Improved Outcomes with Heavy Silicone Oil in Complex Primary Retinal Detachment: A Large Multicenter Matched Cohort Study.

PURPOSE: To establish whether Densiron 68, a heavier-than-water endotamponade agent, is an effective alternative to conventional light silicone oil in primary rhegmatogenous retinal detachment (RD) surgery for eyes with inferior breaks in the detached retina and severe proliferative vitreoretinopathy (PVR). DESIGN: Cohort study of routinely collected data from the European Society of Retina Specialists and British and Eire Association of Vitreoretinal Surgeons vitreoretinal database between 2015 and 2022. PARTICIPANTS: All consecutive eyes that underwent primary rhegmatogenous RD surgery using Densiron 68 or light silicone oil as an internal tamponade agent. METHODS: To minimize confounding bias, we undertook 2:1 nearest-neighbor matching on inferior breaks, large inferior rhegmatogenous RDs, PVR, and, for visual analyses, baseline visual acuity (VA) between treatment groups. We fit regression models including prognostically relevant covariates, treatment-covariate interactions, and matching weights. We used g-computation with cluster-robust methods to estimate marginal effects. For nonlinear models, we calculated confidence intervals (CIs) using bias-corrected cluster bootstrapping with 9999 replications. MAIN OUTCOME MEASURES: Presence of a fully attached retina and VA at least 2 months after oil removal. RESULTS: Of 1061 eyes enrolled, 426 and 239 were included in our matched samples for anatomic and visual outcome analyses, respectively. The primary success rate was higher in the Densiron 68 group (113 of 142; 80%) compared with the light silicone oil group (180 of 284; 63%), with an adjusted odds ratio of 1.90 (95% CI, 1.63-2.23, P < 0.001). We also observed a significant improvement favoring Densiron 68 of -0.26 logarithm of the minimum angle of resolution (logMAR) in postoperative VA between the 2 groups (95% CI, -0.43 to -0.10, P = 0.002). The anatomic benefit of using Densiron 68 in eyes with inferior retinal breaks and large detachments was more pronounced among eyes with PVR grade C. We found no evidence of visual effect moderation by anatomic outcome or foveal attachment. CONCLUSIONS: Densiron achieved higher anatomic success rates and improved visual outcomes compared with conventional light silicone oil in eyes with inferior retinal pathology and severe PVR. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

[Biomechanics of diabetic vitreopapillary traction syndrome]. / Biomekhanika diabeticheskogo vitreopapillyarnogo traktsionnogo sindroma.

Diabetic vitreopapillary traction syndrome (VPT) is a variant of diabetic retinopathy (DR) that can lead to vision loss in advanced stages. This review reports on the biomechanics of the vitreous in the pathogenesis of proliferative DR, in particular diabetic VPT. The article analyzes and summarizes literature data, presents the views of different authors on this problem, and provides the results of Russian and foreign scientific research on this pathology. It is concluded that further research in this area can lead to a significant improvement in the results of therapy, timely diagnosis, and preservation of vision in patients with DR.

STRUCTURAL AND FUNCTIONAL MACULAR CHANGES AFTER RETINECTOMY FOR RETINAL DETACHMENT COMPLICATED BY PROLIFERATIVE VITREORETINOPATHY.

