Combined penetrating keratoplasty and keratolimbal allograft transplantation in comparison with corneoscleral transplantation in the treatment of severe eye burns

The Use of Corneoscleral Grafts to Maintain Tectonic Stability in Severe Keratolysis

Severe corneal ulcerations, causing major keratolysis with large perforation of the cornea or extending to the limbal region, are an ophthalmic emergency. In these cases, a larger corneoscleral graft can be transplanted to restore tectonic integrity, alleviate pain, save vision, and prevent loss of the eye. Chart review of 34 patients with a corneoscleral graft ≥9.5 mm was conducted. Primary endpoints of the study were tectonic stability defined as no need for another keratoplasty or enucleation. In addition, visual acuity, postoperative complications, and secondary procedures were analyzed. In total, 12 patients (35%) were female. The mean age at transplantation was 65 ± 19 years. The underlying disease was a perforated infectious corneal ulcer in 30 cases (88%). Mean follow up was 675 ± 789 days. Tectonic stability at the end of the follow-up was maintained with a probability of 56% in a Kaplan-Meier analysis. Another penetrating keratoplasty was necessary in six cases (17%) and enucleation in five cases (15%). A corneoscleral transplant remains a viable treatment option to prevent enucleation in severe keratolysis. In our study, this was possible in about half of the cases. Postoperative complications, secondary surgeries, and markedly reduced visual acuity put the advantages into perspective.

Outcomes of Combined Penetrating Keratoplasty and Limbal Stem Cell Transplantation: A Meta-Analysis on Simultaneous Versus Sequential Surgery

PURPOSE

The objective of this study is to perform a systematic review and meta-analysis of the published studies on limbal stem cell transplantation (LSCT) combined with penetrating keratoplasty (PK) performed either simultaneously or sequentially.

METHODS

An extensive search was conducted in the MEDLINE and Google Scholar databases. Prospective and retrospective trials and case series reporting on the outcomes of LSCT with PK were included. Primary outcomes were the stability of the ocular surface and the rejection and/or failure of the corneal graft.

RESULTS

A total of 209 eyes from 13 studies were included in the simultaneous group and 489 eyes from 33 studies in the sequential group. Ocular surface stability was 88% [95% confidence interval (CI), 79%-96%] for sequential cases and 64% (95% CI, 43%-82%) for simultaneous cases ( P = 0.001). The graft failure rate was 15% (95% CI, 6%-26%) for sequential cases and 44% (95% CI, 31%-58%) for simultaneous cases ( P < 0.001). For cases performed sequentially, subgroup analysis revealed a stable ocular surface in 97% (95% CI, 91%-100%) of autograft cases and 63% (95% CI, 45%-80%) of allograft cases ( P < 0.001). The graft failure rate in sequential cases was 7% (95% CI, 0%-18%) for autografts and 34% (95% CI, 18%-52%) for allografts ( P < 0.001).

CONCLUSIONS

Sequential LSCT followed by PK demonstrated superior results in terms of ocular surface stability and graft retention compared with simultaneous LSCT and PK. Limbal stem cells of autologous origin fare better than allogeneic ones in sequential cases.

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.

Cell jamming, stratification and p63 expression in cultivated human corneal epithelial cell sheets

Corneal limbal epithelial stem cell transplantation using cultivated human corneal epithelial cell sheets has been used successfully to treat limbal stem cell deficiencies. Here we report an investigation into the quality of cultivated human corneal epithelial cell sheets using time-lapse imaging of the cell culture process every 20 minutes over 14 days to ascertain the level of cell jamming, a phenomenon in which cells become smaller, more rounded and less actively expansive. In parallel, we also assessed the expression of p63, an important corneal epithelial stem cell marker. The occurrence of cell jamming was variable and transient, but was invariably associated with a thickening and stratification of the cell sheet. p63 was present in all expanding cell sheets in the first 9 days of culture, but it's presence did not always correlate with stratification of the cell sheet. Nor did p63 expression necessarily persist in stratified cell sheets. An assessment of cell jamming, therefore, can shed significant light on the quality and regenerative potential of cultivated human corneal epithelial cell sheets.

