Microplasmin Degrades Fibronectin and Laminin at Vitreoretinal Interface and Outer Retina during Enzymatic Vitrectomy

Vitrectomy and ILM peeling in rhesus macaque: pitfalls and tips for success

BACKGROUND

The non-human primate (NHP) model is ideal for pre-clinical testing of novel therapies for human retinal diseases due to its similarity to the human visual system. However, intra-ocular delivery of gene therapy or cell transplantation to the retina gets hampered by the sticky vitreous body and poorly permeable inner limiting membrane (ILM) in primates. Although vitrectomy and ILM peeling are commonly performed in patients, many pitfalls exist in carrying out these procedures in the rhesus macaque, which have not been reported previously.

METHODS

We summarised common surgical pitfalls after performing vitrectomy and ILM peeling in four eyes of two rhesus macaques (one male and one female). We provided corresponding hands-on technical tips based on our surgical experience and literature search. Orbital CT scans were compared between adult rhesus macaques and humans. High-resolution surgical videos were recorded to demonstrate each critical surgical step.

RESULTS

Due to size difference, poor post-operative compliance, and high-standard requirements of a controlled experiment, there were eleven common surgical pitfalls during vitrectomy and ILM peeling in rhesus macaque. Falling into these pitfalls may produce discomfort, add fatigue, cause surgical complications, or even lead to the exclusion of the NHP from an experimental group.

CONCLUSION

Recognition and circumvention of these pitfalls during vitrectomy and ILM peeling in NHP are essential. By focusing on these surgical pitfalls, we can better carry out preclinical tests of novel therapies for retinal diseases in the NHP model.

A novel recombinant human microplasminogen induced complete posterior vitreous detachment without morphological change of retina in juvenile rabbits

Vitreomacular traction syndrome results from persistent vitreoretinal adhesions in the setting of partial posterior vitreous detachment (PVD). Vitrectomy and reattachment of retina is an effective therapeutic approach. The adhesion between vitreous cortex and internal limiting membrane (ILM) of the retina is stronger in youth, which brings difficulties to induce PVD in vitrectomy. Several clinical investigations demonstrated that intravitreous injection of plasmin before vitrectomy could reduce the risk of detachment. In our study, a novel recombinant human microplasminogen (rhμPlg) was expressed by Pichia pastoris. Molecular docking showed that the binding of rhμPlg with tissue plasminogen activator (t-PA) was similar to plasminogen, suggesting rh μPlg could be activated by t-PA to generate microplasmin (μPlm). Moreover, rhμPlg had higher catalytic activity than plasminogen in amidolytic assays. Complete PVD was found at vitreous posterior pole of 125 μg rhμPlg-treated eyes without morphological change of retina in juvenile rabbits via intraocular injection. Our results demonstrate that rhμPlg has a potential value in the treatment of vitreoretinopathy.

The Effect of Intravitreal Ocriplasmin on Hue Discrimination

SIGNIFICANCE

We report 13 patients who received ocriplasmin for symptomatic vitreomacular adhesion. Farnsworth-Munsell 100 (FM 100) hue test total error score (TES) increased from baseline to month 1, before recovering at year 1. Ocriplasmin may alter hue discrimination.

PURPOSE

This study aimed to determine whether intravitreal ocriplasmin affects hue discrimination.

METHODS

Thirteen patients with symptomatic vitreomacular adhesion received intravitreal ocriplasmin 125 μg. Patients underwent full ocular examination, optical coherence tomography, and FM 100 hue test at baseline, 1 week, 1 month, and 1 year.

RESULTS

Mean age was 74.8 years. The median baseline FM 100 TES was similar in the injected and fellow eyes (272 vs. 252, respectively). Median TES in the injected eye increased from 272 to 348 at 1 week (median difference compared with baseline, +52.0; 98.8% confidence interval of difference, -64.0 to 184.0; P = .29), decreased to 324 at 1 month (median difference compared with baseline, -4.0; 98.8% confidence interval of difference, -44.0 to 256.0; P = .40), and decreased to 268 at 1 year (median difference compared with baseline, -108.0; 93.8% confidence interval of difference, -200.0 to 52.0; P = .19). Two patients (15.4%) had anatomic release of vitreomacular adhesion, occurring within 1 month of injection.

CONCLUSIONS

Ocriplasmin may alter hue discrimination, but larger studies are required to provide sufficient power to detect or exclude a statistically significant effect. Longer follow-up is needed to determine the duration of any effect.

Visual functional changes after ocriplasmin injection for vitreomacular traction: A microperimetric analysis

PURPOSE:

The purpose is to evaluate functional changes after ocriplasmin injection to treat vitreomacular traction (VMT) by microperimetry.

MATERIALS AND METHODS:

Prospective interventional study on patients underwent an intravitreal ocriplasmin injection. Optical coherence tomography, best-corrected visual acuity (BCVA) test, and microperimetry were performed at baseline, 1 week, 1 and 3 months. Microperimeter recorded retinal sensitivity (RS) and central retinal sensitivity (CRS) at central 12° and 4°, respectively, and fixation as bivariate contour ellipse area (BCEA) at 68%, 95%, and 99% of fixation points. Functional parameters were analyzed in patients who had (Group A) or not (Group B) VMT release.

RESULTS:

Twenty-one patients including 18 with VMT and 3 with VMT plus macular hole (MH) were treated. Eleven patients achieved VMT resolution including all cases with MH that achieved hole closure. An impairment of BCVA, RS and CRS (P < 0.01; P < 0.001; P = 0.001, respectively) was reported at 1 week followed by a significant improvement (BCVA, P = 0.001; RS, CRS, P = 0.02) at 3 months. The early impairment of visual acuity and sensitivity significantly occurred in Group B (P ≤ 0.01) while their recovery significantly occurred in Group A (P < 0.01). BCEA significantly increased in dimension (68%, P = 0.01; 95%, P = 0.03) at 1 week, subsequently returning to near baseline values over follow-up. Only in Group A, fixation stability significantly improved at 3 months.

CONCLUSION:

Microperimetry confirms an early and reversible functional impairment after ocriplasmin injection regardless VMT resolution. If a greater decrease in function could occur in the eyes without VMT resolution, a better functional recovery could occur in the event of VMT resolution.

Assessment of E. coli Expression System for Overexpression of Active Recombinant Ocriplasmin

Purpose: Ocriplasmin (Jetrea TM) is a FDA approved recombinant enzyme utilized in the treatment of vitreomacular adhesion (VMA). This is a recombinant C-terminal fragment of human plasmin produced using yeast Pichia pastoris. Since ocriplasmin does not contain any Oor N-glycosylation or some other post-translational modifications, bacterial expression systems such as Escherichia coli could be considered as an economical host for recombinant expression. In the present study, we aimed to evaluate the efficiency of E. coli expression system for highlevel expression of recombinant ocriplasmin.

