Autologous Limbal Stem Cell Transplantation Research Articles

Understanding Ocular Surface Inflammation in Tears Before and After Autologous Cultivated Limbal Epithelial Stem Cell Transplantation.

We aimed to determine the expression of inflammatory cytokines in the tears of patients with unilateral total limbal stem cell deficiency (TLSCD) caused by chemical burns before and after autologous cultivated limbal epithelial stem cell transplantation (CLET). Tear samples were collected from both eyes of 23 patients with unilateral TLSCD and 11 healthy controls, at fixed timepoints before and after CLET. Dissolved molecules were extracted from Schirmer's strips using a standardised method and analysed on an array plate of ten inflammatory cytokines (V-Plex Proinflammatory Panel 1 Human Kit, MSD). IL1β expression was significantly elevated in the TLSCD eye compared with the unaffected eye at baseline (p < 0.0001) but decreased to normal 3months post-CLET (p = 0.22). IL6 and IL8 were unaffected at baseline but significantly elevated in the TLSCD eyes at 1month post-CLET (p = 0.001 and p < 0.0001, respectively). IL6 returned to normal at 3months and IL8 at 6months post-CLET. There was a significant renewed increase in IL1β, IL6 and IL8 expression at 12months post-CLET (p < 0.0001, p = 0.0001 and p = 0.0003, respectively). IFNγ, IL10 and IL12p70 expression were significantly reduced in both eyes of patients with unilateral TLSCD at all timepoints. IL1β is a specific marker of inflammation in TLSCD eyes that could be therapeutically targeted pre-CLET to improve stem cell engraftment. At 12months post-CLET the spike in levels of IL1β, IL6 and IL8 coincides with cessation of topical steroids, suggesting ongoing subclinical inflammation. We therefore recommend not discontinuing topical steroid treatment in cases where penetrating keratoplasty is indicated; however, further investigation is needed to ascertain this. European Union Drug Regulating Authorities Clinical Trials Database (EuDRACT 2011-000608-16); ISRCTN (International Standard Randomised Controlled Trial Number (isrctn51772481).

A Review of the Diagnosis and Treatment of Limbal Stem Cell Deficiency.

Limbal stem cell deficiency (LSCD) can cause significant corneal vascularization and scarring and often results in serious visual morbidity. An early and accurate diagnosis can help prevent the same with a timely and appropriate intervention. This review aims to provide an understanding of the different diagnostic tools and presents an algorithmic approach to the management based on a comprehensive clinical examination. Although the diagnosis of LSCD usually relies on the clinical findings, they can be subjective and non-specific. In such cases, using an investigative modality offers an objective method of confirming the diagnosis. Several diagnostic tools have been described in literature, each having its own advantages and limitations. Impression cytology and in vivo confocal microscopy (IVCM) aid in the diagnosis of LSCD by detecting the presence of goblet cells. With immunohistochemistry, impression cytology can help in confirming the corneal or conjunctival source of epithelium. Both IVCM and anterior segment optical coherence tomography can help supplement the diagnosis of LSCD by characterizing the corneal and limbal epithelial changes. Once the diagnosis is established, one of various surgical techniques can be adopted for the treatment of LSCD. These surgeries aim to provide a new source of corneal epithelial stem cells and help in restoring the stability of the ocular surface. The choice of procedure depends on several factors including the involvement of the ocular adnexa, presence of systemic co-morbidities, status of the fellow eye and the comfort level of the surgeon. In LSCD with wet ocular surfaces, autologous and allogeneic limbal stem cell transplantation is preferred in unilateral and bilateral cases, respectively. Another approach in bilateral LSCD with wet ocular surfaces is the use of an autologous stem cell source of a different epithelial lineage, like oral or nasal mucosa. In eyes with bilateral LSCD with significant adnexal issues, a keratoprosthesis is the only viable option. This review provides an overview on the diagnosis and treatment of LSCD, which will help the clinician choose the best option amongst all the therapeutic modalities currently available and gives a clinical perspective on customizing the treatment for each individual case.

