Casein kinase-2 inhibition promotes retinal ganglion cell survival after acute intraocular pressure elevation

Intraocular pressure elevation can induce retinal ganglion cell death and is a clinically reversible risk factor for glaucoma, the leading cause of irreversible blindness. We previously demonstrated that casein kinase-2 inhibition can promote retinal ganglion cell survival and axonal regeneration in rats after optic nerve injury. To investigate the underlying mechanism, in the current study we increased the intraocular pressure of adult rats to 75 mmHg for 2 hours and then administered a casein kinase-2 inhibitor (4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole) by intravitreal injection. We found that intravitreal injection of 4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole promoted retinal ganglion cell survival and reduced the number of infiltrating macrophages. Transcriptomic analysis showed that the mitogen activated protein kinase signaling pathway was involved in the response to intraocular pressure elevation but was not modulated by the casein kinase-2 inhibitors. Furthermore, casein kinase-2 inhibition downregulated the expression of genes (Cck, Htrsa, Nef1, Htrlb, Prph, Chat, Slc18a3, Slc5a7, Scn1b, Crybb2, Tsga10ip, and Vstm21) involved in intraocular pressure elevation. Our data indicate that inhibition of casein kinase-2 can enhance retinal ganglion cell survival in rats after acute intraocular pressure elevation via macrophage inactivation.

Visual outcome of various dose of glucocorticoids treatment in nonarteritic anterior ischemic optic neuropathy- a retrospective analysis

BACKGROUND AND PURPOSE

The objective of this investigation was to assess the therapeutic efficacy of distinct glucocorticoid therapy dosages in the management of acute nonarteritic anterior ischemic optic neuropathy (NAION).

MATERIALS AND METHODS

This retrospective, unmasked, and non-randomized study included a total of 85 patients. The patients were categorized into four groups: Group 1 (control) consisted of 15 patients who did not receive glucocorticoids, Group 2 included 16 patients administered with oral prednisone at a dosage of 1 mg/kg/d for 14 days, Group 3 comprised 30 patients who received 250 units of methylprednisolone once daily for 3 days, followed by oral prednisone at a dosage of 1 mg/kg/d for 11 days, and Group 4 encompassed 24 patients who received 500 units of methylprednisolone once daily for 3 days, followed by oral prednisone at a dosage of 1 mg/kg/d for 11 days. The best-corrected visual acuity (BCVA) was assessed at baseline and the final follow-up (> 7 days post-treatment). The changes in visual acuity between baseline and the 7-14 day follow-up, as well as between baseline and the concluding appraisal, were employed as metrics for assessing the extent of visual enhancement.

RESULTS

No significant differences were noted in the final visual outcomes or in the changes between final visual acuity and baseline across the four groups. In Group 1 (control), the best-corrected visual acuity (BCVA) remained unchanged during final follow-ups compared to baseline. Conversely, the intervention groups exhibited statistically significant enhancements in BCVA during final follow-up (p = 0.012, p = 0.03, and p = 0.009 for Group 2, Group 3, and Group 4, respectively) when compared to baseline. During the 7-14 day follow-up, there was a significant difference in the changes between baseline BCVA and follow-up BCVA across the groups (p = 0.035). Go a step further by Bonferroni correction for multiple comparisons, group 4 showed a greater change in vision compared with group1 (p = 0.045).

CONCLUSION

Our study on acute nonarteritic anterior ischemic optic neuropathy (NAION) showed no significant final visual outcome differences. Nevertheless, Groups 2, 3, and 4 demonstrated improved best-corrected visual acuity (BCVA) during the final follow-up. Notably, a 500-unit dose of methylprednisolone resulted in short-term BCVA enhancement. This suggests potential consideration of 500 units of methylprednisolone for short-term NAION vision improvement, despite its limited long-term impact.

Evaluation of Myocilin Variant Protein Structures Modeled by AlphaFold2

Deep neural network-based programs can be applied to protein structure modeling by inputting amino acid sequences. Here, we aimed to evaluate the AlphaFold2-modeled myocilin wild-type and variant protein structures and compare to the experimentally determined protein structures. Molecular dynamic and ligand binding properties of the experimentally determined and AlphaFold2-modeled protein structures were also analyzed. AlphaFold2-modeled myocilin variant protein structures showed high similarities in overall structure to the experimentally determined mutant protein structures, but the orientations and geometries of amino acid side chains were slightly different. The olfactomedin-like domain of the modeled missense variant protein structures showed fewer folding changes than the nonsense variant when compared to the predicted wild-type protein structure. Differences were also observed in molecular dynamics and ligand binding sites between the AlphaFold2-modeled and experimentally determined structures as well as between the wild-type and variant structures. In summary, the folding of the AlphaFold2-modeled MYOC variant protein structures could be similar to that determined by the experiments but with differences in amino acid side chain orientations and geometries. Careful comparisons with experimentally determined structures are needed before the applications of the in silico modeled variant protein structures.

Artificial Intelligence-based database for prediction of protein structure and their alterations in ocular diseases

The aim of the study is to establish an online database for predicting protein structures altered in ocular diseases by Alphafold2 and RoseTTAFold algorithms. Totally, 726 genes of multiple ocular diseases were collected for protein structure prediction. Both Alphafold2 and RoseTTAFold algorithms were built locally using the open-source codebases. A dataset with 48 protein structures from Protein Data Bank (PDB) was adopted for algorithm set-up validation. A website was built to match ocular genes with the corresponding predicted tertiary protein structures for each amino acid sequence. The predicted local distance difference test-Cα (pLDDT) and template modeling (TM) scores of the validation protein structure and the selected ocular genes were evaluated. Molecular dynamics and molecular docking simulations were performed to demonstrate the applications of the predicted structures. For the validation dataset, 70.8% of the predicted protein structures showed pLDDT greater than 90. Compared to the PDB structures, 100% of the AlphaFold2-predicted structures and 97.9% of the RoseTTAFold-predicted structure showed TM score greater than 0.5. Totally, 1329 amino acid sequences of 430 ocular disease-related genes have been predicted, of which 75.9% showed pLDDT greater than 70 for the wildtype sequences and 76.1% for the variant sequences. Small molecule docking and molecular dynamics simulations revealed that the predicted protein structures with higher confidence scores showed similar molecular characteristics with the structures from PDB. We have developed an ocular protein structure database (EyeProdb) for ocular disease, which is released for the public and will facilitate the biological investigations and structure-based drug development for ocular diseases. Database URL:  http://eyeprodb.jsiec.org.