Methods: The gene coding for ocriplasmin was cloned and expressed in E. coli BL21. The bacterial cells were cultured on large scale and the expressed recombinant protein was purified using Ni-NTA chromatography. Refolding of denatured ocriplasmin to active enzyme was carried out by the stepwise removal of denaturant. The identity of recombinant ocriplasmin was confirmed using western blotting and ELISA assays. The presence of the active ocriplasmin was monitored by the hydrolytic activity assay against the chromogenic substrate S-2403.

Results: The final yield of E. coli BL21-produced ocriplasmin was approximately 1 mg/mL which was greater than that of P. pastoris. Using western blotting and ELISA assay, the identity of recombinant ocriplasmin was confirmed. The hydrolysis of chromogenic substrate S-2403 verified the functional activity of E. coli produced ocriplasmin.

Conclusion: The results of this study indicated that E. coli could be used for high level expression of ocriplasmin. Although the recombinant protein was expressed as inclusion body, the stepwise refolding leads to the biologically active proteins.

Post hoc analysis of ellipsoid zone changes beyond the central subfield in symptomatic vitreomacular adhesion patients from the OASIS trial

Background/aims

OASIS is a Phase IIIb trial (NCT01429441) assessing long-term outcomes in subjects with symptomatic vitreomacular adhesion (VMA). The purpose of this study is to report on the frequency, severity, location and time course of ellipsoid zone (EZ) alterations in ocriplasmin-treated and sham control eyes in the OASIS study.

Methods

220 patients (146 ocriplasmin, 74 sham) subjects with VMA were enrolled in this masked post hoc analysis phase IIIb, randomised, sham-controlled double-masked multicentre clinical trial. A masked post hoc analysis of OCT images was performed at the Doheny Image Reading Center from subjects enrolled in the OASIS trial. The status of the EZ band was assessed in three different macular regions: the central subfield (CS) (≤1 mm diameter), the parafoveal area (PAA) (>1 to ≤3 mm) and the perifoveal area (PEA) (>3 to ≤6 mm). The EZ band was rated as normal/intact, full thickness macular hole (FTMH), abnormal but continuous, discontinuous/disrupted or absent at visits from baseline (pretreatment) to week 1 (day 7), month 1 (day 28), month 3, month 6, month 12 and the final follow-up at month 24. EZ band status was compared in both study and control eyes.

Results

A total of 208 patients (138 ocriplasmin, 70 sham) were included in this analysis. At baseline, FTMH was present in 48.6%, 8.0%, 0% and 52.8%, 2.9%, 0% in the CS, PAA and PEA of the ocriplasmin and sham groups, respectively. The EZ was graded to be abnormal but continuous, discontinuous/disrupted or absent at Baseline in 21.0%, 4.3%, 2.8% in the CS, PAA and PEA, respectively, of the ocriplasmin group; and 12.9%, 10.0%, 4.3% in the CS, PAA and PEA of the sham group. For the ocriplasmin group in the PAA, this frequency increased to 6.6% at week 1, was 9.8% at month 1, but improved to 3.8% at month 3, and remained stable to 1.6% at month 24. These differences, however, were not statistically significant.

Conclusions

Ocriplasmin treatment for symptomatic VMA was associated with EZ abnormalities in a small percentage of patients that was best assessed in regions (PEA) relatively unaffected by the VM interface disease at baseline. The EZ abnormalities were apparent by week 1, persisted at month 1, and appeared to resolve in the majority of cases by month 3.

Trial registration number

NCT01429441

Identification of key genes and pathways in scleral extracellular matrix remodeling in glaucoma: Potential therapeutic agents discovered using bioinformatics analysis

Background: Glaucoma is a leading cause of irreversible blindness. Remodeling of the scleral extracellular matrix (ECM) plays an important role in the development of glaucoma. The aim of this study was to identify the key genes and pathways for the ECM remodeling of sclera in glaucoma by bioinformatics analysis and to explore potential therapeutic agents for glaucoma management. Methods: Genes associated with glaucoma, sclera and ECM remodeling were detected using the text mining tool pubmed2ensembl, and assigned Gene Ontology (GO) biological process terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using the GeneCodis program. A protein-protein interaction (PPI) network was constructed by STRING and visualized in Cytoscape, module analysis was performed using the Molecular Complex Detection (MCODE) plugin, and GO and KEGG analyses of the gene modules were performed using the Database of Annotation, Visualization and Integrated Discovery (DAVID) platform. The genes that clustered in the significant module were selected as core genes, and functions and pathways of the core genes were visualized using ClueGO and CluePedia. Lastly, the drug-gene interaction database was used to explore drug-gene interactions of the core genes to find drug candidates for glaucoma. Results: We identified 125 genes common to "Glaucoma", "Sclera", and "ECM remodeling" by text mining. Gene functional enrichment analysis yielded 30 enriched GO terms and 20 associated KEGG pathways. A PPI network that included 60 nodes with 249 edges was constructed, and three gene modules were obtained using the MCODE. We selected 13 genes that clustered in module 1 as core candidate genes that were associated mainly with ECM degradation and cell proliferation and division. The HIF-1 signaling pathway, FOXO signaling pathway, PI3K-Akt signaling pathway and TGFB signaling pathway were found to be enriched. We found that 11 of the 13 selected genes could be targeted by 26 existing drugs. Conclusions: The results showed that VEGFA, TGFB1, TGFB2, TGFB3, IGF2, IGF1, EGF, FN1, KNG1, TIMP1, SERPINE1, THBS1, and VWF were potential key genes involved to scleral ECM remodeling. Furthermore, 26 drugs were identified as potential therapeutic agents for glaucoma treatment and management.

Vitreomacular traction quantitative cutoffs for the assessment of resolution after ocriplasmin intravitreal treatment

This study aimed to assess optical coherence tomography (OCT) parameters associated with vitreomacular traction (VMT) resolution after ocriplasmin intravitreal injection and also associated with the development of vitreomacular complications. Study designed was a retrospective case series. Structural OCT images were acquired at baseline and over the follow-up after treatment. We developed a mathematical model to provide quantitative parameters associated with VMT resolution. Moreover, we adopted the same model to assess the quantitative parameters associated with development of further vitreomacular complications or with the worsening of the coexisting condition. Main outcome measures were BCVA, central macular thickness (CMT), VMT reflectivity, VMT size, VMT resolution, epiretinal membrane (ERM), macular holes. 73 eyes of 73 VMT patients (mean age 73 ± 9 years) were recruited. The mean follow-up duration was 2.6 ± 1.1 years. Mean baseline BCVA was 0.38 ± 0.18 LogMAR, improving to 0.26 ± 0.20 at the end of the follow-up (p < 0.01). Baseline CMT was 431 ± 118 µm, improving to 393 ± 122 µm at the end of the follow-up (p < 0.01). 38/73 eyes (52%) showed only VMT, whereas 35/73 eyes (48%) also showed coexisting alterations at baseline. VMT resolved in 40/73 eyes (55% of cases). Our model disclosed VMT reflectivity as the most involved parameter in VMT resolution. VMT size showed less influence on the success of ocriplasmin treatment. ERM was negatively associated with VMT resolution. Moreover, VMT reflectivity values and ERM represented the most important parameters for the onset of vitreomacular complications.

