts, and leukocytes.

Results

Myo/Nog cells, identified by co-labeling with antibodies to brain-specific angiogenesis inhibitor 1 (BAI1) and Noggin, increased throughout the eye with induction of PVR and disease progression. They were present on the inner surface of the retina in grades 1/2 PVR and were the largest subpopulation of cells in grades 3 to 6 ERMs. All α-SMA-positive (+) cells and all but one striated myosin+ cell expressed BAI1 in grades 1 to 6 PVR. Folds and areas of retinal detachment were overlain by Myo/Nog cells containing muscle proteins. Low numbers of CD18, CD68, and CD45+ leukocytes were detected throughout the eye. Small subpopulations of BAI1+ cells expressed leukocyte markers. ARPE-19 cells were found in the vitreous but were rare in ERMs. Pigmented cells lacking Myo/Nog and muscle cell markers were present in ERMs and abundant within the retina by grade 5/6.

Conclusions

Myo/Nog cells differentiate into myofibroblasts that appear to contract and produce retinal folds and detachment. Targeting BAI1 for Myo/Nog cell depletion may be a pharmacological approach to preventing and treating PVR.

Rhegmatogenous retinal detachment surgery: A review

Rhegmatogenous retinal detachment (RRD) is a serious surgical condition with significant ocular morbidity if not managed properly. Once untreatable, approaches to the repair of RRD have greatly evolved over the years, leading to outstanding primary surgical success rates. The management of RRD is often a topic of great debate. Scleral buckling, vitrectomy and pneumatic retinopexy have been used successfully for the treatment of RRD. Several factors may affect surgical success and dictate a surgeon's preference for the technique employed. In this review, we provide an overview and supporting literature on the options for RRD repair and their respective preoperative and postoperative considerations in order to guide surgical management.

Intraocular Methotrexate for the Treatment and Prevention of Proliferative Vitreoretinopathy: A Review

Purpose:

To review the current literature on the use of intravitreal methotrexate (IVT MTX) for the treatment and prevention of proliferative vitreoretinopathy (PVR).

Methods:

All reports of IVT MTX to treat and prevent PVR published in PubMed, Google Scholar, and EBSCOhost were reviewed. The relevant current studies are included in this report.

Results:

The literature search yielded 32 articles describing the use of MTX in PVR. These included preclinical studies, 1 case report, and several case series. Early studies found that IVT MTX is a promising medication for the treatment and prevention of PVR. MTX works as a potent anti-inflammatory agent through a new mechanism of action different from that of other medications for use in PVR. Few side effects have been reported and were mostly limited to mild reversible corneal keratopathy. There are 2 current ongoing randomized controlled clinical trials to further evaluate the efficacy of MTX for PVR.

Conclusions:

MTX is a safe and potentially efficacious medication for the treatment and prevention of PVR. Additional clinical trials are needed to further establish this effect.

Intravitreal methotrexate infusion for prophylaxis of proliferative vitreoretinopathy after pars plana vitrectomy for rhegmatogenous retinal detachment

Background

Proliferative vitreoretinopathy (PVR) is the leading cause of recurrent retinal detachment after surgical repair of rhegmatogenous retinal detachment (RRD). Our study aimed to assess the efficacy and safety of intravitreal methotrexate infusion (IMI) for the prevention of PVR after pars plana vitrectomy (PPV) in eyes with RRD.

Methods

This prospective comparative interventional study was conducted from September 2020 to November 2021 at Ain Shams University Hospitals, Egypt. We recruited a consecutive, non-randomized sample of 47 eyes of 47 patients with RRD undergoing PPV. Participants were allocated to a control group or an intervention group that received IMI during surgery. Each group was subdivided into subgroups of eyes at high-risk of developing PVR and eyes with established preoperative PVR grade C. Outcome measures at the 3-month postoperative follow-up were the rate of retinal attachment, incidence of PVR, reoperation rate to flatten the retina, and changes in the retina and/or optic nerve function as assessed by full-field electroretinogram and flash visual evoked potential.

Results

Data from 47 eyes (23 and 24 eyes in the intervention and control groups, respectively) were evaluated. Subgroups IA, IB, and IIB each included 12 eyes, subgroup IIA included 11 eyes, and all subgroups had comparable sex ratios and age distributions. Postoperative PVR at 1 month and between 1 and 3 months was present in 13% and 4% of eyes in the intervention group, respectively. Reoperation to flatten the retina was required in 2 (9%) eyes in the intervention group, while 22 eyes (96%) had complete flattening of the retina at 3 months. No significant differences were found between the study groups and the corresponding subgroups regarding the outcome measures (all P > 0.05). No adverse events attributable to IMI were detected up to 3 months postoperatively.

