[Diabetic maculopathy]

Diabetic maculopathy is the result of multifactorial and complex alterations of the retinal capillaries in association with diabetes mellitus and is divided into two forms, ischemic maculopathy and diabetic macular edema. Diabetic macular edema is the leading cause of blindness among people of working age. The functional and morphological results of intravitreal pharmacotherapy in cases of fovea-involving macular edema using vascular endothelial growth factor (VEGF) inhibitors such as ranibizumab and aflibercept obtained in large randomized clinical trials are excellent and are superior to results obtained with focal or grid laser coagulation alone. Steroids including dexamethasone and fluocinolone implants represent approved alternatives, although flucinolone is considered a second-line therapy in refractory and chronic cases. VEGF inhibitors can be used in different treatment strategies such as PRN and treat and extend strategies. Focal laser photocoagulation remains the gold standard for macular edema not involving the fovea (and therefore usually good visual acuity). Laser is also still indicated as a panretinal photocoagulation of peripheral retinal ischemic areas in order to prevent neovascular complications. It remains to be proven whether panretinal photocoagulation can have an effect on the treatment intervals of intravitreal pharmacotherapy, too. Surgical treatments such as vitrectomy are today limited to cases of macular edema with concomitant obvious tractional pathologies at the vitreoretinal interface.

EGFR-blockade with erlotinib reduces EGF and TGF-β2 expression and the actin-cytoskeleton which influences different aspects of cellular migration in lens epithelial cells

INTRODUCTION

After cataract surgery, residual lens epithelial cells migrate and proliferate within the capsular bag resulting in posterior capsule opacification (PCO). The up-regulation of TGF-β2, EGF and FGF-2 has been identified as a key factor in PCO pathogenesis leading to actin fiber assembly and alterations in the migration pattern. In this in vitro study, the influence of Erlotinib as a selective EGFR inhibitor is investigated on the cellular features indicated, which might promote a future clinical application.

METHODS

Expression of EGF, FGF-2 and TGF-β2 was measured using RT-PCR and ELISA in human lens epithelial cells (HLEC). Computational data of an in vitro time lapse microscopy assay were used for statistical analysis of single cell migration with a particular focus on cell-cell interaction; cell velocity distribution; and displacement before, during and after mitosis. The effect of Erlotinib on the actin-cytoskeleton was evaluated using Alexa Fluor 488 Phalloidin and epifluorescence microscopy.

RESULTS

EGF and TGF-β2 mRNA expression and protein levels are reduced by Erlotinib, while FGF-2 expression remained stable. Overall fluidity of cell-cell interaction is less in the presence of Erlotinib compared to the control and the velocity distribution across all cells becomes less uniform within the cell cluster. After mitosis, HLEC move significantly faster without EGFR inhibition, which can be completely blocked by Erlotinib. Furthermore, Erlotinib diminishes the amount of actin stress fibers and the stress fiber diameter.

CONCLUSION

As a novel effect of Erlotinib on HLEC, we describe the down-regulation of EGF and TGF-β2 expression, both are crucial factors for PCO development. Cellular movement displays complex alterations under EGFR inhibition, which is partly explained by actin fiber depletion. These findings further underline the role of Erlotinib in pharmacologic PCO prophylaxis.

Attenuation of human lens epithelial cell spreading, migration and contraction via downregulation of the PI3K/Akt pathway

BACKGROUND

Posterior capsule opacification (PCO) represents a major challenge in the postoperative management of cataract patients. Spreading, migration and contraction of residual human lens epithelial cells play a pivotal role in the pathogenesis of PCO. Therefore, we analyzed the effect of the alkylphosphocholine (APC) erufosine on these cellular features as well as on PI3K/Akt, a crucial pathway in PCO pathogenesis.

METHODS

Human lens epithelial cells were cultured under standard cell culture conditions. Cell spreading was analyzed on fibronectin-coated wells and chemokinetic migration was assessed by time-lapse microscopy. For evaluation of cell-mediated collagen matrix contraction, the cells were seeded into collagen gels and incubated with an APC in different non-toxic concentrations before the surface area was measured on day 6. The activity of PI3K/Akt was assessed by an ELISA kit after incubation of the cells with different APC concentrations.

RESULTS

Human lens epithelial cell spreading and migration were attenuated by APCs as follows: 7 % spreading, 48 % migration (0.1 μM APC), and 32 % spreading, 68 % migration (1.0 μM APC). APC concentrations of 0.1 μM reduced collagen gel diameter by 5 %, and 1.0 μM by less than 1 %, compared to untreated, cell-populated gels that resulted in a cell diameter contraction of 36 %. PI3K was downregulated in a concentration-dependent manner.