Long-Term Outcomes of Allogeneic Ocular Surface Reconstruction: Keratolimbal Allograft (KLAL) Followed by Penetrating Keratoplasty (PK)

Purpose

Long-term results of the patients with total LSCD, who had undergone keratolimbal allograft (KLAL) for limbal reconstruction followed by penetrating keratoplasty (PK).

Methods

The study analyzes surgical treatment of 43 eyes with severe ocular surface disorders. All subjects underwent KLAL to achieve suitable conditions for consecutive PK. Due to failures of primary treatment in 17 eyes (39%), the KLAL was repeated. PK was performed in all the patients at 9-12 months after KLAL. As a retrospective study we analyzed data from the medical records including the preoperative and postoperative best corrected visual acuity, corneal clarity, surgical outcomes and complications, postoperative intraocular pressure, graft rejection, and other comorbidities and complications.

Results

The preoperative visual acuity ranged from light perception to 0.01. The final improvement of visual acuity within a gain of one or more lines with the Snellen chart, including the results of successive surgical treatments after PK, was achieved in 23 operated eyes (53%). Early graft rejection was observed in 4 eyes (9%). In 3 eyes, it was manifested as endothelial rejection, and in 1 eye, as combined endothelial and epithelial rejection. PK failure requiring repetitive PK was present in 14 eyes (32%). Phthisis bulbi developed in 6 eyes (14%). Glaucoma or ocular hypertension was reported in 25 eyes (58%). A majority were treated with up to 3 topical agents or referred for trabeculectomy in 3 cases, transscleral cyclophotocoagulation in 2 eyes, and EX-PRESS glaucoma shunt implantation in 3 cases.

Conclusions

Successful KLAL carries a high risk of subsequent PK failure. Visual function remains the second aim of treatment; the primary one is to stabilize the surface.

Femtosecond Laser-Assisted Keratolimbal Allograft Transplantation for the Treatment of Total Limbal Stem Cell Deficiency

PURPOSE

To investigate the surgical procedure and therapeutic efficacy of femtosecond (FS) laser-assisted keratolimbal allograft (KLAL) transplantation in the treatment of eyes with total limbal stem cell deficiency.

METHODS

Ten eyes from 10 patients who underwent FS laser-assisted KLAL transplantation were enrolled. The best-corrected visual acuity (BCVA), ocular surface stability, corneal transparency, and postoperative complications were recorded.

RESULTS

The keratolimbal grafts prepared using the FS laser were even in thickness and width. After the surgery, glucocorticoid and tacrolimus eye drops were administered locally to the eyes with concentration gradients, and a medium dose was prescribed for maintenance. Within the mean follow-up period of 16.8 ± 7.3 months, 9 of 10 eyes (90.0%) maintained a stable ocular surface and showed significant improvements in corneal transparency and BCVA. Persistent corneal edema only occurred in one eye because of repeated epithelial defects, and the BCVA of this eye did not improve. Confocal microscopy revealed activated dendritic cells in the Bowman membrane at the limbus, but they were always low in density with small dendritic processes. No acute immune rejection, cataracts, or elevation of intraocular pressure were detected.

CONCLUSIONS

The FS laser-assisted KLAL technique can produce ring-shaped grafts with an even depth and width, resulting in a stable ocular surface and good visual prognosis. After surgery, glucocorticoids and potent immunosuppressive eye drops were administered locally with concentration gradients and effectively inhibited acute immune rejection.