Conclusions

Although IMI was safe for intraocular use in eyes with RRD and PVR grade C or a high risk of developing PVR, it did not affect the anatomical success rate or development of PVR up to 3 months after PPV. Further multicenter randomized clinical trials with longer follow-up periods and larger sample sizes are needed to verify these preliminary outcomes.

Advances in Vitreoretinal Surgery

Advances in vitreoretinal surgery provide greater safety, efficacy, and reliability in the management of the several vitreoretinal diseases that benefit from surgical treatment. The advances are divided into the following topics: scleral buckling using chandelier illumination guided by non-contact visualization systems; sclerotomy/valved trocar diameters; posterior vitrectomy systems and ergonomic vitrectomy probes; chromovitrectomy; vitreous substitutes; intraoperative visualization systems including three-dimensional technology, systems for intraoperative optical coherence tomography, new instrumentation in vitreoretinal surgery, anti-VEGF injection before vitrectomy and in eyes with proliferative diabetic retinopathy, and new surgical techniques; endoscopic surgery; the management of subretinal hemorrhages; gene therapy; alternative techniques for refractory macular hole; perspectives for stem cell therapy and the prevention of proliferative vitreoretinopathy; and, finally, the Port Delivery System. The main objective of this review is to update the reader on the latest changes in vitreoretinal surgery and to provide an understanding of how each has impacted the improvement of surgical outcomes.

Outcomes and Prognostic Factors Following Pars Plana Vitrectomy for Intraocular Foreign Bodies-11-Year Retrospective Analysis in a Tertiary Care Center

Aim: To evaluate the visual outcome of penetrating ocular injuries with a retained intraocular foreign body (IOFB) managed by pars plana vitrectomy (PPV) and to describe the risk factors associated with poor visual acuity and retinal detachment (RD) development. Methods: Medical records of 56 patients with IOFB that were removed by PPV over a period of 11 years (1 January 2010−31 December 2020) were reviewed. We extracted the demographic data, initial and final best corrected visual acuity (BCVA) using standard Snellen chart, IOFB characteristics, complications and surgical details. Outcome was evaluated according to the final BCVA: poor <0.1, good 0.1−<0.5 or excellent ≥0.5. Results: The mean age was 36.1 ± 14.1 (range, 16−71) years and the majority of patients were males (55 out of 56, 98.2%). IOFB was retinal in 27 (48.2%) cases and intravitreal in 29 cases (51.8%). IOFB size was ≤3mm in 26 (46.4%) cases and >3mm in 30 (53.6%) cases. Preoperative RD was identified in 12 (21.4%) cases and endophthalmitis in 17 cases (30.4%). IOFBs larger than 3 mm and retinal location were associated with RD development. Poor visual outcome was associated with initial BCVA, retinal location, RD and endophthalmitis. Conclusion: Initial BCVA, retinal foreign body, RD and endophthalmitis were risk factors for poor visual outcome.

Single-Cell Protein and Transcriptional Characterization of Epiretinal Membranes From Patients With Proliferative Vitreoretinopathy

Purpose

Proliferative vitreoretinopathy (PVR) remains an unresolved clinical challenge and can lead to frequent revision surgery and blindness vision loss. The aim of this study was to characterize the microenvironment of epiretinal PVR tissue, in order to shed more light on the complex pathophysiology and to unravel new treatment options.

Methods

A total of 44 tissue samples were analyzed in this study, including 19 epiretinal PVRs, 13 epiretinal membranes (ERMs) from patients with macular pucker, as well as 12 internal limiting membranes (ILMs). The cellular and molecular microenvironment was assessed by cell type deconvolution analysis (xCell), RNA sequencing data and single-cell imaging mass cytometry. Candidate drugs for PVR treatment were identified in silico via a transcriptome-based drug-repurposing approach.

Results

RNA sequencing of tissue samples demonstrated distinct transcriptional profiles of PVR, ERM, and ILM samples. Differential gene expression analysis revealed 3194 upregulated genes in PVR compared with ILM, including FN1 and SPARC, which contribute to biological processes, such as extracellular matrix (ECM) organization. The xCell and IMC analyses showed that PVR membranes were composed of macrophages, retinal pigment epithelium, and α-SMA-positive myofibroblasts, the latter predominantly characterized by the co-expression of immune cell signature markers. Finally, 13 drugs were identified as potential therapeutics for PVR, including aminocaproic acid and various topoisomerase-2A inhibitors.

Conclusions

Epiretinal PVR membranes exhibit a unique and complex transcriptional and cellular profile dominated by immune cells and myofibroblasts, as well as a variety of ECM components. Our findings provide new insights into the pathophysiology of PVR and suggest potential targeted therapeutic options.

Translational and clinical advancements in management of proliferative vitreoretinopathy

PURPOSE OF REVIEW

Despite advancement in the surgical instrumentation and techniques, proliferative vitreoretinopathy (PVR) remains the most common cause for failure of rhegmatogenous retinal detachment (RRD) repair. This review discusses ongoing translational and clinical advancements in PVR.

