Inflammation in Glaucoma: From the back to the front of the eye, and beyond

Real-Life Study on the Efficacy and Tolerance of a Preservative-Free Surfactant-Free Latanoprost Eye Drop in Patients with Glaucoma

INTRODUCTION

The purpose of this study is to assess the real-life efficacy and tolerance of a new preservative-free, surfactant-free latanoprost (PFSF-LAT) formulation.

METHODS

Retrospective, multicentre, non-comparative, observational study in patients with ocular hypertension or open angle glaucoma, naïve or non-naïve to previous intraocular pressure (IOP)-lowering treatment, and treated for at least 3 months with the study eye drop. IOP for worse eye, ocular signs and symptoms, and concomitant use of artificial tears were collected at study drug initiation and at last visit under treatment. Reasons for discontinuing the study eye drop (if relevant) and investigators' satisfaction were also assessed.

RESULTS

In the per protocol population (103 eyes; 63 naïve, 39 switched, 1 not classified because of missing data), IOP decreased significantly (p < 0.001) from 21.6 ± 5.0 mmHg at baseline to 16.1 ± 3.5 mmHg at the end of the study (mean reduction of - 5.5 ± 4.6 mmHg; - 25.5%). IOP in naïve patients was significantly improved, with a mean reduction of 7.1 mmHg (- 30.7%), which was within expected latanoprost IOP-lowering effect. Interestingly, in previously treated patients, switching to PFSF-LAT also allowed for a further 2.9 mmHg decrease in IOP (p < 0.001). The incidence of ocular side effects at study initiation was significantly (p < 0.001) reduced from 31.1% to 11.3% in the overall population, and from 65.0% to 7.5% in switched patients. This included conjunctival hyperaemia and superficial punctate keratitis (from 42.5% to 2.5% and from 37.5% to 2.5% in switched patients, respectively). According to investigators, tolerance and efficacy of the study eye drop were satisfactory or very satisfactory in 98.1% and 83.2% of patients, respectively.

CONCLUSION

PFSF-LAT is an efficient treatment for patients with glaucoma with an improved tolerance profile. It can be considered as initial therapy in naïve patients or in patients with poor ocular tolerance to previous IOP-lowering eye drops.

Genetic Risk, Inflammation, and Therapeutics: An Editorial Overview of Recent Advances in Aging Brains and Neurodegeneration

Neurodegenerative disorders, including Dementia, Parkinson's disease, various Vision disorders, Multiple sclerosis, and transsynaptic degenerative changes represent a significant challenge in aging populations. This editorial synthesizes and discusses recent advancements in understanding the genetic and environmental factors contributing to these diseases. Central to these advancements is the role of neuroinflammation and oxidative stress, which exacerbate neuronal damage and accelerate disease progression. Emerging research underscores the significance of mitochondrial dysfunction and protein aggregation in neurodegenerative pathology, highlighting shared mechanisms across various disorders. Innovative therapeutic strategies, including gene therapy, CRISPR-Cas technology, and the use of naturally occurring antioxidant molecules, are being investigated to target and manage these conditions. Additionally, lifestyle interventions such as exercise and healthy diet have shown promise in enhancing brain plasticity and reducing neuroinflammation. Advances in neuroimaging and biomarker discovery are necessary to improve early diagnosis, while clinical and preclinical studies are essential for the translation of these novel treatments. This edition aims to bridge the gap between molecular mechanisms and therapeutic applications, offering insights into potential interventions to mitigate the impact of neurodegenerative diseases. By establishing a deeper understanding of these complex processes, we aim to move closer to effective prevention and treatment strategies, ultimately improving the quality of life for those affected by neurodegenerative disorders.

Expert Consensus Recommendations for the Management of Ocular Surface Inflammation in Patients With Glaucoma

PRCIS

We have developed through a consensus process 24 clinical recommendations for the comprehensive management of ocular surface inflammation in glaucoma patients, including diagnostic criteria, prevention measures, and treatment strategies according to ocular surface disease severity.

PURPOSE

To obtain expert consensus on the diagnosis, prevention, and management of ocular surface inflammation (OSI) in patients with glaucoma.

METHODS

An international steering committee of glaucoma and/or ocular surface disease (OSD) experts and a wider faculty of members from the Educational Club of Ocular Surface and Glaucoma (ECOS-G) collaborated to develop clinical recommendations on best practice in the management of OSI in glaucoma patients using a nonanonymous interactive quasi-Delphi process. Clinical recommendations were formulated by the steering committee based on an analysis of the recent literature to determine unmet needs, together with a web-based interactive survey of faculty members' opinion in seven identified areas of OSI management in glaucoma. Topics included (1) diagnosis of OSD, (2) diagnosis of OSI, (3) causes of OSI, (4) impact of OSD/OSI, (5) prevention of OSI, (6) treatment of OSI, and (7) inflammation and the deep structures of the eye. Faculty members were invited to vote on the clinical recommendations, and the steering committee then determined whether consensus had been achieved.

RESULTS

Consensus was obtained on 24 clinical recommendations by 80%-100% of faculty members. There was consensus that OSI should be investigated in all glaucoma patients. The main prevention measure in glaucoma patients with pre-existing OSD was the elimination/minimisation of preserved medications, especially BAK-preserved eye drops. A subtractive treatment strategy rather than an additive strategy is recommended according to OSI/OSD severity to improve the ocular health and/or before glaucoma surgery.

CONCLUSION

These recommendations for the management of OSI in glaucoma should be useful to guide decision-making in clinical practice.

Mechanosensitive ion channels in glaucoma pathophysiology

Force sensing is a fundamental ability that allows cells and organisms to interact with their physical environment. The eye is constantly subjected to mechanical forces such as blinking and eye movements. Furthermore, elevated intraocular pressure (IOP) can cause mechanical strain at the optic nerve head, resulting in retinal ganglion cell death (RGC) in glaucoma. How mechanical stimuli are sensed and affect cellular physiology in the eye is unclear. Recent studies have shown that mechanosensitive ion channels are expressed in many ocular tissues relevant to glaucoma and may influence IOP regulation and RGC survival. Furthermore, variants in mechanosensitive ion channel genes may be associated with risk for primary open angle glaucoma. These findings suggest that mechanosensitive channels may be important mechanosensors mediating cellular responses to pressure signals in the eye. In this review, we focus on mechanosensitive ion channels from three major channel families-PIEZO, two-pore potassium and transient receptor potential channels. We review the key properties of these channels, their effects on cell function and physiology, and discuss their possible roles in glaucoma pathophysiology.

Caveolin-1 protects retinal ganglion cells in glaucoma by reducing TLR4 and activating the Akt/PTEN signaling pathway

Glaucoma is a degenerative disease characterized by retinal ganglion cell (RGC) death and visual impairment caused by elevated intraocular pressure (IOP). Elevated IOP can activate microglia, which participate in ganglion cell injury. Based on the study of caveolin-1 (Cav-1) in glaucoma, we aimed to explore the effect and mechanism of Cav-1 on RGC apoptosis in mice with acute ocular hypertension (AOH). AOH mice were established, and Cav-1 was intravitreally injected. Retinal microglia and RGCs were isolated from neonatal mice. TUNEL staining, hematoxylin-eosin staining, immunohistochemistry, flow cytometry, PCR and western blotting were used to observe the effect of Cav-1 on RGCs and mouse retinas. The thickness of the whole retina and the inner retinal sublayer decreased significantly, retinal cell apoptosis increased after AOH injury, and Cav-1 treatment reversed the effect of AOH injury. In addition, Cav-1 treatment promoted the conversion of proinflammatory M1 microglia to anti-inflammatory M2 microglia. Microglia and RGCs were isolated from neonatal mice. Cav-1 protects RGCs from OGD/R-induced injury by changing the polarization status of retinal microglia in vitro. Further studies revealed that Cav-1 activated the Akt/PTEN signaling pathway and inhibited TLR4. Our study provides evidence that Cav-1 may be a promising therapeutic target for glaucoma.

Histamine H3 receptor antagonist/nitric oxide donors as novel promising therapeutic hybrid-tools for glaucoma and retinal neuroprotection

Glaucoma is a degenerative optic neuropathy in which the degeneration of optic nerve and blindness occur. The main cause is a malfunction of ciliary processes (protrusions of the ciliary bodies) resulting in increased intraocular pressure (IOP). Ocular hypertension (OHT) causes ischemic events leading to retinal ganglion cell (RGC) depletion and blindness. Histaminergic and nitrergic systems are involved in the regulation of IOP. Therefore, we developed novel hybrid compounds that target histamine H3 receptor (H3R) with nitric oxide (NO) releasing features (ST-1989 and ST-2130). After H3R binding was proven in vitro, we investigated their effects in two OHT models in New Zealand White rabbits. Compound ST-1989 showed the highest NO elevation, together with antioxidative and anti-inflammatory features partly superior to the co-administered H3R antagonist (ciproxifan) and NO donor (molsidomine). This hybrid compound demonstrated IOP reduction in both OHT models induced by intravitreal injection of hypertonic saline and carbomer into the anterior chamber of the eye, respectively. Ocular perfusion and photoreceptor neuroprotection were evaluated in a model of ischemia/reperfusion (I/R) of the ophthalmic artery induced by repeated sub-tenon injections of endothelin-1 (ET-1), twice a week for six weeks. Compound ST-1989 counteracts retinal degeneration reducing ophthalmic artery resistance index and increasing photoreceptor responses, thus rescuing RGCs. Our results indicate that compound ST-1989 is a promising molecule with long-lasting hypotensive effects and good effectiveness in reducing inflammation, oxidative stress, and RGCs apoptosis. In conclusion, these hybrid compounds could be a novel strategy to combat glaucomatous blindness and RGC depletion for ocular diseases involving retinal damage.