CONCLUSIONS

The crucial cellular features of PCO pathogenesis are attenuated by the APC erufosine via downregulation of the PI3K pathway. Thus, erufosine might become a valuable tool for pharmacologic PCO prophylaxis in the future.

Twelve-month experience with Ozurdex for the treatment of macular edema associated with retinal vein occlusion

PURPOSE

To evaluate the efficacy and safety of a dexamethasone implant (Ozurdex) alone or in combination with bevacizumab.

METHODS

Sixty-four eyes were prospectively investigated. Group 1 (22 central retinal vein occlusion (CRVO) and 16 branch retinal vein occlusion (BRVO)) was treated with Ozurdex alone, and group 2 (14 CRVO and 12 BRVO) was treated with three consecutive bevacizumab injections followed by Ozurdex. Recurrences were treated with Ozurdex only. Patients were seen preoperatively and thereafter in monthly intervals. The primary end point was best-corrected visual acuity (BCVA) at 12 months.

RESULTS

In group 1, BCVA improved by 6.6 (±1.7) letters in CRVO and 7.8 (±2.9) in BRVO patients, and in group 2 by 9.8 (±1.0) vs 9.4 (±2.1) letters. A significant difference was only seen between CRVO patients in group 1 and 2 at 12 months (P<0.05). Recurrence after the first Ozurdex injection occurred after 3.8 (CRVO) and 3.5 months (BRVO) in group 1, vs 3.2 and 3.7 months in group 2. Elevated intraocular pressure (>5 mm Hg) was measured in approximately 40% cataract progression requiring surgery in about 50% of eyes after three Ozurdex injections.

CONCLUSION

Combined treatment showed slightly better functional outcome for CRVO patients. Increased intraocular pressure and cataract progression was frequent and should be considered when an individual treatment is planned.

[Navigated focal retinal laser therapy using the NAVILAS® system for diabetic macula edema]

PURPOSE

The aim of this study was to investigate the accuracy of a navigated laser photocoagulator in clinically significant macular edema (CSME).

METHODS

Focal laser treatment for diabetic macular edema (DME) in 36 patients was digitally planned on fundus images and performed with navigation using NAVILAS® (OD-OS, Teltow, Germany). Treatment intensity was controlled visually during treatment so the laser spots applied were barely directly visible after treatment. Using color images (CI) and optical coherence tomography (OCT) 4,137 laser spots (mean 115 per eye) were analyzed at 1 month follow-up and accuracy of spot placement was determined.

RESULTS

In total 79% of laser spots were visible on CI of which 96% were within 100 µm of the planned target position. On an intention-to-treat (ITT) basis, 76% of the laser spots were placed and visible within the 100 µm target and OCT confirmed that laser effects were limited to the outer retina. The mean time for focal treatment was < 7 min (±3 min).

CONCLUSIONS

After NAVILAS treatment for DME a high percentage of laser effects could be visualized on post-treatment color images and the location showed high concordance with the preplanning target.

[Significance of ophthalmological imaging in common hereditary retinal diseases]

BACKGROUND

Over the past years, a significant progress in genetic, functional and imaging diagnostics in hereditary retinal diseases has been made. Optical coherence tomography (OCT) as well as fundus autofluorescence (FAF) allow for high-resolution, non-invasive imaging - from various perspectives - of retinal and choroidal layers of the posterior fundus. Both techniques have gained more and more significance in the diagnosis of hereditary retinal diseases.

PATIENTS/METHODS

Of all patients presented in this review, extensive family history was taken and a clinical ophthalmological examination performed. OCT scans as well as FAF images were acquired and compared to results of other functional and molecular genetic tests in the context of each disease.

RESULTS

The presented cases in this review addressing hereditary retinal diseases (Best's disease, Stargardt's disease, cone-rod dystrophy, retinitis pigmentosa, achromatopsia, and X-linked retinoschisis) show the significance of ophthalmic imaging (OCT + FAF) for a targeted diagnosis of hereditary retinal diseases.

CONCLUSION

The described imaging techniques (OCT + FAF) are becoming more and more important in the diagnosis of hereditary retinal diseases. Due to increasing availability of the devices, earlier detection of typical morphological changes not seen in clinical fundoscopy is feasible.

