Adjuvant 5-fluorouracil and heparin prevents proliferative vitreoretinopathy : Results from a randomized, double-blind, controlled clinical trial

Assessing the therapeutic potential of astaxanthin in experimental proliferative vitreoretinopathy models

PurposeThis study evaluates the effectiveness of astaxanthin in treating experimental proliferative vitreoretinopathy (PVR) in rats.MethodsFifty-six Sprague Dawley rats were divided into 4 groups. PVR was induced using dispase and astaxanthin was administered intravitreally at concentrations of 10 ng/μL and 100 ng/μL. The effects on TGF-ß, VEGF, PDGF, FGF2 and IL-1ß were measured by ELISA and retinal changes were analysed histopathologically and immunohistochemically.ResultsAstaxanthin at 10 ng/μL and 100 ng/μL administered to the treatment groups significantly decreased TGF-β, VEGF, FGF2, IL-1, and PDGF levels compared to the sham group (p < 0.05). At the 100 ng/μL dose, more significant decreases were observed, especially in PDGF and IL-1 levels (p < 0.01). Histopathologic scoring revealed that the treated groups had significantly lower PVR scores than the Sham group, with the highest dose showing the greatest improvement (p < 0.01). Furthermore, treated groups exhibited improved retinal architecture and reduced fibrotic tissue formation. Immunohistochemical staining for VEGF was positive in all groups except Control, with no significant differences in VEGF expression intensity between groups.ConclusionAstaxanthin effectively reduces both biochemical and histopathological markers of PVR, highlighting its potential as a novel therapeutic agent for managing this challenging condition in clinical practice.

Vitreous proteomics in rhegmatogenous retinal detachment and proliferative vitreoretinopathy

Rhegmatogenous retinal detachment (RRD) is a serious ophthalmic condition that, if untreated, can result in significant vision loss. Proliferative vitreoretinopathy (PVR) often complicates RRD and is the leading cause of surgical failure. Proteomic analysis of the vitreous has emerged as a powerful tool for elucidating the molecular mechanisms underlying RRD and PVR. This article reviews proteomic findings related to these conditions. A comprehensive literature search on PubMed was conducted, focusing on studies of vitreous proteomics in RRD and PVR published between 1988 and August 2024. Relevant findings on protein expression, metabolic pathways, and therapeutic targets were synthesized. Proteomic studies reveal significant alterations in photoreceptor-specific proteins, such as rhodopsin and Monocyte Chemoattractant Protein-1 (MCP-1), associated with apoptosis and inflammation during RRD. Metabolic dysregulation is evidenced by changes in glycolytic enzymes and antioxidants, including downregulation of peroxiredoxin-2 and ascorbic acid, suggesting impaired energy production and oxidative stress. Elevated cytokines, complement proteins, and matrix metalloproteinases highlight the role of inflammation and extracellular matrix remodelling in disease progression. Cytokine expression in PVR demonstrates distinct temporal patterns, with early stages marked by T-cell activation and mTOR pathway-related cytokines, and advanced stages characterized by monocyte chemoattractants associated with chronic inflammation. Currently, the potential of pharmacologic interventions in RRD and PVR remains limited. In contrast, proteomics offers critical insights into molecular mechanisms, identifying potential biomarkers and therapeutic pathways. The adoption of single-molecule and top-down proteomics, along with the integration of advanced technologies with artificial intelligence and bioinformatics, holds promise for accelerating progress toward precision medicine. These developments represent a promising avenue for future research and clinical application.

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.

A pilot study of intraoperative melphalan to prevent recurrent PVR: the IOMPVR study

BACKGROUND

Proliferative vitreoretinopathy (PVR) is a major cause of failure in cases of retinal detachment (RD) repair. Intravitreal melphalan, a known inhibitor of cellular proliferation, offers a novel therapeutic approach to reduce PVR recurrence and improve outcomes. We evaluated the safety and efficacy of 5 µg/0.1 ml intravitreal melphalan at the end of pars plana vitrectomy (PPV) before silicone oil (SO) injection in eyes with primary PVR related to rhegmatogenous retinal detachments (RRDs) with a minimal 90-day follow-up period.

METHODS

This prospective, cross-sectional, interventional pilot study was conducted at the Department of Ophthalmology of the Federal University of São Paulo in patients with primary RRD and PVR. Patients were included who were aged 18 to 85 years with PVR grade CP2 or worse secondary to RRDs in eyes without having undergone a previous RRD surgery. They underwent PPV + scleral buckle + fluid air exchange followed by intravitreal injection of 5 µg/0.1 ml melphalan (270 mOsm) and SO injection.

RESULTS

Six eyes of six patients were enrolled. Ocular examination and imaging showed no retinal toxicity. The logarithm of the minimum angle of resolution best-corrected visual acuity improved from the mean ± standard deviation preoperatively of 2.11 ± 0.22 to 0.89 ± 0.37 at 30 and to 0.84 ± 0.42 at 90 days postoperative (P < 0.001). Optical coherence tomography identified intraretinal cysts in five of six eyes and outer retinal layer loss in all study eyes. Only one of six eyes developed a recurrent localized RD on day 90 unrelated to recurrent PVR. PVR recurrence was not observed during the study follow-up.

CONCLUSIONS

In this pilot study, the preliminary data showed that PPV followed by intravitreal injection of 5 µg/0.1 ml melphalan was not related to ocular toxicity. The absence of PVR recurrence at 3 months follow-up in these complex PVR eyes is an interesting finding that justifies further investigation.

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.

Economic evaluation of an adjunctive intraocular and peri-ocular steroid vitreoretinal surgery for open globe trauma: Cost-effectiveness of the ASCOT randomised controlled trial

BACKGROUND

In the United Kingdom, it is estimated that 5,000 patients sustain eye injuries or ocular trauma requiring hospital admission annually, of which 250 patients will be permanently blinded. This study explores the cost-effectiveness of Adjunctive Steroid Combination in Ocular Trauma (ASCOT) given during surgery versus standard treatment in vitreoretinal surgery in patients with open globe trauma.

METHODS

This economic evaluation was embedded alongside the ASCOT RCT (ClinicalTrials.gov Identifier: NCT02873026). We conducted a primary cost-effectiveness analysis from a National Health Service perspective using the proportion of patients who achieved a visual acuity of 10 or more letter improvement on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale as the measure of effect, in developing incremental cost-effectiveness ratios (ICERs). Secondary cost-utility analysis using the EuroQol 5 Dimension 5 Level (EQ-5D-5L) to generate a cost per quality-adjusted life-year (QALY), and a cost-effectiveness analysis using vision-specific quality of life (QoL) was conducted. Sensitivity analyses were also applied to investigate parameter uncertainties.

RESULTS

The sample size of the ASCOT intervention arm and standard care arm of this study was 130 and 129, respectively. The intervention cost per patient was estimated at £132. The proportion of participants with an ETDRS of 10 or more letter improvement was 0.47 for the ASCOT group with a mean cost of £5,526 per patient, while the standard care group had an effect of 0.43 with a mean cost of £5,099 per patient. The ICER value of the primary outcome was £12,178 per 10 or more letter improvement on the ETDRS score. The secondary result in terms of cost per QALYs gained had a probability of 44% being cost-effective at a willingness-to-pay threshold of £30,000/QALY gained.

CONCLUSIONS

Though there is no formally accepted cost-effectiveness willingness-to-pay threshold for 10-letter or more improvement, the ASCOT intervention for open globe trauma is a low-cost intervention. The ASCOT intervention is not cost-effective when compared to the standard care in this group and setting. The proportion of patients in the ASCOT intervention arm with 10 or more letter improvement produced some positive results but this is outweighed by the costs.

