Systemic Immunosuppression in Ocular Surface Stem Cell Transplantation: Results of a 10-Year Experience

Decellularized Descemet Membrane Anterior Keratoplasty With Allogeneic Simple Limbal Epithelial Transplantation for Partial Limbal Stem Cell Deficiency Following Partial Keratolimbal Allograft Failure

PURPOSE

The purpose of this study was to describe the use of Descemet membrane anterior keratoplasty (DMAK) with modified allogeneic simple limbal epithelial transplantation to treat a case of partial limbal stem cell deficiency (LSCD) following keratolimbal allograft failure.

METHODS

Case report.

RESULTS

A 21-year-old woman with autoimmune polyglandular syndrome-related LSCD presented with pain and decreased vision. There was partial failure and recurrence of LSCD after a severe/acute keratolimbal allograft rejection that led to persistent epithelial defects refractory to conservative therapy. This was treated with a superficial keratectomy and placement of a DMAK. A modified allogeneic simple limbal epithelial transplantation was performed with an overlying amniotic membrane and temporary tarsorrhaphy. There was epithelialization of the corneal surface by 3 to 4 weeks with an improved ocular surface. Despite partial recurrence of late staining, the cornea has remained epithelized, vision has improved, and the patient has remained pain-free more than 1.5 years following the procedure.

CONCLUSIONS

DMAK may be a long-term substrate to help improve and maintain epithelization of the cornea up to 1.5 years. DMAK may be a viable alternative to using amniotic membrane as a scaffold in allogeneic simple limbal epithelial transplantation for treatment of partial LSCD. While late epithelial staining recurred in our patient, DMAK appears to prevent recurrent epithelial defects and reduce ocular surface pain, conveying an improvement in quality of life in patients at high risk of rejection/failure.

Topical Tacrolimus Compared With Oral Tacrolimus for Postoperative Immunosuppression in Primary Keratolimbal Allograft

PURPOSE

The aim of this study was to compare outcomes between topical tacrolimus and oral tacrolimus as the primary calcineurin inhibitor for postoperative immunosuppression after primary keratolimbal allograft (KLAL) transplantation for limbal stem cell deficiency (LSCD).

METHODS

We performed a retrospective, comparative cohort study at a single tertiary referral center (University of MN) of all patients who underwent primary KLAL between 2014 and 2021. Eyes were grouped into those which received topical tacrolimus as the only calcineurin inhibitor (topical group) and eyes in which patients received oral tacrolimus with or without topical tacrolimus (oral group). Clinical and donor tissue data were obtained and compared between the 2 groups.

RESULTS

In total, 27 eyes of 22 patients (median age 42 years, range 20-79 years) were included, of which 18 eyes were in the oral group and 9 eyes were in the topical group. The mean follow-up time was 33.2 ± 22.6 months. The most frequent etiology of LSCD was alkaline burn (33.3%). At 36 months, graft failure occurred in 6 eyes in the oral group (33.3%) and 2 eyes in the topical group (22.1%) ( P = 0.57). The failure rate in the oral group was 9.1 per 1000 person-months versus 8.4 per 1000 person-months in the topical group ( P = 0.96). The median improvement in BCVA was logMAR -0.975 and logMAR -0.45 for the oral and topical group, respectively ( P = 0.50).

CONCLUSIONS

With careful patient selection, topical tacrolimus may be a viable alternative to oral tacrolimus in KLAL.

Real-World Experience in the Use of Immunosuppression for the Management of Inflammatory Eye Disease

PURPOSE

Patients with sight-threatening inflammatory eye disease (IED) are maintained on systemic immunosuppression whilst in long-term clinical remission. There are no clear guidelines on the duration of remission before implementing treatment withdrawal. We present a real-world analysis on the use of immunosuppression in IED in long-term remission and consider strategies for withdrawal.

METHODS

Adult IED patients on systemic immunosuppression were categorised into four disease groups: Corneal Transplant Survival Strategies (CTSS), Ocular Surface Disease (OSD), Non-infectious Uveitis (NIU) and Scleritis. Patients with Behçet's disease were excluded. Data on systemic immunosuppressants and biologics used; duration of treatment; reasons for drug discontinuation; disease activity/remission status; duration of clinical remission with an emphasis on patients who had been in remission for a minimum of 24 months were captured.

RESULTS

Out of a total of 303 IED patients, 128 were on systemic immunosuppression with a clinical remission of their ocular disease for ≥24 months. The median duration of remission was 4-5 years with the longest duration of remission 22 years, and some patients on immunosuppression for up to 23 years. Sixty patients stopped at least one immunosuppressive agent without prior discussion with a health-care practitioner.

CONCLUSION

Progressive conditions, such as cicatrising conjunctivitis may require lifelong immunosuppression, but patients with NIU and Scleritis and those on CTSS, immunosuppression withdrawal should be considered if they remain in remission for 2 years. Any patient stopping a medication should be contacted immediately for counselling. These data will better inform patients, encourage adherence and aide formal guideline development.

A Review of Contact Lens-Induced Limbal Stem Cell Deficiency

Limbal stem cell deficiency (LSCD) is a pathologic condition caused by the dysfunction and destruction of stem cells, stem cell precursors and limbal cell niche in the corneal epithelium, leading to severe conjunctivalization of the cornea. Etiologies for LSCD span from congenital (aniridia), traumatic (chemical or thermal injuries), autoimmune (Stevens-Johnson syndrome) and iatrogenic disease to contact lens (CL) wear. Of these, CL wear is the least understood and is often a subclinical cause of LSCD. Even with recent advances in LSCD research, limitations persist in establishing the pathogenesis and treatment guidelines for CL-induced LSCD. A literature search was conducted to include original articles containing patients with CL-induced LSCD. This review will critically discuss the complex pathophysiology behind CL-induced LSCD, the underlying risk factors and epidemiology of the disease as well as methods to obtain a diagnosis. Various treatment options will be reviewed based on proposed treatment strategies.

Allogeneic Ocular Surface Stem Cell Transplantation Outcomes With Decreased or No Systemic Immunosuppression in the Elderly

PURPOSE

The aim of this study was to report outcomes after allogeneic ocular surface stem cell transplantation (OSST) for limbal stem cell deficiency in the setting of decreased or no systemic immunosuppression (SI) in the elderly.

METHODS

A retrospective chart review was performed of all eyes that underwent OSST for limbal stem cell deficiency between 2005 and 2020 at CVP Physicians. Inclusion criteria included patients who were (1) at least 70 years at the time of (2) allogeneic OSST. Postoperative SI regimens were assessed. Outcome measures included improvement in visual acuity, ocular surface stability, and adverse effects.

RESULTS

There were 14 eyes of 14 patients that met the inclusion criteria with mean follow-up of 3.0 (range 0.4-7.0) years. SI was run at a lower level for 6 patients, and 8 patients did not receive any SI. Nine eyes underwent keratolimbal allograft, 1 had a living-related conjunctival limbal allograft, and 4 had combined OSST. Most eyes (85.7%) attained improvement in visual acuity during their follow-up. At the last follow-up, 57.1% maintained a stable ocular surface. Six eyes developed acute rejection or late failure. Minimal adverse events were noted.

CONCLUSIONS

Elderly patients administered less or no SI exhibit overall favorable outcomes after allogeneic OSST. Although not significantly different, surface stability and duration of improved vision was greater with low SI. No SI may be an option that still achieves improved vision in a high proportion for at least part of their follow-up. Decreasing SI after OSST in this population can improve quality of life while minimizing adverse effects.