Curative effect of pterygium resection and autologous limbal stem cell transplantation combined with amniotic membrane transplantation in the treatment of pterygium

Curative effect of pterygium resection and autologous limbal stem cell transplantation combined with amniotic membrane transplantation in the treatment of pterygium

Autologous limbal stem cell transplantation: a systematic review of clinical outcomes with different surgical techniques

PurposeTo conduct a systematic review on outcomes of three different techniques of autologous limbal stem cell transplantation (LSCT): conjunctival-limbal autografting (CLAu), cultivated limbal epithelial transplantation (CLET) and simple limbal epithelial...

Amniotic membrane transplantation with or without autologous cultivated limbal stem cell transplantation for the management of partial limbal stem cell deficiency.

PurposeTo compare the outcomes of amniotic membrane transplantation (AMT) vs cultivated limbal stem cell transplantation (LSCT) in eyes with partial limbal stem cell deficiency (LSCD) following chemical burns.MethodsEyes with unilateral partial LSCD (#180° involvement) were randomized in two groups to undergo either pannus resection combined with AMT or pannus resection combined with LSCT in a tertiary eye care hospital. Primary outcome measures were time to corneal epithelialization and absence of conjunctivalization of the cornea. Patients were followed up at 1 week, 1, 3, 6, and 12 months after the surgical procedure.ResultsThere was no difference between mean age (30.85±5.8 vs 28.64±6.4 years, P=0.40) and sex distribution of patients between the two groups at baseline. Mean time to corneal epithelialization was 10.45±5.8 days in the AMT group and 11±3.9 days in the LSCT group (P=0.43). At the end of 1 year, there was no significant difference between the degree of conjunctivalization of cornea, (P=0.06) corneal vascularization, (P=0.08), and clarity (P=0.07) in both groups.ConclusionOur study showed that AMT alone is a useful therapeutic modality in cases with partial LSCD due to ocular chemical injury. Stem cell transplantation may not be required in these cases.

Outcomes of Penetrating Keratoplasty Following Autologous Cultivated Limbal Epithelial Stem Cell Transplantation.

The purpose of this study is to investigate the outcomes of penetrating keratoplasty (PKP) following autologous cultivated limbal epithelial stem cell transplantation (CLET). A prospective, single center, interventional cohort study investigating patients with unilateral total limbal stem cell deficiency (LSCD) treated with CLET who underwent PKP. Patients with confirmed corneal re-epithelialization > 6 months post-CLET, and with best-corrected visual acuity (BCVA) <0.3 logMAR were offered PKP. CLET survival assessed by slit lamp, corneal impression cytology (CIC), and in vivo confocal microscopy. Confirmation of corneal re-epithelialization by histological and immunocytochemical (ICC) examination of trephined corneal buttons. Mean change in best-corrected visual acuity (logMAR) following PKP and PKP survival at 12 months were calculated. Twenty patients underwent PKP. Mean time of PKP was 19 months (range 11-41 months, SD 7.26) post-CLET. Median follow-up time post-PKP was 15 months (range 1-32, SD 10.2). CIC and ICC of all corneas confirmed corneal re-epithelialization before PKP. Mean pre-PKP BCVA was 1.46 (range 0.3-2.7, SD 0.94) improving to a mean post-PKP BCVA of 0.74 (range 0-2.7, SD 0.87); mean improvement in BCVA post-PKP of 36 letters (95% CI 15.0-57.1, p = .002). Kaplan-Meier mean graft survival was 90.9% (95% CI 50.8-98.7) at 12 months. We recommend a two-stage approach with CLET followed by PKP >12 months later. Patients experienced a significant improvement in BCVA following PKP. PKP did not have a detrimental effect on CLET survival. PKP survival post-CLET is better than that reported for high risk PKP. Stem Cells 2018;36:925-931.

