Visual outcome of 25 Gauge vitrectomy for acute post operative infectious endophthalmitis.

BACKGROUND: The correlation between the change in foveal thickness measured using optical coherence tomography (OCT) following surgery for infectious endophthalmitis and preoperative and postoperative visual acuity is uncertain, and there are few pertinent studies on this topic. OBJECTIVE: We explored the variations in macular thickness using OCT after emergency vitrectomy for post-cataract infectious endophthalmitis and the relationship between macular thickness with changes in visual function. METHODS: We included 10 cases of post-cataract infectious endophthalmitis. Each patient underwent 25-G vitrectomy. RESULTS: The infection in all 10 patients was under control and visual function improved. Postoperative vitreous humor culture was positive in 8 patients, including 7 cases of coagulase-negative Staphylococcus epidermidis and 1 case of Lactobacillus acidophilus. The average age of these 10 patients was 71.60 ± 8.71 years (P< 0.05, two-tailed). There was no significant correlation between time 2 (the time of onset after cataract surgery) and visual prognosis. The average time 1 (the time of the vitrification surgery caused by the onset of the disease) was 1.45 ± 0.76 days (P< 0.05, two-tailed). The postoperative 3dVA ranged from 0.20 to 3.00, with an average visual acuity of 1.87 ± 1.12, which was superior to the preoperative value (P< 0.01, two-tailed). The correlation between the post3dVA and post 1mVA was significant. The post 1mVA ranged from 0.05 to 2.20, with an average visual acuity of 0.94 ± 0.74 (P< 0.05, two-tailed). The correlation between post 1mVA and post3mVA was significant. Also, paired t-tests comparing preoperative and postoperative visual acuity revealed a significant correlation (P< 0.05, two-tailed). The post3mVA was 0-1.00 with an average visual acuity of 0.44 ± 0.41. The postoperative foveal thickness ranged from 176.00 to 514.00 µm, with an average thickness of 281.10 ± 113.12 µm. CONCLUSION: Emergency 25-G minimally invasive vitrectomy can improve visual acuity and decrease the reoperation rate for patients who have acquired post-cataract infectious endophthalmitis. There were significant correlations between age, disease onset to operation time, preoperative and postoperative visual acuity, and postoperative macular thickness.

microRNA-218 Inhibits Oxygen-induced Retinal Neovascularization via Reducing the Expression of Roundabout 1.

BACKGROUND: The mechanisms of pathological retinal neovascularization (RNV) remain unknown. Several microRNAs were reported to be involved in the process of RNV. Oxygen-induced retinopathy (OIR) is a useful model to investigate RNV. Our present work explored the expression and the role of microRNA-128 (miR-218) in oxygen-induced RNV. METHODS: OIR was used to establish RNV model. The expression level of miR-218 in the retina from OIR mice was assessed by quantitative real-time reverse transcriptase polymerase chain reaction. Fluorescein angiography was performed in retinae of OIR mice, and RNV was quantified by hematoxylin and eosin staining to evaluate the effect of pCDH-CMV-miR-218 intravitreal injection on RNV in OIR mice. Roundabout 1 (Robo1) expression was detected by Western blotting in mouse retinal vascular endothelial cells expressing a high or low level of miR-218 and retinal tissues from OIR mice. Cell migration was evaluated by scratch wound assay. RESULTS: In OIR mice, the expression level of miR-218 was significantly down-regulated (P = 0.006). Retinal Robo1 expression was significantly increased at both mRNA and protein levels (P = 0.001, 0.008; respectively). miR-218 intravitreal injection inhibited retinal angiogenesis in OIR mice, and the restoration of miR-218 in retina led to down-regulation of Robo1. CONCLUSIONS: Our experiments showed that restoration of miR-218 inhibited retinal angiogenesis via targeting Robo1. MiR-218 contributed to the inhibition of retinal angiogenesis and miR-218 might be a new therapeutic target for preventing RNV.

Change of Retinal Nerve Layer Thickness in Non-Arteritic Anterior Ischemic Optic Neuropathy Revealed by Fourier Domain Optical Coherence Tomography.

PURPOSE: To examine the changes of non-arteritic anterior ischemic optic neuropathy (NAION) by serial morphometry using Fourier domain optical coherence tomography (FD-OCT). MATERIALS AND METHODS: Retrospective study in patients with newly diagnosed NAION (n=33, all unilateral) and controls (n=75 unilateral NAION patients with full contralateral eye vision) who underwent FD-OCT of the optic disk, optic nerve head (ONH), and macula within 1 week of onset and again 1, 3, 6, and 12 months later. The patients showed no improvement in vision during follow-up. RESULTS: Within 1 week of onset, all NAION eyes exhibited severe ONH fiber crowding and peripapillary retinal nerve fiber layer (RNFL) edema. Four had subretinal fluid accumulation and 12 had posterior vitreous detachment (PVD) at the optic disc surface. Ganglion cell complex (GCC) and RNFL thicknesses were reduced at 1 and 3 months (p < 0.05), with no deterioration thereafter. Initial RNFL/GCC contraction magnitude in the superior hemisphere correlated with the severity of inferior visual field deficits. CONCLUSIONS: NAION progression is characterized by an initial phase of accelerated RNFL and GCC deterioration. These results reveal that the kinetic change of neural retina in NAION and may have implication on the time window for treatment of NAION. FD-OCT is useful in the evaluation of NAION.