Long-Term Comprehensive Management of Bilateral Limbal Stem Cell Deficiency Secondary to Severe Chemical Burn: 10 Years of Follow-Up

PURPOSE

To describe the long-term management of bilateral limbal stem cell deficiency secondary to a severe chemical burn.

METHODS

Descriptive case report.

IMPORTANCE

This case highlights the importance of early intervention in ocular chemical burns for the preservation of tissue integrity and avoidance of perforation. We also review the use of proper ocular surface reconstructive techniques to restore the function of the limbal area, as well as the immunomodulatory strategies and follow-up needed for these interventions.

Future directions in managing aniridia-associated keratopathy

Congenital aniridia is a panocular disorder that is typically characterized by iris hypoplasia and aniridia-associated keratopathy (AAK). AAK results in the progressive loss of corneal transparency and thereby loss of vision. Currently, there is no approved therapy to delay or prevent its progression, and clinical management is challenging because of phenotypic variability and high risk of complications after interventions; however, new insights into the molecular pathogenesis of AAK may help improve its management. Here, we review the current understanding about the pathogenesis and management of AAK. We highlight the biological mechanisms involved in AAK development with the aim to develop future treatment options, including surgical, pharmacological, cell therapies, and gene therapies.

Why Are Corneal Specialists Resistant to Treating Patients Who Have Severe Ocular Surface Disease With Limbal Stem Cell Deficiency?

PURPOSE

To highlight the paucity of surgeons performing ocular surface stem cell transplantation with systemic immunosuppression (OSSTx with SI) for limbal stem cell deficiency (LSCD) patients, suboptimal treatments for LSCD, and obstacles to adoption.

METHODS

A review of the Eye Bank Association of America annual reports and the authors' case volume for OSSTx with SI was performed. Examination of the published literature on corneal surgeries, especially for LSCD, was completed. These findings were combined with our clinical observations to develop this editorial.

RESULTS

Despite techniques and protocols for OSSTx with SI published more than 30 years ago for the treatment of severe bilateral LSCD, only a small number of corneal specialists have adopted these techniques. There is a paucity of attention to this population of patients, with minimal publications to advance this area of our field. We are too often referred patients with LSCD and severe ocular surface disease that have had suboptimal treatments such as penetrating keratoplasties or primary keratoprostheses. Hesitancy for adopting OSSTx with SI is likely due to a lack of exposure to these procedures during training and fear of systemic immunosuppression. Corneal surgeons are likely unaware of the safety of systemic immunosuppression with appropriate monitoring especially when comanaging these patients with an organ transplant specialist.

CONCLUSION

There is a large unmet need for the treatment of corneal blindness secondary to conjunctival and LSCD. For the vast majority of patients, OSSTx should be the first surgical choice to treat these eyes. We hope major ophthalmology centers will meet this need by building programs, and groups of corneal surgeons should collaborate to create regional centers to make this treatment more accessible to help this population.

Evaluation of the factors that influence surgical outcome in conjunctival-limbal allograft transplantation

OBJECTIVE

To evaluate the surgical results and the variables affecting the outcomes in conjunctival-limbal allograft transplantation (CLAL).

METHODS

Patients who underwent CLAL for limbal stem cell deficiency (LSCD) between 2007 and 2019 were included in the study. LSCD staging was performed according to the staging system developed by the 'Limbal Stem Cell Working Group'. Stage 1C and higher stage LSCD patients were included in the study. 'Successful surgical outcome' was defined as improvement in LSCD stage at 1 year postoperatively.

RESULTS

A total of 19 eyes of 19 LSCD patients were included. The mean age of the patients was 40.21 ± 14.65 (6-65) years, and the male/female ratio was 12/7. CLAL was performed in 9 (47.3%) patients with Stage 2B, 9 (47.3%) patients with Stage 3 and 1 (5.4%) with Stage 1C. LSCD aetiology; chemical injury (12), vernal keratoconjunctivitis (2), aniridia (1), corneal degeneration (1), and unknown (3). Surgery was successful in 52.6% of cases. Surgical success was associated with lower LSCD stage (p = 0.04). Lower grades of chemical injury at presentation and a longer time interval between injury and CLAL were associated with higher surgical success (p = 0.001; p = 0.001). The mean postoperative follow-up time was 50.77 ± 29.46 (6-98) months.

CONCLUSIONS

Despite graft rejection and long-term use of immunosuppressants, CLAL is still one of the most preferred techniques in the treatment of bilateral LSCD. Preoperative LSCD stage and degree of chemical burn are important factors affecting the surgical outcome. Also, CLAL surgery should not be rushed and should be performed when inflammation has subsided.

Refractory Keratolimbal Allograft Rejection in Autoimmune Polyglandular Syndrome-Associated Keratopathy Treated With Intravenous Immunoglobulin

PURPOSE

The aim of this study was to describe the use of intravenous immunoglobulin (IVIG) in the management of a 20-year-old woman with autoimmune polyglandular syndrome-associated keratopathy who developed acute transplant rejection after keratolimbal allograft (KLAL) surgery.

CASE

Nine weeks after KLAL surgery, a 20-year-old woman with autoimmune polyglandular syndrome-related limbal stem cell deficiency presented with graft injection, hemorrhage, and an epithelial rejection line. This was concerning for acute rejection in the setting of triple-agent systemic immunosuppression (albeit nonadherence at times). There was initial reversal of the rejection process with a sub-Tenon's injection of triamcinolone, frequent topical corticosteroids, increase in oral prednisone, and optimization of systemic immunosuppression medications; however, recurrence of the epithelial rejection line and symptoms were noted whenever the prednisone dose was tapered. This was accompanied by ocular surface decompensation (late staining, neovascularization, and persistent epithelial defects). She was found to have weakly positive HLA Class 1 antibodies. The patient was treated with a pulsed corticosteroid infusion and 2 monthly IVIG infusions. This led to resolution of the acute rejection. However, there was a subsequent rejection episode 4 months later after tapering the prednisone. Monthly IVIG for 6 more months led to final resolution with successful prednisone tapering and no further rejection.

CONCLUSIONS

Treatment with prolonged IVIG showed better improvement in a case of acute rejection refractory to traditional treatments, especially in the setting of HLA antibodies. The case demonstrates that close follow-up with a corneal specialist and collaboration with a transplant specialist is important to monitor for postoperative KLAL rejection.

En Bloc Keratolimbal Allograft and Central Penetrating Keratoplasty: A Novel Surgical Technique in Severe Limbal Stem Cell Deficiency

PURPOSE

The purpose of this study was to present a novel surgical technique combining 360-degree keratolimbal allograft (KLAL) and simultaneous central keratoplasty termed en bloc KLAL with the central penetrating keratoplasty (PKP) performed in those cases with total limbal stem cell deficiency (LSCD) and corneal scars.

METHODS

Nine eyes of 9 patients underwent en bloc KLAL and central PKP between 2014 and 2016. All patients had bilateral total LSCD with total corneal opacity due to different etiologies. The exclusion criteria were previous limbal stem cell transplantation and the presence of active and uncontrolled ocular surface inflammation. The same donor globe was used for harvesting 360-degree KLAL and central PKP. The 1-piece integrity of the KLAL and PKP graft was preserved during the described technique. All patients received modified immunosuppressive regimens compatible with the Cincinnati solid organ transplantation protocol.

