Vitreous from idiopathic epiretinal membrane patients induces glial-to-mesenchymal transition in Müller cells.

Idiopathic epiretinal membranes (ERMs) are fibrocellular membranes containing extracellular matrix proteins and epiretinal cells of retinal and extraretinal origin. iERMs lead to decreased visual acuity and their pathogenesis has not been completely defined. Macroglial Müller cells appear to play a pivotal role in the pathogenesis of iERM where they may undergo glial-to-mesenchymal transition (GMT), a transdifferentiation process characterized by the downregulation of Müller cell markers, paralleled by the upregulation of pro-fibrotic myofibroblast markers. Previous observations from our laboratory allowed the molecular identification of two major clusters of iERM patients (named iERM-A and iERM-B), iERM-A patients being characterized by less severe clinical features and a more "quiescent" iERM gene expression profile when compared to iERM-B patients. In the present work, Müller MIO-M1 cells were exposed to vitreous samples obtained before membrane peeling from the same cohort of iERM-A and iERM-B patients. The results demonstrate that iERM vitreous induces proliferation, migration, and GMT in MIO-M1 cells, a phenotype consistent with Müller cell behavior during iERM progression. However, even though the vitreous samples obtained from iERM-A patients were able to induce a complete GMT in MIO-M1 cells, iERM-B samples caused only a partial GMT, characterized by the downregulation of Müller cell markers in the absence of upregulation of pro-fibrotic myofibroblast markers. Together, the results indicate that a relationship may exist among the ability of iERM vitreous to modulate GMT in Müller cells, the molecular profile of the corresponding iERMs, and the clinical features of iERM patients.

Gene expression analysis identifies two distinct molecular clusters of idiopatic epiretinal membranes.

Idiopathic epiretinal membranes (ERMs) are fibrocellular membranes containing extracellular matrix proteins and epiretinal cells of retinal and extraretinal origin. iERMs lead to decreased visual acuity and their pathogenesis has not been completely defined. Aim of this study was to provide a molecular characterization of iERMs by gene expression analysis. To this purpose, 56 iERMs obtained by pars plana vitrectomy were analyzed for the expression levels of genes encoding biomarkers of the cellular and molecular events occurring in iERMs. RT-qPCR analysis showed significant differences in the levels of cell population, extracellular matrix and cytokine/growth factor biomarkers among the iERMs investigated. Hierarchical clustering of RT-qPCR data identified two distinct iERM clusters, Cluster B samples representing transcriptionally "activated" iERMs when compared to transcriptionally "quiescent" Cluster A specimens. Further, Cluster B could be subdivided in two subgroups, Cluster B1 iERMs, characterized by a marked glial cell activation, and Cluster B2 samples characterized by a more pro-fibrotic phenotype. Preoperative decimal best-corrected visual acuity and post-surgery inner segment/outer grading values were higher in Cluster A patients, that showed a prevalence of fovea-attached type iERMs with near-normal inner retina, than in Cluster B patients, that presented more severe clinical and spectral domain optical coherence tomography (SD-OCT) features. In conclusion, this molecular characterization has identified two major clusters of iERM specimens with distinct transcriptional activities that reflect different clinical and SD-OCT features of iERM patients. This retrospective work paves the way to prospective whole-genome transcriptomic studies to allow a molecular classification of iERMs and for the identification of molecular signature(s) of prognostic and therapeutic significance.

FOVEA-SPARING VERSUS COMPLETE INTERNAL LIMITING MEMBRANE PEELING IN VITRECTOMY FOR THE TREATMENT OF MACULAR HOLES.