RECENT FINDINGS

PVR represents an exaggerated and protracted scarring process that can occur after RRD. The primary cell types involved are retinal pigment epithelium, glial, and inflammatory cells. They interact with growth factors and cytokines derived from the breakdown of the blood-retinal barrier that trigger a cascade of cellular processes, such as epithelial-mesenchymal transition, cell migration, chemotaxis, proliferation, elaboration of basement membrane and collagen and cellular contraction, leading to overt retinal pathology. Although there are currently no medical therapies proven to be effective against PVR in humans, increased understanding of the risks factors and pathophysiology have helped guide investigations for molecular targets of PVR. The leading therapeutic candidates are drugs that mitigate growth factors, inflammation, and proliferation are the leading therapeutic candidates.

SUMMARY

Although multiple molecular targets have been investigated to prevent and treat PVR, none have yet demonstrated substantial evidence of clinical benefit in humans though some show promise. Advancements in our understanding of the pathophysiology of PVR may help develop a multipronged approach for this condition.

Complications of intravitreal injections: 2022

PURPOSE OF REVIEW

This review highlights the complications of both intravitreal injection procedure as well as different intravitreal medications including antivascular endothelial growth factors, antibiotics, antivirals, antifungals, methotrexate, and steroids. Techniques for reducing rates of endophthalmitis will also be discussed.

RECENT FINDINGS

Intravitreal vancomycin can cause hemorrhagic occlusive retinal vasculitis resulting in severe vision loss. Intravitreal brolucizumab is associated with intraocular inflammation and retinal vasculitis resulting in significant vision loss. Face mask use by both patient and physician is not associated with increased risk of endophthalmitis and may decrease culture positive endophthalmitis.

SUMMARY

Intravitreal injections continue to be one of the most commonly performed procedures by ophthalmologists. Although the injections are generally well tolerated, sight-threatening complications can occur including endophthalmitis, retinal detachment, and/or retinal vasculitis. Adverse events associated with specific medications are outlined below. Several safety measures have been shown to reduce rates of endophthalmitis, the most concerning complication of this procedure.

Long-Term Outcomes and Risk Factors for Severe Vision Loss in Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy (ADNIV)

Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a rare disorder characterized by uveitis, retinal neovascularization, and retinal degeneration. We sought to describe the course of treated and untreated ADNIV and to identify risk factors for severe vision loss.

DESIGN

Observational case series.

METHODS

Clinical data from ADNIV patients from 4 families seen from 1967 through 2019 at a single academic, tertiary referral center were reviewed. The main outcome measures were visual acuity at baseline and follow-up, as well as risk factors for vision loss.

RESULTS

A total of 130 eyes from 65 ADNIV patients (45 female, 20 male; mean age 40.8 years, range 6-77 years) were included. Mean best corrected visual acuity (BCVA) at presentation was LogMAR 0.59 (about Snellen 20/80). Longitudinal analysis included 84 eyes from 42 patients (31 female, 11 male), with mean follow-up of 17.3 years (range 2-43.6 years). Mean BCVA at last follow-up was LogMAR 1.48 (about Snellen 20/600). The disease accelerated in the fifth decade of life, during which the majority of eyes went from normal vision or mild vision loss to at least moderate vision loss (20/70 Snellen equivalent); 25 eyes from 16 patients (29.8%;) showed a steep trajectory of vision loss to no light perception. Tractional retinal detachment was the greatest risk factor for severe vision loss (BCVA <20/200) on multivariable analysis (P < .05).

CONCLUSIONS

Patients with ADNIV have a high lifetime risk of severe vision loss. Tractional retinal detachment is an important risk factor for poor vision.

Intravitreal Methotrexate for Recalcitrant Epiretinal Membrane Reproliferation

This article reports a case of a 65-year-old woman with recalcitrant recurrent epiretinal membrane (ERM) treated with revision vitrectomy and membrane peeling followed by 12 weekly intravitreal methotrexate injections. Visual acuity and central macular thickness significantly improved, and no ERM recurrence developed 7 months after surgery. This case represents the first documented use of methotrexate to treat surgically resistant ERM reproliferation and indicates a potential for its use in cases that do not respond to standard treatment. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:49-51.].

Comparative cytotoxic and antiproliferative profile of methotrexate and fluorouracil on different ocular cells

PURPOSE

To analyse the cytotoxic and antiproliferative effect of methotrexate (MTX) and fluorouracil (5-FU) in vitro on fibroblasts, retinal pigment epithelial (RPE) and photoreceptor cells as an adjunct for reducing the incidence of proliferative vitreoretinopathy (PVR) after rhegmatogenous retinal detachment surgery.

