Glutathione Trisulfide Prevents Lipopolysaccharide-induced Inflammatory Gene Expression in Retinal Pigment Epithelial Cells

We investigated the effects of glutathione trisulfide (GSSSG) on lipopolysaccharide (LPS)-induced inflammatory gene expression in immortalized ARPE-19, and primary human and mouse retinal pigment epithelial (RPE) cells. Sulfane sulfur molecules were significantly increased in GSSSG-treated ARPE-19 cells. GSSSG prevented the LPS-induced upregulation of interleukin (IL)-1β, IL-6, and C-C motif chemokine ligand 2 (CCL2) in ARPE-19/primary RPE cells. Moreover, GSSSG prevented the activation of the nuclear factor-kappa B p65 subunit, and promoted the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in LPS-treated ARPE-19 cells. ERK1/2 inhibition prevented the GSSSG-mediated inhibition of LPS-induced IL-6 and CCL2 upregulation. Additionally, ERK1/2 activation prevented the upregulation of these genes in the absence of GSSSG. Knockdown of HMOX1 or NRF2, known as anti-oxidative genes, did not affect the activity of GSSSG in the context of LPS stimulation. These findings suggest that GSSSG attenuates LPS-induced inflammatory gene expression via ERK signaling hyperactivation, independently of the NRF2/HMOX1 pathway.

Usefulness of Polarization-sensitive Optical Coherence Tomography-derived Attenuation-coefficient Images to Visualize the Internal Structure of the Filtering Bleb

PURPOSE/AIM OF THE STUDY

Polarization-sensitive anterior-segmental optical coherence tomography (PS-OCT) is useful to evaluate the filtering blebs after trabeculectomy. However, the attenuation phenomenon of OCT signal disturbs the visibility of intra-bleb's structure and distribution of birefringence; a specific parameter of PS-OCT. This study aimed to evaluate the effectiveness of the attenuation-coefficient image of the filtering blebs.

MATERIALS AND METHODS

This study included 25 eyes 6 months after TLE. The attenuation-coefficient image of blebs was calculated from OCT intensity signal information. The contrast level of the image (reflectivity of bleb's surface wall/reflectivity of scleral flap) in both attenuation-coefficient image and intensity image and the height of the bleb's wall were calculated. The improvement extent of contrast was defined as the ratio of contrast (attenuation-coefficient image's contrast/intensity image's contrast). We compared the contrast of attenuation-coefficient image and intensity image and investigated the relationship between improvement extent of contrast and height of bleb's wall.

RESULTS

The contrast of the attenuation-coefficient image (317.7 ± 255.4%) was significantly higher than that of the intensity image (39.1 ± 24.5%) (P < .01) and the improvement extent of contrast was 9.5 ± 4.6 times. Furthermore, there was a positive correlation between the improvement extent of contrast and the height of the bleb's wall (r = 0.44, P = .03).

CONCLUSIONS

The contrast of the image at depth of filtering blebs was improved by attenuation-coefficient image. It is suggested that the attenuation-coefficient image may improve the visibility of the structure and distribution of birefringence in the blebs compared to the intensity image.

Companion Diagnosis for Retinal Neuroprotective Treatment by Real-Time Imaging of Calpain Activation Using a Novel Fluorescent Probe

Calpain activation induces retinal ganglion cell (RGC) death, while calpain inhibition suppresses RGC death, in animal studies. However, the role of calpain in human retinal disease is unclear. This study investigated a new strategy to study the role of calpain based on real-time imaging. We synthesized a novel fluorescent probe for calpain, acetyl-l-leucyl-l-methionine-hydroxymethyl rhodamine green (Ac-LM-HMRG) and used it for real-time imaging of calpain activation. The toxicity of Ac-LM-HMRG was evaluated with a lactate dehydrogenase cytotoxicity assay, retinal sections, and electroretinograms. Here, we performed real-time imaging of calpain activation in a rat model. First, we administered N-methyl-d-aspartate (NMDA) to induce retinal injury. Twenty minutes later, we administered an intravitreal injection of Ac-LM-HMRG. Real-time imaging was then completed with a noninvasive confocal scanning laser ophthalmoscope. The inhibitory effect of SNJ-1945 against calpain activation was also examined with the same real-time imaging method. Ac-LM-HMRG had no toxic effects. The number of Ac-LM-HMRG-positive cells in real-time imaging significantly increased after NMDA injury, and SNJ-1945 significantly lowered the number of Ac-LM-HMRG-positive cells. Real-time imaging with Ac-LM-HMRG was able to quickly quantify the NMDA-induced activation of calpain and the inhibitory effect of SNJ-1945. This technique, used as a companion diagnostic system, may aid research into the development of new neuroprotective therapies.

