Recombinant Human Nerve Growth Factor Research Articles

Effect of Topical Recombinant Human Nerve Growth Factor on Corneal Epithelial Regeneration in Refractory Epithelial Keratopathy

ABSTRACT Purpose To report the effect of topical application of recombinant human nerve growth factor (rhNGF) eye drops on corneal epithelial regeneration in patients with refractory epitheliopathy. Methods A retrospective chart review was conducted on patients treated with topical rhNGF for refractory epithelial keratopathy due to stage I neurotrophic keratitis (NK). Data regarding demographics and ocular/systemic past medical history was extracted from patient charts. Visual acuity and corneal staining scores were recorded at baseline and subsequent follow-up visits at 8 weeks and 3 months. Measurements from the worse eye were used to compare before and after treatment values. Results We identified 14 patients (median age 68 years, 21% male) who received rhNGF treatment for refractory epithelial keratopathy. After an 8-week treatment with topical rhNGF, the median corneal staining score in the worse eye improved from 4 to 1 (p = 0.001). All patients showed at least one-grade improvement in corneal staining at 8 weeks, with sustained effect in seven patients at 3 months. A better response was observed in eyes with post-radiation epithelial keratopathy, LASIK, and Sjogren’s disease. Those with chronic use of other topical treatments and uncontrolled diabetes mellitus demonstrated incomplete responses. Eight patients reported mild-to-moderate ocular discomfort from drop application that fully resolved after completion of treatment. Conclusions Topical rhNGF was effective and safe for refractory epithelial keratopathy in our small cohort, but sustained effects were seen only in certain etiologies for up to 3 months. Further studies are needed for optimal dosing and duration based on underlying causes.

Prevention and Treatment of Persistent Epithelial Defects After Common Refractive Surgery Procedures.

To discuss the prevention and treatment of persistent epithelial defects after the most common refractive surgeries-photorefractive keratectomy, laser in situ keratomileusis, or small incision lenticule extraction. PubMed was used to search the medical literature. Persistent epithelial defects are infrequent after photorefractive keratectomy, laser in situ keratomileusis, or small incision lenticule extraction. In the authors' opinion, any persistent epithelial defect present at 1 week or beyond after surgery should be treated aggressively with a properly fit bandage contact lens, lubrication with non-preserved artificial tears, and treatment of any eyelid abnormalities, including nocturnal lagophthalmos. Consideration should be given for presumptive treatment for herpes simplex virus or varicella zoster virus infection. If the persistent epithelial defect does not close within 2 weeks, then other measures should be considered, such as autologous serum drops, topical losartan, amniotic membranes, and topical human recombinant nerve growth factor to limit corneal scarring fibrosis and microbial infection. Persistent epithelial defects are among the most feared complications of refractive surgery. Timely and aggressive treatment should be instituted to close the epithelium prior to the development of scarring fibrosis and/or microbial corneal infection. [J Refract Surg. 2024;40(2):e117-e124.].

