The Orphan Drug for Acanthamoeba Keratitis (ODAK) Trial: PHMB 0.08% (Polihexanide) and Placebo versus PHMB 0.02% and Propamidine 0.1.

PURPOSE: To compare topical PHMB (polihexanide) 0.02% (0.2 mg/ml)+ propamidine 0.1% (1 mg/ml) with PHMB 0.08% (0.8 mg/ml)+ placebo (PHMB 0.08%) for Acanthamoeba keratitis (AK) treatment. DESIGN: Prospective, randomized, double-masked, active-controlled, multicenter phase 3 study (ClinicalTrials.gov identifier, NCT03274895). PARTICIPANTS: One hundred thirty-five patients treated at 6 European centers. METHODS: Principal inclusion criteria were 12 years of age or older and in vivo confocal microscopy with clinical findings consistent with AK. Also included were participants with concurrent bacterial keratitis who were using topical steroids and antiviral and antifungal drugs before randomization. Principal exclusion criteria were concurrent herpes or fungal keratitis and use of antiamebic therapy (AAT). Patients were randomized 1:1 using a computer-generated block size of 4. This was a superiority trial having a predefined noninferiority margin. The sample size of 130 participants gave approximately 80% power to detect 20-percentage point superiority for PHMB 0.08% for the primary outcome of the medical cure rate (MCR; without surgery or change of AAT) within 12 months, cure defined by clinical criteria 90 days after discontinuing anti-inflammatory agents and AAT. A prespecified multivariable analysis adjusted for baseline imbalances in risk factors affecting outcomes. MAIN OUTCOME MEASURES: The main outcome measure was MCR within 12 months, with secondary outcomes including best-corrected visual acuity and treatment failure rates. Safety outcomes included adverse event rates. RESULTS: One hundred thirty-five participants were randomized, providing 127 in the full-analysis subset (61 receiving PHMB 0.02%+ propamidine and 66 receiving PHMB 0.08%) and 134 in the safety analysis subset. The adjusted MCR within 12 months was 86.6% (unadjusted, 88.5%) for PHMB 0.02%+ propamidine and 86.7% (unadjusted, 84.9%) for PHMB 0.08%; the noninferiority requirement for PHMB 0.08% was met (adjusted difference, 0.1 percentage points; lower one-sided 95% confidence limit, -8.3 percentage points). Secondary outcomes were similar for both treatments and were not analyzed statistically: median best-corrected visual acuity of 20/20 and an overall treatment failure rate of 17 of 127 patients (13.4%), of whom 8 of 127 patients (6.3%) required therapeutic keratoplasty. No serious drug-related adverse events occurred. CONCLUSIONS: PHMB 0.08% monotherapy may be as effective (or at worse only 8 percentage points less effective) as dual therapy with PHMB 0.02%+ propamidine (a widely used therapy) with medical cure rates of more than 86%, when used with the trial treatment delivery protocol in populations with AK with similar disease severity. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Topical Nerve Growth Factor (NGF) restores electrophysiological alterations in the Ins2Akita mouse model of diabetic retinopathy.

People suffering from diabetes mellitus commonly have to face diabetic retinopathy (DR), an eye disease characterized by early retinal neurodegeneration and microvascular damage, progressively leading to sight loss. The Ins2Akita (Akita) diabetic mouse presents the characteristics of DR and experimental drugs can be tested on this model to check their efficacy before going to the clinic. Topical administration of Nerve Growth Factor (NGF) has been recently demonstrated to prevent DR in the Akita mouse, reverting the thinning of retinal layers and protecting the retinal ganglion cells (RGCs) from death. In this study, we characterize the effects of topical NGF on neuroretina function, quantified with the electroretinogram (ERG). In particular, we show that NGF can ameliorate RGC conduction in the retina of Akita mice, which correlates with a recovery of retinal nerve fiber plus ganglion cell layer (RNFL-GCL) structure. Overall, our preclinical results highlight that topical administration of NGF could be a promising therapeutic approach for DR, being capable of exerting a beneficial impact on retinal functionality.