Intravitreal Infliximab for the Treatment of Proliferative Vitreoretinopathy (FIXER): A Randomized Controlled Phase II Trial

OBJECTIVE

To study the safety and efficacy of intravitreal infliximab administered at the conclusion of pars plana vitrectomy (PPV) in the treatment of proliferative vitreoretinopathy (PVR) associated with rhegmatogenous retinal detachment (RRD).

DESIGN

Randomized controlled phase II clinical trial.

SUBJECTS

Patients with primary RRD and grade C PVR, according to the updated Retina Society Classification.

METHODS

Sixty-six patients were randomized in a 1:1 ratio to undergo PPV and silicone oil (SO) injection with or without intravitreal injection of 1 mg/0.05 mL of infliximab in the air-filled globe before SO injection at PPV conclusion. Surgeons were masked to treatment allocation until PPV conclusion.

MAIN OUTCOME MEASURES

The primary outcome measure was anatomic success (defined as complete retinal reattachment without a tamponade at 6 months post SO removal). Secondary outcome measures were final best-corrected visual acuity (BCVA), single-operation success rate (SOSR), rate of recurrent detachment, central macular thickness (CMT) by macular OCT, macular function by multifocal electroretinogram, and macular vascular density (VD) by OCT angiography.

RESULTS

Sixty eyes of 60 patients, 30 eyes in each group, completed the study. At baseline, there were no differences regarding age, gender, history of trauma, lens status, duration of RRD, BCVA, intraocular pressure (IOP), intraocular inflammation (IOI), detachment extent in clock hours, number/size of breaks, presence of vitreous hemorrhage, axial length, or grade/extent of PVR between both groups. For the outcome measures, 30 eyes in the infliximab group achieved anatomic success vs. 29 eyes in the control group. The SOSR was higher in the infliximab group (26) vs. the control (23), but this was not statistically significant (P = 0.317). Final logarithm of the minimum angle of resolution BCVA was better in the infliximab group (mean, 0.96; standard deviation [SD], 0.4; Snellen equivalent ≈ 20/180) vs. the control (mean, 1.14; SD, 0.4); Snellen equivalent ≈ 20/280; P = 0.044). There were no differences regarding IOP, IOI, time of SO removal, macular function, CMT, or VD.

CONCLUSIONS

Pars plana vitrectomy with SO tamponade with or without intravitreal infliximab is effective in treating PVR-associated RRD. Infliximab may be associated with modest improvement in final visual outcomes but not anatomic outcomes.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Nano-Based Drug Approaches to Proliferative Vitreoretinopathy Instead of Standard Vitreoretinal Surgery

Proliferative vitreoretinopathy (PVR) has traditionally been managed with vitreoretinal surgery. Although there have been several recent innovations in this surgery to make the retinal approach as uninvasive as possible, the outcomes remain unsatisfactory. Significant complications remain and the complexity of the surgical approach is challenging. The focus of this review was to investigate and discuss the effectiveness of nanomedicine, featuring a wide range of drugs and molecules, as a novel potential treatment for PVR. To date, ocular drug delivery remains a significant issue due to the physiological and anatomical barriers, dynamic or static, which prevent the entry of exogenous molecules. We tried to summarize the nanotechnology-based ophthalmic drugs and new nanoparticles currently under research, with the intention of tackling the onset and development of PVR. The purpose of this review was to thoroughly and analytically examine and assess the potential of nano-based techniques as innovative strategies to treat proliferative vitreoretinopathy (PVR). This study aimed to emphasize the breakthroughs in nanomedicine that provide promising therapeutic options to enhance the results of vitreoretinal surgery and halt disease progression, considering the complexity and difficulty of PVR treatment. The future directions of the nanoparticles and nanotherapies applied to PVR highlight the importance of investing in the development of better designs and novel ophthalmic formulations in order to accomplish a mini-invasive ocular approach, replacing the standard-of-care vitreoretinal surgery.

Clinical therapeutics for proliferative vitreoretinopathy in retinal detachment

Proliferative vitreoretinopathy (PVR) is an abnormal and prolonged healing response to retinal injury (retinal detachment, post retinal detachment surgery) characterised by: pre/subretinal membrane formation; retinal gliosis and retinal shortening, retinal pigment epithelium cell proliferation; and increased glial (mainly Mu¨ller cells), fibroblast and inflammatory cell (macrophage, lymphocyte) activity, leading to tractional retinal holes/breaks and multiple costly eye operations suffered by patients. PVR can cause retinal re-detachment following primary surgical intervention for rhegmatogenous retinal detachment. Vitrectomy and scleral buckling surgery are the main approaches for treating PVR complications of retinal detachment. Patients require many operations to remove the scar tissue but vision results are suboptimal, and do not meet patient expectations. Over the past 40 years, this has been one of the greatest challenges for vitreoretinal surgeons and patients. Despite previous large clinical trials of multiple candidate drug therapeutics, no proven adjunctive treatment currently exists to either prevent, reduce, or treat PVR formation in retinal detachment. Both cellular proliferation and the intraocular inflammatory response are realistic targets for adjunctive treatments in PVR. The cellular components of PVR periretinal membranes (retinal pigment epithelial, glial, inflammatory and fibroblastic cells) proliferate and are thus targets for antiproliferative agents. In recent years, several new therapeutics have been tested, and we present an updated review of the clinical therapeutics for PVR in retinal detachment.

Vitreoretinal Surgery in Uveitis: From Old to New Concepts - A Review

PURPOSE

The aim of this article is to do a comprehensive literature review about the current role of pars plana vitrectomy in uveitis and in its different structural complications such as cystoid macular edema, epiretinal membrane, macular hole, and retinal detachment.

METHODS

This comprehensive literature review was performed based on a search on PubMed, BioMed Central, Science Open, and CORE databases, of relevant articles abording pars plana vitrectomy in uveitis.

DISCUSSION

Uveitis is a complex disease with multiple etiologies and pathogenic mechanisms. Therapeutic pars plana vitrectomy (PPV) may aid in uveitic structural complications such as cystoid macular edema, epiretinal membranes, macular hole, and retinal detachments even though some cases may present unpredictable visual outcomes. Diagnostic PPV with appropriate ancillary testing is also a valuable tool for the assessment and diagnosis of uveitis in a large proportion of patients.

CONCLUSION

Over the years, pars plana vitrectomy has undergone significant transformations since its invention nearly 5 decades ago, however, the quality of evidence in the literature regarding its use for uveitis has not improved in the same way. Even though some structural uveitis complications (as previously mentioned) may respond well to surgery, there is still a certain unpredictability regarding its visual outcomes. On the other hand, diagnostic vitrectomy with appropriate ancillary testing is also a valuable tool for the assessment and diagnosis of uveitis in a large proportion of patients.

Advancements in Therapeutic Approaches for Proliferative Vitreoretinopathy: A Comprehensive Review

Proliferative vitreoretinopathy (PVR) is a significant complication of retinal detachment surgery, characterized by the growth of fibrous membranes that can lead to recurrent retinal detachment and vision loss. This comprehensive review aims to summarize the latest advancements in the therapeutic approaches for PVR, encompassing historical perspectives, current surgical techniques, pharmacological interventions, biological and genetic therapies, and novel experimental treatments. Traditional surgical methods, such as vitrectomy, have been refined with advanced instrumentation and techniques to improve outcomes. Pharmacological treatments, including anti-inflammatory and anti-proliferative agents, are being explored to prevent and manage PVR. Emerging therapies, such as stem cell and gene therapy, offer promising new avenues for treatment. Despite these advancements, challenges remain in preventing recurrence and improving long-term outcomes. This review highlights the progress made and identifies areas for future research, emphasizing the importance of continued innovation to enhance patient care and reduce the burden 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.

