Tomoyasu Shiraya

Protective Role of Glutathione Peroxidase 4 in Laser-Induced Choroidal Neovascularization in Mice

Purpose To evaluate the influence of glutathione peroxidase 4 (GPx4) expression in retinal pigment epithelium (RPE)/choroid tissue using a mouse model of laser-induced choroidal neovascularization (CNV). Methods In this study, GPx4+/−, GPx4+/+, and GPx4-overexpressing transgenic mice were created for comparison. The mRNA and protein expression of vascular endothelial growth factor (VEGF)-A in RPE/choroid tissue were evaluated before and after CNV induction by laser. Moreover, we investigated the changes in the VEGF-A mRNA level in RPE/choroid tissue in the CNV model that have not been clearly shown previously. Lipid peroxidation in RPE/choroid tissue was evaluated by immunohistochemistry using antibody against 4-hydroxy-2-nonenal. To investigate the protective role of GPx4, the size of laser-induced CNV was compared on day 7 among the mice expressing different levels of GPx4. Results In the laser-induced CNV mouse model, laser treatment reduced the VEGF-A mRNA level in RPE/choroid tissue, while it increased the VEGF-A protein level. Evaluation of VEGF-A expression in RPE/choroid tissue of the GPx4+/−, GPx4+/+, and GPx4 transgenic mice revealed that GPx4 increased the VEGF-A protein level under physiological conditions (i.e., without laser treatment), while GPx4 suppressed the increase in the VEGF-A protein level under pathological conditions (i.e., after CNV induction by laser). In addition, GPx4 reduced the CNV size in a dose-dependent manner in vivo. Conclusions GPx4 suppresses the increase in the VEGF-A protein level, which occurs during the development of pathological CNV, thus partly explaining the protective effect of GPx4 against CNV.

Aqueous cytokine levels are associated with reduced macular thickness after intravitreal ranibizumab for diabetic macular edema

Purpose It is controversial whether the administration of anti-vascular endothelial growth factor drugs for diabetic macular edema (DME) affects intraocular inflammatory cytokines. In this study, we measured cytokine concentration in aqueous humor before and after intravitreal injection of ranibizumab (IVR). The aim was to determine changes in cytokine concentration and their effects on DME reduction. Methods Twelve patients (13 eyes) with DME received two IVR (0.5 mg) with a 1 month interval, and a total of 26 aqueous humor samples were obtained. Macular thickness was measured with an optical coherence tomography (OCT) using thickness-map mode with an Early Treatment Diabetic Retinopathy Study (ETDRS) 9-zone grid that was divided into two zones: a central circle with a diameter of 1 mm (zone1); and an outer circle with a diameter of 6 mm (zone2). Results The concentration of eotaxin-1 in aqueous humor samples decreased significantly after IVR. Baseline cytokine concentration was associated with IVR-induced DME reduction. In zone1, higher baseline concentration of interferon-induced protein (IP)-10, and in zone 2, higher baseline concentration of granulocyte-macrophage colony-stimulating factor, IP-10, and tumor necrosis factor (TNF) α; and lower baseline concentration of eotaxin-1, interleukin (IL)-5, and IL-8 were associated with improved DME. Cytokine changes were associated with IVR-induced DME reduction. In zone1, lower concentration of IP-10 compared to baseline or higher concentration of macrophage inflammatory protein (MIP) -α, and in zone 2, lower concentration of IL-5 compared to baseline, IL-8, and IP-10 or higher concentration of eotaxin-1 and MIP-1β were associated with improved DME. Conclusions These findings suggest that ranibizumab affects the concentration of cytokines in aqueous humor. Various cytokines contribute to a decrease in retinal thickness, both in the center of the macula and in a larger area of the retina.

