SMOKING IS A RISK FACTOR FOR PROLIFERATIVE VITREORETINOPATHY AFTER TRAUMATIC RETINAL DETACHMENT

Traumatic retinal detachment: A contemporary update

Retinal detachment following ocular trauma (TrRD) is one of the leading causes of blindness and visual impairment worldwide. In the absence of a standardized definition, the diagnosis of traumatic retinal detachment relies on identifying a history of trauma that precedes the detachment. There is an increasing pool of data regarding the etiology and epidemiology of TrRD.Various causes of TrRD mentioned in the literature include work-related eye trauma in construction and manufacturing industries, sports injuries, explosive eye injuries, road traffic accidents, and intraocular foreign bodies. Although there is extensive literature on post-trauma retinal detachments, a comprehensive discussion of its pathogenesis, management, outcomes, and complications is lacking. We offer an in-depth review of the epidemiology, risk factors, pathogenesis, diagnosis, management, and outcomes of TrRD based on the current literature.

Proliferative Vitreoretinopathy in Retinal Detachment: Perspectives on Building a Digital Twin Model Using Nintedanib

Proliferative vitreoretinopathy (PVR) is a pathological process characterized by the formation of fibrotic membranes that contract and lead to recurrent retinal detachment. Pars plana vitrectomy (PPV) is the primary treatment, but recurrence rates remain high, as surgery does not address the underlying molecular mechanisms driving fibrosis. Despite several proposed pharmacological interventions, no approved therapies exist, partly due to challenges in conducting preclinical and in vivo studies for ethical and safety reasons. This review explores the potential of computational models and Digital Twins, which are increasingly gaining attention in medicine. These tools could enable the development of progressively complex PVR models, from basic simulations to patient-specific Digital Twins. Nintedanib, a tyrosine kinase inhibitor targeting PDGFR, VEGFR, and FGFR, is presented as a prototype for computational models to simulate its effects on fibrotic pathways in virtual patient cohorts. Although still in its early stages, the integration of computational models and Digital Twins offers promising avenues for improving PVR management through more personalized therapeutic strategies.

The Wisconsin silicone oil study (report #1): anatomical and functional outcomes of repair of retinal detachment with proliferative vitreoretinopathy

BACKGROUND

Silicone oil (SO) is a long-term tamponade for repair of complex retinal pathology but has limitations including late redetachment. This study describes our experience with SO tamponade for repair of retinal detachment with proliferative vitreoretinopathy (PVR), with attention to anatomic and functional outcomes.

METHODS

Retrospective consecutive case series of eyes with retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR) receiving SO tamponade at the University of Wisconsin between 2013 and 2019. Group 1 defined as primary SO placement; Group 2 had SO placed after failing prior retinal detachment repair.

RESULTS

Inclusion criteria of SO placement for repair of RD with PVR was met for 117 eyes. The final reattachment rate was 84% for all eyes, with no difference between Groups 1 and 2. Vision improvement was 2.1 lines for Group 1 (p = 0.06 from baseline) and 4.6 lines for Group 2 (p < 0.0001). The mean number of silicone oil placements was 1.4. Less improvement in vision was noted with repeat SO placement, though overall functional vision of 5/200 or better was achieved in 63.2% of patients.

CONCLUSIONS

SO tamponade allows long-term anatomical stabilisation and substantial vision recovery in eyes with retinal detachment complicated by PVR. Rates of anatomic and functional success have improved significantly when compared to prior studies using oil tamponade for repair of PVR.

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.

Retinal detachment

Retinal detachment (RD) occurs when the neurosensory retina, the neurovascular tissue responsible for phototransduction, is separated from the underlying retinal pigment epithelium (RPE). Given the importance of the RPE for optimal retinal function, RD invariably leads to decreased vision. There are three main types of RD: rhegmatogenous, tractional and exudative (also termed serous) RD. In rhegmatogenous RD, one or more retinal breaks enable vitreous fluid to enter the subretinal space and separate the neurosensory retina from the RPE. In tractional RD, preretinal, intraretinal or subretinal membranes contract and exert tangential forces and elevate the retina from the underlying RPE. Finally, in exudative RD, an underlying inflammatory condition, vascular abnormality or the presence of a tumour causes exudative fluid to accumulate in the subretinal space, exceeding the osmotic pump function of the RPE. The surgical management of RD usually involves pars plana vitrectomy, scleral buckling or pneumatic retinopexy. The approach taken often depends on patient characteristics as well as on practitioner experience and clinical judgement. Advances in surgical technology and continued innovation have improved outcomes for many patients. However, even if retinal re-attachment is achieved, some patients still experience decreased vision or other visual symptoms, such as metamorphopsia, that diminish their quality of life. Continued research in the areas of neuroprotection and retinal biology as well as continued surgical innovation are necessary to enhance therapeutic options and outcomes for these patients.