Progressive Thinning of Retinal Nerve Fiber Layer/Ganglion Cell Layer (RNFL/GCL) as Biomarker and Pharmacological Target of Diabetic Retinopathy.

Diabetes-driven retinal neurodegeneration has recently been shown to be involved in the initial phases of diabetic retinopathy, raising the possibility of setting up a preventive strategy based on early retinal neuroprotection. To make this possible, it is crucial to identify a biomarker for early retinal neurodegeneration. To this end, in this study, we verified and confirmed that, in the Akita mouse model of diabetes, the thinning of the retinal nerve fiber layer/ganglion cell layer (the RNFL/GCL-the layer that contains the retinal ganglion cells) precedes the death of these same cells, suggesting that this dysfunction is a possible biomarker of retinal neurodegeneration. We then confirmed the validity of this assumption by starting a neuroprotective treatment (based on nerve growth factor eye drops) in concert with the first demonstration of RNFL/GCL thinning. In this way, it was possible not only to avoid the loss of retinal ganglion cells but also to prevent the subsequent development of the microvascular stage of diabetic retinopathy. In conclusion, in the case of diabetes, the thinning of the RNFL/GCL appears to be both a valid biomarker and a pharmacological target of diabetic retinopathy; it precedes the development of vascular dysfunctions and represents the ideal starting point for prevention.

Comparison between Cultivated Oral Mucosa and Ocular Surface Epithelia for COMET Patients Follow-Up.

Total bilateral Limbal Stem Cell Deficiency is a pathologic condition of the ocular surface due to the loss of corneal stem cells. Cultivated oral mucosa epithelial transplantation (COMET) is the only autologous successful treatment for this pathology in clinical application, although abnormal peripheric corneal vascularization often occurs. Properly characterizing the regenerated ocular surface is needed for a reliable follow-up. So far, the univocal identification of transplanted oral mucosa has been challenging. Previously proposed markers were shown to be co-expressed by different ocular surface epithelia in a homeostatic or perturbated environment. In this study, we compared the transcriptome profile of human oral mucosa, limbal and conjunctival cultured holoclones, identifying Paired Like Homeodomain 2 (PITX2) as a new marker that univocally distinguishes the transplanted oral tissue from the other epithelia. We validated PITX2 at RNA and protein levels to investigate 10-year follow-up corneal samples derived from a COMET-treated aniridic patient. Moreover, we found novel angiogenesis-related factors that were differentially expressed in the three epithelia and instrumental in explaining the neovascularization in COMET-treated patients. These results will support the follow-up analysis of patients transplanted with oral mucosa and provide new tools to understand the regeneration mechanism of transplanted corneas.

Immunity and pain in the eye: focus on the ocular surface.

Most ocular diseases are associated with pain. While pain has been generally considered a mere (deleterious) additional symptom, it is now emerging that it is a key modulator of innate/adaptive immunity. Because the cornea receives the highest nerve density of the entire body, it is an ideal site to demonstrate interactions between pain and the immune response. Indeed, most neuropeptides involved in pain generation are also potent regulators of innate and adaptive leukocyte physiology. On the other hand, most inflammatory cells can modulate the generation of ocular pain through release of specific mediators (cytokines, chemokines, growth factors, and lipid mediators). This review will discuss the reciprocal role(s) of ocular surface (and specifically: corneal) pain on the immune response of the eye. Finally, we will discuss the clinical implications of such reciprocal interactions in the context of highly prevalent corneal diseases.

Corneal endothelial cell reduction and increased Neurokinin-1 receptor expression in a graft-versus-host disease preclinical model.