Comparison of two different surgical methods for the treatment of pterygium

Objective To compare the clinical efficacy of transplantation of autologous corneal limbal stem cell and autologous conjunctiva transplantation in the treatment of pterygium. Methods The data of 84 eyes of 68 cases with primary pterygium from Jan. 2015 to Apr. 2016 were collected. The patients were randomly divided into two groups. Group A, 42 eyes, received pterygium excision combined with autologous limbal stem cell transplantation.Group B, 42 eyes, received pterygium excision combined with autologous conjunctiva transplantation.The follow-up time was 1 year.Corneal epithelial healing time and the recurrence of pterygium were compared between the two groups. Results The time of corneal epithelial healing was (2.87±0.64) days in group A and (4.83±0.76) days in group B, the difference was statistically significant between the two groups (t=3.480, P=0.009). Two eyes relapsed in group A, the recurrence rate was 4.8%; 8 eyes relapsed in group B, the recurrence rate was 11.9%.The differences between two groups were statistically significant(χ2=4.368, P=0.036). Conclusion Autologous corneal limbal stem cell transplantation can accelerates corneal wound recovery, reduces the recurrence of pterygium. Key words: Pterygium; Transplantation, autologous limbal stem cell; Transplantation, autologous conjunctiva

Ocular surface reconstruction in severe contact lens associated pathology

SummaryLimbal stem cells insufficiency (LSCI) can be primary (PLSCI) or secondary. (SLSCI). LSCI can be total or partial. Sings and symptoms of LSCI are: decreased visual acuity, photophobia, pain, and corneal epithelial defects leading to the loss of transparency. Conjunctivilzation of the cornea is a symptom sine qua non of total SLSCI. 5–15% cases of SLSCI are after contact lenses wearing. The LSCI in long term contact lens wearers is caused by oxygen level reduction, mechanical irritation and / or inflammatory etiology of corneal limbus. Treatment includes the use of topical corticosteroids, cyclosporin A application of preservative free artificial tears eye drops. Surgical treatment includes: the autologous or allograft limbal stem cell transplantation. Autologous cultured limbal stem cell transplantation is a new method with standardized number of transplanted limbal stem cells. All surgical options of treatment will be discussed.

Clinical observation on limbal stem cell transplantation and amniotic membrane transplantation for the treatment of pterygium

Objective To observe the clinical effect of amniotic membrane transplantation and autologous corneal limbal stem cell transplantation in the treatment of primary pterygium. Methods Seventy-five eyes of 68 cases of pterygium were randomly divided into two groups: the stem cell transplantation groups, 38 eyes of 35 cases, underwent pterygium excision combined with autologous limbal stem cell transplantation; amniotic membrane transplantation group, 37 eyes of 33 cases, underwent pterygium excision combined with amniotic membrane transplantation. The postoperative recurrence, corneal wound healing time and complications of two groups were observed. Results The recurrence rate of stem cell transplantation group was 2.6%, the recurrence rate of amniotic membrane transplantation group was 18.9%, and the recurrence rate of stem cell transplantation group was lower than that of amniotic membrane transplantation group. In the stem cell transplantation group, corneal wound healing time was average (3.49±0.50) days, the average time of corneal wound healing time was (5.28±1.37) days. The corneal wound healing time of the stem cell transplantation group was shorter than that of the amniotic membrane transplantation group, the difference was statistically significant (t=7.550, P=0.000). Conclusion The effect of autologous corneal limbal stem cell transplantation for primary pterygium, with shorter healing time, lower recurrence rate and fewer complications, is better than that of amniotic membrane transplantation. Key words: Pterygium; Transplantation; Stem cell; Amniotic membrane

Clinical observation of pterygium excision combined with autologous limbal stem cell transplantation in the treatment of 50 cases of primary pterygium