Efficacy of 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) in high-risk pediatric retinal detachment; randomized clinical trial

BACKGROUND

Pediatric rhegmatogenous retinal detachments (PRRDs) are complex, rare occurrences and are often related to trauma or congenital abnormalities. Children often do not recognize or report symptoms of retinal detachment. Thus at presentation, PRRD is typically advanced often with macular involvement, proliferative vitreoretinopathy (PVR), chronic duration, and poor visual acuity. Because 5-FU and LMWH are effective in different aspects in the PVR process, it was believed that a syngergistic approach to the prevention of PVR would be advantageous.

METHODS

After informed consent, children under 14 years of age with high-risk PRRD underwent pars plana vitrectomy and silicone oil injection with scleral buckle divided into 2 groups in prospective randomized trial. Group A received intraoperative infusion of 5-FU (200 µg/ml) and LMWH (5 IU/ml), group B received infusion of normal saline. Primary outcome was occurrence of recurrent PRRD within 12 weeks, secondary outcomes were occurrence of PVR, best corrected visual acuity (BCVA), number and timing of secondary procedures within 12 weeks.

RESULTS

The study included 42 eyes of 41 patients, 21 in group A and 21 in group B, the duration of PRRD ranged from 0.5 to 7 months in group A and 0.25-5 months in group B.The rate of recurrent PRRD was higher in group B 33% compared to 19% in group A (p = 0.292). The mean timing of occurrence of recurrent PRRD was 9.5 ± 5 weeks in group A compared to 2.86 ± 2.41 weeks in group B (p = 0.042), more patients in group B ended up with more advanced PVR (p = 0.038), BCVA was hand movement (HM) only in all cases preoperatively and improved to HM-0.3 Snellen in group A compared to light perception (PL)-0.1Snellen in group B (p = 0.035), there was no difference in any of secondary procedures but with later timing in group A 9.71 ± 3.73 weeks than in group B 4.0 ± 2.83 weeks (p = 0.042).

CONCLUSION

This study concluded that the use of the 5-FU and LMWH combination in high risk PRRD resulted in lower rate of postoperative PVR, later recurrence of PRRD and better final BCVA.

TRIAL REGISTRATION NUMBER

Registry: clinicaltrials.gov PRS NCT06166914 date of initial release 4/12/2023. Unique Protocol ID: 9,163,209 date 21/10/2021. Retrospectively registered.

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.

Randomised controlled trial of adjunctive triamcinolone acetonide in eyes undergoing vitreoretinal surgery following open globe trauma: The ASCOT study

BACKGROUND/AIMS

To investigate the clinical effectiveness of adjunctive triamcinolone acetonide (TA) given at the time of vitreoretinal surgery following open globe trauma (OGT).

METHODS

A phase 3, multicentre, double-masked randomised controlled trial of patients undergoing vitrectomy following OGT comparing adjunctive TA (intravitreal and subtenons) against standard care (2014-2020). The primary outcome was the proportion of patients with at least 10 Early Treatment Diabetic Retinopathy Study (ETDRS) letter improvement in corrected visual acuity (VA) at 6 months. Secondary outcomes included: change in ETDRS, retinal detachment (RD) secondary to PVR, retinal reattachment, macular reattachment, tractional RD, number of operations, hypotony, elevated intraocular pressure and quality of life.

RESULTS

280 patients were randomised over 75 months, of which 259 completed the study. 46.9% (n=61/130) of patients in the treatment group had a 10-letter improvement in VA compared with 43.4% (n=56/129) of the control group (difference 3.5% (95% CI -8.6% to 15.6%), OR=1.03 (95% CI 0.61 to 1.75), p=0.908)). Secondary outcome measures also failed to show any treatment benefit. For two of the secondary outcome measures, stable complete retinal and macular reattachment, outcomes were worse in the treatment group compared with controls, respectively, 51.6% (n=65/126) vs 64.2% (n=79/123), OR=0.59 (95% CI 0.36 to 0.99), and 54.0% (n=68/126) vs 66.7% (n=82/123), OR=0.59 (95% CI 0.35 to 0.98), for TA vs control.

CONCLUSION

The use of combined intraocular and sub-Tenons capsule TA is not recommended as an adjunct to vitrectomy surgery following OGT.

TRIAL REGISTRATION NUMBER

NCT02873026.

Evaluation of a steroid delivery system to mitigate the severity of proliferative vitreoretinopathy in a minipig model

Purpose

To investigate the efficacy of liposomal prednisolone phosphate to mitigate the severity of proliferative vitreoretinopathy (PVR) in a minipig model of PVR.

Methods

A total of 18 eyes of 9 minipigs underwent PVR induction surgically. Eyes were randomized equally into three groups: intravitreal injection of liposomal prednisolone phosphate (LPP), triamcinolone acetonide (TA), and controls. PVR severity was graded on fundoscopic examination using a modified version of the Silicon Study Classification System. Severe PVR was defined as grade 2-5 on this classification, and the proportion of eyes with retinal detachment from severe PVR, defined as retinal re-detachment, i.e., PVR grade 2-5, was compared between treatment and control groups.

Results

On day 28, five eyes (83.3%) in the control group were observed to have severe PVR. Within the LPP group, one (16.7%) eye developed retinal detachment due to severe PVR. Grade 0 PVR was observed in four (66.7%) eyes, grade 1 in one (16.7%) eye, and grade 5 in one (16.7%) eye. Within the TA group, grade 0 PVR was observed in four eyes (66.7%), grade 1 in two eyes (16.6%), and grade 5 in one (16.7%) eye. The difference in the proportion of eyes with severe PVR was significantly lower in the LPP group compared to controls at day 28 (16.7% vs 83.3%, p=0.02). There was no significant difference in the rate of severe PVR or median PVR grade between the liposomal prednisolone phosphate and triamcinolone acetonide groups.

Conclusion

Liposomal prednisolone phosphate reduces the severity of PVR in a minipig model of PVR.

A randomised controlled trial of adjunctive triamcinolone acetonide in eyes undergoing vitreoretinal surgery for open globe trauma - the ASCOT study

Background

Eyes sustaining open globe trauma are at high risk of severe visual impairment. Proliferative vitreoretinopathy is the most common cause of retinal detachment and visual loss in eyes with open globe trauma. There is evidence from experimental studies and pilot clinical trials that the use of adjunctive steroid medication triamcinolone acetonide can reduce the incidence of proliferative vitreoretinopathy and improve outcomes of surgery for open globe trauma.

Objective

The Adjunctive Steroid Combination in Ocular Trauma or ASCOT study aimed to investigate the clinical effectiveness of adjunctive triamcinolone acetonide given at the time of vitreoretinal surgery for open globe trauma.

Design

A phase 3 multicentre double-masked randomised controlled trial randomising patients undergoing vitrectomy following open globe trauma to either adjunctive triamcinolone acetonide or standard care.

Setting

Hospital vitreoretinal surgical services dealing with open globe trauma.

Participants

Patients undergoing vitrectomy surgery who had sustained open globe trauma.

