Involvement of autotaxin in the pathophysiology of elevated intraocular pressure in Posner-Schlossman syndrome

Lipid mediators in glaucoma: Unraveling their diverse roles and untapped therapeutic potential

Glaucoma is a complex neurodegenerative disease characterized by optic nerve damage and visual field loss, and remains a leading cause of irreversible blindness. Elevated intraocular pressure (IOP) is a critical risk factor that requires effective management. Emerging research underscores dual roles of bioactive lipid mediators in both IOP regulation, and the modulation of neurodegeneration and neuroinflammation in glaucoma. Bioactive lipids, encompassing eicosanoids, specialized pro-resolving mediators (SPMs), sphingolipids, and endocannabinoids, have emerged as crucial players in these processes, orchestrating inflammation and diverse effects on aqueous humor dynamics and tissue remodeling. Perturbations in these lipid mediators contribute to retinal ganglion cell loss, vascular dysfunction, oxidative stress, and neuroinflammation. Glaucoma management primarily targets IOP reduction via pharmacological agents and surgical interventions, with prostaglandin analogues at the forefront. Intriguingly, additional lipid mediators offer promise in attenuating inflammation and providing neuroprotection. Here we explore these pathways to shed light on their intricate roles, and to unveil novel therapeutic avenues for glaucoma management.

Effects of Brimonidine, Omidenepag Isopropyl, and Ripasudil Ophthalmic Solutions to Protect against H2O2-Induced Oxidative Stress in Human Trabecular Meshwork Cells

PURPOSE

We investigated whether hydrogen peroxide (H2O2)-induced oxidative stress causes human trabecular meshwork (HTM) cell dysfunction observed in open angle glaucoma (OAG) in vitro, and the effects of topical glaucoma medications on oxidative stress in HTM cells.

METHODS

We used commercially available ophthalmic solutions of brimonidine, omidenepag isopropyl, and ripasudil in the study. HTM cells were exposed to H2O2 for 1 h, with or without glaucoma medications. We assessed cell viability and senescence via WST-1 and senescence-associated-β-galactosidase (SA-β-Gal) activity assays. After exposure to H2O2 and glaucoma medications, we evaluated changes in markers of fibrosis and stress by using real-time quantitative polymerase chain reaction (qPCR) to measure the mRNA levels of collagen type I alpha 1 chain (COL1A1), fibronectin, alpha-smooth muscle actin (α-SMA), matrix metalloproteinase-2 (MMP-2), endoplasmic reticulum stress markers of C/EBP homologous protein (CHOP), 78-kDa glucose-regulated protein (GRP78), and splicing X-box binding protein-1 (sXBP-1).

RESULTS

HTM cell viability decreased and SA-β-Gal activity increased significantly after exposure to H2O2. Treatment with three ophthalmic solutions attenuated these changes. Real-time qPCR revealed that H2O2 upregulated the mRNA levels of COL1A1, fibronectin, α-SMA, CHOP, GRP78, and sXBP-1, whereas it downregulated MMP-2 mRNA expression significantly. Brimonidine suppressed the upregulation of stress markers CHOP and GRP78. Additionally, omidenepag isopropyl and ripasudil decreased the upregulation of COL1A1 and sXBP-1. Furthermore, ripasudil significantly suppressed fibrotic markers fibronectin and α-SMA, compared with the other two medications.

CONCLUSION

In vitro, H2O2 treatment of HTM cells induced characteristic changes of OAG, such as fibrosis changes and the upregulation of stress markers. These glaucomatous changes were attenuated by additional treatments with brimonidine, omidenepag isopropyl, and ripasudil ophthalmic solutions.

Clinical Differences between Posner-Schlossman Syndrome Patients with Intermittent Intraocular Pressure Elevation and Glaucomatous Damage

INTRODUCTION

Although there is abundant evidence that Posner-Schlossman syndrome (PSS) can lead to secondary glaucoma, data on the clinical differences between PSS patients with secondary glaucoma and those with intermittent intraocular pressure (IOP) elevation are sparse.

