Limbal Autograft Transplantation Research Articles

Anterior Segment Optical Coherence Tomography Study of Pterygium in Conjunctival - Limbal Autograft Transplantation


 Introduction: Progressive, gradual, non-malignant proliferation of fibro-vascular tissue, occurring due to repetitive limbal stem-cell irritation & neovascularization, is referred to as pterygium. It is widespread in equatorial regions of the world, with a prevalence of 22% over a well defined ‘pterygium belt’. pterygium excision leaving bare sclera leads to the re occurrence, where as supplementing bare sclera with conjunctival autograft reduces the recurrence up-to 6%. Objective: Assessment of pterygium thickness pre-operative ly & post-surgery keratectomy area along with graft thickness after conjunctival limbal autograft transplantation (CLAT) surgery by anterior segment optical coherence tomography (AS- OCT). Method: 50 patients with primary pterygium were distributed age wise in 4 groups of 20-39, 40-59, 60-79 & 80-99 years. Anterior segment imaging was performed with RT-vue spectral domain AS-OCT. pterygium thickness pre-operatively & keratectomy area along with autograft thickness after CLAT surgery was evaluated for a follow-up period of 3 months. Results: the pre-op pterygium & 3 months post-op keratectomy area thickness at apex for (group 1) were 854um & 573um, (group 2) were 855um & 578um, (group 3) were 859um & 574um and (group 4) were 868um & 575um. Similarly at limbus for (group 1) are 1.13um & 720um, for (group 2) are 1.14um & 725um, for (group 3) are 1.19um & 718um, for (group 4) are 1.24um & 714um. Reduction in graft thickness in 3 months follow period for (group 1) was 311um, (group 2) 304um, (group3) 303um & (group 4) 313um respectively. Conclusions: CLAT ascertains to be the ideal treatment modality for pterygium management in terms of decreasing the complications & recurrence rate. Also, AS-OCT is the optimal investigating modality in assessment of pterygium before & after CLAT surgery.

A COMPARATIVE STUDY TO EVALUATE THE CLINICAL OUTCOME OF CONJUNCTIVAL LIMBAL AUTOGRAFT AND AMNIOTIC MEMBRANE TRANSPLANT FOR THE TREATMENT OF PRIMARY PTERYGIUM

Aim: The aim of the study was to assess the safety and effectiveness of the conjunctival limbal autograft (CLAG) and amniotic membrane transplantation (AMT). Methods: After a full pre-operative assessment 100 patients with primary pterygium attending the ophthalmology outpatient department of a teaching hospital in Eastern India, fulfilling the inclusion and exclusion criteria were selected for our study. The patients were explained the procedure of the study and possible outcomes. They were divided into two groups. Group A: Where 10-0 nylon was to be used for CLAG after pterygium excision. Group B: Where 10-0 nylon was to be used for AMT after pterygium excision. Results: There was marked improvement in vision postoperatively more in the AMT group than CLAG. In the AMT group: 34% had a visual acuity of LogMAR 0.00, 30% had LogMAR 0.12, 12% had LogMAR 0.18, and 24% had LogMAR 0.30 after the surgery. In the CLAG group: 52% had a visual acuity of LogMAR, 20% had LogMAR 0.12, 22% had LogMAR 0.18, and 6% had LogMAR 0.30 after the surgery. Graft and suture-related complications were more in the CLAG group than in the amniotic membrane (AM) graft group. Conclusion: In the present study, The CLAG group was found to be associated with more discomfort, and more post-operative complications than AMT. AM may provide a basement membrane rich in various growth factors and matrix proteins, which promotes epithelial cell migration, adhesion, and differentiation. It is also believed to have anti-inflammatory and antifibrotic effects and exerts anti-scarring effects through the transforming growth factor-β pathway. AMT may be a superior treatment in primary pterygium due to lower recurrence rate, shorter surgical times, and better visual and cosmetic outcomes.

Comparison of mini-simple limbal epithelial transplantation and conjunctival–limbal autograft for the treatment of primary pterygium: a randomised controlled trial

PurposeThe purpose of this double-masked, parallel randomised controlled trial was to compare the recurrence rate and other outcomes between conjunctival–limbal autograft (CLAu) and mini-simple limbal epithelial transplantation (mini-SLET) after excision...

Ocular Surface Regeneration by Limbal Stem Cells Therapies: State of the Art, Challenges, and Perspectives.

