Application of Umbilical Cord Serum Eyedrops for the Treatment of Neurotrophic Keratitis

Corneal Neurotization: Essentials for The Facial Paralysis Surgeon

Deficits in corneal innervation lead to neurotrophic keratopathy (NK). NK is frequently associated with facial palsy, and corneal damage can be accelerated by facial palsy deficits. Corneal nerves are important regulators of limbal stem cells, which play a critical role in epithelial maintenance and healing. Nonsurgical treatments of NK have undergone recent innovation, and growth factors implicated in corneal epithelial renewal are a promising therapeutic avenue. However, surgical intervention with corneal neurotization (CN) remains the only definitive treatment of NK. CN involves the transfer of unaffected sensory donor nerve branches to the affected cornea, and a variety of donor nerves and approaches have been described. CN can be performed in a direct or indirect manner; employ the supraorbital, supratrochlear, infraorbital, or great auricular nerves; and utilize autograft, allograft, or nerve transfer alone. Unfortunately, comparative studies of these factors are limited due to the procedure's novelty and varied recovery timelines after CN. Regardless of the chosen approach, CN has been shown to be a safe and effective procedure to restore corneal sensation and improve visual acuity in patients with NK.

Combined therapeutic use of umbilical cord blood serum and amniotic membrane in diabetic wounds

Diabetic wounds are hard-to-heal due to complex multifactorial dysregulation within the micro-environment, necessitating the development of novel regenerative approaches to stimulate healing. This study investigated whether the combined therapeutic application of two novel cellular tissue products, namely a decellularized collagen-rich amniotic membrane (AmR) and growth factor-rich umbilical cord blood serum (UCBS) could have a positive synergistic effect on long-term healing outcomes by stimulating both superficial wound closure and wound bed regeneration. Full thickness excisional wounds were induced on obese diabetic mice (B6.Cg-lepob/J, ob/ob, n = 23) and treated with either: 1) Standard wound care (control); 2) UCBS; 3) AmR or 4) UCBS + AmR. Macroscopic wound closure was assessed on days 0, 3, 7, 10 and 14 post wounding. To determine the potential impact on wound recurrence, endpoint analysis was performed to determine both the overall quality of healing histologically as well as the molecular state of the wounds on day 14 via proteomic analysis. The data demonstrated the presence of both healers and non-healers. Re-epithelization took place in the healers of all treatment groups, but underlying tissue regeneration was far more pronounced following application of the combined treatment (UCBS + AmR), suggesting improved quality of healing and potentially a reduced change of recurrence long term. In non-healers, wounds failed to heal due to excessive slough formation and a reduction in LTB4 expression, suggesting impaired antimicrobial activity. Care should thus be taken since the cellular tissue product therapy could pose an increased risk for infection in some patients.

Blood-Derived Eye Drops for the Treatment of Corneal Neuropathic Pain

Blood-derived preparations, including autologous or allogenic serum, umbilical cord serum/plasma, and platelet-rich plasma eye drops, contain various growth factors, cytokines, and immunoglobulins that resemble natural tears. These components play important roles in corneal cell migration, proliferation, and wound healing. Blood-derived eye drops have demonstrated clinical effectiveness across a spectrum of ocular surface conditions, encompassing dry eye disease, Sjögren's syndrome, graft-versus-host disease, and neuropathic corneal pain (NCP). Currently, management of NCP remains challenging. The emergence of blood-derived eye drops represents a promising therapeutic approach. In this review, we discuss the benefits and limitations of different blood-derived eye drops, their mechanisms of action, and treatment efficacy in patients with NCP. Several studies have demonstrated the clinical efficacy of autologous serum eye drops in relieving pain and pain-like symptoms, such as allodynia and photoallodynia. Corneal nerve parameters were also significantly improved, as evidenced by increased nerve fiber density, length, nerve reflectivity, and tortuosity, as well as a decreased occurrence of beading and neuromas after the treatment. The extent of nerve regeneration correlated with improvement in patient-reported photoallodynia. Cord plasma eye drops also show potential for symptom alleviation and corneal nerve regeneration. Future directions for clinical practice and research involve standardizing preparation protocols, establishing treatment guidelines, elucidating underlying mechanisms, conducting long-term clinical trials, and implementing cost-effective measures such as scaling up manufacturing. With ongoing advancements, blood-derived eye drops hold promise as a valuable therapeutic option for patients suffering from NCP.

Neurotrophic keratopathy: General features and new therapies

Neurotrophic keratopathy is an uncommon degenerative corneal disorder characterized by compromised corneal sensory innervation resulting in the formation of epithelial defects and nonhealing corneal ulcers. Various treatment modalities are available to stabilize disease progression, improve patient well-being, and prevent vision loss. For eligible patients, medical and surgical reinnervation have emerged as pioneering therapies, holding promise for better management. We present a comprehensive review of the disorder, providing an update relevant to ophthalmologists on pathogenesis, diagnosis, treatment options, and novel therapies targeting pathophysiological pathways.