PURPOSE: To compare the anatomical and functional outcomes of vitrectomy involving complete internal limiting membrane peeling (CP) with those of vitrectomy involving fovea-sparing internal limiting membrane peeling (FSP) for the treatment of macular holes measuring >250 µm. METHODS: This prospective, randomized, comparative study included 46 eyes with a medium or large macular hole that was randomized to undergo complete (CP group) or fovea-sparing (FSP group) internal limiting membrane peeling during vitrectomy. The main outcome measures included the foveal retinal sensitivity, visual acuity, and central retinal thickness. RESULTS: Both groups showed significantly improved foveal retinal sensitivity after surgery; the mean foveal retinal sensitivity change at 12 months after surgery was +2.8 ± 2.1 dB in the CP group and +7.2 ± 2.3 dB in the FSP group. The visual acuity also showed a significant improvement in both groups, with no significant differences in values at any time point. Regarding central retinal thickness, there was a significant decrease in the CP group and no change in the FSP group. Nicks or dimples in the inner retinal layers were visible in the fovea and perifovea of nine eyes in the CP group. CONCLUSION: Our findings suggest that both CP and FSP are safe and effective treatments leading to functional and anatomical improvements in patients with all size macular holes. However, the fovea-sparing technique may provide better functional outcomes because of a greater improvement in foveal retinal sensitivity.

PEELING OF THE INTERNAL LIMITING MEMBRANE WITH FOVEAL SPARING FOR TREATMENT OF DEGENERATIVE LAMELLAR MACULAR HOLE.

PURPOSE: To compare the functional and anatomical results of fovea-sparing internal limiting membrane peeling during vitrectomy with those of observation for degenerative lamellar macular hole with lamellar hole-associated epiretinal proliferation. DESIGN: A prospective, randomized, comparative pilot study. METHODS: Thirty-six eyes were randomized to undergo surgery with foveal internal limiting membrane sparing (Group S) or observation only (Group C). The main outcome measures were foveal retinal sensitivity, visual acuity, and central retinal thickness. RESULTS: After 6 months, a significant difference was found in foveal retinal sensitivity between Group S (12.8 ± 1.7 dB) and Group C (9.39 ± 1.8 dB; P < 0.001). Similarly, best-corrected visual acuity improved in Group S and remained stable in Group C (respectively, 0.17 ± 0.13 and 0.46 ± 0.21 logMAR; P < 0.001). A significant increase in central retinal thickness was observed in Group S, but not in Group C (272 ± 24 vs. 147 ± 20 µm, P < 0.001). CONCLUSION: Fovea-sparing internal limiting membrane peeling is a feasible treatment for degenerative lamellar macular hole with lamellar hole-associated epiretinal proliferation, yielding better improvements in best-corrected visual acuity and foveal retinal sensitivity than observation alone. Further studies are needed to optimize this new surgical approach.

Central Serous Chorioretinopathy: Pathogenesis and Management.

Central serous chorioretinopathy (CSC) is a common retina disease and has a relative high recurrence rate, etiology, and pathogenesis of which remains largely ambiguous. The effects on the retina are usually self-limited, although some people are left with permanent vision loss due to progressive and irreversible photoreceptor damage or retinal pigment epithelium atrophy. There have been a number of interventions used in CSC, including, but not limited to, laser treatment, photodynamic therapy (PDT), intravitreal injection of anti-vascular endothelial growth factor agents, and subthreshold lasers. It is not clear whether there is a clinically important benefit to treating acute CSC, which often resolves spontaneously as part of its natural history. Of the interventions studied to date, PDT and micropulse laser treatment appear the most promising. .

Comparative assessment of intraocular inflammation following standard or heavy silicone oil tamponade: a prospective study.

PURPOSE: To evaluate the inflammation associated with the use of standard silicone oil (polydimethylsiloxane; PDMS) and heavy silicone oil (HSO) Densiron-68™ in patients undergoing vitrectomy for retinal detachment. MATERIALS AND METHODS: A prospective study was performed involving 35 patients scheduled to undergo vitrectomy for retinal detachment. Patients received PDMS or Densiron-68™ HSO according to superior or inferior retinal localization of the tears, respectively. For assessing the inflammation, prostaglandin E2 (PGE2 ) and interleukin-1α (IL-1α) levels were evaluated in the aqueous. RESULTS: Thirty-five eyes of 35 patients completed the study: 20 eyes received HSO, and 15 eyes received PDMS. The mean aqueous PGE2 level was significantly higher in HSO patients than in PDMS patients (869.16 ± 242.83 pg/ml versus 369.38 ± 209.7 pg/ml, respectively; p < 0.0001). The mean aqueous IL-1α level was also significantly higher in HSO patients than in PDMS patients (81.40 ± 36.9 pg/ml versus 40.8 ± 32.5 pg/ml, respectively; p = 0.002). In HSO, a moderate positive correlation between the endotamponade duration and both PGE2 (r = 0.44; p = 0.05) and IL-1α (r = 0.48; p = 0.033) levels was observed. In PDMS, a strong positive correlation between the endotamponade duration and both PGE2 (r = 0.89; p < 0.0001) and IL-1α (r = 0.68; p = 0.006) levels was observed. CONCLUSION: Although both HSO and PDMS yielded favourable success rates in the surgical treatment of complicated retinal detachments, HSO triggered a more severe inflammatory reaction, in a time-dependent manner.