Serum anti-recoverin antibodies is found in elderly patients with retinitis pigmentosa and cancer

PURPOSE

To screen for anti-recoverin antibodies in elderly patients with retinitis pigmentosa (RP) with or without cancer and cross-sectionally characterize the seropositive patients clinically.

METHODS

Serum from 75 RP patients who had been tested for mutations in a panel of 83 RP genes and 73 normal controls, all aged 50-80 years, were screened for anti-recoverin antibodies by Western blot using recombinant recoverin, retinal lysate from a marmoset and commercial anti-recoverin antibodies as a control.

RESULTS

Three RP patients with typical pigmentary degeneration of the 75 (4.0%) were seropositive for anti-recoverin antibody. Pathogenic mutations were identified in two seropositive RP patients. All three patients had visual impairment since childhood and were diagnosed as RP by the age of 30. The severity of the retinopathy varied greatly among these three patients, ranging in visual acuity from light perception OU to 20/30 OU. Retinitis pigmentosa (RP) patients with a history of cancer were more likely to have anti-recoverin antibodies (3/14; 21.4%) than those without (0/61; 0%; p = 0.005, Fischer exact test). All 73 healthy controls with no history of cancer were also seronegative.

CONCLUSION

Our results show that serum anti-recoverin antibodies can be detected in typical RP patients with identified pathogenic mutations and that a history of cancer may increase the risk of developing anti-recoverin antibodies.

The optic nerve head vasoreactive response to systemic hyperoxia and visual field defect progression in open-angle glaucoma, a pilot study

PURPOSE

To investigate the effect of optic nerve head (ONH) tissue vasoreactivity on glaucoma visual field defect progression.

METHODS

This prospective, longitudinal study comprised 28 eyes of 16 patients with open-angle glaucoma. Baseline data were obtained from oxygen inhalation testing, including laser speckle flowgraphy measurements of tissue-area mean blur rate (MT), which represents ONH tissue blood flow, and the mean percentage change in MT (MT-change). Follow-up data were collected for at least 2 years, including at least 5 reliable visual field tests. The average total deviation (TD) was calculated in each sector of the Garway-Heath map; in this study, superior, central and inferior TD corresponded to inferior, temporal and superior MT or MT-change, respectively. MT and MT-change in three sectors per eye were included as explanatory variables in a multivariable linear mixed-effects model, with TD slope set as the response variable.

RESULTS

At baseline, lower MT and higher diastolic blood pressure were associated with lower MT-change (p < 0.05). Additionally, MT-change significantly contributed to TD slope in the corresponding sectors (β = 0.41, p = 0.01).

CONCLUSIONS

Weaker ONH tissue vasoreactivity to systemic hyperoxia, assessed with laser speckle flowgraphy, was associated with lower baseline ONH tissue blood flow, higher diastolic blood pressure and rapid visual field defect progression. Laser speckle flowgraphy variables during oxygen provocation testing may represent potentially useful predictive biomarkers of glaucoma progression.

A pyruvate dehydrogenase kinase inhibitor prevents retinal cell death and improves energy metabolism in rat retinas after ischemia/reperfusion injury

We aimed to assess the neuroprotective effect of a pyruvate dehydrogenase kinase (PDK) inhibitor, Nov3r after ischemia/reperfusion (IR) injury in rats. IR injury was induced by applying 150 mmHg of intraocular pressure for 50 min. Nov3r was orally administered (100 mg/kg) 3 h before and 24 h after IR injury. TUNEL-positive cells increased and immunoreactive RBPMS-positive cells decreased in the rat retinas after IR injury. Administration of Nov3r significantly ameliorated the increase in TUNEL-positive cells and prevented the RBPMS-positive cell decrease. Similarly, the number of IR-induced Iba1-positive microglial cells was significantly reduced with Nov3r treatment. Among metabolic parameters, IR damage induced the elevation of lactate and pyruvate, and the reduction of ATP. Oral administration of Nov3r ameliorated these changes. Our data suggest that the Nov3r had a retinal neuroprotective effect in IR injury in rats. This finding suggests that the regulation of pyruvate dehydrogenase (PDH) activity has potential therapeutic value by enabling metabolic reprograming in diseases associated with ischemic retinal damage, such as diabetic retinopathy, retinopathy of prematurity, retinal vein occlusion, ischemic optic neuropathy and glaucoma.