Risk factors for proliferative vitreoretinopathy after retinal detachment surgery: A systematic review and meta-analysis

BACKGROUND

To comprehensively investigate risk factors for proliferative vitreoretinopathy (PVR) after retinal detachment (RD) surgery.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were systematically searched until May 22, 2023. Risk factors included demographic and disease-related risk factors. Odds ratios (ORs) and weighted mean differences (WMDs) were used as the effect sizes, and shown with 95% confidence intervals (CIs). Sensitivity analysis was conducted. The protocol was registered with PROSPERO (CRD42022378652).

RESULTS

Twenty-two studies of 13,875 subjects were included in this systematic review and meta-analysis. Increased age was associated with a higher risk of postoperative PVR (pooled WMD = 3.98, 95%CI: 0.21, 7.75, P = 0.038). Smokers had a higher risk of postoperative PVR than non-smokers (pooled OR = 5.07, 95%CI: 2.21-11.61, P<0.001). Presence of preoperative PVR was associated with a greater risk of postoperative PVR (pooled OR = 22.28, 95%CI: 2.54, 195.31, P = 0.005). Presence of vitreous hemorrhage was associated with a greater risk of postoperative PVR (pooled OR = 4.12, 95%CI: 1.62, 10.50, P = 0.003). Individuals with aphakia or pseudophakia had an increased risk of postoperative PVR in contrast to those without (pooled OR = 1.41, 95%CI: 1.02, 1.95, P = 0.040). The risk of postoperative PVR was higher among patients with macula off versus those with macula on (pooled OR = 1.85, 95%CI: 1.24, 2.74, P = 0.002). Extent of RD in patients with postoperative PVR was larger than that in patients without (pooled WMD = 0.31, 95%CI: 0.02, 0.59, P = 0.036). Patients with postoperative PVR had longer duration of RD symptoms than those without (pooled WMD = 10.36, 95%CI: 2.29, 18.43, P = 0.012).

CONCLUSION

Age, smoking, preoperative PVR, vitreous hemorrhage, aphakia or pseudophakia, macula off, extent of RD, and duration of RD symptoms were risk factors for postoperative PVR in patients undergoing RD surgery, which may help better identify high-risk patients, and provide timely interventions.

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.

TNF-α and NF-κB signaling play a critical role in cigarette smoke-induced epithelial-mesenchymal transition of retinal pigment epithelial cells in proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) is characterized by the growth and contraction of cellular membranes within the vitreous cavity and on both surfaces of the retina, resulting in recurrent retinal detachments and poor visual outcomes. Proinflammatory cytokines like tumor necrosis factor alpha (TNFα) have been associated with PVR and the epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells. Cigarette smoke is the only known modifiable risk factor for PVR, but the mechanisms are unclear. The purpose of this study was to examine the impact of cigarette smoke on the proinflammatory TNFα/NF-κB/Snail pathway in RPE cells to better understand the mechanisms through which cigarette smoke increases the risk of PVR. Human ARPE-19 cells were exposed to cigarette smoke extract (CSE), for 4 to 24-hours and TNFα, Snail, IL-6, IL-8, and α-SMA levels were analyzed by qPCR and/or Western blot. The severity of PVR formation was assessed in a murine model of PVR after intravitreal injection of ARPE-19 cells pre-treated with CSE or not. Fundus imaging, OCT imaging, and histologic analysis 4 weeks after injection were used to examine PVR severity. ARPE-19 cells exposed to CSE expressed higher levels of TNFα, SNAIL, IL6 and IL8 mRNA as well as SNAIL, Vimentin and α-SMA protein. Inhibition of TNFα and NF-κB pathways blocked the effect of CSE. In vivo, intravitreal injection of ARPE-19 cells treated with CSE resulted in more severe PVR compared to mice injected with untreated RPE cells. These studies suggest that the TNFα pathway is involved in the mechanism whereby cigarette smoke increases PVR. Further investigation into the role of TNFα/NF-κB/Snail in driving PVR and pharmacological targeting of these pathways in disease are warranted.

