Reduced Plasma BDNF Levels in Normal Tension Glaucoma Compared to Open Angle Glaucoma.

PRCIS: The study suggests that a low level of systemic BDNF may contribute to the pathogenesis of glaucoma in an IOP-independent manner. AIMS: To evaluate differences in systemic brain-derived neurotrophic factor (BDNF) levels between primary open angle glaucoma (POAG) patients and normal tension glaucoma (NTG) patients. METHODS: This study collected blood samples from 260 NTG patients, 220 age-matched POAG patients, and 120 age-matched cataract patients (as controls). BDNF levels were measured with an antibody-conjugated bead assay system (Luminex). RESULTS: We found that plasma BDNF levels in the NTG group were significantly lower than in the POAG and cataract control groups. There was no significant difference between the POAG and cataract groups. CONCLUSION: This result suggests that a low level of systemic BDNF may contribute to the pathogenesis of glaucoma in an IOP-independent manner.

Glaucoma Diagnosis with Machine Learning Based on Optical Coherence Tomography and Color Fundus Images.

This study aimed to develop a machine learning-based algorithm for glaucoma diagnosis in patients with open-angle glaucoma, based on three-dimensional optical coherence tomography (OCT) data and color fundus images. In this study, 208 glaucomatous and 149 healthy eyes were enrolled, and color fundus images and volumetric OCT data from the optic disc and macular area of these eyes were captured with a spectral-domain OCT (3D OCT-2000, Topcon). Thickness and deviation maps were created with a segmentation algorithm. Transfer learning of convolutional neural network (CNN) was used with the following types of input images: (1) fundus image of optic disc in grayscale format, (2) disc retinal nerve fiber layer (RNFL) thickness map, (3) macular ganglion cell complex (GCC) thickness map, (4) disc RNFL deviation map, and (5) macular GCC deviation map. Data augmentation and dropout were performed to train the CNN. For combining the results from each CNN model, a random forest (RF) was trained to classify the disc fundus images of healthy and glaucomatous eyes using feature vector representation of each input image, removing the second fully connected layer. The area under receiver operating characteristic curve (AUC) of a 10-fold cross validation (CV) was used to evaluate the models. The 10-fold CV AUCs of the CNNs were 0.940 for color fundus images, 0.942 for RNFL thickness maps, 0.944 for macular GCC thickness maps, 0.949 for disc RNFL deviation maps, and 0.952 for macular GCC deviation maps. The RF combining the five separate CNN models improved the 10-fold CV AUC to 0.963. Therefore, the machine learning system described here can accurately differentiate between healthy and glaucomatous subjects based on their extracted images from OCT data and color fundus images. This system should help to improve the diagnostic accuracy in glaucoma.

Pilot study for three-dimensional assessment of laminar pore structure in patients with glaucoma, as measured with swept source optical coherence tomography.

PURPOSE: To develop a method to quantify, based on swept-source optical coherence tomography (OCT), the 3D structure of the laminar pores in patients with glaucoma. METHODS: This retrospective study examined 160 laminar pores from 8 eyes of 8 cases: 4 normal subjects and 4 open-angle glaucoma (OAG) patients. We reconstructed 3D volume data for a 3 x 3 mm disc, using a method similar to OCT angiography, and segmented the structure of the lamina cribrosa. Then, we manually segmented each laminar pore in sequential C-scan images (>90 slices at 2.6-micron intervals) with VCAT5 (RIKEN, Japan). We compared the control and OAG subjects with the Mann-Whitney U test. Differences were considered significant at p < 0.05. RESULTS: We found that the laminar pores of the OAG patients had a significantly smaller average cross-sectional area, smaller 3D volume (adjusted to the average thickness of the lamina cribrosa), and higher true sphericity, and lower principal value (P1, 2, 3) of the 3D structure data (all: p < 0.0001). The topographic distribution of damaged laminar pores was consistent with the damaged area of the macular map. CONCLUSION: We successfully developed a method to quantify the 3D structure of the laminar pores; providing a useful tool to assess lamina cribrosa-associated risk factors for glaucoma. These findings promise to benefit future investigations into the pathomechanisms of glaucoma.