Medical and surgical management of neurotrophic keratopathy

Neurotrophic Keratopathy (NK) is not a specific disease entity but a consequence of several conditions with varied aetiopathogenesis, of which a loss or reduction in corneal sensitivity is the hallmark. NK is clinically graded as Mild (stage1), Moderate (stage 2) and Severe (stage 3). The grading helps in understanding severity and planning treatment. Management can be considered in two parts. The first is the management of the underlying condition when active, for example herpes virus keratitis, bacterial ulcers and immune mediated ulcerative keratitis; and the second part, which deals with treatment of the non‐healing epithelial defect, stromal melting with or without vascularization and perforation that remains due to epithelial, stromal and corneal nerve pathology.Management of mild and moderate NK begins with the identification and elimination of any obvious underlying cause such as neuroleptic, antipsychotic, antihistamine and other systemic medications, preservatives in long term topical medications; and treatment of concurrent ocular surface infection. Tear substitutes and anti‐inflammatory agents both steroids and specific immunosuppressors like cyclosporin and lifitegrast should be used early. Antibiotics can be used prophylactically or to treat subclinical or overt infection. Medication with preservatives should be avoided. Prevention of progression to severe (stage 3) NK can be achieved with antiproteases such as citrate, tetracyclines and macrolides. Substrate re‐generating agents like Cacicol and promoters of epithelial regeneration like co‐enzyme Q10 target aspects of the underlying pathology. The introduction of recombinant human nerve growth factor (rh)NGF (Cenegermin/Oxervate) has provided specific therapy that addresses the basic defect related to corneal nerves. Insulin drops are proving to be useful and amniotic membrane extracts/amniotic fluid has also been tried. Autologous and pooled allo serum or plasma drops, which provide a variety of known and unknown factors have also proved useful but may at times aggravate the condition. Usually a combination of two or more of the above are required but rhNGF and insulin hold considerable promise for long term remission.Medical treatment is often augmented with non‐surgical interventions such as bandage contact lens, padding, punctal plugs, botulinum toxin, frost suture and glue. These are primarily designed to deal with exposure, dry eyes and reduce the abrasive effect of lid blinks, to promote healing. Useful surgical procedures include tarsorrhaphy, amniotic and conjunctival grafts, penetrating and lamellar keratoplasty and limbal stem cell transplants. Surgical interventions are designed to augment effects of the non‐surgical interventions, reduce scarring, deal with complications and restore sight. A key principle is that wound healing after any form of surgery or transplant, is poor if the corneal sensations remain impaired or absent.

Enhanced neuroprotective activity of ophthalmic delivered nerve growth factor conjugated with cell penetrating peptide against optic nerve injury

Nerve growth factor is a well characterized neurotrophic factor that play a critical role in the survival, growth, and differentiation of neurons both in central and peripheral nervous system. However, it is difficult for the conventional exogenous nerve growth factor administration delivery to the central nervous system due to the biological barrier in human bodies. Here, we validated a series of cell penetrating peptides and found that L-PenetraMax significantly enhanced the efficiency of recombinant human nerve growth factor entry into the rat retina. In the optic nerve crush mice model, eye drop administration of recombinant human nerve growth factor alone promoted retinal ganglion cell survival and axon regeneration at high dose, while the combination of recombinant human nerve growth factor with L-PenetraMax significantly enhanced the neuroprotective efficacy at lower dose, thus potentially enhancing the availability of recombinant human nerve growth factor eye drops in patients with optic neuropathy. This study provides the evidence that the noncovalent coadministration of recombinant human nerve growth factor with L-PenetraMax could be a potent strategy for the non-invasive and sustained ocular delivery of therapeutic proteins for improving the optic nerve injury.

A New Treatment for Recalcitrant Neurotrophic Keratopathy of Ocular Graft-Versus-Host Disease with Virus Infection.

Neurotrophic keratopathy (NK) is a rare degenerative ocular disease that can be difficult to treat. There were no effective resolutive treatments for severe NK caused by ocular graft-versus-host disease (oGVHD) along with virus infection. To address this question, we designed a prospective cohort study to evaluate the efficacy and safety of topical recombinant human nerve growth factor (rhNGF) in patients with recalcitrant NK of oGVHD and viral infection. This prospective cohort study enrolled patients with recalcitrant NK diagnosed with oGVHD and treated with rhNGF. Clinical evaluations included the range of epithelial defects, best corrected visual acuity, intraocular pressure, slit-lamp examination, and corneal fluorescein staining. Examinations of the central corneal thickness, corneal sensitivity, and nerve fiber regeneration were performed at each visit at 4, 8, 12, 20weeks and 6months, respectively, after initiating rhNGF treatment. All enrolled patients were diagnosed with NK at stage2 (7 eyes, 63.6%) or stage3 (4 eyes, 36.4%) and responded to rhNGF treatment. Five of 11 (45.5%) and 9 of 11 eyes (81.8%) achieved complete corneal epithelial healing after 4 and 8weeks, respectively. All 11 eyes (100%) achieved complete corneal healing after 12weeks. There was also a significant reduction in the corneal ulcer area during each visit (P < 0.001), as well as in the corneal fluorescein staining score (P < 0.010). There was a significant improvement in corneal sensation when compared to the baseline (P < 0.050). Topical treatment with rhNGF effectively promoted the complete corneal healing of persistent epithelial defects and corneal ulcers in patients with recalcitrant NK in oGVHD and viral infection.