Allergy Test Dosage of Fluorescein Detects Diabetic Retinopathy Changes in Fundus Fluorescein Angiography

BACKGROUND

The aims of this study were to evaluate the feasibility of allergy test dosage of fluorescein sodium (1%) for Diabetic Retinopathy (DR) detection in Fundus Fluorescein Angiography (FFA) examination as compared to the regular dosage (20%).

METHODS

Totally 77 eyes from 42 DR patients were included in this prospective study. Capillary non-perfusion area, neovascularization, diabetic macular edema and microaneurysms were measured by FFA and compared at 1, 5 and 15 min after intravenous injection of 1% or 20% fluorescein sodium.

RESULTS

There was no statistically significant difference in the proportions of capillary non-perfusion area and diabetic macular edema as well as the amount of neovascularization between the 1% and 20% fluorescein sodium groups. Yet, the 1% group had a significantly a smaller number of microaneurysms than the 20% group at 1 min (p < 0.001) and a smaller number of eyes with diabetic macular edema than the 20% group at 5 (p = 0.032) and 15 min (p = 0.015). The images from patients with clear vitreous had better quality than the images from patients with vitreous opacity (all p < 0.05, except comparison on neovascularization at 5 min: p > 0.999). All examined indexes showed high correlations between the 1% and 20% groups (r > 0.8, p < 0.001).

CONCLUSIONS

This study demonstrated that 1% fluorescein sodium could detect the changes of DR comparably to the regular dosage.

Bilateral retinal nerve fiber layer thickness reduction in a 9-year-old myopic boy suffering from unilateral optic neuritis: A case report

BACKGROUND

In this paper, we present a 9-year-old boy who demonstrates a complex interplay between myopia progression, axial length (AL) extension, and retinal nerve fiber layer (RNFL) thickness loss in both eyes. Additionally, concurrent optic neuritis has directly impacted RNFL thickness in his right eye, and its potential indirect influence on RNFL and macular ganglion cell layer (mGCL) thickness in his left eye is also noteworthy.

CASE SUMMARY

A 9-year-old boy with bilateral myopia presented with diminished vision and pain in his right eye due to optic neuritis, while his left eye showed pseudopapilledema. Steroid therapy improved his vision in the right eye, and 16-mo follow-up revealed recovery without recurrence despite myopia progression. Follow-up optical coherence tomography conducted 16 mo later revealed a notable thinning of the RNFL in both eyes, especially along with a reduction in mGCL thickness in the left eye. This intricate interaction between optic neuritis, myopia, and retinal changes underscores the need for comprehensive management, highlighting potential long-term visual implications in young patients.

CONCLUSION

The progression of myopia and AL extension led to the loss of RNFL thickness in both eyes in a 9-year-old boy. Concurrently, optic neuritis directly affected RNFL thickness in his right eye and may indirectly play a role in the thickness of RNFL and mGCL in his left eye.

Optic nerve diseases and regeneration: How far are we from the promised land?

The retinal ganglion cells (RGCs) are the sole output neurons that connect information from the retina to the brain. Optic neuropathies such as glaucoma, trauma, inflammation, ischemia and hereditary optic neuropathy can cause RGC loss and axon damage, and lead to partial or total loss of vision, which is an irreversible process in mammals. The accurate diagnoses of optic neuropathies are crucial for timely treatments to prevent irrevocable RGCs loss. After severe ON damage in optic neuropathies, promoting RGC axon regeneration is vital for restoring vision. Clearance of neuronal debris, decreased intrinsic growth capacity, and the presence of inhibitory factors have been shown to contribute to the failure of post-traumatic CNS regeneration. Here, we review the current understanding of manifestations and treatments of various common optic neuropathies. We also summarise the current known mechanisms of RGC survival and axon regeneration in mammals, including specific intrinsic signalling pathways, key transcription factors, reprogramming genes, inflammation-related regeneration factors, stem cell therapy, and combination therapies. Significant differences in RGC subtypes in survival and regenerative capacity after injury have also been found. Finally, we highlight the developmental states and non-mammalian species that are capable of regenerating RGC axons after injury, and cellular state reprogramming for neural repair.

Retinal transcriptome of neonatal mice after optic nerve injury

BACKGROUND

The axonal growth capacity of retinal ganglion cells decreases dramatically within the first day of birth, and the axonal regeneration after injury in mature mammals is very limited. Here, this study aimed to delineate the transcriptomic changes associated with altered axonal growth capacity and to identify the key genes associated with axonal regeneration by the RNA sequencing (RNA-Seq) analysis.

METHODS

The whole retinas from the mice of embryonic day (E) 20, postnatal day (P) 1 and P3 were collected at 6 hours after optic nerve crush (ONC). Differentially expressed genes (DEGs) for ONC or ages were identified by the RNA-Seq analysis. K-means analysis was conducted for the clustering of DEGs based on expression patterns. Enrichment of functions and signaling pathways analysis were performed based on Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and Gene Set Enrichment analysis (GSEA). Quantitative real time polymerase chain reaction (qRT-PCR) was used to validate the DEGs selected from the RNA-Seq analysis.

RESULTS

In total, 5,408 DEGs were identified for ages, and 2,639 DEGs in neonatal mouse retina after ONC. K-means analysis revealed 7 clusters in age-DEGs and 11 clusters in ONC-DEGs. The GO, KEGG and GSEA pathway analyses identified significantly enrichment of DEGs in the visual perception and phototransduction for the age effect, and the break repair, neuron projection guidance, and immune system pathway for the ONC. PPI analysis identified hub genes in the axon-related gene cluster. The expressions of Mlc1, Zfp296, Atoh7, Ecel1, Creb5, Fosb, and Lcn2, thought to be involved in RGC death and axonal growth were validated by qRT-PCR.

CONCLUSIONS

This study, for the first time, delineated the gene expression changes following ON injury in embryonic and neonatal mice, providing a new resource of age- and injury-driven data on axonal growth capacity.

Acute phase clinical manifestations of patients with Vogt-Koyanagi-Harada disease in Southern China

BACKGROUNDS

To characterize the acute phase clinical manifestations and visual outcomes of the patients with Vogt-Koyanagi Harada (VKH) disease in southern China.

METHODS

In total, 186 patients with acute-onset VKH disease were recruited. The demographic data, clinical signs, ophthalmic examinations, and visual outcomes were analyzed.