EPIRETINAL MEMBRANE REMOVAL WITH FOVEAL-SPARING INTERNAL LIMITING MEMBRANE PEELING: A Pilot Study.

PURPOSE: To compare the retinal sensitivity after complete internal limiting membrane (ILM) peeling with that after foveal-sparing ILM peeling during vitrectomy for Type I epiretinal membrane. METHODS: This was a prospective, randomized, comparative study. Thirty-eight eyes were randomized to undergo complete peeling of the ILM (CP group) or peeling with foveal sparing (FS group). The main outcome measures were foveal and perifoveal retinal sensitivity, visual acuity, and central retinal thickness. RESULTS: Foveal retinal sensitivity showed a significant improvement in the FS group (2.82 ± 0.85 dB, P = 0.037) versus a slight drop in the CP group (-0.66 ± 0.48 dB, P = 1). Perifoveal retinal sensitivity slightly improved in both groups (0.47 ± 0.37 dB, P = 1 in the CP group and 0.79 ± 0.42 dB, P = 0.77 in the FS group), showing a similar trend without significant differences. Significant improvements were observed in both visual acuity and central retinal thickness in both groups. However, three cases in the FS group showed epiretinal membrane recurrence and required revision surgery with complete ILM removal. CONCLUSION: Internal limiting membrane peeling may reduce retinal sensitivity and significantly increase the incidence of microscotomas. However, the higher epiretinal membrane recurrence rate after the foveal-sparing technique limits the effectiveness of this procedure. Further studies must be conducted to determine if it is safe to leave a portion of the ILM in front of the fovea.

Combination of ranibizumab and indomethacin for neovascular age-related macular degeneration: randomized controlled trial.

PURPOSE: The aim of this study was to evaluate whether indomethacin eye drops and intravitreal ranibizumab (IVR) injections would provide additional benefit over ranibizumab alone in the treatment of choroidal neovascularization (CNV). PARTICIPANTS AND METHODS: This was a randomized, prospective pilot study of eyes with new-onset CNV. Fifty-eight patients were randomized 1:1 into a ranibizumab monotherapy (RM) group and a ranibizumab plus indomethacin (RI) group. All patients received monthly 0.5 mg IVR injections for 3 months, followed by monthly injections administered as needed. RI group patients also self-administered one drop of 0.5% indomethacin three times a day for 12 months. All patients were followed up for 12 months. RESULTS: At 12 months, both groups showed significant improvement in best-corrected visual acuity (BCVA) and central retinal thickness (CRT). The mean BCVA change from baseline to 12 months was -0.12±0.04 LogMAR and -0.20±0.04 LogMAR in the RM and RI groups, respectively, with the degree of change being significantly different between the two groups (P=0.04). At 12 months, the mean CRT in the RM group (316±41.2 µm) was significantly higher than that in the RI group (287±31.5 µm; P=0.004). The mean required number of IVR injections was 7.38±0.78 and 6.34±0.67 in the RM and RI groups, respectively (P<0.001). CONCLUSION: Compared to IVR monotherapy, combination therapy with indomethacin eye drops and IVR provides superior anatomical and visual outcomes in patients with naive CNV lesions. Moreover, topical indomethacin might reduce the frequency of IVR injections, which is very beneficial considering the chronic and expensive nature of IVR therapy.

Heavy and standard silicone oil: intraocular inflammation.