METHODS

Methotrexate and 5-FU were dissolved separately in balanced salt solution (BSS) with concentrations ranging from 0-8000 µg/ml and 0-4000 µg/ml, respectively. All solutions were analysed in terms of pH and osmolarity and applied for 1 h to fibroblasts (BJ), RPE (ARPE-19) and photoreceptor (661W) cell lines adherently cultivated in 96-well cell culture plates (10 000 cells/well). 24 h after incubation, the proliferative (BrdU), metabolic (CellTiter-Glo) and apoptotic (Caspase 3/7) activity of the cells were examined in vitro.

RESULTS

5-FU had an antiproliferative effect on BJ and ARPE-19 cells starting from low concentrations (2 µg/ml). However, the viability of 661W cells decreased and apoptosis was induced with increasing 5-FU concentration. In contrast, MTX up to a concentration of 266 µg/ml did neither result in a significant loss of viability nor in increased caspase 3/7 activity of BJ, ARPE-19 and 661W cells and inhibited the proliferation of ARPE-19 already at low concentrations starting from 8 µg/ml.

CONCLUSIONS

Methotrexate dissolved in BSS is biocompatible up to a concentration of 266 µg/ml and may act as an intraoperative rinse solution to inhibit RPE proliferation in PVR-diseased eyes. Contrary, the use of 5-FU within the posterior segment of the eye is limited by its cell-damaging effect on photoreceptor cells.

Use of Intravitreal Methotrexate Infusion in Complicated Retinal Detachment for Prevention of Proliferative Vitreoretinopathy in a Pilot Study

Objective

The objective of this pilot study was to evaluate the efficacy and safety of per-operative intravitreal methotrexate (MTX) infusion during vitrectomy in patients of retinal detachment (RD) with advanced grade proliferative vitreoretinopathy (PVR).

Methods

In this prospective interventional case series, we included patients with Grade C PVR, recurrent RD, and open globe trauma. All patients underwent standard single surgeon operated 23-gauge pars plana vitrectomy (PPV) with 80mg of MTX in 1000mL of irrigation fluid. All patients were followed up after four months to assess the final status of retinal attachment and visual acuity. Ethical review board permission was sought for this off-label use of MTX and all patients signed an informed consent form before this intervention.

Results

Thirty eyes of 30 patients with recurrent retinal detachment, open globe trauma, or grade C PVR at initial presentation were included in this study. After PPV, these patients were followed up after four months. A total of 24 (80%) patients maintained retinal attachment at four months. Mean preoperative best-corrected visual acuity (BCVA) was 1.35 logarithm of the minimum angle of resolution (logMAR) (range 0.5-3) and mean four months postoperative BCVA was 1.01 logMAR (range 0.3-3) (Student’s t-test; P-value <0.05). Seventeen (56.6%) eyes had pre-operative BCVA of 1.0 whereas 25 (83.3%) had BCVA of 1.0 at the end of the follow-up period. Six (20%) patients had preoperative BCVA of 0.7 whereas 12 (40%) patients had BCVA of 0.7 at four months postoperatively. Out of six (20%) eyes developing RD after this intervention, four eyes achieved retinal reattachment after a second surgery. We did not observe any MTX-related complications during the follow-up period of this study.

Conclusion

Intravitreal MTX infusion during PPV for complicated RD as an adjunctive therapy showed encouraging results and was found to be safe in its use. We need more rigorous and controlled studies to confirm the possible advantages of MTX and its role in the prevention of PVR.

Anatomical and Functional Outcomes of Vitrectomy with/without Intravitreal Methotrexate Infusion for Management of Proliferative Vitreoretinopathy Secondary to Rhegmatogenous Retinal Detachment

Purpose

To assess the anatomical and functional outcomes of intravitreal infusion of methotrexate (MTX) during pars plana vitrectomy (PPV) for proliferative vitreoretinopathy (PVR) associated with rhegmatogenous retinal detachment (RRD).

Methods

Comparative interventional nonrandomized study including consecutive patients who had vitrectomy for RRD. The study included six groups. Groups I (established PVR), II (high risk of PVR), and III (no risk of PVR) comprised prospectively recruited study eyes, which received PPV and adjuvant intravitreal MTX infusion equivalent to 400 μg/0.1 mL. Groups IA, IIA, and IIIA comprised retrospectively recruited control groups. Main outcome measures were retinal reattachment at the end of 6 months, visual outcome, and complications. Chi-square test or Fisher's exact test analyzed categorical variables. ANOVA test and Kruskal-Wallis test analyzed quantitative variables. Mann-Whitney U-test and independent t-test evaluated the difference between each group and its control. Comparison between two paired groups was done by Wilcoxon Rank test. The Kaplan-Meier method was used for survival analysis and the log-rank test estimated differences in event-free survival across the groups. P was significant at <0.05.