Corneal Superficial Plaque Formation After Recombinant Human Nerve Growth Factor Use in a Patient With Neurotrophic Keratopathy and Limbal Stem Cell Deficiency From Mucous Membrane Pemphigoid.

The aim of this study was to report a rare observation of corneal superficial plaque formation after topical recombinant human nerve growth factor (rhNGF) treatment for a nonhealing epithelial defect in a patient with advanced mucous membrane pemphigoid, limbal stem cell deficiency, and neurotrophic keratopathy. This study was a case report. A 72-year-old man with a complex course of mucous membrane pemphigoid, leading to cicatrizing keratoconjunctivits, limbal stem cell deficiency, and neurotrophic keratopathy presented with a recurrent persistent epithelial defect in the right eye. After a long course of unsuccessful epithelial healing, despite various treatment modalities, he was administered topical rhNGF (cenegermin 0.002%; Oxervate, Dompé US Inc., Boston, MA) which successfully resolved the epithelial defect. However, on day 22 posttreatment, an unusual white, thick, adherent corneal superficial plaque formed. rhNGF was stopped and the plaque was carefully removed. Subsequently, there was no recurrence, and the patient's epithelial healing remained stable. Although the successful resolution of the persistent epithelial defect with rhNGF administration was notable, the development of the unusual epithelial overgrowth emphasizes the importance of vigilant monitoring and evaluation when using rhNGF in complex ocular conditions. Making informed decisions on the timing of discontinuing rhNGF can lead to desirable effects of the drug while mitigating additional side effects when managing such challenging cases.

Effect of recombinant human nerve growth factor treatment on corneal nerve regeneration in patients with neurotrophic keratopathy.

Neurotrophic Keratopathy (NK) is a neurodegenerative corneal disease that results in diminished corneal sensation. Previous studies have found that Cenegermin 0.002%, a recombinant human nerve growth factor (rhNGF), improves corneal epithelial healing in stage 2 and 3 NK patients. However, rhNGF effect on corneal sensation and nerve regeneration has not been well established. Thus, this study aims to analyze the effect of rhNGF on corneal nerve regeneration using in vivo confocal microscopy (IVCM) and on corneal sensitivity in NK patients. This is a retrospective, longitudinal, case-control study that included patients with NK, treated with rhNGF for at least 4 weeks, with pre- and post-treatment IVCM images available for analysis. Chart reviews were conducted documenting prior medical and surgical history, clinical signs and symptoms, and corneal sensation using Cochet-Bonnet esthesiometry. Corneal nerve parameters were assessed by IVCM. Sex- and age-matched reference controls were selected from a database of healthy subjects for comparison. The study included 25 patients, with 22 (88%) stage 1, two (8%) stage 2, and 1 (4%) stage 3 NK patients, with a median age of 64 years (range: 30-93 years). Total, main, and branch nerve densities [median (range) in mm/mm2] were lower in the NK group pre-treatment [2.3 (0.0-21.1); 1.7 (0.0-13.0); 0.5 (0.0-10.2); respectively] vs. controls [22.3 (14.9-29.0); 10.1 (3.2-15.4); and 12.1 (6.2-18.4), (p < 0.0001 for all), respectively]. Post-treatment nerve densities increased compared to pre-treatment to 5.3 (0.0-19.4, p = 0.0083) for total, 3.5 (0.0-13.2, p = 0.0059) for main, and 2.0 (0.0-10.4, p = 0.0251) for branch nerves, but remained lower than controls (p < 0.0001 for all). Corneal sensation increased from 2.3 ± 1.1 cm pre-treatment to 4.1 ± 1.4 cm post-treatment (p = 0.001). Median best corrected visual acuity significantly increased following rhNGF treatment from 0.4 (0.0-1.6) to 0.12 (-0.1 to 1.6) (p = 0.007). Patients with NK treated with at least 4 weeks of rhNGF, showed a significant increase in corneal nerve densities after treatment. A significant increase in corneal sensation, as well as best corrected visual acuity, was observed following treatment.