Multi-functional, conformal systems with ultrathin crystalline-silicon-based bioelectronics for characterization of intraocular pressure and ocular surface temperature

Technologies that established in vivo evaluations of soft-tissue biomechanics and temperature are essential to biological research and clinical diagnostics, particularly for a wide range of eye-related diseases such as glaucoma. Of importance are advanced bioelectronic devices for high-precise monitoring of intraocular pressure (IOP) and various ocular temperatures, as clinically proven uses for glaucoma diagnosis. Existing characterization methods are temporary, single point, and lack microscale resolution, failing to measure continuous IOP fluctuation across the long-term period. Here, this work presents a multi-functional smart contact lens, capable of rapidly capturing IOP fluctuation and ocular surface temperature (OST) for assistance for clinical use. The microscale device design is programmable and determined by finite element analysis simulation, with detailed experiments of ex vivo porcine eyeballs. Such compact bioelectronics can provide high-precise measurement with sensitivity of 0.03% mmHg-1 and 1.2 Ω °C-1 in the range of Δ2∼50 mmHg and 30-50 °C, respectively. In vivo tests of bio-integration with a living rabbit can evaluate real-time IOP fluctuation and OST, as of biocompatibility assessments verified through cellular and animal experiments. The resultant bioelectronic devices for continuous precise characterization of living eyeballs can offer broad utility for hospital diagnosis of a wide range of eye-related disorders.

Evaluation of Rho kinase inhibitor effects on neuroprotection and neuroinflammation in an ex-vivo retinal explant model

BACKGROUND

Glaucoma is a leading cause of blindness, affecting retinal ganglion cells (RGCs) and their axons. By 2040, it is likely to affect 110 million people. Neuroinflammation, specifically through the release of proinflammatory cytokines by M1 microglial cells, plays a crucial role in glaucoma progression. Indeed, in post-mortem human studies, pre-clinical models, and ex-vivo models, RGC degeneration has been consistently shown to be linked to inflammation in response to cell death and tissue damage. Recently, Rho kinase inhibitors (ROCKis) have emerged as potential therapies for neuroinflammatory and neurodegenerative diseases. This study aimed to investigate the potential effects of three ROCKis (Y-27632, Y-33075, and H-1152) on retinal ganglion cell (RGC) loss and retinal neuroinflammation using an ex-vivo retinal explant model.

METHODS

Rat retinal explants underwent optic nerve axotomy and were treated with Y-27632, Y-33075, or H-1152. The neuroprotective effects on RGCs were evaluated using immunofluorescence and Brn3a-specific markers. Reactive glia and microglial activation were studied by GFAP, CD68, and Iba1 staining. Flow cytometry was used to quantify day ex-vivo 4 (DEV 4) microglial proliferation and M1 activation by measuring the number of CD11b+, CD68+, and CD11b+/CD68+ cells after treatment with control solvent or Y-33075. The modulation of gene expression was measured by RNA-seq analysis on control and Y-33075-treated explants and glial and pro-inflammatory cytokine gene expression was validated by RT-qPCR.

RESULTS

Y-27632 and H-1152 did not significantly protect RGCs. By contrast, at DEV 4, 50 µM Y-33075 significantly increased RGC survival. Immunohistology showed a reduced number of Iba1+/CD68+ cells and limited astrogliosis with Y-33075 treatment. Flow cytometry confirmed lower CD11b+, CD68+, and CD11b+/CD68+ cell numbers in the Y-33075 group. RNA-seq showed Y-33075 inhibited the expression of M1 microglial markers (Tnfα, Il-1β, Nos2) and glial markers (Gfap, Itgam, Cd68) and to reduce apoptosis, ferroptosis, inflammasome formation, complement activation, TLR pathway activation, and P2rx7 and Gpr84 gene expression. Conversely, Y-33075 upregulated RGC-specific markers, neurofilament formation, and neurotransmitter regulator expression, consistent with its neuroprotective effects.

CONCLUSION

Y-33075 demonstrates marked neuroprotective and anti-inflammatory effects, surpassing the other tested ROCKis (Y-27632 and H-1152) in preventing RGC death and reducing microglial inflammatory responses. These findings highlight its potential as a therapeutic option for glaucoma.

Oxygen, the Paradox of Life and the Eye

Oxidative stress, caused by the formation of free radicals, such as reactive oxygen species (ROS), leads to cell and tissue degradation, contributing to various diseases and aging. While oxygen is essential for aerobic organisms, it inevitably causes oxidative stress. Antioxidants protect against damage from free radicals, and oxidative stress arises when an imbalance occurs between free radical production and antioxidant defenses. However, when investigating whether an excess of antioxidants, almost eliminating oxidative stress, could benefit aging and disease susceptibility, it was observed that a basic level of oxidative stress appears necessary to maintain the correct homeostasis of tissues and organs and life in general. Therefore, this review aimed to compile the most significant and recent papers characterizing and describing the dual role of oxygen as a molecule essential for life and as a precursor of oxidative stress, which can be detrimental to life. We conducted targeted searches in PubMed and Google browsers to gather all relevant papers. We then focused on the eye, an organ particularly vulnerable due to its high metabolic activity combined with direct exposure to light and environmental pollutants, which produces a substantial number of free radicals (mainly ROS). We present a curated selection of relevant literature describing the main ocular pathologies of the posterior and anterior segments of the eye, highlighting oxidative stress as a significant contributing factor. Additionally, we report how endogenous and exogenous antioxidants can mitigate the development and progression of these diseases. Finally, we consider a frequently overlooked aspect: the balance between oxidants and antioxidants in maintaining the homeostatic equilibrium of tissues and organs. It is widely recognized that when oxidants overwhelm antioxidants, oxidative stress occurs, leading to negative consequences for the organism's homeostasis. However, we emphasize that a similarly dangerous situation can arise when the presence of antioxidants overwhelms the production of free radicals, drastically reducing their amount and adversely affecting aging and longevity. Unfortunately, no specific studies have addressed this particular situation in the eye.

Self-Assembly Hypoxic and ROS Dual Response Nano Prodrug as a New Therapeutic Approach for Glaucoma Treatments

Glaucoma is an irreversible blinding eye disease characterized by retinal ganglion cell (RGC) death.Previous studies have demonstrated that protecting mitochondria and activating the CaMKII/CREB signaling pathway can effectively protect RGC and axon. However, currently treatments are often unsatisfactory, and the pathogenesis of glaucoma requires further elucidation. In this study, a ROS-responsive dual drug conjugate (OLN monomer) is first designed that simultaneously bonds nicotinamide and oleic acid. The conjugate self-assembled into nanoparticles (uhOLN-NPs) through the aggregation of multiple micelles and possesses ROS scavenging capability. Then, a polymer with a hypoxic response function is designed, which encapsulates uhOLN-NPs to form nanoparticles with hypoxic and ROS responses (HOLN-NPs). Under hypoxia in RGCs, the azo bond of HOLN-NPs breaks and releases uhOLN-NPs. Meanwhile, under high ROS conditions, the thioketone bond broke, leading to the dissociation of nano-prodrug. The released nicotinamide and oleic acid co-scavenge ROS and activate the CaMKII/CREB pathway, protecting mitochondria in RGCs. HOLN-NPs exhibit a significantly superior protective effect on R28 cells in glutamate models of glaucoma. The accumulation of HOLN-NPs in retinal RGCs lead to significant inhibition of RGC apoptosis and axonal damage in vivo. Notably, HOLN-NPs provide a new therapeutic approach for patients with neurodegenerative disease.

Glaucoma: Current and New Therapeutic Approaches

Glaucoma is identified by the loss of retinal ganglion cells (RGCs). The primary approach to managing glaucoma is to control intraocular pressure (IOP). Lately, there has been an increasing focus on neuroprotective therapies for glaucoma because of the limited effectiveness of standard methods in reducing IOP and preventing ongoing vision deterioration in certain glaucoma patients. Various drug-based techniques with neuroprotective properties have demonstrated the ability to decrease the mortality of retinal ganglion cells. This study will analyze the currently recommended drug-based techniques for neuroprotection in the prospective treatment of glaucoma.

Delayed Surgical Reversal of Optic Nerve Compression Leads to Exponential Degeneration of Optic Nerve Fibers and Selective Sparing of the Small Fibers

Purpose

To evaluate the effectiveness of surgical reversal of experimental optic nerve compression in treating persistent compressive optic neuropathy and to explore the relationship between surgical outcomes and the timing of the procedure.

Methods

Surgical reversal procedures (decompression surgery) were conducted at five time intervals: 1, 3, and 7 days and 2 and 3 weeks following optic nerve compression in a rabbit model. The groups were labeled as DC-1d, DC-3d, DC-7d, DC-2w, and DC-3w, respectively. The study investigated changes in ganglion cell complex (GCC) thickness using spectral-domain optical coherence tomography and the percentage of surviving retinal ganglion cells (RGCs) through immunofluorescence staining and optic nerve axons stained with p-phenylenediamine at 4 weeks after decompression. Additionally, the area distribution of surviving axons was analyzed.