PURPOSE: Proliferative vitreoretinopathy in the inferior retina remains clinically challenging. Heavier-than-water intraocular tamponades have been developed to improve inferior tamponading properties, and their chemical compositions have been substantially improved over the years, in parallel with developments in vitrectomy instrumentation and surgical techniques. Herein we present an updated review of the clinical use of standard formulations and HSO, focusing on analysis of the intraocular inflammation associated with endotamponade agents, and comparison of the adverse effects of these agents on the physical and biological properties of the eye. METHODS: A detailed literature search was conducted on PubMed, EMBASE, Cochrane Library, and Google Scholar using the key words. Fifty-eight articles matched our inclusion criteria that were included in this systematic review. RESULTS: Perfluorocarbon liquids and partially fluorinated alkanes are associated with tamponade emulsification, intraocular inflammation, and rises in intraocular pressure, but these associations are not as strong when these substances are mixed with a heavy silicone oil (HSO). Two recently approved heavy silicone oil tamponades, Oxane HD and Densiron 68, are now available for use in clinical practice. While the complication spectrum of the new generation of these HSOs seems to be similar to that of conventional silicone oil tamponades, they provide better support for the inferior retina and the posterior pole. CONCLUSION: Both regular and heavy silicone oils usually yield good success rates in cases of complicated retinal detachment. Decisions as to whether to utilize heavy or regular silicone oil should be made on a case-by-case basis.

Comparison of half-dose photodynamic therapy and 689 nm laser treatment in eyes with chronic central serous chorioretinopathy.

PURPOSE: To compare visual and anatomical outcomes between half-dose photodynamic therapy (hd-PDT) and 689 nm laser therapy (689-LT) in chronic central serous chorioretinopathy (CSC). METHODS: Forty eyes of 40 patients with symptomatic chronic CSC were randomized in a 1:1 ratio to receive either hd-PDT or 689-LT delivering 95 J/cm2 via an intensity application of 805 mW/cm2 over 118 s. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography findings were compared between the two treatment groups. RESULTS: Mean CSC duration was 17.1 ± 6.66 weeks and 18.7 ± 7.46 weeks in the hd-PDT and 689-LT groups respectively. Both groups showed significant BCVA improvements, as well as reductions in central retinal and subfoveal choroidal thickness. Although hd-PDT led to a faster reduction in central retinal thickness, no significant differences were recorded between groups for any other measured parameter at any time point. Complete photoreceptor recovery was observed in eight and seven eyes in the hd-PDT and 689-LT groups respectively. CONCLUSIONS: Both hd-PDT and 689-LT were effective at treating chronic CSC. Further studies are warranted to evaluate long-term safety and efficacy.

Controversies over the role of internal limiting membrane peeling during vitrectomy in macular hole surgery.

Surgical management of an idiopathic macular hole consists of vitrectomy to release vitreofoveal traction and intraocular tamponade to flatten and reappose the hole's edges. The intentional atraumatic removal of the internal limiting membrane has been proposed as cost-effective option in macular hole surgery. The internal limiting membrane contributes to tangential traction at the edges of the hole and acts as a platform on which glial cells proliferate. Removal of the internal limiting membrane increases the elasticity of the denuded macula and improves the anatomical success rate; however, the visual consequences of this surgical maneuver are still not fully known. We discuss the beneficial and adverse effects associated with internal limiting membrane peeling in macular hole surgery, highlighting the internal limiting membrane's role in macular hole etiology and pathogenesis and the anatomical and functional findings after its removal.

From the analysis of pharmacologic vitreolysis to the comprehension of ocriplasmin safety.