Structural Characterization of Glaucoma Patients with Low Ocular Blood Flow

Purpose: There is an unclear relationship between ocular blood flow (OBF) and the structural characteristics of the optic nerve head (ONH) in glaucoma, a multifactorial disease. This study used laser speckle flowgraphy (LSFG) to identify low-OBF glaucoma patients and investigated the ONH in these patients. Materials and Methods: In 533 eyes with glaucoma, we determined confounding factors for LSFG-measured OBF (tissue-area mean blur rate: MT) and corrected MT with a linear mixed-effects model (LMM). Structural ONH data (from fundus stereo photography), OCT data, and clinical characteristics were then compared in patients with corrected MT in the upper and lower quartiles using the LMM. Results: Single regression showed significant correlations between MT and age, spherical equivalent (SE), central corneal thickness (CCT), and a weighted count of retinal ganglion cells (wRGC), but not axial length or systemic blood pressure. Gender also significantly influenced MT; MT was corrected for these correlated factors and also glaucoma type with the LMM. The lower-quartile MT group had a significantly larger cup area and cup-disc area ratio and lower temporal quadrant circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell complex (GCC) than the upper-quartile group. Conclusions: Low-OBF glaucoma patients were characterized by a larger cup-disc ratio, and higher susceptibility to damage in the temporal disc and the macular area.

The association between oxidative stress and corneal hysteresis in patients with glaucoma

Systemic antioxidative status has been implicated in glaucoma pathogenesis. Additionally, corneal hysteresis (CH) may contribute to glaucoma progression. Here, we evaluated the relationship between biological antioxidant potential (BAP) and CH. This study included 103 patients with open-angle glaucoma (OAG). We used a free radical analyzer to measure BAP, and an ocular response analyzer to measure CH and corneal resistance factor (CRF). We evaluated the relationship between systemic oxidative stress and other clinical parameters with Spearman's rank correlation test and a multi-regression analysis. BAP was not correlated to either CH or CRF in the male or female OAG patients. BAP was correlated to both CH and CRF in the female OAG patients older than 57 years (r = 0.51, P = 0.003; r = 0.49, P = 0.004), but uncorrelated in the female OAG patients younger than 57 years. Multiple regression analysis revealed that BAP independently contributed to CH (P = 0.025) and CRF (P = 0.015) in the older female OAG patients. Systemic oxidative stress may significantly affect the viscoelasticity of the cornea in older female OAG patients. Future studies are needed to confirm that low systemic antioxidative status and low corneal hysteresis contribute to glaucoma pathogenesis.

The DNA topoisomerase II inhibitor amsacrine as a novel candidate adjuvant in a model of glaucoma filtration surgery

Treatments for refractory glaucoma include trabeculectomy, in which a filtering bleb is created to reduce aqueous pressure. Mitomycin C (MMC) is often used as an adjuvant to reduce post-trabeculectomy bleb scarring and consequent failure. However, scarring sometimes still occurs. Thus, we searched for more effective trabeculectomy adjuvants with high-throughput screening (HTS) of a library of 1,165 off-patent drug compounds. This revealed that amsacrine (AMSA), a DNA topoisomerase II (TOP2) inhibitor, was the top candidate. Compared to MMC, rabbits that underwent trabeculectomy with 10% AMSA had lower IOP at 42, 56, and 70 days (P < 0.01 at all measurement points) and a higher bleb score at 28, 42, 56, and 70 days (P =  < 0.01, 0.04, 0.04, and < 0.01, respectively). Compared to saline, rabbits that received 1% AMSA also had lower IOP and better bleb score at all time points, without a sharp drop in IOP just after surgery (all P < 0.01). Both effects were milder than MMC at 7 days (P = 0.02 and <0.01, respectively). Thus, this study showed that HTS may help identify new, promising uses for off-patent drugs. Furthermore, trabeculectomy with AMSA at a suitable concentration may improve the prognosis after trabeculectomy compared to MMC.