Integrin ß1 subunit signaling is involved in the directed migration of human retinal pigment epithelial cells following electric field stimulation.

AIMS: Direct current electric fields (EFs) can induce directed cell migration in a wide variety of cells, and this has been proven to be of importance in wound healing. Here we observed the effects of EFs on cultured human retinal pigment epithelial (RPE) cells and explored the possible involvement of integrin ß1 subunit signaling in the process. METHODS: Cultured human RPE cells were exposed to an EF at 5 V/cm for 3 h. The rate and directionality of cell migration were quantified. The distribution of integrin ß1 subunit was measured by immunohistochemistry and the expression of integrin ß1 subunit and phosphorylated focal adhesion kinase (FAK) was determined by PCR and Western blotting. Experiments were performed in the presence or absence of anti-integrin ß1 subunit antibody. RESULTS: During exposure to an EF at 5 V/cm for 3 h, the separated human RPE cells and wounded RPE monolayer demonstrated a cathodal-directed migration. The distribution of integrin ß1 subunit in the cells was also polarized to the cathode, and the expression in mRNA and its protein level were obviously increased. Furthermore, exposure to EFs of 5 V/cm triggered the phosphorylation of FAK in human RPE cells. In contrast, blocking of integrin ß1 subunit suppressed the directed migration of RPE cells and reduced the activation of FAK in EFs. CONCLUSIONS: These findings indicate that EF exposure results in directed migration of the separated RPE cells and RPE monolayer. These effects may partially act through the activation of integrin ß1 subunit signaling.

New modified iris suture technique for pupillary dilation in aphakic eyes during vitreoretinal surgery.

To describe a modified simple iris suture for pupillary dilation technique during vitrectomy in cases with a miotic pupil. Four translimbal incisions were created with a sharp straight blade at 1:30, 10:30, 4:30, and 7:30 o'clock, respectively. The straight needle of 10-0 polypropylene suture and a Sinskey IOL hook was used to displace the pupillary margin toward the limbus. In 3 cases, four sutures caused a 6-mm to 9-mm square-shaped pupil, and the pupil was allowed to return to a smaller size at the end of the operation. It is simple and may reduce postoperative complications.

Electric fields contribute to directed migration of human retinal pigment epithelial cells via interaction between F-actin and beta1 integrin.

PURPOSE: To observe the effects of electric fields (EFs) on the migration of human retinal pigment epithelial (RPE) cells and to explore possible related mechanisms. METHODS: Cultured human RPE cells were exposed to EFs, and images of the cells were obtained at regular intervals to evaluate the cell migration and viability. Distribution of F-actin and beta1 integrin was measured by immunohistochemistry. Expression of beta1 integrin was determined by PCR and Western blotting. RESULTS: Exposure to EFs resulted in a cathodal-directed migration of RPE cells and a cathodal accumulation of F-actin and beta1 integrin in the cells. EF stimulation increased expression of beta1 integrin both in mRNA and protein levels. These effects could be inhibited by cytochalasin B. CONCLUSION: EFs induce directed migration of RPE cells, and this effect is, to some extent, regulated by the interaction between cytoskeleton and integrins.

Modulation of migration and Ca2+ signaling in retinal pigment epithelium cells by recombinant human CTGF.

PURPOSE: The migration of retinal pigment epithelium (RPE) cells is an initial step in the development of proliferative vitreoretinopathy (PVR). We investigated the expression of connective tissue growth factor (CTGF) in an in vitro model of wound healing and effects of recombinant human CTGF (rhCTGF) on modulating migration and Ca(2+) signaling in RPE cells. METHODS: Cultured human RPE monolayers were used to establish a wound-healing model. Western blot and in situ hybridization were used to detect the CTGF expression in RPE cells. Migration of RPE cells was measured under the stimulation of rhCTGF alone or in combination with dexamethasone (DEX) or 8-Br-cAMP. To determine the concentration of cytoplasmic-free Ca(2+) ([Ca(2+)]i) responding to CTGF, the fluo-3/AM-loaded RPE cells were observed with a laser scanning confocal microscope. RESULTS: The CTGF expression first increased after being wounded in RPE cells, then reached a peak and maintained at a high level. The positive expression was mainly at the edge of scrape and in motile RPE cells. rhCTGF-stimulated RPE cells migrated in a dose-dependent manner, and both DEX and 8-Br-cAMP could significantly inhibit the CTGF-induced migrations. CTGF induced a (Ca(2+))i elevation in RPE cells in a concentration-dependent manner. Moreover, stimulation of RPE cells with CTGF and DEX or 8-Br-cAMP counteracted the elevation of (Ca(2+))i induced by CTGF. CONCLUSIONS: The CTGF expression could be induced by an in vitro model of scrape wounding. rhCTGF stimulated the migration and Ca(2+) signal pathway in RPE cells in a dose-dependent manner, and DEX and 8-Br-cAMP suppressed this effect. Our results indicate that CTGF is involved in the wound-healing process and plays an important role in the pathogenesis of intraocular proliferative diseases.