Diagnostic criteria for limbal stem cell deficiency before surgical intervention-A systematic literature review and analysis

An accurate diagnosis of limbal stem cell deficiency (LSCD) is the premise of an appropriate treatment; however, there is no consensus about the diagnostic criteria for LSCD. We performed a systematic literature search of the peer-reviewed articles on PubMed, Medline, and Ovid to investigate how LSCD was diagnosed before surgical intervention. The methods used to diagnose LSCD included clinical presentation, impression cytology, and in vivo confocal microscopy. Among 131 eligible studies (4054 eyes), 26 studies (459 eyes, 11.3%) did not mention the diagnostic criteria. In the remaining 105 studies, the diagnosis of LSCD was made on the basis of clinical examination alone in 2398 eyes (62.9%), and additional diagnostic tests were used in 1047 (25.8%) eyes. Impression cytology was used in 981 eyes (24.2%), in vivo confocal microscopy was used in 29 eyes (0.7%), and both impression cytology and in vivo confocal microscopy were used in 37 eyes (0.9%). Our findings suggest that only a small portion of patients underwent a diagnostic test to confirm the diagnosis of LSCD. Treating physicians should be aware of the limitations of clinical examination in diagnosing LSCD and perform a diagnostic test whenever possible before surgical intervention.

The application of human amniotic membrane in the surgical management of limbal stem cell deficiency

The application of human amniotic membrane (AM) has a wide spectrum of indications in the treatment of ocular surface disorders. Transplantation of AM has been incorporated routinely as a component of ocular surface reconstruction in a variety of ocular pathologies. The application of human AM can be combined with nearly all types of limbal transplantation in treating limbal stem cell deficiency (LSCD). AM provides support and possible protection to the transplanted limbal tissues and limbal stem cells owing to its mechanical and biological properties, and these properties are thought to enhance the success rate of LSC transplantation. This paper reviews the current literature on the applications of AM in the surgical management of LSCD and summarizes the outcome of different surgical approaches. The current literature contains mostly low-level evidences in supporting the role of AM. The efficacy of AM in LSC transplantation needs to be confirmed by randomized controlled clinical trials.

Total Penetrating Keratoplasty: Indications, Therapeutic Approach, and Long-Term Follow-Up

Purpose

Evaluation of the indications, anatomical and functional results, and complications of total penetrating keratoplasty (TPK) in disorders involving whole cornea.

Materials and Methods

We analyzed outcomes of the surgical treatment of 47 eyes of 46 patients that underwent TPK. Indications were infectious keratitis, autoimmune disease, injury of the eyeball (mainly chemical burns), and other combined disorders. The surgical technique involved dissection of affected tissues with a margin of 1.0 mm. The size of the corneal graft ranged from 10.0 to 14.0 mm. We analyzed indications, outcomes, and complications of surgery.

Results

Final restoration of the ocular integrity and maintenance of the globe were achieved in 27 eyes (57%). More than one surgery was necessary in a total of 29 eyes (62%). The frequency of retransplantations did not vary significantly between the groups with different causes of corneal melting/perforation (63% of eyes with infection, 66% of eyes after trauma and 70% of eyes of patients with autoimmune disorders). Surgical treatment failed in 20 eyes (43%). Evisceration was necessary in 13 eyes (28%), phthisis occurred in 7 cases (15%).

Conclusion

TPK should be considered as a last line treatment in huge corneal destruction to restore integrity of the eye globe.

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).

Keratolimbal allograft for limbal stem cell deficiency after severe corneal chemical injury: a systematic review

Purpose

To review the published literature on outcomes of keratolimbal allograft (KLAL) for the surgical treatment of limbal stem cell deficiency (LSCD) and corneal blindness after severe corneal chemical injury.

Methods

Literature searches were conducted in the following electronic databases: MEDLINE, EMBASE, Science Citation Index, CINAHL, LILACS and the Cochrane Library. Standard systematic review methodology was applied. The main outcome measure was the proportion of eyes with best-corrected visual acuity (BCVA) ≥20/200 at last follow-up. Other measures of allograft success were also collected.