RESULTS

Among the 186 VKH patients, 3 were diagnosed as complete VKH, 125 as incomplete VKH, and 58 as probable VKH. All patients visited the hospital within 3 months of onset and complained of decreased vision. For the extraocular manifestations, 121 patients (65%) referred neurological symptoms. Anterior chamber activity was negative in most eyes within an onset of 7 days, which increased slightly with onset beyond 1 week. Exudative retinal detachment (366 eyes, 98%) and optic disc hyperaemia (314 eyes, 84%) were commonly observed at presentation. A typical ancillary examination helped with the diagnosis of VKH. Systemic corticosteroid therapy was prescribed. The logMAR best-corrected visual acuity improved significantly from 0.74 ± 0.54 at baseline to 0.12 ± 0.24 at the 1-year follow-up visit. The recurrence rate was 18% in the follow-up visits. Erythrocyte sedimentation rate and C-reactive protein were significantly correlated to VKH recurrences.

CONCLUSION

Posterior uveitis, followed by mild anterior uveitis, is the typical initial manifestation in the acute phase of Chinese VKH patients. Visual outcome improvement is promising in most patients receiving systemic corticosteroid therapy in the acute phase. Detection of the clinical features at the initial onset of VKH could facilitate early treatment and better vision improvement.

Automatic Detection of Peripheral Retinal Lesions From Ultrawide-Field Fundus Images Using Deep Learning

PURPOSE

To establish a multilabel-based deep learning (DL) algorithm for automatic detection and categorization of clinically significant peripheral retinal lesions using ultrawide-field fundus images.

METHODS

A total of 5958 ultrawide-field fundus images from 3740 patients were randomly split into a training set, validation set, and test set. A multilabel classifier was developed to detect rhegmatogenous retinal detachment, cystic retinal tuft, lattice degeneration, and retinal breaks. Referral decision was automatically generated based on the results of each disease class. t -distributed stochastic neighbor embedding heatmaps were used to visualize the features extracted by the neural networks. Gradient-weighted class activation mapping and guided backpropagation heatmaps were generated to investigate the image locations for decision-making by the DL models. The performance of the classifier(s) was evaluated by sensitivity, specificity, accuracy, F 1 score, area under receiver operating characteristic curve (AUROC) with 95% CI, and area under the precision-recall curve.

RESULTS

In the test set, all categories achieved a sensitivity of 0.836-0.918, a specificity of 0.858-0.989, an accuracy of 0.854-0.977, an F 1 score of 0.400-0.931, an AUROC of 0.9205-0.9882, and an area under the precision-recall curve of 0.6723-0.9745. The referral decisions achieved an AUROC of 0.9758 (95% CI= 0.9648-0.9869). The multilabel classifier had significantly better performance in cystic retinal tuft detection than the binary classifier (AUROC= 0.9781 vs 0.6112, P < 0.001). The model showed comparable performance with human experts.

CONCLUSIONS

This new DL model of a multilabel classifier is capable of automatic, accurate, and early detection of clinically significant peripheral retinal lesions with various sample sizes. It can be applied in peripheral retinal screening in clinics.

Multi-Polymorphism Analysis Reveals Joint Effects in Males With Chronic Central Serous Chorioretinopathy

Purpose

Central serous chorioretinopathy (CSCR) is a leading cause of central vision impairment in the working-age population with male predilection. Knowledge about the genetic basis of CSCR and its male predilection remained limited. This study aimed to evaluate the association patterns of multiple gene variants in chronic CSCR (cCSCR) in Chinese patients.

Methods

This case-control genetic association study included 531 patients with cCSCR and 2383 controls from two independent Chinese cohorts. Nine single-nucleotide polymorphisms (SNPs) of six genes, namely CFH, NR3C2, GATA5, VIPR2, TNFRSF10A, and ARMS2, were genotyped in all subjects. The main outcome measures were the association of individual single-nucleotide polymorphism (SNP) with cCSCR, the sex-stratification effects of individual SNP, and joint effects of different SNPs on cCSCR.

Results

Association results in the two cohorts were consistent with low heterogeneities. In the combined analysis, SNPs CFH rs800292 (odds ratio [OR] = 1.25, P = 0.0020), CFH rs1329428 (OR = 1.23, P = 0.0037), and TNFRSF10A rs13278062 (OR = 1.43, P = 0.0014) were significantly associated with cCSCR. In stratification analysis by sex, 3 SNPs in CFH, rs3753394, rs800292, and rs1329428, were associated with cCSCR in male patients, but not in female patients. Joint analysis revealed that subjects homozygous for the risk alleles of CFH rs800292 and TNFRSF10A rs13278062 had over 4-fold of increased risk of cCSCR when compared with subjects homozygous for the non-risk alleles (OR = 4.06, P = 2.30 × 10-5).

Conclusions

This study revealed main and joint effects of SNPs in CFH and TNFRSF10A on cCSCR, and suggested CFH as a potential genetic factor underlying the male predilection of cCSCR. Further replication in other study populations is needed.

Growth hormone-releasing hormone receptor signaling in experimental ocular inflammation and neuroprotection

Both inflammation and anti-inflammation are involved in the protection of retinal cells. Antagonists of the hypothalamic growth hormone-releasing hormone receptor (GHRHR) have been shown to possess potent anti-inflammatory properties in experimental disease models of various organs, some with systemic complications. Such effects are also found in ocular inflammatory and neurologic injury studies. In experimental models of mice and rats, both growth hormone-releasing hormone receptor agonists and antagonists may alleviate death of ocular neural cells under certain experimental conditions. This review explores the properties of growth hormone-releasing hormone receptor agonists and antagonists that lead to its protection against inflammatory responses induced by extrinsic agents or neurologic injures in ocular animal models.

Automated multidimensional deep learning platform for referable diabetic retinopathy detection: a multicentre, retrospective study

OBJECTIVE

To develop and validate a real-world screening, guideline-based deep learning (DL) system for referable diabetic retinopathy (DR) detection.

DESIGN

This is a multicentre platform development study based on retrospective, cross-sectional data sets. Images were labelled by two-level certificated graders as the ground truth. According to the UK DR screening guideline, a DL model based on colour retinal images with five-dimensional classifiers, namely image quality, retinopathy, maculopathy gradability, maculopathy and photocoagulation, was developed. Referable decisions were generated by integrating the output of all classifiers and reported at the image, eye and patient level. The performance of the DL was compared with DR experts.

SETTING

DR screening programmes from three hospitals and the Lifeline Express Diabetic Retinopathy Screening Program in China.

PARTICIPANTS

83 465 images of 39 836 eyes from 21 716 patients were annotated, of which 53 211 images were used as the development set and 30 254 images were used as the external validation set, split based on centre and period.