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.

Potent suppression of HIV-1 cell attachment by Kudzu root extract

There is a constant need to improve antiretrovirals against HIV since therapy is limited by cost, side effects and the emergence of drug resistance. Kudzu is a climbing vine from which the root extract (Pueraria lobata), rich in isoflavones and saponins, has long been used in traditional Chinese medicine for a variety of purposes, from weight loss to alcoholism prevention. Here we show that Kudzu root extract significantly inhibits HIV-1 entry into cell lines, primary human CD4⁺T lymphocytes and macrophages, without cell-associated toxicity. Specifically, Kudzu inhibits the initial attachment of the viral particle to the cell surface, a mechanism that depends on the envelope glycoprotein gp120 but is independent from the HIV-1 cell receptor CD4 and co-receptors CXCR4/CCR5. This activity seems selective to lentiviruses since Kudzu inhibits HIV-2 and simian immunodeficiency virus, but does not interfere with Hepatitis C, Influenza, Zika Brazil and adenovirus infection. Importantly, depending on the dose, Kudzu can act synergistically or additively with the current antiretroviral cocktails against HIV-1 and can block   viruses resistant to the fusion inhibitor Enfuvirtide. Together our results highlight Kudzu's root extract value as a supplement to current antiretroviral therapy against HIV.

Association between mitochondrial DNA damage and ocular blood flow in patients with glaucoma

Background/Aims

We determined the relationship between tissue mean blur rate (MT) and mitochondrial dysfunction, represented by the mitochondrial/nuclear DNA (mtDNA/nDNA) ratio. We also investigated the usefulness of these biomarkers.

Methods

We assessed ocular blood flow in 123 eyes of 123 patients with open-angle glaucoma (OAG) and 37 control eyes of 37 healthy subjects by measuring MT in the optic nerve head with laser speckle flowgraphy. We measured mtDNA and nDNA with PCR, calculated the mtDNA/nDNA ratio and compared this ratio with MT using Spearman’s rank test. We used multiple regression analysis to further investigate the association between MT and glaucoma in the most severe group.

Results

The control and the patients with glaucoma had significant differences in the mtDNA/nDNA ratio, circumpapillary retinal nerve fibre layer thickness and MT. There was no significant relationship between the mtDNA/nDNA ratio and MT in patients with OAG overall or the female patients with OAG, but there was a significant relationship between the mtDNA/nDNA ratio and MT, temporal-MT and superior-MT in male patients with severe OAG (r=−0.46, p=0.03; r=−0.51, p=0.02; r=−0.61, p<0.01, respectively). Furthermore, we found that the mtDNA/nDNA ratio was an independent contributor to temporal-MT and superior-MT in these patients (p<0.01 and p=0.03, respectively).

Conclusion

We found that there was a significant relationship between the mtDNA/nDNA ratio and MT in male patients with severe OAG, suggesting that the mtDNA/nDNA ratio may be a new biomarker in glaucoma and may help research on the vulnerability of these patients to mitochondrial dysfunction.

Ecel1 Knockdown With an AAV2-Mediated CRISPR/Cas9 System Promotes Optic Nerve Damage-Induced RGC Death in the Mouse Retina

Purpose

To assess the therapeutic potential of endothelin-converting enzyme-like 1 (Ecel1) in a mouse model of optic nerve crush.

Methods

Ecel1 expression was evaluated with real time quantitative (qRT)-PCR, Western blotting, and immunohistochemistry in mouse retinas after optic nerve crush. Vinblastine administration to the optic nerve and the intravitreal injection of N-methyl-d-aspartate (NMDA) were used to assess Ecel1 gene expression. Ecel1 was deleted with an adeno-associated viral (AAV) clustered regulatory interspaced short palindromic repeat (CRISPR)/Cas9 system, and retinal ganglion cell (RGC) survival was investigated with retrograde labeling, qRT-PCR, and visual evoked potential.

Results

Optic nerve crush induced Ecel1 expression specifically in the RGCs, peaking on day 4 after optic nerve crush. Ecel1 gene expression was induced by the vinblastine-induced inhibition of axonal flow, but not by NMDA-induced excitotoxicity, even though both are triggers of RGC death. Knockdown of Ecel1 promoted the loss of RGCs after optic nerve crush.