The aim of this work was to assess corneal endothelial morphology in a well-established acute graft-versus-host disease (GVHD) murine model and to quantify the expression of neurokinin-1 receptor (NK1R) in the corneal endothelium during ocular GVHD (oGVHD). Pre-conditioning was performed in BALB/c using myeloablative total body irradiation. Subsequently, allogeneic bone marrow transplantation was performed without (BM) or with mature T cells (BM + T). Corneal transparency was monitored with in vivo biomicroscopy. After sacrifice, corneal thickness and endothelial cell number were measured, and the expression of NK1R was investigated in the corneal endothelium through immunofluorescence and quantified by immunohistochemistry. Mice presenting oGVHD showed a significant reduction in endothelial cell number compared to control animals (p < 0.0001). NK1R expression was significantly increased in oGVHD mice endothelium (p < 0.05). Corneal transparency and thickness were unchanged in all groups. Our results suggest that oGVHD affects the corneal endothelium, inducing a reduction of the cell number, and that this is associated with increased expression of the pro-inflammatory marker NK1R.

SOX2 Is a Univocal Marker for Human Oral Mucosa Epithelium Useful in Post-COMET Patient Characterization.

Total bilateral Limbal Stem Cells Deficiency is a pathologic condition of the ocular surface due to loss or impairment of corneal stem cell function, altering homeostasis of the corneal epithelium. Cultivated Oral Mucosa Epithelial Transplantation (COMET) is the only autologous treatment for this pathology. During the follow-up, a proper characterization of the transplanted oral mucosa on the ocular surface supports understanding the regenerative process. The previously proposed markers for oral mucosa identification (e.g., keratins 3 and 13) are co-expressed by corneal and conjunctival epithelia. Here, we propose a new specific marker to distinguish human oral mucosa from the epithelia of the ocular surface. We compared the transcriptome of holoclones (stem cells) from the human oral mucosa, limbal and conjunctival cultures by microarray assay. High expression of SOX2 identified the oral mucosa vs. cornea and conjunctiva, while PAX6 was highly expressed in corneal and conjunctival epithelia. The transcripts were validated by qPCR, and immunological methods identified the related proteins. Finally, the proposed markers were used to analyze a 10-year follow-up aniridic patient treated by COMET. These findings will support the follow-up analysis of COMET treated patients and help to shed light on the mechanism of corneal repair and regeneration.

Topical neurokinin-1 receptor antagonist Fosaprepitant ameliorates ocular graft-versus-host disease in a preclinical mouse model.

PURPOSE: to assess the effect of topical administration of the Neurokin-1 receptor (NK1R) antagonist Fosaprepitant in a pre-clinical model of ocular Graft-versus-Host disease (GVHD). METHODS: BALB/c mice were pre-conditioned by myeloablative total body irradiation and subjected to allogeneic bone marrow transplantation and mature T cell infusion (BM + T). BM-transplanted mice (BM) were used as controls. Ocular GVHD was specifically assessed by quantifying corneal epithelial damage, tear secretion, blepharitis and phimosis, 3 times/week for 28 days post-transplantation. A group of BM + T mice received Fosaprepitant 10 mg/mL, 6 times/day, topically, from day 7-29 after transplantation. After sacrifice, the expression of NK1R, CD45, CD3, and CXCL10 was quantified in the cornea, conjunctiva, and lacrimal gland by immunohistochemistry. RESULTS: BM + T mice developed corneal epithelial damage (day 0-29, p < 0.001), blepharitis (day 0-29, p < 0.001), and phimosis (day 0-29, p < 0.01), and experienced decreased tear secretion (day 21, p < 0.01) compared to controls. NK1R was found upregulated in corneal epithelium (p < 0.01) and lacrimal gland (p < 0.01) of BM + T mice. Fosaprepitant administration significantly reduced corneal epithelial damage (p < 0.05), CD45+ (p < 0.05) and CD3+ (p < 0.01) immune cell infiltration in the cornea and conjunctiva (p < 0.001 and p < 0.001, respectively). In addition, Fosaprepitant reduced the expression of CXCL10 in the cornea (p < 0.05) and in the lacrimal gland (p < 0.05). CONCLUSIONS: Our results suggest that NK1R represents a novel druggable pathway for the therapy of ocular GVHD.