Comparison of Machine-Learning Classification Models for Glaucoma Management.

This study develops an objective machine-learning classification model for classifying glaucomatous optic discs and reveals the classificatory criteria to assist in clinical glaucoma management. In this study, 163 glaucoma eyes were labelled with four optic disc types by three glaucoma specialists and then randomly separated into training and test data. All the images of these eyes were captured using optical coherence tomography and laser speckle flowgraphy to quantify the ocular structure and blood-flow-related parameters. A total of 91 parameters were extracted from each eye along with the patients' background information. Machine-learning classifiers, including the neural network (NN), naïve Bayes (NB), support vector machine (SVM), and gradient boosted decision trees (GBDT), were trained to build the classification models, and a hybrid feature selection method that combines minimum redundancy maximum relevance and genetic-algorithm-based feature selection was applied to find the most valid and relevant features for NN, NB, and SVM. A comparison of the performance of the three machine-learning classification models showed that the NN had the best classification performance with a validated accuracy of 87.8% using only nine ocular parameters. These selected quantified parameters enabled the trained NN to classify glaucomatous optic discs with relatively high performance without requiring color fundus images.

Endophthalmitis associated with Purpureocillium lilacinum during infliximab treatment for surgically induced necrotizing scleritis, successfully treated with 27-gauge vitrectomy.

PURPOSE: To report a case of endophthalmitis associated with Purpureocillium lilacinum (P. lilacinum) during infliximab treatment for surgically induced necrotizing scleritis, successfully treated with 27-gauge vitrectomy. METHODS: A single case report. RESULTS: A 71-year-old man who had undergone immunosuppressive therapy, including infliximab, for surgically induced necrotizing scleritis (SINS) in his left eye complained of visual disturbance and eye pain in the eye. He had a past history of surgery for recurrent pterygium: pterygium excision, amnion transplantation with mitomycin C and limbal transplantation. Visual acuity in the left eye was counting fingers at 30 cm, and intraocular pressure was 3.0 mmHg. Slit-lamp examination revealed the presence of anterior chamber cells (3+), and a B-mode ultrasound scan showed a vitreous opacity. We made a diagnosis of endophthalmitis and performed 27-gauge microincision vitrectomy surgery (27GMIVS) with antibiotic perfusion of ceftazidime, vancomycin and voriconazole. Intraoperative findings included a fungus-like ball-shaped opacity in the vitreous, and a close-to-normal retinal appearance. A vitreous body culture identified the presence of P. lilacinum. After 2 months of antibacterial and antifungal therapy, inflammation decreased and visual acuity recovered to 20/100. CONCLUSIONS: This is the first report of a case of endophthalmitis associated with P. lilacinum during infliximab treatment for SINS. Scleral thinning due to necrotizing scleritis, especially during immunosuppressive therapy, is a risk factor for endophthalmitis. We found that 27GMIVS was a useful strategy for such a challenging clinical situation.

Classification of optic disc shape in glaucoma using machine learning based on quantified ocular parameters.