Conclusions

Our data suggest that Ecel1 induction is part of the retinal neuroprotective response to axonal injury in mice. These findings might provide insight into novel therapeutic targets for the attenuation of RGC damage, such as occurs in traumatic optic neuropathy.

Anterior-Segment Optical Coherence Tomography for Predicting Postoperative Outcomes After Trabeculectomy

PURPOSE

To determine whether anterior-segment optical coherence tomography (AS-OCT) can be used to predict post-trabeculectomy bleb outcomes.

MATERIALS AND METHODS

We divided 58 eyes of 47 trabeculectomy patients into success or failure groups based on their status at 12 months after surgery. We then compared various AS-OCT measurement parameters between the two groups at 1 and 2 weeks and 1, 3, 6, and 12 months. We also analyzed the early post-trabeculectomy bleb parameters with multiple logistic regression, stepwise multiple regression, and the receiver operating characteristic (ROC) curve, to evaluate the power of these parameters to predict long-term outcomes.

RESULTS

Intraocular pressure 3 or more months after trabeculectomy was significantly lower in the success group than the failure group (all: P < 0.0016). Cleft volume was significantly higher 6 or more months after trabeculectomy in the success group than the failure group (P = 0.0027 and <0.0016). Reflectivity of the bleb wall was significantly higher in the failure group than the success group at 2 weeks and all later time points (all: P < 0.0016). Reflectivity of the bleb wall at 2 weeks after trabeculectomy was a risk factor for failure, with an odds ratio (OR) for failure of 2.48 (95% confidence interval, 1.31-4.68, increasing per 10 AU). The area under the ROC curve for reflectivity of the bleb wall at 2 weeks after trabeculectomy was 0.775 when the cutoff value was set at 122.8, with sensitivity, specificity, and OR of 78.3%, 80.0%, and 14.4, respectively. A stepwise multiple regression analysis showed that reflectivity of the bleb wall at 2 weeks was an independent factor indicating postoperative bleb survival period (β = -0.39, P = 0.007).

CONCLUSIONS

Reflectivity of the bleb wall, measured by AS-OCT, may be an early post-trabeculectomy predictor of bleb outcome.

Study of termination of postprandial gastric contractions in humans, dogs and Suncus murinus: role of motilin- and ghrelin-induced strong contraction

AIM

Stomach contractions show two types of specific patterns in many species, that is migrating motor contraction (MMC) and postprandial contractions (PPCs), in the fasting and fed states respectively. We found gastric PPCs terminated with migrating strong contractions in humans, dogs and suncus. In this study, we reveal the detailed characteristics and physiological implications of these strong contractions of PPC.

METHODS

Human, suncus and canine gastric contractions were recorded with a motility-monitoring ingestible capsule and a strain-gauge force transducer. The response of motilin and ghrelin and its receptor antagonist on the contractions were studied by using free-moving suncus.

RESULTS

Strong gastric contractions were observed at the end of a PPC in human, dog and suncus models, and we tentatively designated this contraction to be a postprandial giant contraction (PPGC). In the suncus, the PPGC showed the same property as those of a phase III contraction of MMC (PIII-MMC) in the duration, motility index and response to motilin or ghrelin antagonist administration. Ghrelin antagonist administration in the latter half of the PPC (LH-PPC) attenuated gastric contraction prolonged the duration of occurrence of PPGC, as found in PII-MMC.

CONCLUSION

It is thought that the first half of the PPC changed to PII-MMC and then terminated with PIII-MMC, suggesting that PPC consists of a digestive phase (the first half of the PPC) and a discharge phase (LH-PPC) and that LH-PPC is coincident with MMC. In this study, we propose a new approach for the understanding of postprandial contractions.

Preperimetric Glaucoma Prospective Study (PPGPS): Predicting Visual Field Progression With Basal Optic Nerve Head Blood Flow in Normotensive PPG Eyes

Purpose

To investigate the site specificity of visual field changes in eyes with normotensive preperimetric glaucoma (PPG), and to determine factors influencing visual field progression.

