Glycogene Expression Profile of Human Limbal Epithelial Cells with Distinct Clonogenic Potential

Glycans function as valuable markers of stem cells but also regulate the ability of these cells to self-renew and differentiate. Approximately 2% of the human genome encodes for proteins that are involved in the biosynthesis and recognition of glycans. In the present study, we evaluated the expression of a small subset of glycogenes in human limbal epithelial cells with distinct clonogenic potential. Individual clones were classified as abortive or clonogenic, based on the fraction of the terminal colonies produced; clones leading exclusively to terminal colonies were referred to as abortive while those with half or fewer terminal colonies were referred to as clonogenic. An analysis of glycogene expression in clonogenic cultures revealed a high content of transcripts regulating the galactose and mannose metabolic pathways. Abortive clones were characterized by increased levels of GCNT4 and FUCA2, genes that are responsible for the branching of mucin-type O-glycans and the hydrolysis of fucose residues on N-glycans, respectively. The expansion of primary cultures of human limbal epithelial cells for 10 days resulted in stratification and a concomitant increase in MUC16, GCNT4 and FUCA2 expression. These data indicate that the clonogenic potential of human limbal epithelial cells is associated with specific glycosylation pathways. Mucin-type O-glycan branching and increased fucose metabolism are linked to limbal epithelial cell differentiation

Alleviation of Endoplasmic Reticulum Stress Enhances Human Corneal Epithelial Cell Viability under Hyperosmotic Conditions

Tear hyperosmolarity plays an essential role in the initiation and progression of dry-eye disease. Under a hyperosmotic environment, corneal epithelial cells experience perturbations in endoplasmic reticulum function that can lead to proinflammatory signaling and apoptosis. In this study, we investigated the effect of tauroursodeoxycholic acid (TUDCA), a chemical chaperone known to protect against endoplasmic reticulum stress, on corneal epithelial cells exposed to hyperosmotic conditions. We found that the expression of the genes involved in the activation of the unfolded protein response and the pro-apoptotic transcription factor DDIT3 were markedly upregulated in patients with Sjögren’s dry-eye disease and in a human model of corneal epithelial differentiation following treatment with hyperosmotic saline. Experiments in vitro demonstrated that TUDCA prevented hyperosmotically induced cell death by reducing nuclear DNA fragmentation and caspase-3 activation. TUDCA supplementation also led to the transcriptional repression of CXCL8 and IL5, two inflammatory mediators associated with dry-eye pathogenesis. These studies highlight the role of hyperosmotic conditions in promoting endoplasmic reticulum stress in the cornea and identify TUDCA as a potential therapeutic agent for the treatment of dry-eye disease

Pediatric Eye Injuries by Hydroalcoholic Gel in the Context of the Coronavirus Disease 2019 Pandemic

International audienceImportance: The coronavirus disease 2019 (COVID-19) pandemic has made alcohol-based hand sanitizers (ABHS) widely available in public places. This may warrant determining whether cases of unintentional ocular exposure are increasing, especially in children.Objective: To describe the epidemiologic trend of pediatric eye exposures to ABHS and to report the severity of the ocular lesions.Design, setting, and participants: Retrospective case series conducted from April 1, 2020, to August 24, 2020. Cases were retrieved from the national database of the French Poison Control Centers (PCC) and from a pediatric ophthalmology referral hospital in Paris, France. Cases of ocular exposure to chemical agents in children younger than 18 years during the study period were reviewed. Cases of ABHS exposure were included.Exposures: The following data were collected: age, sex, circumstances of exposure, symptoms, size of the epithelial defect at first examination, time between the incident and re-epithelialization, and medical and/or surgical management.Main outcomes and measures: Comparison of the number of eye exposures to ABHS in children between April to August 2020 and April to August 2019.Results: Between April 1 and August 24, 2020, there were 7 times more pediatric cases of ABHS eye exposures reported in the PCC database compared with the same period in 2019 (9.9% of pediatric eye exposures in 2020 vs 1.3% in 2019; difference, 8.6%; 95% CI, 7.4-9.9; P < .001). The number of cases occurring in public places increased in 2020 (from 16.4% in May to 52.4% in August). Similarly, admissions to the eye hospital for ABHS exposure increased at the same period (16 children in 2020 including 10 boys; mean [SD] age, 3.5 [1.4] years vs 1 boy aged 16 months in 2019). Eight of them presented with a corneal and/or conjunctival ulcer, involving more than 50% of the corneal surface for 6 of them. Two cases required amniotic membrane transplant.Conclusions and relevance: These data support the likelihood of an increasing number of unintentional ocular exposures to ABHS in the pediatric population. To maintain good public compliance with hand disinfection, these findings support that health authorities should ensure the safe use of these devices and warn the parents and caregivers about their potential danger for children

Pediatric eye injuries related to public location of alcohol-based hand sanitizers during the first pandemic COVID-19 context: French Poison Control Centers data

International audienceImportance The coronavirus disease 2019 (COVID-19) pandemic has made alcohol-based hand sanitizers (ABHS) widely available in public places. This may warrant determining whether cases of unintentional ocular exposure are increasing, especially in children.Objective To describe the epidemiologic trend of pediatric eye exposures to ABHS and to report the severity of the ocular lesions.Design, Setting, and Participants Retrospective case series conducted from April 1, 2020, to August 24, 2020. Cases were retrieved from the national database of the French Poison Control Centers (PCC) and from a pediatric ophthalmology referral hospital in Paris, France. Cases of ocular exposure to chemical agents in children younger than 18 years during the study period were reviewed. Cases of ABHS exposure were included.Exposures The following data were collected: age, sex, circumstances of exposure, symptoms, size of the epithelial defect at first examination, time between the incident and re-epithelialization, and medical and/or surgical management.Main Outcomes and Measures Comparison of the number of eye exposures to ABHS in children between April to August 2020 and April to August 2019.Results Between April 1 and August 24, 2020, there were 7 times more pediatric cases of ABHS eye exposures reported in the PCC database compared with the same period in 2019 (9.9% of pediatric eye exposures in 2020 vs 1.3% in 2019; difference, 8.6%; 95% CI, 7.4-9.9; P < .001). The number of cases occurring in public places increased in 2020 (from 16.4% in May to 52.4% in August). Similarly, admissions to the eye hospital for ABHS exposure increased at the same period (16 children in 2020 including 10 boys; mean [SD] age, 3.5 [1.4] years vs 1 boy aged 16 months in 2019). Eight of them presented with a corneal and/or conjunctival ulcer, involving more than 50% of the corneal surface for 6 of them. Two cases required amniotic membrane transplant.Conclusions and Relevance These data support the likelihood of an increasing number of unintentional ocular exposures to ABHS in the pediatric population. To maintain good public compliance with hand disinfection, these findings support that health authorities should ensure the safe use of these devices and warn the parents and caregivers about their potential danger for children