A time-dependent study of nano-mechanical and ultrastructural properties of internal limiting membrane under ocriplasmin treatment

Vitreomacular traction (VMT) syndrome has only been surgically treated for a long time. Recently, enzymatic vitreolysis with ocriplasmin has emerged as a possible option to release VMT and, in some cases, close full thickness macular holes (FTMHs). Despite its clinical relevance, gathering information about the ocriplasmin-induced alterations of the Inner Limiting Membrane (ILM) of the retina in a clinical study is a complex task, mainly because of the inter-individual variability among patients. To obtain more insights into the mechanism underlying the drug action, we studied in-vitro the mechanical and morphological changes of the ILM using Atomic Force Microscopy (AFM). To this aim, we measured the ILM average Young's modulus (YM), hysteresis (H) and adhesion work (A) over time under ocriplasmin treatment. Our data unveil a time-dependent increase in the membrane YM of 19% of its initial value, along with changes in its adhesive and dissipative behavior. Such modifications well correlate with the morphological alterations detected in the AFM imaging mode. Taken all together, the results here presented provide more insights into the mechanism underlying the ocriplasmin action in-vivo, suggesting that it is only able to alter the top-most layer of the vitreal side of the membrane, not compromising the inner ILM structure.

Morphological Reconstitution and Persistent Changes After Intravitreal Ocriplasmin for Vitreomacular Traction and Macular Hole

Purpose: To assess the long-term anatomical and functional findings in patients with symptomatic vitreomacular traction (VMT), with or without full thickness macular hole (FTMH), after eye treatment with intravitreal ocriplasmin injection (IOI). Methods: This longitudinal case series includes 51 eyes from 51 symptomatic patients with VMT (<800 μm) who received a single IOI (Jetrea^® 0.125 mg); 21 cases with an FTMH (<400 μm) were included. Best-corrected visual acuity (BCVA) and optical coherence tomography findings were recorded before IOI, and 1 day to 24 months thereafter. Data are presented as mean ± standard deviation. Results: Mean adhesion size before injection was 345 ± 146 μm. In 34 eyes (67%), complete release of VMT was observed; whereas VMT persisted in 17 eyes (33%). The latter included 15 of the 21 eyes (71%) with FTMH, 15 of which underwent pars plana vitrectomy and inner limiting membrane peeling. BCVA improved from (logarithm of the minimal angle of resolution [logMAR]) 0.41 ± 0.03 before injection to 0.32 ± 0.03 after 1 month and 0.23 ± 0.05 after 6 months and remained stable thereafter (0.24 ± 0.06 after 24 months of follow-up). Forty-five percent of the eyes presented submacular deposits soon after IOI that were not functionally relevant; 61% completely resolved by 12 months. Except floaters that disappeared within 48 h, no other adverse events were reported during follow-up. Conclusions: Treatment with ocriplasmin in a real-life setting showed an overall efficacy of 67% in patients with symptomatic VMT, with better results evident in the absence of an FTMH (70% vs. 62% VMT release) and a visual gain for over 2 years.

Reduced perfusion density of superficial retinal capillary plexus after intravitreal ocriplasmin injection for idiopathic vitreomacular traction

BACKGROUND

To investigate, using optical coherence tomography angiography (OCT-A), changes in perfusion density and in the foveal avascular zone (FAZ) in eyes with idiopathic vitreomacular traction (VMT) after ocriplasmin injection.

METHODS

In this pilot study, we enrolled sixteen VMT eyes treated with intravitreal ocriplasmin injection. Sixteen healthy eyes were considered as controls. Macular perfusion density in 3 plexuses [superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris (CC)] was calculated at baseline and at 1 month after injection.

RESULTS

After injection, VMT anatomically resolved in 9 eyes (56.2%), whereas 7 eyes (43.8%) achieved an incomplete VMT separation. Superficial capillary plexus perfusion density was reduced significantly after injection (from 0.427 ± 0.027 to 0.413 ± 0.028; p = 0.0146), while no differences were noted in the DCP (p = 0.2717) nor in the CC (p = 0.6848). Study-eye perfusion density was statistically similar to control eyes in all three plexuses, both at baseline and at follow-up. The FAZ in the SCP area remained unchanged after injection (p = 0.168) but was significantly inferior to controls both at baseline and at 1 month (0.198 ± 0.074 vs. 0.196 ± 0.070; p = 0.007).

CONCLUSIONS

Eyes with VMT have a perfusion density comparable to healthy controls, but a smaller FAZ. After ocriplasmin injection the perfusion density in the SCP is reduced, regardless the anatomical success. Limited by the small sample size and the pilot nature of the study, we found microvascular changes after ocriplasmin injection, which may be due to retinal traction release.

Subfoveal Lucency after Treatment of Vitreomacular Traction without Macular Hole in the Phase 3 Trials of Ocriplasmin Vitreolysis

PURPOSE

To describe the clinical impact of subfoveal lucency (SFL) seen on OCT before and after treatment of vitreomacular traction (VMT) or symptomatic vitreomacular adhesion (VMA) without macular hole (MH) in the prospective phase 3 trials of ocriplasmin vitreolysis.

DESIGN

Randomized double-blind placebo-controlled multicenter study.

PARTICIPANTS

Four hundred ninety-nine eyes with VMT or VMA without MH.

METHODS

Eyes were randomized to either a single intravitreal injection of ocriplasmin or placebo treatment and were followed up for 6 months.

MAIN OUTCOME MEASURES

Eyes were analyzed for presence, dimensions, and course of SFL on OCT, release of VMT, and their effect on visual acuity (VA).

RESULTS

Among eyes without baseline SFL, new SFL was more frequent after ocriplasmin than placebo at week 1 (23.1% vs. 6.54%; P = 0.0002) and week 2 (19.7% vs. 3.85%; P = 0.0001), but was similar in frequency by week 4 (8.37% vs. 7.69%; P = 0.83). Six-month VA for eyes demonstrating SFL after ocriplasmin during the first 2 weeks was comparable with those without SFL at any point in the study (P = 0.12). In placebo-treated eyes but not ocriplasmin-treated eyes, SFL was associated with worse VA at all visits. The increase in SFL width from baseline to week 2 was significantly greater with ocriplasmin than placebo (P = 0.029). Among ocriplasmin-treated eyes at month 6, those with SFL and VMT release had better VA than those with SFL and persistent adhesion (P = 0.037) and similar VA to those with persistent adhesion without SFL (P = 0.17). In the placebo group, those with baseline SFL showed low rates of spontaneous VMT release at month 6 compared with those without baseline SFL (3/21 eyes vs. 33/99 eyes; P = 0.045).

