Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Glaucoma and the ocular renin-angiotensin-aldosterone system: Update on molecular signalling and treatment perspectives

Glaucoma, a leading cause of blindness worldwide, encompasses a group of pathological conditions affecting the optic nerve and is characterized by progressive retinal ganglion cell loss, cupping of the optic nerve head, and distinct visual field defects. While elevated intraocular pressure (IOP) is the main risk factor for glaucoma, many patients do not have elevated IOP. Consequently, other risk factors, such as ocular blood flow abnormalities and immunological factors, have been implicated in its pathophysiology. Traditional therapeutic strategies primarily aim to reduce IOP, but there is growing interest in developing novel treatment approaches to improve disease management and reduce the high rates of severe visual impairment. In this context, targeting the ocular renin-angiotensin-aldosterone system (RAAS) has been found as a potential curative strategy. The RAAS contributes to glaucoma development through key effectors such as prorenin, angiotensin II, and aldosterone. Recent evidence has highlighted the potential of using RAAS modulators to combat glaucoma, yielding encouraging results. Our study aims to explore the molecular pathways linking the ocular RAAS and glaucoma, summarizing recent advances that elucidate the role of the RAAS in triggering oxidative stress, inflammation, and remodelling in the pathogenesis of glaucoma. Additionally, we will present emerging therapeutic approaches that utilize RAAS modulators and antioxidants to slow the progression of glaucoma.

Osthole exhibits the remedial potential for polycystic ovary syndrome mice through Nrf2-Foxo1-GSH-NF-κB pathway

Polycystic ovary syndrome (PCOS) is the primary cause of female infertility with a lack of universal therapeutic regimen. Although osthole exhibits numerous pharmacological activities in treating various diseases, its therapeutic effect on PCOS is undiscovered. The present study found that application of osthole improved the symptoms of PCOS mice through preventing ovarian granulosa cells (GCs) production of more estrogen and alleviating the liberation of pro-inflammatory cytokine interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha. Meanwhile, osthole enhanced ovarian antioxidant capacity and alleviated intracellular reactive oxygen species (ROS) accumulation with a concurrent attenuation for oxidative stress, while intervention of antioxidant enzymic activity and glutathione (GSH) synthesis neutralized the salvation of osthole on GCs secretory disorder and chronic inflammation. Further analysis revealed that osthole restored the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and forkhead box O 1 (Foxo1) whose repression antagonized the amelioration of osthole on the insufficiency of antioxidant capacity and accumulation of ROS. Moreover, Nrf2 served as an intermedium to mediate the regulation of osthole on Foxo1. Additionally, osthole restricted the phosphorylation of IκBα and nuclear factor kappa B (NF-κB) subunit p65 by DHEA and weakened the transcriptional activity of NF-κB, but this effectiveness was abrogated by the obstruction of Nrf2 and Foxo1, whereas adjunction of GSH renewed the redemptive effect of osthole on NF-κB whose activation caused an invalidation of osthole in rescuing the aberration of GCs secretory function and inflammation response. Collectively, osthole might relieve the symptoms of PCOS mice via Nrf2-Foxo1-GSH-NF-κB pathway.

Achyranthis radix Extract Enhances Antioxidant Effect of Placenta-Derived Mesenchymal Stem Cell on Injured Human Ocular Cells

Age-related ocular diseases such as age-related macular degeneration, glaucoma, and diabetic retinopathy are major causes of irreversible vision impairment in the elderly. Conventional treatments focus on symptom relief and disease slowdown, often involving surgery, but fall short of providing a cure, leading to substantial vision loss. Regenerative medicine, particularly mesenchymal stem cells (MSCs), holds promise for ocular disease treatment. This study investigates the synergistic potential of combining placenta-derived MSCs (PD-MSCs) with Achyranthis radix extract (ARE) from Achyranthes japonica to enhance therapeutic outcomes. In a 24-h treatment, ARE significantly increased the proliferative capacity of PD-MSCs and delayed their senescence (* p < 0.05). ARE also enhanced antioxidant capabilities and increased the expression of regeneration-associated genes in an in vitro injured model using chemical damages on human retinal pigment epithelial cell line (ARPE-19) (* p < 0.05). These results suggest that ARE-primed PD-MSC have the capability to enhance the activation of genes associated with regeneration in the injured eye via increasing antioxidant properties. Taken together, these findings support the conclusion that ARE-primed PD-MSC may serve as an enhanced source for stem cell-based therapy in ocular diseases.