Two-step keratoplasty for deep vascularized corneal opacity with severe peripheral thinning following Acanthamoeba keratitis.

PURPOSE: In cases of corneal opacity with vascularization and peripheral thinning, traditional keratoplasty techniques have several risks and drawbacks. We report the results of a two-step surgical strategy consisting in performing a large diameter tectonic lamellar keratoplasty (TLK) to restore appropriate corneal thickness and an avascular recipient bed, followed by central optical PK within the lamellar graft at a later date. METHODS: This single-institution study analyzes the results of 7 eyes of 7 patients who received PK after large diameter TLK. All patients were affected by deep post-infectious corneal opacity with persistent stromal vascularization and peripheral thinning. The main outcomes measured were graft survival, visual acuity, refraction, and endothelial cell density. RESULTS: TLK was performed in all cases with 10/10.1-mm diameters. After a mean interval of 14 months, central PK was performed with a median host-graft diameter of 7.75/8.25 mm. Mean follow-up after PK was 52 months. At last follow-up, 6/7 (86%) grafts were clear. Endothelial rejection occurred in 5/7 (71%) eyes, with one patient having multiple episodes and subsequent graft failure. At 2 years, all patients had a visual acuity ≥ 20/40, with an average refractive astigmatism of 3.75 diopters. CONCLUSION: Optical PK within a previous TLK is a safe and efficient technique for treating deep corneal opacity associated with extensive vascularization and peripheral thinning. Extended follow-up period is necessary to assess endothelial cell loss and long-term efficacy of the procedure.

NGF Eye Administration Recovers the TrkB and Glutamate/GABA Marker Deficit in the Adult Visual Cortex Following Optic Nerve Crush.

Eye-drop recombinant human nerve growth factor (ed-rhNGF) has proved to recover the retina and optic nerve damage in animal models, including the unilateral optic nerve crush (ONC), and to improve visual acuity in humans. These data, associated with evidence that ed-rhNGF stimulates the brain derived neurotrophic factor (BDNF) in retina and cortex, suggests that NGF might exert retino-fugal effects by affecting BDNF and its receptor TrkB. To address these questions, their expression and relationship with the GABAergic and glutamatergic transmission markers, GAD65 and GAD67, vesicular inhibitory amino acid transporter (VGAT), and vesicular glutamate transporters 1 and 2 (VGLUT-1 and VGLUT-2) were investigated in adult ONC rats contralateral and ipsilateral visual cortex (VCx). Ed-rhNGF recovers the ONC-induced alteration of GABAergic and glutamatergic markers in contralateral VCx, induces an upregulation of TrkB, which is positively correlated with BDNF precursor (proBDNF) decrease in both VCx sides, and strongly enhances TrkB+ cell soma and neuronal endings surrounded by GAD65 immuno-reactive afferents. These findings contribute to enlarging the knowledge on the mechanism of actions and cellular targets of exogenously administrated NGF, and suggest that ed-rhNGF might act by potentiating the activity-dependent TrkB expression in GAD+ cells in VCx following retina damage and/or ONC.

Phase II Randomized, Double-Masked, Vehicle-Controlled Trial of Recombinant Human Nerve Growth Factor for Neurotrophic Keratitis.