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.

More than Meets the Eye: The Aryl Hydrocarbon Receptor is an Environmental Sensor, Physiological Regulator and a Therapeutic Target in Ocular Disease

The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor originally identified as an environmental sensor of xenobiotic chemicals. However, studies have revealed that the AHR regulates crucial aspects of cell growth and metabolism, development and the immune system. The importance of the AHR and AHR signaling in eye development, toxicology and disease is now being uncovered. The AHR is expressed in many ocular tissues including the retina, choroid, cornea and the orbit. A significant role for the AHR in age-related macular degeneration (AMD), autoimmune uveitis, and other ocular diseases has been identified. Ligands for the AHR are structurally diverse organic molecules from exogenous and endogenous sources. Natural AHR ligands include metabolites of tryptophan and byproducts of the microbiome. Xenobiotic AHR ligands include persistent environmental pollutants such as dioxins, benzo (a) pyrene [B (a) P] and polychlorinated biphenyls (PCBs). Pharmaceutical agents including the proton pump inhibitors, esomeprazole and lansoprazole, and the immunosuppressive drug, leflunomide, activate the AHR. In this review, we highlight the role of the AHR in the eye and discuss how AHR signaling is involved in responding to endogenous and environmental stimuli. We also present the emerging concept that the AHR is a promising therapeutic target for eye disease.

Managing PVR in the Era of Small Gauge Surgery

Proliferative vitreoretinopathy (PVR) is the leading cause of failed rhegmatogenous retinal detachment (RRD) surgery. Based upon the presence of clinical features and due to associated underlying risk factors, it is classified into various grades based upon its severity and extent of involvement. Despite excellent skills, flawless techniques, and high-end technology applied in the management of RRD, PVR still occurs in 5–10% of cases. Due to the advancements in wide angle viewing systems, advance vitrectomy machines and fluidics, early identification, use of long-term heavy silicon oil tamponades, high-speed cutters, small-gauge vitrectomies, use of perfluorocarbon liquid (PFCL), and small-gauge forceps and scissors, the success rate in the management of PVR has increased leading to improved anatomical outcomes. However, functional outcomes do not correlate well with improved anatomical outcomes. Various complications occur after RRD repair that are responsible for re-retinal detachment and recurrence of PVR. This article highlights causes, risk factors, classification, grading, diagnosis, and approach to management of PVR and post-PVR surgery complications.

SURGICAL FAILURES AFTER PRIMARY SCLERAL BUCKLING FOR RHEGMATOGENOUS RETINAL DETACHMENT: Comparison of Eyes With and Without Proliferative Vitreoretinopathy

PURPOSE

To compare proliferative vitreoretinopathy (PVR)-related surgical failure and non-PVR-associated failure after scleral buckling for primary rhegmatogenous retinal detachment.

METHODS

In this single-center, retrospective, consecutive case series, eyes with surgical failure after scleral buckling for primary rhegmatogenous retinal detachment were identified. Eyes with surgical failure were categorized as PVR-associated and non-PVR-associated failure, and these groups were compared.

RESULTS

Of the 530 scleral buckling procedures performed, 69 were surgical failures (13%), of which 27 of the 530 (5%) were due to PVR and 42 of the 530 (8%) were from non-PVR causes. Patients with PVR-associated failure were more likely to be smokers (P < 0.001), have a delayed presentation after symptoms (P = 0.011), have preoperative vitreous hemorrhage (P = 0.004), and have preoperative PVR (P = 0.002). Multivariate logistic regression models showed that the odds of PVR-associated failure were greater in eyes with preoperative vitreous hemorrhage (odds ratio, 8.2; P = 0.048), preoperative PVR (odds ratio, 22.7; P = 0.023), and among previous smokers (odds ratio, 28.8; P < 0.001). Thirty-two of 69 patients (46%) required one additional surgical intervention, and 37 of the 69 patients (53%) required two or more additional interventions to achieve final reattachment.