CONCLUSIONS

Compared with placebo, SFL occurred more frequently only in the initial weeks after treatment with ocriplasmin. When SFL developed after ocriplasmin administration, VA was not impacted at the 6-month visit. Persistent SFL in ocriplasmin-treated eyes at month 6 was associated with poorer vision if VMT had not released. Eyes with SFL at baseline had low rates of spontaneous VMT release and may need treatment.

Pharmacotherapy for Choroidal Neovascularization Due to Uncommon Causes

BACKGROUND

Choroidal neovascularization (CNV) in adults is most commonly associated with neovascular age-related macular degeneration (AMD) and pathologic myopia. Though less common, CNV can also develop from other conditions such as uveitis, central serous chorioretinopathy, angioid streaks, intraocular tumors, hereditary chorioretinal dystrophies, or can be idiopathic in origin. If left untreated, CNV may cause visual loss because of exudation of intraretinal or subretinal fluid, retinal or subretinal hemorrhage, or fibrosis involving the macula. It is well known that one of the main drivers of angiogenesis in CNV development is vascular endothelial growth factor (VEGF) and therefore inhibitors of VEGF might be an effective treatment for CNV.

METHODS

The goal of this review is to provide an overview and summary in the use of pharmacotherapy especially anti-VEGF therapy, in the treatment of CNV due to uncommon causes.

RESULTS

Results from uncontrolled case series and controlled clinical trials have reported good efficacy and safety in using anti-VEGF agents including bevacizumab, ranibizumab, aflibercept and ziv-aflibercept in the treatment of CNV due to uncommon causes. Anti-VEGF has also been used in combination with verteporfin PDT and anti-inflammatory agents for treating CNV of various causes.

CONCLUSION

Pharmacotherapy with anti-VEGF agents is an effective treatment option for CNV due to uncommon etiologies.

Extracellular matrix component expression in human pluripotent stem cell-derived retinal organoids recapitulates retinogenesis in vivo and reveals an important role for IMPG1 and CD44 in the development of photoreceptors and interphotoreceptor matrix

The extracellular matrix (ECM) plays an important role in numerous processes including cellular proliferation, differentiation, migration, maturation, adhesion guidance and axonal growth. To date, there has been no detailed analysis of the ECM distribution during retinal ontogenesis in humans and the functional importance of many ECM components is poorly understood. In this study, the expression of key ECM components in adult mouse and monkey retina, developing and adult human retina and retinal organoids derived from human pluripotent stem cells was studied. Our data indicate that basement membrane ECMs (Fibronectin and Collagen IV) were expressed in Bruch's membrane and the inner limiting membrane of the developing human retina, whilst the hyalectins (Versican and Brevican), cluster of differentiation 44 (CD44), photoreceptor-specific ECMs Interphotoreceptor Matrix Proteoglycan 1 (IMPG1) and Interphotoreceptor Matrix Proteoglycan 2 (IMPG2) were detected in the developing interphotoreceptor matrix (IPM). The expression of IMPG1, Versican and Brevican in the developing IPM was conserved between human developing retina and human pluripotent stem cell-derived retinal organoids. Blocking the action of CD44 and IMPG1 in pluripotent stem cell derived retinal organoids affected the development of photoreceptors, their inner/outer segments and connecting cilia and disrupted IPM formation, with IMPG1 having an earlier and more significant impact. Together, our data suggest an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation during human retinogenesis.

STATEMENT OF SIGNIFICANCE

The expression and the role of many extracellular matrix (ECM) components during human retinal development is not fully understood. In this study, expression of key ECM components (Collagen IV, Fibronectin, Brevican, Versican, IMPG1 and IMPG2) was investigated during human retinal ontogenesis. Collagen IV and Fibronectin were expressed in Bruch's membrane; whereas Brevican, Versican, IMPG1 & IMPG2 in the developing interphotoreceptor matrix (IPM). Retinal organoids were successfully generated from pluripotent stem cells. The expression of ECM components was examined in the retinal organoids and found to recapitulate human retinal development in vivo. Using functional blocking experiments, we were able to highlight an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation.

EVALUATION OF FULL-FIELD ELECTRORETINOGRAM REDUCTIONS AFTER OCRIPLASMIN TREATMENT: Results of the OASIS Trial ERG Substudy

The Ocriplasmin for Treatment for Symptomatic Vitreomacular Adhesion Including Macular Hole (OASIS) trial electroretinogram substudy assessed a possible association between vitreomacular adhesion and best-corrected visual acuity with changes to full-field electroretinograms as part of a prospective, randomized, double-masked, sham-controlled clinical trial studying the efficacy and safety of ocriplasmin for the treatment of symptomatic vitreomacular adhesion.

Purpose:

To explore a possible association between full-field electroretinograms with vitreomacular adhesion resolution and best-corrected visual acuity as part of the prospective, randomized, double-masked, sham-controlled Ocriplasmin for Treatment for Symptomatic Vitreomacular Adhesion Including Macular Hole (OASIS) trial studying ocriplasmin.

Methods:

The ERG substudy enrolled 62 of 220 OASIS subjects (randomized 2:1) and analyzed full-field electroretinograms and their association with both vitreomacular adhesion resolution and best-corrected visual acuity from baseline through Month 24. Electroretinogram reductions were defined as acute full-field electroretinogram reductions in amplitude of ≥40% from baseline occurring at postinjection Day 7 or Day 28.

Results:

In the ocriplasmin group, 16/40 (40%) subjects developed ERG reductions, compared to 1/21 (4.8%) in the sham group; 13/16 (81.3%) and 1/1 (100%) resolved by study end, respectively. A total of 11/16 (68.8%) ocriplasmin-treated subjects with ERG reductions achieved vitreomacular adhesion resolution, compared to those without (9/24, 37.5%). The ocriplasmin-treated subjects with ERG reductions also gained more letters on average (11.3 vs. 9.3 letters) from baseline and had a difference of 6.7 letters in mean best-corrected visual acuity by study end compared to those without ERG reductions.

Conclusion:

Ocriplasmin-treated subjects with ERG reductions had a higher rate of vitreomacular adhesion resolution and showed better visual improvement than their counterparts without ERG reductions or sham subjects by study end.

SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY FINDINGS AND VISUAL OUTCOME AFTER TREATMENT FOR VITREOMACULAR TRACTION

PURPOSE

To evaluate the capacity of spectral domain optical coherence tomography macular findings to predict best-corrected visual acuity (BCVA) outcomes after treatment for symptomatic vitreomacular traction.

METHODS

This consecutive, retrospective study included 24 patients (29 eyes) who experienced vitreomacular traction release with pneumatic vitreolysis (n = 9), intravitreal ocriplasmin (n = 6), or pars plana vitrectomy (n = 14). Preoperative and postoperative spectral domain optical coherence tomography images were used to determine the cone outer segment tips (COST) line, inner segment/outer segment line, and other frequently used features. Correlations between optical coherence tomography findings and BCVA were determined using regression analyses.