RESULTS

The average age of patients was 58.6 ± 18.6 years. The diagnosis was mustard gas keratopathy in 6, herpes simplex keratitis in 1, and severe acid chemical burn in 2 patients. Seven patients were male. An integrated ocular surface without epitheliopathy and a clear cornea was achieved in 8 patients (88.8%) with an average of 6.5 years in follow-up. The average best-corrected visual acuity was 1.89 ± 0.18 (20/1600) preoperatively which improved to 1.02 ± 0.64 (20/200) logMAR in the postoperative period. Endothelial immune rejection episodes were observed in 3 patients. KLAL rejection was not observed in any patient. One patient required repeat PKP due to corneal graft failure.

CONCLUSIONS

En bloc 360-degree KLAL and central PKP could simultaneously be performed in patients with total LSCD and corneal opacification.

Genetic analysis of allogenic donor cells after successful allo-limbal epithelial transplantation in simple and cultivated limbal epithelial transplantation procedures

This non-comparative cohort study investigated long-term donor cell survival after allogenic simple/cultivated limbal epithelial transplantations (allo-SLET/allo-CLET, respectively) by genetic analysis. Transplanted corneal epithelial cells, which underwent impression cytology and/or corneal-button biopsy, were examined for personal identities of autosomal short-tandem repeats; the percentages of donor cells were calculated based on matching recipient or donor buccal-DNA references. Twelve patients were included; 4 underwent allo-CLET, 8 underwent allo-SLET. Eight patients (67%) had total limbal stem cell deficiency (LSCD). Genetic analysis was performed postoperatively (mean, 55.3 months). Donor cells were detected in 4 of 12 patients (25%), all of whom underwent allo-SLET; 1 patient had a donor genotype and 3 patients had a mixed donor/recipient genotype. The longest time of donor cell detection was 30 months. Seven patients (58%) used systemic immunosuppressives at the time of genetic analysis (mean use, 22.5 months). Allogenic donor cells survived in both procedures for the long term postoperatively, which encourages the long-term use of systemic immunosuppressives. Donor cells may not be the only factor in graft survival, in that most successful cases had a recipient profile. Their presence for a specific time may promote niches for the patients' own cells to repopulate, especially for partial LSCD.

Corneal Reconstruction with EGFP-Labelled Limbal Mesenchymal Stem Cells in a Rabbit Model of Limbal Stem Cell Deficiency

Ocular surface reconstruction is essential for treating corneal epithelial defects and vision recovery. Stem cell-based therapy demonstrates promising results but requires further research to elucidate stem cell survival, growth, and differentiation after transplantation in vivo. This study examined the corneal reconstruction promoted by EGFP-labeled limbal mesenchymal stem cells (L-MSCs-EGFP) and their fate after transplantation. EGFP labeling allowed us to evaluate the migration and survival rates of the transferred cells. L-MSCs-EGFP seeded onto decellularized human amniotic membrane (dHAM) were transplanted into rabbits with a modeled limbal stem cell deficiency. The localization and viability of the transplanted cells in animal tissue were analyzed using histology, immunohistochemistry, and confocal microscopy up to 3 months after transplantation. EGFP-labeled cells remained viable for the first 14 days after transplantation. By the 90th day, epithelialization of the rabbit corneas reached 90%, but the presence of viable labeled cells was not observed within the newly formed epithelium. Although labeled cells demonstrated low survivability in host tissue, the squamous corneal-like epithelium was partially restored by the 30th day after transplantation of the tissue-engineered graft. Overall, this study paves the way for further optimization of transplantation conditions and studying the mechanisms of corneal tissue restoration.

Corneal transplantation in aniridia-related keratopathy with a two-year follow-up period, an uncommon disease with precarious course

PURPOSE

The purpose of this study is to study the frequency, surgical transplantation technique and outcome in patients with aniridia-related keratopathy (ARK) with two-year follow-up period.

METHODS

A retrospective registry-study including all ARK cases performed in Sweden and Denmark between 2001 and 2016 and registered in the Swedish Cornea Transplant Registry.

RESULTS

A total of 36 eyes of 26 patients were subjected to corneal transplantation due to ARK during 2001 to 2016. Penetrating keratoplasty (PK) was the procedure of choice in 58.3% (n = 21) of the eyes, followed by a combination of PK and limbal stem cell transplantation in 13.9% (n = 5) and keratolimbal allograft in 13.9% (n = 5). Boston keratoprosthesis was used in 8.3% (n = 3), and anterior lamellar keratoplasty in 5.6% (n = 2). Thirteen of the procedures (36.1%) were retransplantations. Two years after surgery 26 cases were available to follow-up of which 16 of the grafts were functioning (61.5%). The median visual acuity showed a trend of improvement from hand motion to counting fingers.

CONCLUSIONS

A majority of the ARK cases (61.5%) had a graft providing useful vision for the patient 2 years after corneal transplantation, but the visual gain was modest at best. Longer follow-up time is required to evaluate functional graft outcomes. Despite the introduction of limbal stem cell transplantation as a suitable treatment, PK was the most common surgical method in the present study.

Diagnostic Algorithm for Surgical Management of Limbal Stem Cell Deficiency

BACKGROUND

Limbal stem cell deficiency (LCSD) presents several challenges. Currently, there is no clearly defined systematic approach to LSCD diagnosis that may guide surgical tactics.

METHODS

The medical records of 34 patients with LSCD were analyzed. Diagnostic modalities included standard (visometry, tonometry, visual field testing, slit-lamp biomicroscopy with corneal fluorescein staining, Schirmer test 1, ultrasonography) and advanced ophthalmic examination methods such as anterior segment optical coherence tomography, in vivo confocal microscopy, impression cytology, and enzyme-linked immunoassay.

RESULTS

Standard ophthalmological examination was sufficient to establish the diagnosis of LSCD in 20 (58.8%) cases, whereas advanced evaluation was needed in 14 (41.2%) cases. Depending on the results, patients with unilateral LSCD were scheduled to undergo glueless simple limbal epithelial transplantation (G-SLET) or simultaneous G-SLET and lamellar keratoplasty. Patients with bilateral LSCD with normal or increased corneal thickness were enrolled in the paralimbal oral mucosa epithelium transplantation (pLOMET) clinical trial.

CONCLUSIONS

Based on the diagnostic and surgical data analyzed, the key points in LSCD diagnosis were identified, helping to guide the surgeon in selecting the appropriate surgical procedure. Finally, we proposed a novel step-by-step diagnostic algorithm and original surgical guidelines for the treatment of patients with LSCD.

Outcomes of keratolimbal allograft from ABO compatible donors for severe bilateral limbal stem cell deficiency

PURPOSE

To report outcomes of keratolimbal allograft (KLAL) compatible for both human leukocyte (HLA) and/or blood type using oral prednisone, mycophenolate, and tacrolimus, with basiliximab if panel reactive antibodies (PRA) are present. Intravenous immunoglobulin (IVIG) was used post-operatively if donor-specific anti-HLA antibodies (DSA) were present.

METHODS

Retrospective interventional series of consecutive patients with KLAL for limbal stem cell deficiency (LSCD) from HLA and/or blood type compatible deceased donors with a minimum follow-up time of 12 months. Main outcome measures were ocular surface stability, visual acuity and systemic immunosuppression (SI) adverse events.

