Primary open-angle glaucoma (POAG) is characterized by degeneration of retinal ganglion cells associated with an increase in intraocular pressure (IOP) due to hindered aqueous humor (AH) drainage through the trabecular meshwork and uveoscleral pathway. Polyunsaturated fatty acids and oxylipins are signaling lipids regulating neuroinflammation, neuronal survival and AH outflow. Among them, prostaglandins have been previously implicated in glaucoma and employed for its treatment. This study addressed the role of signaling lipids in glaucoma by determining their changes in AH accompanying IOP growth and progression of the disease. Eye liquids were collected from patients with POAG of different stages and cataract patients without glaucoma. Lipids were identified and quantified by UPLC-MS/MS. The compounds discriminating glaucoma groups were recognized using ANCOVA and PLS-DA statistic approaches and their biosynthetic pathways were predicted by bioinformatics. Among 22 signaling lipids identified in AH, stage/IOP-dependent alterations in glaucoma were provided by a small set of mediators, including 12,13-DiHOME, 9- and 13-HODE/KODE, arachidonic acid and lyso-PAF. These observations correlated with the expression of cytochromes P450 (CYPs) and phospholipases A2 in the ocular tissues. Interestingly, tear fluid exhibited similar lipidomic alterations in POAG. Overall, POAG may involve arachidonic acid/PAF-dependent pathways and oxidative stress as evidenced from an increase in its markers, KODEs and 12,13-DiHOME. The latter is a product of CYPs, one of which, CYP1B1, is known as POAG and primary congenital glaucoma-associated gene. These data provide novel targets for glaucoma treatment. Oxylipin content of tear fluid may have diagnostic value in POAG.

Autoimmune uveitis is a relapsing blind-causing ocular condition with complex pathogenesis that is not completely understood. There is a high demand for accurate animal models of experimental autoimmune uveitis (EAU) suitable for elucidating the molecular mechanisms of the disease and testing new therapeutic approaches. Here, we demonstrated that photoreceptor Ca²⁺/Zn²⁺-sensor protein recoverin is a uveoretinal antigen in albino rabbits provoking typical autoimmune chorioretinitis 2–4 weeks after immunization. The pathologic process in recoverin-induced EAU shared features with human disease and included lymphocytic infiltration of the retina, Dalen–Fuchs nodules and foci of subtotal or total retinal atrophy, manifested as a decrease in amplitude of the a-wave of the electroretinogram. In some cases, changes in the retinal vascular pattern and subretinal hemorrhages were also observed. These signs were accompanied by a gradual accumulation of serum antibodies against recoverin. Biochemical examination of the aqueous humor (AH) revealed typical characteristics of inflammation and oxidative stress, including increased levels of TNF-α and IL-6 and decreased levels of IL-10, as well as decreased total antioxidant activity, superoxide dismutase and glutathione peroxidase activities, and increased zinc concentration. Consistently, metabolomic and targeted lipidomic analysis of AH showed high lactate and low ascorbic acid levels in early EAU; increased levels of key pro-inflammatory signaling lipids such as PGE2, TXB2, 11-HETE and Lyso-PAF; and reduced levels of the anti-inflammatory fatty acid DHA in advanced stages of the disease. Uveitic AH became enriched with recoverin, confirming disruption of the blood–ocular barrier and photoreceptor damage. Notably, the application of mitochondria-targeted antioxidant therapy impeded EAU progression by maintaining local antioxidant activity and suppressing TNF-α, IL-6 and PGE2 signaling. Overall, our results demonstrate that recoverin-induced EAU in rabbits represents an accurate model of human autoimmune posterior uveitis and suggest new directions for its therapy that can be trialed using the developed model.

Primary open-angle glaucoma (POAG) is a frequent blindness-causing neurodegenerative disorder characterized by optic nerve and retinal ganglion cell damage most commonly due to a chronic increase in intraocular pressure. The preservation of visual function in patients critically depends on the timeliness of detection and treatment of the disease, which is challenging due to its asymptomatic course at early stages and lack of objective diagnostic approaches. Recent studies revealed that the pathophysiology of glaucoma includes complex metabolomic and proteomic alterations in the eye liquids, including tear fluid (TF). Although TF can be collected by a non-invasive procedure and may serve as a source of the appropriate biomarkers, its multi-omics analysis is technically sophisticated and unsuitable for clinical practice. In this study, we tested a novel concept of glaucoma diagnostics based on the rapid high-performance analysis of the TF proteome by differential scanning fluorimetry (nanoDSF). An examination of the thermal denaturation of TF proteins in a cohort of 311 ophthalmic patients revealed typical profiles, with two peaks exhibiting characteristic shifts in POAG. Clustering of the profiles according to peaks maxima allowed us to identify glaucoma in 70% of cases, while the employment of artificial intelligence (machine learning) algorithms reduced the amount of false-positive diagnoses to 13.5%. The POAG-associated alterations in the core TF proteins included an increase in the concentration of serum albumin, accompanied by a decrease in lysozyme C, lipocalin-1, and lactotransferrin contents. Unexpectedly, these changes were not the only factor affecting the observed denaturation profile shifts, which considerably depended on the presence of low-molecular-weight ligands of tear proteins, such as fatty acids and iron. Overall, we recognized the TF denaturation profile as a novel biomarker of glaucoma, which integrates proteomic, lipidomic, and metallomic alterations in tears, and monitoring of which could be adapted for rapid non-invasive screening of the disease in a clinical setting.

The growing prevalence of progressive myopia and its disabling consequences explains the elaboration of reliable diagnostic markers and new treatment strategies based on the research results of molecular mechanisms underlying the development of the condition. The paper reviews recent basic pathogenetic research studies which have greatly broadened the awareness of the deep causes of progressive myopia associated with the activity of certain growth factors, local and systemic protein metabolism, and regulation of hormonal and neural processes. Practical clinical guidelines for new criteria of diagnosis and control of myopia are published as they could be useful while selecting individual treatment plans including indications to sclera-strengthening therapy and its evaluation. The results may be promising in the elaboration of systemic and local medications for the prevention of myopia progression, which should address the regulation of connective tissue disorders, hormonal shifts, and imbalanced autonomic nervous system.