Limbal stem cells (LSCs) are adult stem cells located at the limbus ensuring the continuous renewal of the corneal epithelium, critical to maintain an optimal visual function. Damages to the LSCs or their niche microenvironment lead to limbal stem cell deficiency (LSCD), a potentially blinding disease. Transplantation of LSCs as a treatment for severe to total LSCD has gained popularity since 1980s, owing to the clinical success of the first direct limbal autograft transplantation. Recent advances in the understanding of the LSCs' molecular identity and regulation have enabled preclinical and clinical advancements of promising LSCs therapies. However, lack of standardization of the diagnostic methods, staging of the disease severity, manufacturing process, and clinical outcome measures have hindered the advancement of the therapy. To move these therapies to the clinic, optimization and standardization of the diagnostic strategy, cell product manufacturing, and assessment of clinical efficacy with potency assays are key points to the development of customized therapies. Recent findings suggest that residual LSCs exist in eyes presenting with clinical signs of total LSCD, which opens new therapeutic strategies for eyes with partial LSCD. Prospective, randomized, multicentric controlled clinical trials are necessary to determine the efficacy of different LSCs therapies for different stages of LSCD using a set of standardized outcome measures.

A STUDY ON EFFECT OF PTERYGIUM EXCISSION ON PTERYGIUM INDUCED ASTIGMATISM

Purpose: Methods: To determine the effect of pterygium excision on pterygium induced astigmatism. A statistical comparison of the refractive astigmatism before and after effective pterygium surgery was done on 30 patients who underwent preoperative and postoperative refraction testing. pterygium surgery caused si Results: gnicant improvements in visual acuity, with the rule astigmatism. The corneal astigmatism tended to decrease s Conclusion: ignicantly following pterygium excision with conjunctival limbal autograft transplantation.

Comparison between Limbal Autograft Transplantation and Subconjunctival Bevacizumab Injection in Lowering Recurrence of Primary Pterygium

Comparison between Limbal Autograft Transplantation and Subconjunctival Bevacizumab Injection in Lowering Recurrence of Primary Pterygium

Limbal stem cell transplantation and keratoprosthesis

AbstractLimbal stem deficiency (LSCD) is a severe ocular disease which may lead to vision impairment or corneal blindness. Beside conservative options like topical and systemical medical therapy, chronic stage treatment options include conjunctival replacement procedures and limbal autografting. If limbal cell transplanation in form of either cultivated limbal epithelial transplantation (CLET), simple limbal epithelial transplantation (SLET) or conjunctival limbal autograft (CLAU) and corneal transplantation are not successful a Keratoprosthesis in form of a Boston Keratoprosthesis or a Osteo‐odonto‐ Keratoprosthesis might be the last chance for these patients. In the following presentation indication and surgical options in LSCD will be discussed.

Effects of amniotic membrane transplantation combined with limbal stem cell autograft transplantation on ocular burns

Effects of amniotic membrane transplantation combined with limbal stem cell autograft transplantation on ocular burns

Analysis on the efficacy of different exsection range in pterygium

Objective To analyse the efficacy of different exsection range in pterygium excision combined with conjunctival limbal autograft transplantation. Methods The clinical data of 86 eyes of 86 patients with ptergium, from Jan. 2016 to Jan. 2017 were analyzed retrospectively.Among them 2 cases were recurrent pterygium. All cases were divided into 2 groups randomly.Group A, 44 cases, treated with pterygium extended excision combined with Tenon’s capsule excision.Group B, 42 cases, received obvious hyperplasia pterygium excision only.The follow-up time was 1 year.Postoperative recurrence rates, efficacy and complications between both groups were compared and analyzed. Results The difference of length, width of pterygium invaded the cornea and the age of onset were not statistically significant between the two groups (P=0.247, 0.185, 0.125). In group A, the conjunctival of grafting bed occurred persistent congestion in 3 eyes after surgery. At the end of follow up, no recurrent or scar exposure occured.In group B, there were 10 cases with repeated conjunctival congestion in grafting bed. The conjunctival fibrovascular tissue proliferation and significant scar tissue exposure occured in 5 eyes(11.9%). Conclusion Pterygium extended excision combined with Tenon’s capsule excision is an efficient method for pterygium.It may reduce recurrence and improve postoperative conjunctival congestion. Key words: Surgery; Pterygium; Exsection range; Recurrence

