Masahiro Tonari

Blocking Endothelin-B Receptors Rescues Retinal Ganglion Cells from Optic Nerve Injury through Suppression of Neuroinflammation

PURPOSE The endothelins (ETs) cause reactive astrogliosis, which involves neuroinflammation and neurodegeneration in the central nervous system. The purpose of this study was to determine whether blocking the ET signals will protect retinal ganglion cells (RGCs) from optic nerve injury. METHODS We studied the effect of pretreatment with BQ-123, an antagonist of ETA receptors, and BQ-788, an antagonist of ETB receptors, on the survival of RGCs after the optic nerve of rats was crushed. We also performed immunohistological evaluations and real-time PCR of the crushed site to determine the expressions of the ET-1, CD68, GFAP, TNF-α, and iNOS genes in the neuroinflammation of the optic nerves. RESULTS The mRNA levels of the ETB receptors were upregulated (5.6-fold) on day 7 after crushing the optic nerves. Cells expressing ETB receptors were recruited mainly to the crushed site where the immunoreactivity to GFAP was weak. These cells were also immuunoreactive to ETs and CD68, a constitutive marker of microglia/macrophages. In the adjacent areas, immunoreactivity to GFAP was intense. Crushing the optic nerve increased the mRNA levels of ET-1 (4.5-fold), CD68 (87.5-fold), GFAP (2-fold), TNF-α (480-fold), and iNOS (6-fold) on day 7. Pretreatment with BQ-788 significantly suppressed the upregulation of these genes and loss of RGCs on day 7, whereas BQ-123 failed to protect the RGCs. CONCLUSIONS These results suggest that the microglia/macrophages recruited to the crushed site are the possible cellular sources of the ETs, which caused reciprocal activation of astrocytes. Blocking the ETB receptors by BQ-788 rescued RGCs, most likely by attenuating neuroinflammatory events.

Systemic Simvastatin Rescues Retinal Ganglion Cells from Optic Nerve Injury Possibly through Suppression of Astroglial NF-κB Activation

Neuroinflammation is involved in the death of retinal ganglion cells (RGCs) after optic nerve injury. The purpose of this study was to determine whether systemic simvastatin can suppress neuroinflammation in the optic nerve and rescue RGCs after the optic nerve is crushed. Simvastatin or its vehicle was given through an osmotic minipump beginning one week prior to the crushing. Immunohistochemistry and real-time PCR were used to determine the degree of neuroinflammation on day 3 after the crushing. The density of RGCs was determined in Tuj-1 stained retinal flat mounts on day 7. The effect of simvastain on the TNF-α-induced NF-κB activation was determined in cultured optic nerve astrocytes. On day 3, CD68-positive cells, most likely microglia/macrophages, were accumulated at the crushed site. Phosphorylated NF-κB was detected in some astrocytes at the border of the lesion where the immunoreactivity to MCP-1 was intensified. There was an increase in the mRNA levels of the CD68 (11.4-fold), MCP-1 (22.6-fold), ET-1 (2.3-fold), GFAP (1.6-fold), TNF-α (7.0-fold), and iNOS (14.8-fold) genes on day 3. Systemic simvastatin significantly reduced these changes. The mean ± SD number of RGCs was 1816.3±232.6/mm2 (n = 6) in the sham controls which was significantly reduced to 831.4±202.5/mm2 (n = 9) on day 7 after the optic nerve was crushed. This reduction was significantly suppressed to 1169.2±201.3/mm2 (P = 0.01, Scheffe; n = 9) after systemic simvastatin. Simvastatin (1.0 µM) significantly reduced the TNF-α-induced NF-κB activation in cultured optic nerve astrocytes. We conclude that systemic simvastatin can reduce the death of RGCs induced by crushing the optic nerve possibly by suppressing astroglial NF-κB activation.

Orbital apex syndrome associated with herpes zoster ophthalmicus.

We report our findings for a patient with orbital apex syndrome associated with herpes zoster ophthalmicus. Our patient was initially admitted to a neighborhood hospital because of nausea and loss of appetite of 10 days’ duration. The day after hospitalization, she developed skin vesicles along the first division of the trigeminal nerve, with severe lid swelling and conjunctival injection. On suspicion of meningoencephalitis caused by varicella zoster virus, antiviral therapy with vidarabine and betamethasone was started. Seventeen days later, complete ptosis and ophthalmoplegia developed in the right eye. The light reflex in the right eye was absent and anisocoria was present, with the right pupil larger than the left. Fat-suppressed enhanced T1-weighted magnetic resonance images showed high intensity areas in the muscle cone, cavernous sinus, and orbital optic nerve sheath. Our patient was diagnosed with orbital apex syndrome, and because of skin vesicles in the first division of the trigeminal nerve, the orbital apex syndrome was considered to be caused by herpes zoster ophthalmicus. After the patient was transferred to our hospital, prednisolone 60 mg and vidarabine antiviral therapy was started, and fever and headaches disappeared five days later. The ophthalmoplegia and optic neuritis, but not the anisocoria, gradually resolved during tapering of oral therapy. From the clinical findings and course, the cause of the orbital apex syndrome was most likely invasion of the orbital apex and cavernous sinus by the herpes virus through the trigeminal nerve ganglia.