MAIN OUTCOMES

Accuracy, F1 score, sensitivity, specificity, area under the receiver operating characteristic curve (AUROC), area under the precision-recall curve (AUPRC), Cohen's unweighted κ and Gwet's AC1 were calculated to evaluate the performance of the DL algorithm.

RESULTS

In the external validation set, the five classifiers achieved an accuracy of 0.915-0.980, F1 score of 0.682-0.966, sensitivity of 0.917-0.978, specificity of 0.907-0.981, AUROC of 0.9639-0.9944 and AUPRC of 0.7504-0.9949. Referable DR at three levels was detected with an accuracy of 0.918-0.967, F1 score of 0.822-0.918, sensitivity of 0.970-0.971, specificity of 0.905-0.967, AUROC of 0.9848-0.9931 and AUPRC of 0.9527-0.9760. With reference to the ground truth, the DL system showed comparable performance (Cohen's κ: 0.86-0.93; Gwet's AC1: 0.89-0.94) with three DR experts (Cohen's κ: 0.89-0.96; Gwet's AC1: 0.91-0.97) in detecting referable lesions.

CONCLUSIONS

The automatic DL system for detection of referable DR based on the UK guideline could achieve high accuracy in multidimensional classifications. It is suitable for large-scale, real-world DR screening.

Diversified Treatment Options of Adult Stem Cells for Optic Neuropathies

Optic neuropathies refer to a group of ocular disorders with abnormalities or dysfunction of the optic nerve, sharing a common pathophysiology of retinal ganglion cell (RGC) death and axonal loss. RGCs, as the retinal neurons in the central nervous system, show limited capacity in regeneration or recovery upon diseases or after injuries. Critically, there is still no effective clinical treatment to cure most types of optic neuropathies. Recently, stem cell therapy was proposed as a potential treatment strategy for optic neuropathies. Adult stem cells, including mesenchymal stem cells and hematopoietic stem cells, have been applied in clinical trials based on their neuroprotective properties. In this article, the applications of adult stem cells on different types of optic neuropathies and the related mechanisms will be reviewed. Research updates on the strategies to enhance the neuroprotective effects of human adult stem cells will be summarized. This review article aims to enlighten the research scientists on the diversified functions of adult stem cells and consideration of adult stem cells as a potential treatment for optic neuropathies in future clinical practices.

Automatic detection of 39 fundus diseases and conditions in retinal photographs using deep neural networks

Retinal fundus diseases can lead to irreversible visual impairment without timely diagnoses and appropriate treatments. Single disease-based deep learning algorithms had been developed for the detection of diabetic retinopathy, age-related macular degeneration, and glaucoma. Here, we developed a deep learning platform (DLP) capable of detecting multiple common referable fundus diseases and conditions (39 classes) by using 249,620 fundus images marked with 275,543 labels from heterogenous sources. Our DLP achieved a frequency-weighted average F1 score of 0.923, sensitivity of 0.978, specificity of 0.996 and area under the receiver operating characteristic curve (AUC) of 0.9984 for multi-label classification in the primary test dataset and reached the average level of retina specialists. External multihospital test, public data test and tele-reading application also showed high efficiency for multiple retinal diseases and conditions detection. These results indicate that our DLP can be applied for retinal fundus disease triage, especially in remote areas around the world.

Agonist of growth hormone-releasing hormone enhances retinal ganglion cell protection induced by macrophages after optic nerve injury

Optic neuropathies are leading causes of irreversible visual impairment and blindness, currently affecting more than 100 million people worldwide. Glaucoma is a group of optic neuropathies attributed to progressive degeneration of retinal ganglion cells (RGCs). We have previously demonstrated an increase in survival of RGCs by the activation of macrophages, whereas the inhibition of macrophages was involved in the alleviation on endotoxin-induced inflammation by antagonist of growth hormone-releasing hormone (GHRH). Herein, we hypothesized that GHRH receptor (GHRH-R) signaling could be involved in the survival of RGCs mediated by inflammation. We found the expression of GHRH-R in RGCs of adult rat retina. After optic nerve crush, subcutaneous application of GHRH agonist MR-409 or antagonist MIA-602 promoted the survival of RGCs. Both the GHRH agonist and antagonist increased the phosphorylation of Akt in the retina, but only agonist MR-409 promoted microglia activation in the retina. The antagonist MIA-602 reduced significantly the expression of inflammation-related genes Il1b, Il6, and Tnf Moreover, agonist MR-409 further enhanced the promotion of RGC survival by lens injury or zymosan-induced macrophage activation, whereas antagonist MIA-602 attenuated the enhancement in RGC survival. Our findings reveal the protective effect of agonistic analogs of GHRH on RGCs in rats after optic nerve injury and its additive effect to macrophage activation, indicating a therapeutic potential of GHRH agonists for the protection of RGCs against optic neuropathies especially in glaucoma.

CXCL5/CXCR2 modulates inflammation-mediated neural repair after optic nerve injury

BACKGROUND

Previous studies reported that mild inflammation promotes retinal ganglion cell (RGC) survival and axonal regeneration after optic nerve (ON) injury with involvement of infiltrating macrophages and neutrophils. Here we aimed to evaluate the involvement and regulation of the main inflammatory chemokine pathway CXCL5/CXCR2 in the inflammation-mediated RGC survival and axonal regeneration in mice after ON injury.

METHODS

The expressions and cellular locations of CXCL5 and CXCR2 were confirmed in mouse retina. Treatment effects of recombinant CXCL5 and CXCR2 antagonist SB225002 were studied in the explant culture and the ON injury model with or without lens injury. The number of RGCs, regenerating axons, and inflammatory cells were determined, and the activation of Akt andSTAT3 signaling pathways were evaluated.

RESULTS

Cxcr2 and Cxcl5 expressions were increased after ON and lens injury. Addition of recombinant CXCL5 promoted RGC survival and neurite outgrowth in retinal explant culture with increase in the number of activated microglia, which was inhibited by SB225002 or clodronate liposomes. Recombinant CXCL5 also alleviated RGC death and promoted axonal regeneration in mice after ON injury, and promoted the lens injury-induced RGC protection with increase in the number of activated CD68⁺ cells. SB225002 inhibited lens injury-induced cell infiltration and activation, and attenuated the promotion effect on RGC survival and axonal regeneration through reduction of lens injury-induced Akt activation.

CONCLUSIONS

CXCL5 promotes RGC survival and axonal regeneration after ON injury and further enhances RGC protection induced by lens injury with CD68⁺ cell activation, which is attenuated by CXCR2 antagonist. CXCL5/CXCR2 could be a potential therapeutic target for RGC survival promotion after ON injury.