Objective To observe the curative effects of pterygium excision combined with autologous limbal stem cell transplantation in the treatment of primary pterygium. Methods 50 cases (72 eyes) of primary pterygium were selected in our hospital.According to the method of random number table, 50 canses were divided into the control group (37 eyes) underwent pterygium excision and the study group (35 eyes) received autologous limbal stem cell transplantation on the basis of the control group, with 25 cases in each, and the efficacy were compare between the two groups. Results The healing time of study group[(3.02±0.37)d] was significantly shorter than in the control group[(6.85±0.48)d](t=2.95, P=0.01) and the recurrence rate (20%) was significantly lower than in the control group (52%) (χ2=10.35, P=0.03), and the postoperative complications rate (8%) was significantly lower than in the control group (36%) (χ2=13.94, P=0.03). Conclusion Compared with pure pterygium excision, pterygium excision combined with autologous limbal stem cell transplantation in the treatment of primary pterygium has higher clinical efficacy, which can effectively shorten the repair time and reduce recurrence rate, with high safety, so it is worthy of further promotion and application in clinic. Key words: Pterygium; Stem cell transplantation; Keratoplasty, penetrating

Human induced pluripotent stem cell differentiation and direct transdifferentiation into corneal epithelial-like cells.

The corneal epithelium is maintained by a small pool of tissue stem cells located at the limbus. Through certain injuries or diseases this pool of stem cells may get depleted. This leads to visual impairment. Standard treatment options include autologous or allogeneic limbal stem cell (LSC) transplantation, however graft rejection and chronic inflammation lowers the success rate over long time. Induced pluripotent stem (iPS) cells have opened new possibilities for treating various diseases with patient specific cells, eliminating the risk of immune rejection. In recent years, several protocols have been developed, aimed at the differentiation of iPS cells into the corneal epithelial lineage by mimicking the environmental niche of limbal stem cells. However, the risk of teratoma formation associated with the use of iPS cells hinders most applications from lab into clinics. Here we show that the differentiation of iPS cells into corneal epithelial cells results in the expression of corneal epithelial markers showing a successful differentiation, but the process is long and the level of gene expression for the pluripotency markers does not vanish completely. Therefore we set out to determine a direct transdifferentiation approach to circumvent the intermediate state of pluripotency (iPS-stage). The resulting cells, obtained by direct transdifferentiation of fibroblasts into limbal cells, exhibited corneal epithelial cell morphology and expressed corneal epithelial markers. Hence we shows for the first time a direct transdifferentiation of human dermal fibroblasts into the corneal epithelial lineage that may serve as source for corneal epithelial cells for transplantation approaches.

翼状胬肉切除联合自体角膜缘干细胞移植术治疗翼状胬肉的临床疗效观察

目的：观察和分析翼状胬肉切除联合自体角膜缘干细胞移植术治疗翼状胬肉的临床效果。方法：对85例85眼原发性翼状胬肉患者进行翼状胬肉切除联合自体角膜缘干细胞移植术治疗，观察术后1年胬肉的复发情况。结果：85例85眼中仅有4例4眼术后1年复发，复发率4.71%。结论：翼状胬肉切除联合自体角膜缘干细胞移植术术后复发率低，具有临床推广价值。 Objective: To investigate the clinical effects of autologous limbal stem cell transplantation for treatment of pterygium. Method: We analyzed the pterygium recurrences on 85 cases (85 eyes) of primary pterygium treated by pterygium excision combined with autologous limbal stem cell transplantation after one year of operation. Results: One year after operation, 4 cases (4 eyes) were relapsed. The recurrence rate was 4.71%. Conclusion: Excision of pterygium combined with autologous limbal stem cell transplantation has low recurrence rate.

Limbal Stem Cell Deficiency: Current Treatment Options and Emerging Therapies

Severe ocular surface disease can result in limbal stem cell deficiency (LSCD), a condition leading to decreased visual acuity, photophobia, and ocular pain. To restore the ocular surface in advanced stem cell deficient corneas, an autologous or allogenic limbal stem cell transplantation is performed. In recent years, the risk of secondary LSCD due to removal of large limbal grafts has been significantly reduced by the optimization of cultivated limbal epithelial transplantation (CLET). Despite the great successes of CLET, there still is room for improvement as overall success rate is 70% and visual acuity often remains suboptimal after successful transplantation. Simple limbal epithelial transplantation reports higher success rates but has not been performed in as many patients yet. This review focuses on limbal epithelial stem cells and the pathophysiology of LSCD. State-of-the-art therapeutic management of LSCD is described, and new and evolving techniques in ocular surface regeneration are being discussed, in particular, advantages and disadvantages of alternative cell scaffolds and cell sources for cell based ocular surface reconstruction.