Results

We identified six reports in which KLAL outcomes in the eyes after chemical injury could be distinguished. There were no randomised controlled studies. The outcomes of KLAL in 36 eyes of 33 patients were analysed. One study with seven eyes did not specify KLAL follow-up specific to chemical injury. Median postoperative follow-up for the other 29 eyes in 26 patients was 42 months (range 6.2–114 months). In the same 29 eyes, 69% (20/29) had BCVA ≥20/200 at the last follow-up examination. Eighty-nine per cent of all eyes (32/36) underwent penetrating keratoplasty simultaneous or subsequent to KLAL.

Conclusions

The number of studies where outcomes of KLAL in eyes with severe corneal chemical injury could be discerned was limited, and variability was observed in outcome reporting. The quality of evidence to support the use of KLAL in LSCD in severe chemical corneal burns was low. Standardisation and longer follow-up are needed to better define evidence-based best practice when contemplating surgical intervention for blindness after corneal chemical injury.

PROSPERO registration number

CRD42017054733.

Long-Term Outcomes of the Boston Type I Keratoprosthesis in the Management of Corneal Limbal Stem Cell Deficiency

PURPOSE

To report the long-term outcomes of the Boston type I keratoprosthesis (KPro) in the management of limbal stem cell deficiency (LSCD).

METHODS

Retrospective review of KPro procedures performed by a single surgeon from May 1, 2004, to January 1, 2015.

RESULTS

One hundred seventy-three KPro procedures were performed in 149 eyes, including 68 in 54 eyes with LSCD. Glaucoma (48% vs. 82%, P < 0.0001) and a history of ≥2 keratoplasties (39% vs. 79%, P < 0.0001) were significantly less common in eyes with LSCD. Preoperative corrected distance visual acuity was ≥20/200 in 7% of eyes with LSCD and 9% of eyes without LSCD. A significantly greater percentage of eyes with LSCD had CDVA ≥ 20/200 at each of the first 5 years after surgery. The only postoperative complication more common in eyes with LSCD compared with eyes without was persistent corneal epithelial defect (50% vs. 28%, P = 0.013), although the associated secondary complications sterile corneal necrosis (22% vs. 11%, P = 0.059) and corneal infiltrate (20% vs. 10%, P = 0.08) were twice as common in eyes with LSCD. Despite this, the retention failure rates in eyes with and without LSCD were similar (0.089/eye-yr vs. 0.071/eye-yr; P = 0.53).

CONCLUSIONS

Boston type I keratoprosthesis implantation results in a significant improvement in CDVA in the majority of eyes with LSCD through 5 years after surgery, with better visual outcomes than eyes without LSCD. Although several postoperative complications are more common in LSCD, sight-threatening complications such as endophthalmitis and retinal detachment are not. Additionally, there is no difference in the retention failure rate in eyes with and without LSCD, although a larger number of procedures with longer follow-up will be needed to determine retention outcomes more than 5 years after surgery.

Outcomes of Boston keratoprosthesis implantation for failed keratoplasty after keratolimbal allograft

PURPOSE

To evaluate factors that contribute to keratoplasty failure after keratolimbal allograft (KLAL) and report the outcomes of Boston keratoprosthesis type I (KPro) as salvage therapy.

METHODS

Retrospective noncomparative case series of 7 eyes in 7 consecutive patients with ocular surface disease and limbal stem cell deficiency treated with KPro after failed KLAL. Mechanisms of graft failure, KPro device retention rate, and preoperative and postoperative best-corrected visual acuities were studied.

RESULTS

In the studied cohort, keratoplasty graft failure occurred at an average of 9.9 months (range, 1-17 months) after KLAL. Among the 7 eyes reviewed, 4 had tube shunts, 3 of which contributed directly to endothelial graft failure. One eye failed due to fungal keratitis, 1 eye failed due to immune-mediated endothelial rejection, and 2 eyes failed due to recurrent surface disease. During an average follow-up of 585 days (19.5 months) after KPro, best-corrected visual acuity improved from a median of counting fingers CF@2ft (range, hand motions to 20/400) to a median of 20/400 (range, CF@3ft to 20/25). There was 85.7% (6 of 7) retention of implanted devices at the last follow-up, with 1 eye requiring repeat KPro for corneal melt and implant extrusion after abrupt cessation of immunosuppression.