Ocular adverse events of cenegermin used in neurotrophic keratopathy: an analysis of the FDA adverse event reporting system database

ABSTRACT Background Cenegermin, a recombinant human nerve growth factor, is an orphan drug approved for neurotrophic keratitis. The safety information on the label is incomplete, and the adverse reactions noted are mostly mild and tolerable. However, the occurrence of painful epithelial plagues and irreversible corneal deposits after cenegermin usage have been reported. Real-world data on long-term ocular safety are lacking. We aimed to assess the cenegermin-associated eye safety profile in the FDA pharmacovigilance database. Methods The signals of cenegermin-related ocular adverse events (AEs) from 2018 to 2022 were quantified using the reporting odds ratio (ROR) and information component (IC). The grading system was used to prioritize the signals. Results We identified 3288 cases of cenegermin-related ocular AEs and 56 positive ocular-related signals. Fifty unexpected signals of ocular AE were identified. Eye ulcer was classified as a designated medical event. Twenty AEs, including corneal perforation, eye infection, corneal deposits, and eye inflammation, were recognized as important medical event. The median onset time for ocular AEs was 6 days (interquartile range [IQR]: 1–29 days). Conclusion This study revealed new cenegermin-related ocular AE signals. Clinical practice requires close monitoring to early identify and manage adverse reactions that may cause occurrence of serious irreversible consequences.

Effective regeneration of rat sciatic nerve using nanofibrous scaffolds containing rat ADSCs with controlled release of rhNGF and melatonin molecules for the treatment of peripheral injury model

Different therapeutic strategies have been designed and developed for the repair and regeneration of peripheral nerve injury (PNI) tissue as a result of advancements in tissue engineering and regenerative medicine. Due to its versatility, controlled delivery and administration of multifunctional therapeutic agents can be regarded of as an effective strategy in treating nerve injury. In this study, melatonin (Mel) molecules and recombinant human nerve growth factor (rhNGF) were loaded on the surface and in the core of polycaprolactone/chitosan (PCL/CS) blended nanofibrous scaffold. To simulate the in vivo microenvironment, a dual-delivery three-dimensional (3-D) nanofibrous matrix was developed and the in vitro neural development of stem cell differentiation process was systematically examined. The microscopic technique with acridine orange and ethidium bromide (AO/EB) fluorescence staining method was used to establish the adipose-derived stem cells (ADSCs) differentiation and cell–cell communications, which demonstrated that the effective differentiation of the ADSCs with nanofibrous matrix. As investigated observations, ADSCs differentiation was further evident through cell migration assay and gene expression analysis. According to the biocompatibility analysis, the nanofibrous matrix did not trigger any adverse immunological reactions. Based on these characteristics, a 5-week in vivo investigation examined the potential of the developed nanofibrous matrix in the regeneration of sciatic nerve of rats. Additionally, compared to the negative control group, the electrophysiological and walking track analyses demonstrated improved sciatic nerve regeneration. This study demonstrates the nanofibrous matrix's ability to regenerate peripheral nerves.