METHODS

This retrospective observational study included 52 patients (52 eyes) diagnosed with PSS and admitted to Zhongnan Hospital of Wuhan University between January 2019 and February 2022. Demographic characteristics and clinical features were gathered from admission records. Patients were divided into two groups: 27 cases with intermittent IOP elevation (group A) and 25 cases with secondary glaucoma (group B and C). Of the secondary glaucoma cases, 18 were further divided into the topical IOP-lowering medications group (group B) and 7 into the glaucoma surgery group (group C). Clinical characteristics of different groups were compared.

RESULTS

Compared to the intermittent IOP elevation group, PSS patients with secondary glaucoma had a longer course of disease, a higher incidence of iris depigmentation, lower best corrected visual acuity, lower endothelial cell density, and higher interferon-γ (IFN-γ) concentration and cytomegalovirus (CMV) deoxyribonucleic acid (DNA) copy number in the aqueous humor (all p < 0.05). Group C presented a higher CMV DNA copy number in the aqueous humor than groups A and B (p < 0.05). Compound trabeculectomy proved effective in group C, with a functional filter bleb and well-controlled IOP without disease progression after 1 year of follow-up.

CONCLUSION

Distinctive characteristics existed between PSS patients with secondary glaucoma and those with intermittent IOP elevation. Compound trabeculectomy appears to be an effective treatment option when IOP cannot be controlled through topical medications.

Risk factors associated with corneal endothelial cell density in Posner-Schlossman syndrome

PURPOSE

To investigate the risk factors related to corneal endothelial cell density (ECD) in patients with Posner-Schlossman syndrome (PSS).

PATIENTS AND METHODS

It was an observational retrospective study. We reviewed the medical records of patients with PSS who attended the ophthalmology department at Wuhan University Zhongnan Hospital from January 2019 to December 2021. 42 eyes of 42 patients with PSS were included in the study. Demographic characteristics and clinical manifestations were recorded. The clinical characteristics of PSS patients with reduced ECD were compared with PSS patients with normal ECD. Simple and multiple linear regression analyses were carried out to identify the risk factors for ECD in PSS.

RESULTS

The ECD-lowered group had a longer disease duration (P = 0.000), higher rate of occurrence of corneal edema (P = 0.039), higher cytomegalovirus (CMV) deoxyribonucleic acid (DNA) copy number (P = 0.044), higher interleukin-10 (IL-10) level in the aqueous humor (P = 0.044), and thinner average retinal nerve fiber layer (RNFL) thickness (P = 0.016) than the control group. The results of multiple linear regression analysis indicated that disease duration (β =  - 0.287, P = 0.024) and level of IL-10 in the aqueous humor (β =  - 0.408, P = 0.001) were significantly negatively associated with ECD, while average RNFL thickness (β = 0.330, P =  0.007) was significantly positively related to ECD in PSS.

CONCLUSION

A longer disease duration, higher degree of glaucomatous damage and elevated level of IL-10 in the aqueous humor were associated with reduced ECD in PSS.

Is fat the future for saving sight? Bioactive lipids and their impact on glaucoma

Glaucoma is characterized by a continuous loss of retinal ganglion cells. The cause of glaucoma is associated with an increase in intraocular pressure (IOP), but the underlying pathophysiology is diverse and, in most cases, unknown. There is an indisputable unmet need to identify new pathways involved in glaucoma pathogenesis. Increasing evidence suggests that bioactive lipids may be critical in the development and progression of glaucoma. Preclinical and clinical bioactive lipid targets exist and are being developed. In this review, we aim to shed light on the potential of bioactive lipids for the prevention, diagnosis, prognosis, and treatment of glaucoma by asking the question "is fat the future for saving sight".

Ripasudil Eyedrops Ameliorated Bullous Keratopathy Complicated with Cytomegalovirus Corneal Endotheliitis: A Case Report

PURPOSE

We describe a case of bullous keratopathy complicated with cytomegalovirus (CMV) corneal endotheliitis that was successfully treated with ripasudil eye drops.

METHODS

A retrospective case report.