Peritoneal macrophages attenuate retinal ganglion cell survival and neurite outgrowth

Inflammation is a critical pathophysiological process that modulates neuronal survival in the central nervous system after disease or injury. However, the effects and mechanisms of macrophage activation on neuronal survival remain unclear. In the present study, we co-cultured adult Fischer rat retinas with primary peritoneal macrophages or zymosan-treated peritoneal macrophages for 7 days. Immunofluorescence analysis revealed that peritoneal macrophages reduced retinal ganglion cell survival and neurite outgrowth in the retinal explant compared with the control group. The addition of zymosan to peritoneal macrophages attenuated the survival and neurite outgrowth of retinal ganglion cells. Conditioned media from peritoneal macrophages also reduced retinal ganglion cell survival and neurite outgrowth. This result suggests that secretions from peritoneal macrophages mediate the inhibitory effects of these macrophages. In addition, increased inflammation- and oxidation-related gene expression may be related to the enhanced retinal ganglion cell degeneration caused by zymosan activation. In summary, this study revealed that primary rat peritoneal macrophages attenuated retinal ganglion cell survival and neurite outgrowth, and that macrophage activation further aggravated retinal ganglion cell degeneration. This study was approved by the Animal Ethics Committee of the Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong Province, China, on March 11, 2014 (approval no. EC20140311(2)-P01).

Automated Explainable Multidimensional Deep Learning Platform of Retinal Images for Retinopathy of Prematurity Screening

Importance

A retinopathy of prematurity (ROP) diagnosis currently relies on indirect ophthalmoscopy assessed by experienced ophthalmologists. A deep learning algorithm based on retinal images may facilitate early detection and timely treatment of ROP to improve visual outcomes.

Objective

To develop a retinal image-based, multidimensional, automated, deep learning platform for ROP screening and validate its performance accuracy.

Design, Setting, and Participants

A total of 14 108 eyes of 8652 preterm infants who received ROP screening from 4 centers from November 4, 2010, to November 14, 2019, were included, and a total of 52 249 retinal images were randomly split into training, validation, and test sets. Four main dimensional independent classifiers were developed, including image quality, any stage of ROP, intraocular hemorrhage, and preplus/plus disease. Referral-warranted ROP was automatically generated by integrating the results of 4 classifiers at the image, eye, and patient levels. DeepSHAP, a method based on DeepLIFT and Shapley values (solution concepts in cooperative game theory), was adopted as the heat map technology to explain the predictions. The performance of the platform was further validated as compared with that of the experienced ROP experts. Data were analyzed from February 12, 2020, to June 24, 2020.

Exposure

A deep learning algorithm.

Main Outcomes and Measures

The performance of each classifier included true negative, false positive, false negative, true positive, F1 score, sensitivity, specificity, receiver operating characteristic, area under curve (AUC), and Cohen unweighted κ.

Results

A total of 14 108 eyes of 8652 preterm infants (mean [SD] gestational age, 32.9 [3.1] weeks; 4818 boys [60.4%] of 7973 with known sex) received ROP screening. The performance of all classifiers achieved an F1 score of 0.718 to 0.981, a sensitivity of 0.918 to 0.982, a specificity of 0.949 to 0.992, and an AUC of 0.983 to 0.998, whereas that of the referral system achieved an F1 score of 0.898 to 0.956, a sensitivity of 0.981 to 0.986, a specificity of 0.939 to 0.974, and an AUC of 0.9901 to 0.9956. Fine-grained and class-discriminative heat maps were generated by DeepSHAP in real time. The platform achieved a Cohen unweighted κ of 0.86 to 0.98 compared with a Cohen κ of 0.93 to 0.98 by the ROP experts.

Conclusions and Relevance

In this diagnostic study, an automated ROP screening platform was able to identify and classify multidimensional pathologic lesions in the retinal images. This platform may be able to assist routine ROP screening in general and children hospitals.

Expression of SARS-CoV-2 receptor ACE2 and TMPRSS2 in human primary conjunctival and pterygium cell lines and in mouse cornea

PURPOSE

To determine the expressions of SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) and type II transmembrane serine protease (TMPRSS2) genes in human and mouse ocular cells and comparison to other tissue cells.

METHODS

Human conjunctiva and primary pterygium tissues were collected from pterygium patients who underwent surgery. The expression of ACE2 and TMPRSS2 genes was determined in human primary conjunctival and pterygium cells, human ocular and other tissue cell lines, mesenchymal stem cells as well as mouse ocular and other tissues by reverse transcription-polymerase chain reaction (RT-PCR) and SYBR green PCR.

RESULTS

RT-PCR analysis showed consistent expression by 2 ACE2 gene primers in 2 out of 3 human conjunctival cells and pterygium cell lines. Expression by 2 TMPRSS2 gene primers could only be found in 1 out of 3 pterygium cell lines, but not in any conjunctival cells. Compared with the lung A549 cells, similar expression was noted in conjunctival and pterygium cells. In addition, mouse cornea had comparable expression of Tmprss2 gene and lower but prominent Ace2 gene expression compared with the lung tissue.

CONCLUSION

Considering the necessity of both ACE2 and TMPRSS2 for SARS-CoV-2 infection, our results suggest that conjunctiva would be less likely to be infected by SARS-CoV-2, whereas pterygium possesses some possibility of SARS-CoV-2 infection. With high and consistent expression of Ace2 and Tmprss2 in cornea, cornea rather than conjunctiva has higher potential to be infected by SARS-CoV-2. Precaution is necessary to prevent possible SARS-CoV-2 infection through ocular surface in clinical practice.

Longitudinal evaluation of immediate inflammatory responses after intravitreal AAV2 injection in rats by optical coherence tomography

Gene therapy has been proposed as a feasible strategy for RGC survival and optic nerve regeneration. Some preclinical and clinical studies revealed intraocular inflammation after intravitreal injection of adeno-associated virus (AAV) by slit-lamp or indirect ophthalmoscope. Here we evaluate the longitudinal profile of immediate inflammatory responses after AAV2 injection in rat retina and vitreous body by optical coherence tomography (OCT). Adult Fischer F344 rats were intravitreally injected once with saline, AAV2 or zymosan. Retinal thickness and cell infiltration were recorded by OCT longitudinally for 2 months and verified by histological analysis. The transduction rate of single intravitreal AAV2 injection was 21.3 ± 4.9% of whole retina, and the transduction efficiency on RGCs was 91.5 ± 2.5% in the transduced area. Significant increase in cell infiltration was observed from Day 1-3 after AAV2 injection, compared to very few infiltrating cells observed in the saline-injected group. The infiltrating cells ceased at Day 5 after intravitreal injection and remained absent at 2 months. The thicknesses of total and inner retina were increased along Day 1-3 after AAV2 injection, but reverted to normal afterwards. The surviving RGCs in the AAV2-injected groups at Day 14 showed no significant difference compared to saline-injected group. In summary, this study revealed the immediate inflammatory responses and retinal edema after intravitreal AAV2 injection in normal rats, without influencing long-term retinal thickness and RGC survival. OCT can be implemented for the time-lapse in vivo evaluation of inflammatory response after AAV-mediated gene therapy through intravitreal injection.