PURPOSE: To evaluate the safety and efficacy of topical recombinant human nerve growth factor (rhNGF) for treating moderate-to-severe neurotrophic keratitis (NK), a rare degenerative corneal disease resulting from impaired corneal innervation. DESIGN: Phase II multicenter, randomized, double-masked, vehicle-controlled trial. PARTICIPANTS: Patients with stage 2 (moderate) or stage 3 (severe) NK in 1 eye. METHODS: The REPARO phase II study assessed safety and efficacy in 156 patients randomized 1:1:1 to rhNGF 10 µg/ml, 20 µg/ml, or vehicle. Treatment was administered 6 drops per day for 8 weeks. Patients then entered a 48- or 56-week follow-up period. Safety was assessed in all patients who received study treatment, whereas efficacy was by intention to treat. MAIN OUTCOME MEASURES: Corneal healing (defined as <0.5-mm maximum diameter of fluorescein staining in the lesion area) was assessed by masked central readers at week 4 (primary efficacy end point) and week 8 (key secondary end point) of controlled treatment. Corneal healing was reassessed post hoc by masked central readers using a more conservative measure (0-mm staining in the lesion area and no other persistent staining). RESULTS: At week 4 (primary end point), 19.6% of vehicle-treated patients achieved corneal healing (<0.5-mm lesion staining) versus 54.9% receiving rhNGF 10 µg/ml (+35.3%; 97.06% confidence interval [CI], 15.88-54.71; P < 0.001) and 58.0% receiving rhNGF 20 µg/ml (+38.4%; 97.06% CI, 18.96-57.83; P < 0.001). At week 8 (key secondary end point), 43.1% of vehicle-treated patients achieved less than 0.5-mm lesion staining versus 74.5% receiving rhNGF 10 µg/ml (+31.4%; 97.06% CI, 11.25-51.49; P = 0.001) and 74.0% receiving rhNGF 20 µg/ml (+30.9%; 97.06% CI, 10.60-51.13; P = 0.002). Post hoc analysis of corneal healing by the more conservative measure (0-mm lesion staining and no other persistent staining) maintained statistically significant differences between rhNGF and vehicle at weeks 4 and 8. More than 96% of patients who healed after controlled rhNGF treatment remained recurrence free during follow-up. Treatment with rhNGF was well tolerated; adverse effects were mostly local, mild, and transient. CONCLUSIONS: Topical rhNGF is safe and more effective than vehicle in promoting healing of moderate-to-severe NK.

Cultivated limbal epithelial transplantation.

PURPOSE OF REVIEW: To provide an updated literature review on the status of cultivated limbal (corneal) epithelial transplantation. Cultivated limbal stem-cell transplantation recently received regulatory approval. We provide a comprehensive overview of recent developments in the field. RECENT FINDINGS: The current article reviews and highlights recent developments in the field of cultivated limbal stem-cell transplantation as retrieved from a literature search for the last year. SUMMARY: The implications of clinical/research findings in terms of transplanted cell source and cultivation methods in limbal stem-cell transplantation are reviewed.

Time-Dependent Nerve Growth Factor Signaling Changes in the Rat Retina During Optic Nerve Crush-Induced Degeneration of Retinal Ganglion Cells.

Nerve growth factor (NGF) is suggested to be neuroprotective after nerve injury; however, retinal ganglion cells (RGC) degenerate following optic-nerve crush (ONC), even in the presence of increased levels of endogenous NGF. To further investigate this apparently paradoxical condition, a time-course study was performed to evaluate the effects of unilateral ONC on NGF expression and signaling in the adult retina. Visually evoked potential and immunofluorescence staining were used to assess axonal damage and RGC loss. The levels of NGF, proNGF, p75NTR, TrkA and GFAP and the activation of several intracellular pathways were analyzed at 1, 3, 7 and 14 days after crush (dac) by ELISA/Western Blot and PathScan intracellular signaling array. The progressive RGC loss and nerve impairment featured an early and sustained activation of apoptotic pathways; and GFAP and p75NTR enhancement. In contrast, ONC-induced reduction of TrkA, and increased proNGF were observed only at 7 and 14 dac. We propose that proNGF and p75NTR contribute to exacerbate retinal degeneration by further stimulating apoptosis during the second week after injury, and thus hamper the neuroprotective effect of the endogenous NGF. These findings might aid in identifying effective treatment windows for NGF-based strategies to counteract retinal and/or optic-nerve degeneration.

Central Corneal Thickness Reproducibility among Ten Different Instruments.