RESULTS

Eight eyes of eight patients with mean age of 48.6 ± 10.1 years (range 34-65 years) were included. Mean follow-up time was 37.3 ± 22.7 months (range 12-71 months) following KLAL; four (50%) had combined LR-CLAL surgery. The etiologies of LSCD were Stevens-Johnson Syndrome (n = 4/8), aniridia (n = 2/8), chemical injury (n = 1/8) and atopic eye disease (n = 1/8). All patients had PRA present and received basiliximab infusions. 5/8 patients received IVIG based on DSA identified pre-operatively. At last follow-up, 7 eyes (87.5%) had a stable ocular surface; 1 eye (12.5%) developed failure and had keratoprosthesis implantation. There was a significant improvement in visual acuity from 1.65 ± 0.48 to 0.68 ± 0.34 logMAR (p = 0.01). SI was tolerated well with minimal adverse events.

CONCLUSIONS

Preliminary outcomes of KLAL with ABO compatible tissue using the Cincinnati protocol, preoperative basiliximab (when PRA present) and post-operative IVIG (when DSA present) are encouraging. This protocol may allow for utilization of deceased donor tissue with results approximating those of living donor tissue transplanted for severe bilateral LSCD.

Use of Systemic Mycophenolate Mofetil Therapy in Ocular Surface Inflammatory Pathologies at the Initiative and Responsibility of the Ophthalmologist

PURPOSE

The purpose of the study was to evaluate the efficacy and safety of systemic mycophenolate mofetil (MMF) treatment in ocular surface inflammatory diseases.

METHODS

For this retrospective study, patients who were treated with systemic MMF for ocular surface inflammatory diseases between March 2020 and March 2022 were evaluated. Apart from demographic data, examination notes including MMF treatment indication and systemic side effect interrogation and routine laboratory examinations during drug treatment were extracted from the patient records. Detailed staging scores were performed according to the diagnosis including Foster and Mondino for ocular mucous membrane pemphigoid (MMP) and limbal stem cell deficiency scoring for limbal transplantation. For thorough evaluation, anterior segment pictures were used.

RESULTS

Fourteen patients were enrolled to the study, with a mean age of 58 ± 12. MMP (6, 42.8%) and limbal allograft transplantation (6, 42.8%) constituted the main indications for the MMF treatment, followed by keratitis-ichthyosis-deafness (KID) syndrome (1, 7.2%) and Mooren's ulcer (1, 7.2%). Five of six patients with MMP regressed according to both staging systems. Only one remained stable which was evaluated as Stage 3. Furthermore, while all limbal transplant groups (6) stabilized and showed regression according to the individualized limbal stem cell deficiency staging system with no rejection during follow-up. Furthermore, patients with Mooren's ulcer and KID syndrome showed control of the inflammation and stabilization after MMF treatment. No significant systemic side effects apart from constipation and nausea (3) were observed in patients whose routine laboratory tests were stable throughout the follow-up.

CONCLUSION

MMF has the potential to be a valuable and safe systemic agent of first choice in the control of ocular surface inflammatory disorders, especially when topical treatment is not effective. With such studies, it is predicted that MMF may reach wider usage areas with the increase in its effectiveness and safety in its use for ocular surface inflammatory pathologies.

Case Report: Allogenic Simple Limbal Epithelial Transplantation From a Human Leukocyte Antigen-Matched Living Related Donor to Treat Bilateral Corneal Chemical Burns Post Laser-Assisted in situ Keratomileusis

A 35-year-old woman who had undergone laser-assisted in situ keratomileusis in both eyes experienced bilateral total limbal stem cell deficiency (LSCD) due to chemical burns. Due to bilateral severe LSCD, allogenic simple limbal epithelial transplantation (SLET) from a human leukocyte antigen (HLA)-matched living related donor was the first choice of treatment for her left eye. We report the first case of HLA or ABO matching living related allogenic SLET for permanent restoration of the cornea for bilateral LSCD treatment. Our ABO-HLA-matched living related allogenic SLET alleviation of the systemic immunosuppressant to topical corticosteroids alone. It also came the limitations of prolonged systemic immunosuppressant usage in conjunctival-limbal allografts and keratolimbal allograft.

Limbal Stem Cell Deficiency: Demographics and Clinical Characteristics of a Large Retrospective Series at a Single Tertiary Referral Center

PURPOSE

The aim of this study was to characterize a large cohort of patients presenting to a single referral center for limbal stem cell deficiency (LSCD).

METHODS

A retrospective chart review of all patients with a clinical diagnosis of LSCD from 2002 to 2015 was performed. Demographics, etiology, previous ocular surgeries, visual acuity, and treatment were assessed.

RESULTS

Seven hundred thirty-eight eyes of 434 patients (51.4% male subjects) were diagnosed with LSCD. The mean presenting age was 42.9 years, 70% presented with bilateral disease, and overall vision was poor. The most common etiologies were congenital aniridia (30.9%), chemical or thermal injuries (20.6%), contact lens (16.8%), Stevens-Johnson syndrome (SJS, 10.4%), and iatrogenic (7.3%). Congenital aniridia had a significantly increased association with glaucoma or ocular hypertension (P < 0.0001). Chemical or thermal injuries (P = 0.0007), SJS (P < 0.0001), and mucous membrane pemphigoid (P < 0.0001) had a significantly increased association with eyelid pathology. The mean logMAR best corrected visual acuity (analysis excluded eyes with light perception and no light perception) at presentation was 1.145 (∼20/280). Keratoplasty performed (before presentation at our center) without first addressing the LSCD was seen in 80 eyes; all keratoplasties failed due to recurrence of the LSCD.

CONCLUSIONS

Patients presenting with LSCD were on average middle aged without sex predominance. LSCD was most commonly bilateral, comprised a wide range of etiologies, and decreased vision substantially. Ocular comorbidities may need to be treated before treating the LSCD surgically. Finally, not addressing the LSCD (primary issue) first can result in keratoplasty failure.

Aniridia and the ocular surface: Medical and surgical problems and solutions

Congenital aniridia is a multisystemic genetic disease due to a mutation in PAX6 gene which severely affects the development and functionality of the human eyes. In patients affected by the mutation, aside from the absence or defects of iris tissue formation, abnormalities in position or opacities of the crystalline lens, macular hypoplasia, ocular surface disease is the main cause of visual loss and the deterioration of the quality of life of most patients. Limbal stem cell deficiency combined with tear film instability and secondary dry eye cause aniridic keratopathy which, in advanced stages, ends up in corneal opacification. In this paper, the actual knowledge about congenital aniridia keratopathy physiopathology and medical and surgical treatment options and their efficacy are discussed. Indications and results of topical treatments with artificial tears and blood-derivatives in its initial stages, and different surgical techniques as limbal stem cell transplantation, keratoplasty and keratoprostheses are reviewed. Finally, recent advances and results in regenerative medicine techniques with ex vivo stem cell cultivation or other types of cultivated cells are presented.