PURPOSE: To report anatomical and functional outcomes of nonprimary retinectomy for rhegmatogenous retinal detachment with Grade C proliferative vitreoretinopathy, to assess the structural and functional macular changes in successful eyes. METHODS: Retrospective single-center cohort study: one hundred-one consecutive retinectomies of 101 eyes affected by rhegmatogenous retinal detachment with C proliferative vitreoretinopathy between January 2014 and February 2020 were included. RESULTS: The mean preoperative best-corrected visual acuity (BCVA) was 1.48 ± 0.71 logarithm of the minimal angle of resolution (20/604 Snellen equivalent). The anatomical success rate was 78.2% after one retinectomy and 83.1% after two retinectomies. The final BCVA ≥ 20/200 was achieved in 29% of cases, 8% gained ≥ 20/80. The final mean postoperative BCVA of successes with oil in situ was 1.68 ± 0.59 (20/957 Snellen equivalent) compared with 1.07 ± 0.63 logarithm of the minimal angle of resolution (20/235 Snellen equivalent) of successes after oil removal (P = 0.00005). Postoperative macular optical coherence tomography was obtained from 60/84 successes (71%). The normal macular profile was found in 3%, whereas majority demonstrated exudative maculopathy (51.5%), macular atrophy (22%), tractional maculopathy (21.5%), and macular disciform scar (2%). Bivariate linear relationship between final central foveal thickness and BCVA was statistically significant (P = 0.000013). CONCLUSION: Satisfactory anatomical and functional outcome is possible after retinectomy for C proliferative vitreoretinopathy. Positive prognostic factors include the removal of oil without redetachment, normal macular status, and lower central foveal thickness. The functional outcome was influenced by macular changes, as final BCVA and central foveal thickness correlated.

PHACOVITRECTOMY FOR PRIMARY RHEGMATOGENOUS RETINAL DETACHMENT REPAIR: A Retrospective Review.

PURPOSE: To analyze the single surgery success rate and anterior segment complications related to phacoemulsification and intraocular lens implantation in a series of patients undergoing phacovitrectomy for all types of primary rhegmatogenous retinal detachment. METHODS: We performed a retrospective interventional case series on 302 eyes undergoing phacovitrectomy for primary rhegmatogenous retinal detachment repair between November 1, 2016, and February 2, 2019, in Edmonton, Canada. Primary outcomes included single surgery retinal reattachment rate and anterior segment complications. Secondary outcomes included the effects of proliferative vitreoretinopathy and macula and/or peripheral internal limiting membrane peeling on the rate of surgical success. RESULTS: The single surgery success rate of phacovitrectomy for all types of primary rhegmatogenous retinal detachment was 85.1%. The presence of proliferative vitreoretinopathy was associated with lower surgical success (odds ratio, 0.33; P = 0.01). Macular internal limiting membrane peeling was associated with higher surgical success (odds ratio, 2.4; P = 0.05). Anterior segment complications included posterior capsular opacification (28.8%), posterior synechiae (10.9%), and posterior capsular rupture (2.3%). CONCLUSION: Phacovitrectomy is a safe and effective treatment option for the primary repair of rhegmatogenous retinal detachments. This study provides evidence to support the safe incorporation of phacoemulsification and intraocular lens implantation with retinal surgery.

Suppression of connexin 43 phosphorylation promotes astrocyte survival and vascular regeneration in proliferative retinopathy.

Degeneration of retinal astrocytes precedes hypoxia-driven pathologic neovascularization and vascular leakage in ischemic retinopathies. However, the molecular events that underlie astrocyte loss remain unclear. Astrocytes abundantly express connexin 43 (Cx43), a transmembrane protein that forms gap junction (GJ) channels and hemichannels. Cx channels can transfer toxic signals from dying cells to healthy neighbors under pathologic conditions. Here we show that Cx43 plays a critical role in astrocyte apoptosis and the resulting preretinal neovascularization in a mouse model of oxygen-induced retinopathy. Opening of Cx43 hemichannels was not observed following hypoxia. In contrast, GJ coupling between astrocytes increased, which could lead to amplification of injury. Accordingly, conditional deletion of Cx43 maintained a higher density of astrocytes in the hypoxic retina. We also identify a role for Cx43 phosphorylation in mediating these processes. Increased coupling in response to hypoxia is due to phosphorylation of Cx43 by casein kinase 1δ (CK1δ). Suppression of this phosphorylation using an inhibitor of CK1δ or in site-specific phosphorylation-deficient mice similarly protected astrocytes from hypoxic damage. Rescue of astrocytes led to restoration of a functional retinal vasculature and lowered the hypoxic burden, thereby curtailing neovascularization and neuroretinal dysfunction. We also find that absence of astrocytic Cx43 does not affect developmental angiogenesis or neuronal function in normoxic retinas. Our in vivo work directly links phosphorylation of Cx43 to astrocytic coupling and apoptosis and ultimately to vascular regeneration in retinal ischemia. This study reveals that targeting Cx43 phosphorylation in astrocytes is a potential direction for the treatment of proliferative retinopathies.