RESULTS

A 65-year-old female patient diagnosed with CMV-associated anterior uveitis in the right eye was referred to us when anterior uveitis recurred with bullous keratopathy. Initial best-corrected visual acuity (BCVA) was 0.4 (decimal visual acuity). Her condition did not improve with anti-CMV treatment, and BCVA decreased to 0.07. At this point, intraocular pressure (IOP) was 20 mmHg, and ripasudil eye drops were started for IOP control. After 1 month, not only had IOP decreased to 14 mm Hg but the condition of the corneal edema had also improved. The central corneal thickness decreased to a normal level, and the BCVA recovered to 0.8.

CONCLUSION

Ripasudil eye drops not only lower IOP in patients with CMV corneal endotheliitis but may also have the potential to treat bullous keratopathy.

Fibrotic Response of Human Trabecular Meshwork Cells to Transforming Growth Factor-Beta 3 and Autotaxin in Aqueous Humor

This study examines the potential role of transforming growth factor-beta 3 (TGF-β3) on the fibrotic response of cultured human trabecular meshwork (HTM) cells. The relationships and trans-signaling interactions between TGF-β3 and autotaxin (ATX) in HTM cells were also examined. The levels of TGF-β and ATX in the aqueous humor (AH) of patients were measured by an immunoenzymetric assay. The TGF-β3-induced expression of the fibrogenic markers, fibronectin, collagen type I alpha 1 chain, and alpha-smooth muscle actin, and ATX were examined by quantitative real-time PCR, Western blotting, and immunocytochemistry, and the trans-signaling regulatory effect of TGF-β3 on ATX expression was also evaluated. In HTM cells, the significant upregulation of ATX was induced by TGF-β3 at a concentration of 0.1 ng/mL, corresponding to the physiological concentration in the AH of patients with exfoliative glaucoma (XFG). However, higher concentrations of TGF-β3 significantly suppressed ATX expression. TGF-β3 regulated ATX transcription and signaling in HTM cells, inducing the upregulation of fibrogenic proteins in a dose-dependent manner. Trans-signaling of TGF-β3 regulated ATX transcription, protein expression, and signaling, and was thereby suggested to induce fibrosis of the trabecular meshwork. Modulation of trans-signaling between TGF-β3 and ATX may be key to elucidate the pathology of XFG, and for the development of novel treatment modalities.

Role of Autotaxin in High Glucose-Induced Human ARPE-19 Cells

Autotaxin (ATX) is an enzymatic with lysophospholipase D (lysoPLD) activity. We investigated the role of ATX in high glucose (HG)-induced human retinal pigment epithelial (ARPE-19) cells to explore the pathogenesis of diabetic retinopathy (DR). We performed a quantitative real-time polymerase chain reaction, Western blotting, immunocytochemistry, enzyme-linked immunosorbent assay, cell permeability assay, and transepithelial electrical resistance measurement in HG-induced ARPE-19 cells and compared their results with those of normal glucose and osmotic pressure controls. ATX expression and its lysoPLD activity, barrier function, and expression of vascular endothelial growth factor receptors VEGFR-1 and VEGFR-2 were downregulated, while fibrotic responses, cytoskeletal reorganization, and transforming growth factor-β expression were upregulated, in the HG group. Our results suggest that HG induces intracellular ATX downregulation, barrier dysfunction, and fibrosis, which are involved in early DR and can be targeted for DR treatment.

Autotaxin May Have Lysophosphatidic Acid-Unrelated Effects on Three-Dimension (3D) Cultured Human Trabecular Meshwork (HTM) Cells

PURPOSE

The objective of the current study was to evaluate the effects of the autotaxin (ATX)-lysophosphatidic acid (LPA) signaling axis on the human trabecular meshwork (HTM) in two-dimensional (2D) and three-dimensional (3D) cultures of HTM cells.

METHODS

The effects were characterized by transendothelial electrical resistance (TEER) and FITC-dextran permeability (2D), measurements of size and stiffness (3D), and the expression of several genes, including extracellular matrix (ECM) molecules, their modulators, and endoplasmic reticulum (ER) stress-related factors.

RESULTS

A one-day exposure to 200 nM LPA induced significant down-sizing effects of the 3D HTM spheroids, and these effects were enhanced slightly on longer exposure. The TEER and FITC-dextran permeability data indicate that LPA induced an increase in the barrier function of the 2D HTM monolayers. A one-day exposure to a 2 mg/L solution of ATX also resulted in a significant decrease in the sizes of the 3D HTM spheroids, and an increase in stiffness was also observed. The gene expression of several ECMs, their regulators and ER-stress related factors by the 3D HTM spheroids were altered by both ATX and LPA, but in different manners.