Mechanical force enhances MMP-2 activation via p38 signaling pathway in human retinal pigment epithelial cells.

BACKGROUND: Rhegmatogenous retinal detachment and proliferative vitreoretinopathy (PVR) are eye diseases that are characterized by mechanical stress involving stretching of the retinal pigment epithelial (RPE) cells by the vitreous or the hyperplastic membranes. Here, we assessed whether mechanical force could change the expression of matrix metalloproteinases (MMPs) in RPE cells via the mitogen-activated protein kinase (MAPK) pathway. METHODS: Collagen-coated magnetite beads and magnetic fields were used to apply tensile forces to cultured RPE cells at focal adhesions. Activation of the MAPK, including extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 were determined over a time course from 5 to 30 min by Western-blot analysis. Activation of p38 was also tested using immunofluorescence staining. The mRNA levels of MMP-2, MMP-9, tissue inhibitor of MMP (TIMP)-2 and fibronectin (FN) were analyzed by RT-PCR. Active MMP-2 and MMP-9 were demonstrated by zymography. MMP-2 secretion was evaluated by enzyme immunoassay. RESULTS: Stimulation of RPE cells with mechanical stress did not change the total protein expression of the MAPK proteins ERK, JNK, and p38. However, of the three kinases, only active p38 showed an increased protein expression which was also shown by a 2.8-fold increase in immunofluorescence staining at 5 min following mechanical stress stimulation. This increase in active p38 expression was blocked by treating the cells with the p38 inhibitor SB203580. FN mRNA increased 2.4-fold at 15 min and MMP-2 mRNA increased 2.1-fold at 4 h. MMP-2 secretion increased 1.5-fold at 4 h and 1.9-fold at 12 h. The expression of MMP-2 and FN, and the activation and secretion of MMP-2, were inhibited in the presence of SB203580. The mRNA expression of MMP-9 and TIMP-2 did not change throughout. CONCLUSIONS: This study shows that mechanical stress upregulates MMP-2 and FN expression through activation of the p38 pathway. The increase in MMP-2 levels evoked by mechanical force may contribute to the remodeling of the extracellular matrix around RPE cells, weakening the interlinkage and membrane attachment between RPE cells, and facilitate cellular migration.

[Experimental study of acellular xenogenic dermal matrix and allogeneic sclera as wrapping materials for hydroxy apatite implantation].

OBJECTIVE: To observe the experimental results and histopathological changes of acellular xenogenic dermal matrix (X-ADM) and allogeneic sclera used as wrapping materials of hydroxy apatite (HA) ocular implants in New Zealand white rabbits. METHODS: Twenty-four rabbits received unilateral eye enucleating and the sockets were implanted with HA spherical implants wrapped with either acellular xenogenic dermal matrix or allogeneic sclera at random. The rabbits were examined for inflammation and implant exposure and sacrificed at 1, 2, 4, 6, 8 and 12 weeks after implantation. The sockets with the grafts were exenterated and the specimens were assessed histopathologically and ultrastructurally with light or transmission electron microscopy for the changes in inflammation reaction and vascularization. RESULTS: Compared to allogeneic sclera at the same stage of implantation, acellular xenogenic dermal matrix demonstrated more active and earlier growth of fibroblasts and new vessels with abundant collagen deposition. There were few inflammatory cells and no rejection was found. CONCLUSION: This experiment showed that the acellular xenogenic dermal matrix, with fast neovascularization and low immunity, can be an ideal material of ocular implant and a good substitute for allogeneic sclera.

[Cytoskeleton changes of cultured human retinal pigment epithelial cells in a mechanical stress model].