Interventions

Triamcinolone acetonide 4 mg/0.1 ml into the vitreous cavity and 40 mg/1 ml sub-Tenon's or standard vitreoretinal surgery and postoperative care.

Main outcome measures

The primary outcome was the proportion of patients with at least 10 letters of improvement in corrected visual acuity at six months. Secondary outcomes included retinal detachment secondary to proliferative vitreoretinopathy, retinal reattachment, macula reattachment, tractional retinal detachment, number of operations, hypotony, elevated intraocular pressure and quality of life. Health-related quality of life was assessed using the EuroQol Five Domain and Visual Function Questionnaire 25 questionnaires.

Results

A total of 280 patients were randomised; 129 were analysed from the control group and 130 from the treatment group. The treatment group appeared, by chance, to have more severe pathology on presentation. The primary outcome (improvement in visual acuity) and principal secondary outcome (change in visual acuity) did not demonstrate any treatment benefit for triamcinolone acetonide. The proportion of patients with improvement in visual acuity was 47% for triamcinolone acetonide and 43% for standard care (odds ratio 1.03, 95% confidence interval 0.61 to 1.75, p = 0.908); the baseline adjusted mean difference in the six-month change in visual acuity was -2.65 (95% confidence interval -9.22 to 3.92, p = 0.430) for triamcinolone acetonide relative to control. Similarly, the secondary outcome measures failed to show any treatment benefit. For two of the secondary outcome measures, stable complete retinal reattachment and stable macular retinal reattachment, outcomes for the treatment group were significantly worse for triamcinolone acetonide at the 5% level (respectively, odds ratio 0.59, 95% confidence interval 0.36 to 0.99, p = 0.044 and odds ratio 0.59, 95% confidence interval 0.35 to 0.98, p = 0.041) compared with control in favour of control. The cost of the intervention was £132 per patient. Health economics outcome measures (Early Treatment Diabetic Retinopathy Study, Visual Function Questionnaire 25 and EuroQol Five Dimensions) did not demonstrate any significant difference in quality-adjusted life-years.

Conclusions

The use of combined intraocular and sub-Tenon's capsule triamcinolone acetonide is not recommended as an adjunct to vitrectomy surgery for intraocular trauma. Secondary outcome measures are suggestive of a negative effect of the adjunct, although the treatment group appeared to have more severe pathology on presentation.

Future work

The use of alternative adjunctive medications in cases undergoing surgery for open globe trauma should be investigated. Refinement of clinical grading and case selection will enable better trail design for future studies.

Trial registration

This trial is registered as ISRCTN 30012492, EudraCT number 2014-002193-37, REC 14/LNO/1428, IRAS 156358, Local R&D registration CHAD 1031.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (12/35/64) and will be published in full in Health Technology Assessment; Vol. 27, No. 12. See the NIHR Journals Library website for further project information.

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

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

Incidence of Epiretinal Membrane Formation After Pars Plana Vitrectomy for Giant Retinal Tear-Associated Retinal Detachment

Objective

To report the incidence of postoperative epiretinal membrane (ERM) formation after primary pars plana vitrectomy (PPV) for giant retinal tear associated retinal detachment (GRT-RD) repair as well as its clinical characteristics and visual outcomes at a level one trauma and tertiary referral academic center.

Patients and Methods

Patients with primary RD repair for GRT-RD at West Virginia University from September 2010 to July 2021 were identified using the ICD-10 codes (H33.031, H33.032, H33.033 and H33.039). Imaging studies including optical coherence tomography (OCT) were manually reviewed pre- and post-operatively for ERM formation after PPV for GRT-RD repair in patients who underwent PPV or combined PPV and scleral buckle (SB). Univariate analysis was performed to analyze clinical factors for ERM formation.

Results

The study included 17 eyes of 16 patients who underwent PPV for GRT-RD. Postoperative ERM was observed in 70.6% (13 of 17 eyes) of the patients. Anatomic success was achieved in all patients. The mean (range) preoperative and final best corrected visual acuity (BCVA) in logMAR units by macula status was 0.19 (0-0.5) and 0.28 (0-0.5) for macula-on and 1.7 (0.5-2.3) and 0.7 (0.2-1.9) for macular-off GRT-RDs. Clinical variables including use of medium-term tamponade with perfluorocarbon liquid (PFCL), cryopexy, endodiathermy, number of tears or total clock hours of tears did not correlate with an increased risk of ERM formation.

Conclusion

Post-vitrectomized eyes for GRT-RD repair have a significantly higher incidence of ERM formation, nearing 70% in our study. Surgeons may consider prophylactic ILM peel at the time of removal of tamponade agents or weigh in ILM peel at the time of primary repair, a more challenging surgical technique in our opinion.

Advances in Polysaccharide- and Synthetic Polymer-Based Vitreous Substitutes

The vitreous humour is a gel-like structure that composes the majority of each eye. It functions to provide passage of light, be a viscoelastic dampener, and hold the retina in place. Vitreous liquefaction causes retinal detachment and retinal tears requiring pars plana vitrectomy for vitreous substitution. An ideal vitreous substitute should display similar mechanical, chemical, and rheological properties to the natural vitreous. Currently used vitreous substitutes such as silicone oil, perfluorocarbon liquids, and gases cannot be used long-term due to adverse effects such as poor retention time, cytotoxicity, and cataract formation. Long-term, experimental vitreous substitutes composed of natural, modified and synthetic polymers are currently being studied. This review discusses current long- and short-term vitreous substitutes and the disadvantages of these that have highlighted the need for an ideal vitreous substitute. The review subsequently focuses specifically on currently used polysaccharide- and synthetic polymer-based vitreous substitutes, which may be modified or functionalised, or employed as the derivative, and discusses experimental vitreous substitutes in these classes. The advantages and challenges associated with the use of polymeric substitutes are discussed. Innovative approaches to vitreous substitution, namely a novel foldable capsular vitreous body, are presented, as well as future perspectives related to the advancement of this field.

Hyalocytes in proliferative vitreo-retinal diseases

Introduction

Hyalocytes are sentinel macrophages residing within the posterior vitreous cortex anterior to the retinal inner limiting membrane (ILM). Following anomalous PVD and vitreoschisis, hyalocytes contribute to paucicellular (vitreo-macular traction syndrome, macular holes) and hypercellular (macular pucker, proliferative vitreo-retinopathy, proliferative diabetic vitreo-retinopathy) diseases.

Areas covered

Studies of human tissues employing dark-field, phase, and electron microscopy; immunohistochemistry; and in vivo imaging of human hyalocytes.

Expert opinion

Hyalocytes are important in early pathophysiology, stimulating cell migration and proliferation, as well as subsequent membrane contraction and vitreo-retinal traction. Targeting hyalocytes early could mitigate advanced disease. Ultimately, eliminating the role of vitreous and hyalocytes may prevent proliferative vitreo-retinal diseases entirely.

Vitreous Substitutes as Drug Release Systems

Vitreous substitutes are traditionally used to stabilize the retina after vitrectomy. In recent years, various approaches have been developed for using the vitreous substitute not only as a tamponade but also as a drug release system to tackle ocular diseases. This review provides an overview of the requirements for vitreous substitutes and discusses the current clinically applied as well as novel polymer-based vitreous substitutes as drug delivery systems, including their release mechanisms, efficiencies, challenges, and future perspectives.