COMPARISON BETWEEN RELEASABLE SCLERAL BUCKLING AND VITRECTOMY IN PATIENTS WITH PHAKIC PRIMARY RHEGMATOGENOUS RETINAL DETACHMENT.

PURPOSE: To compare the efficiency of releasable scleral buckling (RSB) and pars plana vitrectomy (PPV) in the treatment of phakic patients with primary rhegmatogenous retinal detachment. METHODS: The current study was a prospective randomized clinical trial. One hundred and ten eyes from 110 patients with primary rhegmatogenous retinal detachment and proliferative vitreoretinopathy of Grade B or less were included in this study. The patients were randomly allocated into an RSB group and a PPV group. The functional and anatomical success was compared between groups. RESULTS: The primary anatomical success rate (PPV 41/43 [95.35%] and RSB 38/41 [92.68%]) and final anatomical success rate (PPV and RSB 100%) showed a nonsignificant difference. The best-corrected visual acuity, intraocular pressure, and complications were not different between the groups. However, the incidence of cataract progression was higher in the PPV group (26 of 43 [60.47%]) than in the RSB group (4 of 41 [9.76%]) at the 12-month follow-up. The subfoveal choroidal thickness increased significantly in the RSB group 3 months after surgery, but no longer differed at the postoperative 6-month and 12-month follow-ups. The axial length had increased significantly 1 month after surgery, but the difference was no longer significant at 3 months, 6 months, and 12 months. CONCLUSION: The RSB and PPV procedures have the same effects on the functional and anatomical success for patients with phakic primary rhegmatogenous retinal detachment. Nevertheless, based on the few cases of intraocular complications and cataract progression, we believe that the RSB technique should be preferentially recommended.

Inactive Cas9 blocks vitreous-induced expression of Mdm2 and proliferation and survival of retinal pigment epithelial cells.

Mouse double minute (MDM)2 single nucleotide polymorphism (SNP) 309G allele in the second promoter of MDM2 enhances vitreous-induced expression of Mdm2 and degradation of the tumor suppressor protein p53. This MDM2SNP309G contributes to certain cancer development and experimental proliferative vitreoretinopathy. The goal of this study is to discover a novel strategy to only block vitreous-induced expression of Mdm2 for preventing vitreous-induced cell proliferation and survival and thus find a potential novel strategy to treat proliferation-related diseases. We created two mutations (D10A and H840A) in Streptococcus pyogenes (Sp)Cas9 within the nuclease domains (RuvC1 and HNH, respectively) to render this SpCas9 nuclease dead named as dCas9 in a lentiCRISPR v2 vector. Then an MDM2-sgRNA targeting the second promoter of human MDM2 gene was cloned into this vector for producing lentivirus to infect human retinal pigment epithelial (RPE) cells with, which carry a heterozygous genotype of MDM2SNP309 T/G. lacZ-sgRNA was used as a control. As a result, we discovered that vitreous from experimental rabbits induced a 1.9 ±â€¯0.2 fold increase in Mdm2 and a 2.0 ±â€¯0.2 fold decrease in p53 in the RPE cells with dCas9/lacZ-sgRNA compared to those with dCas9/MDM2-sgRNA, suggesting that dCas9 under the guidance of the MDM2-sgRNA prevented RV-stimulated increase in Mdm2. In addition, we found that the rabbit vitreous significantly enhanced cell proliferation (1.5 ±â€¯0.2 fold), survival against apoptosis (2.2 ±â€¯0.2 fold), migration (10 ±â€¯1.5%) and contraction (112.7 ±â€¯14.1 mm2) of the cells with dCas9/lacZ-sgRNA compared with those with dCas9/MDM2-sgRNA. These results indicated that application of the dCas9 targeted to the P2 of MDM2 is a potential therapeutic approach to diseases due to the P2-driven aberrant expression of Mdm2 - such as proliferative vitreoretinopathy.