Results

The decline in GCC thickness was halted following decompression. The remaining thickness of the GCC in group DC-1d was found to be statistically significantly higher at 2, 3, and 4 weeks postonset compared to the no-decompression group. Similarly, GCC thickness in group DC-3d was significantly higher at 3 and 4 weeks postonset. The percentage of surviving RGCs and axons at 4 weeks postonset exhibited an exponential correlation with the onset time of decompression, with R2 values of 0.72 and 0.78, respectively. The surviving axon area declined following delayed decompression.

Conclusions

Persistent substantial compression on the optic nerve leads to exponential degeneration of the optic nerve, initially affecting larger optic nerve fibers. Early intervention aimed at relieving the compression on the optic nerve may offer potential benefits in mitigating the degenerative effects and conserving visual function.

Microglial cGAS-STING signaling underlies glaucoma pathogenesis

Characterized by progressive degeneration of retinal ganglion cells (RGCs) and vision loss, glaucoma is the primary cause of irreversible blindness, incurable and affecting over 78 million patients. However, pathogenic mechanisms leading to glaucoma-induced RGC loss are incompletely understood. Unexpectedly, we found that cGAS-STING (2'3'-cyclic GMP-AMP-stimulator of interferon genes) signaling, which surveils displaced double-stranded DNA (dsDNA) in the cytosol and initiates innate immune responses, was robustly activated during glaucoma in retinal microglia in distinct murine models. Global or microglial deletion of STING markedly relieved glaucoma symptoms and protected RGC degeneration and vision loss, while mice bearing genetic cGAS-STING supersensitivity aggravated retinal neuroinflammation and RGC loss. Mechanistically, dsDNA from tissue injury activated microglial cGAS-STING signaling, causing deleterious macroglia reactivity in retinas by cytokine-mediated microglia-macroglia interactions, progressively driving apoptotic death of RGCs. Remarkably, preclinical investigations of targeting cGAS-STING signaling by intraocular injection of TBK1i or anti-IFNAR1 antibody prevented glaucoma-induced losses of RGCs and vision. Therefore, we unravel an essential role of cGAS-STING signaling underlying glaucoma pathogenesis and suggest promising therapeutic strategies for treating this devastating disease.

Lifestyle Changes in Aging and their Potential Impact on POAG

Primary open angle glaucoma is a primary mitochondrial disease with oxidative stress triggering neuroinflammation, eventually resulting in neurodegeneration. This affects many other areas of the brain in addition to the visual system. Aging also leads to inflammaging - a low-grade chronic inflammatory reaction in mitochondrial dysfunction, so these inflammatory processes overlap in the aging process and intensify pathophysiological processes associated with glaucoma. Actively counteracting these inflammatory events involves optimising treatment for any manifest systemic diseases while maintaining chronobiology and improving the microbiome. Physical and mental activity also provides support. This requires a holistic approach towards optimising neurodegeneration treatment in primary open angle glaucoma in addition to reducing intraocular pressure according personalised patient targets.

Proteomic and Cytokine Profiling in Plasma from Patients with Normal-Tension Glaucoma and Ocular Hypertension

Primary open-angle glaucoma (POAG) is subdivided depending on eye pressure. Patients with normal-tension glaucoma (NTG) have never had high intraocular pressure (IOP) measured while patients with ocular hypertension (OHT) have high eye pressure but no signs of glaucoma. Although IOP is considered to be a risk factor for all glaucoma patients, it is reasonable to assume that other risk factors such as inflammation play a role. We aimed to characterize the proteome and cytokine profile during hypoxia in plasma from patients with NTG (n = 10), OHT (n = 10), and controls (n = 10). Participants were exposed to hypoxia for two hours, followed by 30 min of normoxia. Samples were taken before ("baseline"), during ("hypoxia"), and after hypoxia ("recovery"). Proteomics based on liquid chromatography coupled with mass spectrometry (LC-MS) was performed. Cytokines were measured by Luminex assays. Bioinformatic analyses indicated the involvement of complement and coagulation cascades in NTG and OHT. Regulation of high-density lipoprotein 3 (HDL3) apolipoproteins suggested that changes in cholesterol metabolism are related to OHT. Hypoxia decreased the level of tumor necrosis factor-α (TNF-α) in OHT patients compared to controls. Circulating levels of interleukin-1β (IL-1β) and C-reactive protein (CRP) were decreased in NTG patients compared to controls during hypoxia. After recovery, plasma interleukin-6 (IL-6) was upregulated in patients with NTG and OHT. Current results indicate an enhanced systemic immune response in patients with NTG and OHT, which correlates with pathogenic events in glaucoma. Apolipoproteins may have anti-inflammatory effects, enabling OHT patients to withstand inflammation and development of glaucoma despite high IOP.

Efficacy and Safety of a Preservative-Free Latanoprost Cationic Emulsion in Patients with Open-Angle Glaucoma and Concurrent Ocular Surface Disease: A Randomized Phase 2 Study

Purpose: To compare intraocular pressure (IOP), ocular surface disease (OSD) parameters, and safety in patients with open-angle glaucoma (OAG)/ocular hypertension (OH) and concurrent OSD treated with preservative-free latanoprost 0.005% cationic emulsion (PF-latanoprost-E) or travoprost-Z 0.004% ophthalmical solution containing a soft preservative system. Methods: Patients with OAG/OH and OSD were randomized to treatment with PF-latanoprost-E or travoprost-Z nightly for 3 months. Outcomes included mean diurnal IOP reduction; OSD endpoints, including symptom improvement, tear break-up time (TBUT), and corneal fluorescein staining (CFS) score; and safety after 1 and 3 months. Results: A total of 105 patients were randomized, 51 to PF-latanoprost-E and 54 to travoprost-Z. IOP reductions (LS mean differences) at 3 months were numerically greater in the PF-latanoprost-E than in the travoprost-Z group at 8AM (7.2 versus 6.0 mmHg), 10AM (6.7 versus 5.9 mmHg), and 4PM (6.0 versus 5.4 mmHg). LS mean changes in IOP from baseline in both groups at 1 and 3 months, however, were comparable. Mean ± SD CFS scores on the Ora scale at month 3 showed significantly greater reductions in the PF-latanoprost-E than in the travoprost-Z group (-1.07 ± 1.863 versus -0.16 ± 2.553 P = 0.0461). The mean TBUT at month 3 showed similar improvements in both groups (1.1 versus 1.0 s, P > 0.05). OSD symptoms improved but did not differ significantly in the two groups. Overall safety was comparable in both groups. Conclusion: PF-latanoprost-E effectively and safely lowered IOP and improved OSD parameters in patients with OAG/OH. These findings provide evidence for the beneficial effects of this new formulation of latanoprost in glaucoma patients with OSD.

α-1 antitrypsin is promising for the identification of glaucoma severity and is associated with glaucomatous neural damage

Aim: To investigate the association between plasma AAT level and glaucoma.Methods: 163 glaucoma patients and 111 healthy controls were recruited. The plasma AAT levels were measured by ELISA.Results: Plasma AAT level was significantly higher in glaucoma patients than those in healthy controls (p < 0.001). Patients with higher plasma AAT level exhibited severer disease stage (early vs. severe: p < 0.05; H-P-A; early vs. severe: p < 0.05; early vs. end-stage: p < 0.01; AGIS). ROC curves yielded that AAT can distinguish patients with early glaucoma from those with advanced glaucoma (early vs. severe: AUC: 0.616; H-P-A; early vs. severe: AUC: 0.763; early vs. end-stage: AUC: 0.660; AGIS).Conclusion: Plasma AAT is a useful biomarker for the identification of glaucoma severity.

Preservatives and ocular surface disease: A review

Ocular surface disease (OSD) is a complex condition that can cause a range of symptoms (e.g, dryness, irritation, and pain) and can significantly impact the quality of life of affected individuals. Iatrogenic OSD, a common finding in patients with glaucoma who receive chronic therapy with topical ocular antihypertensive drugs containing preservatives such as benzalkonium chloride (BAK), has been linked to damage to the ocular surface barrier, corneal epithelial cells, nerves, conjunctival goblet cells, and trabecular meshwork. Chronic BAK exposure activates inflammatory pathways and worsens symptoms, compromising the success of subsequent filtration surgery in an exposure-dependent manner. In eyes being treated for glaucoma, symptomatic treatment of OSD may provide some relief, but addressing the root cause of the OSD often necessitates reducing or, ideally, eliminating BAK toxicity. Strategies to decrease BAK exposure in patients with glaucoma encompass the use of preservative-free formulations or drugs with alternative and less toxic preservatives such as SofZia®, Polyquad, potassium sorbate, or Purite®. Though the benefits of these alternative preservatives are largely unproven, they might be considered when financial constraints prevent the use of preservative-free versions. For patients receiving multiple topical preserved drugs, the best practice is to switch to nonpreserved equivalents wherever feasible, regardless of OSD severity. Furthermore, nonpharmacological approaches, including laser or incisional procedures, should be considered. This review explores the effects of BAK on the ocular surface and reviews strategies for minimizing or eliminating BAK exposure in patients with glaucoma in order to significantly improve their quality of life and prevent complications associated with chronic exposure to BAK.