[Alkylphosphocholines inhibit lens epithelial cell proliferation and attachment]

BACKGROUND

Posterior capsule opacification (PCO) is one of the major concerns in modern cataract surgery. Ten years after successful surgery, Nd:YAG capsulotomy is required in up to 42% of patients with an acrylic sharp-edged intraocular lens (IOL). Some accommodative and multifocal IOLs display even higher capsulotomy rates. Pharmacologic prophylaxis with alkylphosphocholines (APCs) could be a novel option in PCO prevention.

METHODS

The human lens epithelial cell line HLE-B3 served as an in-vitro model. After incubation with APCs in different concentrations (0.01, 0.1, and 1 mM), the trypan blue exclusion assay and the live/dead test were performed at serum concentrations of only 5%. Cell proliferation was assessed with the MTT test. Evaluation of cell attachment was done with fibronectin- and laminin-coated wells.

RESULTS

APCs can inhibit the proliferation of human lens epithelial cells in the presence of only 5% serum in a dose-dependent manner. Proliferation inhibition of 60% and attachment inhibition of about 50% were reached at concentrations of 0.1 µM.

CONCLUSION

APCs inhibit proliferation and attachment of human lens epithelial cells in nontoxic concentrations in vitro. The substance can be applied topically, and an intraoperative application for pharmacologic PCO prophylaxis is feasible.

[Intracameral moxifloxacin: a safe option for endophthalmitis prophylaxis? In vitro safety profile for intraocular application]

BACKGROUND

Moxifloxacin (Vigamox), a 4th-generation fluoroquinolone, covers most isolates causing endophthalmitis. It is safe and effective for systemic and topical use; however, only very limited data are available on prophylactic intracameral administration to prevent endophthalmitis. This study investigated the safety of Vigamox for intracameral application in a cell-culture model.

METHODS

The endothelial toxicity of moxifloxacin (Vigamox) was evaluated in cultured human corneas. Primary human retinal pigment epithelium cells (RPEs), trabecular meshwork cells (TMCs), lens epithelium cells (LECs), and corneal endothelial cells (CECs) were treated with concentrations of Vigamox. Toxic effects were evaluated after 24 h (MTT assay and live-dead assay). By treating TMC, CEC, and RPE cells either with oxidative stress or tumor necrosis factor-alpha (TNF-a), lipopolysaccharide (LPS), and interleukin-6 (IL-6), the effects of moxifloxacin on cellular viability under conditions of inflammation were investigated.

RESULTS

No corneal endothelial toxicity could be detected after 30 days of treatment with moxifloxacin 500 microg/ml. Primary RPEs, TMCs, LECs, and CECs showed adverse effects on proliferation and viability only at concentrations higher than 150 microg/ml moxifloxacin. After preincubation with TNF-a, LPS, and IL-6 for 24 h and subsequent treatment with moxifloxacin at concentrations of 10-150 microg/ml for 24 h, no significant decrease in proliferation or viability was observed. H2O2 exposure did not increase cellular toxicity

CONCLUSION

Vigamox did not show significant toxicity on primary RPEs, TMCs, LECs, CECs, or human corneal endothelium at concentrations up to 150 microg/ml. The MIC90 of moxifloxacin for pathogens commonly encountered in endophthalmitis is known to be in the range of 0.25-2.5 microg/ml. Therefore, intracameral use of Vigamox at concentrations up to 150 microg/ml may be safe and effective for preventing endophthalmitis after intraocular surgery.

Sorafenib protects human optic nerve head astrocytes from light-induced overexpression of vascular endothelial growth factor, platelet-derived growth factor, and placenta growth factor

OBJECTIVES

Growth factors, such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and placenta growth factor (PlGF) are key players in the development of diabetic retinopathy, age-related macular degeneration, and other retinal neovascular diseases. Glial cells provide a significant source of retinal growth factor production under physiologic and pathologic conditions. Cumulative light exposure has been linked to increased retinal growth factor expression. Previous reports indicate that sorafenib, an oral multikinase inhibitor, might have a beneficial effect on retinal neovascularization. This study was designed to investigate the effects of sorafenib on light-induced overexpression of growth factors in human retinal glial cells.

METHODS

Primary human optic nerve head astrocytes (ONHAs) were exposed to white light and incubated with sorafenib. Viability, expression, and secretion of VEGF-A, PDGF-BB, and PlGF and their mRNA were determined by reverse transcription-polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay.

RESULTS

Light exposure decreased cell viability and increased VEGF-A, PDGF-BB, and PlGF expression and secretion. These light-induced effects were significantly reduced when cells were treated with sorafenib at a concentration of 1 microg/ml.