PURPOSE: This study aimed to develop a machine learning-based algorithm for objective classification of the optic disc in patients with open-angle glaucoma (OAG), using quantitative parameters obtained from ophthalmic examination instruments. METHODS: This study enrolled 163 eyes of 105 OAG patients (age: 62.3 ± 12.6, mean deviation of Humphrey field analyzer: -8.9 ± 7.5 dB). The eyes were classified into Nicolela's 4 optic disc types by 3 glaucoma specialists. Randomly, 114 eyes were selected for training data and 49 for test data. A neural network (NN) was trained with the training data and evaluated with the test data. We used 91 types of quantitative data, including 7 patient background characteristics, 48 quantified OCT (swept-source OCT; DRI OCT Atlantis, Topcon) values, including optic disc topography and circumpapillary retinal nerve fiber layer thickness (cpRNFLT), and 36 blood flow parameters from laser speckle flowgraphy, to build the machine learning classification model. To extract the important features among 91 parameters, minimum redundancy maximum relevance and a genetic feature selection were used. RESULTS: The validated accuracy against test data for the NN was 87.8% (Cohen's Kappa = 0.83). The important features in the NN were horizontal disc angle, spherical equivalent, cup area, age, 6-sector superotemporal cpRNFLT, average cup depth, average nasal rim disc ratio, maximum cup depth, and superior-quadrant cpRNFLT. CONCLUSION: The proposed machine learning system has proved to be good identifiers for different disc types with high accuracy. Additionally, the calculated confidence levels reported here should be very helpful for OAG care.

Evaluation of retinal nerve fiber layer defect using wide-field en-face swept-source OCT images by applying the inner limiting membrane flattening.

PURPOSE: The assessment of retinal nerve fiber layer defects (RNFLDs) is a useful part of glaucoma care. Here, we obtained en-face images of retinal layers below the inner limiting membrane (ILM) with swept source-optical coherence tomography (SS-OCT), and measured RNFLD angle with new software. METHODS: This study included 105 eyes of 105 normal tension glaucoma (NTG) patients (age, 59.8 ± 13.2). Exclusion criteria were best-corrected visual acuity < 0.5, axial length > 28 mm, non-glaucoma ocular disease, and systemic disease affecting the visual field. We obtained 12 x 9 mm 3D volume scans centered on the macula with SS-OCT (DRI OCT-1, Topcon), and from these scans, created 3 averaged en-face images, each comprising 7 horizontal en-face images (total thickness: 18.2 µm). We labeled these averaged images, according to their depth below the ILM, as en-face images 1 (shallowest), 2 (middle) and 3 (deepest). In each image, a circle was drawn centered on the disc, with a radius of half the distance between the centers of the disc and macula. The investigator marked points where the edge of the RNFLD intersected this circle, and RNFLD angle (RNFLDA) was calculated with new software. Finally, we analyzed the association between RNFLDA, cpRNFLT, weighted RGC count (wrgc) and Humphrey field analyzer (HFA)-measured mean deviation (MD) and hemifield total deviation (TD), both overall and in each hemifield. RESULTS: En-face image 2 had the highest interclass reproducibility for measuring RNFLDA (intra-rater intraclass correlation coefficient (ICC): 0.988, inter-rater ICC: 0.962). The correlation coefficients with RNFLDA were: HFA MD, -0.60; superior TD, -0.73; inferior TD, -0.69; overall cpRNFLT, -0.27; superior hemifield cpRNFLT, -0.39; and inferior hemifield cpRNFLT, -0.53 (all p<0.001). CONCLUSIONS: RNFLDA measured in SS-OCT images had high reproducibility and was correlated to glaucoma severity. Our new method may be a valuable future part of glaucoma care.

The Effect of Systemic Hyperoxia on Optic Nerve Head Blood Flow in Primary Open-Angle Glaucoma Patients.