Clinical Aspects of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis With Severe Ocular Complications in Brazil

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are acute and potentially fatal inflammatory vesiculobullous reactions that affect the skin and mucous membranes, and which are most often triggered by particular medications and infections. In Brazil, the drugs most frequently associated with TEN and SJS include cold medicine such as dipyrone and NSAIDs, followed by carbamazepine, phenobarbital, penicillin, and allopurinol. Genetic variations have been found to increase the risk of SJS/TEN in response to triggering factors such as medications. The most closely associated genes found in Brazilian cold-medicine-related SJS/TEN patients with severe ocular complications are HLA-A^*66:01 in those of mixed African and European ancestry and HLA-B^*44:03 and HLA-C^*12:03 in those of solely European ancestry. Our classification system for grading ocular surface complication severity in SJS/TEN patients revealed the most severe complications to be limbal stem cell deficiency and dry eye. Changes to the conjunctival flora have also been observed in SJS/TEN patients. Our group identified bacterial colonization in 95% of the eyes (55.5% of which were gram-positive cocci, 25.5% of which were gram-negative bacilli, and 19% of which were gram-positive bacilli). Several new treatment options in the acute and chronic ocular management of the SJS/TEN patients have been described. This article highlights some Brazilian institutions' contributions to ocular surface care in both the acute phase (including the use of amniotic membrane transplantation) and the chronic phase (such as eyelid margin and fornix reconstruction, minor salivary gland transplantation, amniotic membrane and limbal transplantation, scleral contact lenses, anti-angiogenic eyedrops for corneal neovascularization, ex-vivo cultivated limbal epithelium transplantation, conjunctival-limbal autografting, oral mucosa transplantation, and keratoprosthesis).

Understanding Immune Responses to Surgical Transplant Procedures in Stevens Johnsons Syndrome Patients

Stevens Johnsons syndrome (SJS) is a mucocutaneous disorder caused by an autoimmune response most commonly to medications. Unless it is properly managed in the acute setting, this entity can affect the ocular surface causing chronic cicatrizing conjunctivitis with limbal stem cell deficiency and lid anomalies which ultimately result in corneal opacities that may limit patients' visual acuity. When this stage is reached, some patients might need to undergo some form of corneal and/or limbal stem cell transplantation that exposes an already sensitized immune system to a new alloantigen. While the innate immunity plays a role in corneal graft survival, adaptive immune responses play a major part in corneal graft rejection and failure, namely through CD4+ T cell lymphocytes. Hence, the management of the immune response to surgical transplant procedures in SJS patients, involves a dual approach that modulates the inflammatory response to a new alloantigen in the context of an autoimmune sensitized patient. This review will explore and discuss current perspectives and future directions in the field of ocular immunology on how to manage SJS immune responses to ocular surgical procedures, reviewing systemic and local immunosuppressive therapies and protocols to adequately manage this debilitating condition.

Corneal reconstruction in chemically damaged cornea using temperature responsive surface assisted mesenchymal stem cell transplantation in rabbits

PURPOSE

Transplantation of autologous stem cells over damaged cornea seems to be a promising approach for corneal reconstruction. Use of a biocompatible carrier is still a challenge in bedside translation of transplantation. We investigated corneal reconstruction and tissue remodelling by transplantation of mesenchymal stem cells (MSCs) using temperature responsive membranes in chemically damaged rabbit cornea model.

METHODS

MSCs were cultured from rabbit's bone marrow and transplanted over alkali injured cornea, using either temperature responsive membrane or fibrin glue method. Endogenous levels of MSCs were assessed to decide the optimal time point for transplanting cells. MSC transplanted corneas were harvested at different time points post-transplantation. Corneal repair markers were evaluated using histopathology, immunohistochemistry (IHC) and real time qPCR. The quality of cornea reconstructed was evaluated and compared using corneal opacity scoring and immunohistochemistry (IHC).

RESULTS

Use of temperature responsive surface as carrier resulted in uniform and homogenous delivery of MSCs sheet over the damaged corneal surface. Corneal transparency improved day 7 onwards post-MSC transplantation in rabbit chemically injured cornea. Complete re-epithelialization of injured cornea was observed 15 days after MSC transplantation. Restoration of vimentin, α-smooth muscle actin and collagen levels in MSC transplanted cornea was observed post-transplantation. Further, differentiation of MSCs into mature corneal epithelial cells was also observed upon transplantation.

CONCLUSIONS

The extent of corneal repair was apparently better using temperature responsive surfaces. The surface provides biocompatible niche for MSCs and can be a method of choice in clinics for cell transplantation over the damaged ocular surfaces.

Clinical Outcomes of Allogeneic Ocular Surface Stem Cell Transplantation in Pediatric Patients

PURPOSE

To describe the outcomes of allograft ocular surface stem cell transplantation (OSST) and the complication profile of systemic immunosuppression (SI) in pediatric patients with limbal stem cell deficiency.

METHODS

This was a retrospective interventional case series from a single tertiary referral institution of 20 eyes from 13 patients who 1) underwent allograft OSST surgery, 2) were 18 years or less at time of OSST, and 3) received SI with 4) a minimum of 12-months follow-up. The main outcome measures were ocular surface stability, visual acuity, and SI adverse events.

RESULTS

The mean age of patients was 15.1 ± 3.2 years (range 9-18 years). The mean follow-up was 5.6 ± 5.0 years after OSST. At the last follow-up, 15 eyes (75%) had a stable ocular surface, 1 eye (5%) developed partial failure, and 4 eyes (20%) developed total surface failure. Preoperative mean logarithm of the minimum angle of resolution visual acuity 1.5 improved to 1.1 at the last follow-up (P = 0.1); when 4 eyes of 3 nonadherent patients were excluded, the results were more pronounced and statistically significant (1.5 improved to 1.0, P = 0.002). SI was tolerated well by all patients with minimal adverse events.

CONCLUSIONS

OSST provides a stable ocular surface and is a successful treatment option for pediatric patients with limbal stem cell deficiency. SI is well-tolerated with a minimal complication profile.

Surgical Management of Limbal Stem Cell Deficiency

Treatment of limbal stem cell deficiency is challenging. Multiple options can be adopted according to the underlying cause and the patient and physician preferences. Stem cell transplant is a common treatment modality and several techniques have been described with outcomes varying by the laterality of the condition. Keratoprosthesis is a preferred option for bilateral conditions. Indications for type 1 and type 2 keratoprosthesis differ and the past 2 decades have seen a revolution in the field of keratoprosthesis with encouraging and improved outcomes. Management also includes preventive measures and measures to optimize/stabilize the ocular surface that would go a long way in reducing the deterioration of the ocular surface. The aim of this review is to provide an overview of the currently available techniques and to present a comprehensive algorithm to assist in decision making for unilateral and bilateral limbal stem cell deficiency.

Use of Panel-Reactive Antibody Testing in the Planning and Management of Ocular Surface Stem Cell Transplantation

PURPOSE

Panel-reactive antibody (PRA) testing has been widely adopted in solid organ transplantation for risk assessment in potential allograft recipients but has not been studied in the context of ophthalmic transplantation. The purpose of this study is to evaluate outcomes in patients undergoing ocular surface stem cell transplantation (OSST) for limbal stem cell deficiency (LSCD) relative to preoperative PRA level.

METHODS

This is retrospective chart review of all eyes with documented PRA level that underwent OSST for LSCD between May 2000 and March 2019 at a single institution. Eyes with stable ocular surface but <1 year of follow-up and eyes without updated PRA before repeat OSST were excluded. Eyes were grouped by PRA <80% and ≥80%. The primary outcome was ocular surface failure, whereas the secondary outcome was clinical allograft rejection.

RESULTS

Sixty-nine surgeries met inclusion criteria, consisting of 54 living-related conjunctival limbal allografts, 5 keratolimbal allografts, and 10 combined living-related conjunctival limbal allografts/keratolimbal allografts (Cincinnati procedure). The most common etiologies for LSCD were aniridia (33%), chemical/thermal injury (28%), and contact lens associated (14%). Surface failure occurred in 5 of 12 eyes (58%) with PRA ≥80% versus 12 of 57 eyes (21%) with PRA <80% (P = 0.01). The relative risk for surface failure with PRA ≥80% was 2.8 [confidence interval (CI), 1.38-5.55]. There was no significant difference in acute rejection (P = 1).