CONCLUSION

Sorafenib significantly reduced light-induced overexpression of VEGF-A, PDGF-BB, and PlGF in primary human ONHAs. Sorafenib has promising properties as a potential supportive treatment for retinal neovascularization.

Endophthalmitis: Pathogenesis, clinical presentation, management, and perspectives

Endophthalmitis is a rare but sight-threatening complication that can occur after ocular surgery or trauma or as a consequence of systemic infection. To optimize visual outcome, early diagnosis and treatment are essential. Over recent decades, advances in hygienic standards, improved microbiologic and surgical techniques, development of powerful antimicrobial drugs, and the introduction of intravitreal antibiotic therapy have led to a decreased incidence and improved management of endophthalmitis. However, endophthalmitis still represents a serious clinical problem. This review focuses on current principles and techniques for evaluation and treatment of endophthalmitis. In addition, it addresses recent developments regarding antimicrobial treatment and prophylaxis of infectious endophthalmitis.

Intracameral voriconazole: in vitro safety for human ocular cells

Fungal keratitis is a sight-threatening infection of the cornea. It sometimes leads to loss of the eye. Despite an expanding range of fungal pathogens, there are only few therapeutic agents for its treatment available. Voriconazole is a second-generation synthetic triazole with a broad action against yeasts and molds. The current study investigates the safety of voriconazole for intracameral application in a cell culture model. Endothelial toxicity of voriconazole was evaluated in cultured human corneas. Possible toxic effects of voriconazole (10 microg /mL-10mg/mL) in corneal endothelial cells (CEC), primary human trabecular meshwork cells (TMC), and primary human retinal pigment epithelium (RPE) cells were evaluated after 24h and under conditions of inflammatory stress by treatment with tumor-necrosis-factor alpha (TNF-alpha), lipopolysaccharides (LPS), or interleukin-6 (IL-6) and hydrogen peroxide. Toxicity was evaluated by tetrazolium dye-reduction assay, and cell viability was quantified by a microscopic live-dead assay. No corneal endothelial toxicity could be detected after 30 days of treatment with 250 microg /mL of voriconazole. Concentrations up to 1mg/mL had no influence on CEC, TMC, or RPE cell proliferation, or on cell viability when administered for 24h. Hydrogen peroxide exposure did not increase cellular toxicity of voriconazole at concentrations from 10 to 250 microg /mL. After preincubation with TNF-alpha, LPS, or IL-6 for 24h and subsequent voriconazole treatment for 24h, no significant decrease in proliferation or viability was observed. This study showed no significant toxicity for voriconazole on CEC, TMC, RPE cells, or human corneal endothelium when administered in therapeutic concentrations up to 250 microg /mL.

Bevacizumab wirkt nicht toxisch auf Zellen des menschlichen Auge

OBJECTIVE

Intravitreal anti-vascular endothelial growth factor (VEGF) treatment with bevacizumab (Avastin) has emerged as a promising therapy for the treatment of choroidal neovascularisation in age-related macular degeneration. Intravitreal administration of bevacizumab is "off-label," and only very limited data regarding short-term toxicity exist. Therefore, we investigated the safety of different doses of bevacizumab on the anterior- and posterior-segment cells of the human eye.

METHODS

Primary human retinal pigment epithelium (RPE) cells, human optic nerve head astrocytes (ONHA), human trabecular meshwork cells (TMC), and cornea buttons not suitable for transplantation were treated with bevacizumab (25 microg/ml, 250 microg/ml, and 2,500 microg/ml) for 48 h, corresponding to 0.1x, 1x, and 10x the dosage used intravitreally. Bevacizumab-related toxicity was evaluated by a colorimetric test (MTT) measuring inhibition of RPE, ONHA, and TMC cell proliferation. Additionally, cell viability was quantified by live/dead fluorescence assay. Corneal endothelium was quantified by phase-contrast microscopy.

RESULTS

Bevacizumab showed adverse effects on primary RPE cell proliferation as well as on cell viability at a concentration of 2,500 microg/ml. The lower concentrations of 25 microg/ml and 250 microg/ml had no influence on RPE cell proliferation or cell viability. There was no toxicity for any investigated concentration on human ONHA, TMC, or corneal endothelium.

CONCLUSION

In this study, a 10-fold concentration (compared with common clinical use) of the VEGF-blocking antibody bevacizumab had toxic effects on primary RPE. There was no toxicity for lower concentrations or toxicity to other cell types of the anterior and posterior segments. Therefore, the clinical use of bevacizumab at concentrations of 1-1.25 mg intravitreally seems to be safe.