RESULTS

Postoperative BCVA was correlated with length of the COST line and inner segment/outer segment line defects at 1, 3, 6, and 12 months postoperatively (P < 0.05) by simple linear regression analysis. However, multivariable regression analysis showed that only length of the COST line defect was significantly correlated with BCVA preoperatively and postoperatively (P < 0.05). Postoperative BCVA improvement at 12 months was significantly correlated with preoperative length of the COST line defect (P < 0.01).

CONCLUSION

Recovery of the COST line and inner segment/outer segment line defects as observed by spectral domain optical coherence tomography is positively correlated with visual acuity improvement after successful vitreomacular traction treatment. Best-corrected visual acuity improvement may be predicted using the length of the preoperative COST line defect.

Multimodal imaging of macular subretinal deposits following intravitreal ocriplasmin injection

Purpose

Ocriplasmin is effective in closing macular holes due to vitreomacular traction. We present a case of macular subretinal material deposition observed with spectral-domain optical coherence tomography (SD-OCT) and multimodal imaging, following successful closure of a macular hole following intravitreal ocriplasmin injection.

Observations

An 81-year-old male presented with decreased vision in the left eye due to a full-thickness macular hole secondary to vitreomacular traction. Ocriplasmin (Jetrea) was injected into the vitreous and hole closure was observed after one week. Macular subretinal material deposition developed along the outer surface of the resultant serous detachment on OCT one week post-injection. Fluorescein angiography demonstrated no expanding hyperfluorescence due to retinal or choroidal leak, or staining of the lesion. The material was mildly autofluorescent. The macular subretinal material complex spontaneously decreased with no significant effect on vision over 60 weeks.

Conclusions and importance

Macular subretinal material deposition has not previously been reported following intravitreal ocriplasmin injection. This material is likely composed of photoreceptor outer segments. It is important to recognize that macular subretinal deposits can occur following intravitreal ocriplasmin injection as it may cause diagnostic confusion and potentially influence the visual and anatomical outcomes following successful hole closure.

Assessment of Ocriplasmin Effects on the Vitreoretinal Compartment in Porcine and Human Model Systems

Ocriplasmin (Jetrea®) is a recombinant protease used to treat vitreomacular traction. To gain insight into vitreoretinal observations reported after ocriplasmin treatment, we have developed an in vivo porcine ocriplasmin-induced posterior vitreous detachment (PVD) model in which we investigated vitreoretinal tissues by optical coherence tomography, histology, and cytokine profiling. Eight weeks postinjection, ocriplasmin yielded PVD in 82% of eyes. Subretinal fluid (85%) and vitreous hyperreflective spots (45%) were resolved by week 3. Histological analysis of extracellular matrix (ECM) proteins such as laminin, fibronectin, and collagen IV indicated no retinal ocriplasmin-induced ECM distribution changes. Retinal morphology was unaffected in all eyes. Cytokine profiles of ocriplasmin-treated eyes were not different from vehicle. In cell-based electrical resistance assays, blood-retinal barrier permeability was altered by ocriplasmin concentrations of 6 μg/mL and higher, with all effects being nontoxic, cell-type specific, and reversible. Ocriplasmin was actively taken up by RPE and Müller cells, and our data suggest both lysosomal and transcellular clearance routes for ocriplasmin. In conclusion, transient hyperreflective spots and fluid in a porcine ocriplasmin-induced PVD model did not correlate with retinal ECM rearrangement nor inflammation. Reversible in vitro effects on blood-retinal barrier permeability provide grounds for a hypothesis on the mechanisms behind transient subretinal fluid observed in ocriplasmin-treated patients.

Assessment of intravitreal ocriplasmin treatment for vitreomacular traction in clinical practice

PURPOSE

To assess treatment effects following intravitreal injection of ocriplasmin for vitreomacular traction (VMT), with or without full-thickness macular hole (FTMH), in real-life setting.

METHODS

This is a monocentric, retrospective, consecutive series of 82 eyes from 82 patients who underwent ocriplasmin treatment between July 2013 and December 2016. We included 57 eyes with pure VMT, 17 eyes with small FTMHs, and eight eyes with medium FTMHs. Primary outcome measures were VMT release and MH closure rates. Secondary outcomes were visual acuity (VA), morphological changes, and subjective visual impairment after 1, 3, and 6 months and at last follow-up.

RESULTS

After a median follow-up of 10 months, VMT release was achieved by pharmacologic vitreolysis in 57% of all eyes, whereas the macular hole closure rate was 32%. In those presenting with five or more positive prognostic factors (PPF), eyes with pure VMT showed nonsurgical traction release in 88%, and FTMHs were released in 93%, with a closure rate of 20%. Small FTMHs closed in 41% and medium FTMHs in 13%. The mean change in VA (LogMAR) was -0.07 ± 0.24 (median - 0.10) in all eyes. Subretinal fluid accumulation and ellipsoid zone changes were seen in 31% and 37% of all eyes, respectively. They were more frequent in eyes with traction release, but were self-limited.

CONCLUSIONS

In a real-life setting, release of VMT by ocriplasmin injection can be achieved in the majority of eyes, relying on a strict patient selection. Closure of FTMHs rather correlates with hole diameter than with presence of PPF, and remains a rare finding in medium FTMHs.

WIDESPREAD MACULAR NEUROSENSORY DETACHMENT AFTER OCRIPLASMIN INTRAVITREAL INJECTION

PURPOSE

To present the case of a patient with vitreomacular traction who experienced immediate severe acute complications after ocriplasmin intravitreal injection.

METHODS

Case report.

RESULTS

A 61-year-old woman with vitreomacular traction underwent ocriplasmin treatment. Within 24 hours after injection, she noticed severe reduction in visual acuity. Spectral domain optical coherence tomography revealed release of vitreous traction, together with widespread subretinal fluid and decreased reflectivity in the outer retina. Ten weeks after treatment, visual acuity improved, although below pretreatment levels, with partial reduction in subretinal fluid.

CONCLUSION

Intravitreal ocriplasmin can produce acute visual acuity changes with widespread subretinal fluid and outer retinal ellipsoid zone hyporeflectivity on spectral domain optical coherence tomography. The overall acute and long-term safety profile of ocriplasmin remains unknown.

ELLIPSOID ZONE MAPPING AND OUTER RETINAL CHARACTERIZATION AFTER INTRAVITREAL OCRIPLASMIN

PURPOSE

To assess outer retinal architectural alterations after intravitreal ocriplasmin with a novel automated ellipsoid zone (EZ) mapping algorithm.

