Giulio Ferrari

Targeting amyloid-β in glaucoma treatment

The development of the devastating neurodegenerative condition, Alzheimers disease, is strongly associated with amyloid-β (Aβ) deposition, neuronal apoptosis, and cell loss. Here, we provide evidence that implicates these same mechanisms in the retinal disease glaucoma, a major cause of irreversible blindness worldwide, previously associated simply with the effects of intraocular pressure. We show that Aβ colocalizes with apoptotic retinal ganglion cells (RGC) in experimental glaucoma and induces significant RGC apoptosis in vivo in a dose- and time-dependent manner. We demonstrate that targeting different components of the Aβ formation and aggregation pathway can effectively reduce glaucomatous RGC apoptosis in vivo, and finally, that combining treatments (triple therapy) is more effective than monotherapy. Our work suggests that targeting the Aβ pathway provides a therapeutic avenue in glaucoma management. Furthermore, our work demonstrates that the combination of agents affecting multiple stages in the Aβ pathway may be the most effective strategy in Aβ-related diseases.

Dependence of Corneal Stem/Progenitor Cells on Ocular Surface Innervation

PURPOSE Neurotrophic keratopathy (NK) is a corneal degeneration associated with corneal nerve dysfunction. It can cause corneal epithelial defects, stromal thinning, and perforation. However, it is not clear if and to which extent epithelial stem cells are affected in NK. The purpose of this study was to identify the relationship between corneolimbal epithelial progenitor/stem cells and sensory nerves using a denervated mouse model of NK. METHODS NK was induced in mice by electrocoagulation of the ophthalmic branch of the trigeminal nerve. The absence of corneal nerves was confirmed with β-III tubulin immunostaining and blink reflex test after 7 days. ATP-binding cassette subfamily G member 2 (ABCG2), p63, and hairy enhancer of split 1 (Hes1) were chosen as corneolimbal stem/progenitor cell markers and assessed in denervated mice versus controls by immunofluorescent microscopy and real-time PCR. In addition, corneolimbal stem/progenitor cells were detected as side population cells using flow cytometry, and colony-forming efficiency assay was performed to assess their function. RESULTS ABCG2, p63, and Hes1 immunostaining were significantly decreased in denervated eyes after 7 days. Similarly, the expression levels of ABCG2, p63, K15, Hes1, and N-cadherin transcripts were also significantly decreased in denervated eyes. Stem/progenitor cells measured as side population from NK mice were decreased by approximately 75% compared with normals. In addition, the authors found a significant (P = 0.038) reduction in colony-forming efficiency of stem/progenitor cells harvested from denervated eyes. CONCLUSIONS Corneolimbal stem/progenitor cells are significantly reduced after depletion of sensory nerves. The data suggest a critical role of innervation in maintaining stem cells and/or the stem cell niche.

Topical interleukin 1 receptor antagonist for treatment of dry eye disease: a randomized clinical trial.

IMPORTANCE The immunopathogenic mechanisms of dry eye disease (DED), one of the most common ophthalmic conditions, is incompletely understood. Data from this prospective, double-masked, randomized trial demonstrate that targeting interleukin 1 (IL-1) by topical application of an IL-1 antagonist is efficacious in significantly reducing DED-related patient symptoms and corneal epitheliopathy. OBJECTIVE To evaluate the safety and efficacy of treatment with the topical IL-1 receptor antagonist anakinra (Kineret; Amgen Inc) in patients having DED associated with meibomian gland dysfunction. DESIGN AND SETTING Prospective phase 1/2, randomized, double-masked, vehicle-controlled clinical trial. PARTICIPANTS Seventy-five patients with refractory DED. INTERVENTIONS Participants were randomized to receive treatment with topical anakinra, 2.5% (n = 30), anakinra, 5% (n = 15), or vehicle (1% carboxymethylcellulose) (n = 30) 3 times daily for 12 weeks. MAIN OUTCOMES AND MEASURES Primary outcomes were corneal fluorescein staining (CFS), complete bilateral CFS clearance, dry eye-related symptoms as measured by the Ocular Surface Disease Index, tear film breakup time, and meibomian gland secretion quality. RESULTS Topical anakinra was well tolerated compared with vehicle, with no reports of serious adverse reactions attributable to the therapy. After 12 weeks of therapy, participants treated with anakinra, 2.5%, achieved a 46% reduction in their mean CFS score (P = .12 compared with vehicle and P < .001 compared with baseline); participants treated with anakinra, 5%, achieved a 17% reduction in their mean CFS score (P = .88 compared with vehicle and P = .33 compared with baseline); and patients treated with vehicle achieved a 19% reduction in their mean CFS score (P = .11). Complete bilateral CFS clearance was noted in 8 of 28 patients (29%) treated with anakinra, 2.5%, vs in 2 of 29 patients (7%) treated with vehicle (P = .03). By week 12, treatment with anakinra, 2.5%, and treatment with anakinra, 5%, led to significant reductions in symptoms of 30% and 35%, respectively (P = .02 and P = .01, respectively, compared with vehicle); treatment with vehicle led to a 5% reduction in symptoms. CONCLUSIONS AND RELEVANCE Treatment with topical anakinra, 2.5%, for 12 weeks was safe and significantly reduced symptoms and corneal epitheliopathy in patients with DED. These data suggest that the use of an IL-1 antagonist may have a role as a novel therapeutic option for patients with DED. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00681109.