CONCLUSIONS

Despite successful KLAL outcomes and systemic immunosuppression, patients who undergo ocular surface reconstruction with KLAL are still at risk for subsequent keratoplasty failure. Keratoprosthesis is a viable salvage therapy for visual rehabilitation in these patients. Adequate immunosuppression is important in postoperative management of these patients.

Ophthalmic transplantology: anterior segment of the eye - part I

Background

Transplantology is a quickly developing field of ophthalmology. It currently is able to treat many inherited, degenerative, inflammatory, traumatic, and cancerous diseases. This review outlines recent concepts and methods of treating ocular diseases with tissue and cell grafts. Ocular transplants related to the anterior part of the eye, including the conjunctiva and the cornea, are reviewed in Part 1.

Material/Methods

The scientific literature dated from January 2005 to July 2011 was thoroughly searched using Medline and PubMed. Publications dated 2009, 2010, and 2011 were analyzed in detail. Search terms were as follows: auto-, homo-, heterologous transplantation, eyeball, ocular adnexa, anterior segment of the eye, cornea, lamellar keratoplasty, stem cells, cultured cells. Further data were found at the website of the Eye Bank Association of America.

Results

Nearly all tissues of the anterior segment of the eye (the conjunctiva, sclera, eye muscles, and cornea) are transplanted. Because of the recent significant progress in the field, cornea transplantation was analyzed in more detail, specifically procedures such as limbus grafts and anterior and posterior lamellar keratoplasty. Indications, advantages, and drawbacks of the transplant techniques were also reviewed.

Conclusions

Recent progress in the field of cornea transplants allows treatment at the level of the endothelium and the use of cultured limbal epithelial stem cell grafts. However, compared with previous techniques, modern and multilayered transplant techniques of the cornea require much more expertise and longer training of the surgeon, as well as expensive and technologically advanced equipment. The availability of donor tissue is still the main limitation affecting all transplants. Therefore, cell culturing techniques such as stem cells, as well as artificial cornea projects, seem to be very promising.

Long-term effectiveness of autologous cultured limbal stem cell grafts in patients with limbal stem cell deficiency due to chemical burns

BACKGROUND

Chemical burns cause depletion of limbal stem cells and eventually lead to corneal opacity and visual loss. We investigated the long-term effectiveness of autologous cultured limbal stem cell grafts in patients with limbal stem cell deficiency.

DESIGN

Prospective, non-comparative interventional case series.

PARTICIPANTS

Sixteen eyes from 16 patients with severe, unilateral limbal stem cell deficiency caused by chemical burns.

METHODS

Autologous ex vivo cultured limbal stem cells were grafted onto the recipient eye after superficial keratectomy.

MAIN OUTCOME MEASURES

Clinical parameters of limbal stem cell deficiency (stability/transparency of the corneal epithelium, superficial corneal vascularization and pain/photophobia), visual acuity, cytokeratin expression on impression cytology specimens and histology on excised corneal buttons.

RESULTS

At 12 months post-surgery, evaluation of the 16 patients showed that 10 (62.6%) experienced complete restoration of a stable and clear epithelium and 3 (18.7%) had partially successful outcomes (re-appearance of conjunctiva in some sectors of the cornea and instable corneal surface). Graft failure (no change in corneal surface conditions) was seen in three (18.7%) patients. Penetrating keratoplasty was performed in seven patients, with visual acuity improving up to 0.8 (best result). For two patients, regeneration of the corneal epithelium was confirmed by molecular marker (p63, cytokeratin 3, 12 and 19, mucin 1) analysis. Follow-up times ranged from 12 to 50 months.

