Oxidative Damages to Eye Stem Cells, in Response to, Bright and Ultraviolet Light, Their Associated Mechanisms, and Salvage Pathways

ROS-Mediated Fragmentation Alters the Effects of Hyaluronan on Corneal Epithelial Wound Healing

A buildup of reactive oxygen species (ROS) occurs in virtually all pathological conditions. Hyaluronan (HA) is a major extracellular matrix component and is susceptible to oxidation by reactive oxygen species (ROS), yet the precise chemical structures of oxidized HA products (oxHA) and their physiological properties remain largely unknown. This study characterized the molecular weight (MW), structures, and physiological properties of oxHA. For this, high-molecular-weight HA (HMWHA) was oxidized using increasing molar ratios of hydrogen peroxide (H2O2) or hypochlorous acid (HOCl). ROS lead to the fragmentation of HA, with the oxHA products produced by HOCl exhibiting an altered chemical structure while those produced by H2O2 do not. HMWHA promotes the viability of human corneal epithelial cells (hTCEpi), while low MWHA (LMWHA), ultra-LMWHA (ULMWHA), and most forms of oxHA do not. HMWHA and LMWHA promote hTCEpi proliferation, while ULMWHA and all forms of oxHA do not. LMWHA and some forms of oxHA promote hTCEpi migration, while HMWHA does not. Finally, all native forms of HA and oxHA produced by HOCl promote in vivo corneal wound healing, while oxHA produced by H2O2 does not. Taken together, our results show that HA fragmentation by ROS can alter the physiological activity of HA by altering its MW and structure.

Single-cell RNA sequencing in cornea research: Insights into limbal stem cells and their niche regulation

The corneal epithelium is composed of stratified squamous epithelial cells on the outer surface of the eye, which acts as a protective barrier and is critical for clear and stable vision. Its continuous renewal or wound healing depends on the proliferation and differentiation of limbal stem cells (LSCs), a cell population that resides at the limbus in a highly regulated niche. Dysfunction of LSCs or their niche can cause limbal stem cell deficiency, a disease that is manifested by failed epithelial wound healing or even blindness. Nevertheless, compared to stem cells in other tissues, little is known about the LSCs and their niche. With the advent of single-cell RNA sequencing, our understanding of LSC characteristics and their microenvironment has grown considerably. In this review, we summarized the current findings from single-cell studies in the field of cornea research and focused on important advancements driven by this technology, including the heterogeneity of the LSC population, novel LSC markers and regulation of the LSC niche, which will provide a reference for clinical issues such as corneal epithelial wound healing, ocular surface reconstruction and interventions for related diseases.

The clinical features and the factors affecting visual prognosis in pediatric open-globe ınjuries

PURPOSE

To investigate clinical features and factors affecting visual prognosis after pediatric open-globe injuries.

METHODS

Retrospective study of 223 children with open-globe injury was conducted. Children with final logMAR visual acuity (LVA) > 0.70 were determined as poor-vision group (group 1, n = 108) and those with final LVA ≤ 0.70 as good-vision group (group 2, n = 115). Demographic characteristics (age, gender, and damaged eye), time between trauma and surgery, ocular trauma score (OTS), follow-up time, injury size, initial and final visual acuity levels, injury type (penetrating injury, globe rupture, perforating injury, and intraocular foreign body injury), injury localization (zone 1 = within the corneal and/or limbal area, zone 2 = within the scleral area extending 5 mm back from the limbus, and zone 3 = within the area posterior to zone 2), injury cause [metal objects (fork, knife, needle), broken glass, blunt objects (ball, punch), pen-pencil, and unidentified objects], and accompanying ocular findings of the groups were detected, and comparisons were done. Additionally, effects of age, time between trauma and surgery, OTS, injury size, follow-up time, initial LVA, injury type, and injury zone on final LVA were analyzed in both groups.

RESULTS

Mean age was 9.1 ± 2.0 years. There were 151 males and 72 females. Compared to group 1, group 2 had better initial and final visions (1.21 ± 0.26 vs 0.60 ± 0.28, p < 0.001 for initial LVA; 1.00 ± 0.32 vs 0.30 ± 0.13, p < 0.001 for final LVA), greater OTS (1.72 ± 0.53 vs 3.73 ± 0.61, p = 0.025), and smaller injury size (10.4 ± 3.5 vs 5.8 ± 2.4 mm, p = 0.002). Globe rupture (p = 0.015) and relative afferent pupillary defect (RAPD) (p = 0.037) were higher in group 1, while penetrating injury (p = 0.044), zone 1 involvement (p = 0.038), and metal object injury (p = 0.041) were higher in group 2. Based on multivariate analysis, the presences of globe rupture (p = 0.024) and RAPD (p = 0.035), the involvement without zone 1 (p = 0.042), and the injury without metal object (fork, knife, needle) (p = 0.046) were associated with poor final vision. Final LVA (for group 1 and group 2) was negatively correlated with OTS (r =  - 0.398, p = 0.037; r =  - 0.369, p = 0.040), while positively correlated with injury size (r = 0.412, p = 0.031; r = 0.318, p = 0.046) and initial LVA (r = 0.335, p = 0.043; r = 0.402, p = 0.034).