Comparative evaluation of platelet-rich plasma, autologous blood serum, and umbilical cord serum for corneal healing after penetrating keratoplasty in New Zealand rabbits

This study aimed to evaluate the effects of platelet-rich plasma (PRP), autologous blood serum (ABS), and umbilical cord serum (UCS) on corneal healing following penetrating keratoplasty (PK). A total of 120 New Zealand white rabbits, forty were designated as donors, while the remaining eighty rabbits were randomly divided into four groups after undergoing PRP Group (n = 20), ABS Group (n = 20), UCS Group (n = 20) and Control Group (n = 20). Corneal opacity score, corneal vascularization, corneal staining, histopathological analysis, and immunohistochemical analysis (including CD4+, CD8+, and major histocompatibility complex [MHC] II) were assessed at postoperative 1, 2, 3, and 12 weeks. The results showed that corneal opacity score and corneal vascularization did not differ significantly among the groups. However, corneal staining was found to be statistically higher in the PRP group (0.40 ± 0.60) compared to the other groups (p = 0.011). Immunohistochemical examination revealed no significant differences in CD4+, CD8+, and MHC II levels among the groups. Notably, in all groups, CD4+, CD8+, and MHC II levels were significantly higher at 12 weeks compared to other time points. PRP, ABS, and UCS demonstrated positive effects on corneal healing after PK. However, among the three products, PRP exhibited a superior healing effect compared to ABS and UCS crucial in the postoperative period following PK procedures, as they significantly impact visual quality, graft transparency, graft survival, and prevention of stromal resorption caused by infections. Despite the avascular nature of the cornea and its immune privilege, failure to resolve epithelial defects (ED) commonly observed after PK can result in irreversible scarring and ulceration, leading to graft rejection. While epithelial defects are observed in 14-100% of cases on the first postoperative day, approximately 3-7% of them persist as non-healing ED in subsequent periods. In conclusion, our study demonstrated that PRP, ABS, and UCS have a positive effect on corneal healing after PK.

Corneal reinnervation in patients with severe neurotrophic keratopathy secondary to herpes zoster ophthalmicus after treatment with autologous serum tear drops

Purpose

To study potential corneal reinnervation and recovery of corneal sensation in patients with severe neurotrophic keratopathy (NK) secondary to herpes zoster ophthalmicus (HZO) after treatment with topical autologous serum tears (AST).

Method

Four cases of HZO with severe NK were followed clinically and by serial laser in vivo confocal microscopy (IVCM, HRT3/RCM, Heidelberg Engineering) before and during treatment with 20% AST drops eight times a day. Two masked observers reviewed the IVCM images and assessed corneal nerve alterations.

Results

At baseline, all patients had complete loss of corneal sensation. In addition, IVCM showed complete lack of the subbasal corneal nerve plexus in all patients. All four patients were refractory to conventional therapies and were treated with AST drops. All patients demonstrated significant nerve regeneration by IVCM within 3-7 months of treatment. The total nerve density increased to a mean ± SEM of 10,085.88±2,542.74 μm/mm2 at the last follow up. Corneal sensation measured by Cochet-Bonnet esthesiometry improved to a mean ± SEM of 3.50±1.30 cm. Interestingly, 3 of 4 patients developed stromal keratitis with ulceration within weeks of corneal reinnervation, which was reversed by adding topical steroids.

Conclusion

Autologous serum tears are effective in restoring corneal subbasal nerves and sensation in patients with severe NK secondary to HZO. However, this group of patients may require concurrent topical immunomodulation and antiviral therapy while on AST to prevent stromal keratitis.

Cord blood-derived biologics lead to robust axonal regeneration in benzalkonium chloride-injured mouse corneas by modulating the Il-17 pathway and neuropeptide Y

BACKGROUND

Umbilical cord blood-derived therapeutics, such as serum (UCS) and platelet-rich plasma (UCPRP), are popular treatment options in clinical trials and can potentially be utilized to address a clinically unmet need caused by preservatives, specifically benzalkonium chloride (BAK), present in ophthalmic formulations. As current clinical interventions for secondary injuries caused by BAK are suboptimal, this study will explore the feasibility of utilizing UCS and UCPRP for cornea treatment and investigate the underlying mechanisms associated with this approach.

METHODS

Mice's corneas were administered BAK to induce damage. UCS and UCPRP were then utilized to attempt to treat the injuries. Ocular tests were performed on the animals to evaluate recovery, while immunostaining, RNA-seq, and subsequent bioinformatics analysis were conducted to investigate the treatment mechanism.

RESULTS

BAK administration led to widespread inflammatory responses in the cornea. Subsequent treatment with UCS and UCPRP led to the downregulation of immune-related 'interactions between cytokine receptors' and 'IL-17 signaling' pathways. Although axonal enhancers such as Ngf, Rac2, Robo2, Srgap1, and Rock2 were found to be present in the injured group, robust axonal regeneration was observed only in the UCS and UCPRP treatment groups. Further analysis revealed that, as compared to normal corneas, inflammation was not restored to pre-injury levels post-treatment. Importantly, Neuropeptide Y (Npy) was also involved in regulating immune responses, indicating neuroimmune axis interactions.