METHODS

A single-center, retrospective, consecutive case series of image analysis was performed. Quantitative assessment of EZ status imaged with spectral-domain optical coherence tomography was performed before and after single intravitreal injection of 0.125 mg of ocriplasmin (Jetrea, Thrombogenics). A novel EZ mapping algorithm was used to assess the EZ retinal pigment epithelium (RPE) central area, EZ-RPE macular volume, and en face EZ integrity based on the percentage of sampling areas with 20 μm or greater EZ-RPE thickness. Longitudinal assessment of these changes with custom optical coherence tomography reading software was completed. Clinical characteristics and outcomes were compared with these retinal changes.

RESULTS

Nineteen eyes were included in this study. The retinal volume between EZ and RPE was significantly reduced at 1 week after ocriplasmin (P = 0.0036). Seven of 19 patients (36.8%) complained of color abnormalities or brightness reduction after injection. All of these seven patients had increased subretinal fluid after ocriplasmin and EZ attenuation. The EZ-RPE volume was reduced at 1 week (P = 0.0036), 1 month (P = 0.015) after ocriplasmin, and restored by 3 months. The area with EZ-RPE thickness below 20 μm was increased at 1 week (P = 0.046) after ocriplasmin and recovered with time.

CONCLUSION

Mapping of EZ is feasible to assess EZ-RPE volume and overall EZ integrity with en face thickness mapping. Alterations in EZ occur in a significant proportion of eyes after ocriplasmin therapy. The EZ-RPE volume and the EZ-RPE central foveal area typically recover to baseline by 3 months. This effect appears to be panretinal and associated with subjective symptoms.

The Portuguese Experience with Ocriplasmin in Clinical Practice

AIM

Evaluate the real-life experience with ocriplasmin on vitreomacular traction (VMT) release and full-thickness macular hole (FTMH) closure in Portugal.

METHODS

Multicentric, retrospective study of 83 eyes of 78 patients who were treated with intravitreal ocriplasmin for VMT with and without FTMH. Primary outcomes were VMT release and FTMH closure. Secondary outcomes included visual acuity changes and structural features on spectral-domain ocular coherence tomography.

RESULTS

VMT resolved in 47 of the 83 eyes (56.6%) and 6 of the 12 FTMH were closed (50.0%). Mean best-corrected visual acuity (BCVA) improved from 65.1 at baseline to 70.8 ETDRS letters at the end of follow-up (p < 0.0001) with a mean follow-up of 138.8 days. Improvement in BCVA was significantly better in eyes with VMT release (p = 0.021). Approximately 73% of patients had normal ellipsoid zone integrity at the end of follow-up, 87% had no neurosensorial detachment and 40% had no intra- or subretinal fluid.

CONCLUSION

VMT release and FTMH closure were achieved in more than half of the treated eyes and were correlated with significant BCVA improvements and favorable baseline characteristics. In fact, if a careful patient selection is carried out, VMT resolution with ocriplasmin can be optimized, tailoring the best approach to each patient.

Biomechanical Properties of the Internal Limiting Membrane after Intravitreal Ocriplasmin Treatment

Purpose: To assess the stiffness of the human internal limiting membrane (ILM) and evaluate potential changes of mechanical properties following intravitreal ocriplasmin injection for vitreomacular traction. Methods: This is an interventional comparative case series of 12 surgically excised ILM specimens consecutively obtained from 9 eyes of 9 patients after unsuccessful pharmacologic vitreolysis with ocriplasmin. During the same time period, 16 specimens from 13 other eyes without ocriplasmin treatment were harvested during vitrectomy and served as controls. All patients presented with macular holes or vitreomacular traction and underwent vitrectomy with ILM peeling either with or without brilliant blue (BB) staining. All specimens were analyzed using atomic force microscopy with scan regions of 25 × 25 μm. In all specimens, both the retinal side and vitreal side of the ILM were analyzed. Results: Atomic force microscopy revealed no significant differences in elasticity of ILM specimens removed from eyes with or without ocriplasmin treatment. Undulated areas of the retinal side presented stiffer than the vitreal side of the ILM. Topographical mapping of both the vitreal and retinal side of the ILM showed no apparent alteration of the morphology in ocriplasmin-treated eyes compared to untreated eyes. Staining with BB resulted in an increase of tissue stiffness. Conclusions: Intravitreal injection of ocriplasmin does not change biomechanical properties of the human ILM. There is no evidence of a potential enzymatic effect of ocriplasmin interfering with the stiffness of this basement membrane.

Severe acute vision loss, dyschromatopsia, and changes in the ellipsoid zone on sd-oct associated with intravitreal ocriplasmin injection

PURPOSE

To present the long-term follow-up of a patient injected with intravitreal ocriplasmin who experienced severe acute post-intravitreal ocriplasmin complications.

METHODS

Case report.

RESULTS

A 68-year-old man with vitreomacular traction was treated with intravitreal ocriplasmin. He experienced dyschromatopsia, severe acute visual acuity, and field loss 4 hours after the injection. This was accompanied by decreased reflectivity on spectral domain optical coherence tomography in the ellipsoid zone of the outer retina. These changes were transient, and 3 years after the injection, the patient is asymptomatic and no outer reflectivity changes are noted on his spectral domain optical coherence tomography images.

CONCLUSION

Acute visual changes and spectral domain optical coherence tomography hyporeflectivity in the ellipsoid zone after intravitreal ocriplasmin can occur in some individuals, but in this case, these changes were reversible, and there have been no long-term implications.

Complications of intravitreal ocriplasmin for vitreomacular traction and macular hole: a prospective spectral-domain optical coherence tomography study

OBJECTIVE

The purpose of this study was to evaluate the safety of intravitreal ocriplasmin prospectively, reporting potential complications in patients with vitreomacular traction (VMT) alone or associated with macular hole (MH).

MATERIALS AND METHODS

Participants in this prospective, multicenter study, were 24 patients with VMT (17 with VMT alone and seven with MH combined with VMT). All patients were treated with a single ocriplasmin injection and followed-up prospectively at baseline, day 7, 28 and the last examination of the follow-up for each patient (mean ± SD: 64.2 ± 24.4 d, range: 40-145 d). Best-corrected visual acuity (BCVA) was assessed, and spectral-domain optical coherence tomography was performed at each visit while the percentage of resolution of VMT and the association with various potential adverse events were recorded and analyzed.

RESULTS

66.7% of patients presented VMT release at the end of the follow-up, while 28.6% exhibited MH closure. Severe adverse events, such as enlargement of preexisting MH and formation of lamellar MH, were observed in one and four cases, respectively and remained till the end of the follow-up. Moderate adverse events, such as ellipsoid zone disruption and subretinal fluid development, became evident seven days after injection, in four cases. Formation of cystoid macular edema (CME), not evident at baseline, was noticed in three cases at day 28 after injection. Mild adverse events, like vitreous floaters, photopsias, eye pain and foreign body sensation, were noticed at day 7 and resolved till the end of the follow-up.

