Differences in collateral vessel formation after experimental retinal vein occlusion in spontaneously hypertensive rats and wild-type rats.

Objective: Retinal vein occlusion (RVO) can lead to visual impairment, but the development of collateral vessels can sometimes mitigate significant damage. This study aimed to investigate the relationship between collateral vessels and hypertension, the most common underlying condition associated with RVO, by comparing spontaneously hypertensive rats (SHRs) and wild-type Wister rats (WWRs). We also examined the differences between WWRs and SHRs in terms of sphingosine 1-phosphate receptor 1 (S1PR1) expression and its product nitric oxide synthase 3 (NOS3) expression, which are involved in the formation of collateral vessels after vascular occlusion. Methods: Laser photocoagulation (PC) was used to occlude one randomly selected retinal vein in WWRs and SHRs, and the area surrounding the occluded vessel was examined using optical coherence tomography angiography. If reperfusion of the occluded vessel occurred within 2 weeks, the vessel was re-occluded repeatedly by PC. The number of eyes with successfully occluded vessels accompanied by collateral vessels was recorded. Then, WWRs and SHRs were divided into the following four groups: 1) control (no treatment), 2) vehicle (20% DMSO), 3) S1PR1 agonist (2 mg/mL SEW2871), and 4) S1PR1 antagonist (0.25 mg/mL VPC 23019) groups. The drugs were administered intravitreally in all groups except the control. The number of laser shots required for successful RVO was recorded. Histological evaluation and quantitative real-time PCR of S1PR1 and NOS3 were performed to elucidate the mechanisms underlying collateral vessel formation. Results: The proportion of eyes achieving successful vein occlusion was lower in SHRs (4/12 eyes, 33.3%) than in WWRs (8/10 eyes, 80%, p = 0.043). NOS3 expression at 6 h after PC was significantly higher in WWRs than in SHRs (p = 0.021). In WWRs treated with SEW2871, vein occlusion failed in 7 of 10 eyes (70%). The expression of NOS3 was significantly higher in the SEW2871 treatment group than in the untreated group (p < 0.001). Furthermore, NOS3 expression was significantly higher after SEW2871 treatment in WWRs than in SHRs (p = 0.011). Conclusion: In hypertensive environments, collateral vessels are less likely to develop, and S1PR1 may be involved in this phenomenon.

Treatment strategy for BVO-ME based on long-term outcomes correlating retinal structure by OCT image and visual acuity.

BACKGROUND: Intravitreal anti-vascular endothelial growth factor (VEGF) is a mainstream treatment for reducing ME secondary to BRVO (BVO-ME). Regrettably, most reports of intravitreal anti-VEGF for BVO-ME have disclosed only short-term outcomes. Here, we characterized long-term indicators for the visual prognosis of patients with BVO-ME, including the correlation between retinal structure by OCT and visual acuity. METHODS: Patients with BVO-ME were retrospectively recruited based on clinical records in Kansai Medical University Hospital from June 2012 to March 2022. This study enrolled patients with vision loss who received intravitreal injection of anti-VEGF for BVO-ME. Inclusion criteria were that patients received intravitreal injection of anti-VEGF as their first treatment and were followed for at least 36 months. Exclusion criteria were those patients with ocular disease other than BRVO or who had been previously treated for BVO-ME. Patients were divided into two groups according to BCVA at the final visit: Group A (≥ 0.7) and Group B (< 0.7). RESULTS: Forty-seven eyes from 45 patients were assessed. The mean follow-up period from initial to final visit was 64.38 ± 15.07 (range, 38-100) months. BCVA in Group A (n = 32) was significantly greater than in Group B (n = 15) at all timepoints. The ratio that the number of eyes which the EZ band and the foveal bulge were intact in Group A was higher than in Group B (p = 0.0004 and p = 0.0002, respectively). The ratio that the number of eyes which recurrence SRD was observed by the final visit in Group A was lower than in Group B (p = 0.0485). CONCLUSIONS: The integrity of the EZ band and an intact foveal bulge were significant predictors for visual acuity. In contrast, recurrent SRD led to poor visual acuity in the long term, even if BCVA was good in the short term.