CONCLUSIONS

The findings presented herein suggest that ATX may have additional roles in the human TM, in addition to the ATX-LPA signaling axis.

RhoA/ROCK-YAP/TAZ Axis Regulates the Fibrotic Activity in Dexamethasone-Treated Human Trabecular Meshwork Cells

High intraocular pressure (IOP) is a major risk factor for glaucoma, a leading cause of irreversible blindness. Abnormal fibrotic activity in the human trabecular meshwork (HTM) cells is considered to be partly responsible for the increased resistance of aqueous humor outflow and IOP. This study aimed to identify the fibrotic pathways using integrated bioinformatics and further elucidate their mechanism of regulating fibrotic activity in dexamethasone (DEX)-treated HTM cells. Microarray datasets from the GEO database were obtained and analyzed by GEO2R. Bioinformatics analyses, including GO and KEGG analyses, were performed to explore biological functions and signaling pathways of differentially expressed genes (DEGs). The fibrotic pathways and targets were determined by western blot, RT-qPCR, or immunofluorescence staining. The cellular elastic modulus was measured using an atomic force microscope. A total of 204 DEGs, partly enriched in fibrotic activity (collagen-containing ECM, fibroblast activation) and Rap1, Ras, TGF-β, and Hippo pathways, were identified. Experimental results showed that DEX induced fibrotic activity and regulated the expression of RhoA/ROCK in HTM cells. Similarly, the constitutively active RhoA (RhoAG14V) also promoted the fibrotic activity of HTM cells. Mechanistically, RhoAG14V induced the expression and nuclear translocation of YAP/TAZ to produce CTGF. Moreover, inhibition of ROCK or YAP decreased the expression of Collagen I and α-SMA proteins induced by DEX or RhoAG14V in HTM cells. In conclusion, these results indicate that RhoA/ROCK-YAP/TAZ axis plays a crucial role in regulating the fibrotic activity of DEX-treated HTM cells.

PDGFRα Enhanced Infection of Breast Cancer Cells with Human Cytomegalovirus but Infection of Fibroblasts Increased Prometastatic Inflammation Involving Lysophosphatidate Signaling

Human cytomegalovirus (HCMV) infects 40-70% of adults in developed countries. HCMV proteins and DNA are detected in tumors and metastases, suggesting an association with increased invasion. We investigated HCMV infection in human breast cancer cell lines compared to fibroblasts, a component of tumors, and the role of platelet-derived growth factor receptor-α (PDGFRα). HCMV productively infected HEL299 fibroblasts and, to a lesser extent, Hs578T breast cancer cells. Infection of another triple-negative cell line, MDA-MB-231, and also MCF-7 cells, was extremely low. These disparate infection rates correlated with expression of PDGFRA, which facilitates HCMV uptake. Increasing PDGFRA expression in T-47D breast cancer and BCPAP thyroid cancer cells markedly increased HCMV infection. Conversely, HCMV infection decreased PDGFRA expression, potentially attenuating signaling through this receptor. HCMV infection of fibroblasts promoted the secretion of proinflammatory factors, whereas an overall decreased secretion of inflammatory factors was observed in infected Hs578T cells. We conclude that HCMV infection in tumors will preferentially target tumor-associated fibroblasts and breast cancer cells expressing PDGFRα. HCMV infection in the tumor microenvironment, rather than cancer cells, will increase the inflammatory milieu that could enhance metastasis involving lysophosphatidate.

mTOR inhibitors potentially reduce TGF-β2-induced fibrogenic changes in trabecular meshwork cells

We examined the effects of mTOR inhibitors on the fibrotic response induced by transforming growth factor-beta2 (TGF-β2) in cultured human trabecular meshwork (hTM) cells. TGF-β2-induced expression of fibronectin, collagen type I, alpha 1 chain (COL1A1), and alpha-smooth muscle actin (αSMA) in hTM cells was examined in the presence or absence of mTOR inhibitors using quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry. The migration rates of hTM cells were examined in the presence of TGF-β2 with or without mTOR inhibitors. An in vitro study showed that the expression of fibronectin, COL1A1, and αSMA was upregulated by TGF-β2 treatment of hTM cells; such upregulation was significantly suppressed by mTOR inhibitors. The inhibitors significantly reduced the migration rate of TGF-β2-stimulated hTM cells. mTOR inhibitors may usefully reduce the fibrotic response of hTM cells and we may have to explore if it is also effective in in vivo model.

