A narrative review of limbal stem cell deficiency&severe ocular surface disease

Background and Objective:Limbal stem cell deficiency(LSCD)describes the clinical condition when there is dysfunction of the corneal epithelial stem/progenitor cells and the inability to sustain the normal homeostasis of the corneal epithelium.The limbal stem cells are located in a specialized area of the eye called the palisades of Vogt(POV).There have been significant advances in the diagnosis and management of LSCD over the past decade and this review focuses on the pathophysiology of LSCD,its clinical manifestations,diagnosis,and causes.Methods:Papers regarding LSCD were searched using PubMed to identify the current state of diagnosis and causes of LSCD published through to June 2022.Key Content and Findings:LSCD is clinically demonstrated by a whorl-epitheliopathy,loss of the POV,and conjunctivalization of the cornea.The diagnosis of this condition is based on clinical examination and aided by the use of impression cytology,in vivo confocal microscopy,and anterior segment optical coherence tomography(asOCT).There are many causes of LSCD,but those which are most common include chemical injuries,aniridia,contact lens wear,and Stevens-Johnson syndrome(SJS).Conclusions:While this condition is most commonly encountered by corneal specialists,it is important that other ophthalmologists recognize the possibility of LSCD as it may arise in other co-morbid eye conditions.

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.

腹腔镜电针Vater壶腹戳孔导管扩张术和Oddi括约肌切开术14例报告

目的 :探讨LSCD和LST治疗Oddi括约肌狭窄的手术方法。方法 :乳头内口戳孔和导管扩张后 ,紧贴导管左缘 ,电针沿导管走行扩大切口 ,切开满意后 ,根据胆总管下端通畅程度选择即时缝合胆管切口或T形管引流。结果 :1 4例手术均获成功 (狭窄切开满意、引流通畅、黄疸消退 )。无胆漏、出血、肠穿孔和胰腺炎。术后 2～ 7d拔除腹腔引流管 ,术后 3～ 1 2d出院。本组平均手术时间 1 60min。结论 :选择合适病人 ,采用LSCD和LST治疗Oddi括约肌狭窄这一术式有效。

Limbal epithelial stem cells in corneal surface reconstruction

Cornea serves as the partial front barrier and major light reflection organ of the eye.The integrity of corneal surface is essential for ocular function.Injuries or congenital diseases could significantly destruct the homeostasis of the ocular surface,especially the microenvironment of limbal epithelial stem cells(LESCs),and will eventually cause dysfunction of corneal regeneration and diminish of LESCs.The loss of LESCs by different reasons are named limbal stem cell deficiency(LSCD),which is one of the leading cause of vision loss worldwide.To restore the corneal surface,LESC transplantation in the form of tissue or cell cultures is currently a viable and promising method to treat LSCD.In this review,we aim to introduce the characters and niche of LESCs,and discuss different aspects of its application in cornea surface reconstruction.