CONCLUSIONS

Cord blood-derived therapeutics are feasible options for overcoming the sustained injuries induced by BAK in the cornea. They also have potential applications in areas where axonal regeneration is required.

[Comparison of the Effect of Autologous Serum on Therapy Resistant Corneal Erosions and Ulcers on the Corneal Graft vs. the Patient's Own Cornea]

PURPOSE

The aim of this study is to compare the healing of corneal epithelial defects or ulcers on the corneal graft in comparison with the patient's own cornea after treatment with 100%, undiluted autologous serum eye drops.

METHODS

In a retrospective study over 7 years, we analysed 263 treatments with autologous serum eye drops of persistent corneal epithelial defects (erosions [88%] vs. ulcers [12%]). We compared the epithelial healing tendency of patients with defects on their own cornea (51.9%) vs. patients who had previously undergone penetrating keratoplasty (48.1%). Complete epithelial healing during the 28 days of treatment was considered as therapeutic success. In addition, the recurrence rate of the epithelial defects after finishing the therapy was analysed.

RESULTS

88.2% of the epithelial defects healed during 28 days of therapy. The recurrence rate during follow-up was 5.1%. There was no significant difference with respect to success rate between corneal defects on the patient's own cornea (87.8%) and on the graft (88.6%; p = 0.137). There was a significantly lower success rate for corneal ulcers (74.2%) than for erosions (90.3%; p < 0.001). The recurrence rate of erosions was 4.4%, vs. 4.3% in ulcers during follow-up.

CONCLUSION

The results of our study suggest that autologous serum eye drops are a non-invasive and safe alternative treatment for persistent corneal epithelial defects - with no significant difference in patients with a defect on their own cornea vs. defects on the corneal graft. The success rate, but not the recurrence rate, is significantly worse in ulcers than in erosions.

Efficacy of Plasma Rich in Growth Factors (PRGF) in Stage 1 Neurotrophic Keratitis

Background/Aims

Neurotrophic keratitis (NK) is a neurodegenerative disease that can lead to corneal hypoesthesia, decreased tear production, and epitheliopathy. Based on the severity of ocular surface damage, NK is classified into 3 stages. Stage 1 NK is characterized by superficial punctate keratopathy, tear film instability, and reduced corneal sensation. The therapeutic efficacy of PRGF eye drops for NK stages 2 and 3 has been previously reported. In this study, we evaluated the efficacy and safety of autologous PRGF eye drops in improving corneal sensitivity and other ocular surface clinical signs in patients with stage 1 NK.

Methods

Retrospective chart review.

Results

26 eyes of 15 stage 1 NK patients (seven males, eight females), aged 76.3 ± 12.1 years, were included in the study. The mean treatment duration was 2 ± 1.8 months. With PRGF treatment, corneal sensitivity increased from 2.8 to 4.5 cm in 53.8% (14/26) (p < 0.01), TBUT increased from 3.6 to 5.0 s in 69.2% (18/26) (p < 0.01), and Schirmer score increased from 13.7 to 16.8 mm in 80.7% (21/26) of treated eyes (p < 0.01). Similarly, an improvement in corneal staining (punctate epithelial erosions) and MMP-9 levels was seen in 80.7% (n = 21) and 65.4% (n = 17) of treated eyes, respectively. BCVA improvement was seen in 26.9% of treated eyes (n = 7).

Conclusions

This study demonstrates the effective role of PRGF therapy in recovering corneal sensation and tear film function and in the healing of corneal erosions in stage 1 NK patients.

Therapeutic Profile of Human Umbilical Cord Blood Serum and Autologous Serum Therapies in Treatment of Ocular Surface Disorders: A Pilot Study

Purpose: Umbilical cord blood serum (UCBS) is an effective adjunctive treatment along with conventional therapy in ocular surface disorders (OSDs). It aids in rapid ocular surface restoration thereby achieving epithelial integrity, in addition to improvement in subjective and objective parameters. The study aims to compare the efficacy of human umbilical cord blood serum and autologous serum (AS) in treatment of OSD. Methods: A prospective randomized study was conducted on 101 eyes diagnosed with OSD resulting from dry eye disease (DED; n = 40), acute chemical burn (ACB; n = 21), and ocular allergy (OA; n = 40). Randomization was done in Group I, administered with AS, and Group II with UCBS. Outcomes evaluated were visual acuity (VA), eye sensation score (ESS), ocular surface disease index (OSDI), tear break-up time (TBUT), Schirmer's value, Corneal Fluorescein Score, epithelial defect, limbal ischemia, corneal clarity (CC), and improvement in grade of severity. Statistical analysis was done using Wilcoxon signed-rank, Wilcoxon rank sum, Chi-square, and Z-test with a significance level (P ≤ 0.05). Results: In DED, Group II showed significant improvement in VA, ESS, and OSDI by the 7th day, whereas the mean Schirmer, TBUT, and corneal fluorescein staining score improved by 3 months. In ACB, Group II showed improvement in VA, reepithelialization, reduction in limbal ischemia, and CC by 3 months. In OA, Group II showed improvement in ESS by day 7. Conclusion: Human umbilical cord blood serum is more effective than AS in restoring ocular surface.