Case of a Giant Conjunctival Melanocytic Nevus.

A 78-year-old female experienced extraocular extension of a giant conjunctival melanocytic mass. The clinical diagnosis was conjunctival malignant melanoma. We performed local excision and histopathological examination. The result of hematoxylin-eosin staining disclosed multiple intralesional mucosal cysts and nevus cell nests with abundant melanin. Immunohistochemical examination revealed expression of S-100, melan-A, and HMB-45 and no expression of Ki-67. Histopathological examination showed no evidence of malignancy. Giant conjunctival melanocytic nevi can be diagnostically confused with conjunctival malignant melanoma.

Time course of collateral vessel formation after retinal vein occlusion visualized by OCTA and elucidation of factors in their formation.

BACKGROUND: It is clinically recognized that collateral vessels can form after retinal vein occlusion (RVO) in some cases and these vessels can lead to spontaneous recovery of the pathological condition. In recent years, optical coherence tomography angiography (OCTA) has become a decisive clinical instrument. Unlike previous angiography tests, OCTA enables the non-invasive visualization of fundus vasculature without the need for administration of a contrast agent. However, it remains to be determined if OCTA depicts the 'true' histological status as several studies have reported artifacts in OCTA imaging. METHODS: We generated a laser-induced mouse RVO model, and evaluated the subsequent formation of collateral vessels in order to understand the mechanisms by which collateral vessels form using OCTA imaging, as well as molecular and histological assessments. RESULTS: We succeeded in visualizing the time course of collateral vessel formation in a mouse RVO model and confirmed the similarity in formation of collateral vessels only within the deep layer of the retina in both human and mouse. We hypothesized that sphingosine 1-phosphate receptor-1 (S1PR1) may play important roles via vascular shear stress linking vein occlusion and collateral vessel formation. Results from OCTA revealed that collateral vessels are increased in response to administration of a S1PR1 agonist in a mouse RVO model. Based on quantitative reverse transcription polymerase chain reaction (qRT-PCR), S1PR1 messenger ribonucleic acid (mRNA) levels in the whole retina peaked 6 h after photocoagulation in this model. Immunohistochemical staining of retinal flat mounts revealed that S1PR1 staining occurred along the laser-occluded blood vessels. CONCLUSION: We observed the temporal process of collateral vessel formation in a mouse RVO model and identified the relationship between S1PR1 and shear stress as one of the factors in collateral vessel formation in RVO.

Long-term results of choroidal neovascularization secondary to angioid streaks.

PURPOSE: To investigate factors contributing to the visual prognosis of choroidal neovascularization (CNV) secondary to angioid streaks (AS) in a long-term follow-up (> 5 years) study. METHODS: Twenty-one patients (32 eyes) affected by CNV secondary to AS were enrolled retrospectively and divided into three groups according to the period of CNV recurrence from the final treatment: group A, no recurrence for more than 12 months; group B, no recurrence for 6-12 months; and group C, no recurrence for < 6 months or ongoing. According to the above classification, we assessed best-corrected visual acuity (BCVA), peau d'orange area, the number of photodynamic treatments and/or intravitreal antiangiogenic drug injections, central choroidal thickness (CCT) and central retinal thickness (CRT) using optical coherence tomography, and enlargement of retinal pigment epithelium (RPE) atrophy. RESULTS: The median follow-up time was 91 months. The median logarithm of the minimum angle of resolution BCVA significantly deteriorated from 0 at baseline to 1 at final follow-up (p < 0.05). Especially, final BCVA in group A showed worst visual outcome despite lowest number of treatments. Peau d'orange areas at baseline were found in 32 eyes (100%). There were no significant differences between initial CRT and final CRT. Median CCT was significantly reduced from 188 µm at baseline to 96 µm at final follow-up (p < 0.05). The median number of treatments was 3.5. Enlargement of RPE atrophy at baseline was found in 31 eyes (96.8%). CONCLUSIONS: Despite the regression of CNV secondary to AS following treatment, the visual prognosis was poor due to the presence of peau d'orange areas, choroidal thinning, and increased RPE atrophy.

Optical coherence tomographic angiography and ultra-widefield indocyanine green angiography of a choroidal macrovessel.