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

PURPOSE: To determine predictive factors of proliferative vitreoretinopathy (PVR) formation after uncomplicated primary retinal detachment repair. METHODS: Retrospective, single-center, case-control study of 74 consecutive patients with (37 eyes) and without (37 eyes) PVR formation after undergoing uncomplicated primary surgery for retinal detachment repair. Logistic regression was used to assess factors associated with PVR formation. RESULTS: Retinal detachment involving the macula was 4.2 times (adjusted odds ratio; 95% confidence interval, 1.4-12.9; P = 0.0119) more likely to have PVR formation compared with those without. Patients who were current or former smokers were 3.6 times (adjusted odds ratio; 95% confidence interval, 1.1-11.7; P = 0.0352) more likely to have PVR formation compared with nonsmokers. Compared with 25-gauge (g) vitrectomy, larger gauge vitrectomy (20 g or 23 g) was 3.6 times (adjusted odds ratio; 95% confidence interval, 1.2-11.3; P = 0.0276) more likely to have PVR formation. Duration of retinal detachment symptoms, high myopia, lens status, lattice degeneration, location of retinal break, number of retinal breaks, and surgical technique (e.g., scleral buckle with or without vitrectomy versus vitrectomy alone) were not found to be predictive of PVR formation. CONCLUSION: Cigarette smoking and macular involvement are significant risk factors predictive of PVR formation after uncomplicated primary retinal detachment repair.

Intraocular Foreign Body Trauma in Operation Iraqi Freedom and Operation Enduring Freedom: 2001 to 2011.

PURPOSE: We update the incidence of intraocular foreign bodies (IOFB) in soldiers admitted to Walter Reed Army Medical Center from 2001 to 2011 after sustaining combat injuries in Operation Iraqi Freedom and Operation Enduring Freedom. DESIGN: This consecutive retrospective case series included 890 eyes of 652 patients. METHODS: Data were collected in the Walter Reed Ocular Trauma Database. Inclusion criteria were any American soldier or Department of Defense civilian with an IOFB injured in Operation Iraqi Freedom/Operation Enduring Freedom. Closed globe injuries with orbital foreign bodies, injury outside of a combat zone, or non-Department of Defense civilian trauma were the exclusion criteria. MAIN OUTCOME MEASURES: Primary outcome measures were final visual outcome and the number, size, and location of IOFBs. Secondary outcome measures included surgical procedures, use of eye protection, associated complications, source of injury and Ocular Trauma Score. RESULTS: There were 890 eye injuries in 652 patients evacuated to Walter Reed Army Medical Center between 2001 and 2011. IOFBs were found in 166 eyes of 149 patients (18.6%; 95% confidence interval [CI], 16.2%-21.3%). Most patients had a single IOFB (80.7%). An IOFB was positively associated with Ocular Trauma Score grade 1 or 2 (0-65) injuries (odds ratio [OR], 1.58; 95% CI, 1.07-2.38; P = 0.01). There were 130 eyes (78.33%) that had recorded time from initial visual acuity to final visual acuity and it ranged from 8 to 2421 days (mean, 433.24 days). Thirty-eight (25.16%; 95% CI, 18.89%-32.67%) eyes had no change in visual acuity, 98 (64.90%; 95% CI, 57.00%-72.07%) had improved visual acuity, and 15 (9.93%; 95% CI, 6.01%-15.84%) had decreased visual acuity. IOFB was not found to predict final visual acuity of <20/200 in multivariate analysis when other injury features were known (P = 0.1). Pars plana vitrectomy was completed on 124 eyes (74.70%). Removal of IOFB was performed in 118 eyes (71.08%; average of 31.67 days after initial injury) with a delayed procedure occurring after primary closure and antibiotics owing to a lack of surgical capacity in Iraq and Afghanistan. Retinal detachment occurred in 48 eyes (28.92%) and proliferative vitreoretinopathy in 44 eyes (26.5%). CONCLUSIONS: IOFBs occur frequently in combat ocular trauma and are significantly associated with more severe injuries. However, IOFBs were not found to be a significant risk factor for visual acuity of <20/200.