Purpose: To assess the optic nerve head blood flow (ONH BF) response to hyperoxia in glaucoma patients using laser speckle flowgraphy (LSFG), and determine factors influencing vasoreactivity within the ONH. Methods: We performed oxygen provocation testing in 15 eyes of 15 primary open-angle glaucoma (POAG) patients and 15 eyes of 15 age-matched control subjects. During the test, LSFG-derived tissue mean blur rate (MBRT) and clinical variables, including blood pressure, were recorded. We evaluated differences in MBRT alteration during systemic hyperoxia between the groups. Additionally, we calculated the mean % change in MBRT against baseline and determined contributing factors. Results: Despite similar clinical variables during systemic hyperoxia in both groups, the mean % change in MBRT against baseline was significantly lower in the POAG than control subjects (P < 0.0001). Multiple regression analysis revealed that baseline MBRT and systolic blood pressure (SBP) were contributing factors to mean % change in MBRT (ß = 0.44, ß = -0.32, respectively). Additionally, baseline MBRT and SBP were strongly correlated to mean % change in MBRT only in the POAG group (r = 0.83, P < 0.0001; r = -0.60, P = 0.02, respectively). Conclusions: POAG patients had a weaker vasoreactive response to hyperoxia than controls, and this impaired response was associated with lower basal ONH BF and higher SBP. These findings suggest that pre-existing vasoconstriction in the ONH of eyes with glaucoma might reduce the capacity of the vasoconstrictive response to hyperoxia. Alternatively, the pathways that mediate hyperoxia-induced vasoconstriction could be altered in POAG.

Ulcerative keratitis in patients with rheumatoid arthritis in the modern biologic era: a series of eight cases and literature review.

AIM: To assess the prevalence, clinical characteristics, treatment, and outcomes of patients who developed ulcerative keratitis (UK) during the course of rheumatoid arthritis (RA) in the modern biologic era. METHOD: We retrospectively reviewed the medical records of 589 patients with RA who visited our department between April 2003 and October 2014, and identified patients who developed UK. We also obtained data about clinical characteristics of RA and UK, complications, treatment, and both visual and life prognoses of these patients. RESULTS: Among 589 patients with RA, eight patients (1.4%) were diagnosed with UK. The mean age at the onset of RA was 61.0 years, while the mean age at the onset of UK was 73.0 years. Most of the patients were seropositive and had established RA with a relatively low disease activity. Secondary Sjögren's syndrome was observed in two patients. Peripheral UK occurred as a complication of scleritis, while central UK was not associated with scleritis. Although the mean duration of follow-up was only 3.7 years, visual and life prognoses were both tolerable with therapy, including the use of topical and systemic corticosteroids and calcineurin inhibitors, sometimes combined with biologic disease-modifying antirheumatic drugs (DMARDs) and corneal transplantation. CONCLUSION: This retrospective study demonstrated that the prevalence of UK in patients with RA was 1.4%. Immediate combination therapy, including topical and systemic corticosteroids and calcineurin inhibitors, together with biologic DMARDs and corneal transplantation, was effective for treating RA patients who developed UK in the modern biologic era.

OCT-Based Quantification and Classification of Optic Disc Structure in Glaucoma Patients.

PURPOSE: To objectively classify the optic discs of open-angle glaucoma (OAG) patients into Nicolela's four disc types, i.e., focal ischemic (FI), myopic (MY), senile sclerotic (SS), and generalized enlargement (GE), with swept-source optical coherence tomography (SS-OCT). METHODS: This study enrolled 113 eyes of 113 OAG patients (mean age: 62.5 ± 12.6; Humphrey field analyzer-measured mean deviation: -9.4 ± 7.3 dB). Newly developed software was used to quantify a total of 20 optic disc parameters in SS-OCT (DRI OCT-1, TOPCON) images of the optic disc. The most suitable reference plane (RP) above the plane of Bruch's membrane opening was determined by comparing, at various RP heights, the SS-OCT-measured rim parameters and spectral-domain OCT-measured circumpapillary retinal nerve fiber layer thickness (cpRNFLT), with Pearson's correlation analysis. To obtain a discriminant formula for disc type classification, a training group of 72 eyes of 72 OAG patients and a validation group of 60 eyes of 60 OAG patients were set up. RESULTS: Correlation with cpRNFLT differed with disc type and RP height, but overall, a height of 120 µm minimized the influence of disc type. Six parameters were most significant for disc type discrimination: disc angle (horizontal), average cup depth, cup/disc ratio, rim-decentering ratio, average rim/disc ratio (upper and lower nasal). Classifying the validation group with these parameters returned an identification rate of 80.0% and a Cohen's Kappa of 0.73. CONCLUSION: Our new, objective SS-OCT-based method enabled us to classify glaucomatous optic discs with high reproducibility and accuracy.