Results

The study included 190 eyes of 188 patients. Study Groups I, II, and III included 42, 35, and 24 eyes, respectively. Mean age was 45 years. Male gender constituted 70% of patients. Mean follow-up period was 6 months. Control Groups IA, IIA, and IIIA included 30, 30, and 29 eyes, respectively. Mean age was 50 years. Male gender constituted 50%. Mean follow-up period was 7 months. Median rate of retinal reattachment was 82% in the study eyes versus 86% in the control eyes. The difference in the retinal reattachment rates between each study group and its respective control was not statistically significant, Group I-IA (p= 0.2), Group II-IIA (p=0.07), and Group III-IIIA (p=0.07). BCVA improved by a mean of 4 lines in the study eyes versus 3 lines in the control eyes. The difference in visual outcome between each study group and its respective control was statistically significant between Groups II-IIA and III-IIIA, p=0.03, but not between Groups I-IA, p=0.07. We did not detect complications attributed to MTX use in the study eyes.

Conclusion

Intravitreal infusion of MTX during PPV is a safe adjuvant therapy in RRD patients with and without PVR. MTX yields superior functional outcomes in patients at high risk of PVR and in patients with no risk of PVR compared to PPV without MTX, but not in cases with established PVR. MTX did not confer an additional advantage in terms of retinal reattachment rate. Summary. Proliferative vitreoretinopathy is a major cause of failure in surgery for rhegmatogenous retinal detachment. Methotrexate as an adjuvant therapy blocks essential drivers in the pathogenetic cascade leading to PVR. Intravitreal infusion has the advantage of blocking the pathology in its nascence and obviates the need for repeated intravitreal injections of the drug.

The Proteome of Preretinal Tissue in Proliferative Vitreoretinopathy

BACKGROUND AND OBJECTIVE

Proliferative vitreoretinopathy (PVR) is the leading cause of retinal detachment repair failure. However, the molecular pathogenesis remains incompletely understood. Determining the proteome of PVR will help to identify novel therapeutic targets.

MATERIALS AND METHODS

Preretinal tissue samples, delaminated during surgery from six PVR cases and one idiopathic epiretinal membrane (ERM) were analyzed by mass spectrometry. Tandem mass spectra were extracted using the UniProt database, generating a list of 896 proteins, which were subjected to pathway set and fold-change (ERM vs PVR) analyses.

RESULTS

Two pathways were enriched in PVR: extracellular matrix (ECM) organization and extracellular structure organization. A fold-change analysis comparing mean total spectral counts from PVR to an ERM control identified fibronectin, the ECM glycoprotein, as the protein most significantly elevated in PVR compared to ERM.

CONCLUSION

These data identify pathwayskey to PVR progression, including thoseinvolved in cell-mediated ECM assembly and thus tractional force generation at the cellular level. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:S5-S12.].

Adjunctive serial post-operative intravitreal methotrexate injections in the management of advanced proliferative vitreoretinopathy

PURPOSE

To assess the effects of weekly post-operative intravitreal methotrexate injections on eyes with grade C proliferative vitreoretinopathy (PVR) that underwent surgical repair.

METHODS

Retrospective case-control study of 16 eyes with retinal detachment and grade C PVR. Seven eyes received weekly intravitreal MTX injections post-operatively as an adjunct and 9 eyes served as the control. The main outcome measure was the retinal re-attachment rate.

RESULTS

In the MTX group, 86% (6/7) of eyes had a complete retinal re-attachment at the end of the follow-up period. In contrast in the no MTX group, only 22.2% (2/9) of eyes had a complete retinal re-attachment (p = 0.0406). The patients in the MTX group received a mean of 6 injections (range 4-8). There were no cases of corneal epitheliopathy.

CONCLUSIONS

Serial intravitreal MTX as an adjunct to surgical repair holds promise for the management of PVR.

Molecular Targets for Proliferative Vitreoretinopathy

While innovations in the surgical management of retinal detachment (RD) with proliferative vitreoretinopathy (PVR) have significantly improved anatomic and visual outcomes over the years, recurrent RD due to PVR remains the major limitation to success. There are currently no medical therapies proven to be effective against PVR in humans. Increased understanding of the pathophysiology and risk factors for PVR have helped guide investigations for molecular targets. Drugs that counteract inflammation, proliferation, and growth factors are the leading candidates for treatment of PVR. This review discusses the ongoing search for pharmacologic therapies, with an emphasis on the results of recent clinical investigations.

[Proliferative vitreoretinopathy prophylaxis : Mission (im)possible]

BACKGROUND

Proliferative vitreoretinopathy (PVR) is one of the most important complications following vitreoretinal surgery. So far, surgical strategies have been the gold standard in treatment. Pharmacological approaches for prevention and treatment of PVR are under clinical investigation and intervene in different phases of the PVR cascade.

METHODS

The relevant literature as well as own data and experience with PVR are discussed in this review article. The most important aspects of pharmacological approaches for PVR prophylaxis and treatment are explained.