A clinical analysis of vitrectomy for severe vitreoretinopathy in patients with chronic renal.

BACKGROUND: The recent advancement in the management of chronic renal failure (CRF) has significantly increased the longevity of the patients, which increase the incidence of severe vitreoretinopathy. The vitrectomy is highly risky in this particular group of patients due to their systemic comorbidity. The timing surgical intervention is usually delayed because of the systemic conditions. This study is to evaluate the safety and effectiveness of 25-guage vitrectomy for severe vitreoretinopathy in the CRF patients. METHODS: In this retrospective study, 16 eyes of 16 CRF patients with severe vitreoretinopathy were undergone 25-guage vitrectomy in the department of Ophthalmology of the Second Hospital of Tianjin Medical University from February 2015 to April 2017. The visual outcome, complications and perioperative medical management were documented and analyzed. RESULTS: The best-corrected visual acuity(BCVA)of fourteen eyes were lower than 20/200 preoperatively. Surgery duration ranged from 28 to 72 min, with a mean of 48.4 ± 13.6 min. During the surgery, 12 eyes were diagnosed with DR, while two them were complicated with tractional retinal detachment and one with branch retinal vein occlusion. Three eyes were diagnosed with branch retinal vein occlusion, and one eye was diagnosed with hypertensive retinopathy. Postoperative BCVA of six eyes ≥20/40, seven eyes ≥20/200, and three eyes < 20/200. BCVA of eight eyes improved more than three lines, three eyes improved two lines, and four eyes improved one line. BCVA decreased from hand movement to light perception in one patient who developed neovascular glaucoma two weeks after surgery. CONCLUSION: In chronic renal failure patients with severe vitreoretinopathy, the well-planned minimally invasive vitrectomy is effective and safe. Additionally, careful management of the perioperative systemic conditions is important to improve the visual acuity and quality of life as well.

Plumbagin induces RPE cell cycle arrest and apoptosis via p38 MARK and PI3K/AKT/mTOR signaling pathways in PVR.

BACKGROUND: This study aimed to explore the effects of plumbagin (PLB) on ARPE-19 cells and underlying mechanism. METHODS: Cultured ARPE-19 cells were treated with various concentrations (0, 5, 15, and 25 µM) of PLB for 24 h or with 15 µM PLB for 12, 24 and 48 h. Then cell viability was evaluated by MTT assay and DAPI staining, while apoptosis and cell cycle progression of ARPE cells were assessed by flow cytometric analysis. Furthermore, the level of main regulatory proteins was examinated by Western boltting and the expression of relative mRNA was tested by Real-Time PCR. RESULTS: PLB exhibited potent inducing effects on cell cycle arrest at G2/M phase and apoptosis of ARPE cells via the modulation of Bcl-2 family regulators in a concentration- and time-dependent manner. PLB induced inhibition of phosphatidylinositol 3-kinase (PI3K) and p38 mitogen-activated protein kinase (p38 MAPK) signaling pathways contributing to the anti-proliferative activities in ARPE cells. CONCLUSIONS: This is the first report to show that PLB could inhibit the proliferation of RPE cells through down-regulation of modulatory signaling pathways. The results open new avenues for the use of PLB in prevention and treatment of proliferative vitreoretinopathy.

Slow-Release Dexamethasone in Proliferative Vitreoretinopathy: A Prospective, Randomized Controlled Clinical Trial.