Proteomic Insight into the Role of Exosomes in Proliferative Vitreoretinopathy Development

Purpose: To characterize vitreous humor (VH) exosomes and to explore their role in the development of proliferative vitreoretinopathy (PVR) using mass spectrometry-based proteome profiling. Methods: Exosomes were isolated from undiluted VH from patients with retinal detachment (RD) with various stages of PVR (n = 9), macular hole (MH; n = 5), or epiretinal membrane (ERM; n = 5) using differential ultracentrifugation. The exosomal size, morphology, and exosome markers were analyzed using a nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and an exosome detection antibody array. The tryptic fragment sequencing of exosome-contained proteins was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a Thermo Lumos Fusion Tribrid Orbitrap mass spectrometer. The pathway analysis of the MS data was performed. Results: The number of exosome particles were significantly increased only in the RD with severe PVR group compared with the control groups and the RD without PVR or with mild PVR groups. Of 724 exosome proteins identified, 382 were differentially expressed (DE) and 176 were uniquely present in PVR. Both DE proteins and exosome proteins that were only present in PVR were enriched in proteins associated with previously known key pathways related to PVR development, including reactive retinal gliosis, pathologic cellular proliferation, inflammation, growth of connective tissues, and epithelial mesenchymal transition (EMT). The SPP1, CLU, VCAN, COL2A1, and SEMA7A that are significantly upregulated in PVR were related to the tissue remodeling. Conclusions: Exosomes may play a key role in mediating tissue remodeling along with a complex set of pathways involved in PVR development.

Combined 5-Fluorouracil and Low Molecular Weight Heparin for the Prevention of Postoperative Proliferative Vitreoretinopathy in Patients With Retinal Detachment: A Meta-Analysis

Background: Postoperative proliferative vitreoretinopathy (PVR) remains a dilemma for retinal surgeons. We performed a literature search and meta-analyses to figure out whether combined 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) treatment were effective in improving the primary success of vitrectomy and preventing postoperative PVR occurrence in patients with retinal detachment (RD).

Methods: Databases including PubMed, Embase, the Cochrane library, and China National Knowledge Infrastructure (CNKI) were searched from inception to May 2021. Comparative studies approaching the effects of combined 5-FU and LMWH on postoperative PVR were included. Quality assessment was performed using RoB 2 and ROBINS-I tool. Study data were pooled using Review manager 5.4.1. The main outcomes were: the primary success of vitrectomy at 6 months and the postoperative PVR occurrence. The additional outcomes were: number of patients who underwent vitreoretinal reoperations and the number of vitreoretinal reoperations due to postoperative PVR. Subgroup analyses and sensitivity analyses were also performed.

Results: Six clinical trials with a total of 1,208 participants were included. We found that combined 5-FU and LMWH infusion did not improve the primary success of vitrectomy at 6 months (RR = 1.00, 95% CI = 0.95, 1.07, P = 0.89, I² = 50%). Also, the conjunct therapy had no effect on reducing the number of patients who underwent vitreoretinal reoperations (RR = 1.00, 95% CI = 0.78, 1.28, P = 1.00, I² = 42%). The overall effect of the treatment on preventing postoperative PVR was negative. However, in patients with PVR grade C (PVRC) before intervention, the 5-FU and LMWH treatment significantly reduced PVR occurrence. Visual acuity was not different between the treatment and control groups. Nevertheless, in one RCT, a significant reduction of VA was observed in the treatment group in macular-sparing patients with RD. No complications were attributed to the conjunct therapy.

Conclusions: The combined 5-FU and LMWH treatment neither improved the primary success of vitrectomy at 6 months nor decreased number of patients who underwent vitreoretinal reoperations. Thus, the treatment should not be routinely used in vitrectomy for patients with RD. However, the treatment proved beneficial in reducing postoperative PVR in patients with PVRC before intervention. More high-quality clinical trials are needed to confirm the results.

Systematic Review Registration:https://inplasy.com/inplasy-2021-8-0117/, identifier: INPLASY202180117.

Doxycycline Ameliorates the Severity of Experimental Proliferative Vitreoretinopathy in Mice

After successful surgeries for patients with rhegmatogenous retinal detachment, the most common cause of retinal redetachment is proliferative vitreoretinopathy (PVR), which causes severe vision impairment and even blindness worldwide. Until now, the major treatment for PVR is surgical removal of the epiretinal membrane, while effective treatment to prevent PVR is still unavailable. Therefore, we investigated the potential of doxycycline, an antibiotic in the tetracycline class, to treat PVR using a mouse model. We used the human retinal pigment epithelial cell line, ARPE-19, for in vitro and in vivo studies to test doxycycline for PVR treatment. We found that doxycycline suppressed the migration, proliferation, and contraction of ARPE-19 cells with reduced p38 MAPK activation and total MMP activity. Intravitreal doxycycline and topical tetracycline treatment significantly ameliorated the PVR severity induced by ARPE-19 cells in mice. PVR increased the expression of MMP-9 and IL-4 and p38 MAPK phosphorylation and modestly decreased IL-10. These effects were reversed by doxycycline and tetracycline treatment in the mouse retina. These results suggest that doxycycline will be a potential treatment for PVR in the future.

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.

Pharmacotherapy as an adjunct to vitrectomy

Vitreoretinal surgery has advanced extensively from the first days of vitrectomy. During the last decade, new developments in intravitreal pharmacotherapy have created new opportunities to enhance the surgical outcomes of our patients. In this article, we review and discuss some of the supporting evidence of different pharmacotherapies that may be used as an adjunct to vitrectomy for select common etiologies. Triamcinolone acetonide, dexamethasone, and angiogenesis inhibitors are among the most commonly used drugs given their safety profile and proven efficacy. Other pharmaceuticals have also shown promising results in small studies. The adoption of individualized medical treatments prior, during, and after vitrectomy will continue to increase as new evidence supporting the benefit of pharmacotherapy as an adjunct to vitrectomy becomes available.

Electronic retinal prosthesis for severe loss of vision in geographic atrophy in age-related macular degeneration: First-in-human use

BACKGROUND

To date there are yet no available approved therapies for Geographic Atrophy (GA) secondary to age-related macular degeneration (AMD).

METHODS

Single site, non-randomized safety and efficacy study presenting the preliminary results in a cohort of five late stage AMD (GA) patients successfully implanted with the Argus II Retinal Prosthesis System (Second Sight Medical Products Inc., Sylmar, CA, USA). Extensive fundus imaging including retinal photographs from which the GA area was measured. A combination of custom and traditional tests designed for very low vision subjects assessed visual function in study subjects. A Functional Low-Vision Observer Rated Assessment was carried out to evaluate the impact of the system on the subject's daily life. In addition, a study to evaluate structural characteristics of the visual cortex of the brain was performed in one subject using magnetic resonance imaging.

RESULTS

Seven device-related adverse events were reported, four of which were classed as serious adverse events. Retinal detachment was reported in three patients and was successfully treated within 12 months of onset. Testing showed an improvement in visual function in three of five patients with the system turned on. Magnetic resonance imaging assessed in one patient after implantation indicates a selective increase in cortical myelin and thickness in visual brain regions 1 year post implantation.

CONCLUSIONS

Epiretinal prostheses can successfully be implanted in those affected by GA secondary to late-stage AMD and can elicit visual percepts by electrical stimulation of residual neuroretinal elements and improve basic visual function in those affected.

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.