Safety and efficacy of topical infliximab in a mouse model of ocular surface scarring.

PURPOSE To evaluate the safety/efficacy of topical infliximab, an anti-TNF-α monoclonal antibody, in a mouse model of ocular surface scarring. METHODS Twenty alkali burn mice were treated with infliximab (10 mg/mL) topically 6 times a day, while 20 alkali burn mice received saline for 7 days. Corneal opacity, epithelial wound healing, and ocular phimosis were examined at the slit-lamp. Tear production was quantified with phenol red thread test. Immunofluorescence for infliximab penetration, TNF-α localization, CD45+ cell infiltration, PAS, and Massons trichrome staining were evaluated on ocular globes and eyelids. TNF-α and IL-1β expression levels were measured on treated murine corneas and eyelids. Finally, quantification of corneal CD31+ blood vessels and LYVE1+ lymphatic vessels were evaluated on 10 additional alkali burn mice receiving either infliximab or saline, after 14 days. RESULTS Topical infliximab penetrated the cornea and the conjunctiva and was not toxic (negative fluorescein stain). Its molecular target, TNF-α, was detected in the cornea after injury. Infliximab significantly reduced corneal perforation, opacity index, phimosis, leukocyte infiltration, and fibrosis in the eyelids. It also significantly prevented goblet cell infiltration in epithelial cornea and loss in the conjunctiva (P < 0.05), improved tear secretion and epithelial healing (P < 0.05). Finally, it significantly reduced both corneal hem- (P < 0.05) and lymphangiogenesis (P < 0.01). CONCLUSIONS Infliximab penetrates the cornea and is safe to the ocular surface in an animal model of ocular surface scarring. We suggest that topical application of infliximab may be a useful treatment in ocular caustications.

Short-term topical bevacizumab in the treatment of stable corneal neovascularization.

PURPOSE To evaluate the safety and efficacy of topical bevacizumab in the treatment of corneal neovascularization. DESIGN Prospective, nonrandomized, interventional case series. METHODS setting: Institutional, multicenter clinical trial. study population: Twenty eyes from 20 patients with stable corneal neovascularization. intervention procedures: Patients were treated with topical 1.0% bevacizumab for 3 weeks and were monitored for a total of 24 weeks. main outcome measures: Primary outcome measures included: neovascular area, defined as the area of the corneal vessels themselves; vessel caliber, defined as the mean corneal vessel diameter; and invasion area, defined as the fraction of the total cornea into which the vessels extended. The occurrence of ocular and systemic adverse events was monitored closely. RESULTS As compared with the baseline visit, patients exhibited a statistically significant improvement in neovascular area by week 6 (P = .007) and in vessel caliber by week 12 (P = .006). At the final visit, neovascular area, vessel caliber, and invasion area were reduced by 47.5%, 36.2%, and 20%, respectively. The decreases in neovascular area and vessel caliber were statistically significant (P < .001 and P = .003, respectively); however, the reduction in invasion area did not reach statistical significance (P = .06). There were no significant changes in the secondary outcomes, and there were no adverse events. CONCLUSIONS Short-term topical bevacizumab treatment reduced the extent of stable corneal neovascularization as measured by neovascular area and vessel caliber with no associated adverse events. Interestingly, the degree of treatment efficacy was inversely proportional to the baseline invasion area.

A Novel Mouse Model for Neurotrophic Keratopathy: Trigeminal Nerve Stereotactic Electrolysis through the Brain

PURPOSE To develop a mouse model of neurotrophic keratopathy by approaching the trigeminal nerve through the brain and to evaluate changes in corneal cell apoptosis and proliferation. METHODS Six- to 8-week-old male C57BL/6 mice underwent trigeminal stereotactic electrolysis (TSE) to destroy the ophthalmic branch of the trigeminal nerve. Clinical follow-up using biomicroscopy of the cornea was performed at days 2, 4, 5, and 7. To confirm the effectiveness of the procedure, we examined the gross nerve pathology, blink reflex, and immunohistochemistry of the corneal nerves. TUNEL-positive apoptotic and Ki-67-positive proliferating corneal cells were evaluated to detect changes from the contralateral normal eye. RESULTS TSE was confirmed by gross histology of the trigeminal nerve and was considered effective if the corneal blink reflex was completely abolished. TSE totally abolished the blink reflex in 70% of mice and significantly reduced it in the remaining 30%. Animals with absent blink reflex were used for subsequent experiments. In these mice, a progressive corneal degeneration developed, with thinning of the corneal epithelium and eventually perforation after 7 days. In all mice, 48 hours after TSE, corneal nerves were not recognizable histologically. Seven days after TSE, an increase in cellular apoptosis in all the corneal layers and a reduction in proliferation in basal epithelial cells were detected consistently in all mice. CONCLUSIONS TSE was able, in most cases, to induce a disease state that reflected clinical neurotrophic keratitis without damaging the periocular structures. Moreover, corneal denervation led to increased apoptosis and reduced proliferation of epithelial cells, formally implicating intact nerve function in regulating epithelial survival and turnover.