Combined treatment of nerve growth factor and transcranical direct current stimulations to improve outcome in children with vegetative state after out-of-hospital cardiac arrest

BackgroundOut-of-hospital cardiac arrest (OHCA) is one of the most dramatic events in pediatric age and, despite advanced neurointensive care, the survival rate remains low. Currently, no effective treatments can restore neuronal loss or produce significant improvement in these patients. Nerve Growth Factor (NGF) is a neurotrophin potentially able to counteract many of the deleterious effects triggered by OHCA. Transcranial Direct Current Stimulation (tDCS) has been reported to be neuroprotective in many neurological diseases, such as motor deficit and cognitive impairment. Children with the diagnosis of chronic vegetative state after OHCA were enrolled. These patients underwent a combined treatment of intranasal administration of human recombinant NGF (hr-NGF), at a total dose of 50 gamma/kg, and tDCS, in which current intensity was increased from zero to 2 mA from the first 5 s of stimulation and maintained constant for 20 min. The treatment schedule was performed twice, at one month distance each. Neuroradiogical evaluation with Positron Emission Tomography scan (PET), Single Photon Emission Computed Tomography (SPECT), Electroencephalography (EEG) and Power Spectral Density of the brain (PSD) was determined before the treatment and one month after the end. Neurological assessment was deepened by using modified Ashworth Scale, Gross Motor Function Measure, and Disability Rating Scale.ResultsThree children with a chronic vegetative state secondary to OHCA were treated. The combined treatment with hr-NGF and tDCS improved functional (PET and SPECT) and electrophysiological (EEG and PSD) assessment. Also clinical conditions improved, mainly for the reduction of spasticity and with the acquisition of voluntary finger movements, improved facial mimicry and reaction to painful stimuli. No side effects were reported.ConclusionsThese promising preliminary results and the ease of administration of this treatment make it worthwhile to be investigated further, mainly in the early stages from OHCA and in patients with better baseline neurological conditions, in order to explore more thoroughly the benefits of this new approach on neuronal function recovery after OHCA.

Biomechanical microenvironmental stimulating effect of pulsed electromagnetic field on the regeneration of crush injured rat sciatic nerve.

This study evaluated the biomechanical microenvironmental stimulating effect of pulsed electromagnetic field (PEMF) on the regeneration of crush-injured rat sciatic nerve, when combined with bone marrow mesenchymal stem cells (BMSCs) and recombinant human nerve growth factor (rhNGF-β), in the form of an adenoviral vector-mediated NGF. Sprague-Dawley rats were equally distributed into six groups; PBS, BMSC, NGF-Ad + BMSC, PEMF + PBS, PEMF + BMSC and PEMF + NGF-Ad + BMSC. The PBS group received PBS (volume: 10μL/rat), the BMSC group with BMSCs (1 × 106cell/10μL/rat) and NGF-Ad group with the rhNGF-β Ad infected BMSCs (1 × 106 cell/10μL/rat) immediate after right sciatic nerve crush injury. The PEMF groups were exposed to PEMF of 1mT, 50Hz, 1h/day. The rats were observed for 3weeks. PEMF alone did not showed the positive effect compared with negative control group. The groups transplanted with BMSCs showed higher axonal regeneration compared with the groups without transplantation of the cells whether BMSC was infected with NGF-Ad or not and whether the animals received PEMF. PEMF + NGF-Ad + BMSC group showed the significantly highest number of axons than the other groups. Functionally, all groups showed marked improvement at 3weeks postoperatively although the difference was not statistically significant among the groups. PEMF showed the positive effect when combined with BMSC and NGF-ad in aspect of number of axons. Therefore, combining the microenvironment stimulation methods of PEMF and conventional methods such as transplantation of stem cells and growth factor could be considered for the regeneration methods in the nerve damage.

Acute intranasal treatment with nerve growth factor limits the onset of traumatic brain injury in young rats.