CONCLUSION

Proliferative vitreoretinopathy-related surgical failure after primary scleral buckling was 5%. Risk factors for PVR-associated failure parallel those commonly referenced for pars plan vitrectomy, including smoking history, preoperative vitreous hemorrhage, and preoperative PVR.

Clinical Outcomes of Rhegmatogenous Retinal Detachment Treated With Pneumatic Retinopexy

IMPORTANCE

Pneumatic retinopexy (PR) is the only clinic-based method of rhegmatogenous retinal detachment (RRD) repair. Registry-acquired clinical practice setting outcomes data with this procedure have not yet been reported.

OBJECTIVE

To describe the clinical outcomes associated with RRD treated primarily with PR.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective cohort study, data from patients 19 years and older with noncomplex RRD treated at academic and private ophthalmology practices participating in the American Academy of Ophthalmology IRIS Registry (Intelligent Research in Sight) were analyzed. Data were collected from January 1, 2013, to December 31, 2019, and data were analyzed from January to December 2020.

EXPOSURES

Data from the IRIS Registry were queried for eyes that underwent PR for noncomplex RRD and had at least 3 months of follow-up. Cases were identified by a combination of diagnosis code for RRD and a Current Procedural Terminology code for PR.

MAIN OUTCOMES AND MEASURES

The number of eyes that achieved single-operation success (SOS), defined as retinal reattachment without a subsequent retinal detachment surgery or repeated PR.

RESULTS

Of 9553 included patients, 5827 (61.0%) were male, and the mean (SD) age was 62 (10) years. A total of 9659 eyes were identified. SOS was achieved in 6613 eyes (68.5%). Best-corrected visual acuity significantly differed 9 to 12 months after treatment between the SOS group, with a mean of 0.24 logMAR (95% CI, 0.23-0.25; approximate Snellen equivalent, 20/35), and the single-operation failure group, with a mean of 0.43 logMAR (95% CI, 0.40-0.46; approximate Snellen equivalent, 20/54). Among all patients, the mean time to maximal visual recovery was 268 days (95% CI, 260-276). Endophthalmitis was observed in 3 eyes (0.03%). SOS was associated with female sex (odds ratio, 1.51; 95% CI, 1.38-1.65), while current smoking status was associated single-operation failure (odds ratio, 0.78; 95% CI, 0.68-0.91).

CONCLUSIONS AND RELEVANCE

In this registry-based study, which encompasses a large number of eyes drawn from multiple, heterogenous electronic health record systems, SOS was achieved in 68.5% of eyes with noncomplex RRD treated by primary PR. It is unknown how these outcomes would have compared with other methods of RRD repair in this cohort.

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.

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.

PREDICTIVE FACTORS FOR PROLIFERATIVE VITREORETINOPATHY FORMATION AFTER UNCOMPLICATED PRIMARY RETINAL DETACHMENT REPAIR

PURPOSE

To determine predictive factors of proliferative vitreoretinopathy (PVR) formation after uncomplicated primary retinal detachment repair.

METHODS

Retrospective, single-center, case-control study of 74 consecutive patients with (37 eyes) and without (37 eyes) PVR formation after undergoing uncomplicated primary surgery for retinal detachment repair. Logistic regression was used to assess factors associated with PVR formation.

RESULTS

Retinal detachment involving the macula was 4.2 times (adjusted odds ratio; 95% confidence interval, 1.4-12.9; P = 0.0119) more likely to have PVR formation compared with those without. Patients who were current or former smokers were 3.6 times (adjusted odds ratio; 95% confidence interval, 1.1-11.7; P = 0.0352) more likely to have PVR formation compared with nonsmokers. Compared with 25-gauge (g) vitrectomy, larger gauge vitrectomy (20 g or 23 g) was 3.6 times (adjusted odds ratio; 95% confidence interval, 1.2-11.3; P = 0.0276) more likely to have PVR formation. Duration of retinal detachment symptoms, high myopia, lens status, lattice degeneration, location of retinal break, number of retinal breaks, and surgical technique (e.g., scleral buckle with or without vitrectomy versus vitrectomy alone) were not found to be predictive of PVR formation.