Treatment of Severe Dry Eye in Stevens-Johnson Syndrome with Umbilical Cord Serum Eye Drops

PURPOSE

To evaluate the efficacy and safety of umbilical cord serum eye drops for dry eyes in ocular Stevens-Johnson Syndrome (SJS).

PATIENTS AND METHODS

A pre-post test study with umbilical cord serum (UCS) eye drop for ocular SJS patient with moderate to severe dry eyes. Study was conducted at Kirana Cipto Mangunkusumo General Hospital from June 2020 to December 2020. A total of five patients (five eyes) with a diagnosis of SJS more than 6 months, dry eye symptoms, and abnormal tear stability test results were included in the study. Each patient was asked to instill UCS drop into the affected eye six times daily. Evaluation of ocular symptoms with ocular surface disease index (OSDI) questionnaires, non-invasive tear break-up time (NIBUT), Schirmer I, and keratoepitheliopathy scores was administered before applying UCS drop and at week 2 and 4 of eye drop use.

RESULTS

From June 2020 to December 2020, five eyes of five patients were evaluated in this study. Patients were aged from 22 to 71 years old with history of SJS over periods from 1 to 35 years. Three patients underwent ocular surgeries prior to the study. After four weeks of treatment, symptoms score, Schirmer I, and keratoepitheliopathy scores improved significantly, while NIBUT scores improved insignificantly. No side effects were noted during treatment.

CONCLUSION

Administration of UCS eye drop was effective in improving symptoms and signs of dry eye in chronic SJS patients.

Neurotrophic keratopathy: current challenges and future prospects

Neurotrophic keratopathy (NK), or neurotrophic keratitis, is a degenerative condition that results from decreased innervation to the cornea. The cornea is innervated by the ophthalmic branch of the trigeminal nerve. Neurotrophic keratopathy is most commonly caused by herpes keratitis however, any condition that disrupts the normal corneal innervation can cause NK. Neurotrophic keratopathy is a clinical diagnosis and is classified into three stages based on the disease severity. Stage 1 has mild epithelial defects, such as punctate keratopathy, stage 2 disease has persistent epithelial defects, and stage 3 is defined by the presence of ulcers. Current treatment modalities consist of medical and surgical options. Stage 1 is treated with lubrication through artificial tears, eyelid taping, and punctal plug/cautery. Stage 2 treatment can involve therapeutic contact lenses, topical autologous or allogenic serum, tarsorrhaphy, botulinum toxin injections, and possibly anti-inflammatory medications. Stage 3 disease may require human nerve growth factor, amniotic membrane transplantation, conjunctival flap, or corneal neurotization. New therapies, such as matrix regenerating therapy, plasma rich in growth factors, Thymosin β4, Substance P/Insulin like growth factor-1, and nicergoline represent exciting future options.KEY MESSAGESNeurotrophic keratopathy is a rare degenerative disease defined by decreased innervation to the cornea that is associated with significant morbidity.Treatment options range from lubrication alone to various medical and surgical treatments.Matrix regenerating therapy, plasma rich in growth factors, Thymosin β4, Substance P/Insulin like growth factor-1, and nicergoline are exciting novel therapies that will influence how neurotrophic keratopathy is treated in the future.

Neurotization of the human cornea - A comprehensive review and an interim report

We present a comprehensive review of existing literature on surgical corneal neurotization (SCN) as a treatment modality for neurotrophic keratopathy (NK) with an interim report of seven cases where SCN was performed using the indirect approach and followed up till 18 months postoperatively to look for improvement in ocular surface, corneal sensations, and nerve regeneration by using in vivo confocal microscopy (IVCM). A literature search was performed for publications with keywords “corneal nerves,” “neurotization,” “esthesiometry,” “corneal anesthesia,” and “neurotrophic keratopathy.” All literature available till December 31, 2020 was reviewed and included to describe NK and its management options, particularly SCN. NK is associated with absent or reduced corneal sensations and is managed using a step-ladder algorithm ranging from medical management for symptomatic relief to surgical corneal neurotization. Both direct and indirect approaches of SCN have a favorable outcome with reduced surgical morbidity in the indirect approach using sural nerve graft. Post neurotization, corneal sensation recovery may take up to 3–6 months, while nerve regeneration on confocal microscopy can take as long as 6 months–1 year.

A multicenter report of the use of plasma rich in growth factors (PRGF) for the treatment of patients with ocular surface diseases in North America

PURPOSE

To investigate the efficacy and safety of plasma rich in growth factors (PRGF) eyedrops in the management of patients with ocular surface diseases in North America.

METHODS

Multicenter interventional case series of patients using PRGF eyedrops for the first time. A cohort of patients was analyzed for corneal staining score at initial visit and at 3 months of therapy with PRGF. Another cohort responded to a 10-item questionnaire that evaluated patients' satisfaction and safety, which included the symptom assessment questionnaire in dry eye (SANDE) score, after 6 months of PRGF treatment.