Salinomycin inhibits proliferative vitreoretinopathy formation in a mouse model

Proliferative vitreoretinopathy (PVR) is a progressive disease that develops in a subset of patients who undergo surgery for retinal detachment repair, and results in significant vision loss. PVR is characterized by the migration of retinal pigment epithelial (RPE) cells into the vitreous cavity, where they undergo epithelial-to-mesenchymal transition and form contractile membranes within the vitreous and along the retina, resulting in recurrent retinal detachments. Currently, surgical intervention is the only treatment for PVR and there are no pharmacological agents that effectively inhibit or prevent PVR formation. Here, we show that a single intravitreal injection of the polyether ionophore salinomycin (SNC) effectively inhibits the formation of PVR in a mouse model with no evidence of retinal toxicity. After 4 weeks, fundus photography and optical coherence tomography (OCT) demonstrated development of mean PVR grade of 3.5 (SD: 1.3) in mouse eyes injected with RPE cells/DMSO (vehicle), compared to mean PVR grade of 1.6 (SD: 1.3) in eyes injected with RPE cells/SNC (p = 0.001). Additionally, immunohistochemistry analysis showed RPE cells/SNC treatment reduced both fibrotic (αSMA, FN1, Vim) and inflammatory (GFAP, CD3, CD20) markers compared to control RPE cells/DMSO treatment. Finally, qPCR analysis confirmed that Tgfβ, Tnfα, Mcp1 (inflammatory/cytokine markers), and Fn1, Col1a1 and Acta2 (fibrotic markers) were significantly attenuated in the RPE cells/SNC group compared to RPE/DMSO control. These results suggest that SNC is a potential pharmacologic agent for the prevention of PVR in humans and warrants further investigation.

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.

[Melfalan in the treatment of proliferative vitreoretinopathy (experimental study)]

PURPOSE

To study of the effectiveness of the drug Melphalan as an antiproliferative agent during experimental proliferative vitreoretinopathy (PVR).

MATERIAL AND METHODS

The experimental study used data from 24 eyes of 12 Chinchilla rabbits weighing 2.5-3.0 kg, which had PVR modeled in both eyes by intravitreal injection of a culture of heterogeneous activated fibroblast cells consisting of 200,000 cells in 0.1 ml. Treatment of experimental PVR was performed 1 day after the modeling process. In the first group of animals (6 eyes), 0.02 mg of Melphalan was administered intravitreally. In the second group of animals (6 eyes), 0.005 mg of Melphalan concentrated in 0.1 ml was administered intravitreally. Left eyes in both groups remained without treatment. Animals were observed for 1 month using biomicroscopy and ophthalmoscopy. 30 days after the animals were removed from the experiment, the eyes were enucleated, fixed in 10% buffered formalin and subjected to standard histological examination. The study of paraffin sections of the eyes was performed using the microscopic system «Leica» (Leica Microsystems, Germany) with built-in digital camera at the magnification of 200-600.

RESULTS

In groups 1 and 2 of the study in the eyes of rabbits that received treatment, PVR was absent, unlike the eyes without treatment, where PVR remained. In group 1, where the dose of Melphalan was 0.02 mg in 0.1 ml, there were changes in the RPE (retinal pigment epithelium), which was regarded as a retinotoxic effect. Glial degeneration and thinning of the retina with disappearance of the photoreceptor layer (the outer nuclear and plexiform layers) resulted from the disturbance of retinal metabolism caused by RPE destruction. In group 2, structure of the retina remained more intact: isolated foci were noted with a decrease in the volume of the outer nuclear layer, shortening of rods and cones with preservation of the inner layers of the retina.

CONCLUSION

A single intravitreal injection of 0.005 mg Melphalan had a positive therapeutic antiproliferative effect on the PVR model with minimal retinotoxic changes.

Position of macula lutea and presence of proliferative vitreoretinopathy affect vitreous cytokine expression in rhegmatogenous retinal detachment

Our purpose was to evaluate the concentrations of vitreous cytokines in patients with rhegmatogenous retinal detachment (RRD). We hypothesized that patients with macula on RRD have lower levels of cytokines compared to patients with macula off RRD and proliferative vitreoretinopathy (PVR). Vitreous fluids were collected during 23G pars plana vitrectomy from 58 eyes of 58 patients. Indication for vitrectomy included macula off and macula on RRD, PVR, and idiopathic epiretinal membrane (ERM). A multiplex chemiluminescent immunoassay was performed to measure the concentrations of 48 cytokines, chemokines, and growth factors. Levels of HGF, IL-6, IL-8, IL-16, IFN-gamma, MCP-1, and MIF were significantly higher in all groups of retinal detachment compared to ERM. Levels of CTACK, eotaxin, G-CSF, IP-10, MIG, SCF, SCGF-beta, SDF-1alpha were significantly higher in PVR compared to macula on RRD and ERM. Levels of IL-1ra, IL-5, IL-9, M-CSF, MIP-1alpha, and TRIAL were significantly higher in PVR compared to macula on RRD. Our results indicate that the position of macula lutea and the presence of PVR significantly influence vitreous cytokine expression. The detected proteins may serve as biomarkers to estimate the possibility of PVR formation and may help to invent personalized therapeutic strategies to slow down or prevent PVR.

Inflammatory mediators of proliferative vitreoretinopathy: hypothesis and review

Purpose

To review the role of inflammatory mediators in proliferative vitreoretinopathy (PVR) development and the current treatment for PVR prevention.

Methods

A PubMed search was carried out using these keywords “PVR,” “inflammatory mediators,” “growth factors,” “cytokines” and “treatment.” Studies regarding inflammatory mediators and PVR therapy were included and published up to December 2019.

Results

Inflammatory mediators, namely growth factors and cytokines, have been implicated in the occurrence and development of PVR. Among various inflammatory mediators, transforming growth factor-β, platelet-derived growth factor, interleukin-6, interleukin-8 and tumor necrosis factor-α are considered to be particularly important. In this review, we focus on the hypothesis that growth factors and cytokines are involved in the development of PVR, and current treatment for the prevention of PVR.

Conclusion

We support the hypothesis that growth factors and cytokines may participate in the complex process of PVR development. More importantly, the identification of inflammatory mediators provides novel and efficacious therapeutic targets for the treatment of PVR.

Proliferative vitreoretinopathy: revised concepts of pathogenesis and adjunctive treatment

Proliferative vitreoretinopathy (PVR) remains a significant challenge for vitreoretinal surgeons. Its incidence, as a complication of retinal detachment, does not appear to have altered despite improvement in surgical techniques. Extensive laboratory research has been undertaken to investigate the pathogenesis of PVR and the use of adjunctive mediations to modify the disease process. To date these studies have not resulted in improved clinical management of PVR. Previous concepts of the pathogenesis of PVR, focussing on a central role for RPE cells, may be flawed and could potentially have contributed to the lack of clinical advances. Revised clinical classifications and novel approaches to adjunctive treatment may in the future result in improved surgical outcomes.

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.

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.

Intraocular application of Mitomycin C to prevent proliferative vitreoretinopathy in perforating and severe intraocular foreign body injuries

AIM

To assess the long-term anatomical and functional outcomes in addition to complications of a new surgical technique of localized intraocular application of mitomycin C (MMC) to prevent proliferative vitreoretinopathy (PVR) in eyes with open globe trauma.

METHODS

Prospective non-comparative interventional case series of 16 consecutive eyes with perforating and deep choroidal impact foreign body injuries presenting over a 2-year period. Patients underwent vitrectomy with intraocular application of MMC at the site of the chorioretinal injury and were followed-up for 1 year. The primary outcome measure was the rate of postoperative PVR. Secondary outcome measures were number of vitreoretinal surgeries (VRS) required, best corrected visual acuity (BCVA), final anatomical success rate and globe survival rate (GSR).