PURPOSE: To test the hypothesis that adjunctive slow-release dexamethasone implant (Ozurdex; Allergan Inc, Irvine, CA) can improve the outcomes of vitreoretinal surgery for established proliferative vitreoretinopathy (PVR). DESIGN: A 2-year, single-center, prospective, participant- and surgeon-masked randomized controlled clinical trial (EudraCT No. 2011-004498-96). PARTICIPANTS: A total of 140 patients requiring vitrectomy surgery with silicone oil for retinal detachment with established PVR (Grade C) were randomized to standard (control) or study treatment (adjunct) in a 1:1 allocation ratio. METHODS: Intraoperatively, the adjunct group received an injection of 0.7 mg of slow-release dexamethasone (Ozurdex) at the time of (1) vitrectomy surgery and (2) silicone oil removal. The control group received standard care. MAIN OUTCOME MEASURES: Primary outcome measure was the proportion of patients with a stable retinal reattachment with removal of silicone oil without additional vitreoretinal surgical intervention at 6 months. Secondary outcomes included (1) final visual acuity (VA) (median and Early Treatment Diabetic Retinopathy Study [ETDRS] of 55 letters or better); (2) cystoid macular edema (CMO), foveal thickness, and macular volume; (3) development of overt PVR recurrence; (4) complete and posterior retinal reattachment; (5) tractional retinal detachment; (6) hypotony/increased intraocular pressure (IOP); (7) macula pucker/epiretinal membrane; (8) cataract; and (9) quality of life. RESULTS: All 140 patients were recruited within 25 months of study commencement; 138 patients had primary outcome data. Primary outcome assessment showed similar results in anatomic success between the 2 groups (49.3% vs. 46.3%, adjunct vs. control; odds ratio, 0.89; 95% confidence interval, 0.46-1.74; P = 0.733). Mean VA at 6 months was 38.3 ETDRS letters and 40.2 letters in the adjunct and control groups, respectively. Secondary anatomic outcomes (complete/posterior reattachment rates and PVR recurrence) were comparable between the 2 groups. At 6 months, fewer adjunct patients had CMO (42.7%) or a foveal thickness of >300 µm (47.6%) compared with controls (67.2% and 67.7%, respectively, P = 0.004, P = 0.023). CONCLUSIONS: A slow-release dexamethasone implant did not improve the primary anatomic success rate in eyes undergoing vitrectomy surgery with silicone oil for PVR. Further clinical trials are indicated to improve anatomic and visual outcomes in these eyes, but this study suggests that there is a greater reduction in CMO observed at 6 months in vitrectomized eyes treated with slow-release dexamethasone.

Role of epithelial-mesenchymal transition in proliferative vitreoretinopathy.

Proliferative vitreoretinopathy (PVR) is a potentially blinding fibrotic complication. It is caused by the formation and contraction of epiretinal membranes (ERMs) that ultimately lead to retinal folds and traction retinal detachments. While multiple cell types have been identified in ERMs, retinal pigment epithelial (RPE) cells have long been implicated as a key player in the pathophysiology of PVR. Clinical and experimental evidence has shown that RPE cells undergo epithelial-mesenchymal transition (EMT) to adopt a fibroblastic phenotype. Cell-cell adhesions maintained by adherens and tight junctions are important for the maintenance of RPE phenotype, and disruption of these junctional complexes results in EMT via activation of signaling pathways such as ß-catenin/Wnt and Hippo signaling, as well as transcription factors involving Zeb1, Snail, and ZONAB. Upon EMT, RPE cells can further differentiate into myofibroblasts in the presence of TGF-ß with cytoskeletal tension mediated by RhoGTPase. These fibroblasts and myofibroblasts derived from RPE cells can contribute to ERM formation by cell migration, proliferation and matrix modification, and play a key role in ERM contraction. It is not solely the proliferation of these cells that results in PVR but rather the contraction of these cells in the ERM.

Role of retinal pigment epithelial cell ß-catenin signaling in experimental proliferative vitreoretinopathy.

Proliferative vitreoretinopathy is caused by the contraction of fibrotic membranes on the epiretinal surface of the neurosensory retina, resulting in a traction retinal detachment and loss of visual acuity. Retinal pigment epithelial (RPE) cells play an important role in formation of such fibrotic, contractile membranes. We investigated the role of Wnt/ß-catenin signaling, a pathway implicated in several fibrotic diseases, in RPE cells in proliferative vitreoretinopathy. In vitro culture of swine RPE sheets resulted in nuclear translocation of ß-catenin in dedifferentiated RPE cells. FH535, a specific inhibitor of ß-catenin signaling, reduced the outgrowth of cultured RPE sheets and prevented dedifferentiated RPE cell proliferation and migration. It also inhibited formation of contractile membranes by dedifferentiated RPE cells on collagen I matrices. Expression and function of the ß-catenin signaling target connexin-43 were down-regulated by FH535, and functional blockade of connexins with carbenoxolone also prevented the in vitro formation of fibrotic, contractile membranes. Intravitreal injection of FH535 in swine also inhibited formation of dense, contractile membranes on the epiretinal surface and prevented development of traction retinal detachment. These findings demonstrate that ß-catenin signaling is involved in formation of contractile membranes by dedifferentiated RPE cells and suggest that adjunctive treatment targeting this pathway could be useful in preventing proliferative vitreoretinopathy.