RESULTS

A total of 153 patients were analyzed. Of these, 102 were reviewed for corneal epitheliopathy and 99 patients responded to the questionnaire. The mean (±SD) age of the population was 63.7 ± 17 years and 72.5% were female. The clinical indications for PRGF usage were dry eye (60%), neurotrophic keratopathy (15%), dormant corneal ulcers (12%), limbal stem cell deficiency (10%), and cicatrizing conjunctivitis (4%). At the final visit, 74.3% of patients showed an improvement of their corneal staining. Those who had punctate epithelial erosions or epithelial defects were reduced from 76.5% to 47% and 23.5%-7.8% respectively (p < 0.0001). Symptoms, measured via SANDE score, significantly decreased from a median of 90 to 34.6 out of 100 points on follow-up (p < 0.0001). Only one patient (0.98%) complained of ocular burning sensation as a side effect.

CONCLUSIONS

This multicentric study demonstrates the safety and efficacy of the use of PRGF for treating signs and symptoms in patients with significant ocular surface diseases.

New Pharmacological Approaches for the Treatment of Neurotrophic Keratitis

Neurotrophic keratitis (NK) is a rare degenerative condition that is caused by damage to the trigeminal nerve, with partial or complete loss of corneal sensory innervation. The loss of innervation leads to impaired healing of corneal epithelium, which subsequently results in punctate epithelial erosions, persistent epithelial defects, corneal ulcers and corneal perforation. Management of NK is often supportive and aims to promote epithelial healing and prevent progression of disease. Multiple novel pharmacological approaches have been proposed to address the underlying pathophysiology of NK, which are discussed in this paper.

Equine Umbilical Cord Serum Composition and Its Healing Effects in Equine Corneal Ulceration

Background

Human autologous serum (AS) and umbilical cord serum (UCS) both contain growth and neurotrophic factors that promote corneal healing.

Aim

Our objectives were to compare equine AS and UCS cytokine and growth factor profiles and to assess the safety and clinical feasibility of the therapeutic use of UCS eye drops in cases of spontaneous complex ulcers.

Study Design

Prospective clinical trial.

Methods

Vitamin A insulin growth factor, platelet-derived growth factor-BB, transforming growth factor (TGF)-β1 (enzyme-linked immunosorbent assay), interleukin (IL)-1β, IL-6, interferon-γ, and monocyte chemoattractant protein 1 concentrations were determined in 10 AS collected from different horses and 10 UCS sampled at delivery. Six client-owned horses presenting with complex non-healing corneal defects of >5 mm² were included in a clinical trial and treated with conventional therapy and conditioned UCS drops for 8–15 days. Ulcer surface and time to complete epithelialization were recorded.

Results

Median concentrations of vitamin A, insulin growth factor, and platelet-derived growth factor-BB were not significantly different in AS compared with UCS (respectively, 14.5 vs. 12.05 μg/ml; 107.8 vs. 107.3 pg/ml; and 369.1 vs. 924.2 pg/ml). TGF-β1 median concentration in UCS was significantly higher than in AS (3,245 vs. 2571pg/ml) (p = 0.04). IL-1β, IL-6, interferon-γ, and monocyte chemoattractant protein 1 concentrations were variable in AS and undetectable in UCS. The corneal median ulcerative area was 37.2 mm² (6.28–57.14 mm²) and had a duration of 4–186 days (median 19 days). All lesions healed within 13–42 days (median 17 days). No adverse effects nor recurrences within 1 month were noticed.

Limitations

The sample size was small. Spontaneous corneal epithelial defects presented with variable clinical characteristics. There were no age-matched control horses to assess corneal healing time and rate.

Conclusion and Clinical Significance

Equine UCS may be beneficial, as it contains no pro-inflammatory cytokines and a greater concentration of TGF-β1 compared with AS. Topical UCS appears safe and may potentially be used as adjunctive therapy for equine complex non-healing ulcers.

Incidence, prevalence, and outcome of moderate to severe neurotrophic keratopathy in a German tertiary referral center from 2013 to 2017

Background

Neurotrophic keratopathy (NK) is an orphan disease, with an estimated prevalence of 1–5/10,000. No data regarding the incidence exists. The primary aim was to evaluate incidence and prevalence of NK at a tertiary referral center in Germany, and the secondary aim was to analyze demographic parameters, etiology, and clinical features and therapeutic outcomes.

Methods and material

All patients treated for NK with serum eye drops (SED), amnionic membrane transplantation (AMT), or penetrating keratoplasty (PK) in 2013–2017 were identified. Age, sex, etiology of NK, visual acuity, disease stage, treatment, and visual acuity were analyzed. Incidence and prevalence of NK in our hospital and the overall population of the city were calculated.

Results

In 63 eyes of 60 patients (56.7% male; 68 ± 16 years), the most common underlying diseases were herpetic infections (23.8%), neurological causes (19%), and diabetes mellitus (14.3%). The annual incidence of NK in our tertiary referral center ranges between 5/10,000 and 3/10,000, the prevalence between 9/10,00 and 22/10,000. In all patients treated with corneal ulcers, the prevalence was up to 27% (2706/10,000). The incidence in the overall population is estimated at 0.1–0.3/10,000, the prevalence at 0.2–0.5/10,000 to 0.5/10,000.