Comparison of burn size after retinal photocoagulation by conventional and high‐power short‐duration methods

assessments every 2 months to detect recurrences with shorter delay. Our results point out the need for reinjection every 5 months, with good results on CMT and VA in real life (Fig. 1). Financial disclosures outside the subject of this work: Dr Krivosic received honoraria for board membership, consultancy, lectures and received reimbursement of travel and meeting expenses from Allergan, Bayer and Novartis. Dr Bheekee has no financial disclosure. Dr Mich ee has no financial disclosure. Dr Delyfer has no financial disclosure. Pr Tadayoni received honoraria for board membership, consultancy, lectures and educational presentation, and received reimbursement of travel and meeting expenses from Alcon, Allergan, Alimera, Bausch & Lomb, Bayer, Dorc, FCI, Novartis, Pfizer, Servier and Takeda. Pr Korobelnik received honoraria for board membership, consultancy, lectures and educational presentation, and received reimbursement of travel and meeting expenses from Alcon, Allergan, Bayer, Carl Zeiss Meditec, Novartis, Roche and Thea.

Influence of a yellow-tinted intraocular lens on laser beam transmittance.

Acta Ophthalmol. 2011: 89: 37–39

Effect of intravitreal ranibizumab injection on aqueous humour cytokine levels in patients with diabetic macular oedema.

Editor, T here is evidence to indicate that inflammatory cytokines, as well as vascular endothelial growth factor (VEGF), play an important role in the development of diabetic macular oedema (DME). Recently, intravitreally injected ranibizumab (IVR) (Lucentis; Novartis, Basel, Switzerland and Genentech Inc., South San Francisco, CA, USA) has been shown to suppress inflammatory cytokines and chemokines that promote adhesion to vascular endothelium or mobilize inflammatory cells by inhibiting multiple isoforms of VEGF-A (Ferrara et al. 2006). Campochiaro et al. (2009) reported that VEGF levels in the aqueous humour were significantly higher in patients with DME (528 112 pg/ml) than in patients with branch retinal vein occlusion (35 3 pg/ml). Muether et al. (2014) measured VEGF levels in the aqueous humour of DME patients receiving IVR, using Luminex, and reported that VEGF levels were completely suppressed in all patients receiving IVR treatment. In this study, we focused on the inflammatory cytokines thought to be involved in DME and analysed its levels that could measure for systematically to identify the changes after treated with ranibizumab. A total of 26 aqueous humour samples obtained from 13 eyes of 12 patients with DME were collected. (Patients’ mean age, 62.5 11.9 years, mean Hb-A1c, 7.0 1.3%, visual acuity, logMAR 0.47 0.25, mean central foveal thickness, 570.0 109.8 lm). A history of focal laser photocoagulations in two eyes was noted. A history of pan-retinal laser photocoagulations was noted for eight eyes. Intravitreal injections of ranibizumab (IVR) was performed twice in each patient. Undiluted aqueous humour samples were obtained during the IVR treatment as follows: a pre-IVR sample was taken during the initial IVR, and a second sample (post-IVR sample) was taken after completion of the second round of IVR, which was conducted 1 month after the initial IVR treatment. Individuals who had undergone previous vitreous surgery or who had already received intravitreal injections of bevacizumab were excluded from this study. Approval for this prospective study was obtained from the Institutional Review Board of our institution. Informed consent was obtained prior to study entry. A multiplex bead-based immunoassay, Luminex 100 multiplex array assay (Luminex Corporation, Austin, TX, USA), was used to measure the levels of 36 cytokines and chemokines in each aqueous humour sample. Then, nine cytokines levels were detected, which were examined between pre-IVR and post-IVR. Of note, eotaxin-1 levels in aqueous humour samples significantly decreased after IVR (p < 0.05, paired t-test, Table 1). In addition, interleukin (IL)6 levels were also measured and analysed in samples from 12 eyes and also showed a tendency to decrease after IVR treatment. Although eotaxin-1 that was shown in this study has been reported for the characteristics in a field of age-related macular degeneration (AMD), this is the first study to show that IVR treatment reduces the levels of eotaxin-1 in the aqueous humour of DME patients. According to a previous report in AMD patients, eotaxin-1 (also known as CCL11) binds to the CCR3 receptor, and the subsequent signalling between this receptor and VEGF is particularly important to express choroidal neovascular endothelial cells in humans with AMD. Furthermore, blockade of CCR3 was more effective than VEGF neutralization in reducing choroidal neovascularization (CNV) (Kim et al. 2015). Although the pathogenesis of AMD and DME may differ, reducing eotaxin-1 levels would be expected to be a more effective function of DME therapy, due to the previously reported molecular biological interaction between VEGF and CCR3.