INTRODUCTION: Pharmacologic vitreolysis is a strategy used to treat anomalous posterior vitreous detachment, by weakening vitreoretinal adhesion with an intravitreal drug. Pharmacologic vitreolysis facilitates surgery, and abnormalities of the vitreoretinal interface including vitreomacular traction (VMT) and early stage macular hole (MH) could be resolved. Ocriplasmin is a recombinant protease, active against fibronectin and laminin, which are important components of the vitreoretinal interface. Ocriplasmin has been approved for symptomatic treatment of VMT and MH with visible traction, and it functions by dissolving the proteins that link the vitreous to the macula, thereby creating a complete posterior vitreous detachment (PVD). AREAS COVERED: This paper reviews the current knowledge and status of investigations regarding the use of ocriplasmin for pharmacologic vitreolysis and its safety. EXPERT OPINION: Ocriplasmin is a non-specific enzyme; therefore, it dissolves vitreal proteins as well as possibly proteins associated with visual function in the retina, choroid, and lens. Ocular adverse events (OAEs) of ocriplasmin include transient visual loss, intraocular inflammation, vitreous floaters, lens opacification, zonular instability of the lens, and intraocular hemorrhage. The prevalence of the OAEs is very low; however, on rare occasions, they can result in widespread retinal dysfunction. Research into the acute and long-term safety of ocriplasmin is required.

Current Trends about Inner Limiting Membrane Peeling in Surgery for Epiretinal Membranes.

The inner limiting membrane (ILM) is the basement membrane of the Müller cells and can act as a scaffold for cellular proliferation in the pathophysiology of disorders affecting the vitreomacular interface. The atraumatic removal of the macular ILM has been proposed for treating various forms of tractional maculopathy in particular for macular pucker. In the last decade, the removal of ILM has become a routine practice in the surgery of the epiretinal membranes (ERMs), with good anatomical results. However many recent studies showed that ILM peeling is a procedure that can cause immediate traumatic effects and progressive modification on the underlying inner retinal layers. Moreover, it is unclear whether ILM peeling is helpful to improve vision after surgery for ERM. In this review, we describe the current understanding about ILM peeling and highlight the beneficial and adverse effects associated with this surgical procedure.

Pharmacokinetic and Pharmacodynamic Properties of Anti-VEGF Drugs After Intravitreal Injection.

Subretinal neovascularization and pathologic ocular angiogenesis are common causes of progressive, irreversible impairment of central vision, and dramatically affect quality of life. Anti-vascular endothelial growth factor (anti-VEGF) therapy has improved the quality of life for many patients with age-related macular degeneration, diabetic retinopathy, and other ocular diseases involving neovascularization and edema. In these pathologies, the inhibition of intraocular VEGF is the only therapy that can preserve vision. Four anti-VEGF drugs are currently used to treat ocular neovascularization; pegaptanib, ranibizumab, and aflibercept have been approved for this condition, while bevacizumab can be used off-label. Anti-VEGF therapy is administered regularly for many months or years because its suspension or discontinuation may cause recurrence of neovascularization. On the other hand, VEGF is necessary for the survival of retinal and choroidal endothelial cells. Experimental studies in animal models have shown that local inhibition of VEGF causes thinning and atrophy of the choriocapillaris and degeneration of photoreceptors, primarily cones. These studies combined with clinical experience indicated that prolonged VEGF inhibition could impair retinal function. Moreover, anti-VEGF compounds can cross the blood-retina barrier, enter the systemic circulation, and inhibit serum VEGF. Since circulating VEGF protects blood vessel integrity, prolonged anti-VEGF treatment could induce thromboembolic adverse events from vascular causes such as heart attack and stroke, and even death. The ocular dosing regimen and systemic toxicity of anti-VEGF compounds are therefore central concerns. A better understanding of this topic requires knowledge of the metabolism, tissue distribution, and clearance of anti-VEGF compounds. This manuscript reviews the properties of anti-VEGF compounds following intravitreal administration.

Efficacy and vitreous levels of topical NSAIDs.

INTRODUCTION: Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed medications and are routinely used for their analgesic, antipyretic, and anti-inflammatory properties. Because of their potent cyclooxygenase-inhibitory activity, they can inhibit pro-inflammatory prostaglandin synthesis, leading to complex inflammatory cascades. NSAIDs have been broadly used systemically for many decades and have recently become commercially available in the form of topical ophthalmic formulations. NSAIDs are weak acids with pKa values mostly between 3.5 and 4.5 and are poorly water-soluble. New, aqueous ophthalmic solutions of NSAIDs that afford better tissue penetration have recently been developed. In ophthalmological practice, topical NSAIDs are mostly used to stabilize pupillary dilation during intraocular surgery, manage postoperative pain and inflammation, and treat pseudophakic cystoid macular edema. AREAS COVERED: This review focuses on the vitreous penetration of topical NSAIDs and their potential clinical applications in the treatment of retinal diseases. EXPERT OPINION: A growing body of evidence suggests that NSAIDs may be beneficial in the treatment of age-related macular degeneration, diabetic retinopathy, and ocular tumors. Recent studies from our group and other authors have shown that the vitreous levels of NSAID exceed the median inhibitory concentration, which can significantly decrease vitreous PGE2 levels.