Crosstalk between transforming growth factor β-2 and Autotaxin in trabecular meshwork and different subtypes of glaucoma

BACKGROUND

Elevated transforming growth factor (TGF)-β2 in aqueous humor (AH) has been suggested to contribute to trabecular meshwork (TM) fibrosis and intraocular pressure (IOP) regulation in primary open-angle glaucoma (POAG), but TGF-β2 is downregulated in secondary open-angle glaucoma (SOAG). Because autotaxin (ATX) is upregulated in SOAG, we investigated the relationships and trans-signaling interactions of these mediators.

METHODS

The level of ATX in AH was determined using a two-site immunoenzymetric assay, and TGF-β levels were measured using the Bio-Plex Pro TGF-β Assay. RNA scope was used to assess the expression of ATX and TGF-β2 in human's eye specimen. And in vitro studies were performed using hTM cells to explore if trans-signaling of TGF-β2 regulates ATX expressions.

RESULTS

TGF-β2/ATX ratio was significantly high in AH of control or POAG compared with SOAG, and negatively correlated with IOP. RNA scope revelated positive expressions of both TGF-β2 and ATX in ciliary body (CB) and TM in control, but ATX expressions was significantly enhanced in SOAG. In hTM cells, ATX expressions were regulated by TGF-β2 with concentration-dependent manner. In counter, ATX also induced TGF-β1, TGF-β2 and TGFBI upregulations and activation of the Smad-sensitive promoter, as well as upregulation of fibrotic markers, and these upregulation was significantly suppressed by both TGF-β and ATX inhibition.

CONCLUSIONS

Trans-signaling of TGF-β2 regulates ATX expressions and thereby induced upregulations of TGF-βs or fibrosis of hTM. TGF-β2 trans-signaling potently regulate ATX transcription and signaling in hTM cells, which may reflect different profile of these mediators in glaucoma subtypes. Trial Registration This prospective observational study was approved by the Institutional Review Board of the University of Tokyo and was registered with the University Hospital Medical Information Network Clinical Trials Registry of Japan (ID: UMIN000027137). All study procedures conformed to the Declaration of Helsinki. Written informed consent was obtained from each patient.

The lysophosphatidic acid axis in fibrosis: Implications for glaucoma

Glaucoma is a common progressive optic neuropathy that results in visual field defects and can lead to irreversible blindness. The pathophysiology of glaucoma involves dysregulated extracellular matrix remodelling in both the trabecular meshwork in the anterior chamber and in the lamina cribrosa of the optic nerve head. Fibrosis in these regions leads to raised intraocular pressure and retinal ganglion cell degeneration, respectively. Lysophosphatidic acid (LPA) is a bioactive lipid mediator which acts via six G-protein coupled receptors on the cell surface to activate intracellular pathways that promote cell proliferation, transcription and survival. LPA signalling has been implicated in both normal wound healing and pathological fibrosis. LPA enhances fibroblast proliferation, migration and contraction, and induces expression of pro-fibrotic mediators such as connective tissue growth factor. The LPA axis plays a major role in diseases such as idiopathic pulmonary fibrosis, where it has been identified as an important pharmacological target. In glaucoma, LPA is present in high levels in the aqueous humour, and its signalling has been found to increase resistance to aqueous humour outflow through altered trabecular meshwork cellular contraction and extracellular matrix deposition. LPA signalling may, therefore, also represent an attractive target for treatment of glaucoma. In this review we wish to describe the role of LPA and its related proteins in tissue fibrosis and glaucoma.