CONCLUSIONS

Mild and moderate adverse events occurred mainly during the first week of the follow-up, while severe adverse events, such as the lamellar MH formation and CME at day 28 post injection were seen.

Acute loss of vision after an intravitreal injection ocriplasmin: a functional evolutionary study for 1-year follow-up

INTRODUCTION

Ocriplasmin is a human plasmin fragment indicated for vitreomacular traction treatment. With its increasing use, several reported cases have suggested possible toxicity to the retina.

CASE

We describe a case of a 55-year-old woman with symptomatic vitreomacular traction and a macular hole in the right eye who showed an acute decrease in visual acuity after an intravitreal ocriplasmin injection. Spectral-domain optical coherence tomography showed an alteration in the ellipsoid layer. Significant retinal vessel constriction was observed by angiography. The visual acuity improved to 20/100, and the electroretinogram progressively improved after the 1-year follow-up and following pars plana vitrectomy.

CONCLUSIONS

A decrease in visual acuity and an enlargement of the macular hole were observed while studying this patient. This study shows the recovery of adverse effects caused by intravitreal injection of ocriplasmin for 1-year follow-up.

Pathology of Internal Limiting Membrane Specimens Following Intravitreal Injection of Ocriplasmin

PURPOSE

To describe ultrastructure and immunocytochemistry of internal limiting membrane peelings after unsuccessful treatment with ocriplasmin, to compare with untreated eyes, and to correlate with clinical imaging data.

DESIGN

Interventional comparative case series.

METHODS

Internal limiting membrane specimens were removed from 10 eyes with small macular holes and vitreomacular traction during vitrectomy after intravitreal ocriplasmin injection without release of traction or closure of macular holes during follow-up. Based on optical coherence tomography analysis, specimens from 10 other eyes without ocriplasmin treatment served as controls. All specimens were processed as flat mounts for phase-contrast microscopy followed by immunolabeling for fluorescence microscopy and embedding in epoxy resin with serial sectioning for transmission electron microscopy.

RESULTS

Despite the absence of contractive epiretinal membranes on optical coherence tomography, we found epiretinal cells and vitreous collagen fibrils on the internal limiting membrane in specimens removed from eyes with and without previous pharmacologic vitreolysis. Immunolabeling revealed glial cells and hyalocytes in macular holes, whereas myofibroblasts were predominant in vitreomacular traction. There was no apparent damage of the vitreoretinal interface after unsuccessful pharmacologic vitreolysis compared to untreated controls.

CONCLUSIONS

Epiretinal cell proliferation and vitreous collagen fibrils with close adhesions to the internal limiting membrane are not always detectable by optical coherence tomography or may not have been recognized. Since they are associated with unsuccessful ocriplasmin treatment, presence and topography of epiretinal cells and vitreous collagen remnants on the internal limiting membrane should be further elucidated in order to refine criteria and indications for case selection in pharmacologic vitreolysis.

Glia-neuron interactions in the mammalian retina

The mammalian retina provides an excellent opportunity to study glia-neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K(+) uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.

Efficacy of intravitreal ocriplasmin for treatment of vitreomacular adhesion: subgroup analyses from two randomized trials

PURPOSE

To evaluate the efficacy of a single intravitreal injection of ocriplasmin 125 μg across relevant subpopulations of patients with symptomatic vitreomacular adhesion (VMA)/vitreomacular traction (VMT), including when associated with macular hole.

DESIGN

Two multicenter, randomized, placebo-controlled, double-masked, 6-month studies.

PARTICIPANTS

A total of 652 randomized patients (464 receiving ocriplasmin; 188 receiving placebo).

METHODS

A single intravitreal injection of ocriplasmin 125 μg or placebo in the study eye.

MAIN OUTCOME MEASURES

Prespecified subgroup analyses were conducted to evaluate the effects on the proportion of patients with nonsurgical resolution of focal VMA at day 28, nonsurgical full-thickness macular hole (FTMH) closure at month 6, and categoric improvement in best-corrected visual acuity (BCVA) at month 6.

RESULTS

Resolution of VMA at day 28 was achieved more often in younger patients (<65 years), eyes without epiretinal membrane, eyes with FTMH, phakic eyes, and eyes with a focal VMA ≤ 1500 μm. Eyes with FTMH width ≤ 250 μm were more likely to achieve nonsurgical FTMH closure. Categoric ≥ 2-line and ≥ 3-line improvement in BCVA occurred more often in younger patients (<65 years) and in patients with a lower baseline BCVA (<65 letters). Treatment differences in favor of ocriplasmin were generally observed across each subgroup of subpopulations studied.

CONCLUSIONS

Subgroup analyses confirmed the positive effect of ocriplasmin across relevant subpopulations.

Retinal breaks due to intravitreal ocriplasmin

Ocriplasmin represents a new treatment option for numerous vitreoretinopathies involving an abnormal vitreomacular interface. While the drug may circumvent the traditional risks of surgical treatment, pharmacologic vitreolysis is not devoid of risk itself. This report presents two cases, one of vitreomacular traction syndrome and the other of a full-thickness macular hole, both of which were treated with an intravitreal injection of ocriplasmin. Notably, in both cases, vitreomacular traction of the macula appears to have been alleviated; however, failure to completely relieve vitreoretinal traction from the peripheral retina generated retinal breaks with one patient eventually developing a macula-involving retinal detachment. Thus, even in instances of ‘successful’ pharmacologic treatment of vitreomacular traction, continued follow-up evaluation is essential.

An endoscopic overview of the anterior vitreous base in retinal detachment and anterior proliferative vitreoretinopathy

PURPOSE

Anterior proliferative vitreoretinopathy (PVR) is an important cause of persistent or recurrent retinal detachment (RD). Endoscopy provides 360° panoramic viewing of the vitreous cavity and high-magnification viewing of the anterior vitreous base (AVB). This study describes the 'in vivo' anatomy and pathoanatomy of the AVB using an ocular endoscope in RD and anterior PVR.

METHODS

An intraoperative analysis of over 2000 consecutive eyes undergoing vitrectomy for RD operated with endoscopy-assisted vitrectomy was performed. It was recorded in notes dictated during surgery and in standardized operative reports. Around 1500 surgical videotapes, with the exclusion of diabetic retinopathy and trauma, selected by reviewing the OR reports and notes were retrospectively reviewed.

RESULTS

Seven endoscopic criteria associated with anterior PVR complicating RD are described: 'en bloc' stiff anterior vitreous retraction, ciliary detachment, seeding of the AVB by abundant pigmented and/or white granulations, anterior tissue displacement, stiff 'wrinkling' at the vitreoretinal juncture, persistent shallow ciliary/RD under perfluorocarbon liquids and traction-related retinal surface haemorrhages. Causes responsible for failure of conventional vitrectomy for RD are highlighted. Findings in case of hypotony and cyclitic membranes are described.