Conclusion

Based on our assessment, the prevalence of NK in the overall population is lower than estimated before. However, in patients with corneal ulcers, the percentage of NK is comparably high. The disease may still be underdiagnosed due to the variety of underlying disorders and unknown comorbidities. Thus, in cases of therapy-refractive superficial keratopathy or ulcerations, NK should be considered more frequently.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05535-z.

Effects of Amniotic Membrane Extract Eye Drops on Persistent Epithelial Defects of the Cornea

Purpose: To evaluate the clinical efficacy of amniotic membrane extract eye drops (AMEEDs) in patients with persistent epithelial defects (PEDs) of the cornea.Methods: Sixteen patients with PEDs refractory to the conventional treatment were further treated with AMEEDs six times a day. Visual acuity, visual analog scale (VAS), esthesiometer score, and areas of the epithelial defects before and after 1 and 2 months of treatment were evaluated. After 2 months, AMEEDs were considered effective if all epithelial defects were healed, partially effective if the epithelial defects decreased in size compared with the baseline, and ineffective if the epithelial defects increased in size and required additional treatment.Results: After 2 months of treatment with AMEEDs, there was a reduction in the area of epithelial defects (5.2 ± 3.1 mm2 vs. 0.1 ± 0.1 mm2, respectively, p = 0.01), as well as a significant improvement in best-corrected visual acuity (0.8 ± 0.5 logarithm of minimal angle of resolution [LogMAR] vs. 0.6 ± 0.3 LogMAR, respectively, p = 0.03), and VAS scores (4.3 ± 1.0 vs. 2.8 ± 0.7, respectively, p = 0.04) compared with the baseline values. Treatment with AMEEDs was effective in 13 (81.3%) patients and partially effective in three (18.8%) patients.Conclusions: AMEEDs could stimulate epithelial wound healing and improve ocular symptoms in patients with refractory PED. Therefore, AMEEDs could be considered an effective treatment option for refractory PEDs.

Expert consensus on the identification, diagnosis, and treatment of neurotrophic keratopathy

Background

Neurotrophic keratopathy (NK) is a relatively uncommon, underdiagnosed degenerative corneal disease that is caused by damage to the ophthalmic branch of the trigeminal nerve by conditions such as herpes simplex or zoster keratitis, intracranial space-occupying lesions, diabetes, or neurosurgical procedures. Over time, epithelial breakdown, corneal ulceration, corneal melting (thinning), perforation, and loss of vision may occur. The best opportunity to reverse ocular surface damage is in the earliest stage of NK. However, patients typically experience few symptoms and diagnosis is often delayed. Increased awareness of the causes of NK, consensus on when and how to screen for NK, and recommendations for how to treat NK are needed.

Methods

An 11-member expert panel used a validated methodology (a RAND/UCLA modified Delphi panel) to develop consensus on when to screen for and how best to diagnose and treat NK. Clinicians reviewed literature on the diagnosis and management of NK then rated a detailed set of 735 scenarios. In 646 scenarios, panelists rated whether a test of corneal sensitivity was warranted; in 20 scenarios, they considered the adequacy of specific tests and examinations to diagnose and stage NK; and in 69 scenarios, they rated the appropriateness of treatments for NK. Panelist ratings were used to develop clinical recommendations.

Results

There was agreement on 94% of scenarios. Based on this consensus, we present distinct circumstances when we strongly recommend or may consider a test for corneal sensitivity. We also present recommendations on the diagnostic tests to be performed in patients in whom NK is suspected and treatment options for NK.

Conclusions

These expert recommendations should be validated with clinical data. The recommendations represent the consensus of experts, are informed by published literature and experience, and may improve outcomes by helping improve diagnosis and treatment of patients with NK.

Regenerative Therapy Using Umbilical Cord Serum

Regenerative medicine is a branch of medicine that incorporates tissue-engineering, biomaterials, and cell therapy approaches to replace or repair damaged cells and tissues. Umbilical cord serum (UCS) is an important liquid component of cord blood, which has a reliable source of innumerable growth factors and biologically active molecules. Usually, serum can be prepared from different sources of blood. In therapeutic application, cord serum can be prepared and used in the form of eye drops for the treatment of severe dry eye diseases, ocular burns, glaucoma, persistent corneal epithelial defects and neurotrophic keratitis. In addition, cord serum combined with synthetic bio scaffold materials is used to regenerate different types of tissues including tympanic membrane regeneration, bone regeneration and nerve regeneration. Absence of animal origin viruses and bacteria, lack of xenoproteins and cost-effective features make cord serum a feasible choice as replacement of fetal bovine serum in cell culture techniques. Thus, this review emphasizes the role of cord serum in regenerative therapy and clinical uses.