Role of inflammation in a rat model of radiation retinopathy

Radiation retinopathy (RR) is a major side effect of ocular tumor treatment by plaque brachytherapy or proton beam therapy. RR manifests as delayed and progressive microvasculopathy, ischemia and macular edema, ultimately leading to vision loss, neovascular glaucoma, and, in extreme cases, secondary enucleation. Intravitreal anti-VEGF agents, steroids and laser photocoagulation have limited effects on RR. The role of retinal inflammation and its contribution to the microvascular damage occurring in RR remain incompletely understood. To explore cellular and vascular events after irradiation, we analyzed their time course at 1 week, 1 month and 6 months after rat eyes received 45 Gy X-beam photons. Müller glial cells, astrocytes and microglia were rapidly activated, and these markers of retinal inflammation persisted for 6 months after irradiation. This was accompanied by early cell death in the outer retina, which persisted at later time points, leading to retinal thinning. A delayed loss of small retinal capillaries and retinal hypoxia were observed after 6 months, indicating inner blood‒retinal barrier (BRB) alteration but without cell death in the inner retina. Moreover, activated microglial cells invaded the entire retina and surrounded retinal vessels, suggesting the role of inflammation in vascular alteration and in retinal cell death. Radiation also triggered early and persistent invasion of the retinal pigment epithelium by microglia and macrophages, contributing to outer BRB disruption. This study highlights the role of progressive and long-lasting inflammatory mechanisms in RR development and demonstrates the relevance of this rat model to investigate human pathology.

Mucoadhesive phenylboronic acid-grafted carboxymethyl cellulose hydrogels containing glutathione for treatment of corneal epithelial cells exposed to benzalkonium chloride

Benzalkonium chloride (BAK) is the most commonly-used preservative in topical ophthalmic medications that may cause ocular surface inflammation associated with oxidative stress and dry eye syndrome. Glutathione (GSH) is an antioxidant in human tears and able to decrease the proinflammatory cytokine release from cells and reactive oxygen species (ROS) formation. Carboxymethyl cellulose (CMC), a hydrophilic polymer, is one of most commonly used artificial tears and can promote the corneal epithelial cell adhesion, migration and re-epithelialization. However, most of commercial artificial tears provide only temporary relief of irritation symptoms and show the short-term treatment effects. In the study, 3-aminophenylboronic acid was grafted to CMC for increase of mucoadhesive properties that might increase the precorneal retention time and maintain the effective therapeutic concentration on the ocular surface. CMC was modified with different degree of substitution (DS) and characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Phenylboronic acid (PBA)-grafted CMC hydrogels have interconnected porous structure and shear thinning behavior. Modification of CMC with high DS (H-PBA-CMC) shows the strong bioadhesive force. The optimal concentration of GSH to treat corneal epithelial cells (CECs) was evaluated by cell viability assay. H-PBA-CMC hydrogels could sustained release GSH and decrease the ROS level. H-PBA-CMC hydrogels containing GSH shows the therapeutic effects in BAK-damaged CECs via improvement of inflammation, apoptosis and cell viability. After topical administration of developed hydrogels, there was no ocular irritation in rabbits. These results suggested that PBA-grafted CMC hydrogels containing GSH might have potential applications for treatment of dry eye disease.