Traumatic brain injury (TBI) comprises a primary injury directly induced by impact, which progresses into a secondary injury leading to neuroinflammation, reactive astrogliosis, and cognitive and motor damage. To date, treatment of TBI consists solely of palliative therapies that do not prevent and/or limit the outcomes of secondary damage and only stabilize the deficits. The neurotrophin, nerve growth factor (NGF), delivered to the brain parenchyma following intranasal application, could be a useful means of limiting or improving the outcomes of the secondary injury, as suggested by pre-clinical and clinical data. We evaluated the effect of acute intranasal treatment of young (20-postnatal day) rats, with NGF in a TBI model (weight drop/close head), aggravated by hypoxic complications. Immediately after the trauma, rats were intranasally treated with human recombinant NGF (50 μg·kg-1 ), and motor behavioural test, morphometric and biochemical assays were carried out 24 h later. Acute intranasal NGF prevented the onset of TBI-induced motor disabilities, and decreased reactive astrogliosis, microglial activation and IL-1β content, which after TBI develops to the same extent in the impact zone and the hypothalamus. Intranasal application of NGF was effective in decreasing the motor dysfunction and neuroinflammation in the brain of young rats in our model of TBI. This work forms an initial pre-clinical evaluation of the potential of early intranasal NGF treatment in preventing and limiting the disabling outcomes of TBI, a clinical condition that remains one of the unsolved problems of paediatric neurology.

Clinical observation of recombinant human nerve growth factor in the treatment of neurotrophic keratitis.

To characterize changes of corneal nerve morphology and tear indices in patients with neurotrophic keratitis (NK) treated with recombinant human nerve growth factor (rhNGF). In a prospective observational study, six patients (nine eyes) were locally treated with rhNGF. Visual acuity, corneal fluorescein staining score, the heights of the tear river, lipid layer thickness (LLT), tear ferning (TF) test, conjunctival impression cytology (CIC) examination, the densities of cornea subbasal nerve fibers were determined before and after treatment. Compared with baseline, there was a significant difference in corneal fluorescence staining scores (P<0.01); all patient corneal epithelial defects recovered completely within 8wk, but there was no significant improvement in the height of the tear river (P=0.202). LLT was significantly increased when compared with baseline (P=0.042); however, the function of conjunctival goblet cells and mucin content did not significantly improve using the TF test and CIC examination (P=0.557, P=0.539). After 8wk of treatment, the average corneal subbasal nerve fiber density increased significantly (P<0.01), as did the number of corneal nerve fiber branches (P=0.001). RhNGF can increase the density of corneal subbasal nerve fibers, promote the healing of persistent corneal epithelial defects and corneal ulcers in patients with NK, also improving tear function partially.

A, B, C's of Trk Receptors and Their Ligands in Ocular Repair.

Neurotrophins are a family of closely related secreted proteins that promote differentiation, development, and survival of neurons, which include nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4. All neurotrophins signal through tropomyosin receptor kinases (TrkA, TrkB, and TrkC) which are more selective to NGF, brain-derived neurotrophic factor, and neurotrophin-3, respectively. NGF is the most studied neurotrophin in the ocular surface and a human recombinant NGF has reached clinics, having been approved to treat neurotrophic keratitis. Brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4 are less studied neurotrophins in the ocular surface, even though brain-derived neurotrophic factor is well characterized in glaucoma, retina, and neuroscience. Recently, neurotrophin analogs with panTrk activity and TrkC selectivity have shown promise as novel drugs for treating dry eye disease. In this review, we discuss the biology of the neurotrophin family, its role in corneal homeostasis, and its use in treating ocular surface diseases. There is an unmet need to investigate parenteral neurotrophins and its analogs that activate TrkB and TrkC selectively.

Magic Bullets: The Coming Age of Meaningful Pharmacological Control of the Corneal Responses to Injury and Disease.