PURPOSE: We evaluated a choroidal macrovessel using optical coherence tomography angiography (OCTA) and indocyanine green angiography (ICGA). OBSERVATIONS: A 79-year-old female presented with blurred vision in both eyes and metamorphopsia of the left eye. Mild cataract was noted in both eyes. Color fundus photography of the left eye revealed a red-orange tortuous vessel originating from the fovea and running in an inferior-temporal direction. Enhanced-depth imaging OCT revealed a large caliber choroidal vascular shadow and ambiguous line of the photoreceptor and retinal pigment epithelium layers. OCTA demonstrated a serpentine-shaped choroidal vessel. This anomalous vessel was seen by early phase ICGA as a rapidly perfused vessel connected to a vortex vein. We diagnosed this anomalous vessel as a choroidal macrovessel. We identified that cataract induced blurred vision in both eyes and choroidal macrovessel induced metamorphopsia in left eye. She was received cataract surgery for both eyes. The degree of metamorphopsia and the choroidal macrovessel of the left eye remains unchanged after a year of follow-up. CONCLUSIONS AND IMPORTANCE: OCTA and ICGA are useful techniques to diagnose choroidal macrovessels.

Developmental and age-related changes to the elastic lamina of Bruch's membrane in mice.

BACKGROUND: Fibrillin-1, tropoelastin, fibulin-5, and latent transforming growth factor beta-binding protein-2 and protein-4 (LTBP-2 and LTBP-4) are essential proteins for the elastic lamina (EL). In this study, we analyzed each of these molecules in the EL of Bruch's membrane (BM) through development and aging. METHODS: C57BL/6 mice (embryonic (E) days E12.5, E15.5, and E18.5; postnatal (P) days P1, P4, and P7 and P3, P6, and P75 weeks of age) were used. To investigate localization, immunohistochemical staining (IH) was performed. Transmission electron microscopy (TEM) was used to evaluate the formation of microfibrils and tropoelastin. mRNA expression was determined by quantitative real-time PCR (qRT-PCR). RESULTS: All five proteins were expressed in the EL of BM by IH except in embryonic mice. TEM results showed that tropoelastin co-stained with microfibrils. Between 3 and 6 weeks of age, microfibrils became longer and thicker. It was difficult to evaluate the EL of BM in senile mice at 75 weeks of age because of abundant deposits which correspond to drusen. mRNA levels of each protein increased dramatically from E15.5 to P1 days and plateaued by P3 weeks as shown by qRT-PCR. CONCLUSIONS: In conclusion, these five proteins are possibly involved in elastic fiber assembly in BM. We define the date of full assembly of the EL of BM as 3 weeks of age in mice.

A new histological evaluation method to detect residual ophthalmic viscosurgical devices for cataract surgery.

PURPOSE: To establish a new evaluation method to quantify residual ophthalmic viscosurgical device (OVD) volume and corneal endothelium adhesion properties for phacoemulsification surgery. METHODS: We compared the performance of four OVDs (Viscoat®, Healon5®, Healon® and DisCoVisc®) using porcine eyes. First, OVDs were mixed with fluorescent-conjugated dextrans to render them visible under the microscope. A corneal side port was opened, followed by a continuous curvilinear capsulorhexis, and a corneal tunnel incision was made. OVDs were injected, then the lens was removed using one-handed phacoemulsification. After this procedure, the anterior segment of the eye was isolated via an equatorial incision and the tissue was immediately frozen in shimmering liquid nitrogen. Sagittal slices (20 µm) were cut with a Cryostat from limbus to limbus. Every tenth slide was imaged using a fluorescent microscope with a CCD camera. We evaluated the percentage of the corneal endothelium covered by each OVD as the OVD adhesion to corneal endothelium ratio (OAE ratio) and the volume of residual OVD in the anterior chamber. RESULTS: Viscoat® showed significantly higher endothelium coverage compared with both Healon® and DisCoVisc®. A statistically larger volume of Healon5® remained in the anterior chamber compared with Healon® and DisCoVisc®. CONCLUSION: The new evaluation methods used here provide precise quantitative analysis of OAE ratio and residual OVD volume. These results show that Viscoat® and Healon5® have a high potential for coating the corneal endothelium during phacoemulsification and aspiration surgery.