CONCLUSIONS

Endoscopy is a significant adjunct to our understanding of the development of anterior loop traction by obviating the two constitutive parts of the AVB, anterior and posterior, their interconnections and their respective connections to the anterior segment and to the retina. It provides a unique evaluation and thorough eradication of the anterior vitreous cortex as a scaffold for anterior PVR. It might be an adjunct to the prevention of anterior PVR.

Profile of ocriplasmin and its potential in the treatment of vitreomacular adhesion

The recent approval by the US Food and Drug Administration of ocriplasmin for the treatment of symptomatic vitreomacular adhesion (VMA), often associated with vitreomacular traction (VMT) and macular hole (MH), has brought new attention to the field of pharmacologic vitreolysis. The need for an enzyme to split the vitreomacular interface, which is formed by a strong adhesive interaction between the posterior vitreous cortex and the internal limiting membrane, historically stems from pediatric eye surgery. This review summarizes the different anatomic classifications of posterior vitreous detachment or anomalous posterior vitreous detachment and puts these in the context of clinical pathologies commonly observed in clinical practice of the vitreoretinal specialist, such as MH, VMT, age-related macular degeneration, and diabetic macular edema. We revisit the outcome of the Phase II studies that indicated ocriplasmin was a safe and effective treatment for selected cases of symptomatic VMA and MH. Release of VMA at day 28 was achieved by 26.5% of patients in the ocriplasmin group versus 10.1% in the placebo group (P<0.001). Interestingly, for MHs, the numbers were more remarkable. Predictive factors for successful ocriplasmin treatment were identified for VMT (VMA diameter smaller than 1,500 μm) and MH (smaller than 250 μm). In comparison with the highly predictable outcome after vitrectomy, the general success rate of ocriplasmin not under clinical trial conditions has not fully met expectations and needs to be proven in real-world clinical settings. The ocriplasmin data will be compared in the future with observational data on spontaneous VMA release, will help retina specialists make more accurate predictions, and will improve outcome rates.

Ocriplasmin for symptomatic vitreomacular adhesion: an evidence-based review of its potential

Vitreomacular traction is a multicategory entity that may cause substantial visual loss due to the formation of a macular hole or traction-induced tissue distortion. The advent of optical coherent tomography (OCT) has demonstrated the anatomic features of persistent vitreomacular attachment (VMA) more definitively, including in many asymptomatic or minimally symptomatic patients. The indications for intervention are unclear, since it is not possible to predict which eyes might be likely to develop progressive visual loss. This has been especially important since for many years, the only treatment option involved surgical intervention (vitrectomy) to release the persistent VMA. Recently, a pharmacolytic agent, ocriplasmin, has become available after many years of development and investigation, and may offer a feasible alternative to surgery, or even a risk/benefit ratio sufficiently favorable to offer intervention at an earlier stage of VMA. Several studies, including a large, prospective clinical trial, have established the foundation of its rationale and efficacy, providing the basis of its approval. The role for ocriplasmin in clinical practice is in the process of being determined. This paper summarizes current knowledge and status of investigations regarding ocriplasmin-induced pharmacologic vitreolysis, and offers some evidence-based considerations for its use.

Idiopathic vitreomacular traction and macular hole: a comprehensive review of pathophysiology, diagnosis, and treatment

Posterior vitreous detachment (PVD) is a common phenomenon in the aging eye. However, this may be complicated by persistent symptomatic vitreomacular adhesions that exert tractional forces on the macula (vitreomacular traction; VMT). VMT itself may be associated with epiretinal membrane formation and the development of idiopathic macular holes (IMH). Such pathologies may cause visual disturbances, including metamorphopsia, photopsia, blurred vision, and decreased visual acuity, which impact an individual's quality of life. Technologies such as optical coherence tomography allow an increasingly more accurate visualisation of the macular anatomy, including quantification of macular hole characteristics, and this facilitates treatment decision-making. Pars plana vitrectomy remains the primary treatment option for many patients with VMT or IMH; for the latter, peeling of the inner limiting membrane (ILM) of the retina has shown improved outcomes when compared with no ILM peeling. The development of narrow-gauge transconjunctival vitrectomy systems has improved the rate of visual recovery following surgery. Ocriplasmin, by degrading laminin and fibronectin at the vitreoretinal interface, may allow induction of PVD in a non-invasive manner. Indeed, clinical studies have supported its use as an alternative to surgery in certain patient populations. However, further research is still needed with respect to greater understanding of the pathophysiology underlying the development of VMT and IMH.

Ocriplasmin for vitreoretinal diseases

Fibronectin and laminin are clinically relevant plasmin receptors in the eye. Located at the vitreoretinal interface, they are cleaved by ocriplasmin (Microplasmin, ThromboGenics, Iselin, NJ), a novel ophthalmic medication. A series of clinical trials to study ocriplasmin for the treatment of vitreoretinal diseases such as vitreomacular traction, macular hole, and exudative age-related macular degeneration are underway. The results are promising and may impact patient care.

Osteopontin and fibronectin levels are decreased in vitreous of autoimmune uveitis and retinal expression of both proteins indicates ECM re-modeling

Autoimmune uveitis is an intraocular inflammation that arises through autoreactive T-cells attacking the inner eye, eventually leading to blindness. However, the contributing molecular pathomechanisms within the affected tissues remain as yet elusive. The extracellular matrix (ECM) is a highly dynamic structure that varies tremendously and influences the encompassing tissue. In order to assess ECM re-modeling in autoimmune uveitis, we investigated the expression of ECM molecules fibronectin and osteopontin in vitreous and retina samples. This was carried out in the only spontaneous animal model for human autoimmue uveitis, namely equine recurrent uveitis (ERU) that resembles the human disease in clinical as well as in immunopathological aspects. ERU is a naturally occurring autoimmune disease in horses that develops frequently and has already proved its value to study disease-related pathomechanisms. Western blot analysis of fibronectin and osteopontin in healthy and uveitic vitreous revealed significant reduction of both proteins in uveitis. Immunohistochemical expression of fibronectin in healthy retinas was restricted to the inner limiting membrane abutting vimentin positive Müller cell endfeet, while in uveitic sections, a disintegration of the ILM was observed changing the fibronectin expression to a dispersed pattern extending toward the vitreous. Retinal expression of osteopontin in control tissue was found in a characteristic Müller cell pattern illustrated by co-localization with vimentin. In uveitic retinas, the immunoreactivity of osteopontin in gliotic Müller cells was almost absent. The ability of Müller cells to express fibronectin and osteopontin was additionally shown by immunocytochemistry of primary cultured equine Müller cells and the equine Müller cell line eqMC-7. In conclusion, severe ECM re-modeling in autoimmune uveitis reported here, might affect the adhesive function of fibronectin and thus the anchoring of Müller cell endfeet to the ILM. Furthermore, the absence of osteopontin in gliotic Müller cells might represent reduced neuroprotection, an osteopontin attribute that is intensively discussed.