This study provided the first evidence of TSG-6 secreted by MSCs promoting corneal epithelial wound healing in diabetic mice through activating corneal epithelial stem/progenitor cells and accelerating M2 macrophage polarization.

PurposeTo compare the myopic progression before and during strict home confinement when coronavirus disease 2019 (COVID-19) outbreak and explore the potential influencing factors.MethodsA cross-sectional study. One hundred and fifteen myopic children (115 right eyes) who replace their frame-glasses from December 2019 to January 2020 and with complete refractive records in our hospital since myopia were involved in the study. At the beginning of the strict home confinement and after a 3-month strict home confinement during the COVID-19 pandemic, they were invited to our hospital to examine the axial length and refractive errors. And visual functions, convergence insufficiency symptom survey (CISS) scale and questionnaires were also performed. Besides, the axial length and refractive errors before the COVID-19 were got from outpatient case files. The effect of strict home confinement on myopia was assessed by comparing monthly axial elongation before COVID-19 and during strict home confinement. Spearman correlation analysis was performed to explore the correlation between potential influencing factors and myopia progression.ResultsAxial length's monthly elongation during strict home confinement was 35% higher than normal periods (0.046 vs. 0.033 mm/month, P = 0.003). The proportion of severe asthenopia doubled (P = 0.020). For myopia progression, heredity, close indoor work time and electronic products were risk factors. Besides, the protective factors were age, rest time after continuous eye usage, sleep time and distance from eye to computer screen.ConclusionsDuring COVID-19, the decline in outdoor activities and increase of exposure time to digital screens accelerated the progression of myopia by 1/3.

PURPOSE. Extended contact lens (CL) wear predisposes the wearer to Pseudomonas aeruginosa infection of the cornea, but the mechanism involved remains incompletely understood. The purpose of this study was to investigate the role of the stress hormone norepinephrine (NE) in the pathogenesis of CL-induced P. aeruginosa keratitis. METHODS. A total 195 adult C57BL/6 mice were used in this study. Corneal NE content was measured after 48 hours of sterile CL wear in mice. The effect of NE on P. aeruginosa adhesion and biofilm formation on the CL surface was examined in vitro. Moreover, mouse eyes were covered with P. aeruginosa-contaminated CLs, and either 500-μM NE was topically applied or the eyes were subconjunctivally injected with 100 μg of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) to deplete local NE. Clinical scores, neutrophil infiltration, proinflammatory cytokine levels, and bacterial load on the corneas and CLs were evaluated. RESULTS. Corneal NE content was elevated with extended CL wear in mice. In vitro, NE promoted the adhesion and biofilm formation of P. aeruginosa on the CL surface. In mice, topical application of NE aggravated P. aeruginosa infection, accompanied with increased clinical scores, neutrophil infiltration, proinflammatory cytokine expression, and bacterial burden on the corneas and CLs. However, pre-depletion of local NE with DSP-4 significantly alleviated the severity of P. aeruginosa keratitis. CONCLUSIONS. Extended CL wear elevates corneal NE content, which promotes the pathogenesis of CL-induced P. aeruginosa keratitis in mice. Targeting NE may provide a potential strategy for the treatment of CL-related corneal infection caused by P. aeruginosa.

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