RESULTS

Patients underwent VRS at a mean time of 8.5 ± 4.6 days after the injury. Postoperative PVR developed in 2 (13 %) eyes and required only one additional VRS each. One other eye underwent further peeling of an epimacular membrane. BCVA improved from mean LogMAR 3.08 ± 0.72 preoperatively to 0.66 ± 0.79 at 1 year. All 10 eyes without a macular injury had a final BCVA of LogMAR 0.40 or better. The final anatomical success rate was 94% and GSR rate was 100%. There were no complications related to the intraocular use of MMC.

CONCLUSIONS

Vitrectomy and intraocular application of Mitomycin C may have a potential role in reducing the rate of post traumatic PVR and improving anatomical and functional outcomes in eyes with perforating and deep choroidal impact foreign body injuries.

Utility of Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium for an In Vitro Model of Proliferative Vitreoretinopathy

The advent of stem cell technology, including the technology to induce pluripotency in somatic cells, and direct differentiation of stem cells into specific somatic cell types, has created an exciting new field of scientific research. Much of the work with pluripotent stem (PS) cells has been focused on the exploration and exploitation of their potential as cells/tissue replacement therapies for personalized medicine. However, PS and stem cell-derived somatic cells are also proving to be valuable tools to study disease pathology and tissue-specific responses to injury. High-throughput drug screening assays using tissue-specific injury models have the potential to identify specific and effective treatments that will promote wound healing. Retinal pigment epithelium (RPE) derived from induced pluripotent stem cells (iPS-RPE) are well characterized cells that exhibit the phenotype and functions of in vivo RPE. In addition to their role as a source of cells to replace damaged or diseased RPE, iPS-RPE provide a robust platform for in vitro drug screening to identify novel therapeutics to promote healing and repair of ocular tissues after injury. Proliferative vitreoretinopathy (PVR) is an abnormal wound healing process that occurs after retinal tears or detachments. In this chapter, the role of iPS-RPE in the development of an in vitro model of PVR is described. Comprehensive analyses of the iPS-RPE response to injury suggests that these cells provide a physiologically relevant tool to investigate the cellular mechanisms of the three phases of PVR pathology: migration, proliferation, and contraction. This in vitro model will provide valuable information regarding cellular wound healing responses specific to RPE and enable the identification of effective therapeutics.

Crocetin inhibits PDGF-BB-induced proliferation and migration of retinal pigment epithelial cells

In proliferative vitreoretinopathy (PVR), the proliferation and migration of retinal pigment epithelial (RPE) cells are important to pathogenesis. Platelet-derived growth factor (PDGF) is an important factor in the underlying mechanism. Several studies have shown that PDGF induced the proliferation and migration effects on RPE cells in PVR. Crocetin-anantioxidant carotenoid that is abundant in saffron-has been shown to suppress the migration and proliferation of many cell types, but studies of the effects on RPE cell migration and proliferation are incomplete. Therefore, we investigated the inhibitory effect of crocetin on the proliferation and migration of ARPE-19 cells induced by PDGF-BB, an isoform of PDGF. The proliferation of cells was assessed by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays. The apoptosis of cells was assessed by flow cytometric analysis. The migration of RPE cells was detected by a Transwell migration assay and an in vitro scratch assay. The levels of main regulatory proteins for apoptosis and the PDGF-BB-induced signaling pathway were determined by western blot analysis. The proliferation and migration of ARPE-19 cells treated with crocetin (100-400 μM) and PDGF-BB (20 ng/ml) were significantly inhibited in a concentration- and time-dependent manner. Crocetin exhibited potent inducing effects on the apoptosis of PDGF-BB-induced ARPE-19 cells via the modulation of Bcl-2 family regulators in a concentration-dependent manner. The inhibitory effects of crocetin on PDGF-BB-induced platelet-derived growth factor receptor β (PDGFRβ) and the underlying pathways of PI3K/Akt and ERK, p38, JNK activation were identified. The results showed that crocetin is an effective inhibitor of PDGF-BB-induced proliferation and migration of ARPE-19 cell through the downregulation of regulatory signaling pathways.

Determining the effect of low-dose isotretinoin on proliferative vitreoretinopathy: the DELIVER trial

PURPOSE

To examine the effect of low-dose, oral isotretinoin in lowering the risk of proliferative vitreoretinopathy (PVR) following rhegmatogenous retinal detachment (RRD) repair.

METHODS

Prospective, open label, dual-cohort study with pathology-matched historical controls. The prospective experimental arms included two cohorts, composed of 51 eyes with recurrent PVR-related RRD and 58 eyes with primary RRD associated with high-risk features for developing PVR. Eyes in the experimental arms received 20 mg of isotretinoin by mouth once daily for 12 weeks starting the day after surgical repair. The primary outcome measure was single surgery anatomical success rate at 3 months following the study surgery.

RESULTS

The single surgery anatomic success rate was 78.4% versus 70.0% (p=0.358) in eyes with recurrent PVR-related retinal detachment exposed to isotretinoin versus historical controls, respectively. In eyes with RRD at high risk for developing PVR, the single surgery success rate was 84.5% versus 61.1% (p=0.005) for eyes exposed to isotretinoin versus historical controls, respectively. For eyes enrolled in the experimental arms, the most common isotretinoin-related side effects were dry skin/mucus membranes in 106 patients (97.2%), abnormal sleep/dreams in 4 patients (3.7%) and fatigue in 3 patients (2.8%).

CONCLUSION

The management and prevention of PVR is challenging and complex. At the dose and duration given in this study, oral istotretinoin may reduce the risk of PVR-associated recurrent retinal detachment in eyes with primary RRD at high risk of developing PVR.

5-Fluorouracyl added infusion fluid in patients with recurrent rhegmatogeneous retinal detachment

Purpose

To compare the efficacy of 5-fluorouracil (5-FU) added the infusion fluid with a control group in the event of grade C PVR in recurrent retinal detachment (RD).

Methods

The records of the patients with recurrent retinal detachment with grade C PVR who underwent vitrectomy for retinal detachment surgery between April 2003 and October 2004 were reviewed retrospectively for this comparative study. The recurrent retinal detachment patients with grade C PVR who underwent vitrectomy and had a minimum post-operative follow-up period of 12 months were included. The patients were divided into two groups as study and control groups. 5-FU (200 microgram/ml) and low-molecular-weight-heparin (LMWH) (5 IU/ml) was added into the infusion solution of the study group. Primary outcome measure of this study was the single operation anatomical success at month 12.

Results

A total of 43 eyes of 43 patients were included. The control group was consisted of 26 eyes (60.5%) and the 5-FU group was consisted of 17 eyes (39.5%). At month 12, single operation anatomical success was obtained in 14 of the 26 patients (53.8%) in the control group and in 16 of the 17 patients (94.1%) in the 5-FU group (p = 0.005).

Conclusion

Favorable outcomes were obtained in the patients with recurrent RD and grade C PVR in whom 5-FU and LMWH added infusion fluid which was used during vitrectomy.

Dabigatran inhibits intravitreal thrombin activity

PURPOSE

Proliferative vitreoretinopathy (PVR) is a vitreoretinal disorder in which retinal pigment epithelial (RPE) cell activation contributes to both formation of fibrotic retinal membranes and inflammation. Vitreous of patients with PVR contains increased thrombin activity which induces profibrotic and proinflammatory programs in RPE cells. Inhibition of intravitreal thrombin activity may thus represent a therapeutic option for PVR. In this study, we examined the capacity of the clinically available direct thrombin inhibitor dabigatran to inhibit thrombin activity in vitreous fluids.