Heavy silicone oil and intraocular inflammation.

In the past two decades, many advances have been made in vitrectomy instrumentation, surgical techniques, and the use of different tamponade agents. These agents serve close retinal breaks, confine eventual retinal redetachment, and prevent proliferative vitreoretinopathy (PVR). Long-acting gases and silicone oil are effective internal tamponade agents; however, because their specific gravity is lower than that of the vitreous fluid, they may provide adequate support for the superior retina but lack efficacy for the inferior retina, especially when the fill is subtotal. Thus, a specific role may exist for an internal tamponade agent with a higher specific gravity, such as heavy silicone oils (HSOs), Densiron 68, Oxane HD, HWS 45-300, HWS 46-3000, and HeavySil. Some clinical evidence seems to presume that heavy tamponades are more prone to intraocular inflammation than standard silicone if they remain in the eye for several months. In this review, we discuss the fundamental clinical and biochemical/molecular mechanisms involved in the inflammatory response after the use of heavy tamponade: toxicity due to impurities or instability of the agent, direct toxicity and immunogenicity, oil emulsification, and mechanical injury due to gravity. The physical and chemical properties of various HSOs and their efficacy and safety profiles are also described.

Systemic thromboembolic adverse events in patients treated with intravitreal anti-VEGF drugs for neovascular age-related macular degeneration: an overview.

INTRODUCTION: Anti-VEGF therapy improved the quality of life for millions of patients suffering from wet age-related macular degeneration (wet-AMD); unfortunately, this therapy involves multiple injections over many years. The administration of anti-VEGF can overcome the blood-retinal barrier with agents entering the systemic circulation and causing a significant decrease in VEGF serum concentration. Although circulating VEGF protects the integrity and patency of vessels, prolonged anti-VEGF treatment has the potential to increase the risk of thromboembolic events. AREAS COVERED: In this review, we discuss the safety data from recent trials involving available anti-VEGF drugs. EXPERT OPINION: During the 2 years of follow-up in the relevant clinical trials, the rates of serious adverse events such as stroke, heart attack and death were similar for patients treated with different anti-VEGF drugs. Moreover the arterial thrombotic risk appears sufficiently low when compared with the natural incidence of arterial thrombotic events in this category of elderly patients and acceptably balanced against the advantage of improved vision. Since the use of these drugs is likely to become increasingly widespread and prolonged, it is desirable that the scientific community improves the pharmacovigilance program on all anti-VEGF drugs, expanding knowledge with studies that compares head to head all four compounds belonging to anti-VEGF armamentarium.

Proliferative vitreoretinopathy after eye injuries: an overexpression of growth factors and cytokines leading to a retinal keloid.

Eye injury is a significant disabling worldwide health problem. Proliferative Vitreoretinopathy (PVR) is a common complication that develops in up to 40-60% of patients with an open-globe injury. Our knowledge about the pathogenesis of PVR has improved in the last decades. It seems that the introduction of immune cells into the vitreous, like in penetrating ocular trauma, triggers the production of growth factors and cytokines that come in contact with intra-retinal cells, like Müller cells and RPE cells. Growth factors and cytokines drive the cellular responses leading to PVR's development. Knowledge of the pathobiological and pathophysiological mechanisms involved in posttraumatic PVR is increasing the possibilities of management, and it is hoped that in the future our treatment strategies will evolve, in particular adopting a multidrug approach, and become even more effective in vision recovery. This paper reviews the current literature and clinical trial data on the pathogenesis of PVR and its correlation with ocular trauma and describes the biochemical/molecular events that will be fundamental for the development of novel treatment strategies. This literature review included PubMed articles published from 1979 through 2013. Only studies written in English were included.