Comparison on the efficacy between two kinds of surgery for pterygium in Taza Area, Morocco

Objective To compare the efficacy between simple excision of pterygium and excision of pterygium combined with corneal limbal stem cells autograft transplantation (LAT) for pterygium in Taza, Morocco. Methods The clinical data of 147 eyes of 133 patients with pterygium from Mar.2015 to Apr.2016 were retrospectively analysed. All patients were divided randomly into group A(control group)and group B(observation group). Group A, 60 eyes of 54 patients, received simple excision of pterygium; group B, 87 eyes of 79 patients underwent excision of pterygium combined with LAT. The recurrence rates were compared between two groups. Results The follow-up time was 3-12 months.The recurrent pterygium of group A at 3 months after surgery occurred in 5 eyes (8.3%) and 3 eyes (3.4%) in group B, the difference was not significant between two groups(χ2=0.834, P=0.361). Six months after surgery, the recurrent pterygium occurred in 11 eyes (18.3%) in group A and 8 eyes (9.2%) in group B, the difference was not significant between two groups(χ2=2.634, P=0.105). At 12 months after surgery, the recurrent pterygium occurred in 16 eyes (26.7%) in group A and 11 eyes (12.6%) in group B, the difference was statistically significant between two groups(χ2=4.567, P=0.031). Conclusion The highest recurrence rate of pterygium happens at 12 months after operation in Taza Area, Morocco. The surgery combined excision of pterygium with LAT is effective with lower recurrence rate. Key words: Pterygium; Limbal stem cells autograft transplantation(LAT); Recurrence rate

Efficacy of amniotic membrane transplantaion combined with limbal stem cell autograft transplantation for recurrent pterygium with symblepharon

Objective To evaluate the efficacy of amniotic membrane transplantation combined with limbal stem cell autograft transplantation for recurrent pterygium with symblepharon. Methods The data of 12 eyes of 12 cases with recurrent pterygium and symblepharon from Apr. 2013 to Aug. 2016 were collected and analyzed retrospectively. They underwent amniotic membrane transplantation combined with limbal stem cell autograft transplantation, and the application of mitomycin C during surgery. Results The follow-up period was 8-36 months, pterygium recurred in 1 case after surgery and the recurrent rate was 8.33%. No symblepharon or histolysis complication occurred. Conclusion Amniotic membrane transplantation combined with limbal stem cell autograft transplantation and application of mitomycin C intraoperatively for recurrent pterygium with symblepharon is efficient. Key words: Pterygium, recurrent; Symblepharon; Transplantaion, amniotic membrane; Transplantation, limbal stem cell autograft; Mitomycin C

Corneal Epithelial Stem Cells Repopulate the Donor Area within 1 Year from Limbus Removal for Limbal Autograft

To determine whether limbal epithelial stem cells (LESCs) repopulate the site harvested for limbal autograft transplantation (LAT), the expression of LESCs markers was evaluated in bioptic specimens obtained from the donor area 12 months or more after surgery. Interventional case series. Patients who underwent LAT for unilateral acquired limbal stem cell deficiency after chemical burn. Corneal limbal explants were obtained from 2 sites, the harvested area and the untouched control area, in the donor eyes of 6 patients who previously underwent LAT for unilateral acquired limbal stem cell deficiency after chemical burn. Limbal epithelial stem cells were isolated, and cellular, immunohistochemistry, and histologic parameters were assessed to compare differences between LESCs isolated from harvested or control sites. Presence of LESCs 1 year or more after LAT. Specific markers (p63, Ki67, K12), percentage of LESCs, cell doubling, and number of passages in culture did not differ significantly between harvested and control sites. However, the distinctive structure of the palisades of Vogt was found only in 2 of 6 harvested sites. Limbal epithelial stem cells repopulate the donor site as early as 1 year after limbus removal for LAT. Autologous transplantation of conjunctiva and limbus are safe procedures and can be performed in cases that cannot be treated by simple grafting of LESCs cultured exvivo.