Myclobutanil induces cardiotoxicity in developing zebrafish larvae by initiating oxidative stress and apoptosis: The protective role of curcumin

Myclobutanil (MYC) is a common triazole fungicide widely applied in agriculture. MYC extensively exists in the natural environment and can be detected in organisms. However, little is known about MYC-induced embryonic developmental damage. This study aimed to unravel the cardiotoxicity of MYC and the underlying mechanisms, as well as the cardioprotective effect of curcumin (CUR, an antioxidant polyphenol) using the zebrafish model. Here, zebrafish embryos were exposed to MYC at concentrations of 0, 0.5, 1 and 2 mg/L from 4 to 96 h post fertilization (hpf) and cardiac development was assessed. As results, MYC reduced the survival and hatching rate, body length and heart rate, but increased the malformation rate and spontaneous movement. MYC caused abnormal cardiac morphology and function in myl7:egfp transgenic zebrafish, and downregulated cardiac developmental genes. MYC promoted oxidative stress through excessive reactive oxygen species (ROS) accumulation and suppressed the activities of antioxidant enzymes, triggering cardiomyocytic apoptosis via upregulated expression of apoptosis-related genes. These adverse toxicities could be significantly ameliorated by the antioxidant properties of CUR, indicating that CUR rescued MYC-induced cardiotoxicity by inhibiting oxidative stress and apoptosis. Overall, our study revealed the potential mechanisms of oxidative stress and apoptosis in MYC-induced cardiotoxicity in zebrafish and identified the cardioprotection of CUR in this pathological process.

Diabetic Retinopathy: New Treatment Approaches Targeting Redox and Immune Mechanisms

Diabetic retinopathy (DR) represents a severe complication of diabetes mellitus, characterized by irreversible visual impairment resulting from microvascular abnormalities. Since the global prevalence of diabetes continues to escalate, DR has emerged as a prominent area of research interest. The development and progression of DR encompass a complex interplay of pathological and physiological mechanisms, such as high glucose-induced oxidative stress, immune responses, vascular endothelial dysfunction, as well as damage to retinal neurons. Recent years have unveiled the involvement of genomic and epigenetic factors in the formation of DR mechanisms. At present, extensive research explores the potential of biomarkers such as cytokines, molecular and cell therapies, antioxidant interventions, and gene therapy for DR treatment. Notably, certain drugs, such as anti-VEGF agents, antioxidants, inhibitors of inflammatory responses, and protein kinase C (PKC)-β inhibitors, have demonstrated promising outcomes in clinical trials. Within this context, this review article aims to introduce the recent molecular research on DR and highlight the current progress in the field, with a particular focus on the emerging and experimental treatment strategies targeting the immune and redox signaling pathways.

Oxidative Stress in Military Missions-Impact and Management Strategies: A Narrative Analysis

This narrative review comprehensively examines the impact of oxidative stress on military personnel, highlighting the crucial role of physical exercise and tailored diets, particularly the ketogenic diet, in minimizing this stress. Through a meticulous analysis of the recent literature, the study emphasizes how regular physical exercise not only enhances cardiovascular, cognitive, and musculoskeletal health but is also essential in neutralizing the effects of oxidative stress, thereby improving endurance and performance during long-term missions. Furthermore, the implementation of the ketogenic diet provides an efficient and consistent energy source through ketone bodies, tailored to the specific energy requirements of military activities, and significantly contributes to the reduction in reactive oxygen species production, thus protecting against cellular deterioration under extreme stress. The study also underlines the importance of integrating advanced technologies, such as wearable devices and smart sensors that allow for the precise and real-time monitoring of oxidative stress and physiological responses, thus facilitating the customization of training and nutritional regimes. Observations from this review emphasize significant variability among individuals in responses to oxidative stress, highlighting the need for a personalized approach in formulating intervention strategies. It is crucial to develop and implement well-monitored, personalized supplementation protocols to ensure that each member of the military personnel receives a regimen tailored to their specific needs, thereby maximizing the effectiveness of measures to combat oxidative stress. This analysis makes a valuable contribution to the specialized literature, proposing a detailed framework for addressing oxidative stress in the armed forces and opening new directions for future research with the aim of optimizing clinical practices and improving the health and performance of military personnel under stress and specific challenges of the military field.