Green Tea Extract Ameliorates Ischemia-Induced Retinal Ganglion Cell Degeneration in Rats

PURPOSE

Oxidative stress induced by reduced blood circulation is a critical pathological damage to retinal ganglion cells (RGCs) in glaucoma. We previously showed that green tea extract (GTE) and its catechin constituents alleviate sodium iodate-induced retinal degeneration in rats. Here, we investigated the therapeutic effect of GTE on ischemia-induced RGC degeneration in rats.

METHODS

RGC degeneration was induced by ischemic reperfusion in adult Fischer F344 rats. Green tea extract (Theaphenon E) was intragastrically administered 4 times within 48 hours after ischemia. RGC survival, pupillary light reflex, expressions of cell apoptosis, oxidative stress, and inflammation-related proteins were studied.

RESULTS

Ischemic reperfusion significantly induced apoptotic RGCs, RGC loss, and larger constricted pupil area compared to the untreated normal rats. Expressions of activated caspase-3 and caspase-8, Sod2, and inflammation-related proteins as well as p38 phosphorylation were significantly upregulated in the ischemia-injured rats. Compared to the saline-fed ischemic rats, significantly higher number of surviving RGCs, less apoptotic RGCs, and smaller constricted pupil area were observed in the GTE-fed ischemic rats. GTE also reduced the increased protein expressions caused by ischemic injury but enhanced the Jak phosphorylation in the retina. Notably, green tea extract did not affect the survival of RGCs in the uninjured normal rats.

CONCLUSIONS

In summary, GTE offers neuroprotection to RGCs under ischemic challenge, suggesting a potential therapeutic strategy for glaucoma and optic neuropathies.

Casein kinase-II inhibition promotes retinal ganglion cell survival and axonal regeneration

Neuron survival is critical for the maintenance of central nervous system physiology upon diseases or injury. We previously demonstrated that the blockage of phosphatidylinositol 3-kinase/Akt and Janus kinase/STAT3 pathways promotes retinal ganglion cell (RGC) survival and axonal regeneration via macrophage activation; yet, the complexity of the inflammatory regulation for neural repair indicates the involvement of additional unresolved signaling pathways. Here we report the effects and underlying mechanism of casein kinase-II (CK2) inhibition on RGC survival and axonal regeneration in rats after optic nerve (ON) injury. Adult rats received intravitreal injection of CK2 inhibitors, TBB (4,5,6,7-Tetrabromo-2-azabenzimidazole) and DMAT (2-Dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole), after ON transection and peripheral nerve (PN) grafting. Intravitreal application of TBB and DAMT effectively suppressed the CK2 phosphorylation activity in the retina, and enhanced RGC survival and axonal regeneration in vivo. Meanwhile, the numbers of infiltrating macrophages were increased. Removal of macrophages by clodronate liposomes significantly abolished the CK2 inhibition-induced RGC survival and axonal regeneration. Clodronate liposomes also weakened the RGC protective effects by TBB and DMAT in vitro. In summary, this study revealed that inhibition of CK2 enhances RGC survival and axonal regeneration via macrophage activation in rats. CK2 could be a therapeutic target for RGC protection after ON injury.

Human Periodontal Ligament-Derived Stem Cells Promote Retinal Ganglion Cell Survival and Axon Regeneration After Optic Nerve Injury

Optic neuropathies are the leading cause of irreversible blindness and visual impairment in the developed countries, affecting more than 80 million people worldwide. While most optic neuropathies have no effective treatment, there is intensive research on retinal ganglion cell (RGC) protection and axon regeneration. We previously demonstrated potential of human periodontal ligament-derived stem cells (PDLSCs) for retinal cell replacement. Here, we report the neuroprotective effect of human PDLSCs to ameliorate RGC degeneration and promote axonal regeneration after optic nerve crush (ONC) injury. Human PDLSCs were intravitreally injected into the vitreous chamber of adult Fischer rats after ONC in vivo as well as cocultured with retinal explants in vitro. Human PDLSCs survived in the vitreous chamber and were maintained on the RGC layer even at 3 weeks after ONC. Immunofluorescence analysis of βIII-tubulin and Gap43 showed that the numbers of surviving RGCs and regenerating axons were significantly increased in the rats with human PDLSC transplantation. In vitro coculture experiments confirmed that PDLSCs enhanced RGC survival and neurite regeneration in retinal explants without inducing inflammatory responses. Direct cell-cell interaction and elevated brain-derived neurotrophic factor secretion, but not promoting endogenous progenitor cell regeneration, were the RGC protective mechanisms of human PDLSCs. In summary, our results revealed the neuroprotective role of human PDLSCs by strongly promoting RGC survival and axonal regeneration both in vivo and in vitro, indicating a therapeutic potential for RGC protection against optic neuropathies. Stem Cells 2018;36:844-855.

AAV-mediated transfer of RhoA shRNA and CNTF promotes retinal ganglion cell survival and axon regeneration

The aim of the present study was to determine whether adeno-associated viral vector (AAV) mediated transfer of ciliary neurotrophic factor (CNTF) and RhoA shRNA has additive effects on promoting the survival and axon regeneration of retinal ganglion cells (RGCs) after optic nerve crush (ONC). Silencing effects of AAV-RhoA shRNA were confirmed by examining neurite outgrowth in PC12 cells, and by quantifying RhoA expression levels with western blotting. Young adult Fischer rats received an intravitreal injection of (i) saline, (ii) AAV green fluorescent protein (GFP), (iii) AAV-CNTF, (iv) AAV-RhoA shRNA, or (v) a combination of both AAV-CNTF and AAV-RhoA shRNA. Two weeks later, the ON was completely crushed. Three weeks after ONC, RGC survival was estimated by counting βIII-tubulin-positive neurons in retinal whole mounts. Axon regeneration was evaluated by counting GAP-43-positive axons in the crushed ON. It was found that AAV-RhoA shRNA decreased RhoA expression levels and promoted neurite outgrowth in vitro. In the ONC model, AAV-RhoA shRNA by itself had only weak beneficial effects on RGC axon regeneration. However, when combined with AAV-CNTF, AAV-RhoA shRNA significantly improved the therapeutic effect of AAV-CNTF on axon regeneration by nearly two fold, even though there was no significant change in RGC viability. In sum, this combination of vectors increases the regenerative response and can lead to more successful therapeutic outcomes following neurotrauma.