Living-related limbal allograft transplantation for bilateral stem cell deficiency in a patient with bilateral chemical burn

INTRODUCTION. The purpose of this paper was to report the long-term outcome of a living-related limbal allograft transplantation followed by penetrating keratoplasty in a patient with severe bilateral stem cell deficiency. MATERIALS AND METHODS. A 50-year-old woman presented with extensive bilateral stem cell deficiency secondary to ocular acid burn on both eyes. Visual acuity was counting fingers at 30 cm on the right eye and counting fingers at 1 m Snellen line on the left. Limbal allograft transplantation on the right eye from a first-degree living-related relative was performed. The recipient was prepared by removing the abnormal corneal epithelium and vascularised pannus of the right eye under general anaesthesia. Two limbal allografts (mean length of 2–3 corresponding anatomic posi­tions on the recipient). Postoperatively, the host received systemic immunosuppression (steroids and cyclosporine). RESULTS. The cornea of the right eye achieved reepithelialisation within two weeks after surgery, followed by re­duction in vascularity in eight weeks time. After one year of regular follow up, the corneal surface remained stable whereas the stroma was opaque and the vision was low. Therefore, the patient underwent penetrating keratoplasty on the same eye. After the surgery the corneal graft was clear and the visual acuity on the right eye improved to 20/50 Snellen line. No graft rejection occurred after a five-year follow-up. CONCLUSION. Living-related limbal allograft transplantation is a good alternative option in cases of total bilateral stem cell deficiency whenever a conjunctival limbal autograft transplantation is not possible.

Roles of limbal microvascular net and limbal stroma in regulating maintenance of limbal epithelial stem cells.

Knowledge of the microenvironment (niche) of stem cells is helpful for stem-cell-based regenerative medicine. In the eye, limbal epithelial stem cells (corneal epithelial stem cells) provide the self-renewal capacity of the corneal epithelium and are essential for maintaining corneal transparency and vision. Limbal epithelial stem cell deficiency results in significant visual deterioration. Successful treatment of this type of blinding disease requires studies of the limbal epithelial stem cells and their microenvironment. We investigate the function of the limbal microvascular net and the limbal stroma in the maintenace of the limbal epithelial stem cell niche in vivo and examine the regulation of limbal epithelial stem cell survival, proliferation and differentiation in vivo. We assess the temporal and spatial changes in the expression patterns of the following markers during a six-month follow-up of various rabbit limbal autograft transplantation models: vascular endothelial cell marker CD31, corneal epithelium differentiation marker K3, limbal epithelial stem-cell-associated markers P63 and ABCG2 and proliferating cell nuclear marker Ki67. Our results suggest that limbal epithelial stem cells cannot maintain their stemness or proliferation without the support of the limbal microvascular net microenvironment. Thus, both the limbal microvascular net and the limbal stroma play important roles as components of the limbal epithelial stem cell niche maintaining limbal epithelial stem cell survival and proliferation and the avoidance of differentiation. The limbal stroma constitutes the structural basis of the limbal epithelial stem cell niche and the limbal microvascular net is a requirement for this niche. These new insights should aid the eventual construction of tissue-engineered cornea for corneal blind patients in the future.

Comparison on clinical efficacy of limbal autograft transplantation and amniotic membrane transplantation in treating pterygium

Objective To explore the clinical effects of limbal autograft transplantation (LAT) and amniotic membrane transplantation (AMT) in treating ptery gium.Methods 180 eyes of 159 cases with pterygium were randomly divided into two groups:LAT group (90 eyes in 81 cases) and AMT group (90 eyes in 78 cases).The recurrences of pterygium were observed and analyzed during the follow-up of 12 months.Results The corneal healing time of LAT group was (5.50 ± 1.27) days,while (8.70 ± 1.49) days in AMT group,it was statistically significant (P ＜ 0.01).There were 3 recurrences (3.33％) in LAT group and 16 recurrences (17.78％) in AMT group and it was statistically significant (P ＜ 0.01).Conclusion LAT could improve the corneal healing time and decrease the recurrence rate,which may be a valuable and effective way in clinic to treat pterygium. Key words: Pterygium; Limbal autograft transplantation; Amniotic membrane transplantation; Efficacy observation

Conjunctival limbal autograft transplantation in pterygium surgery by natural haemostasis