CONCLUSIONS

Pretransplant PRA level is an important prognostic factor for ocular surface stability in eyes undergoing OSST for LSCD, with implications for donor selection, perioperative management, and systemic immunosuppression.

Cellular therapy of corneal epithelial defect by adipose mesenchymal stem cell-derived epithelial progenitors

Background

Persistent epithelial defects (PED), associated with limbal stem cell deficiency (LSCD), require ocular surface reconstruction with a stable corneal epithelium (CE). This study investigated CE reformation using human adipose mesenchymal stem cells (ADSC), which derived epithelial progenitors via mesenchymal-epithelial transition (MET).

Methods

STEMPRO human ADSC were cultured with specific inhibitors antagonizing glycogen synthase kinase-3 and transforming growth factor-β signaling, followed by culture under a defined progenitor cell targeted-epithelial differentiation condition to generate epithelial-like cells (MET-Epi), which were characterized for cell viability, mesenchymal, and epithelial phenotypes using immunofluorescence and flow cytometry. Tissue-engineered (TE) MET-Epi cells on fibrin gel were transplanted to corneal surface of the rat LSCD model caused by alkali injury. Epithelial healing, corneal edema, and haze grading, CE formation were assessed by fluorescein staining, slit lamp bio-microscopy, anterior segment optical coherence tomography, and immunohistochemistry.

Results

CD73^high/CD90^high/CD105^high/CD166^high/CD14^negative/CD31^negative human ADSC underwent MET, giving viable epithelial-like progenitors expressing δNp63, CDH1 (E-cadherin), epidermal growth factor receptor, integrin-β4, and cytokeratin (CK)-5, 9. Under defined epithelial differentiation culture, these progenitors generated MET-Epi cells expressing cell junction proteins ZO1 and occludin. When transplanted onto rat corneal surface with LSCD-induced PED, TE-MET-Epi achieved more efficient epithelial healing, suppressed corneal edema, and opacities, when compared to corneas without treatment or transplanted with TE-ADSC. CE markers (CK3, 12, and CDH1) were expressed on TE-MET-Epi-transplanted corneas but not in other control groups.

Conclusion

Human ADSC-derived epithelial-like cells, via MET, recovered the CE from PED associated with LSCD. ADSC can be a viable adult stem cell source for potential autologous epithelial cell-based therapy for corneal surface disorders.

Simple limbal epithelial transplantation: Current status and future perspectives

Damage to limbal stem cells as a result of injury or disease can lead to limbal stem cell deficiency (LSCD). This disease is characterized by decreased vision that is often painful and may progress to blindness. Clinical features include inflammation, neovascularization, and persistent cornea epithelial defects. Successful strategies for treatment involve transplantation of grafts harvested from the limbus of the alternate healthy eye, called conjunctival‐limbal autograft (CLAU) and transplantation of limbal cell sheets cultured from limbal biopsies, termed cultured limbal epithelial transplantation (CLET). In 2012, Sangwan and colleagues presented simple limbal epithelial transplantation (SLET), a novel transplantation technique that combines the benefits of CLAU and CLET and avoids the challenges associated with both. In SLET a small biopsy from the limbus of the healthy eye is divided and distributed over human amniotic membrane, which is placed on the affected cornea. Outgrowth occurs from each small explant and a complete corneal epithelium is typically formed within 2 weeks. Advantages of SLET include reduced risk of iatrogenic LSCD occurring in the healthy cornea at harvest; direct transfer circumventing the need for cell culture; and the opportunity to perform biopsy harvest and transplantation in one operation. Success so far using SLET is comparable with CLAU and CLET. Of note, 336 of 404 (83%) operations using SLET resulted in restoration of the corneal epithelium, whereas visual acuity improved in 258 of the 373 (69%) reported cases. This review summarizes the results of 31 studies published on SLET since 2012. Progress, advantages, challenges, and suggestions for future studies are presented.

Long-Term Results of Cultured Limbal Stem Cell Versus Limbal Tissue Transplantation in Stage III Limbal Deficiency

We aimed to evaluate efficiency and safety of transplantation of limbal stem cells (LSC) cultured on human amniotic membrane with no feeders and to compare cultured LSC with limbal tissue transplantation. Thirty eyes with stage III LSC deficiency were treated with autologous (autoLSC) or allogeneic (alloLSC) cultured LSC transplantation (prospective phase II clinical trial; average follow-up time, 72 months) or autologous (autoLT) or allogeneic (alloLT) limbal tissue transplantation (retrospective control group; average follow-up time, 132 months) between 1993 and 2014. The 5-year graft survival defined by absence of recurrence of the clinical signs of limbal deficiency was 71% for autoLSC, 0% for alloLSC, 75% for autoLT, and 33% for alloLT. Visual acuity improved by 9.2 lines for autoLSC and 3.3 lines for autoLT. It decreased by 0.7 lines for alloLSC and 1.9 lines for alloLT. Adverse events were recorded in 1/7 autoLSC, 7/7 alloLSC, 6/8 autoLT, and 8/8 alloLT patients. Corneal epithelial defect was the only adverse event recorded after autoLSC, whereas severe sight-threatening adverse events were recorded in the remaining three groups. Compared with failed grafts, successful grafts featured greater decrease in fluorescein staining, greater superficial vascularization-free corneal area, lower variability of the corneal epithelial thickness, and higher corneal epithelial basal cell density. Autologous cultured LSC transplantation was associated with high long-term survival and dramatic improvement in vision and was very safe. Autologous limbal tissue transplantation resulted in similar efficiency but was less safe. Cadaver allogeneic grafts resulted in low long-term success rate and high prevalence of serious adverse events. Stem Cells Translational Medicine 2019;8:1230&1241.

Ocular surface system alterations in ocular graft-versus-host disease: all the pieces of the complex puzzle

PURPOSE

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cells transplantation, occurring in about half of transplanted patients. This condition seems to be the result of a progressive immune-mediated damage that can involve various tissues, including the eyes. The ocular surface system is the ocular structure most frequently impaired, and dry eye disease is considered the hallmark of ocular GVHD. Given the increasing prevalence and the frequent severe involvement of the ocular surface with vision-threatening complications, ocular GVHD represents a current diagnostic and therapeutic challenge. The purpose of this literature review is to describe all the clinical manifestations occurring in the setting of ocular GVHD, and to further report the outcomes of conventional and novel therapies.

METHODS

A literature search about ocular GVHD was performed in PubMed, Scopus, Medline databases, and ClinicalTrials.gov as well as through the reference lists of identified publications until January 2019. We have included RCTs, prospective observational studies, prospective and retrospective cohort studies, pilot studies, and review articles.

RESULTS

Overall, 107 articles, 3 book chapters, and 6 ongoing registered clinical trials were collected and analyzed. Ocular GVHD can affect all the structures of the entire ocular surface system, including lacrimal and meibomian glands, cornea, conjunctiva, eyelids, nasolacrimal duct, and tears. Current medical treatment is mainly focused on lubrication and control of drainage, tear evaporation, and ocular surface inflammation. Surgical treatment may be necessary in severe, recalcitrant, or complicated cases. Amniotic membrane and tectonic keratoplasty can be valid options to restore the integrity of the cornea. Recently, conjunctival and limbal transplantation from the same living-related bone marrow donor has been proposed to manage both dry eye and limbal stem cell deficiency, without any risk of immunologic rejection.