Characteristic correlations of the structure-function relationship in different glaucomatous disc types.

PURPOSE: To investigate the influence of the optic disc type on the overall and regional correlation between structure and function in open angle glaucoma (OAG). METHODS: We divided 144 eyes of 144 patients with OAG into four groups according to Nicolela et al.'s classification of optic disc type: focal ischemic (FI), myopic glaucomatous (MY), senile sclerotic (SS), and generalized enlargement (GE). We measured the circumpapillary retinal nerve fiber layer thickness (cpRNFLT) with the 3D OCT-2000 and the mean deviation (MD) with the Humphrey Field Analyzer in each group and determined the influence of the disc type on these parameters with the Spearman rank correlation. RESULTS: We found that cpRNFLT and MD were significantly correlated in the MY (r = 0.61, P < 0.001), GE (r = 0.62, P < 0.001), and SS groups (r = 0.52, P = 0.002), but not in the FI group (r = 0.25, P = 0.130). The region of the optic disc with the highest correlation coefficient between structure and function differed according to the disc type. CONCLUSIONS: The correlation between cpRNFLT and MD varied according to the optic disc morphology in OAG. This suggests that different disc types have characteristic regional variations in the correlation between structure and function. The disc type should therefore be considered in investigations of the correlation between structure and function in glaucoma.

Mechanisms of cadmium-induced chronotoxicity in mice.

Biological defense factors show diurnal variations in their expression levels or activities. These variations can induce the different sensitivity to external toxicants of a day. We reported earlier that mice showed clear diurnal variation of cadmium (Cd)-induced toxicity, i.e., chronotoxicity. In this report, we investigated additional new evidences for the cadmium (Cd)-induced chronotoxicity, and considered the mechanisms contributed to this chronotoxicity. Male C57BL/6J mice were injected with CdCl2 (6.4 mg/kg, one shot) intraperitoneally at 6 different time points of a day (zeitgeber time (ZT); ZT2, ZT6, ZT10, ZT14, ZT18 or ZT22) followed by monitoring the mortality until 14 days after the injection. We observed extreme difference in survival numbers: surprisingly, all mice died at ZT2 injection while all mice survived at ZT18 injection. Moreover, in non-lethal dose of Cd (4.5 mg/kg), the values of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) used as indexes of hepatotoxicity markedly increased at ZT6 injection while mostly unchanged at ZT18 injection. To consider the mechanisms of this extreme diurnal variation, we examined biochemical studies and concluded that the diurnal variation was not caused by the differences in hepatic Cd level, basal hepatic metallothionein (MT) level, and induction level or induction speed of hepatic MT. We suggested that one of the candidate determination factors was glutathione. We believe that the "chronotoxicology" for metal toxicity may be classic, yet new viewpoint in modern toxicology field.

Influence of injection timing on severity of cadmium-induced testicular toxicity in mice.

Cadmium (Cd) is one of the endocrine disrupter and is a well-known testicular toxicant. Recently, we reported that Cd-induced mortality was markedly different by injection timing. In this report, we investigated whether severity of testicular toxicity was affected by injection timing of Cd. C57BL/6J mice (male, 7 w) were received single intraperitoneal injection of CdCl(2) (4.5 mg/kg) at zeitgeber time 6 (ZT6) or ZT18; these injection timings showed highest (ZT6) or lowest (ZT18) mortality in our previous study (Miura, 2012). After one week of the injection, several parameters for testicular toxicity such as epididymal sperm motility and numbers of sperm head both in cauda epididymidis and testis were measured. At ZT6 injection group, all parameters examined were significantly reduced compared to the control group. However, very interestingly, no significant changes were observed at ZT18 injection group. We obtained similar results by another experiment in which mice were received single subcutaneous injection of CdCl(2) (4 or 6 mg/kg) followed by measuring the parameters ten days after the injection. This diurnal variation was not contradictory to the result of the lethal toxicity which we showed earlier. Therefore, our results indicate that the testicular toxicity of Cd is also influenced by the injection timing.