METHODS

ARPE-19 cells were cultured with the following: (i) thrombin, (ii) vitreous without thrombin activity and (iii) vitreous with elevated thrombin activity (PVR samples and thrombin spiked vitreous) either in the presence or absence of dabigatran (range: 10^-5 to 10^-7  M). Subsequently, CCL2, CXCL8, GMCSF, IL6 and PDGFB mRNA expression levels were determined by RQ-PCR and protein levels of 27 cytokines, chemokines and growth factors were detected in culture supernatants using a multiplex approach. In addition, the capacity of vitreous fluids obtained from patients after oral dabigatran intake was tested in an in vitro thrombin activity assay.

RESULTS

Thrombin and vitreous fluids containing thrombin activity induced CCL2, CXCL8, GM-CSF, IL-6 and PDGF-BB expression by ARPE-19 cells, which was inhibited by dabigatran. In addition, dabigatran that reached the vitreous after repeated oral intake did inhibit thrombin activity in the in vitro activity assay.

CONCLUSION

Proliferative vitreoretinopathy (PVR) is associated with increased intravitreal thrombin activity that activates profibrotic and proinflammatory pathways in RPE cells. Our findings provide evidence that this activation pathway can potentially be inhibited by dabigatran.

Prophylactic intravitreal 5-fluorouracil and heparin to prevent proliferative vitreoretinopathy in high-risk patients with retinal detachment: study protocol for a randomized controlled trial

BACKGROUND

Proliferative vitreoretinopathy (PVR) is the major cause for postoperative failure after vitreo-retinal surgery for primary rhegmatogenous retinal detachment (RRD). Adjunct pharmaceutical therapy was found to be ineffective once PVR is established. Preliminary data suggest that prevention of PVR yields better functional outcome. So far, there is no standard therapy to prevent PVR.

METHODS/DESIGN

This is a randomized, double-blind, controlled, multicenter, interventional trial with one interim analysis. High-risk patients for PVR with primary RRD will be allocated equally to the following treatment arms: (a) verum: intraoperative adjuvant application of 5-fluorouracil (5-FU) and low-molecular-weight heparin (LMWH) via intraocular infusion during routine pars plana vitrectomy (PPV) and (b) placebo: routinely used intraocular infusion with balanced salt solution during routine PPV. PVR risk is assessed by non-invasive aqueous flare measurement by using laser flare photometry. The primary endpoint of the trial is the occurrence of PVR grade CP (C: full-thickness retinal folds or subretinal strands in clock hours; P: located posterior to equator) 1 or higher within 12 weeks after treatment. Secondary endpoints include PVR grade CA (A: located anterior to equator), best corrected visual acuity, number and extent of surgical procedures to achieve retinal re-attachment, and occurrence of drug-related adverse events within 12 weeks. It is assumed, on the basis of previously published results, that the incidence of PVR grade CP 1 is 35% in the control group and that a reduction by one third would be clinically relevant. Given the sequential design and adjustment for a dropout rate of 5%, a total sample size of 560 patients (280 per group) was calculated to ensure a power of 80% for the confirmatory analysis.

DISCUSSION

The present trial uses intraoperative intravitreal 5-FU and LMWH as a prophylactic therapy in high-risk patients with primary RRD, aiming to reduce the incidence of PVR in the group that receives the trial drug. Using laser flare photometry to identify high-risk patients for PVR, this trial will test the effectiveness of a simple treatment to prevent PVR.

TRIAL REGISTRATION

EudraCT no.: 2015-004731-12, registered October 21, 2015; ClinicalTrials.gov Identifier: NCT02834559 , registered July 12, 2016. Protocol version: Version 02. Date: September 18, 2016.

Surgery for postvitrectomy cataract

BACKGROUND

Cataract formation or acceleration can occur after intraocular surgery, especially following vitrectomy, a surgical technique for removing the vitreous that is used in the treatment of many disorders that affect the posterior segment of the eye. The underlying problem that led to vitrectomy may limit the benefit from removal of the cataractous lens.

OBJECTIVES

To evaluate the effectiveness and safety of surgery versus no surgery for postvitrectomy cataract with respect to visual acuity, quality of life, and other outcomes.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 5), MEDLINE Ovid (1946 to 17 May 2017), Embase.com (1947 to 17 May 2017), PubMed (1946 to 17 May 2017), Latin American and Caribbean Health Sciences Literature database (LILACS) (January 1982 to 17 May 2017), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com); last searched May 2013, ClinicalTrials.gov (www.clinicaltrials.gov); searched 17 May 2017, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 17 May 2017. We did not use any date or language restrictions in the electronic searches for trials.

SELECTION CRITERIA

We planned to include randomized controlled trials (RCTs) and quasi-RCTs that had compared surgery versus no surgery to remove the lens from eyes of adults in which cataracts had developed following vitrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results according to the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We found no RCTs or quasi-RCTs that had compared surgery versus no surgery to remove the lens from eyes of adults in which cataracts had developed following vitrectomy.

AUTHORS' CONCLUSIONS

There is no evidence from RCTs or quasi-RCTs on which to base clinical recommendations for surgery for postvitrectomy cataract. There is a clear need for RCTs to address this evidence gap. Such trials should stratify participants by their age, the retinal disorder leading to vitrectomy, and the status of the underlying disease process in the contralateral eye. Outcomes assessed in such trials may include changes (both gains and losses) of visual acuity, quality of life, and adverse events such as posterior capsular rupture and retinal detachment. Both short-term (six-month) and long-term (one- or two-year) outcomes should be examined.

Evaluation of the Effect of Everolimus on Retinal Pigment Epithelial Cells and Experimental Proliferative Vitreoretinopathy

PURPOSE

Failure of retinal detachment surgery is most commonly due to the development of proliferative vitreoretinopathy (PVR). Everolimus is an inhibitor of mammalian target of rapamycin (mTOR), and is available as oral tablets. In this study, we investigated the effect of everolimus on retinal pigment epithelial cells and modification of the severity of experimental PVR.

METHODS

In our in vitro studies, primary culture of retinal pigment epithelium (RPE) cells was obtained from pigmented Rex rabbits. Cell proliferation was assayed with the tetrazolium dye cytotoxicity test, and cell migration assay was performed in 24-well transwell units with 8-μm filters. In the in vivo study, pigmented Rex rabbits weighing between 2 and 2.5 kg were used. Each rabbit eye underwent gas compression; one week later, 5 × 10⁴ RPE cells were injected into the vitreous cavity to induce PVR, and each eye was graded with indirect ophthalmoscopy on days 1, 3, 7, 14, 21, and 28. The rabbits were administered everolimus (0.5 mg/day orally) from the day of PVR induction. Total proteins extracted from RPE cells and dissected retinal samples were processed for Western blotting analysis of mTOR and ribosomal protein S6 (RPS6).

RESULTS

The in vitro studies showed that everolimus significantly inhibited the proliferation of RPE cells at 0.1 μg/ml; additionally, at 10 μg/ml, it suppressed the migration of RPE cells and significantly suppressed the expression of mTOR and RPS6 in RPE cells. The in vivo study did not show any benefit of oral everolimus (0.5 mg/day) in suppressing experimental PVR. Thus, everolimus significantly suppressed the expression of mTOR and RPS6 in PVR.

CONCLUSIONS

Everolimus suppressed the proliferation and migration of RPE cells in vitro. Oral everolimus (0.5 mg/day) suppressed the expression of mTOR and RPS6 in the retina, but showed no effect in suppressing experimental PVR.