Identification of Optic Nerve-Related Biomarkers in Primary Open-Angle Glaucoma Based on Comprehensive Bioinformatics and Mendelian Randomization

Purpose

Glaucoma is the primary cause of permanent vision loss worldwide. However, the pathogenesis of primary open-angle glaucoma (POAG), the main type of glaucoma, has not yet been completely understood.

Methods

In our study, the POAG cohorts were obtained from the Gene Expression Omnibus (GEO) database (GSE45570). Biomarkers with diagnostic utility for POAG were identified through combining differentially expressed analysis, enrichment analysis, machine learning algorithms, and receiver operating characteristic (ROC) analysis. The regulatory networks (including a competing endogenous RNA (ceRNA) regulatory network and a small molecule compounds-mRNA network) were created. In addition, the Mendelian randomization (MR) analysis was used to identify exposures causally associated with POAG. Finally, the expression of the biomarkers was validated via real-time quantitative polymerase chain reaction (RT-qPCR).

Results

The Gene Ontology (GO) items that the differentially expressed genes (DEGs) between POAG and control groups enriched were relevant to light stimulation and DNA methylation. A total of three light stimulation-related biomarkers (RAB8A, PRG3, and SMAD3) were identified, which had diagnostic value for POAG patients. Besides, the ceRNA regulatory network contained 88 nodes and 93 edges, and a small molecule compounds-mRNA network included 66 nodes and 76 edges. The MR results indicated a causal association between DNA methylation GrimAge acceleration and POAG. Additionally, the results of RT-qPCR revealed that the expression trend of RAB8A was consistent with that of GSE45570.

Conclusions

Taken together, this study provides three light stimulation-related biomarkers (RAB8A, PRG3, and SMAD3) for the diagnosis of POAG, providing scientifically valuable insights for further studies of POAG.

Translational Relevance

Discovering biomarkers that possess diagnostic significance for POAG has the potential to offer new insights into the pathogenesis of POAG and present novel objectives for clinical intervention.

Heterozygous Pyrin (MEFV) E148Q allele carriers indicate a reduced glaucoma risk for Turkish population: a prospective clinical analysis

PURPOSE

The MEFV gene encodes pyrin, a protein linked to increased severity of symptoms in Familial Mediterranean Fever (FMF). We consider that inflammation due to MEFV variants would increase eye inflammation and damage aqueous humor regulation. The present study is the first analysis investigating a MEFV (E148Q) variant as a marker protecting from glaucoma.

METHODS

In this prospective clinical analyze, we performed detailed gene sequencing focusing on 22 specific regions of the pyrin (MEFV) gene. The study involved two distinct groups: individuals diagnosed with glaucoma (n = 200) and control subjects without glaucoma (n = 100). Both groups were carefully selected to exclude individuals with symptoms or a previous diagnosis of Familial Mediterranean Fever (FMF). The diagnosis of glaucoma for each participant was rigorously established through comprehensive direct ophthalmic examinations.

RESULTS

A significant odds ratio for protection against glaucoma was found in carriers of the subclinical E148Q allele (OR:2.22; 95%CI: 1.098-4.485). No significant differences were found for other variants. One mutant E148Q-allele could decrease the probability of glaucoma development by approximately 68,9%. We observed no differences in the genotype frequency between glaucoma and healthy for the other MEFV gene variants.

CONCLUSION

The pyrin variant of the MEFV gene resulting in a subclinical phenotype appears to reduce the incidence of glaucoma, and heterozygous pyrin (MEFV) E148Q allele carriers confer protection against glaucoma. It is important to consider the limitations arising from the relatively small number of studies conducted on this topic.

Integrated Bioinformatics-Based Identification and Validation of Neuroinflammation-Related Hub Genes in Primary Open-Angle Glaucoma

Glaucoma is a leading cause of permanent blindness, affecting 80 million people worldwide. Recent studies have emphasized the importance of neuroinflammation in the early stages of glaucoma, involving immune and glial cells. To investigate this further, we used the GSE27276 dataset from the GEO (Gene Expression Omnibus) database and neuroinflammation genes from the GeneCards database to identify differentially expressed neuroinflammation-related genes associated with primary open-angle glaucoma (POAG). Subsequently, these genes were submitted to Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes for pathway enrichment analyses. Hub genes were picked out through protein-protein interaction networks and further validated using the external datasets (GSE13534 and GSE9944) and real-time PCR analysis. The gene-miRNA regulatory network, receiver operating characteristic (ROC) curve, genome-wide association study (GWAS), and regional expression analysis were performed to further validate the involvement of hub genes in glaucoma. A total of 179 differentially expressed genes were identified, comprising 60 upregulated and 119 downregulated genes. Among them, 18 differentially expressed neuroinflammation-related genes were found to overlap between the differentially expressed genes and neuroinflammation-related genes, with six genes (SERPINA3, LCN2, MMP3, S100A9, IL1RN, and HP) identified as potential hub genes. These genes were related to the IL-17 signaling pathway and tyrosine metabolism. The gene-miRNA regulatory network showed that these hub genes were regulated by 118 miRNAs. Notably, GWAS data analysis successfully identified significant single nucleotide polymorphisms (SNPs) corresponding to these six hub genes. ROC curve analysis indicated that our genes showed significant accuracy in POAG. The expression of these genes was further confirmed in microglia, Müller cells, astrocytes, and retinal ganglion cells in the Spectacle database. Moreover, three hub genes, SERPINA3, IL1R1, and LCN2, were validated as potential diagnostic biomarkers for high-risk glaucoma patients, showing increased expression in the OGD/R-induced glaucoma model. This study suggests that the identified hub genes may influence the development of POAG by regulation of neuroinflammation, and it may offer novel insights into the management of POAG.

Corneal application of SOCS1/3 peptides for the treatment of eye diseases mediated by inflammation and oxidative stress

Several blinding diseases affecting the retina and optic nerve are exacerbated by or caused by dysregulated inflammation and oxidative stress. These diseases include uveitis, age related macular degeneration, diabetic retinopathy and glaucoma. Consequently, despite their divergent symptoms, treatments that reduce oxidative stress and suppress inflammation may be therapeutic. The production of inflammatory cytokines and their activities are regulated by a class of proteins termed Suppressors of Cytokine Signaling (SOCS). SOCS1 and SOCS3 are known to dampen signaling via pathways employing Janus kinases and signal transducer and activator of transcription proteins (JAK/STAT), Toll-like Receptors (TLR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), mitogen activated kinase (MAPK) and NLR family pyrin domain containing 3 (NLRP3). We have developed cell-penetrating peptides from the kinase inhibitory region of the SOCS1 and SOCS3 (denoted as R9-SOCS1-KIR and R9-SOCS3-KIR) and tested them in retinal pigment epithelium (RPE) cells and in macrophage cell lines. SOCS-KIR peptides exhibited anti-inflammatory, anti-oxidant and anti-angiogenic properties. In cell culture, both Th1 and Th17 cells were suppressed together with the inhibition of other inflammatory markers. We also observed a decrease in oxidants and a simultaneous rise in neuroprotective and anti-oxidant effectors. In addition, treatment prevented the loss of gap junction proteins and the ensuing drop in transepithelial electrical resistance in RPE cells. When tested in mouse models by eye drop instillation, they showed protection against autoimmune uveitis, as a prophylactic as well as a therapeutic. Mice with endotoxin-induced uveitis were protected by eye drop administration as well. R9-SOCS3-KIR was particularly effective against the pathways acting through STAT3, e.g. IL-6 and VEGF-A mediated responses that lead to macular degeneration. Eye drop administration of R9-SOCS3-KIR stimulated production of antioxidant effectors and reduced clinical symptoms in mouse model of oxidative stress that replicates the RPE injury occurring in AMD. Because these peptides suppress multiple pathogenic stimuli and because they can be delivered topically to the cornea, they are attractive candidates for therapeutics for uveitis, macular degeneration, diabetic retinopathy and glaucoma.

Lycium Barbarum Polysaccharide-Derived Nanoparticles Protect Visual Function by Inhibiting RGC Ferroptosis and Microglial Activation in Retinal Ischemia‒Reperfusion Mice

Retinal ischemia‒reperfusion (IR) is a major contributor to vision impairment and irreversible vision loss due to retinal ganglion cell (RGC) injury or loss. Contemporary therapeutic approaches predominantly focus on the amelioration of symptoms rather than addressing the fundamental etiological factors. Oxidative stress is a notable feature and an important mediator of IR damage. Lycium barbarum polysaccharide (LBP), the main active ingredient of Lycium barbarum, has various pharmacological effects, including antioxidation, immunoregulation, and neuroprotective effects. In this study, the ROS-consumable moiety phenylboronic acid pinacol ester (PBA) is introduced to LBP molecules, which can self-assemble into nanoparticles in aqueous solution. This nanoparticle (termed PLBP) can reduce the cellular ROS levels and enhance the antioxidant capability of RGCs by activating the NRF2 pathway, thus protecting RGCs from ferroptosis and preserving visual function in response to IR injury. PLBP also reduces neuroinflammation by inhibiting the ability of microglia to phagocytose, migrate, secrete inflammatory cytokines, and activate the NF-κB pathway. In conclusion, this approach can be used as an inspiration for the future development of neuroprotective drugs.