The roles of signaling pathways in epithelial-to-mesenchymal transition of PVR.

Proliferative vitreoretinopathy (PVR) is the major cause of failure in patients undergoing surgery for rhegmatogenous retinal detachment (RRD). Characterized by the formation of an abnormal contractile membrane within the eye, PVR can cause tractional retinal redetachment. Epithelial-to-mesenchymal transition (EMT), in which epithelial cells morphologically and phenotypically transdifferentiate into mesenchymal cells, is the major pathological process implicated in PVR. Among the various cell types involved in the process, retinal pigment epithelium cells are primary contributors although, after decades of research, the mechanisms underlying EMT have remained elusive. Recently, signaling pathways, some involving growth factors, have been demonstrated to contribute to EMT. In this article, we review research to date about the roles of such signaling, including including transforming growth factor-beta-, hepatocyte growth factor-, platelet-derived growth factor-, and Notch-, Wnt/ß-catenin-, and Hippo-signaling pathways, in the EMT of PVR.

Inferior retinotomy and silicone oil tamponade for recurrent inferior retinal detachment and grade C PVR in eyes previously treated with pars plana vitrectomy or scleral buckle.

BACKGROUND: One of the most challenging problems in vitro-retinal surgery is the recurrence of retinal detachment in the context of high-grade proliferative vitreoretinopathy (PVR). The aim of our retrospective study was to assess the surgical outcomes of pars plana vitrectomy, 180° inferior retinotomy and silicone oil tamponade combined with phacoemulsification and IOL implantation for recurrent inferior retinal detachment with grade C PVR in phakic eyes. The study was carried out at tertiary referral centre - University Hospital of Rome "Tor Vergata". METHODS: Retrospective analysis of 33 eyes affected by recurrent inferior retinal detachment and grade C PVR after primary encircle scleral buckling (SB group - 12 eyes), or pars plana vitrectomy (PPV group - 21 eyes). All patients subsequently underwent PPV and silicone oil tamponade at our Institution. The first outcome measure was retinal reattachment, and second outcomes were reoperation rates, best-corrected visual acuity (BCVA) and postoperative complications. RESULTS: All patients in the SB group and 19 (90%) patients of the PPV group achieved retinal reattachment. Final BCVA was better in the SB group (p = 0.045). Two eyes in the PPV group required a third vitrectomy with heavy silicone oil tamponade. Postoperative complications included silicone oil in a deep anterior chamber (3 eyes in each group), untreatable hypotony in 1 eye in the PPV group (that led to enucleation due to phthisis bulbi), and elevated intraocular pressure in 3 patients (2 eyes in the PPV group). CONCLUSIONS: Phacoemulsification with IOL implant, PPV with silicone oil tamponade associated with 180° inferior retinotomy may lead to better anatomical success in patients who have previously undergone SB procedure for inferior retinal detachment repair compared with eyes that underwent a primary PPV.

The Effects of Ozurdex® (Dexamethasone Intravitreal Implant) on Experimental Proliferative Vitreoretinopathy.