Two different surgical procedures for treatment of pterygium

Objective To observe the effect of autologous corneal limbal stem cell transplantation (LCAT) with or without MMC for pterygium. Methods One hundred and twenty eyes of 120 cases of pterygium were selected in this study. The cases were numbered by the hospital case number and were divided into two groups according to the random number table. Patients in the control group were given LCAT treatment, and patients in the observation group were treated with LCAT+ MMC. The corneal epithelial healing time, recurrence rate and the effect on neovascuarization was observed. And the treatment effects between the two groups were compared. Results The total effective rates of observation group was 95.00%, which is better than that in control group (60.00%); the recurrence rates in observation group was 5.00%, which is better than that in control group (40.00%) (χ2=21.075, P=0.000). The eye irritation disappearance time, corneal epithelial healing time, and hospitalization time in observation group were (3.71±2.63) d, (4.12±1.31) d, and (13.61±2.43) d. That were not different form control group statistically (P>0.05). Infection occurred in 2 cases and sclera thinning occurred only 1 case of sclera thinning in control group and only 1 case of sclera thinning in observation group (t=17.905, P=0.000). Conclusion LCAT+ MMC in the treatment of pterygium can reduce the possibility of recurrence and tissue proliferation. Key words: Pterygium; Transplantation, stem cell, limbus; Mitomycin C

Observation on the effect of transplantation of autologous limbal epithelial stem cell for the treatment of pterygium

Objective To observe the clinical effect and complications of autologous limbal epithelial stem cell transplantation in the treatment of pterygium. Methods Eighteen eyes of 18 cases with pterygium were treated with corneal limbal stem cell transplantation. The vitality of grafts and recurrence of pterygium were observed. Results The follow-up time was 1 year. The pterygium recurred in one eye and the recurrent rate was 5.6%. No serious complications happened. Conclusion Autologous limbal epithelial stem cell transplantation is a better method for the treatment of pterygium. Intraoperative careful operation can bring better cosmetic effect. Key words: Limbus, corneal; Cells, stem; Grafting; Pterygium

Stem Cell-Based Treatment Modalities for Limbal Stem Cell Deficiency

Limbal stem cell deficiency (LSCD) is a complex ocular condition with difficulty in corneal epithelialization, persistent ep ithelial defects, corneal neovascularization, and corneal conjunctivalization. The reason underlying this condition could be either primary or secondary. Chemical and thermal burns, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, trauma, aniridia, ectodermal dysplasia, and iatrogenic mechanism are in the etiologic scope of the disease. Management of LSCD remains a controversial issue of ophthalmology. There are several treatment alternatives regarding the mechanism of the disease. These options include surface reconstruction with amniotic membrane, autologous and allogeneic limbal stem cell (SC) transplantation, and keratoplasty. There has not been a consensus on the choice of the treatment procedure, although more recently, cultivated SC transplantation has been shown to be a promising treatment modality in the management of LSCD. This review aims to give the readers up-to-date information on LSCD.

Three-year corneal graft survival rate in high-risk cases treated with subconjunctival and topical bevacizumab.

To evaluate the effect of combined subconjunctival and topical bevacizumab treatment on corneal graft survival rate in high-risk eyes. Prospective, consecutive, interventional case series. Fifty eyes of 50 high-risk patients scheduled for penetrating keratoplasty (PK) were included in the study; two Stevens-Johnson syndromes (SJS), five corneal combustions due to chemical burn, seven post-traumatic vascularised leucomas, 11 post-infectious vascularised leucomas, 19 rejected grafts and six corneal ulcers. Additional surgeries such as autologous limbal stem cell and/or amniotic membrane transplantation were performed together with PK in ten cases. All eyes received subconjunctival injection of 0.5ml bevacizumab (25mg/ml) after PK. Eyes with more than two quadrants of neovascularisation (NV) received bevacizumab drops (25mg/ml) postoperatively for up to 12weeks. Donor grafts were followed up for best-corrected visual acuity, graft clarity, change in NV, endothelial cell density loss (ECD), and adverse events. Mean follow-up was 36.5months (range 32-61). Best-corrected visual acuity increase was statistically significant in 82% (41/50) of eyes 3years after PK (paired t-test, p = 0.02). Thirty-five (70%) high-risk grafts remained clear throughout the 3-year follow-up period. Decrease of corneal NV was observed in 84% (42/50) of eyes treated with bevacizumab. ECD changed from preoperative 2,864 ± 301 down to 1,905 ± 187 cells/mm(2) at 3 postoperative years. A non-healing epithelial defect was recorded in one patient with SJS after 12weeks of topical bevacizumab. Combined subconjunctival and topical bevacizumab treatment may improve corneal graft survival rate in the majority of high-risk cases.