Genome-wide RNA sequencing of ocular fibroblasts from glaucomatous and normal eyes: Implications for glaucoma management

Primary open angle glaucoma is a leading cause of visual impairment and blindness which is commonly treated with drugs or laser but may require surgery. Tenon's ocular fibroblasts are involved in wound-healing after glaucoma filtration surgery and may compromise a favourable outcome of glaucoma surgery by contributing to fibrosis. To investigate changes in gene expression and key pathways contributing to the glaucomatous state we performed genome-wide RNA sequencing. Human Tenon's ocular fibroblasts were cultured from normal and glaucomatous human donors undergoing eye surgery (n = 12). mRNA was extracted and RNA-Seq performed on the Illumina platform. Differentially expressed genes were identified using a bioinformatics pipeline consisting of FastQC, STAR, FeatureCounts and edgeR. Changes in biological functions and pathways were determined using Enrichr and clustered using Cytoscape. A total of 5817 genes were differentially expressed between Tenon's ocular fibroblasts from normal versus glaucomatous eyes. Enrichment analysis showed 787 significantly different biological functions and pathways which were clustered into 176 clusters. Tenon's ocular fibroblasts from glaucomatous eyes showed signs of fibrosis with fibroblast to myofibroblast transdifferentiation and associated changes in mitochondrial fission, remodeling of the extracellular matrix, proliferation, unfolded protein response, inflammation and apoptosis which may relate to the pathogenesis of glaucoma or the detrimental effects of topical glaucoma therapies. Altered gene expression in glaucomatous Tenon's ocular fibroblasts may contribute to an unfavourable outcome of glaucoma filtration surgery. This work presents a genome-wide transcriptome of glaucomatous versus normal Tenon's ocular fibroblasts which may identify genes or pathways of therapeutic value to improve surgical outcomes.

Potential Immune-Inflammatory Proteome Biomarkers for Guiding the Treatment of Patients with Primary Acute Angle-Closure Glaucoma Caused by COVID-19

Primary acute angle-closure glaucoma (PAACG) is a sight-threatening condition that can lead to blindness. With the increasing incidence of COVID-19, a multitude of people are experiencing acute vision loss and severe swelling of the eyes and head. These patients were then diagnosed with acute angle closure, with or without a history of PACG. However, the mechanism by which viral infection causes PACG has not been clarified. This is the first study to explore the specific inflammatory proteomic landscape in SARS-CoV-2-induced PAACG. The expression of 92 inflammation-related proteins in 19 aqueous humor samples from PAACGs or cataract patients was detected using the Olink Target 96 Inflammation Panel based on a highly sensitive and specific proximity extension assay technology. The results showed that 76 proteins were significantly more abundant in the PAACG group than in the cataract group. Notably, the top eight differentially expressed proteins were IL-8, MCP-1, TNFRSF9, DNER, CCL4, Flt3L, CXCL10, and CD40. Generally, immune markers are related to inflammation, macrophage activation, and viral infection, revealing the crucial role of macrophages in the occurrence of PAACGs caused by SARS-CoV-2.

Lycium ruthenicum water extract preserves retinal ganglion cells in chronic ocular hypertension mouse models

Lycium ruthenicum Murray (LR), known as "black goji berry" or "black wolfberry", is widely utilized in chinese herbal medicine. LR fruit showed its antioxidant and/or anti-inflammation activity in treating cardiac injury, experimental colitis, nonalcoholic fatty liver disease, fatigue, and aging. Glaucoma is the leading cause of irreversible blindness. Besides elevated intraocular pressure (IOP), oxidative stress and neuroinflammation were recognized to contribute to the pathogenesis of glaucoma. This study investigated the treatment effects of LR water extract (LRE) on retinal ganglion cells (RGCs) threatened by sustained IOP elevation in a laser-induced chronic ocular hypertension (COH) mouse model and the DBA/2J mouse strain. The antioxidation and anti-inflammation effects of LRE were further tested in the H2O2-challenged immortalized microglial (IMG) cell line in vitro. LRE oral feeding (2 g/kg) preserved the function of RGCs and promoted their survival in both models mimicking glaucoma. LRE decreased 8-hydroxyguanosine (oxidative stress marker) expression in the retina. LRE reduced the number of Iba-1+ microglia in the retina of COH mice, but not in the DBA/2J mice. At the mRNA level, LRE reversed the COH induced HO-1 and SOD-2 overexpressions in the retina of COH mice. Further in vitro study demonstrated that LRE pretreatment to IMG cells could significantly reduce H2O2 induced oxidative stress through upregulation of GPX-4, Prdx-5, HO-1, and SOD-2. Our work demonstrated that daily oral intake of LRE can be used as a preventative/treatment agent to protect RGCs under high IOP stress probably through reducing oxidative stress and inhibiting microglial activation in the retina.

XEN45 Implant in Medically Controlled vs. Uncontrolled Eyes-Differential IOP Changes in Real-Life Conditions

Background: To assess intraocular pressure (IOP) changes and complications after XEN45 implants in medically controlled eyes (MCE) vs. medically uncontrolled eyes (MUE). Methods: A retrospective study, in a tertiary referral hospital, on mild-to-moderate primary open-angle glaucoma (POAG) cases under topical medication, including 32 eyes with IOP < 21 mmHg (MCE group) and 30 eyes with IOP ≥ 21 mmHg (MUE group). The success criteria using Kaplan-Meier analysis was IOP < 21 mmHg without medications (complete success) or fewer drugs than preoperatively (qualified success) at the last visit, without new surgery or unresolved hypotony. Results: No significant preoperative differences were found between the groups. The mean IOP was 15.6 ± 3.8 mmHg in MCE and 15.1 ± 4.1 mmHg in the MUE group (p > 0.05; Mann-Whitney test) at the end of the follow-up (mean of 26.1 ± 15.6 months and 28.3 ± 15.3 months, respectively) (p = 0.414, Mann-Whitney Test). The device caused a significant IOP reduction at 24 h in both groups. Thereafter, the MCE group significantly tended to increase IOP, recovering baseline values at 1 month and maintaining them until the end of the follow-up. In contrast, in the MUE group, the IOP values tended to be similar after the first reduction. No relevant complications and no significant differences between the groups in the survival analysis were found. Conclusions: XEN45 provided stable IOP control in both the MCE and MUE group without important complications in the medium term. The IOP increasing in the MCE group, after a prior decrease, led to restored baseline values 1 month after surgery. The homeostatic mechanism that causes the rise in the IOP to baseline values and its relationship with failure cases remains to be clarified.

TLR4 deficiency does not alter glaucomatous progression in a mouse model of chronic glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide. Toll-like receptor 4 (TLR4) is a pattern-recognition transmembrane receptor that induces neuroinflammatory processes in response to injury. Tlr4 is highly expressed in ocular tissues and is known to modulate inflammatory processes in both anterior and posterior segment tissues. TLR4 activation can lead to mitochondrial dysfunction and metabolic deficits in inflammatory disorders. Due to its effects on inflammation and metabolism, TLR4 is a candidate to participate in glaucoma pathogenesis. It has been suggested as a therapeutic target based on studies using acute models, such as experimentally raising IOP to ischemia-inducing levels. Nevertheless, its role in chronic glaucoma needs further evaluation. In the current study, we investigated the role of TLR4 in an inherited mouse model of chronic glaucoma, DBA/2J. To do this, we analyzed the effect of Tlr4 knockout (Tlr4 -/-) on glaucoma-associated phenotypes in DBA/2J mice. Our studies found no significant differences in intraocular pressure, iris disease, or glaucomatous progression in Tlr4 -/- compared to Tlr4 +/+ DBA/2J mice. These data do not identify a role for TLR4 in this chronic glaucoma, but further research is warranted to understand its role in other glaucoma models and different genetic contexts.

Neuroprotective effects of resveratrol on retinal ganglion cells in glaucoma in rodents: A narrative review

Glaucoma, an irreversible optic neuropathy, primarily affects retinal ganglion cells (RGC) and causes vision loss and blindness. The damage to RGCs in glaucoma occurs by various mechanisms, including elevated intraocular pressure, oxidative stress, inflammation, and other neurodegenerative processes. As the disease progresses, the loss of RGCs leads to vision loss. Therefore, protecting RGCs from damage and promoting their survival are important goals in managing glaucoma. In this regard, resveratrol (RES), a polyphenolic phytoalexin, exerts antioxidant effects and slows down the evolution and progression of glaucoma. The present review shows that RES plays a protective role in RGCs in cases of ischemic injury and hypoxia as well as in ErbB2 protein expression in the retina. Additionally, RES plays protective roles in RGCs by promoting cell growth, reducing apoptosis, and decreasing oxidative stress in H2O2-exposed RGCs. RES was also found to inhibit oxidative stress damage in RGCs and suppress the activation of mitogen-activated protein kinase signaling pathways. RES could alleviate retinal function impairment by suppressing the hypoxia-inducible factor-1 alpha/vascular endothelial growth factor and p38/p53 axes while stimulating the PI3K/Akt pathway. Therefore, RES might exert potential therapeutic effects for managing glaucoma by protecting RGCs from damage and promoting their survival.

The significance of precisely regulating heme oxygenase-1 expression: Another avenue for treating age-related ocular disease?