PURPOSE: To investigate a new sustained-release formulation of dexamethasone (Ozurdex®) for inhibiting proliferative vitreoretinopathy (PVR) and its effect on the expression of retinal glial reaction and inflammation in experimental PVR eyes. METHODS: We used 30 pigmented rabbits for this study. One week after gas compression, the eyes were injected with 5 × 10(4) retinal pigment epithelial cells into the vitreous cavity to induce PVR. Concurrently, one eye also received an intravitreal injection of Ozurdex; the other eye was used as a control. PVR was graded by indirect ophthalmoscopy on days 1, 3, 7, 14, 21, and 28. The expression of the retinal glial reaction and inflammation in experimental PVR eyes were evaluated by Western blot analysis. RESULTS: PVR severity increased gradually and peaked after 14 days, and no differences in PVR severity between the study and control groups were observed at any time point. The expression of glial fibrillary acid protein (GFAP) increased on days 7 and 14 in both the PVR control and study groups. While the use of Ozurdex in the study group showed less GFAP expression, this difference was not significant. The expression of tumor necrosis factor (TNF)-α and interleukin (IL)-6 significantly increased on days 7 and 14 in PVR control eyes. There was a significant difference in TNF-α between PVR control eyes and Ozurdex-treated eyes on days 7 (p < 0.001) and 14 (p = 0.019). Ozurdex in the study group showed lower IL-6 expression; however, this difference was not significant on days 7 (p = 0.063) and 14 (p = 0.052). CONCLUSIONS: The intravitreal injection of Ozurdex suppressed the expression of inflammatory markers; however, it did not mitigate the severity of experimental PVR in this animal model. © 2015 S. Karger AG, Basel.

[THE ROLE OF INFLAMMATION IN THE DEVELOPMENT OF PROLIFERATIVE VITREORETINOPATHY].

This paper focuses on the risk factors of primay and secondary proliferative vitreoretinopathy, modern views of pathophysiology of this disease, and the role of inflammation in its development. Special attention is given to the involvement of pigment epithelial cells, macrophages, hyalocytes, gliocytes, supporting fibers (Muller's cells), mediators of inflammation, such as cytokines, chemokines, and growth factors, with reference to their interaction in the processes of proliferation and development of retinal membranes.

The retinal pigment epithelium: an important player of retinal disorders and regeneration.

The retinal pigment epithelium (RPE) is a partner of the neural retina and is indispensable for vision. In humans, proliferation and transformation (cell-type switching) of RPE cells after a traumatic injury of the neural retina causes a retinal disorder leading to loss of vision. In contrast, in certain adult amphibians such as Xenopus laevis and the newt, a similar process in RPE cells leads to regeneration of the entire retina. In this review, on the basis of accumulating evidence in basic biology and medical sciences, similarities and differences between these RPE-mediated retinal disorders and regeneration in adult vertebrates are highlighted, providing a connection to future research that should be designed to establish clues for the treatment of pathogenesis caused by RPE while promoting RPE-mediated retinal regeneration in a patient's eyes.

Anatomical and visual outcomes after two-port pars plana vitrectomy reoperation under silicone oil for epimacular membrane or recurrent retinal detachment.

PURPOSE: To describe the anatomical and visual outcomes in a series of patients undergoing two-port pars plana vitrectomy reoperation under silicone oil for recurrent retinal detachment (RD) due to proliferative vitreoretinopathy or epimacular membrane (EMM) after RD repair. METHODS: This study is a prospective, consecutive, interventional case series of patients presenting with recurrent RD or EMM under silicone oil. Two-port 25-gauge pars plana vitrectomy reoperation without an infusion port was performed in all cases. RESULTS: Thirty-nine patients were included. Reoperation pathology included recurrent RD with proliferative vitreoretinopathy (n = 33) and EMM alone (n = 6). The mean number of previous retinal surgeries was 2.4 ± 1.1 (range, 1-5). The mean overall follow-up was 24 ± 3.7 months. The mean visual acuity change from baseline at final follow-up was an improvement of 0.74 ± 0.63. Macular reattachment was achieved in 29 of 33 patients with RD, and EMMs were successfully removed in all patients. CONCLUSION: Two-port pars plana vitrectomy reoperation is an efficacious method for repair of consecutive RD due to proliferative vitreoretinopathy or EMM in patients with previous RD repair with silicone oil. Significant visual improvement with a low complication rate may be achieved in patients with advanced proliferative vitreoretinopathy or EMM under silicone oil.