Apolipophorin-III expression and low density lipophorin formation during embryonic development of the silkworm, Bombyx mori.

We examined the expression of apolipophorin-III (apoLp-III) during embryonic development of the silkworm Bombyx mori. ApoLp-III mRNA was first expressed 24h after oviposition, which corresponds to the time of germ band formation. The amount of apoLp-III in the eggs increased from day 2, peaked on day 4, and then gradually decreased until hatching (on day 9.5). ApoLp-III was apparently synthesized during early embryogenesis, as radioactive amino acids were incorporated into newly synthesized apoLp-III in three-day-old eggs. Moreover, radioactive apoLp-III was found only in the embryo and not in the extraembryonic tissue. KBr density gradient ultracentrifugation of egg homogenates showed that apoLp-III was associated with low-density lipophorin (LDLp). These results suggest that LDLp is required for the delivery of lipids for organogenesis during embryogenesis.

A CD36-related transmembrane protein is coordinated with an intracellular lipid-binding protein in selective carotenoid transport for cocoon coloration.

The transport pathway of specific dietary carotenoids from the midgut lumen to the silk gland in the silkworm, Bombyx mori, is a model system for selective carotenoid transport because several genetic mutants with defects in parts of this pathway have been identified that manifest altered cocoon pigmentation. In the wild-type silkworm, which has both genes, Yellow blood (Y) and Yellow cocoon (C), lutein is transferred selectively from the hemolymph lipoprotein to the silk gland cells where it is accumulated into the cocoon. The Y gene encodes an intracellular carotenoid-binding protein (CBP) containing a lipid-binding domain known as the steroidogenic acute regulatory protein-related lipid transfer domain. Positional cloning and transgenic rescue experiments revealed that the C gene encodes Cameo2, a transmembrane protein gene belonging to the CD36 family genes, some of which, such as the mammalian SR-BI and the fruit fly ninaD, are reported as lipoprotein receptors or implicated in carotenoid transport for visual system. In C mutant larvae, Cameo2 expression was strongly repressed in the silk gland in a specific manner, resulting in colorless silk glands and white cocoons. The developmental profile of Cameo2 expression, CBP expression, and lutein pigmentation in the silk gland of the yellow cocoon strain were correlated. We hypothesize that selective delivery of lutein to specific tissue requires the combination of two components: 1) CBP as a carotenoid transporter in cytosol and 2) Cameo2 as a transmembrane receptor on the surface of the cells.

Purification and expression analysis of imaginal disc growth factor in the silkworm, Bombyx mori.

In the present study, we purified and sequenced a homolog of the Drosophila imaginal disc growth factor (IDGF) from the hemolymph of Bombyx mori (BmIDGF). Antibodies against BmIDGF were produced and subsequently used in immunoblotting analyses. The immunoblotting analyses demonstrated an extremely high level of BmIDGF in the hemolymph throughout the period of rapid growth of the organs of B. mori. The results of RT-PCR showed that BmIDGF was predominantly expressed in fat bodies. Real-time RT-PCR revealed that BmIDGF transcripts in fat bodies were highly expressed during the feeding stage but significantly suppressed during the molting, wandering, and pupal stages. Starvation brought about a significant decline of BmIDGF mRNAs in the fat bodies and BmIDGF proteins in the hemolymph. After re-feeding, the BmIDGF transcripts in fat bodies and BmIDGF proteins in the hemolymph increased again. In addition, an immunocytochemical study revealed BmIDGF proteins on the surface of wing discs. The present findings suggest that the level of BmIDGF in the hemolymph was modulated by the fat body in response to nutritional conditions and that BmIDGF was transported to target organs through the hemolymph.