Corneal injuries from chemical burns, mechanical trauma, infections, immunological rejections, surgical complications, and some diseases are commonly associated with persistent epithelial defects (PED), neurotrophic epitheliopathy, scarring fibrosis, corneal neovascularization (CNV), and/or corneal endothelial damage that lead to vision loss. Several Food and Drug Administration (FDA) approved medications have recently become available, are currently in clinical trials, or are likely to enter clinical trials in the near future. For example, a 2-week course of topical human recombinant nerve growth factor is frequently an effective treatment for corneal neurotrophic epitheliopathy associated with PEDs. Topical losartan, an angiotensin converting enzyme II receptor antagonist that also inhibits TGF beta signaling, has been shown to effectively decrease myofibroblast generation and scarring fibrosis in alkali burn injury and Descemetorhexis rabbit models. Small molecule topical tyrosine kinase inhibitors, such as sunitinib and axitinib, FDA approved as chemotherapeutic agents to treat specific cancers, have also been found to be effective topical inhibitors of CNV in animal and human trials. Rho-kinase inhibitors, such as ripasudil and netarsudil, that are currently approved agents for the treatment of glaucoma in some countries, have been shown to stimulate corneal endothelial proliferation in animal studies and human trials, and may accelerate the regeneration of Descemet's membrane. These agents, as well as other drugs in development, will be used in targeted combinations to treat corneal pathophysiology associated with epithelial healing disorders, stromal scarring fibrosis, CNV, and corneal endothelial injury during the next decade.

Efficacy of Recombinant Human Nerve Growth Factor in Stage 1 Neurotrophic Keratopathy

Topical rhNGF therapy was well-tolerated and resulted in significantly increased best corrected vision acuity, corneal fluorescein staining, as well as increased corneal nerve density by IVCM in 17 patients with Stage 1 NK.

Evaluation of clinical and histological effects of KGF-2 and NGF on corneal wound healing in an experimental alkali burn rabbit model

Endogenously produced peptide growth factors such as keratinocyte growth factor-2 (KGF-2) and nerve growth factor (NGF) play a key role in the natural corneal wound healing process. However, this self-healing ability of the corneal tissue is often impaired in cases of severe corneal damage, as in corneal alkali injuries. In the present study, we investigated the clinical and histopathological effects of topical recombinant human keratinocyte growth factor-2 and nerve growth factor treatments in a rabbit model of corneal alkali burn. After induction of an alkali burn, 24 rabbits were divided equally into three groups: control group, KGF-2 group, and NGF group. Clinical parameters including epithelial healing, opacification, neovascularization and central corneal thickness were evaluated on the first (D1), seventh (D7) and fourteenth (D14) days after injury. Corneal histology was performed using hematoxylin/eosin (H&E) and Masson's Trichrome stains. Immunohistochemical staining for matrix metalloproteinase-2 (MMP-2), MMP-9 and transforming growth factor-β (TGF-β) was performed. On D14, the percentage of epithelial defect and opacity were significantly less in the KGF-2 and NGF groups compared to the control group (p < 0.05). There was no significant difference between the groups in central corneal thickness. In the evaluation of neovascularization on D14, the NGF group was significantly less vascularized than the control group (p = 0.011). Histological examination showed a significant increase in stromal edema and inflammation in the control group compared to both treatment groups (p < 0.05). There was also a significant difference between the NGF and control groups in histological evaluation of epithelial repair and vascularization (p < 0.05). When immunoreactivity of MMP-2, MMP-9 and TGF-β was examined, there was a significant increase in the control group compared to the NGF group (p < 0.05). Taken together, both NGF and KGF-2 treatments were effective for early re-epithelialization and decrease in inflammation, opacity and neovascularization after corneal alkali burn. The inhibitory effect of NGF treatment on chemical-induced neovascularization was found to be superior to KGF-2 treatment.

Bioengineered Human Stromal Lenticule for Recombinant Human Nerve Growth Factor Release: A Potential Biocompatible Ocular Drug Delivery System.