CONCLUSION

This review provides an up-to-date analysis on clinical findings and current and future management of ocular GVHD. A correct and prompt diagnosis along with an appropriate and aggressive treatment are fundamental for avoiding the occurrence of vision-threatening complications.

Infectious Keratitis After Ocular Surface Stem Cell Transplantation

PURPOSE

To describe the rate, clinical/microbiological characteristics, and outcomes of infectious keratitis in eyes with limbal stem cell deficiency after ocular surface stem cell transplantation (OSST).

METHODS

In this retrospective chart review of 278 eyes that underwent OSST between January 2006 and December 2016, eyes treated for previous infectious keratitis (bacterial, fungal, or viral) were included. Demographics, risk factors, course, microbiological characteristics, and outcomes were assessed.

RESULTS

A total of 52 eyes (18.7%) of 48 patients (28 men and 20 women) developed 75 episodes (culture-proven or presumed) of infectious keratitis (range 1-4 episodes) with mean follow-up of 5.3 ± 3.6 years after OSST. The most common limbal stem cell deficiency etiologies included chemical/thermal (27 episodes), Stevens-Johnson syndrome (19 episodes), aniridia (8 episodes), and mucous membrane pemphigoid (8 episodes). There were 44 (58.7%) bacterial keratitis episodes, 24 (32%) fungal keratitis episodes, and 7 (9.3%) HSV keratitis episodes. Gram-positive bacteria (79%) and Candida species (73%) were the most common bacterial and fungal pathogens. Before infection, 33% had an epithelial defect, 69% had a bandage contact lens, 91% were on systemic immunosuppression, and 25% recently had undergone ocular surgery (<3 months). Although 75% resolved with antimicrobial treatment, 25% required a therapeutic keratoplasty (TPK; 2 cases needed multiple TPK).

CONCLUSIONS

Despite successful OSST surgery, infectious keratitis is relatively common, and aggressive medical/surgical therapy is warranted. Prophylactic topical antibiotics and a cicatrizing conjunctivitis diagnosis may account for the high proportion of fungal keratitis in this population.

Emerging Therapeutic Strategies for Limbal Stem Cell Deficiency

Identification and characterization of the limbal epithelial stem cells (LESCs) has proven to be a major accomplishment in anterior ocular surface biology. These cells have been shown to be a subpopulation of limbal epithelial basal cells, which serve as the progenitor population of the corneal epithelium. LESCs have been demonstrated to play an important role in maintaining corneal epithelium homeostasis. Many ocular surface diseases, including intrinsic (e.g., Sjogren's syndrome) or extrinsic (e.g., alkali or thermal burns) insults, which impair LESCs, can lead to limbal stem cell deficiency (LSCD). LSCD is characterized by an overgrowth of conjunctival-derived epithelial cells, corneal neovascularization, and chronic inflammation, eventually leading to blindness. Treatment of LSCD has been challenging, especially in bilateral total LSCD. Recently, advances in LESC research have led to novel therapeutic approaches for treating LSCD, such as transplantation of the cultured limbal epithelium. These novel therapeutic approaches have demonstrated efficacy for ocular surface reconstruction and restoration of vision in patients with LSCD. However, they all have their own limitations. Here, we describe the current status of LSCD treatment and discuss the advantages and disadvantages of the available therapeutic modalities.

Outcomes of Keratoplasty After Ocular Surface Stem Cell Transplantation

PURPOSE

To investigate the long-term outcomes of penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) after ocular surface stem cell transplantation (OSST).

METHODS

An observational retrospective review was performed on all patients who underwent OSST followed by either PK or DALK with a minimum of 6-month follow-up.

RESULTS

One hundred two eyes fulfilled the inclusion criteria. The mean time to keratoplasty after OSST was 19 months, and the mean follow-up was 57 months after keratoplasty. A Kaplan-Meier analysis demonstrated 92% graft survival at year 1, 77% at year 2, 62% at year 3, 55% at year 4, and 54% at year 5. During the study period, a total of 44 grafts failed. The mean time to graft failure was 32 months. Preoperative median best-corrected visual acuity for all eyes was 20/550, which improved to 20/100 (P < 0.001) at 1 year postoperatively, 20/60 (P < 0.001) at 2 years, and 20/100 (P < 0.001) at last follow-up.

CONCLUSIONS

Without addressing the underlying stem cell deficiency, keratoplasty in patients with total limbal stem cell deficiency will ultimately fail in all cases. OSST with either subsequent PK or DALK provides successful visual outcomes with an acceptable complication profile.

Probable Donor-Derived Cytomegalovirus Disease After Keratolimbal Allograft Transplantation

PURPOSE

To report a case of probable donor-derived cytomegalovirus (CMV) infection after keratolimbal allograft (KLAL) transplantation.

METHODS

Observational case report.

RESULTS

A 41-year-old man with a history of aniridic keratopathy and limbal stem cell deficiency underwent KLAL in his right eye. Preoperatively, he was negative for CMV IgG and IgM. Postoperatively, he was maintained on tacrolimus and mycophenolate mofetil for systemic immunosuppression; he was also on prophylactic valganciclovir (for CMV) and trimethoprim/sulfamethoxazole (for pneumocystis pneumonia) for 1 month. Approximately 5 weeks postoperatively, he developed a nonproductive cough, rhinorrhea, and dyspnea. His condition did not improve with oral azithromycin or levofloxacin. He developed worsening symptoms over the next 2 weeks despite therapy. The serum CMV polymerase chain reaction was positive, and he was readministered valganciclovir with subsequent resolution of symptoms.

CONCLUSIONS

We present the first case of CMV disease in a seronegative patient who received a presumed CMV-seropositive donor KLAL. Similar to solid organ transplantation, prophylactic and therapeutic management of CMV infection is necessary in the setting of systemic immunosuppression.

Combined Conjunctival Limbal Autografts and Living-Related Conjunctival Limbal Allografts for Severe Unilateral Ocular Surface Failure

PURPOSE

To describe the technique and present 2 cases of a combined conjunctival limbal autograft (CLAU) and living-related conjunctival limbal allograft (lr-CLAL) procedure for treatment of severe unilateral ocular surface failure.

METHODS

Interventional case series of 2 eyes of 2 patients sustaining severe thermal/chemical injuries from firework explosions. They both underwent the combined CLAU/lr-CLAL procedure followed by penetrating keratoplasty. Systemic immunosuppression consisted of oral tacrolimus and mycophenolate mofetil.

RESULTS

Preoperative vision was counting fingers for both patients, whereas visual acuity at last follow-up ranged between 20/40 and 20/50. Both patients maintained a stable surface at last follow-up without any episodes of rejection. Patients tolerated systemic immunosuppression well without any persistent adverse reactions.

CONCLUSIONS

Certain etiologies of limbal stem cell deficiency also lead to significant conjunctival (and goblet cell) deficiency. Combined CLAU and lr-CLAL procedures maximize the amount of healthy limbal stem cells with conjunctiva while also minimizing the antigenic burden as all transplanted tissue potentially can be a complete (or near-complete), compatible HLA and crossmatch.