Methods

This prospective study comprised 84 eyes of 84 normotensive PPG patients followed for at least 16 months. Optic nerve head (ONH) blood flow was assessed with tissue-area mean blur rate (MBR_T), derived from laser speckle flowgraphy. Total deviation (TD) was measured in each sector of the Garway-Heath map to evaluate the site specificity of visual field loss. Subjects with a TD slope in the first quartile were classified as progressive, and other subjects as nonprogressive. Linear and multiple regression analyses were performed to determine factors affecting visual field progression.

Results

TD in the superior sector significantly decreased in the subjects overall during the follow-up periods (−0.48 ± 1.92 dB/y, P = 0.025). Linear regression analysis showed that basal MBR_T-inferior was correlated significantly with TD-superior slope (r = 0.332, P = 0.002). Furthermore, basal MBR_T was significantly lower in this sector in the progressive than the nonprogressive group (P = 0.010). Multiple linear regression analysis revealed that basal MBR_T-inferior was the only predictive factor for TD-superior slope (β = 0.329, P = 0.005).

Conclusions

These findings suggest that superior-sector visual field progression is most common in normotensive PPG eyes, and that reduced basal ONH blood flow is associated with visual field progression.

Translational Relevance

These findings provide new insight into the involvement of ONH blood flow impairment in glaucoma pathogenesis, and demonstrate the importance of assessing ONH blood flow to determine visual field progression in normotensive PPG.

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.

Preperimetric Glaucoma Prospective Observational Study (PPGPS): Design, baseline characteristics, and therapeutic effect of tafluprost in preperimetric glaucoma eye

Purpose

There is no consensus on the diagnosis or treatment policy for Preperimetric Glaucoma (PPG) because the pathogenesis of PPG is not clear at this time. Preperimetric Glaucoma Prospective Observational Study (PPGPS) is a first multicenter, prospective, observational study to clarify the pathogenesis of PPG. This article indicates study design, patient baseline characteristics, and analysis focused on optic nerve head (ONH) blood flow in PPG, as well as the intraocular pressure (IOP) -lowering effect and ONH blood flow-improving effects of Tafluprost.

Method

In this study, 122 eyes from 122 subjects (mean age: 53.1 ± 14.3) newly diagnosed as PPG were enrolled. The circumpapillary retinal nerve fiber layer thickness (cpRNFLT) was evaluated with optical coherence tomography (OCT). The ONH blood flow was measured with laser speckle flowgraphy. The therapeutic effect of Tafluprost was evaluated at Month 0 (ONH blood flow-improving effect) and Month 4 (IOP-lowering effect).

Results

The untreated IOP, cpRNFLT, and baseline Mean deviation (MD) value was 16.4 ± 2.5 mmHg, 80.4 ± 8.2 μm, and -0.48 ± 1.29 dB, respectively. In the site-specific visual field evaluation using the sector map, there was no appreciable site-specific visual field defect in the eye with PPG. The inferior region of cpRNFLT in 4-quadrant OCT sector analysis and 6 o’clock region in 12-o’clock OCT sector analysis was the highest rate of abnormality in PPG eyes. Topical administration of Tafluprost significantly reduced IOP from 16.4 ± 2.5 mmHg at baseline to 14.5 ± 2.3 mmHg at Month 4 (P < 0.001, paired t-test). In the linear regression analysis, there was a significant relationship between the increase of ONH blood flow and baseline value.

Conclusion

PPGPS is a first prospective study focusing on the pathology of PPG. This study is expected to elucidate the pathology of PPG, with evidence useful for determining a treatment strategy for PPG.

Usefulness of axonal tract-dependent OCT macular sectors for evaluating structural change in normal-tension glaucoma

Purpose

To identify sectors of the optical coherence tomography (OCT) macular map that could be used to effectively assess structural progression in patients with normal-tension glaucoma (NTG).

Methods

This study examined 117 eyes of 117 NTG patients to establish axonal tract-dependent macular sectors, and also examined a separate group of 122 eyes of 81 NTG patients to evaluate the ability of these sectors to reveal glaucoma progression. Longitudinal data, including macular maps from at least 5 OCT examinations performed over at least 2 years, was available for all patients in this group. Circumpapillary retinal nerve fiber layer thickness (cpRNFLT), temporal clockwise sector scans (from 7 to 11 o’clock), macular retinal nerve fiber layer thickness (mRNFLT), and macular ganglion cell layer plus inner plexiform layer thickness (mGCIPLT) were measured with spectral-domain OCT (3D OCT-2000, TOPCON). The axonal tract-dependent macular sectors were identified by calculating Spearman’s rank correlation coefficient for each point on a grid overlaid on the macular map and cpRNFLT in each clockwise scan sector. Trend and event analyses for the slope of progression in each sector and macular map were performed. Visual field progression in the macula was defined by the presence of more than 2 progressive test points in the 16 central test points of the Humphrey field analyzer SITA standard 24–2 program, evaluated with Progressor software.