Bioprinted collagen-based cell-laden scaffold with growth factors for tympanic membrane regeneration in chronic perforation model

With the recent development of bioprinting technology, various attempts have been made to replace bioprinting technologies and regenerative medicine are more directed towards transplantation/reconstructive surgeries only with the implantation of scaffolds. The purpose of this study is to determine whether the growth factors, human umbilical cord serum (hUCS) and bFGF (basic fibroblast growth factor), have a synergistic effect on eardrum regeneration, when used with a cell-printed scaffold in a chronic tympanic membrane perforation (TMP) model. In this study, in vitro cellular activities for bioprinted cell-laden collagen scaffolds using human adipose stem cells (hASCs) and supplemented with 10 μg/mL hUCS and 10 ng/mL bFGF were performed. The mixture of the growth factors in the cell-laden structures effectively affects various in vitro cellular responses including the proliferation of hASCs and the migration of keratinocytes due to the synergistic effect of the growth factors and hASCs. For the in vivo evaluation, a rat TMP model was used, and the TMP regeneration was assessed by otoscopic examination, hearing threshold measurement, and histologic examination. Although the cell-laden structure containing hUCS was more enhancing effect compared to the structure with bFGF, more synergistic effect in the structure using hUCS/bFGF was observed. Based on the results, we believe that the cell-laden structure incorporating hUCS and bFGF can induce significant regeneration of chronic tympanic membrane perforation.

Current and future therapies for persistent corneal epithelial defects and neurotrophic keratopathy

PURPOSE OF REVIEW

The corneal epithelium is a crucial barrier against pathogens, and when disrupted in the setting of certain underlying risk factors such as neurotrophic keratopathy (NK), may result in persistent epithelial defects (PEDs) of the cornea. Management is challenging and may require a variety of different approaches ranging from conservative medical therapy to surgical intervention. The purpose of this review is to provide an update on current and potential future therapeutic options for PEDs and NK.

RECENT FINDINGS

Recent research has yielded promising results for numerous novel therapies aimed at treating PEDs. Many of these attempt to stimulate healing at the cellular level, via signaling of corneal epithelial differentiation, migration, and proliferation. Considerable advances have also been made regarding medical and surgical promotion of corneal re-innervation and restoration of corneal sensitivity to directly address the underlying NK condition.

SUMMARY

Together with the current well established therapeutic options available for PEDs and NK, growing research on newer alternatives suggest increasing potential for both more effective and more convenient therapies for these difficult situations.

Use of Acellular Umbilical Cord-Derived Tissues in Corneal and Ocular Surface Diseases

Blood derived products have become a valuable source of tissue for the treatment of ocular surface diseases that are refractory to conventional treatments. These can be obtained from autologous or allogeneic sources (patient’s own blood or from healthy adult donors/umbilical cord blood, respectively). Allogeneic cord blood demonstrates practical advantages over alternatives and these advantages will be discussed herein. Umbilical cord blood (UCB) can be divided, generally speaking, into two distinct products: first, mononuclear cells, which can be used in regenerative ophthalmology, and second, the plasma/serum (an acellular fraction), which may be used in the form of eyedrops administered directly to the damaged ocular surface. The rationale for using umbilical cord serum (UCS) to treat ocular surface diseases such as severe dry eye syndrome (DES), persistent epithelial defects (PED), recurrent epithelial erosions, ocular chemical burns, graft versus host disease (GVHD), among others, is the considerably high concentration of growth factors and cytokines, mimicking the natural healing properties of human tears. Allogeneic serum also offers the opportunity for therapeutic treatment to patients who, due to poor heath, cannot provide autologous serum. The mechanism of action involves the stimulation of endogenous cellular proliferation, differentiation and maturation, which is highly efficient in promoting and enhancing corneal epithelial healing where other therapies have previously failed.

Therapeutic measures for sulfur mustard-induced ocular injury

The use of sulfur mustard (SM) in global terrorism is still a relevant threat to both civilian population and military personnel. Casualties exposed to SM may present mild, moderate or severe acute ocular lesions followed by a complete ocular resolution, chronic lesions or re-emerged ocular pathologies after a latent period. Current treatment for SM-induced ocular injury is based mainly on the clinical manifestation at the different stages of the injury and includes pharmaceutical and surgical interventions. These therapeutic measures are beneficial but not sufficient, and the ocular injury remains a continuous challenge for medical professionals. This review focuses on treatment experience carried out in humans and studied in animal models, for both SM-induced ocular acute injury and late pathology. In general, therapeutic measures are based on clinical features of the ocular injury or on the involvement of specific factors during the ocular injury that point out towards potential treatments. Anti-inflammatory treatments and limbal stem cell transplantation techniques were developed based on the clinical manifestation of the ocular injury. Optional therapies for impaired corneal innervation and endothelium are suggested for future research. Additionally, studies on potential treatments with anti-matrix metalloproteinase (MMP), anti-vascular endothelial growth factor (VEGF) and anti-IL-6 agents are discussed. Consequently, future studies may reveal the potential of additional pharmacological and biological treatments or advanced cellular and molecular biology methods to serve as novel therapeutic measures and techniques for this complicated ocular injury.