A case of diabetic retinopathy with both retinal neovascularization and complete posterior vitreous detachment

Purpose Report of a case with retinal neovascularization developing in the setting of diabetic retinopathy despite complete posterior vitreous detachment (PVD). CASE REPORT. A 76-year-old man had had type II diabetes mellitus for more than 30 years. Weiss’ ring was detected by direct and indirect ophthalmoscopy. PVD was thus considered to be complete. On the other hand, fluorescein angiography showed two areas of hyper-fluorescence at the margin of the retinal nonperfusion area. Conclusions The present case underscores the importance of periodic follow-up using fluorescein angiography, given the probability of retinal neovascularization development and proliferative changes for many years even in diabetic retinopathy associated with complete PVD.

Experimental verification of subthreshold laser therapy using conventional pattern scan laser

Purpose Leading-edge therapeutic laser technologies are not available at every medical facility; therefore, alternative approaches incorporating novel advances in digital and laser technology into more readily available conventional methods have generated significant research interest. Using a rabbit model, this study investigated whether the algorithm used in the Endpoint Management (EM) software system of the latest devices could enable subthreshold laser treatment in conventional retinal tissue laser therapy systems. Materials and methods Two types of devices were used, the PASCAL Streamline 577 and the MC 500-Vixi™, and the laser method was classified into three categories: EM; single-shot using PASCAL with arbitrary energy settings (PSS-SDM); and MC500-VixiTM (VX-SDM), which were performed in eight eyes from four Dutch-Belted rabbits. In EM, 100 mW (100%) was set as a landmark, and the laser energy parameters were gradually decreased to 80%, 60%, 50%, 40%, 30%, 20%, and 10%, using a 2 × 3 square pattern. In PSS-SDM and VX-SDM, as control, the laser energy was gradually decreased to 100, 80, 60, 50, 40, 30, 20, and 10 mW. The laser settings were fixed at 200 μm, 20 ms, and a wavelength of 577 μm. To identify and compare the extent of tissue damage at each spot size, optical coherence tomography (OCT) and histological findings were used to construct a three-dimensional histopathology image using a confocal laser scanning fluorescence microscope. Results The spot size at 50% setting on EM was 7183 μm2; PSS-SDM required 50 mW (5503 μm2) to 60 mW (10279 μm2) and VX-SDM required 50 mW (7423 μm2) to create the approximate spot size. Furthermore, at 50 mW of PSS-SDM and VX-SDM, the extent of tissue damage in all three methods was generally in accord with the outer nuclear layer by OCT and inner nuclear layer by histopathological imaging. Conclusion These findings suggest that it may be possible to perform subthreshold laser therapy using approximations from the EM algorithm.

Comparison of burn sizes resulting from photocoagulation using a transpupillary laser and an endolaser