Results

The slope of progression in the entire macular area was -0.22 ± 0.58 μm/year for mRNFLT and -0.35 ± 0.52 μm/year for mGCIPLT. The fastest-progressing mRNFLT sector (-1.00 ± 0.84 μm/year, p < 0.001) and mGCIPLT sector (-1.16 ± 0.63 μm/year, p < 0.001) progressed significantly faster than the overall macula. Classifying patients according to visual field progression showed that baseline mRNFLT in the inferior hemifield, 7 and 8 o’clock sectors, as well as baseline mGCIPLT in the overall macular map, inferior hemifield, and 8 o’clock sector, were significantly lower in progressors (22 eyes) than non-progressors (100 eyes). There were significant differences in mRNFLT slope in 8 o’clock sector and in the fastest progressing sector in progressors and non-progressors, but mGCIPLT did not differ, even in the fastest-progressing sector. Event analysis showed that progression occurred most frequently in inferior mRNFLT and superior mGCIPLT in this study.

Conclusion

Axonal tract-dependent OCT macular sectors could effectively reveal structural change in patients with NTG. Furthermore, mRNFLT slope was consistent with visual field progression. This method promises to open new avenues for the OCT-based evaluation of glaucoma progression.

A molecular dynamics study of nuclear quantum effect on diffusivity of hydrogen molecule

In this paper, the nuclear quantum effect of the hydrogen molecule on its diffusivity was analyzed using the molecular dynamics (MD) method. The centroid MD (CMD) method was applied to reproduce the time evolution of the molecules. The diffusion coefficient of hydrogen was calculated using the Green-Kubo method over a wide temperature region, and the temperature dependence of the quantum effect of the hydrogen molecule on its diffusivity was addressed. The calculated results were compared with classical MD results based on the principle of corresponding state (PCS). It was confirmed that the difference in the diffusion coefficient calculated in the CMD and classical MD methods was small, and the PCS appears to be satisfied on the temperature dependence of the diffusion coefficient, even though the quantum effect of the hydrogen molecules was taken into account. It was clarified that this result did not suggest that the quantum effect on the diffusivity of the hydrogen molecule was small but that the two changes in the intermolecular interaction of hydrogen due to the quantum effect offset each other. Moreover, it was found that this tendency was related to the temperature dependence of the ratio of the kinetic energy of the quantum fluctuational motion to the classical kinetic energy.

Characteristic Profiles of Inflammatory Cytokines in the Aqueous Humor of Glaucomatous Eyes

PURPOSE

To analyze cytokine profiles of the aqueous humor of eyes with primary open-angle glaucoma (POAG), neovascular glaucoma (NVG), and cataract (as controls).

METHODS

A multiplex bead assay was used to measure concentrations of 27 cytokines in aqueous humor samples from 54 eyes.

RESULTS

Detection rates were as follows: IL-7: NVG higher than POAG; IL-10: POAG lower than cataract or NVG; and GM-CSF: cataract higher than POAG or NVG. Concentrations were as follows: IL-8, IP-10, MCP-1, and MIP-1β: POAG and NVG higher than cataract; IL-9: POAG lower than NVG; IL-12: POAG lower than cataract or NVG; and VEGF: NVG higher than cataract or POAG and POAG lower than cataract. Further analysis showed that IL-8, IP-10, MCP-1, and MIP-1β were correlated with intraocular pressure and age.

CONCLUSIONS

The detection rates and levels of various cytokines had different patterns in POAG and NVG patients, suggesting distinctive alterations in the microenvironment in different types of glaucoma.

Erratum: Estimation of Jones matrix, birefringence and entropy using Cloude-Pottier decomposition in polarization-sensitive optical coherence tomography: erratum

[This corrects the article on p. 3551 in vol. 7, PMID: 27699120.].