Systemic immunosuppression in limbal stem cell transplantation: best practices and future challenges

The objective of this study was to evaluate systemic immunosuppression regimens used for patients undergoing ocular surface stem cell transplantation, including their benefits and adverse effects in the adjunctive management of limbal stem cell deficiency (LSCD). A systematic literature review was conducted using the MEDLINE and EMBASE databases (1980-2015). Data were collected on surgical intervention(s), type of immunosuppressive agent(s), duration of immunosuppression, percentage with stable ocular surface at last follow-up, mean follow-up time, and demographics. Data were also collected on adverse ocular and systemic outcomes. Sixteen reports met the inclusion criteria. There were no randomized controlled studies. Three studies were noncomparative prospective case series, whereas the majority were retrospective case series. Bilateral severe LSCD was the most common disease (50%), and keratolimbal allograft was the most common intervention (80%). Immunosuppressive regimens showed a progression from early studies using oral cyclosporine to later studies using combinations of mycophenolate mofetil and tacrolimus. Most studies included a course of high-dose systemic corticosteroids. For patients adherent to long-term systemic immunosuppression, stable ocular surface rates of 70%-80% at last follow-up were reported. Adverse effects included hypertension, diabetes mellitus, and biochemical abnormalities managed with pharmacotherapy or discontinuation of offending agents. There were no cases of mortality related to immunosuppression. However, the current literature does not elucidate which immunosuppressive regimen is most efficacious for different categories of LSCD or graft types. Evidence-based guidelines for systemic immunosuppression in limbal allograft therapy would benefit from randomized controlled and/or additional prospective studies. Long-term immunosuppression would benefit from close collaboration between ophthalmologists and transplant specialists to individualize treatments.

Angiogenesis and lymphangiogenesis in corneal transplantation-A review

Corneal transplantation has been proven effective for returning the gift of sight to those affected by corneal disorders such as opacity, injury, and infections that are a leading cause of blindness. Immune privilege plays an important role in the success of corneal transplantation procedures; however, immune rejection reactions do occur, and they, in conjunction with a shortage of corneal donor tissue, continue to pose major challenges. Corneal immune privilege is important to the success of corneal transplantation and closely related to the avascular nature of the cornea. Corneal avascularity may be disrupted by the processes of angiogenesis and lymphangiogenesis, and for this reason, these phenomena have been a focus of research in recent years. Through this research, therapies addressing certain rejection reactions related to angiogenesis have been developed and implemented. Corneal donor tissue shortages also have been addressed by the development of new materials to replace the human donor cornea. These advancements, along with other improvements in the corneal transplantation procedure, have contributed to an improved success rate for corneal transplantation. We summarize recent developments and improvements in corneal transplantation, including the current understanding of angiogenesis mechanisms, the anti-angiogenic and anti-lymphangiogenic factors identified to date, and the new materials being used. Additionally, we discuss future directions for research in corneal transplantation.

Long-term Outcomes of Ocular Surface Stem Cell Allograft Transplantation

PURPOSE

To investigate the long-term outcomes of ocular surface stem cell allograft transplantation (OSST) in patients with total limbal stem cell deficiency (LSCD) owing to various etiologies with a follow-up ≥ 5 years.

DESIGN

Retrospective interventional cohort.

METHODS

Setting: Single tertiary referral hospital.

STUDY POPULATION

Patients who had (1) presence of total LSCD, (2) surgical treatment with at least 1 allograft OSST procedure, and (3) minimum follow-up ≥ 5 years after OSST.

INTERVENTION

All patients underwent allograft OSST from March 1998 to June 2009. All patients received systemic immunosuppression.

MAIN OUTCOME MEASURES

Ocular surface stability, best-corrected visual acuity (BCVA).

RESULTS

A total of 165 eyes of 110 patients fulfilled the inclusion criteria with a mean follow-up period of 109.22 ± 35.7 months or approximately 9.1 years (range 5.2-17.7 years). Ocular surface stability was achieved in 72.7% (120/165) of eyes at last follow-up, while 15.2% (25/165) maintained an improved ocular surface and 12.1% (20/165) developed total surface failure. Additional OSST surgery was necessary in 30.9% (51/165 eyes) to maintain a stable ocular surface. There was ≥ 2 lines BCVA improvement in 62.1%, no change in 7.7%, and a worsened BCVA in 18.6% at last follow-up.

CONCLUSIONS

With proper immunosuppression and repeat procedure in case of failure, allograft OSST can provide true long-term ocular surface stability and successful visual outcomes.

Limbal Stem Cell Transplantation and Complications

Corneal epithelial stem cells are adult somatic stem cells located at the limbus and represent the ultimate source of transparent corneal epithelium. When these limbal stem cells become dysfunctional or deficient, limbal stem cell deficiency (LSCD) develops. LSCD is a major cause of corneal scarring and is particularly prevalent in chemical and thermal burns of the ocular surface. LSCD leads to conjunctivalization of the corneal surface, neovascularization, recurrent or persistent epithelial defects, ocular surface inflammation, and scarring that, in turn, lead to decreased vision, pain, and impaired quality of life. Several techniques have been reported for limbal stem cell transplantation (LSCT). We introduce the surgical techniques, examine the success rate, and discuss the postoperative complications of conjunctival limbal autograft (CLAU), cultivated limbal stem cell transplantation (CLET), simple limbal epithelial transplantation (SLET), and limbal allograft, including keratolimbal allografts (KLAL) and living-related conjunctival allograft (LR-CLAL).

Late Acute Rejection After Allograft Limbal Stem Cell Transplantation: Evidence for Long-Term Donor Survival

PURPOSE

To describe the clinical presentation and management of late (>3.0 years) acute graft rejection in keratolimbal allograft (KLAL) recipients.

METHODS

This was a multicenter, retrospective observational case series. Six eyes of 6 patients with ocular surface transplant at a mean age of 36.2 years were seen at 3 tertiary referral centers for acute graft rejection between 2007 and 2013. Main outcome measures included strength of systemic immunosuppression (SI) at the time of rejection, time to rejection, and clinical presentation of rejection.

RESULTS

Preoperative diagnoses included total limbal stem cell deficiency because of aniridia (n = 2) or chemical injury (n = 4). After an initially successful outcome, patients experienced late acute graft rejection at a mean time of 67.8 ± 24.1 months (range: 41-98) after KLAL while receiving suboptimal levels of SI because of medication taper (n = 5) or noncompliance (n = 1). Objective findings included an epithelial rejection line (n = 6), edema (n = 2), corneal epithelial irregularities (n = 2), and neovascularization (n = 1). Antirejection management consisted of topical corticosteroids (n = 6) and augmentation of SI therapy (n = 5).

CONCLUSIONS

These cases of late acute graft rejection in KLAL patients support the notion that allodonor cells can persist over the long run and remain at risk for immunologic rejection. It further underscores the fact that long-term success with KLAL may require extension of SI beyond the first few years, albeit at lower levels individualized to each patient.

Keratolimbal allograft

PURPOSE OF REVIEW

Keratolimbal allograft (KLAL) transplants limbal tissue attached to a corneoscleral carrier from a cadaveric donor to deliver a large number of stem cells to the recipient. The present article will provide a review of KLAL focusing on the recent literature.

RECENT FINDINGS

Recent findings pertain to tissue selection, immunosuppression and adverse event profiles, and postoperative complications (particularly related to immunologic rejection).

SUMMARY

KLAL permits the treatment of limbal stem cell deficiency eyes when there is no available living-related or autograft tissue with minimal risk of irreversible toxicity from modern systemic immunosuppression. The prevention of immunologic graft rejection with the use of systemic immunosuppression after KLAL is critical and may require extending systemic immunosuppression treatment longer than previously thought. With vigilant postoperative management, KLAL can allow successful treatment of the most severely diseased eyes.