PURPOSE: To assess agreement between one ultrasonic (US) and nine optical instruments for the measurement of central corneal thickness (CCT), and to evaluate intra- and inter-operator reproducibility. METHODS: In this observational cross-sectional study, two masked operators measured CCT thickness twice in 28 healthy eyes. We used seven spectral-domain optical coherence tomography (SD-OCT) devices, one time-domain OCT, one Scheimpflug camera, and one US-based instrument. Inter- and intra-operator reproducibility was evaluated by intraclass correlation coefficient (ICC), coefficient of variation (CV), and Bland-Altman test analysis. Instrument-to-instrument reproducibility was determined by ANOVA for repeated measurements. We also tested how the devices disagreed regarding systemic bias and random error using a structural equation model. RESULTS: Mean CCT of all instruments ranged from 536 ± 42 µm to 577 ± 40 µm. An instrument-to-instrument correlation test showed high values among the 10 investigated devices (correlation coefficient range 0.852-0.995; p values <0.0001 in all cases). The highest correlation coefficient values were registered between 3D OCT-2000 Topcon-Spectral OCT/SLO Opko (0.995) and Cirrus HD-OCT Zeiss-RS-3000 Nidek (0.995), whereas the lowest were seen between SS-1000 CASIA and Spectral OCT/SLO Opko (0.852). ICC and CV showed excellent inter- and intra-operator reproducibility for all optic-based devices, except for the US-based device. Bland-Altman analysis demonstrated low mean biases between operators. CONCLUSIONS: Despite highlighting good intra- and inter-operator reproducibility, we found that a scale bias between instruments might interfere with thorough CCT monitoring. We suggest that optimal monitoring is achieved with the same operator and the same device.

Concise review: hurdles in a successful example of limbal stem cell-based regenerative medicine.

Recent breakthroughs in regenerative medicine have generated enthusiasm and many efforts to explore new therapeutic potentials of both somatic and pluripotent stem cells. About 30 years passed since a discovery of a method of producing a great number of human epidermal keratinocytes by cultivation from a small skin biopsy, many possibilities are now envisaged for therapeutic application of different cultured cell types. The importance of stem cell content was proven for many tissues or organs in different pathologies. Ocular burns cause depletion of limbal stem cells, which lead to corneal opacification and visual loss. Most of available treatments are palliative and focused on the relief of the devastating clinical picture. This review is focused on recent developments in cell-based therapy of limbal stem cell deficiency. All findings can provide support for improvement and standardization of the cure for this disabling disease.

Tumor necrosis factor-α inhibitors as a treatment of corneal hemangiogenesis and lymphangiogenesis.

The cornea is normally devoid of blood and lymphatic vessels; however, a number of infectious/inflammatory diseases can induce corneal neovascularization (CNV). Tumor necrosis factor (TNF)-α, a well known pro-inflammatory cytokine, acts on the vascular endothelium by promoting vasodilatation, edema, and leukocyte recruitment, which are all commonly associated with the development of CNV. Corneal neovascularization is the second cause of blindness worldwide; hence, pharmacological TNF-α inhibition might represent an attractive therapeutic option. Although none of the existing TNF-α antagonists has been registered as a CNV inhibitor, three of them (etanercept, adalimumab, and infliximab) have been proposed to control ocular inflammation. More specifically, it has been demonstrated that infliximab is also effective in reducing hemangiogenesis and lymphangiogenesis in different animal models of CNV. In this article, we review the role of TNF-α on the ocular surface and, in particular, its specific role in the process of CNV. Moreover, we review existing literature and speculate on the potential role of TNF-α inhibitors in the treatment of CNV.

Alkali burn versus suture-induced corneal neovascularization in C57BL/6 mice: an overview of two common animal models of corneal neovascularization.