CONCLUSIONS

Grafts of autologous limbal stem cells cultured onto fibrin glue discs can successfully regenerate the corneal epithelium in patients with limbal stem cell deficiency, allowing to perform successful cornea transplantation and restore vision.

Long-term outcome of cultivated oral mucosal epithelial sheet transplantation in treatment of total limbal stem cell deficiency

PURPOSE

To evaluate the long-term outcome of cultivated oral mucosal epithelial transplantation (COMET) in treatment of eyes with total limbal stem cell deficiency.

DESIGN

Noncomparative, retrospective, interventional case series.

PARTICIPANTS

Forty eyes in 36 patients with total limbal stem cell deficiency (Stevens-Johnson syndrome in 12 eyes, chemical or thermal burns in 11 eyes, ocular cicatricial pemphigoid [OCP] in 9 eyes, pseudo-OCP in 7 eyes, and gelatinous drop-like dystrophy in 1 eye) were treated at the Department of Ophthalmology, Tokyo Dental College, Chiba, Japan.

INTERVENTION

Cultivated autologous oral mucosal epithelial sheets were transplanted onto the ocular surface in eyes with total limbal stem cell deficiency.

MAIN OUTCOME MEASURES

Reconstruction of a stable ocular surface with a clear appearance and no epithelial defects, reduction in fibrovascular tissue invasion of corneal surface, a functional fornix, change in visual acuity, and postoperative complications.

RESULTS

The mean follow-up period was 25.5 months (range, 6-54.9 months). Kaplan-Meier analysis of a corneal surface stability revealed an early decline in transplanted oral mucosal epithelial stability over the first 6 months, remaining comparatively stable thereafter (1 year, 64.8%; 2 years, 59.0%; and 3 years, 53.1%). Postoperative persistent epithelial failure developed within the first 3 months in 9 eyes. Early epithelial failure was associated closely with preoperative corneal defects. Gradual fibrovascular tissue invasion of the corneal surface was observed in 8 eyes and was marked in cases of OCP. Survival of a functional fornix decreased progressively until approximately 6 months. Postoperative visual acuity seemed to be related to the presence of corneal opacity. Complications included stromal melting or perforation in 8 eyes, infectious keratitis in 2 eyes, glaucoma in 8 eyes, and recurrence of herpetic keratitis in 1 eye. Corneal melting or perforation and infectious keratitis were associated closely with persistent epithelial defects after COMET.

CONCLUSIONS

The transplantation of cultivated oral mucosal epithelial sheets offers a viable and safe alternative in the reconstruction of a stable ocular surface. Epithelialization of the corneal surface is very important not only in obtaining a satisfactory long-term outcome, but also in achieving a lower incidence of complications.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Anti-inflammatory protein TSG-6 reduces inflammatory damage to the cornea following chemical and mechanical injury

Previous reports demonstrated that adult stem/progenitor cells from bone marrow (multipotent mesenchymal stem cells; MSCs) can repair injured tissues with little evidence of engraftment or differentiation. In exploring this phenomenon, our group has recently discovered that the therapeutic benefits of MSCs are in part explained by the cells being activated by signals from injured tissues to express an anti-inflammatory protein TNF-α-stimulated gene/protein 6 (TSG-6). Therefore, we elected to test the hypothesis that TSG-6 would have therapeutic effects in inflammatory but noninfectious diseases of the corneal surface. We produced a chemical and mechanical injury of the cornea in rats by brief application of 100% ethanol followed by mechanical debridement of corneal and limbal epithelium. Recombinant human TSG-6 or PBS solution was then injected into the anterior chamber of the eye. TSG-6 markedly decreased corneal opacity, neovascularization, and neutrophil infiltration. The levels of proinflammatory cytokines, chemokines, and matrix metalloproteinases were also decreased. The data indicated that TSG-6, a therapeutic protein produced by MSCs in response to injury signals, can protect the corneal surface from the excessive inflammatory response following injury.