Lysophosphatidic Acid and IL-6 Trans-signaling Interact via YAP/TAZ and STAT3 Signaling Pathways in Human Trabecular Meshwork Cells

Purpose

Lysophosphatidic acid (LPA) and soluble interleukin-6 receptor (sIL6R) are elevated in primary open angle glaucoma (POAG). LPA and IL6 modulate in response to biomechanical stimuli and converge on similar fibrotic phenotypes. Thus, we determined whether LPA and IL6 trans-signaling (IL6/sIL6R) interact via Yes-associated protein (YAP)/Transcriptional coactivator with a PDZ-binding motif (TAZ) or Signal transducer and activator of transcription 3 (STAT3) pathways in human trabecular meshwork (hTM) cells.

Methods

Confluent primary hTM cells were serum starved for 24 hours, and treated with vehicle, LPA (20 µM), IL6 (100 ng/mL)/sIL6R (200 ng/mL), or both (LPA + IL6/sIL6R) for 24 hours, with or without a YAP inhibitor (verteporfin; 2 µM) or STAT3 inhibitor (2 µM). Expression of key receptors and ligands, signaling mediators, actomyosin machinery, cell contractility, and extracellular matrix (ECM) targets of both signaling pathways was determined by immunocytochemistry, RT-qPCR, and Western blotting.

Results

LPA and IL6 trans-signaling coupling overexpressed/activated receptors and ligands, glycoprotein-130, IL6, and autotaxin; signaling mediators, YAP, TAZ, Pan-TEAD, and phosphorylated STAT3 (pSTAT3); actomyosin and contractile machinery components, myosin light chain 2 (MLC2), phosphorylated MLC2, rho-associated protein kinase 1, filamentous actin, and α-smooth muscle actin; and fibrotic ECM proteins, collagen I and IV, fibronectin, laminin, cysteine-rich angiogenic inducer 61, and connective tissue growth factor in hTM cells; mostly beyond LPA or IL6 trans-signaling alone. Verteporfin inhibited YAP, TAZ, and pSTAT3, with concomitant abrogation of aforementioned fibrotic targets; the STAT3 inhibitor was only partially effective.

Conclusions

These data suggest synergistic crosstalk between LPA and IL6 trans-signaling, mediated by YAP, TAZ, and pSTAT3. By completely inhibiting these mediators, verteporfin may be more efficacious in ameliorating LPA and/or IL6 trans-signaling–induced ocular hypertensive phenotypes in hTM cells.

Effects of topical TGF-β1, TGF-β2, ATX, and LPA on IOP elevation and regulation of the conventional aqueous humor outflow pathway

PURPOSE

The effects of aqueous mediators possibly increasing the outflow resistance, transforming growth factor-β1 (TGF-β1), TGF-β2, autotaxin (ATX), and lysophosphatidic acid (LPA) on human trabecular meshwork (hTM) cells and monkey Schlemm's canal endothelial (SCE) cells were characterized and compared, and the effects of intracameral application of these mediators on intraocular (IOP) elevation were also examined.

METHODS

Cells were treated with TGF-β1, TGF-β2, ATX, LPA, or vehicle, and mRNA and protein expression levels of α-SMA, COL1A1, fibronectin, β-catenin, and ZO-1 were examined with real-time quantitative PCR (RT-qPCR) or immunofluorescence analyses or both. The permeability of cell monolayers was measured by determining the transendothelial electrical resistance (TEER) or with the fluorescein isothiocyanate (FITC)-dextran permeability assay. IOP was evaluated in rabbit eyes after intracameral administration of the mediators.

RESULTS

All mediators induced upregulation of α-SMA, COL1A1, and fibronectin in hTM cells. The effect of TGF-β2 on mRNA expression of fibrotic markers was statistically significantly greater than that of TGF-β1. The effects of ATX and LPA indicated the time-dependent difference in the upregulation of α-SMA, COL1A1, and fibronectin. The TEER and FITC-dextran permeability of the SCE cells was evaluated after treatment with TGF-β1 and TGF-β2, but no statistically significant change was observed within 24 h. ATX and LPA also reduced permeability statistically significantly after 3 h and 0.5 h, respectively, and the effect of LPA was more rapid compared to that of ATX. Statistically significant IOP elevation was observed in rabbit eyes as early as 0.5-2.0 h after ATX and LPA treatment and at 24 h after treatment with TGF-β2.