Aging entails the deterioration of the body's organs, including overall damages at both the genetic and cellular levels. The prevalence of age-related ocular disease such as macular degeneration, dry eye diseases, glaucoma and cataracts is increasing as the world's population ages, imposing a considerable economic burden on individuals and society. The development of age-related ocular disease is predominantly triggered by oxidative stress and chronic inflammatory reaction. Heme oxygenase-1 (HO-1) is a crucial antioxidant that mediates the degradative process of endogenous iron protoporphyrin heme. It catalyzes the rate-limiting step of the heme degradation reaction, and releases the metabolites such as carbon monoxide (CO), ferrous, and biliverdin (BV). The potent scavenging activity of these metabolites can help to defend against peroxides, peroxynitrite, hydroxyl, and superoxide radicals. Other than directly decomposing endogenous oxidizing substances (hemoglobin), HO-1 is also a critical regulator of inflammatory cells and tissue damage, exerting its anti-inflammation activity through regulating complex inflammatory networks. Therefore, promoting HO-1 expression may act as a promising therapeutic strategy for the age-related ocular disease. However, emerging evidences suggest that the overexpression of HO-1 significantly contributes to ferroptosis due to its dual nature. Surplus HO-1 leads to excessive Fe2+ and reactive oxygen species, thereby causing lipid peroxidation and ferroptosis. In this review, we elucidate the role of HO-1 in countering age-related disease, and summarize recent pharmacological trials that targeting HO-1 for disease management. Further refinements of the knowledge would position HO-1 as a novel therapeutic target for age-related ocular disease.

Correlation Between Anterior Chamber Angle Status and Limbal Stem Cell Deficiency in Primary Angle-Closure Glaucoma

PURPOSE

To investigate the correlation between the opening and closing states of anterior chamber angle (ACA) and the density of limbal epithelial basal cells (LEBCs) in subjects with primary angle-closure glaucoma (PACG).

DESIGN

Cross-sectional observational study.

METHODS

A total of 54 eyes of 29 patients diagnosed with PACG were included in the study. Fifty-four eyes from normal subjects were included as control. Automatic evaluation system for ultrasound biomicroscopy images of anterior chamber angle was used to assist ophthalmologists in identifying the opening or closing state of ACA, and the in vivo confocal microscopy (IVCM) was used to evaluate the density of LEBCs in different directions.

RESULTS

(1) The average density of LEBCs in the superior, inferior, nasal, and temporal limbus of the eyes in the PACG group was lower than that in the control group, and this pattern did not align with the density distribution observed in the control group. (2) In the early, moderate and advanced PACG, the density of LEBCs corresponding to the closed angle was lower than that in the control group (P < .05). Compared with the density of LEBCs corresponding to the closed angle and the open angle, the closed angle of PACG in the early, moderate and advanced stages was less than that in the open angle (P < .05 in the early and moderate stages; advanced stage P > .05). (3) The basal cell density was processed by dimensionless analysis. In the data calculated by averaging and minimizing, both closed angle dimensionless values were smaller than the open angle (P < .05). (4) Comparative analysis was conducted among the normal, open-angle, and closed-angle conditions in the superior, inferior, nasal, and temporal limbus. In the early stage of PACG, significant differences were observed in 4 limbal regions (P < .05), while in the moderate PACG stage, this difference was noted in 3 limbal regions (P < .05). In advanced PACG, 2 limbal regions exhibited significant differences (P < .05). These findings suggest that during the early PACG stage, angle closure is the predominant influencing factor on LEBCs density, while in the advanced stage, the decrease in density is attributed to a combination of angle closure and the natural progression of the disease.

CONCLUSIONS

There is a significant correlation between anterior chamber angle status and LEBCs. Advanced PACG and angle closure should be highly suspected of the occurrence of limbal stem cell deficiency (LSCD).

Amyloid-beta and tau protein beyond Alzheimer's disease

ABSTRACT

The aggregation of amyloid-beta peptide and tau protein dysregulation are implicated to play key roles in Alzheimer's disease pathogenesis and are considered the main pathological hallmarks of this devastating disease. Physiologically, these two proteins are produced and expressed within the normal human body. However, under pathological conditions, abnormal expression, post-translational modifications, conformational changes, and truncation can make these proteins prone to aggregation, triggering specific disease-related cascades. Recent studies have indicated associations between aberrant behavior of amyloid-beta and tau proteins and various neurological diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, as well as retinal neurodegenerative diseases like Glaucoma and age-related macular degeneration. Additionally, these proteins have been linked to cardiovascular disease, cancer, traumatic brain injury, and diabetes, which are all leading causes of morbidity and mortality. In this comprehensive review, we provide an overview of the connections between amyloid-beta and tau proteins and a spectrum of disorders.

Formulation, optimization and evaluation of ocular gel containing nebivolol Hcl-loaded ultradeformable spanlastics nanovesicles: In vitro and in vivo studies

The study aims to improve the ocular delivery of Nebivolol HCL (NBV) belonging to the Biopharmaceutics classification system (BCSII) by using spanlastic nanovesicles (SNVs) for ophthalmic delivery and incorporating them into hydroxypropyl methylcellulose gel with ketorolac tromethamine (KET) as an anti-inflammatory to improve glaucoma complications like Conjunctivitis. SNVs were prepared by ethanol injection technique using span (60) as a surfactant and labrasol as an edge activator (EA). The impact of formulation factors on SNVs properties was investigated using a Box-Behnken design. In vitro evaluations showed that the formulations (F1, F4, and F14), containing Span 60 and labrasol as EA (25%, 50%, and 25%), exhibited high EE% with low PS and high ZP and DI. Additionally, 61.72 ± 0.77%, 58.97 ± 1.44%, and 56.20 ± 2.32% of the NBV amount were released from F1, F4, and F14 after 5 h, compared to 93.94 ± 1.21% released from drug suspension. The selected formula (G1), containing F1 in combination with KET and 2% w/w HPMC, exhibited 76.36 ± 0.90% drug release after 12 h. Ex vivo Confocal laser scanning revealed a high penetration of NBV-SNVs gel that ascertained the results of the in-vitro study. In vivo studies showed a significant decrease in glaucoma compared to drug suspension, and histopathological studies showed improvement in glaucomatous eye retinal atrophy. G1 is considered a promising approach to improving ocular permeability, absorption, and anti-inflammatory activity, providing a safer alternative to current regimens.

Depression and Eye Disease-A Narrative Review of Common Underlying Pathophysiological Mechanisms and their Potential Applications

Background: Depression has been shown to be associated with eye diseases, including dry eye disease (DED), cataracts, glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR). This narrative review explores potential pathophysiological connections between depression and eye disease, as well as its potential correlations with ocular parameters. Methods: A literature search was conducted in August 2022 in PUBMED, EMBASE, and PsycINFO. Published articles related to the subject were consolidated and classified according to respective eye diseases and pathophysiological mechanisms. Results: The literature reviewed suggests that common pathophysiological states like inflammation and neurodegeneration may contribute to both depression and certain eye diseases, while somatic symptoms and altered physiology, such as disruptions in circadian rhythm due to eye diseases, can also influence patients' mood states. Grounded in the shared embryological, anatomical, and physiological features between the eye and the brain, depression is also correlated to changes observed in non-invasive ophthalmological imaging modalities, such as changes in the retinal nerve fibre layer and retinal microvasculature. Conclusions: There is substantial evidence of a close association between depression and eye diseases. Understanding the underlying concepts can inform further research on treatment options and monitoring of depression based on ocular parameters.

The risk of open angle glaucoma in young adults with allergic diseases: a Nationwide cohort study

This study investigated the potential associations between allergic diseases (asthma, allergic rhinitis, and atopic dermatitis) and the development of primary open-angle glaucoma. We utilized authorized data from the Korean National Health Information Database (KNHID), which provides comprehensive medical claims data and information from the National Health Screening Program. We compared the baseline characteristics of subjects with and without allergic diseases and calculated the incidence and risk of glaucoma development. Cox proportional hazard regression analysis was used to determine the risk of glaucoma development in subjects with allergic diseases. A total of 171,129 subjects aged 20-39 with or without allergic diseases who underwent a general health examination between 2009 and 2015 were included. Subjects with allergic diseases exhibited a higher incidence of glaucoma compared to the control group. The hazard ratio (HR) of glaucoma onset was 1.49 and 1.39 in subjects with at least one allergic disease before and after adjusting for potential confounding factors, respectively. Among allergic diseases, atopic dermatitis showed the highest risk for glaucoma development (aHR 1.73) after adjusting for confounders. Allergic rhinitis showed an increased risk for incident glaucoma after adjustment (aHR 1.38). Asthma showed the lowest but still increased risk for glaucoma (aHR 1.22). The associations were consistent in all subgroup analyses stratified by sex, smoking, drinking, exercise, diabetes, hypertension, dyslipidemia, or history of steroid. In conclusion, allergic diseases are associated with increased risk of glaucoma development. Among allergic diseases, atopic dermatitis showed the highest risk for glaucoma development followed by allergic rhinitis and asthma.

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.