CONCLUSION

Cigarette smoking and macular involvement are significant risk factors predictive of PVR formation after uncomplicated primary retinal detachment repair.

Thomas A. Swift's Electric Rifle Injuries to the Eye and Ocular Adnexa: The Management of Complex Trauma

PURPOSE

To report the ocular and adnexal injuries sustained by patients with Thomas A. Swift's electric rifles (TASER; TASER International, Scottsdale, AZ), review the literature, and discuss the management of this complex trauma.

DESIGN

Multicenter, retrospective case series and literature review.

PARTICIPANTS

Seventeen eyes of 16 patients (5 eyes of 5 patients treated at 3 institutions, and 12 eyes of 11 previously reported cases).

METHODS

The clinical data of 17 eyes were pooled. Spearman's correlation coefficient was used to assess the association between the extent of TASER injury and patient outcomes.

MAIN OUTCOME MEASURES

Extent of TASER injury (zone of injury, penetrating vs. perforating) and association with patient outcomes (visual acuity [VA] and retinal detachment [RD]).

RESULTS

In our cohort, 4 patients were transported by law enforcement and 1 was transferred from a community hospital. Four patients were taken to the operating room for TASER removal and globe repair; 1 patient underwent removal in the emergency room. Of 17 pooled cases, 12 (71%) involved open-globe injury. Of these, there was a high rate of zone 3 injuries (100%; n = 12) and a high incidence of RD (73%; 8 of 11, eviscerated eye excluded). Among patients with closed-globe injury (n = 5), 1 patient demonstrated exudative RD and 1 patient demonstrated retinal dialysis with RD. Of 10 patients with RD, 1 (10%) achieved resolution with monitoring (exudative RD); 1 (10%) underwent cryopexy and pneumatic retinopexy; 3 (30%) underwent vitrectomy, and 5 (50%) with poor prognosis did not undergo vitreoretinal surgery. In the 3 patients who underwent vitrectomy, all 3 (100%) demonstrated redetachment resulting from proliferative vitreoretinopathy and required additional surgery. Visual acuity on presentation was significantly correlated with final VA (ρ = 0.783; P = 0.02). Men (94%) were more likely than women (6%) to sustain TASER trauma. Median age was 26 years. There was a 50% rate of loss to follow-up.

CONCLUSIONS

Thomas A. Swift's electric rifle injuries to the eyes or ocular adnexa represent complex trauma. Zone 3 injuries are common. The visual prognosis is guarded, and eyes may require multiple surgeries to preserve vision. Patients are at high risk for loss to follow-up by way of incarceration.

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.

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

Purpose

The purpose of this study was to develop a method for isolating, culturing, and characterizing cells from patient-derived membranes in proliferative vitreoretinopathy (PVR) to be used for drug testing.

Methods

PVR membranes were obtained from six patients with grade C PVR. Membrane fragments were analyzed by gross evaluation, fixed for immunohistologic studies to establish cell identity, or digested with collagenase II to obtain single cell suspensions for culture. PVR-derived primary cultures were used to examine the effects of methotrexate (MTX) on proliferation, migration, and cell death.

Results

Gross analysis of PVR membranes showed presence of pigmented cells, indicative of retinal pigment epithelial cells. Immunohistochemistry identified cells expressing α-smooth muscle actin, glial fibrillary acidic protein, Bestrophin-1, and F4/80, suggesting the presence of multiple cell types in PVR. Robust PVR primary cultures (C-PVR) were successfully obtained from human membranes, and these cells retained the expression of cell identity markers in culture. C-PVR cultures formed membranes and band-like structures in culture reminiscent of the human condition. MTX significantly reduced the proliferation and band formation of C-PVR, whereas it had no significant effect on cell migration. MTX also induced regulated cell death within C-PVR as assessed by increased expression of caspase-3/7.

Conclusions

PVR cells obtained from human membranes can be successfully isolated, cultured, and profiled in vitro. Using these primary cultures, we identified MTX as capable of significantly reducing growth and inducing cell death of PVR cells in vitro.