History of pterygium surgery dates back to 1000 BC.1,2 In earlier days “Bare Sclera” technique for pterygium removal was popular, as it was considered simple procedure. However, simple excision was associated with a high rate of recurrence that may be more aggressive than the initial lesion.3 Subsequently, many techniques aimed at preventing recurrence have been described like radiation treatment and the use of antimetabolite chemicals that prevent the growth of tissue.4 Currently the most widely used technique involves excision of the pterygium and covering of the defect with conjunctival autograft or amniotic membrane. Initially, sutures were used to cover the defect with conjunctival autograft. Recent report favour the use of fibrin glue above sutures with improved comfort, decreased surgical time, reduced complication of recurrence rates.5 Conventional suturing causes complications like foreign body reaction, infection, scarring in maximum no of patients.5 Their application is slow and needs skill. In the search of solution of these problems, concept of tissue adhesive was floated.6 Fibrin glue is a biological tissue adhesive which initiates the final stages of coagulation when a solution of human fibrinogen is activated by thrombin. However, plasma derived fibrin glue has the potential risk of prion disease transmission and anaphylaxis in susceptible individuals. In our case, we have achieved conjunctival limbal autograft adherence by natural haemostasis. Natural coagulation in human tissue begins almost instantly whenever there is an injury to the blood vessel endothelium. Fibrin clot which is formed through coagulation cascade allows to secure a conjunctival limbal autograft in place on the eye.7

English

INTRODUCTION: Amniotic membrane is the innermost layer of the fetal membranes. It has a stromal matrix, a collagen layer, and an overlying basement membrane with a single layer of epithelium. (1) Amniotic membrane has unique properties including anti-adhesive effects, bacterio-static properties, wound protection, pain reduction, and epithelialisation effects. Another characteristic of amniotic membrane is the lack of imunogenicity. (2) Amniotic membranes have been used as a dressing to promote healing of chronic ulcers of the leg and as a biological dressing for burned skin and skin wounds. (3, 4) It has also been used in surgical reconstruction of artificial vagina, for repairing omphaloceles, and to prevent tissue adhesion in surgeries of the abdomen, head, or pelvis. (5, 6) Amniotic membrane has been successfully used in ocular conditions like persistent epithelial defects (7), pterygium, (8) Symblepharon (9) and for ocular surface reconstruction.(10, 11) The purpose of this study was to evaluate the use of cryopreserved Human amniotic membrane graft( HAMT), with or without limbal autograft transplantation (LAT) in patients with previous and fresh chemical eye injuries respectively. Institutional ethical committee approval was obtained.

Limbal stem cells transplantion for the treatment of pterygium

Objective To investigate the clinical effects of reconstruction of limbal stem cells for pterygium through limbal stem cells transplantion.Methods 1032 cases( 1285 eyes) with ptergium were treated with limbal stem cells autograft transplantation in our hospital in the lated six years.The patients were treated with strict medicine and regular return visit after operation,and they were followed up from six months to 5 years.Results The 46 eyes of all the 1285 eyes recured after operation,account for 3.58％.Conclusion It is an ideal operative method for pterygium since the limbal stem cells autograft transplantation reconstructed the functional active limbal stem cells. Key words: Cells, stem, limbal; Reconstruction; Pterygium

Limbal autograft transplantation in a dog with alkali-induced ulceration

A case of a 3-month-old female mongrel dog with a history of apathy and previous contact with an alkaline (sodium hydroxide) is reported. The dog was reluctant to open the right eye. Ophthalmic examination revealed blepharospasm, photophobia, epiphora, discrete chemosis, conjunctival hyperemia, and diffuse corneal edema involving the limbus. The fluorescein test was positive and the result of the Schirmer tear test was 32mm min-1. On the basis of these findings the diagnosis was alkali-induced ulceration and limbal autograft transplantation was performed. Corneal vascularization was observed by the third postoperative day, with intensification in vessel number and caliber on subsequent days and small areas of corneal transparency. The present results show that limbal autograft transplantation is a feasible procedure for the therapeutic management of alkali-induced corneal ulcers.

Review of Surgical Strategies for Ocular Surface Disease

Abstract The concept of ocular surface diseases has evolved over 4 decades to involve specific medical and surgical approaches designed to remedy the diverse but specific disorders that beset the ocular surface. As such, the surgical strategies comprise the following: superficial keratectomy, conjunctival autograft transplantation, limbal autograft and allograft transplantation, ex vivo limbal expansion autografts, amnion membrane transplantation, and keratoprosthesis. The appropriate applications of these surgical approaches, as reviewed here, have enormously advanced our ability to reconstruct the anatomy and restore the vision of the diseased or damaged ocular surface.