The purpose of the present study was to quantify and compare corneal hem- and lymphangiogenesis between alkali burn and suture-induced corneal neovascularization (CNV) in two commonly used mouse strains. A retrospective analysis was performed on C57BL/6 and FVB neovascularized corneas. CNV was induced by surface caustication with NaOH or intrastromal placement of three 10.0 nylon sutures. Hemangiogenesis and lymphangiogenesis extent was calculated on whole mounted corneas by CD31 and LYVE1 immunofluorescence analysis. Blood vessel growth was similar between alkali burn and suture-induced CNV in C57BL/6 mice, and between C57BL/6 and FVB sutured strains. On the contrary, corneal lymphangiogenesis was more pronounced in the C57BL/6 sutured mice versus the alkali burn group, and in the FVB strain versus both C57BL/6 models. These results indicate that significant differences occur in lymphangiogenesis, but not hemangiogenesis, in the alkali burn and suture-induced models in C57BL/6 mice. Furthermore, lymphangiogenesis is more pronounced in the albino (FVB) strain after suture placement. We suggest that the suture model has a number of advantages and may be preferentially used to study corneal lymphangiogenesis.

Unusual presentation of ocular surface squamous neoplasia in a young healthy patient: A case report.

PURPOSE: To report an unusual case of ocular surface squamous neoplasia (OSSN) associated with human papilloma virus (HPV)-16 infection with an atypical morphology in a young otherwise healthy patient. CASE DESCRIPTION: A 17 year-old healthy male was referred to our department for evaluation of a corneal infiltrate with anterior stromal neovascularization in the right eye. One year before, the patient underwent an excision of a corneo-conjunctival lesion that was located inferiorly in the same eye. Histopathological analysis had shown moderate and severe dysplasia of the conjunctival epithelium and resulted positive for HPV-16. We performed a diagnostic incisional biopsy of the limbal conjunctiva and of the corneal epithelium for histological examination and molecular testing for HPV and Chlamydia by using polymerase chain reaction (PCR). Histopathologic evaluation demonstrated low-grade dysplasia of conjunctiva. PCR testing of the corneal epithelium was positive for HPV-16, similarly to the first biopsy performed by another centre. The patient was successfully treated with topical interferon alfa-2b (1,000,000 IU/ml) for a total of six months. After the treatment, the corneal infiltrate improved dramatically with regression of neovascularization and improvement of corneal transparency and vision. DISCUSSION: The present report described an atypical presentation of HPV-related OSSN due to its unusual morphology, young age of onset and absence of associated comorbidity. CONCLUSION: Conservative treatment with topical interferon-alpha 2b could be used to treat successfully HPV-16 positive OSSN, with no corneal irregularity or potential loss of vision compared to surgical excision.

Limbal stem-cell therapy and long-term corneal regeneration.

BACKGROUND: Corneal renewal and repair are mediated by stem cells of the limbus, the narrow zone between the cornea and the bulbar conjunctiva. Ocular burns may destroy the limbus, causing limbal stem-cell deficiency. We investigated the long-term clinical results of cell therapy in patients with burn-related corneal destruction associated with limbal stem-cell deficiency, a highly disabling ocular disease. METHODS: We used autologous limbal stem cells cultivated on fibrin to treat 112 patients with corneal damage, most of whom had burn-dependent limbal stem-cell deficiency. Clinical results were assessed by means of Kaplan-Meier, Kruskal-Wallis, and univariate and multivariate logistic-regression analyses. We also assessed the clinical outcome according to the percentage of holoclone-forming stem cells, detected as cells that stain intensely (p63-bright cells) in the cultures. RESULTS: Permanent restoration of a transparent, renewing corneal epithelium was attained in 76.6% of eyes. The failures occurred within the first year. Restored eyes remained stable over time, with up to 10 years of follow-up (mean, 2.91+/-1.99; median, 1.93). In post hoc analyses, success--that is, the generation of normal epithelium on donor stroma--was associated with the percentage of p63-bright holoclone-forming stem cells in culture. Cultures in which p63-bright cells constituted more than 3% of the total number of clonogenic cells were associated with successful transplantation in 78% of patients. In contrast, cultures in which such cells made up 3% or less of the total number of cells were associated with successful transplantation in only 11% of patients. Graft failure was also associated with the type of initial ocular damage and postoperative complications. CONCLUSIONS: Cultures of limbal stem cells represent a source of cells for transplantation in the treatment of destruction of the human cornea due to burns.