Aging in Ocular Blood Vessels: Molecular Insights and the Role of Oxidative Stress

Acknowledged as a significant pathogenetic driver for numerous diseases, aging has become a focal point in addressing the profound changes associated with increasing human life expectancy, posing a critical concern for global public health. Emerging evidence suggests that factors influencing vascular aging extend their impact to choroidal and retinal blood vessels. The objective of this work is to provide a comprehensive overview of the impact of vascular aging on ocular blood vessels and related diseases. Additionally, this study aims to illuminate molecular insights contributing to vascular cell aging, with a particular emphasis on the choroid and retina. Moreover, innovative molecular targets operating within the domain of ocular vascular aging are presented and discussed.

Potential New Target for Dry Eye Disease-Oxidative Stress

Dry eye disease (DED) is a multifactorial condition affecting the ocular surface. It is characterized by loss of tear film homeostasis and accompanied by ocular symptoms that may potentially result in damage to the ocular surface and even vision loss. Unmodifiable risk factors for DED mainly include aging, hormonal changes, and lifestyle issues such as reduced sleep duration, increased screen exposure, smoking, and ethanol consumption. As its prevalence continues to rise, DED has garnered considerable attention, prompting the exploration of potential new therapeutic targets. Recent studies have found that when the production of ROS exceeds the capacity of the antioxidant defense system on the ocular surface, oxidative stress ensues, leading to cellular apoptosis and further oxidative damage. These events can exacerbate inflammation and cellular stress responses, further increasing ROS levels and promoting a vicious cycle of oxidative stress in DED. Therefore, given the central role of reactive oxygen species in the vicious cycle of inflammation in DED, strategies involving antioxidants have emerged as a novel approach for its treatment. This review aims to enhance our understanding of the intricate relationship between oxidative stress and DED, thereby providing directions to explore innovative therapeutic approaches for this complex ocular disorder.

Dental caries as a health risk for visual acuity in relation to salivary transforming growth factor beta-1 among students aged 8-10 years: A cross-sectional study

Background

Dental caries and an impairment in visual acuity (VA) may both be caused by a variety of risk factors. Various conditions of the eye can appear as a consequence of overall inflammation and active dental caries.

Aim

The present study aims to assess dental caries and salivary status by measuring the transforming growth factor beta-1 (TGF-β1) and flow rate between visually impaired students compared with students with normal vision.

Materials and Methods

Research was performed employing a cross-sectional comparative study design conducted among representative 653 students aged 8-10 years at primary schools in Al-Diwaniyah governorate using the Snellen E chart for measuring VA status. Partitioning the students according to the degree of VA into normal students with normal VA of 6/9 or better and students with visual impairment of 6/12 or worse was done. Sub-sample of 180 students was recruited randomly from both groups, age and gender-matched participants for salivary analysis, and dental caries assessment measured by decay, missed, filled index, according to the World Health Organization in 2013.

Results

Out of 653 students, only 70 students suffer from a decrease in VA. Dental caries was more prevalent in those who had a decrease in VA compared with normal groups. For primary teeth decay, missed, filled teeth index (DMFT/dmft), the result was not significant but highly significant for DMFT/dmft. A significant decrease in salivary flow rate and increased salivary TGF-β1 level among visually impaired students was found.

Conclusions

According to the current research, the study population that has impaired VA, dental health status has greatly deteriorated.

Occupational Health Challenges for Aviation Workers Amid the Changing Climate: A Narrative Review

Although there are many forecasts regarding the impact of climate change on the aviation sector, a critical but frequently neglected dimension is the occupational safety risks faced by aviation professionals. This narrative review explores the potential impacts of the changing climate on the health and safety of aviation personnel. Furthermore, we examine the significance of resilience in helping these workers adapt and effectively manage climate-related challenges in their professional lives. Climate change poses increasing threats to the well-being of flight personnel through elevated temperatures, heightened ultraviolet radiation exposure, increased mental workload from extreme weather events, and other psychological stressors. Building resilience through workforce training, planning, and adaptation can reduce vulnerability. In future research, the iterative process of selecting measurement components to gauge the impact of climate change should balance feasibility, relevance for stakeholders, and accurately capturing exposure effects. For instance, while salivary cortisol measures stress biologically, assessments of depression or burnout may provide more nuanced insights on pilot health for industry decision-makers managing climate impacts. In conclusion, a strategic emphasis on enhancing the physical and psychological well-being of the aviation workforce is imperative for facilitating a more efficient adaptation within the sector. This is of paramount importance, considering the critical function that aviation serves in fostering human connectivity. Consequently, it is essential for regulatory bodies and policymakers to prioritize the safeguarding of employee health in the face of climate change challenges.