Addressing neurodegeneration in glaucoma: Mechanisms, challenges, and treatments

Glaucoma is the leading cause of irreversible blindness globally. The disease causes vision loss due to neurodegeneration of the retinal ganglion cell (RGC) projection to the brain through the optic nerve. Glaucoma is associated with sensitivity to intraocular pressure (IOP). Thus, mainstay treatments seek to manage IOP, though many patients continue to lose vision. To address neurodegeneration directly, numerous preclinical studies seek to develop protective or reparative therapies that act independently of IOP. These include growth factors, compounds targeting metabolism, anti-inflammatory and antioxidant agents, and neuromodulators. Despite success in experimental models, many of these approaches fail to translate into clinical benefits. Several factors contribute to this challenge. Firstly, the anatomic structure of the optic nerve head differs between rodents, nonhuman primates, and humans. Additionally, animal models do not replicate the complex glaucoma pathophysiology in humans. Therefore, to enhance the success of translating these findings, we propose two approaches. First, thorough evaluation of experimental targets in multiple animal models, including nonhuman primates, should precede clinical trials. Second, we advocate for combination therapy, which involves using multiple agents simultaneously, especially in the early and potentially reversible stages of the disease. These strategies aim to increase the chances of successful neuroprotective treatment for glaucoma.

Regulated Necrosis in Glaucoma: Focus on Ferroptosis and Pyroptosis

Glaucoma is one of the most common causes of irreversible blindness worldwide. This neurodegenerative disease is characterized by progressive and irreversible damage to retinal ganglion cells (RGCs) and optic nerves, which can lead to permanent loss of peripheral and central vision. To date, maintaining long-term survival of RGCs using traditional treatments, such as medication and surgery, remains challenging, as these do not promote optic nerve regeneration. Therefore, it is of great clinical and social significance to investigate the mechanisms of optic nerve degeneration in depth and find reliable targets to provide pioneering methods for the prevention and treatment of glaucoma. Regulated necrosis is a form of genetically programmed cell death associated with the maintenance of homeostasis and disease progression in vivo. An increasing body of innovative evidence has recognized that aberrant activation of regulated necrosis pathways is a common feature in neurodegenerative diseases, such as Alzheimer's, Parkinson's, and glaucoma, resulting in unwanted loss of neuronal cells and function. Among them, ferroptosis and pyroptosis are newly discovered forms of regulated cell death actively involved in the pathophysiological processes of RGCs loss and optic nerve injury. This was shown by a series of in vivo and in vitro studies, and these mechanisms have been emerging as a key new area of scientific research in ophthalmic diseases. In this review, we focus on the molecular mechanisms of ferroptosis and pyroptosis and their regulatory roles in the pathogenesis of glaucoma, with the aim of exploring their implications as potential therapeutic targets and providing new perspectives for better clinical decision-making in glaucoma treatment.

Novel artemisinin derivative P31 inhibits VEGF-induced corneal neovascularization through AKT and ERK1/2 pathways

Corneal neovascularization (CoNV)is a major cause of blindness in many ocular diseases. Substantial evidence indicates that vascular endothelial growth factor (VEGF) plays an important role in the pathogenesis of corneal neovascularization. Previous evidence showed that artemisinin may inhibit angiogenesis through down regulation of the VEGF receptors. We designed and synthesized artemisinin derivatives, and validated their inhibitory effect on neovascularization in cell and animal models, and explored the mechanisms by which they exert an inhibitory effect on CoNV. Among these derivatives, P31 demonstrated significant anti-angiogenic effects in vivo and in vitro. Besides, P31 inhibited VEGF-induced HUVECs angiogenesis and neovascularization in rabbit model via AKT and ERK pathways. Moreover, P31 alleviated angiogenic and inflammatory responses in suture rabbit cornea. In conclusion, as a novel artemisinin derivative, P31 attenuates corneal neovascularization and has a promising application in ocular diseases.

Identification of immune-related biomarkers for glaucoma using gene expression profiling

Introduction: Glaucoma, a principal cause of irreversible vision loss, is characterized by intricate optic neuropathy involving significant immune mechanisms. This study seeks to elucidate the molecular and immune complexities of glaucoma, aiming to improve our understanding of its pathogenesis. Methods: Gene expression profiles from glaucoma patients were analyzed to identify immune-related differentially expressed genes (DEGs). Techniques used were weighted gene co-expression network analysis (WGCNA) for network building, machine learning algorithms for biomarker identification, establishment of subclusters related to immune reactions, and single-sample gene set enrichment analysis (ssGSEA) to explore hub genes' relationships with immune cell infiltration and immune pathway activation. Validation was performed using an NMDA-induced excitotoxicity model and RT-qPCR for hub gene expression measurement. Results: The study identified 409 DEGs differentiating healthy individuals from glaucoma patients, highlighting the immune response's significance in disease progression. Immune cell infiltration analysis revealed elevated levels of activated dendritic cells, natural killer cells, monocytes, and immature dendritic cells in glaucoma samples. Three hub genes, CD40LG, TEK, and MDK, were validated as potential diagnostic biomarkers for high-risk glaucoma patients, showing increased expression in the NMDA-induced excitotoxicity model. Discussion: The findings propose the three identified immune-related genes (IRGs) as novel diagnostic markers for glaucoma, offering new insights into the disease's pathogenesis and potential therapeutic targets. The strong correlation between these IRGs and immune responses underscores the intricate role of immunity in glaucoma, suggesting a shift in the approach to its diagnosis and treatment.

SOX9 depletion attenuates retinal ganglion cell ferroptosis through blocking ERK/p38 signaling

BACKGROUND

Retinal ischemia-refusion (I/R) is a leading cause of irreversible blindness worldwide. This study aims to explore the regulatory role of SOX9 in retinal I/R injury, and attempts to elucidate its potential regulatory mechanism.

METHODS

Retinal I/R injury model was established in vivo, and the histological changes was examined by hematoxylin and eosin (H&E) staining and immunofluorescent assay was performed to examine SOX9 expression. Oxygenation-glucose deprivation/reoxygenation (OGD/R)-induced retinal ischemia/reperfusion (I/R) injury in 661 W cells was constructed as an in vitro cellular model of glaucoma. The production of cytokines, lactate dehydrogenase (LDH) and the antioxidant enzymes were assessed by their commercial kits. Cellular reactive oxygen species (ROS) and lipid ROS was detected using DCFH-DA and C11-BODIPY 581/591 staining, respectively. Lipid peroxidation and Fe2+ level were detected to assess the ferroptosis level. Protein expression was examined by western blot. LM22B-10, the agonist of ERK signaling, was used to pretreat 661 W cells for mechanism investigation.

RESULTS

SOX9 was aberrantly upregulated following retinal I/R injury both in vivo and in vitro. SOX9 knockdown exerted a protective role against OGD/R-triggered oxidative stress, inflammatory response and ferroptosis in 661 W cells. Further, ERK/p38 signaling was activated in 661 W cells following OGD/R induction, which was repressed by SOX9 knockdown, and the ERK signaling agonist partially counteracted the protective role of SOX9 knockdown against oxidative stress, inflammatory response and ferroptosis in OGD/R-induced 661 W cells.

CONCLUSION

Collectively, inhibiting SOX9 to block oxidative stress, inflammation and ferroptosis by inactivating ERK/p38 signaling might be effective to prevent retinal I/R injury, thereby alleviating glaucoma.

Melatonin ameliorates retinal ganglion cell senescence and apoptosis in a SIRT1-dependent manner in an optic nerve injury model

Melatonin is involved in exerting protective effects in aged-related and neurodegenerative diseases through a silent information regulator type 1 (SIRT1)-dependent pathway. However, little was known about the impact of melatonin on retinal ganglion cell (RGC) senescence and apoptosis following optic nerve crush (ONC). Thus, this study aimed to examine the effects of melatonin on RGC senescence and apoptosis after ONC and investigate the involvement of SIRT1 in this process. To study this, an ONC model was established. EX-527, an inhibitor of SIRT1, was injected intraperitoneally into mice. And melatonin was administrated abdominally into mice after ONC every day. Hematoxylin & eosin staining, retina flat-mounts and optical coherence tomography were used to evaluate the loss of retina cells/neurons. Pattern electroretinogram (p-ERG) was performed to evaluate the function of RGCs. Immunofluorescence and western blot were used to evaluate protein expression. SA-β-gal staining was employed to detect senescent cells. The results demonstrated that melatonin partially rescued the expression of SIRT1 in RGC 3 days after ONC. Additionally, melatonin administration partly rescued the decreased RGC number and ganglion cell complex thickness observed 14 days after ONC. Melatonin also suppressed ONC-induced senescence and apoptosis index. Furthermore, p-ERG showed that melatonin improved the amplitude of P50, N95 and N95/P50 following ONC. Importantly, the protective effects of melatonin were reversed when EX-527 was administered. In summary, this study revealed that melatonin attenuated RGC senescence and apoptosis through a SIRT1-dependent pathway after ONC. These findings provide valuable insights for the treatment of RGC senescence and apoptosis.

[Hyperbaric oxygen therapy and eye disease: Review of the literature]

Hyperbaric oxygen therapy consists of breathing 100% oxygen continuously or intermittently in a chamber at a pressure equal to or greater than 1.4 absolute atmospheres. Indicated for the emergency treatment of carbon monoxide poisoning and other medical-surgical pathologies such as gas embolism or necrotizing soft-tissue infections, various studies have shown a beneficial effect of hyperbaric oxygen therapy in certain ocular pathologies, notably of microcirculatory origin, such as central retinal artery occlusion or macular edema linked to retinal vein occlusions. In addition, hyperbaric oxygen might represent an alternative treatment for ocular quinine toxicity and might also be useful as an adjuvant to surgery and antibiotics in cases of periorbital necrotizing fasciitis. On the other hand, oxygen in high concentrations has toxic ocular effects due to the production of reactive oxygen derivatives.