Multiple Juvenile Xanthogranuloma of the Eyelids.

Juvenile xanthogranuloma (JXG) is a rare and benign tumor in infants. A solitary lesion on the eyelid has been reported in patients with JXG. We report a 15-year-old boy with multiple involvement of JXG on both eyelids. A mass on the left inner canthus was resected because of disturbance of the visual field and a risk of malignancy in terms of central ulceration in the lesion. The mass was examined by light microscopy. The mass had Touton giant cells with a wreath of nuclei surrounded by foamy histiocytes. No malignancy was observed. The mass showed no recurrence after resection.

Comparison between optical coherence tomography angiography and immunolabeling for evaluation of laser-induced choroidal neovascularization.

This study aimed to investigate the differences between images obtained by optical coherence tomography angiography (OCTA) with those from immunohistochemical labeling of laser-induced choroidal neovascularization (CNV) in a mouse model. CNV was induced by laser photocoagulation (GYC-2000, NIDEK; wavelength 532 nm) in the left eyes of 10 female C57BL/6J mice aged 6 weeks. The laser parameters included a 100-µm spot, 100-ms pulse duration and 200-mW incident power to rupture Bruch's membrane. OCT and OCTA CNV images were obtained using the RS-3000 Advance (NIDEK) 5 days post-laser photocoagulation. After OCTA imaging, the isolated choroid/retinal pigment epithelium complexes were fluorescently labeled with CD31 (an endothelial cell marker), platelet-derived growth factor receptor ß (PDGFRß, a pericyte-like scaffold marker), α-smooth muscle actin (α-SMA) and collagen I. Area measurements of the lesions obtained by enface OCTA were compared with immunolabeled CD31+ CNV lesions in choroid flat-mounts. We also examined structural correlations between the PDGFRß+ pericyte-like scaffold and OCTA images. Laser-induced CNV was clearly detected by enface OCTA, appearing as a hyperflow lesion surrounded by a dark halo. Area measurements of the CNV lesion by immunolabeling were significantly larger than those obtained by enface OCTA (p = 0.006). The CNV lesion beneath the periphery of the pericyte-like scaffold was not clearly visible by enface OCTA due to the dark halo; however, the lesion was detectable as blood flow by cross-sectional OCTA and was also highly labeled by CD31. The periphery of the pericyte-like scaffold appeared to develop into subretinal fibrosis and this region was rich in myofibroblasts. Enface OCTA was unable to detect the entire area of laser-induced CNV in mice, with an undetectable portion located beneath the fibrotic periphery of the pericyte-like scaffold. Due to this OCTA fibrosis artifact, OCTA imaging has limited potential for accurately estimating CNV lesions.

A Case of Adenocarcinoma of the Retinal Pigment Epithelium: An Immunohistochemical and Electron Microscopic Study.

PURPOSE: Retinal pigment epithelium (RPE) adenocarcinoma is a very rare malignant intraocular tumor. Herein we describe the histopathological features of RPE adenocarcinoma. CASE: A 36-year-old male was referred to our clinic because of floaters in his left eye. The initial diagnosis was malignant melanoma of the choroid. We resected the tumor and studied it histopathologically. The tumor tissue was investigated by light microscopy including immunohistochemistry using antibodies against S-100, HMB-45, EMA, and AE-1. Electron microscopic examination was also performed. RESULTS: The tumor arose from the RPE and contained intracytoplasmic vacuoles and abundant melanin pigment. There were no nevoid cells in the choroid. A small part of the tumor cells showed tubular or lobular proliferation and choroidal invasion. Immunohistochemistry revealed positive staining in tumor cells with 4 antibodies. Tight cellular junctions specific to the RPE were confirmed by electron microscopy. The final diagnosis was RPE adenocarcinoma. CONCLUSIONS: Most pigmented intraocular tumors are nevus and malignant melanomas of the choroid. It is easy to misdiagnose a RPE adenocarcinoma as a malignant melanoma of the choroid. An exact differential diagnosis should be determined by immunohistopathological and electron microscopic examination.