角膜缘干细胞移植治疗翼状胬肉的围术期护理

60 pterygium patients (64 eyes) were selected from our hospital, and they were all treated by pterygium excision with autologous limbal stem cell transplantation therapy, and they had scientific and reasonable perioperative nursing measures. 62 eyes recovered, 2 eyes recurred, and no postoperative infection and complications, achieve good results.

Phototherapeutic keratectomy for treatment of recurrent pterygium

Objective To evaluate the treatment outcomes of excimer laser phototherapeutic keratectomy (PTK) for recurrent pterygium.Methods 106 eyes of 106 patients diagnosed with recurrent pterygium that underwent PTK or autologous limbal stem cell transplantation were retrospectively evaluated.PTK treatment group (53 eyes):Pterygia were treated by separating and excising conjunctiva and pathological tissues.The residual pathological tissues underwent PTK with the Technolas 217z excimer laser.Control group (53 eyes):autologous limbal stem cell transplantation was performed.Data were analyzed for preoperative and postoperative reepitheliation,recurrence rate,and corneal astigmatism.Results The mean reepitheliation time of PTK group was (3.96 ± 0.78) days,and it was significantly shorter than that of control group (4.67 ± 1.01) days (t =-4.071,P ＜ 0.01).The mean postoperative corneal astigmatism in PTK group declined about (0.72 ± 0.80) D comparing to the preoperative one,and the improvement was signifi-cantly more than that of the control group (0.42 ± 0.43 D) (t =-1.342,P =0.02).The mean follow-up time was (18.05 ± 5.32) months.3 cases recurred in PTK group,the recurrence rate was 5.66％ ; 4 cases recurred in control group,the recurrence rate was 7.55％.There was no significant difference in recurrent rate between the two groups (x2 =0.368,P =0.70).Conclusion PTK can be a safe and effective therapeutic alternative for recurrent pterygium.It can avoid excessive operative trauma,hasten reepitheliation,and reduce corneal astigmastism.It can effectively decrease the recurrence rate of pterygium as autologous limbal stem cell transplantation. Key words: Keratectomy, phototherapeutic ; Pterygium; Stem cell, limbal

Aktuelle und zukünftige Therapieoptionen bei Erkrankungen der Limbusstammzellen

Therapy for limbal stem cell insufficiency (LSCI) is one of the most challenging tasks in ocular surface surgery. Partial and unilateral LSCI can be treated by fractionated abrasion or autologous limbal stem cell transplantation from the fellow eye. In cases of advanced bilateral and partial LSCI, transplantation of ex vivo expanded sheets of limbal stem cells on amniotic membrane or fibrin may be performed. All patients with complete bilateral LSCI must rely on allogenic limbal stem cell transplantation comprising higher immunological risks. Progress using this technique has been achieved by the application of mitomycin C and amniotic membrane. Alternatively, transplantation of ex vivo expanded oral mucosal sheets may be used in bilateral LSCI, but only few long-term data are available on this technique as yet. While experimental attempts to use transdifferentiated bone marrow stem cells as a substitute for corneal epithelial cells have been without success, transdifferentiation of hair follicle stem cells to corneal epithelial cells may be more promising due to the identical lineage. But these experiments have not gone beyond the in vitro stage yet.