Effect of Glucosamine on Intraocular Pressure and Risk of Developing Glaucoma

PRCIS

Glucosamine supplementation is common but can be associated with increased intraocular pressure (IOP) and could contribute to the pathogenesis of glaucoma. It may be prudent for ophthalmologists to elicit any history of glucosamine use from their patients and advise them accordingly. Further studies on the role of glucosamine in glaucoma are warranted.

BACKGROUND

The most frequently recommended slow-acting medication for osteoarthritis symptoms is glucosamine, although its effectiveness is questionable. Widely used glucosamine sulfate supplements may increase IOP.

METHODS

In the current study, we analyzed online databases such as UK Biobank, MedWatch, and FinnGen to evaluate the relationship between glucosamine and IOP and glaucoma. We included budesonide and fluticasone in the analysis for comparison since these drugs are associated with increased IOP.

RESULTS

In UK Biobank subjects, glucosamine use was associated with increased corneal compensated IOP ( P =0.002, 2-tailed t test). This was also true in subjects without glaucoma ( P =0.002, 2-tailed t test). However, no significant association between glucosamine and IOP was detected in subjects with a diagnosis of glaucoma. In MedWatch, 0.21% of subjects taking glucosamine reported glaucoma, 0.29% of subjects using budesonide reported glaucoma, and 0.22% of subjects using fluticasone reported glaucoma. In contrast, 0.08% of subjects using any other drug reported glaucoma. This variability is significant ( P <0.001, 2-tailed Fisher exact test). Data from FinnGen on the risk of primary open angle glaucoma or glaucoma in subjects using glucosamine before the diagnosis of the disease revealed a significantly increased risk for both primary open angle glaucoma (hazard ratio: 2.35) and glaucoma (hazard ratio: 1.95).

CONCLUSION

Glucosamine supplementation is common but can be associated with increased IOP and could contribute to the pathogenesis of glaucoma. It may be prudent for ophthalmologists to elicit any history of glucosamine use from their patients and advise them accordingly. Further studies on the role of glucosamine in glaucoma are warranted.

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.

Assessment of Time Lag Between Blood Flow, Retinal Nerve Fiber Layer Thickness and Visual Field Sensitivity Changes in Glaucoma

Purpose

This study investigates the temporal relationship between blood flow changes and alterations in retinal nerve fiber layer thickness (RNFLT) and mean deviation (MD) in individuals with glaucoma.

Methods

Blood flow, measured by mean blur rate in optic nerve head vessels (MBRv) and tissues (MBRt) using laser speckle flowgraphy (LSFG)-NAVI, was analyzed using structural equation models (SEMs). SEMs assessed whether the previous rate of one parameter predicted the current rate of the other parameter, adjusted for its own rate in the previous time interval. Data from 345 eyes of 174 participants were gathered from visits every six months.

Results

Rates of change of both MBRv and MBRt were significantly predicted by their own rate in the previous time interval and by the rate of change of MD in the previous time interval (P < 0.001 and P = 0.043, respectively), but not by the rate of MD in the concurrent interval (P = 0.947 and P = 0.549), implying that changes in MD precede changes in blood flow. Rates of change of RNFLT were predicted by their own previous rate and the rate of change of MBRv and MBRt in either the previous interval (P = 0.002 and P = 0.008) or the concurrent interval (P = 0.001 and P = 0.018), suggesting that MBR may change before RNFLT.

Conclusions

The evidence supports a temporal sequence where MD changes precede blood flow changes, which, in turn, may precede alterations in RNFLT.

Contact lens sensor for ocular inflammation monitoring

Contact lens sensors have been emerging as point-of-care devices in recent healthcare developments for ocular physiological condition monitoring and diagnosis. Fluorescence sensing technologies have been widely applied in contact lens sensors due to their accuracy, high sensitivity, and specificity. As ascorbic acid (AA) level in tears is closely related to ocular inflammation, a fluorescent contact lens sensor incorporating a BSA-Au nanocluster (NC) probe is developed for in situ tear AA detection. The NCs are firstly synthesized to obtain a fluorescent probe, which exhibits high reusability through the quench/recover (KMnO4/AA) process. The probe is then encapsulated with 15 wt% of poly(vinyl alcohol) (PVA) and 1.5 wt% of citric acid (CA) film, and implemented on a closed microfluidic contact lens sensing region. The laser-ablated microfluidic channel in contact lens sensors allows for tear fluid to flow through the sensing region, enabling an in-situ detection of AA. Meanwhile, a smartphone application accompanied by a customized 3D printed readout box is developed for image caption and algorism to quantitative analysis of AA levels. The contact lens sensor is tested within the readout box and the emission signal is collected through the smartphone camera at room temperature with an achieved LOD of 0.178 mmol L-1 (0.0-1.2 mmol L-1). The operational and storage lifetime is also evaluated to characterize the sensor properties and resulted in 20 h and 10 days, respectively. The reusable AA contact lens sensor is promising to lead to an alternative accessible diagnostic method for ocular inflammation in point-of-care settings.

Drug combination of topical ripasudil and brimonidine enhances neuroprotection in a mouse model of optic nerve injury

PURPOSE

To determine whether combination of topical ripasudil and brimonidine has more effective neuroprotection on retinal ganglion cells (RGCs) following injury to axons composing the optic nerve.

METHODS

Topical ripasudil, brimonidine, or mixture of both drugs were administered to adult mice after optic nerve injury (ONI). The influence of drug conditions on RGC health were evaluated by the quantifications of surviving RGCs, phosphorylated p38 mitogen-activated protein kinase (phospho-p38), and expressions of trophic factors and proinflammatory mediators in the retina.

RESULTS

Topical ripasudil and brimonidine suppressed ONI-induced RGC death respectively, and mixture of both drugs further stimulated RGC survival. Topical ripasudil and brimonidine suppressed ONI-induced phospho-p38 in the whole retina. In addition, topical ripasudil suppressed expression levels of TNFα, IL-1β and monocyte chemotactic protein-1 (MCP-1), whereas topical brimonidine increased the expression level of basic fibroblast growth factor (bFGF).

CONCLUSIONS

Combination of topical ripasudil and brimonidine may enhance RGC protection by modulating multiple signaling pathways in the retina.

Effects and potential mechanisms of exercise and physical activity on eye health and ocular diseases

In the field of eye health, the profound impact of exercise and physical activity on various ocular diseases has become a focal point of attention. This review summarizes and elucidates the positive effects of exercise and physical activities on common ocular diseases, including dry eye disease (DED), cataracts, myopia, glaucoma, diabetic retinopathy (DR), and age-related macular degeneration (AMD). It also catalogues and offers exercise recommendations based on the varying impacts that different types and intensities of physical activities may have on specific eye conditions. Beyond correlations, this review also compiles potential mechanisms through which exercise and physical activity beneficially affect eye health. From mitigating ocular oxidative stress and inflammatory responses, reducing intraocular pressure, enhancing mitochondrial function, to promoting ocular blood circulation and the release of protective factors, the complex biological effects triggered by exercise and physical activities reveal their substantial potential in preventing and even assisting in the treatment of ocular diseases. This review aims not only to foster awareness and appreciation for how exercise and physical activity can improve eye health but also to serve as a catalyst for further exploration into the specific mechanisms and key targets through which exercise impacts ocular health. Such inquiries are crucial for advancing innovative strategies for the treatment of eye diseases, thereby holding significant implications for the development of new therapeutic approaches.

Human adipose tissue-derived stem cell extracellular vesicles attenuate ocular hypertension-induced retinal ganglion cell damage by inhibiting microglia- TLR4/MAPK/NF-κB proinflammatory cascade signaling

Microglia-mediated neuroinflammatory responses are recognized as a predominant factor during high intraocular pressure (IOP)-induced retinal and optic nerve injury along with potential therapeutic targets for the disease. Our previous research indicated that mesenchymal stem cell (MSC) treatment could reduce high IOP-induced neuroinflammatory responses through the TLR4 pathway in a rat model without apparent cell replacement and differentiation, suggesting that the anti-neuroinflammatory properties of MSCs are potentially mediated by paracrine signaling. This study aimed to evaluate the anti-neuroinflammatory effect of human adipose tissue-derived extracellular vesicles (ADSC-EVs) in microbead-induced ocular hypertension (OHT) animals and to explore the underlying mechanism since extracellular vesicles (EVs) are the primary transporters for cell secretory action. The anti-neuroinflammatory effect of ADSC-EVs on LPS-stimulated BV-2 cells in vitro and OHT-induced retinal and optic nerve injury in vivo was investigated. According to the in vitro research, ADSC-EV treatment reduced LPS-induced microglial activation and the TLR4/NF-κB proinflammatory cascade response axis in BV-2 cells, such as CD68, iNOS, TNF-α, IL-6, and IL-1β, TLR4, p-38 MAPK, NF-κB. According to the in vivo data, intravitreal injection of ADSC-EVs promoted RGC survival and function, reduced microglial activation, microglial-derived neuroinflammatory responses, and TLR4/MAPK/NF-κB proinflammatory cascade response axis in the OHT mice. Our findings provide preliminary evidence for the RGC protective and microglia-associated neuroinflammatory reduction effects of ADSC-EVs by inhibiting the TLR4/MAPK/NF-κB proinflammatory cascade response in OHT mice, indicating the therapeutic potential ADSC-EVs or adjunctive therapy for glaucoma.