Focus on limbal stem cell deficiency and limbal cell transplantation

Limbal stem cell deficiency(LSCD)causes severe vision impairment and can lead to blindness,representing one of the most challenging ocular surface disorders.Stem cell deficiency can be congenital or,more often,acquired.The categorization of ocular surface transplantation techniques is crucial to achieving treatment homogeneity and quality of care,according to the anatomic source of the tissue being transplanted,genetic source,autologous or allogenic transplantation(to reflect histocompatibility in the latter group),and cell culture and tissue engineering techniques.The aim of this minireview is to provide a summary of the management of LSCD,from clinical characteristics and therapeutic outcomes to the development of novel therapeutic approaches.The manuscript also briefly summarizes recent findings in the current literature and outlines the future challenges to overcome in the management of the major types of ocular surface failure.

Cell-based therapies for limbal stem cell deficiency: a literature review

Background and Objective:Limbal stem cell deficiency(LSCD)is characterized by the insufficiency of limbal stem cells to maintain the corneal epithelium.Severe cases of LSCD may be treated with limbal transplantation from healthy autologous or allogeneic limbal tissue.Multiple cell-based therapies have been studied as alternative treatments to improve success rates and minimize immunosuppressive regimens after allogeneic transplants.In this review,we describe the success rates,and complications of different cell-based therapies for LSCD.We also discuss each therapy’s relative strengths and weaknesses,their history in animal and human studies,and their effectiveness compared to traditional transplants.Methods:PubMed was searched for publications using the terms LSCD,cell-based therapy,cultivated limbal epithelial transplantation(CLET),cultivated oral mucosal epithelial transplantation(COMET),and mesenchymal stem cells from 1989 to August 2022.Inclusion criteria were English language articles.Exclusion criteria were non-English language articles.Key Content and Findings:current cell-based therapies for LSCD are CLET and non-limbal epithelial cells.Non-limbal epithelial cell methods include COMET,conjunctival epithelial autografts,and mesenchymal stem/stromal cells(MSCs).Moreover,several alternative potential sources of non-limbal cells have described,including induced pluripotent stem cells(iPSCs),human embryonic stem cells(hESCs),human dental pulp stem cells,hair follicle bulge-derived epithelial stem cells,amniotic membrane epithelial cells,and human umbilical cord lining epithelial cells.Conclusions:Cell-based therapies are a promising treatment modality for LSCD.While CLET is currently the only approved cell-based therapy and is only approved in the European Union,more novel methods have also been shown to be effective in human or animal studies thus far.Non-limbal epithelial cells such as COMET are also an alternative treatment to allogeneic transplants especially as a surface stabilizing procedure.iPSCs are currently being studied in early phase trials and have the potential to revolutionize the way LSCD is treated.Lastly,cell-based therapies for restoring the limbal niche such as mesenchymal stem cells have also shown promising results in the first human proof-of-concept study.Several potential sources of non-limbal cells are under investigation.

Comparison of Benefits from Different Planting Models of Ningza No.21

Ningza No.21, a new hybrid rapeseed cultivar, was used as the test mate-rial in this study. The common planting models in large-scale production （3 trans-planting models and 2 direct-seeding models） were adopted. Based on the high-yield cultivation, the yield and economic benefits of different planting models were investi-gated. ln addition, the labor costs, agricultural production materials costs and agri-cultural machinery costs of different planting model were analyzed to explore the low-costs and high-economic benefits planting model. The results showed the yields of the 5 planting models were al relatively high with average yield of 3 282.30 kg/hm2, ranging from 2 899.50 to 3 642.00 kg/hm2. Although the average yield and output value of transplanting models were higher than that of direct-seedling models by 429.25 kg/hm2 and 2 189.18 yuan/hm2 respectively, the production costs of trans-planting models were higher than that of direct-seedling model by 2 098.81 yuan/hm2 and the economic benefits were basical y equal. Among the costs of rapeseed pro-duction, the labor costs accounted for more than 60%. ln the labor costs, the har-vesting labor costs represented about 50%. Therefore, under current production con-ditions, the direct seeding and mechanized harvesting should be adopted in the rapeseed production to reduce production costs and improve economic benefits.

Effects of Seedling Cutivation with Mat-fiber Mulch on Quality and Quantity of Early-season Rice

[Objective] The aim was to explore effects of tray mat of fiber mulch on quality and yield of early rice-season rice transplanted by machine. [Method] Seedling quality, the rate of leaked rice, density of mechanical transplanting rice, mature rate and yield covered with fiber mulch were compared with groups not covered with mulch. Furthermore, different indices of cultivated rice with and without fiber mulch were analyzed and compared. [Result] The rice yield in the group with fiber mulch improved by 11.9% and rice quality enhanced as wel . What＇s more, rice plants were much easier to be col ected, and the rate of leaked rice lowered by machine. [Conclusion] The research provides theoretical references for seedling transplanting and cultivation of early-season rice by machine with tray mats.