Targeting Metabolic Diseases: The Role of Nutraceuticals in Modulating Oxidative Stress and Inflammation

The escalating prevalence of metabolic and cardiometabolic disorders, often characterized by oxidative stress and chronic inflammation, poses significant health challenges globally. As the traditional therapeutic approaches may sometimes fall short in managing these health conditions, attention is growing toward nutraceuticals worldwide; with compounds being obtained from natural sources with potential therapeutic beneficial effects being shown to potentially support and, in some cases, replace pharmacological treatments, especially for individuals who do not qualify for conventional pharmacological treatments. This review delves into the burgeoning field of nutraceutical-based pharmacological modulation as a promising strategy for attenuating oxidative stress and inflammation in metabolic and cardiometabolic disorders. Drawing from an extensive body of research, the review showcases various nutraceutical agents, such as polyphenols, omega-3 fatty acids, and antioxidants, which exhibit antioxidative and anti-inflammatory properties. All these can be classified as novel nutraceutical-based drugs that are capable of regulating pathways to mitigate oxidative-stress- and inflammation-associated metabolic diseases. By exploring the mechanisms through which nutraceuticals interact with oxidative stress pathways and immune responses, this review highlights their potential to restore redox balance and temper chronic inflammation. Additionally, the challenges and prospects of nutraceutical-based interventions are discussed, encompassing bioavailability enhancement, personalized treatment approaches, and clinical translation. Through a comprehensive analysis of the latest scientific reports, this article underscores the potential of nutraceutical-based pharmacological treatment modulation as a novel avenue to fight oxidative stress and inflammation in the complex landscape of metabolic disorders, particularly accentuating their impact on cardiovascular health.

Retinopathy of Prematurity-Targeting Hypoxic and Redox Signaling Pathways

Retinopathy of prematurity (ROP) is a proliferative vascular ailment affecting the retina. It is the main risk factor for visual impairment and blindness in infants and young children worldwide. If left undiagnosed and untreated, it can progress to retinal detachment and severe visual impairment. Geographical variations in ROP epidemiology have emerged over recent decades, attributable to differing levels of care provided to preterm infants across countries and regions. Our understanding of the causes of ROP, screening, diagnosis, treatment, and associated risk factors continues to advance. This review article aims to present the pathophysiological mechanisms of ROP, including its treatment. Specifically, it delves into the latest cutting-edge treatment approaches targeting hypoxia and redox signaling pathways for this condition.

Diabetic Keratopathy: Redox Signaling Pathways and Therapeutic Prospects

Diabetes mellitus, the most prevalent endocrine disorder, not only impacts the retina but also significantly involves the ocular surface. Diabetes contributes to the development of dry eye disease and induces morphological and functional corneal alterations, particularly affecting nerves and epithelial cells. These changes manifest as epithelial defects, reduced sensitivity, and delayed wound healing, collectively encapsulated in the context of diabetic keratopathy. In advanced stages of this condition, the progression to corneal ulcers and scarring further unfolds, eventually leading to corneal opacities. This critical complication hampers vision and carries the potential for irreversible visual loss. The primary objective of this review article is to offer a comprehensive overview of the pathomechanisms underlying diabetic keratopathy. Emphasis is placed on exploring the redox molecular pathways responsible for the aberrant structural changes observed in the cornea and tear film during diabetes. Additionally, we provide insights into the latest experimental findings concerning potential treatments targeting oxidative stress. This endeavor aims to enhance our understanding of the intricate interplay between diabetes and ocular complications, offering valuable perspectives for future therapeutic interventions.