Small incision lenticule extraction (SMILE), is a surgical procedure for the myopia correction, during which a corneal stromal lenticule is extracted. Given that we have previously demonstrated how this discarded tissue could be repurposed as a bio-scaffold for stromal engineering, this study aimed to explore its use as an ocular drug delivery system of active molecules, using neurotrophic factor Nerve Growth Factor (NGF). We employed human stromal lenticules directly collected from healthy donors undergoing SMILE. Following a sodium dodecylsulfate (SDS) treatment, decellularized lenticules were incubated with a suspension of polylactic-co-glycolic-acid (PLGA) microparticles (MPs) loaded with recombinant human NGF (rhNGF-MPs). Fluorescent MPs (Fluo-MPs) were used as control. Data demonstrated the feasibility to engineer decellularized lenticules with PLGA-MPs which remain incorporated both on the lenticules surface and in its stromal. Following their production, the in vitro release kinetic showed a sustained release for up to 1 month of rhNGF from MPs loaded to the lenticule. Interestingly, rhNGF was rapidly released in the first 24 h, but it was sustained up to the end of the experiment (1 month), with preservation of rhNGF activity (around 80%). Our results indicated that decellularized human stromal lenticules could represent a biocompatible, non-immunogenic natural scaffold potential useful for ocular drug delivery. Therefore, combining the advantages of tissue engineering and pharmaceutical approaches, this in vitro proof-of-concept study suggests the feasibility to use this scaffold to allow target release of rhNGF in vivo or other pharmaceutically active molecules that have potential to treat ocular diseases.

The effects of CHF6467, a new mutated form of NGF, on cell models of human glioblastoma. A comparison with wild-type NGF

CHF6467 is a mutated form of human recombinant nerve growth factor (NGF). The mutation selectively disrupts the binding of NGF to its p75NTR receptor while maintaining the affinity toward TrkA receptor. Because of such different profile of receptor interaction, CHF6467 maintains unaltered the neurotrophic and neuroprotective properties of wild-type NGF but shows reduced algogenic activity. In this study, we investigated the effects of CHF6467 on mortality, proliferation, cell-damage and migration in three human glioblastoma cell lines (U87MG, T98G, LN18), and in the rat astrocytoma C6 cells. Both CHF6467 and wild-type NGF, given in the range 1-50 ng/ml, did not modify cell proliferation, metabolism and migration, as well as the number of live/dead cells. The present in vitro data are predictive of a lack of tumorigenic activity by both wild-type NGF and CHF6467 on these cell types in vivo, and warrant for CHF6467 further clinical development.

Long-term clinical efficacy of topical treatment with recombinant human nerve growth factor in neurotrophic keratopathy: a novel cure for a rare degenerative corneal disease?

BackgroundNeurotrophic keratopathy (NK) is a rare, degenerative ocular disease characterized by reduction or loss of corneal sensitivity and development of non-healing corneal epithelial defects and ulcers. Cenegermin, a recombinant human nerve growth factor (rhNGF) eye drop solution, is the first drug approved for the treatment of NK. The aim of our study is to evaluate the long-term efficacy of this innovative topical treatment in patients with NK.MethodsRetrospective, consecutive, observational case series study from a single-center setting (Department of Sense Organs, University Sapienza of Rome, Rome, Italy). 18 patients with diagnosis of stage 2 or 3 NK, treated with Cenegermin 20 mcg/ml eye drops were followed for up to 48 months. Recurrence of lesion during follow-up was evaluated at 12, 24, 36, and 48 months. In addition, corneal sensitivity, Schirmer tear test, and visual acuity (VA) were recorded at baseline, end of treatment, and at 12, 24, 36, and 48 months.ResultsThree patients experienced recurrence of persistent epithelial defects (PEDs) within 12 months and one patient experienced recurrence of a corneal ulcer within 36 months. Corneal sensitivity was significantly improved at all timepoints (P < 0.05). Significant improvements in visual acuity and tear production were seen at the completion of treatment as well as at 12, 24, and 36 months (P < 0.05) when compared to baseline.ConclusionsA single 8-week treatment regimen of Cenegermin eye drops has clinical efficacy that can persist for up to 48 months. The long-term clinical utility of treatment with Cenegermin for NK was demonstrated through the low rate of lesion recurrence along with improvements in corneal sensitivity and tear production.