ABSTRACT
@#The corneal epithelial cells are the outermost layer of the cornea. When they are turnover or trauma, the corneal epithelial cells are supplemented by continuous self-renewal of stem cells located in the basal epithelium at the corneoscleral limbus. If limbal stem cells are deficient(LSCD), this balance would be broken, resulting in corneal diseases. Currently, transplantation of cultured limbal stem cells is one of the best curative option of reconstruction of the ocular surface. This article reviews the recent progress on identification, different sources of stem cells, and expansion of limbal stem cells.
ABSTRACT
Limbal stem cells (LSCs),the source of corneal epithelial cells,play an important role in the ocular surface. In recent years, with the development of somatic stem cell application and tissue engineering, biomaterials and cell culture technology,progress has been made on the basic researches and clinical applications of ocular surface reconstruction with ex vivo cultured limbal epithelial and oral mucosal epithelial cell sheet transplantation. However, there are several issues, including the successful clinical outcomes for ocular surface reconstruction,and the in vivo tracking of donor stem cells,remained indefinitive. This article introduced and compared recent advancements of tissue engineering techniques ex vivo cultured autologous or allogeneic limbal,oral mucosal epithelial cells in ocular surface reconstruction,so as to provide a useful direction for the future research of ocular surface reconstruction.
ABSTRACT
Background Limbal stem cells (LSCs) play an important role on the stability of corneal epithelium and corneal transparency.Rho-associated coiled-coil containing protein kinase (ROCK) inhibitor can promote cell proliferation and reduce apoptosis,such as human embryonic stem cells and karatin epithelial cells.Objective This study was to investigate the improving effect of Y-27632,a ROCK inhibitor,on the activity of rabbit LSCs in corneal preservation medium.Methods Corneal preservation solution was prepared by adding 12.5％ chondroitin sulfate,10.0％ low molecular dextran,20.0 mg/L dexamethasone,100 mg/L tobramycin sulfate,9.5 g/L Hepes and 0.375 mg/L L-glutamine in MEM.The corneas of New Zealand white rabbits were collected and preserved in the corneal preservation solution with or without Y-27632 for 4,7,14 days,and the density and morphology of corneal endothelial cells were examined by using 0.25％ trypan blue staining and 0.2％ alizarin red staining.Isolated corneal epithelial cells were seeded on 3T3 feeder layer and cultured for 7-10 days until colonies formation.Colony shape of LSCs was observed under the light microscope,and colony-formation efficiency was analyzed after Giemsa staining by Image J software.Results The morphology and density of corneal endothelial cells were normal in the corneal preservation solution with and without Y-27632 for 4 days.In the seventh day after preservation,the cells remained the regular hexagon in shape in the preservation solution with Y-27632,however,the cellular membrane was slightly shrinking with the positive staining for alizarin red in the preservation solution without Y-27632.The density of corneal endothelial cells in the corneal preservation solution without Y-27632 was (2 262-± 75) cells /mm2,while in the preservation solution with Y-27632 was (2 425 ±95) cells/mm2(P＜0.001).The cloning spheres of LSCs were similar in preservation solution both with and without Y-27632 in the freshly isolated cornea or preserved corneas and exhibited more cells inside.But in 7 days and 14 days after preservation,the cloning spheres were much smaller in the preservation solution without Y-27632 group than those in the preservation with Y-27632 group.No significant differences were found in the cloning-formation rate and survival rate of corneal epithelial cells in corneas freshly isolated or preserved for 4 days in both groups (all at P＞0.05).In 7 days and 14 days after preservation,the active rates of corneal epitheli.al cells were (73.00±2.12)％ and (56.00±0.71)％ in the preservation solution with Y27632,which were significantly higher than (66.00 ± 4.00) ％ and (49.00 ± 0.71) ％ in the preservation solution without Y-27632,showing statistically significant differences between them (t =3.098,P =0.018;t =9.798,P =0.000).In addition,the cloning-formation rates of LSCs were (11.05±0.21)％ and (3.10±1.97)％ in the preservation solution with Y-27632 in 7 days and 14 days after preservation,revealing significantly elevation in comparison with (2.05 ± 1.20) ％ and (0.40 ±0.14) ％ in the preservation solution without Y-27632 (t =18.107,P =0.000;t=3.184,P=0.017).Conclusions Y-27632 promotes the vitality and cloning-formation ability of LSCs in corneal preservation medium,suggesting its potential use during storage of cornea.