Central retinal artery occlusion resembling Purtscher-like retinopathy

This paper reports three cases of central retinal artery occlusion (CRAO) with Purtscher-like retinopathy and good recovery of visual function. The three cases of CRAO had similar fundus changes, ie, cotton wool patches surrounding the optic disc and whitening of the retina surrounding the fovea with a cherry red spot. Fluorescein angiography showed a delay of arm-to-retina circulation time and a partial defect of choroid circulation. Although the three cases were treated by different regimens of steroid pulse therapy and antiplatelet therapy, visual function recovered well and all disturbances of the retinal and choroid circulations resolved. Although eyes with a CRAO normally have a poor visual prognosis, our three cases responded well to the treatments and recovered good visual function. Thus, cases showing fundus changes similar to our three cases may have a pathogenesis different from that of a complete CRAO.

Changes in expression of aquaporin-4 and aquaporin-9 in optic nerve after crushing in rats.

The purpose of this study was to determine the temporal and spatial changes in the expression of AQP4 and AQP9 in the optic nerve after it is crushed. The left optic nerves of rats were either crushed (crushed group) or sham operated (sham group), and they were excised before, and at 1, 2, 4, 7, and 14 days later. Four optic nerves were pooled for each time point in both groups. The expression of AQP4 and AQP9 was determined by western blot analyses. Immunohistochemistry was used to determine the spatial expression of AQP4, AQP9, and GFAP in the optic nerve. Optic nerve edema was determined by measuring the water content in the optic nerve. The barrier function of the optic nerve vessels was determined by the extravasated Evans blue dye on days 7 and 14. The results showed that the expression of AQP4 was increased on day 1 but the level was significantly lower than that in the sham group on days 4 and 7 (P<0.05). In contrast, the expression of AQP9 gradually increased, and the level was significantly higher than that in the sham group on days 7 and 14 (P<0.05, Tukey-Kramer). The down-regulation of AQP4 was associated with crush-induced optic nerve edema, and the water content of the nerve was significantly increased by 4.3% in the crushed optic nerve from that of the untouched fellow nerve on day 7. The expression of AQP4 and GFAP was reduced at the crushed site where AQP4-negative and AQP9-positive astrocytes were present. The barrier function was impaired at the crushed site on days 7 and 14, restrictedly where AQP4-negative and AQP9-positive astrocytes were present. The presence of AQP9-positive astrocytes at the crushed site may counteract the metabolic damage but this change did not fully compensate for the barrier function defect.

A case of eosinophilic chronic rhinosinusitis associated with optic neuropathy

We report a case of eosinophilic chronic rhinosinusitis (ECRS) associated with optic neuropathy. The visual acuity in the right eye was suddenly reduced to no light perception on awakening in the morning. Fundus examination of both eyes on the same day showed no remarkable changes. Emergency computed tomography showed pan-sinusitis bilaterally and a partial defect of the sphenoid bone on the right side. From the clinical findings, the case was diagnosed as optic neuropathy associated with chronic sinusitis. Endoscopic sinus surgery (ESS) was performed on the same day, and all of the major sinuses were found to be filled with highly viscous fluid. Part of the optic canal had a defect probably due to inflammatory invasion from the adjacent sphenoid bone. Steroid therapy was started immediately postoperatively. Histopathological examination of excised polyps showed that numerous eosinophils had invaded the polyps but no hyphae were present. The patient reported that he had bronchial asthma and had had nasal polypectomy. Six months after the ESS and steroid therapy, the patient had a recurrence of the sinusitis. At that time, laboratory examination showed an elevation of total IgE and eosinophil numbers. From the clinical findings and course, this case was diagnosed as ECRS accompanied by optic neuropathy. Although ECRS rarely has ocular complications, the inflammation can spread and the optic nerve can be affected.

Ocular findings in Japanese children with Down syndrome: the course of visual acuity and refraction, and systemic and ocular anomalies

Purpose To investigate the age-related development of refractive errors and changes of visual acuity (VA), and the systemic and ocular anomalies in Japanese children and young adults with Down syndrome (DS). Design Retrospective cohort study. Subjects and methods This study involved 222 Japanese children and young adults with DS (age range: 3 months to 19 years) seen at the Department of Ophthalmology, Shiga Medical Center for Children, Shiga, Japan. The subjects were divided into the following six age groups: 1) infant (age 0 to <4 years), 2) preschool (age 4 to <7 years), 3) lower primary-school grades (age 7 to <10 years), 4) upper primary-school grades (age 10 to <13 years), 5) junior high school (age 13 to <16 years), and 6) late teen/young adults (age 16 to <20 years). Through examination of the subjects’ medical charts, we investigated the development and changes of refractive errors and VA, best-corrected VA (BCVA), and systemic and ocular anomalies. Results For vision testing, Teller Acuity Cards™ (Bernell Corporation) were used for the infants, and the Landolt ring was used for the school-age children. VA was found to develop with age. Mean BCVA was 0.19±0.17 logarithm of the minimum angle of resolution (mean age: 11.3±3.2 years). Mean of refractive errors was hyperopia in the infant (2.2±2.4 diopters [D] OD, 2.4±2.5D OS), yet became myopia to the junior high school (−0.3±4.4D OD, −0.2±4.4D OS). Conclusion Our findings revealed that in children and in late-teen and young-adult subjects with DS, VA slowly develops and that refractive errors requiring correction exist and are difficult to examine.