CONCLUSIONS

TGF-β2 and ATX and LPA regulate aqueous outflow by modulation of hTM cells and SCE cells, and differences in timing between the effects of each mediator were observed. ATX and LPA showed more rapid effects on IOP elevation than TGF-β2. It was suggested that TGF-β2 and ATX/LPA are involved in increases of IOP, but the timing and sustainability differ between mediators, and they may play specific roles in different glaucoma subtypes.

Aqueous autotaxin and TGF-βs are promising diagnostic biomarkers for distinguishing open-angle glaucoma subtypes

The purpose of this study is to examine if aqueous autotaxin (ATX) and TGF-β levels could be used for differentiating glaucoma subtypes. This prospective observational study was performed using aqueous humor samples obtained from 281 consecutive patients. Open angle glaucoma patients were classified into three groups: primary open-angle glaucoma (POAG), secondary open-angle glaucoma (SOAG), and exfoliation glaucoma (XFG). Aqueous levels of ATX and TGF-βs were quantified. The AUC as well as sensitivity and specificity for the classification into normal and glaucoma subtypes using four indicators-ATX, TGF-β1, TGF-β2, and TGF-β3, upon the application of three machine learning methods. ATX, TGF-β1, and TGF-β3 were positively correlated with IOP, and ATX was significantly and negatively correlated with the mean deviation. From least absolute shrinkage and selection operator regression analysis, the AUC values to distinguish each subgroup [normal, POAG, SOAG, and XFG] ranged between 0.675 (POAG vs. normal) and 0.966 (XFG vs. normal), when four variables were used. High AUC values were obtained with ATX for discriminating XFG from normal eyes and with TGF-β3 for discriminating XFG from normal eyes, POAG, or SOAG. Aqueous TGF-β and ATX exhibited high diagnostic performance in detecting glaucoma subtypes, and could be promising biomarkers for glaucoma.

Effects of mammalian target of rapamycin inhibitors on fibrosis after trabeculectomy

Glaucoma, the second leading cause of blindness worldwide, is characterized by aberrant elevations of intraocular pressure (IOP), which can damage the optic nerve. IOP reduction is the only effective therapy for prevention of visual impairment and blindness in both hypertensive and normotensive individuals, and in some cases, trabeculectomy is a major surgical procedure that can lower IOP in patients with glaucoma. No matter how surgical technique and postoperative care advances, excessive scarring and tissue fibrosis could result from increased human conjunctival fibroblast (HCF) proliferation and extracellular matrix (ECM) deposition of the subconjunctival tissue and scleral flaps would persist after trabeculectomy. And these issues are major impediments to IOP reduction and filtering of bleb formations, so the modulation of the factors which can induce fibrosis could used as a novel strategy to control scarring after trabeculectomy. In this study, we examined the effects of mammalian target of rapamycin (mTOR) inhibitors (rapamycin or Torin1) on the fibrotic response induced by transforming growth factor-beta 1 (TGF-β1) in cultured human conjunctival fibroblast (HCF) cells. The study also examined the effects of mTOR inhibitor on fibrosis after trabeculectomy in rabbit eyes. In in vitro studies, we stimulated HCFs with TGF-β1, and confirmed that the expression levels of fibronectin, collagen type I alpha 1 chain (COL1A1), and α-smooth muscle actin (SMA) were significantly upregulated in HCFs with TGF-β1, by means of quantitative real-time polymerase chain reaction and immunocytochemistry. And those TGF-β1-induced changes were significantly attenuated with mTOR inhibitors, rapamycin or Torin1. Additionally the migration rate of HCFs was examined under conditions of TGF-β1 induction, TGF-β1-induced changes were significantly attenuated with mTOR inhibitors. A rabbit model of trabeculectomy was examined in vivo, and the effects of topical mTOR inhibitor were also examined, and found that topical treatment with mTOR inhibitor significantly suppressed collagen deposition in rabbit eyes after trabeculectomy. These results have demonstrated that mTOR inhibitors may provide a novel treatment modality for reducing the fibrotic response in HCFs and improving bleb scarring after filtration surgery.