Mutations of RagA GTPase in mTORC1 Pathway Are Associated with Autosomal Dominant Cataracts

Cataracts are a significant public health problem with no proven methods for prevention. Discovery of novel disease mechanisms to delineate new therapeutic targets is of importance in cataract prevention and therapy. Herein, we report that mutations in the RagA GTPase (RRAGA), a key regulator of the mechanistic rapamycin complex 1 (mTORC1), are associated with autosomal dominant cataracts. We performed whole exome sequencing in a family with autosomal dominant juvenile-onset cataracts, and identified a novel p.Leu60Arg mutation in RRAGA that co-segregated with the disease, after filtering against the dbSNP database, and at least 123,000 control chromosomes from public and in-house exome databases. In a follow-up direct screening of RRAGA in another 22 families and 142 unrelated patients with congenital or juvenile-onset cataracts, RRAGA was found to be mutated in two unrelated patients (p.Leu60Arg and c.-16G>A respectively). Functional studies in human lens epithelial cells revealed that the RRAGA mutations exerted deleterious effects on mTORC1 signaling, including increased relocation of RRAGA to the lysosomes, up-regulated mTORC1 phosphorylation, down-regulated autophagy, altered cell growth or compromised promoter activity. These data indicate that the RRAGA mutations, associated with autosomal dominant cataracts, play a role in the disease by acting through disruption of mTORC1 signaling.

A group of guanine nucleotide-binding molecules called Rag GTPases are known to play a crucial role in regulation of mTORC1 signaling cascade. In the current study, whole exome sequencing has led to the identification of the RagA GTPase (RRAGA) gene for cataracts and we proceeded to study properties of the RRAGA protein. We captured and sequenced the whole exome for four affected patients from a family with autosomal dominant juvenile-onset posterior cataracts, and found a novel rare mutation in RagA GTPase (RRAGA). To validate this finding, we then sequenced more families and patients, and observed RRAGA mutations in unrelated patients with related phenotypes, suggesting that RRAGA could be mutated in congenital and juvenile-onset cataracts. We further demonstrated supporting evidence that in human lens epithelial cells the RRAGA mutations exerted deleterious effects on relocation of RRAGA to the lysosomes, mTORC1 phosphorylation, autophagy and cell growth. This study gives important new insight into the roles of RRAGA and mTROC1 signaling in the etiology of cataracts.

Adeno-associated virus-mediated expression of growth-associated protein-43 aggravates retinal ganglion cell death in experimental chronic glaucomatous injury

PURPOSE

To examine whether adeno-associated virus (AAV) vector-mediated overexpression of growth-associated protein-43 (GAP-43) has protective or deleterious effects on retinal ganglion cell (RGC) survival in laser-induced chronic intraocular pressure (IOP) elevation injury.

METHODS

Adult Fischer 344 rats received unilateral intravitreal injection of either normal saline, AAV-green fluorescent protein (AAV-GFP), or a bicistronic AAV vector encoding GAP-43 and GFP (AAV-GAP-43). Two weeks later, experimental chronic glaucoma was induced in the injected eyes by scarring the trabecular meshwork with a diode laser. IOP was measured with an impact (rebound) tonometer. Survival of RGCs was estimated after 3 weeks of IOP elevation by quantifying β-III tubulin⁺ neurons in retinal whole mounts. The transfection efficiency of target genes was assessed with direct view of GFP and western blot analysis of GAP-43.

RESULTS

Quantification of β-III tubulin⁺ immunostaining revealed that, compared to uninjured eyes (1,172±80 cells/mm²), 3 weeks of laser-induced IOP elevation led to a 60% decline in RGC survival (496±136 cells/mm²). Transfection with control vector AAV-GFP by itself did not have a significant effect on RGC viability (468±124 cells/mm²). Overexpression of GAP-43 in RGC cell bodies and axons via bicistronic AAV-GAP-43 led to more severe RGC death (260±112 cells/mm²) in IOP elevated eyes, an 80% loss of the total RGC population.

CONCLUSIONS

Overexpression of GAP-43 aggravated RGC death in experimental chronic IOP elevation injury. GAP-43 was upregulated in RGCs regenerating after optic nerve injury. Thus, the finding that this same protein is deleterious to RGC viability after chronic IOP elevation may aid in understanding the mechanisms involved in RGC loss in glaucoma and how best to treat this condition.

Influence of macrophages and lymphocytes on the survival and axon regeneration of injured retinal ganglion cells in rats from different autoimmune backgrounds

The immune response after neural injury influences the survival and regenerative capacity of neurons. In the primary visual pathway, previous studies have described beneficial effects of macrophages and T-cells in promoting neural survival and axonal regeneration in some rat strains. However, the contributions of specific cell populations to these responses have been unclear. In adult Fischer (F344) rats, we confirm prior reports that intravitreal macrophage activation promotes the survival of retinal ganglion cells (RGCs) and greatly enhances axonal regeneration through a peripheral nerve graft. Neonatal thymectomy that results in elimination of T-cell production enhanced RGC survival after axotomy, but diminished the effect of intravitreal macrophage activation on axon regeneration. Thus, in F344 rats, lymphocytes appear to suppress RGC survival but augment the pro-regenerative effects of macrophages. The cytotoxic effect of lymphocytes on RGCs was confirmed in in vitro studies; coculture of retinal explants with lymphocytes led to a 60% reduction in viable RGCs. Similar in vivo results were obtained in Sprague Dawley rats. By comparison, in adult Lewis rats, neither RGC survival nor axonal regeneration was increased after intravitreal macrophage activation. Neonatal thymectomy had only a small beneficial effect on RGC survival, and although Lewis lymphocytes reduced RGC viability in culture, they did so to a lesser extent. Thus, in addition to a complex role of lymphocytes, particularly T-cells, after central nervous system injury, the present results demonstrate that the impact of macrophages is also influenced by genetic background.