RESULTS

A prophylactic use of systemic prednisone administration as an anti-inflammatory substance showed contradictory results, while there was no additional benefit for intravitreal triamcinolone. Orally administered isotretinoin also seems to be able to minimize the formation of PVR after retinal reattachment surgery, whereas there was no improvement in the success rate in established PVR. Cell proliferation inhibitors have already been extensively studied. The combined intravitreal prophylactic approach of 5‑fluorouracil and low molecular weight heparin was recently further investigated in a multicenter, placebo-controlled study and showed a positive effect in some studies. New preclinical and experimental approaches include the inhibition of growth factors, modulation of integrin activity and the induction of apoptosis.

CONCLUSION

Most clinical studies dealt with an anti-inflammatory or antiproliferative approach. So far, no pharmacological substance has been established for the treatment of PVR but there are promising approaches for prophylaxis.

Eye Diseases Direct Interest to Complement Pathway and Macrophages as Regulators of Inflammation in COVID-19

ABSTRACT

Many of the risk factors for developing severe coronavirus disease 2019 (COVID-19) are also risk factors for eye diseases such as age-related macular degeneration (AMD). During the past decades, macrophages and the complement pathway (as a part of the innate immune system) have been identified as important contributors to the development of AMD, and we suggest that these mechanisms are of similar importance for the clinical course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Based on the experience with AMD, we discuss how behavioral factors such as diet, smoking and higher body mass index, as well as genetic determinants such as the complement and immune pathway genes may lead to the overactive inflammatory phenotypes seen in some patients with COVID-19, and may in part explain the heterogeneity of disease manifestations and outcomes. Based on this experience, we discuss potential genetic research projects and elaborate on preventive and treatment approaches related to COVID-19.

Topical delivery of a small molecule RUNX1 transcription factor inhibitor for the treatment of proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) is the leading cause of retinal detachment surgery failure. Despite significant advances in vitreoretinal surgery, it still remains without an effective prophylactic or therapeutic medical treatment. After ocular injury or retinal detachment, misplaced retinal cells undergo epithelial to mesenchymal transition (EMT) to form contractile membranes within the eye. We identified Runt-related transcription factor 1 (RUNX1) as a gene highly expressed in surgically-removed human PVR specimens. RUNX1 upregulation was a hallmark of EMT in primary cultures derived from human PVR membranes (C-PVR). The inhibition of RUNX1 reduced proliferation of human C-PVR cells in vitro, and curbed growth of freshly isolated human PVR membranes in an explant assay. We formulated Ro5-3335, a lipophilic small molecule RUNX1 inhibitor, into a nanoemulsion that when administered topically curbed the progression of disease in a novel rabbit model of mild PVR developed using C-PVR cells. Mass spectrometry analysis detected 2.67 ng/mL of Ro5-3335 within the vitreous cavity after treatment. This work shows a critical role for RUNX1 in PVR and supports the feasibility of targeting RUNX1 within the eye for the treatment of an EMT-mediated condition using a topical ophthalmic agent.

Apremilast Regulates the Teff/Treg Balance to Ameliorate Uveitis via PI3K/AKT/FoxO1 Signaling Pathway

Autoimmune uveitis (AU), being one of the sight-threatening ocular inflammatory disorders, has been widely regarded by ophthalmologists and immunologists as a great challenge. Apremilast, a phosphodiesterase-4 inhibitor (PDE4i), which was approved by the U.S. Food and Drug Administration (FDA) for the treatment of active psoriatic arthritis in 2014, has been attracting researchers, who are exploring its efficiency and mechanism on uveitis. In this study, we used an experimental autoimmune uveitis (EAU), a representative model for human AU, to investigate the effect of apremilast on regulating anti-inflammatory mediators. Our study demonstrated that apremilast treatment resulted in a decrease in vascular leakage, macular edema, and inflammatory cell infiltration in the retina, corresponding to decreased clinical and pathological scores. Specifically, apremilast decreased the proportion and population of Th17 cells and increased the proportion and population of T regulatory (Treg) cells. Mechanistically, apremilast may regulate Th17 and Treg cells by inhibiting the phosphorylation of the phosphoinositide 3-kinase (PI3K)/protein kinase B(AKT)/Forkhead box O1 (FoxO1) signaling pathway. These findings suggested that apremilast alleviated EAU by regulating Th17 and Treg through the PI3K/AKT/FoxO1 pathway.