Editor, A lthough retinal photocoagulation is an essential treatment for ischaemic retinal diseases, visual field loss can occur by atrophic creep (Fong et al. 2007). According to Maeshima, laser scars created with a transpupillary laser were larger (Maeshima et al. 2004). However, a comparison of the size of retinal photocoagulation burns caused by a transpupillary laser (TL) versus an endolaser (EL) during vitrectomy has not yet been reported. Herein, we compared the burn expansion ratio in the medium term. Subjects were classified into two groups based on the performance of retinal photocoagulation by the TL or EL method for the treatment of ischaemic retinal disease. All data were retrospectively collected and analysed. Seven eyes from seven patients who underwent TL photocoagulation (TLP) and 140 associated photocoagulation spots (20 laser spots per eye) were included in the analyses. Eight eyes from eight patients who underwent EL photocoagulation (ELP) during vitrectomy and 160 associated photocoagulation spots were likewise included in the analyses. The mean patient age was 66 years (SD 9) and 68 years (SD 7), and the refraction values were -0.8 dioptres (SD 1.3) and -0.4 dioptres (SD 0.9) in the TL and EL group, respectively. No significant differences existed between the patient age and refraction for the two groups (age, p = 0.633; refraction, p = 0.548; unpaired t-test). TL photocoagulation was performed using the NOVUS Omni (Lumenis, Santa Clara, CA, USA) with an applied size of 200 lm, 120 (range: 100–150) mW for 200 msec with green wavelength (521 nm) using Mainster PRP165 lenses (Ocular Instruments Inc., Bellevue, WA, USA). An endolaser power of 150 mW was applied to the retina for 300 msec using a 25gauge system laser probe (PURE POINT LASER; Alcon, Ft Worth, TX, USA). The resulting photocoagulation spots created by both procedural methods were barely discernible. Digital fundus photographs, obtained twice following photocoagulation, were used to assess posterior pole burn size by a single physician, who was masked to the photocoagulation method used. Photocoagulation spot area was calculated by multiplying the vertical and horizontal diameters (measured in pixels, set as ‘PIXEL) of 20 posterior pole spots outside of the macular vessels. The expansion ratio was determined by comparing photocoagulation spots in the first and second photographs. The first measurement of burn size was defined as baseline to avoid measurement error induced by early retinal oedema. The first and second digital fundus photographs were taken 69 (SD 26) and 277 days (SD 49) following TLP, respectively, and 98 (SD 52) and 334 days (SD 53) following ELP, respectively. Postprocedural timing of fundus photography was 209 days (SD 34) in the TL group and 236 days (SD 15) in the EL group, which was not significantly different between the two groups (p = 0.069, unpaired t-test). The first and second burn size (PIXEL) measurements were 498 (SD 119) and 584 (SD 142), respectively, following TLP and 837 (SD 336) and 1030 (SD 381), respectively, following ELP. Consequently, the burn expansion ratio in the TLP group was 1.18 (SD 0.15), which was significantly slower than the 1.27 (SD 0.21) expansion ratio in the ELP group (p = 0.000096, unpaired t-test). The scattergram indicated a relationship between the first measurement and the expansion ratio for both TL and EL (Fig. 1). The generalized estimating equation (GEE) was also used to examine correlations between observations in the same participants, while adjusting for differences in photocoagulation spot diameters at the time of the first measurement. The analyses also showed that the burn expansion ratio after photocoagulation was larger in spots created with EL than in those created with TL (p = 0.0001). The results indicated thatELmayhave hypercoagulable tendencies and reduced tissue selectively compared with TLP.

Vitreous hemorrhage and fibrovascular proliferation after laser-induced chorioretinal venous anastomosis

AIM To describe a case in which vitrectomy was required for vitreous hemorrhage and fibrovascular proliferation after laser-induced chorioretinal venous anastomosis (LCVA) for non-ischemic central retinal vein occlusion (CRVO). METHODS Observational case report. RESULTS A 72-year-old man complained of central scotoma in the left eye, and was diagnosed as suffering from non-ischemic CRVO. LCVA was performed in another hospital. Although favorable visual function was briefly maintained postoperatively,severe vitreous hemorrhage developed in his left eye, necessitating vitrectomy. CONCLUSION Considering that LCVA carries a risk of serious complications, we must apply this treatment with caution, especially in ethnic groups, such as the Japanese, in whom pigmentation reacts to photocoagulation excessively.