Aetna considers preserved human amniotic membrane transplantation or limbal stem cell transplantation for ocular surface reconstruction medically necary in ess. Ex vivo expanded limbal stem cell treatment in limbal stem cell deficiency was first reported in 1997. Acute chemical eye injury and limbal stem cell deficiency. Cell kinetic studies show that limbal stem cells, and the cells into which they evolve, transiently amplifying cells tac remain in the so called proliferative compartment. Global consensus on definition, classification, diagnosis. Limbal stem cell therapy, specifically ex vivo expansion of. Preclinical cellbased therapy for limbal stem cell. Vigorous attempts are being made to expand limbal stem cells in culture to preserve or even enrich the stem cell population. Characteristics of limbal stem cells include a slow turnover rate, high proliferative potential, clonogenicity, expression of stem cell markers, as well as the ability to regenerate the. Limbal stem cells lsc represent a quiescent cell population with high proliferative potential, which enables efficient corneal regeneration and repair 414. Lscd leads to conjunctivalization, with corneal vascularization and opacification and.
Pdf limbal stem cell deficiency and treatment with stem. These limbal stem cells become lost or deficient in the blinding disease of limbal stem cell deficiency. The limbal stem cells lack the keratin 3 differentiation marker typical of all the rest of corneal epithelium, but does possess keratin 19. Corneal epithelial stem cells and their niche at a glance. This is a prospective, consecutive, interventional singlecenter study between april and october 2009 of. Many surgical techniques are defined according to the source of the stem cells and the carrier tissues that are used. Proteomic analysis of epitheliumdenuded human amniotic membrane as a limbal stem cell niche. In lscd, the conjunctival epithelium migrates across the limbus, resulting in loss of corneal clarity and visual impairment. Stern,1,11 yangzi tian,7 james funderburgh,4 graziella pellegrini,6 kang zhang,9,10 jeffrey l. Limbal stem cells, also known as corneal epithelial stem cells, are stem cells located in the basal epithelial layer of the corneal limbus. In the 20 years since, various protocols have been developed for the cultivation of limbal epithelial cells. Corneal renewal and repair are mediated by stem cells of the limbus, the narrow zone between the cornea and the bulbar conjunctiva. Limbal epithelial stem cells reside in the basal layer of the epithelium ep, which undulates at the limbus. Ashok sharma, rajan sharma cornea services, cornea centre, chandigarh, india abstract limbal stem cells lsc play pivotal role in corneal epithelial cell homeostasis and corneal epithelial healing.
Limbal stem cell deficiency lscd is a clinical condition characterized by damage of cornea limbal stem cells, which results in an impairment of corneal epithelium turnover and in an invasion of the cornea by the conjunctival epithelium. In these patients, the conjunctivalization of the cornea is associated with visual impairment and cornea transplantation has poor prognosis for recurrence of. Corneal graft with amniotic membrane transplantation or limbal stem cell transplantation. Comparative study of substrate free and amniotic membrane. Corneal impression cytology for the diagnosis of limbal stem cell deficiency in a dog f. Four facetoface meetings, frequent email discussions, and teleconferences were conducted since then to obtain agreement on a strategic plan and methodology from all participants after a comprehensive. To investigate the epithelial thickness in the cornea and limbus in limbal stem cell deficiency lscd by using in vivo laser scanning confocal microscopy.
This nonsulfated glycosaminoglycan plays a key role in cell proliferation, growth, survival, polarization, and differentiation. Proteomic analysis of epitheliumdenuded human amniotic. Limbal stem cell deficiency is a condition that occurs upon significant injury to the limbal epithelium, and may be the result of a variety of causes. Xs asymmetric division of limbal epithelial stem cells one daughter cell that remains in the limbus as a stem cell a second daughter cell which migrates out of the limbus into the basal corneal epithelium transient. The limbal stem cells are few in number and can be damaged by a number of di. Hyaluronanbased hydrogel scaffolds for limbal stem cell.
Cultivated limbal stem cell transplantationthe surgical technique. This can be achieved by limbal conjunctival allograft from livingrelated donors12, or keratolimbal allograft klal from cadaveric donors. The importance of these stem cells is most apparent when their numbers are decreased. Epithelial thinning in limbal stem cell deficiency. Emerging therapeutic strategies for limbal stem cell. Hyaluronan ha, also termed hyaluronic acid or hyaluronate, is a major component of the extracellular matrix. A new onset of glaucoma after limbal stem cell transplantation likely relates to the need for longterm topical steroidal therapy. Daughter transient amplifying cells tacs divide and migrate towards the central cornea arrowed to replenish the epithelium, which rests on bowmans layer bl. Regeneration of the corneal surface after an epithelial insult involves division, migration, and maturation of a specialized group of. Ula 1,2 1schepens eye research institute 2massachusetts eye and ear infirmary, harvard medical sch ool usa 1.
Corneal impression cytology for the diagnosis of limbal. Listing a study does not mean it has been evaluated by the u. The most important function of ta cells is to increase the number of differentiated progeny produced by each stem cell. Glaucoma after corneal limbal stem cell transplantation. Limbal stem cell transplantation is a surgical treatment to address lscd and restore a corneal epithelial phenotype. This constellation of features led to a decadeslong search for a bona fide lsc marker that would enable prospective lsc isolation for therapeutic. Ali,2,3,11 michael young,8 yubing xie,7 and sally temple1,11, 1neural stem cell institute, rensselaer, ny 12144, usa 2department of genetics, university college london. Restoring the cornea from limbal stem cells future medicine mouse krt12 limbal stem cells limbal stem cell deficiency limbus pax6 skin stem cell therapy transplantation. Regeneration of the corneal surface after an epithelial insult involves division, migration, and maturation of a. Limbal stem cell transplants and amniotic membrane grafts in ocular surface disease. The diverse biological roles of ha are linked to the combination of has physicochemical properties and habinding proteins. Limbal stem cells act as a barrier to conjunctival epithelial cells and normally prevent them from migrating on to the corneal surface. The condition is characterized by visual impairment and pain.