Polarity and epithelial-mesenchymal transition of retinal pigment epithelial cells in proliferative vitreoretinopathy

Under physiological conditions, retinal pigment epithelium (RPE) is a cellular monolayer composed of mitotically quiescent cells. Tight junctions and adherens junctions maintain the polarity of RPE cells, and are required for cellular functions. In proliferative vitreoretinopathy (PVR), upon retinal tear, RPE cells lose cell-cell contact, undergo epithelial-mesenchymal transition (EMT), and ultimately transform into myofibroblasts, leading to the formation of fibrocellular membranes on both surfaces of the detached retina and on the posterior hyaloids, which causes tractional retinal detachment. In PVR, RPE cells are crucial contributors, and multiple signaling pathways, including the SMAD-dependent pathway, Rho pathway, MAPK pathways, Jagged/Notch pathway, and the Wnt/β-catenin pathway are activated. These pathways mediate the EMT of RPE cells, which play a key role in the pathogenesis of PVR. This review summarizes the current body of knowledge on the polarized phenotype of RPE, the role of cell-cell contact, and the molecular mechanisms underlying the RPE EMT in PVR, emphasizing key insights into potential approaches to prevent PVR.

Inflammation and cardiovascular diseases: lessons from seminal clinical trials

Inflammation has been long regarded as a key contributor to atherosclerosis. Inflammatory cells and soluble mediators play critical roles throughout arterial plaque development and accordingly, targeting inflammatory pathways effectively reduces atherosclerotic burden in animal models of cardiovascular (CV) diseases. Yet, clinical translation often led to inconclusive or even contradictory results. The Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) followed by the Colchicine Cardiovascular Outcomes Trial (COLCOT) were the first two randomized clinical trials to convincingly demonstrate the effectiveness of specific anti-inflammatory treatments in the field of CV prevention, while other phase III trials-including the Cardiovascular Inflammation Reduction Trial one using methotrexate-were futile. This manuscript reviews the main characteristics and findings of recent anti-inflammatory Phase III trials in cardiology and discusses their similarities and differences in order to get further insights into the contribution of specific inflammatory pathways on CV outcomes. CANTOS and COLCOT demonstrated efficacy of two anti-inflammatory drugs (canakinumab and colchicine, respectively) in the secondary prevention of major adverse CV events (MACE) thus providing the first confirmation of the involvement of a specific inflammatory pathway in human atherosclerotic CV disease (ASCVD). Also, they highlighted the NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome-related pathway as an effective therapeutic target to blunt ASCVD. In contrast, other trials interfering with a number of inflammasome-independent pathways failed to provide benefit. Lastly, all anti-inflammatory trials underscored the importance of balancing the risk of impaired host defence with an increase in infections and the prevention of MACE in CV patients with residual inflammatory risk.

MicroRNAs in the Vitreous Humor of Patients with Retinal Detachment and a Different Grading of Proliferative Vitreoretinopathy: A Pilot Study

Purpose

Although the expression of microRNAs (miRNAs) in retinal pigment epithelial (RPE) cells undergoing epithelial-mesenchymal transition (EMT) is involved in the pathogenesis of proliferative vitreoretinopathy (PVR), its expression in the vitreous of patients with primary retinal detachment (RD) and different PVR grading has not yet been investigated. We assessed the expression of miRNAs in the vitreous humor (VH) of patients diagnosed with RD and different grading of PVR.

Methods

The VH was extracted from the core of the vitreous chamber in patients who had undergone standard vitrectomy for primary RD. RNA was extracted and TaqMan Low-Density Arrays (TLDAs) were used for miRNA profiling that was performed by single TaqMan assays. A gene ontology (GO) analysis was performed on the differentially expressed miRNAs.

Results

A total of 15 eyes with RD, 3 eyes for each grade of PVR (A, B, C, and D) and 3 from unaffected individuals, were enrolled in this prospective comparative study. Twenty miRNAs were altered in the comparison among pathological groups. Interestingly, the expression of miR-143-3p, miR-224-5p, miR-361-5p, miR-452-5p, miR-486-3p, and miR-891a-5p increased with the worsening of PVR grading. We also identified 34 miRNAs showing differential expression in PVR compared to control vitreous samples. GO analysis showed that the deregulated miRNAs participate in processes previously associated with PVR pathogenesis.

Conclusions

The present pilot study suggested that dysregulated vitreal miRNAs may be considered as a biomarker of PVR and associated with the PVR-related complications in patients with RD.

Translational Relevance

The correlation between vitreal miRNAs and the pathological phenotypes are essential to identify the novel miRNA-based mechanisms underlying the PVR disease that would improve the diagnosis and treatment of the condition.

Repeated Injection of Methotrexate into Silicone Oil-Filled Eyes for Grade C Proliferative Vitreoretinopathy: A Pilot Study

PURPOSE

To evaluate the effects of repeated intra-silicone oil (SO) injections of methotrexate (MTX) on the outcomes of surgery for rhegmatogenous retinal detachment (RRD) with grade C proliferative vitreoretinopathy (PVR-C).