C-reactive protein may be useful to differentiate idiopathic orbital inflammation and orbital cellulitis in cases with acute eyelid erythema and edema

Purpose Idiopathic orbital inflammation (IOI) and orbital cellulitis can present similar clinical features, and the diagnoses of these two disorders are sometimes confused. The purpose of the present study was to determine whether or not inflammatory markers in the blood can be useful to differentiate between IOI and orbital cellulitis in cases with acute eyelid erythema and edema. Subjects and methods In this retrospective single-institute study, we reviewed the medical records spanning the past 10 years at the Department of Ophthalmology, Osaka Medical College Hospital, Takatsuki, Osaka, Japan, and found 45 cases, with patients >15 years of age, with presumed IOI. Their blood samples were obtained within 5 days after the onset of IOI. Of those cases, 15 patients (10 males, 5 females, mean age of 56.9 years; range 38–76 years) presented acute eyelid erythema and edema, and were initially misdiagnosed as orbital cellulitis. Thus, inflammatory markers in the blood (ie, white blood cells [WBCs] and C-reactive protein [CRP]) of those 15 patients were analyzed with 17 patients (10 males, 7 females) having orbital cellulitis. The receiver operating characteristic curve analysis was performed to determine the optimal cut-off values. Results The mean ± standard error (SE) levels of the WBC were 6.80±0.70×103/μL in the IOI patients, and 8.54±0.91×103/μL in the orbital cellulitis patients, and no significant differences were observed (P=0.15, Student’s t-test). However, the mean ± SE levels of CRP were 1.04±0.43 mg/dL in the IOI patients, yet were significantly increased to 4.65±1.21 mg/dL in the orbital cellulitis patients (P=0.01, Student’s t-test). The area under the curve value was 0.80 and the optimal cut-off value was 0.43 for orbital cellulitis, with sensitivity and specificity being 82% and 73%, respectively. Conclusion The findings of this study indicate that CRP may be useful in distinguishing patients with idiopathic orbital inflammation from those with orbital cellulitis.

A Case of Fundus Oculi Albinoticus Diagnosed as Angelman Syndrome by Genetic Testing

Purpose: To report a case of fundus oculi albinoticus diagnosed as Angelman syndrome (AS) via genetic testing. Case Report: This study reports on a 4-year-old boy. Since he had been having respiratory disturbance since birth, he underwent a complete physical examination to investigate the cause. The results indicated that he had various brain congenital abnormalities, such as a thin corpus callosum, as well as hydronephrosis, an atrial septal defect, and skin similar to patients with fundus oculi albinoticus. Examination revealed bilateral fundus oculi albinoticus, mild iridic hypopigmentation, optic atrophy, and poor visual tracking. Genetic testing revealed a deletion in the Prader-Willi syndrome/AS region on chromosome 15, and together with the results of methylation analysis, his condition was diagnosed as AS. Follow-up examinations revealed no change in the fundus oculi albinoticus and optic atrophy, nor did they indicate poor visual tracking. Conclusions: When fundus oculi albinoticus and optic atrophy are observed in patients with multiple malformations, AS should be considered as a differential diagnosis.

A Case of Childhood-Onset Giant Cell Tumor that Caused Optic Nerve Atrophy in Both Eyes

Purpose: The purpose of this study was to report the case of a female patient who had a giant cell tumor in the paranasal sinus during childhood, and while undergoing multiple resection surgeries experienced optic atrophy in both eyes. Case Presentation: This study involved a 35-year-old woman who was previously diagnosed with a giant cell tumor of the paranasal sinus bone at age 13. A CT scan revealed a large tumor extending from the sphenoid sinus to the ethmoid sinus. At age 14, a tumor resection was performed in conjunction with radiation therapy. However, after resection and radiation therapy there were repeated recurrences, and additional resections were performed. Ophthalmically, there was marked optical atrophy in both eyes, and Goldmann visual field perimetry revealed that only the arcuate peripheral area remained on the nasal side of the right eye, and that there were dark spots in the paracentral area of the left eye. Conclusions: In this case, a large giant cell tumor occurred in the sphenoid sinus and ethmoid sinus during childhood, and it is thought that optic atrophy was caused by compressive optic neuropathy. The sphenoid sinus and ethmoid sinuses are anatomically close to the optic nerve, and when a tumor grows larger at this site it can easily put pressure on the optic nerve. Therefore, early detection and treatment are important.