Yu-Chien Hung

Oxidative stress has been shown to play an important role in the development of cataracts. Melatonin is an endogenous hormone that has been proposed to have a protective effect against oxidative stress; however, its association with the risk of cataracts is uncertain. This target trial emulation study aimed to investigate the relationship between the use of melatonin and the risk of cataracts using TriNetX electronic health records from 2015 to 2023. Adults aged 40 years or older who were diagnosed with a sleep disorder and initiated treatment with either melatonin or a hypnotic benzodiazepine (BZD) were included. Patients receiving hypnotic BZD therapy constituted the active comparator group. Propensity score matching (PSM) was performed to control for covariance. Exposure was defined as the initiation of melatonin or hypnotic BZD therapy. The primary outcomes were the incidence of age-related cataracts and other cataract types, assessed using Cox proportional hazards models to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). Subgroup and sensitivity analyses were conducted to reduce potential bias. After PSM, 5507 participants were included in each group. Compared with hypnotic BZD users, melatonin users were associated with a significantly lower risk of age-related cataracts (HR, 0.741; 95% CI, 0.681–0.807) and other cataracts (HR, 0.503; 95% CI, 0.433–0.584). These associations remained consistent across all subgroups and sensitivity analyses. In this target trial emulation cohort study, the use of melatonin was associated with a reduced risk of cataracts, suggesting a potential protective effect that warrants further investigation.

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the elderly, and it is characterized by oxidative stress, lipid dysregulation, and dysfunction of the retinal pigment epithelium (RPE). A hallmark of AMD is the presence of drusen, extracellular deposits rich in lipids, proteins, and cellular debris, which are secreted by the RPE. These deposits impair RPE function, promote chronic inflammation, and accelerate disease progression. Despite advancements in understanding AMD pathogenesis, therapeutic strategies targeting lipid dysregulation and oxidative damage in RPE cells remain limited. This study evaluated the effects of liraglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), on free fatty acid (FFA)-induced damage in ARPE-19 cells, a widely used in vitro model of RPE dysfunction. FFA treatment induced lipid droplet accumulation, oxidative stress, and epithelial–mesenchymal transition (EMT), which are processes implicated in AMD progression. Liraglutide significantly reduced lipid droplet accumulation, mitigated oxidative stress, and suppressed EMT, as demonstrated by high-content imaging, immunocytochemistry, and molecular assays. Mechanistic analyses revealed that liraglutide activates AMP-activated protein kinase (AMPK), enhancing lipophagy and restoring lipid homeostasis. Furthermore, liraglutide influenced exosome secretion, altering paracrine signaling and reducing EMT markers in neighboring cells. These findings underscore liraglutide’s potential to address critical mechanisms underlying AMD pathogenesis, including lipid dysregulation, oxidative stress, and EMT. This study provides foundational evidence supporting the development of GLP-1 receptor agonists as targeted therapies for AMD.

Aims: Evidence showed that SGLT2 inhibitors have greater protective effects against retinal diseases compared to other hypoglycemic agents. Thus, we explore the association between SGLT2 inhibitor usage and macular degeneration (MD) in Taiwanese patients with diabetes. Methods: The National Health Insurance (NHI) program's claim data are released as the National Health Insurance Research Database (NHIRD). This database covers more than 99% of the residents in Taiwan. We included data on patients who were newly diagnosed with type 2 diabetes mellitus (ICD-9-CM: 250, exclude 250.1x; ICD-10-CM: E11), with an age at diagnosis of over 20 years as our study population. Patients who received (sodium-glucose cotransporter 2 inhibitor) SGLT2i (ATC code: A10BK) over 90 days in 2016–2019 were defined as the SGLT2i cohort. Conversely, patients who did never received SGLT2i were defined as the non-SGLT2i cohort. The exclusion criteria were having MD before the index date, receiving SGLT2i within 1–89 days, and missing data on sex, age, or days of SGLT2i usage. Two cohorts were matched by 1:1 propensity score matching, which was based on age, sex, payroll bracket grade, urbanization, comorbidities, and medications. Results: Compared to non-SGLT2i cohort, patients who received SGLT2i had a significantly lower risk of MD (adjusted hazard ratio = 0.70, 95%CI = 0.66–0.75). Conclusions: We found that SGLT2is has a strong protective effect against MD in patients with diabetes. SGLT2is may have benefits beyond glycemic control in patients with DR. However, additional clinical and experimental studies are required.

Previous studies showed that NaIO₃ can induce oxidative stress-mediated retinal pigment epithelium (RPE) damage to simulate age-related macular degeneration (AMD). Lemon peel is rich in antioxidants and components that can penetrate the blood–retinal barrier, but their role in retinal oxidative damage remains unexplored. Here, we explore the protection of lemon peel ultrasonic-assisted water extract (LUWE), containing large amounts of flavonoids and polyphenols, against NaIO₃-induced retinal degeneration. We initially demonstrated that LUWE, orally administered, prevented retinal distortion and thinning on the inner and outer nuclei layers, downregulating cleaved caspase-3 protein expression in RPE cells in NaIO₃-induced mice. The effect of LUWE was achieved through the suppression of apoptosis and the associated proteins, such as cleaved PARP and cleaved caspase-3, as suggested by NaIO₃-induced ARPE-19 cell models. This is because LUWE reduced reactive oxygen species-mediated mitochondrial fission via regulating p-Drp-1 and Fis1 expression. We further confirmed that LUWE suppresses the expression of p-MEK-1/2 and p-ERK-1/2 in NaIO₃-induced ARPE-19 cells, thereby providing the protection described above, which was confirmed using PD98059 and U0126. These results indicated that LUWE prevents mitochondrial oxidative stress-mediated RPE damage via the MEK/ERK pathway. Elucidation of the molecular mechanism may provide a new protective strategy against retinal degeneration.

Extracellular vesicles (EVs) are secreted by various cells in the body fluid system and have been found to influence vessel formation and inflammatory responses in a variety of diseases. However, which EVs and their subtypes are involved in vascular retinal diseases is still unclear. Therefore, the aim of this study was to explore the particle distribution of EVs in retinal neovascular diseases, including age-related macular degeneration, polypoidal choroidal vasculopathy, and central retinal vein occlusion. The aqueous humor was harvested from 20 patients with different retinal neovascular diseases and six patients with cataracts as the control group. The particle distribution was analyzed using nanoparticle tracking analysis (NTA) and transmitting electron microscopy (TEM). The results revealed that the disease groups had large amounts of EVs and their subtypes compared to the control group. After isolating exosomes, a higher expression of CD81⁺ exosomes was shown in the disease groups using flow cytometry. The exosomes were then further classified into three subtypes of exomeres, small exosomes, and large exosomes, and their amounts were shown to differ depending on the disease type. To the best of our knowledge, this is the first study to elucidate the dynamics of EVs in retinal neovascular diseases using clinical cases. Our findings demonstrated the possible functionality of microvesicles and exosomes, indicating the potential of exosomes in the diagnosis and therapy of retinal neovascular diseases.