METHODS

In this prospective pilot case series, eyes with RRD and PVR-C underwent pars plana vitrectomy and intraocular injection of SO. At the conclusion of the procedure, 250 µg of MTX was injected into the SO-filled vitreous cavity. Intra-SO injection was repeated at weeks 3 and 6; the minimum follow-up period was 6 months. The main outcome measure was retinal reattachment rate.

RESULTS

Eleven eyes of 11 patients (mean age, 52.73 ± 18.01 years) were included. The mean follow-up period was 9 ± 3 months (range, 6-15 months). Total retinal detachment with anterior and/or posterior PVR-C was present in all eyes before surgery. Mean preoperative best-corrected visual acuity (BCVA) was 2.62 ± 0.04 logMAR. All operated eyes exhibited retinal reattachment posterior to the equator during the follow-up period. Mean postoperative BCVA was significantly improved to 1.02 ± 0.51 logMAR (p = 0.003). No ocular or systemic side effects were observed.

CONCLUSION

Repeated intra-SO injection of MTX as an adjunctive therapy for RRD complicated by PVR showed promising results and was not associated with adverse effects. Further studies are needed to confirm its possible beneficial effects on the final anatomic and functional outcomes in these cases.

Intra-silicone Oil Injection of Methotrexate in Retinal Reattachment Surgery for Proliferative Vitreoretinopathy

Purpose: To evaluate the role of intrasilicone oil injection of methotrexate (MTX) at the end of vitrectomy surgery for rhegmatogenous retinal detachment (RRD) associated with proliferative vitreoretinopathy (PVR).Methods: In this prospective comparative study, pars plana vitrectomy and retinal reattachment were performed for eyes with RRD with grade C PVR. In the MTX group, 250 µg MTX was injected into the silicone oil at the end of surgery. The rate of retinal redetachment associated with PVR was assessed.Results: In total, 44 eyes of 44 patients (22 in the MTX group and 22 controls) were included. Baseline characteristics were similar between the two groups. Retinal redetachment occurred in one eye (4.5%) in the MTX group and five eyes (22.7%) in the control group (p = 0.18). The change in visual acuity was similar between the two groups at final visit (p = 0.15).Conclusion: The rate of redetachment associated with PVR was lower after intrasilicone injection of MTX at the end of vitrectomy for RRD with severe PVR compared to control group; however, the difference was not statistically significant.

Comparative transcriptomic analysis reveals adriamycin-induced apoptosis via p53 signaling pathway in retinal pigment epithelial cells

OBJECTIVE

This paper applied a transcriptomic approach to investigate the mechanisms of adriamycin (ADR) in treating proliferative vitreoretinopathy (PVR) using ARPE-19 cells.

METHODS

The growth inhibitory effects of ADR on ARPE-19 cells were assessed by sulforhodamine B (SRB) assay and propidium iodide (PI) staining using flow cytometry. The differentially expressed genes between ADR-treated ARPE-19 cells and normal ARPE-19 cells and the signaling pathways involved were investigated by microarray analysis. Mitochondrial function was detected by JC-1 staining using flow cytometry and the Bcl-2/Bax protein family. The phosphorylated histone H2AX (γ-H2AX), phosphorylated checkpoint kinase 1 (p-CHK1), and phosphorylated checkpoint kinase 2 (p-CHK2) were assessed to detect DNA damage and repair.

RESULTS

ADR could significantly inhibit ARPE-19 cell proliferation and induce caspase-dependent apoptosis in vitro. In total, 4479 differentially expressed genes were found, and gene ontology items and the p53 signaling pathway were enriched. A protein-protein interaction analysis indicated that the TP53 protein molecules regulated by ADR were related to DNA damage and oxidative stress. ADR reduced mitochondrial membrane potential and the Bcl-2/Bax ratio. p53-knockdown restored the activation of c-caspase-3 activity induced by ADR by regulating Bax expression, and it inhibited ADR-induced ARPE-19 cell apoptosis. Finally, the levels of the γ-H2AX, p-CHK1, and p-CHK2 proteins were up-regulated after ADR exposure.

CONCLUSIONS

The mechanism of ARPE-19 cell death induced by ADR may be caspase-dependent apoptosis, and it may be regulated by the p53-dependent mitochondrial dysfunction, activating the p53 signaling pathway through DNA damage.

Proliferative Vitreoretinopathy: A Review

Proliferative vitreoretinopathy (PVR) is the most common cause for failure of rhegmatogenous retinal detachment repair and is characterized by the growth and contraction of cellular membranes within the vitreous cavity and on both sides of the retinal surface as well as intraretinal fibrosis. Currently, PVR is thought to be an abnormal wound healing response that is primarily driven by inflammatory, retinal, and RPE cells. At this time, surgery is the only management option for PVR as there is no proven pharmacologic agent for the treatment or prevention of PVR. Laboratory research to better understand PVR pathophysiology and clinical trials of various agents to prevent PVR formation are ongoing.