Lsc do not express markers of differentiated mature corneal epithelium 2, 15. Based on the source of cells, limbal transplant can be autologous or allogenic. Diagnosis and management of limbal stem cell deficiency t. Regenerating eye tissues to preserve and restore vision cell. To analyze the incidence, nature, outcomes, and complications of acute chemical eye injuries, including the incidence of limbal stem cell deficiency lscd and to compare the 2 main classifications for ocular chemical injuries. Identification and characterization of the limbal epithelial stem cells lescs has proven to be a major accomplishment in anterior ocular surface biology. Limbal stem cell deficiency any process or disease that results in dysfunction or loss of the limbal epithelial cells lec may result in limbal stem cell deficiency lscd 7.
Introduction the human ocular surface spans from the conjunct iva to the cornea and plays a critical role. Lescs have been demonstrated to play an important role in maintaining. Limbal epithelial and mesenchymal stem cell therapy for corneal regeneration sachin shukla a, swapna s shanbhagb, fatemeh tavakkoli, shobhit varmab, vivek singha, and sayan basua,b acenter forocularregeneration core,lv prasadeye institute,hyderabad,india. Limbal stemcell therapy and longterm corneal regeneration. Limbal stem cell deficiency lscd can develop in traumatic, immunologic, or genetic diseases that affect the ocular surface. The concept of limbal stem cell transplantation was based initially on the conjecture that it was the limbal epithelium that contained the stem cell population for corneal epithelial cellular proliferation and differentiation, which differed greatly from the conjunctival epithelium phenotype. Limbal stem cells located at limbal epithelial crypts within the limbal palisades of vogt, play a fundamental role in maintenance of the corneal epithelium through proliferation and migration of. Stem cell therapy for limbal stem cell deficiency the safety and scientific validity of this study is the responsibility of the study sponsor and investigators. A 29 yearold woman ho stevensjohnson syndrome sjs with severe ocular involvement occurring six months earlier 1097 treated with topical lubrication drops and topical antibiotics. The skin broadly consists of an interfollicular epidermis, which is a stratified, keratinising squamous epithelium, which forms a protective barrier to the outside. X vector combination of proliferation and centripetal migration of the basal epithelial cells.
These cells have the capacity to keep on dividing throughout a persons lifetime, replenishing cells that are being sloughed o. A limbal stem cell working group was first established by the cornea society in 2012. Dyskeratosis congenita and limbal stem cell deficiency. Limbal stem cell transplants and amniotic membrane grafts. Limbal stem cells lscs are essential to maintain cornea epithelium and endowed with a capacity for selfrenewal and extended proliferative potential 1,2. These cells have been shown to be a subpopulation of limbal epithelial basal cells, which serve as the progenitor population of the corneal epithelium. Holoclar for treating limbal stem cell deficiency after. Effect of transportation on cultured limbal epithelial. Limbal epithelial and mesenchymal stem cell therapy for. Corneal vascularization and opacity have been estimated to cause blindness in eight million people 10% of total blindness worldwide each year 1, and various forms of lscd contribute to this total. With a reduced ability to repopulate the corneal epithelium and an unstable ocular surface, patients with limbal stem cell deficiency lscd can have ocular pain.
Sp amniotic membrane grafting amg for a persistent epithelial defect os. Stem cells have the unique capacity to selfrenew and generate committed, transit amplifying ta progenitors that differentiate into the cell lineages of the tissue of origin niemann and watt, 2002. Unfortunately, the occurrence of glaucomatous optic neuropathy may lead to irreversible visual field loss and a compromised visual outcome after otherwise successful ocular surface transplantation. Ocular burns may destroy the limbus, causing limbal stem cell. Limbal stem cell transplantation includes reconstructive surgical procedures to restore a corneal epithelium. The culture and transplantation of human limbal stem cells. Ali,2,3,11 michael young,8 yubing xie,7 and sally temple1,11, 1neural stem cell institute, rensselaer, ny 12144, usa 2department of genetics, university college london institute of.
Pdf cultivated limbal stem cell transplantationthe. Human corneal epithelial progenitor cells,regeneration of a normal corneal surface by limbal stem cell therapy public summary. Limbal stem cell deficiency can be treated with transplantation of cultured human limbal epithelial cells lec. In these patients, the conjunctivalization of the cornea is associated with visual impairment and cornea transplantation has poor prognosis. It can be advantageous to produce lec in centralized labs and thereafter ship them. They form the border between the cornea and the sclera. Limbal epithelial stem cells of the cornea stembook.
Limbal stem cell deficiency has an important position among corneal blindness, it is the second most common cause of blindness in the worldwide. Stem cell therapy for limbal stem cell deficiency full. Limbal stem cell damage after chemical injury, autoimmune disorders or iatrogenic trauma leads to corneal conjunctivalisation with new vessel formation, epithelium instability and visual loss. Longterm outcome of keratolimbal allograft with or.