ABSTRACT
Purpose: To compare the effectiveness of limbal relaxing incisions (LRI) with that of toric intraocular lens (IOL) implantation for the treatment of astigmatism during phacoemulsification using nonvectorial (predictability, safety, and efficacy) and vectorial analyses. Methods: This longitudinal observational case series assessed 62 eyes of 31 consecutive cataract patients with preoperative corneal astigmatism of 0.75-2.50 diopters (D) in both eyes. Patients were randomly assigned to 2 groups: a toric IOL group, which received toric IOLs in both eyes, and an LRI group, which received spherical IOLs associated with LRI placement in both eyes. All patients were evaluated at 1, 3, and 6 months after surgery, when refractive astigmatism analysis was performed using both nonvectorial and Alpins vectorial methods. Outcomes were assessed within each group and compared between groups. Results: The proportion of eyes within ±0.50 D of the intended correction at 3 and 6 months after surgery was 75% and 71.88%, respectively, in the LRI group and 40% and 66.67%, respectively, in the toric IOL group. In the remaining period, the proportion was greater in the toric IOL group. The safety index showed no difference at any time point. The efficacy index at 1 and 3 months after surgery was significantly higher in the toric IOL group (0.43 and 0.44, respectively) than in the LRI group (0.31 and 0.36, respectively). At 6 months after surgery, the status of eyes in the LRI group was as follows: 53.13% were undercorrected, 43.74% achieved the intended correction, and 3.13% were overcorrected. In the toric IOL group, 16.76% eyes were undercorrected, 76.67% achieved the intended correction, and 6.67% were overcorrected. The success rates for astigmatic surgery, astigmatism reduction at the intended axis, and astigmatism corrected were 43%, 62%, and 64%, respectively, in the LRI group and 57%, 81%, and 94%, respectively, in the toric IOL group. Conclusions: ...
Objetivo: Comparar incisões relaxantes limbares (IRL) e lentes intraoculares (LIO) tóricas tanto em termos não-vetoriais (efetividade, segurança e eficácia), quanto vetoriais no tratamento do astigmatismo por ocasião da facoemulsificação. Métodos: Estudo observacional longitudinal (série de casos) no qual foram avaliados 62 olhos de 31 pacientes consecutivos de catarata com astigmatismo corneano pré-operatório entre 0,75 e 2,50 dioptrias (D) para ambos os olhos. Os pacientes foram aleatoriamente distribuídos entre 2 grupos: "1" submetido a implante de lentes intraoculares AcrySof ToricTM em ambos os olhos e "2" com implante bilateral de lentes intraoculares tóricas AcrySof NaturalTM complementada por incisões relaxantes limbares. Todos os pacientes foram reavaliados com 1, 3 e 6 meses de pós-operatório, sendo feitas análises do astigmatismo refracional por métodos não-vetoriais, como pela análise vetorial de Alpins, interessando os resultados dentro de cada grupo e entre os grupos. Resultados: O porcentual de olhos entre ±0,50 D da correção pretendida no grupo incisões relaxantes limbares foi de 75 e 71,88%, respectivamente, em comparação aos 40 e 66,67% do grupo lentes intraoculares tóricas aos 3 e 6 meses de pós-operatório. Nos outros períodos avaliados, os porcentuais foram favoráveis ao grupo lentes intraoculares tóricas. O índice de segurança não demonstrou diferença em nenhum dos períodos. O índice de eficácia foi estatisticamente maior para o grupo lentes intraoculares tórica com 1 e 3 meses de pós-operatório (0,43 e 0,44), em comparação ao grupo incisões relaxantes limbares (0,31 e 0,36). Aos 6 meses, o porcentual de olhos, para o grupo incisões relaxantes limbares, foi: hipocorreção ...