OBJECTIVE: To observe changes of the cytoskeleton of cultured human retinal pigment epithelium (hRPE) cells in a mechanical stress model in vitro. METHODS: Ferric oxide beads, coated with collagen, were added to dishes containing substrate-attached hRPE cells. After incubation, the cells were washed to remove unbound beads. The cells were pretreated by actin polymerization inhibitor cytochalasin D (0.05 mmol/L, 25 min). Before and 4, 8, 12 and 24 h after vertical magnetic force application the cells were stained for actin and vimentin using immunity fluorescence double labelled technique and analyzed with confocal microscopy. RESULTS: Four hours after force application, the polarity of hRPE cells was changed, and actin was polymerized into filaments in array of them along with the direction of the force. Cytoskeleton filaments were located mainly around the nucleus and the ferric oxide beads. Pretreatment with cytochalasin D, the same changes as described above occurred 8 h after magnetic force application. CONCLUSIONS: Mechanical force could induce changes of distribution of cytoskeleton in hRPE cells, which are some biological characteristics of muscle cells, and this may facilitate the cellular migration and proliferation.

[Effects of magnetic field on MAPK signaling pathways of human retinal pigment epithelial cells bound with beads in vitro].

OBJECTIVE: To observe the changes of mitogen activated protein kinase (MAPK) signaling pathways of human retinal pigment epithelial cells( RPEs) bound with beads under stretch caused by the force from magnetic field in vitro. METHODS: Ferric oxide microparticles, coAted with collagen, were added to dishes containing substrate-attached RPEs. After incubation, the cell layer bound with beads was laid in a magnetic field, the cells were stretched by the magnetic force. The activation status of the extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 in RPEs was determined over a time course from 3 to 30 minutes with western-blot analysis. To examine the role of p38 kinase in the response to stretching, cells were grown for 30 minutes in the presence or absence of inhibitor of p38 (SB203580). The changes of the expression of active p38 kinase were observed with fluorescence staining. RESULTS: Total ERK, JNK, and p38 were detected in RPEs. Active ERK and p38 were detected but active JNK was not detected. Activation of ERK was unchanged during the time course. In contrast, p38 activation was barely detected in the normal cells, but this stress-activated protein kinase exhibited a robust activation after 5 minutes in the magnetic field. SB203580 blocked the p38 activation during stretch stimulation. The stretch stimulation also increased the fluorescence staining of active p38. CONCLUSION: A magnetic field can affect RPEs bound with beads. The effect may be partially through p38 signaling pathway.

[Effects of mechanical stress on expressions of monocyte chemoattractant protein-1 and interleukin-8 of cultured human retinal pigment epithelial cells].

OBJECTIVE: To investigate the expressions of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) of cultured human retinal pigment epithelial (hRPE) cells under mechanical stress in vitro, so as to mimic and understand the role of these 2 inflammatory cytokines in the early stage of development of primary retinal detachment. METHODS: Ferric oxide beads coated with collagen were added to the culture plate containing wall-attaching hRPE cells and then the cells were incubated and washed to remove the unbound beads. A magnet was put to the culture plate to provide vertical magnetic force. Cytochalasin D (CD) was added to the culture fluid to inhibit the phagocytizing, secreting, and moving functions of the hRPE. Before the experiment and 15 min, 0.5 h, 1 h, 4 h, and 8 h the beginning of experiment, the MCP-1 mRNA and IL-8 mRNA in the hRPE cells were measured with reverse transcriptase polymerse chain reaction (RT-PCR), and the MCP-1 and IL-8 protein expression in the supernatants was tested with enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: MCP-1 and IL-8 mRNA were expressed at very low levels in the RPE cells and supernatant not exposed to magnetic force. After exposure to magnetic force, both MCP-1 and IL-8 mRNA demonstrated "double peaks" expression. Their first peak levels appeared within 0.5 h, being 3.30 ng/L +/- 0.12 ng/L and 1.88 ng/L +/- 0.08 ng/L respectively. The first peaks of MCP-1 and IL-8 protein expression were within 1 h, being 552.05 ng/L +/- 7.64 ng/Land 236.67 ng/L +/- 14.30 ng/L respectively, and the second peaks appeared about 4 hours later. After cytochalasin D pretreated, the expression and secretion of both MCP-1 and IL-8 of the hRPE cells were significantly decreased to the levels of 2.36 ng/L +/- 0.27 ng/L and 1.64 ng/L +/- 0.08 ng/L, and 353.80 ng/L +/- 16.68 ng/L and 101.86 ng/L +/- 15.92 ng/L respectively. CONCLUSION: Mechanical stress induces the RPE cells to express MCP-1 and IL-8, and this effect was inhibited in part by pretreatment of CD, indicating that the cytoskeleton may be involved in the effect and that these two inflammatory cytokines take a part in the early stage of development of primary retinal detachment.

Transscleral suture technique for fixation of a dislocated posterior chamber intraocular lens.

We describe a double-loop-knot technique for repositioning a displaced posterior chamber intraocular lens (IOL) that facilitates placement of scleral fixation sutures around the haptic for IOL stabilization. The technique minimizes the intraocular manipulations necessary to create a suture loop around the haptic of a dislocated IOL as well as scleral incisions required for IOL exchange.