CONCLUSION

In our study, poor prognostic factors affecting final vision were low OTS, poor initial vision, the presences of globe rupture and RAPD, the large injury size, the involvement without zone 1, and the injury without metal object (fork, knife, needle).

The Fujian eye cross sectional study: objectives, design, and general characteristics

Purpose

To describe the objective and design of the Fujian Eye Study and to introduce the general characteristics and vision condition of this study.

Methods

The Fujian Eye Study (FJES) is a population-based cross-sectional survey on the public eye health status of residents over 50 years old in the entire Fujian Province of Southern China, which contains both urban and rural areas and coastal and inland regions. 10,044 participants were enrolled using a two-stage cluster sampling design and underwent a questionnaire and a series of standard examinations both physical and ocular. The main subgroups of data collection included age, sex, region, refractive error, education background, income, eating habits, smartphone usage in the dark, complaints of eye discomfort, history of chronic diseases, consumption of tobacco, alcohol, or tea.

Results

8211 (81.8%) participants were finally included and were divided into urban populations (4678 subjects) and rural populations (3533 subjects) and coastal residents (6434 subjects) and inland residents (1777 subjects); 4836 participants were female. The mean age was 64.39 (SD 8.87) years (median 64 years; range 50–98 years). 227 (3.33%) had vision impairment (VI), 195 (2.87%) had low vision and 14 (0.21%) were blind. The mean presenting near visual acuity (PNVA) was 0.28 (0.17), the mean presenting distance visual acuity (PDVA) was 0.61 (0.30), and the mean best corrected visual acuity (BCVA) was 0.82 (0.28).

Conclusions

The FJES collected detailed questionnaire information and overall ocular and physical examinations, which provide the opportunity to identify risk factors and images of VI and eye diseases and to evaluate their associations with chronic diseases and basic personal information.

DNA targeting half sandwich Ru(ii)-p-cymene-N^N complexes as cancer cell imaging and terminating agents: influence of regioisomers in cytotoxicity

One pot green synthesis and isolation of regioisomers of a library of DNA targeting anticancer Ru(ii)-p-cymene complexes to bringforth as cancer cell imaging as well as terminating agents.

Lung damage by thoron progenies versus possible damage redemption by lung stem cells: a perspective

PURPOSE

Natural radiation is the major source of human exposure to ionizing radiation. About 52% of the total dose received from the high natural background radiations (HNBR) areas are due to inhalation dose from radon (²²²Rn)/thoron (²²⁰Rn) and their progenies. Hence, we reviewed the biological effects of ²²²Rn/²²⁰Rn and their progenies on lung tissue, and the possible role of lung stem cells in salvaging the damage caused by ²²²Rn/²²⁰Rn and their progenies.

MATERIALS AND METHOD

We have extensively reviewed articles among several hits obtained in PubMed, Scopus, and Elsevier databases with keywords 'Radon/Thoron' OR Thoron progeny/Radon progeny OR 'Thoron/Radon inhalation and lungs', and proceed for further analysis. Also, databases related to oxidative damage to lung stem cells by radiation and the repair mechanisms involved by the lung stem cells were also included.

RESULTS

Based on the existing epidemiological data on radon in residential buildings, we found that evidence exists on the association of radon induced lung carcinogenesis, but the data regarding the role of thoron induced lung damage is very limited and inconclusive. We also found that limited information has been provided based on ecological designs, leading to poor documentation of health statistics, in particular, organ-specific cancer rates. Finally, we tried to elucidate the possible mechanisms of lung injury induced by thoron inhalation and the probable role of lung stem cell toward the redemption of such oxidative damages.

CONCLUSION

Existing epidemiological data on thoron inhalation and associated health outcomes are limited and inconclusive. Further, in vivo experiments, with respect to radon/thoron inhalation dose rate ranges corresponding to the HNBR areas will be helpful in understanding the cellular and molecular effects.