PI3K/akt, JAK/STAT and MEK/ERK pathway inhibition protects retinal ganglion cells via different mechanisms after optic nerve injury

Recently we unexpectedly found that PI3K/akt, JAK/STAT and MEK/ERK pathway inhibitors enhanced retinal ganglion cell (RGC) survival after optic nerve (ON) axotomy in adult rat, a phenomenon contradictory to conventional belief that these pathways are pro-survival. In this study we showed that: (i) the RGC protection was pathway inhibition-dependent; (ii) inhibition of PI3K/akt and JAK/STAT, but not MEK/ERK, activated macrophages in the eye, (iii) macrophage removal from the eye using clodronate liposomes significantly impeded PI3K/akt and JAK/STAT inhibition-induced RGC survival and axon regeneration whereas it only slightly affected MEK/ERK inhibition-dependent protection; (iv) in the absence of recruited macrophages in the eye, inhibition of PI3K/akt or JAK/STAT did not influence RGC survival; and (v) strong PI3K/akt, JAK/STAT and MEK/ERK pathway activities were located in RGCs but not macrophages after ON injury. In retinal explants, in which supply of blood-derived macrophages is absent, MEK/ERK inhibition promoted RGC survival whereas PI3K/akt or JAK/STAT inhibition had no effect on RGC viability. However, MEK/ERK inhibition exerted opposite effects on the viability of purified adult RGCs at different concentrations in vitro, suggesting that this pathway may be bifunctional depending on the level of pathway activity. Our data thus demonstrate that inhibition of the PI3K/akt or JAK/STAT pathway activated macrophages to facilitate RGC protection after ON injury whereas the two pathways per se did not modulate RGC viability under the injury conditions (in the absence of the pathway activators). In contrast, the MEK/ERK pathway inhibition protected RGCs via macrophage-independent mechanism(s).

Chemotactic effect of ciliary neurotrophic factor on macrophages in retinal ganglion cell survival and axonal regeneration

PURPOSE

To examine whether ciliary neurotrophic factor (CNTF) has a chemotactic effect on macrophages and whether macrophages are involved in CNTF-induced retinal ganglion cell (RGC) survival and axonal regeneration after optic nerve (ON) injury.

METHODS

Adult Fischer 344 rats received an autologous peripheral nerve graft onto transected ON for injured axons to grow. CNTF was applied intravitreally. When needed, clodronate liposomes were applied intravitreally or intravenously to deplete macrophages in the eye. A chemotaxis microchamber system was used to examine whether CNTF has a chemotactic effect on macrophages in vitro, whereas immunohistochemistry was used to identify the location of macrophages/microglia in the retina. The effects of CNTF on RGC neurite outgrowth and macrophage/microglia proliferation were tested in retinal explants.

RESULTS

Intravitreal CNTF significantly enhanced RGC survival and axonal regeneration as well as the number of macrophages in the eye. Removal of macrophages significantly reduced CNTF-induced RGC survival and axon regeneration. A chemotaxis assay showed a clear chemotactic effect of CNTF on blood-derived but not peritoneal macrophages. Immunohistochemistry revealed that local microglia was located in a region from the nerve fiber layer (NFL) to the inner nuclear layer, whereas blood-derived macrophages were in the NFL. In vitro experiments revealed that CNTF did not enhance neurite outgrowth or macrophage/microglia proliferation in retinal explants.

CONCLUSIONS

CNTF is a chemoattractant but not a proliferation enhancer for blood-derived macrophages, and blood-borne macrophages recruited into the eye by CNTF participate in RGC protection. This finding thus adds an important category to the existing understanding of the biological actions of CNTF.

JAK/STAT pathway mediates retinal ganglion cell survival after acute ocular hypertension but not under normal conditions

Intraocular pressure (IOP) elevation is an important cause of glaucoma. Animal models of ocular hypertension have been widely used to mimic glaucoma to investigate the mechanisms underlying retinal ganglion cell (RGC) death and search for possible cure. The aim of the present study was to examine the role of JAK/STAT pathway in RGC viability in normal condition or after acute IOP elevation. Retinal explants obtained from intact or IOP-elevated eyes were firstly used to examine the effect of the JAK/STAT pathway inhibitors, AG490 and Jak Inhibitor I, on RGC viability in vitro. The role of this signal pathway was further investigated and confirmed in vivo. AG490 and Jak Inhibitor I were applied into the left eye on days 3, 9, and 15 post 2-h IOP elevation at 110mmHg. Fluorescence dye Fluorogold was used to retrogradely label surviving RGCs. Because macrophage recruitment was seen in the IOP-elevated eyes after inhibition of this pathway, clodronate liposomes were used to remove phagocytic cells in the eye and examine the role of JAK/STAT pathway in RGC survival independent of macrophages. Activities and location of JAK/STAT pathway in the retina were examined using Western blotting and immunohistochemistry. We found that inhibition of JAK/STAT pathway did not affect RGC survival in the retinal explants derived from intact eye but caused RGC death in the retinal explants that were derived from IOP-elevated eye. Importantly, the detrimental effect of JAK/STAT pathway inhibition on RGC survival was also observed in vivo following acute IOP elevation, but not in intact eye. In addition, both in vitro and in vivo experiments confirmed a detrimental action of phagocytic cells following acute IOP elevation and the pathway inhibition. Compatible with what were observed in vivo, Western blotting and immunohistochemistry showed that JAK/STAT activities were not present in intact retina, but acute IOP elevation activated JAK/STAT pathway in the retina, in the regions of inner nuclear layer and ganglion cell layer, including RGCs. The IOP elevation-induced JAK/STAT activities were effectively abolished by intravitreal application of AG490. This study thus shows that (1) acute IOP elevation activates JAK/STAT pathway in RGCs, and (2) JAK/STAT pathway mediates RGC survival following IOP elevation but not under normal condition.

A short review of the previous and current epidemiological situation of schistosomiasis in China

Schistosomiasis japonica has long been endemic in the People's Republic of China. In the 1950s, the number of the infected persons was estimated at 10 million; infected snail habitats were estimated at more than 14 billion square metres and infected cattle at 1.2 million. After schistosomiasis control measures were carried out, it was a great success. According to the survey of 1989, infected persons were estimated at 0.95 million; infected snails at 3.47 billion and infected cattle at about 0.1 million. These results compared with those of the 1950s show big reductions in prevalence rates 90.5%, 75.2% and 91.6%, respectively. At present, the disease is a threat in the marshland and lake regions and the high mountainous regions. To maintain the success achieved in effective control and to bring the yet endemic marshland and lake regions and mountainous areas under control are hard and long-term tasks confronting the People's Republic of China.