Topical Ranibizumab as a Treatment of Corneal Neovascularization

Purpose: To examine the effect of topical ranibizumab on clinically stable corneal neovascularization (NV). Methods: This was a prospective, open-label, monocentric, uncontrolled noncomparative study. Ten eyes of 9 patients with corneal NV received topical ranibizumab (1%) 4 times a day for 3 weeks with a follow-up period of 16 weeks. The main corneal NV outcome measures were: neovascular area, the area occupied by the corneal neovessels; vessel caliber (VC), the mean diameter of the corneal neovessels; and invasion area (IA), the fraction of the total cornea area covered by the vessels. This study was conducted at the Massachusetts Eye and Ear Infirmary, Boston, MA. Results: Statistically significant decreases in neovascular area (55.3%, P < 0.001), which lasted through 16 weeks, and VC (59%, P < 0.001), which continued to improve up to week 16, were observed after treatment. No significant decrease was observed in IA (12.3%, P = 0.49). There was no statistically significant change in visual acuity or intraocular pressure. No adverse events ascribed to the treatment were noted. Conclusions: Topical application of ranibizumab is effective in reducing the severity of corneal NV in the context of established corneal NV, mostly through decrease in VC rather than IA.

In-vitro permeation of bevacizumab through human sclera: effect of iontophoresis application

Objectives  Bevacizumab (Avastin) is a recombinant humanized monoclonal antibody used in ophthalmology (off‐label) for the treatment of neovascularization in diseases such as diabetic retinopathy and age‐related macular degeneration (wet form). Bevacizumab is currently administrated by repeated intravitreal injection, which can cause severe complications; a non‐invasive delivery route is therefore desirable. The passive permeation of bevacizumab through isolated human sclera was evaluated and the iontophoretic technique was explored as a method to enhance its transscleral transport in vitro.

Non-length-dependent small fibre neuropathy. Confocal microscopy study of the corneal innervation

Background It has been recently observed that small fibre neuropathy (SFN) may present as distal symmetrical polyneuropathy and with atypical non-length-dependent pattern. Objective To describe a small series of patients with non-length-dependent SFN, investigating corneal innervation with corneal confocal microscopy (CCM). Methods Evaluation of the corneal nerve fibre density using CCM in six women with non-length-dependent SFN. The patients were characterised by sensory disturbance involving proximal regions of the limbs, face and trunks, and the diagnosis was confirmed by the findings of decreased intraepidermal nerve fibre density on skin biopsy. Results Six women, aged 35–64, had non-length-dependent SFN, related to Crohn disease, impaired glucose tolerance and Sjögrens syndrome, or idiopathic (three cases). In all patients, CCM demonstrated decreased corneal nerve fibre density (12.5–23.4/mm2; normal, >30.6/mm2). Conclusion Non-length-dependent SFN may represent an intriguing diagnostic problem because of its puzzling presentation and the need for special investigations for its confirmation. In this perspective, CCM may provide a useful, non-invasive tool to complement the diagnostic workup.

Nerves and Neovessels Inhibit Each Other in the Cornea

PURPOSE To evaluate the regulatory cross-talk of the vascular and neural networks in the cornea. METHODS b-FGF micropellets (80 ng) were implanted in the temporal side of the cornea of healthy C57Bl/6 mice. On day 7, blood vessels (hemangiogenesis) and nerves were observed by immunofluorescence staining of corneal flat mounts. The next group of mice underwent either trigeminal stereotactic electrolysis (TSE), or sham operation, to ablate the ophthalmic branch of the trigeminal nerve. Blood vessel growth was detected by immunohistochemistry for PECAM-1 (CD31) following surgery. In another set of mice following TSE or sham operation, corneas were harvested for ELISA (VEGFR3 and pigment epithelium-derived factor [PEDF]) and for quantitative RT-PCR (VEGFR3, PEDF, and CD45). PEDF, VEGFR3, beta-3 tubulin, CD45, CD11b, and F4/80 expression in the cornea were evaluated using immunostaining. RESULTS No nerves were detected in the areas subject to corneal neovascularization, whereas they persisted in the areas that were neovessel-free. Conversely, 7 days after denervation, significant angiogenesis was detected in the cornea, and this was associated with a significant decrease in VEGFR3 (57.5% reduction, P = 0.001) and PEDF protein expression (64% reduction, P < 0.001). Immunostaining also showed reduced expression of VEGFR3 in the corneal epithelial layer. Finally, an inflammatory cell infiltrate, including macrophages, was observed. CONCLUSION Our data suggest that sensory nerves and neovessels inhibit each other in the cornea. When vessel growth is stimulated, nerves disappear and, conversely, denervation induces angiogenesis. This phenomenon, here described in the eye, may have far-reaching implications in understanding angiogenesis.