Corneal epithelium tissue engineering: recent advances in regeneration and replacement of corneal surface

Currently, many corneal diseases are treated by corneal transplantation, artificial corneal implantation or, in severe cases, keratoprosthesis. Owing to the shortage of cornea donors and the risks involved with artificial corneal implants, such as infection transmission, researchers continually seek new approaches for corneal regeneration. Corneal tissue engineering is a promising approach that has attracted much attention from researchers and is focused on regenerative strategies using various biomaterials in combination with different cell types. These constructs should have the ability to mimic the native tissue microenvironment and present suitable optical, mechanical and biological properties. In this article, we review studies that have focused on the current clinical techniques for corneal replacement. We also describe tissue-engineering and cell-based approaches for corneal regeneration.

Clinical evaluation of allogeneic eye drops from cord blood platelet lysate

BACKGROUND

Current treatments for several corneal lesions show limited efficacy. Here we report the clinical evaluation of the efficacy of a novel eye drop preparation produced in a public cord blood (CB) bank.

MATERIAL AND METHODS

In a multicentre, retrospective, consecutive case study we evaluated 33 patients (46 eyes) unresponsive to conventional treatments who required urgent intervention. The patients were given allogeneic eye drops obtained from cord blood platelet lysate (CBED) to treat severe ocular surface lesions under a compassionate use protocol. The CBED were prepared from CB units donated for haematopoietic stem cell transplantation that did not contain the minimum stem cell dose required for this use. Patients were grouped by acute conditions (neurotrophic ulcers: group I; other corneal ulcers: group II; corneal burns: group III), and chronic conditions (ocular graft-versus-host disease: group IV; severe dry eye syndrome: group V). The patients received one or two drops of the product to the affected eye four to six times per day for 19 days. A further 19-day cycle of treatment could be repeated according to the initial clinical response.

RESULTS

Patients received a median of 19 CBED vials (interquartile range 19-57, range 19-442) to complete the therapy. Group I-II-III patients showed full and partial ulcer recovery in 25 (78%) and six (19%) eyes respectively. One eye (3%) did not respond to treatment. For groups IV-V improvement was reported for 12 (85%) eyes and lesions worsened on treatment in both eyes (15%) of one patient. No severe adverse events were directly attributed to CBED.

DISCUSSION

Promptly available CBED resulted in a well-tolerated allogeneic treatment that showed evidence of efficacy in this cohort of patients. These positive results support further studies on CBED from platelet lysate as a novel product of CB banks. A prospective clinical trial in neurotrophic keratitis (NCT03084861) is ongoing to confirm these preliminary data.

Corneal Neurotization and Novel Medical Therapies for Neurotrophic Keratopathy

Purpose of Review

Neurotrophic keratopathy (NK) is a degenerative corneal disease characterized by decreased corneal sensibility and impaired corneal healing. In this article, we review surgical techniques for corneal neurotization (CN) and novel medical therapies for the treatment of NK.

Recent Findings

In recent decades, there has been a paradigm shift in the treatment strategies for NK. New minimally invasive direct and indirect CN approaches have demonstrated efficacy at improving best-corrected visual acuity and central corneal sensation while decreasing surgical morbidity. In addition, several targeted medical therapies, such as recombinant human nerve growth factor (rhNGF), regenerating agents (RGTA), and nicergoline, have shown promise in improving corneal epithelial healing. Of these options, cenegermin (Oxervate®, Dompé), a topical biologic medication, has emerged as an approved medical treatment for moderate to severe NK.

Summary

NK is a challenging condition caused by alterations in corneal nerves, leading to impairment in sensory and trophic function with subsequent breakdown of the cornea. Conventional therapy for NK depends on the severity of disease and focuses primarily on protecting the ocular surface. In recent years, numerous CN techniques and novel medical treatments have been developed that aim to restore proper corneal innervation and promote ocular surface healing. Further studies are needed to better understand the long-term efficacy of these treatment options, their target populations, and the potential synergistic efficacy of combined medical and surgical treatments.

Umbilical cord blood: Current uses for transfusion and regenerative medicine

The past 20 years of experience with umbilical cord blood transplantation have demonstrated that cord blood is effective in the treatment of a spectrum of diseases, including hematological malignancies, bone marrow failure, hemoglobinopathies, and inborn errors of metabolism. However, only a few number of umbilical cord blood units collected have a cell content adequate for an allogenic hematopoietic stem cell transplantation. In the meanwhile, there is an increasing interest in exploiting cord blood derivatives in different fields. In this review, we will summarize the most recent updates on clinical applications of umbilical cord blood platelet derivatives for regenerative medicine, and we will revise the literature concerning the use of umbilical cord blood for autologous or allogeneic transfusion purposes. The methodological aspect and the biological characteristics of these products also will be discussed.

Management Strategies of Ocular Chemical Burns: Current Perspectives

Ocular chemical burns are absolute ophthalmic emergencies and require immediate management to minimize devastating sequelae. Management of alkali and acid burns is started at the scene of the accident by copious irrigation. Treatment is directed at improving epithelial integrity and stromal stability, reduction of undue inflammation, and prevention or timely management of complications. To ascertain the best possible outcome, numerous biological medications and surgical interventions have been merged into conventional therapeutic regimens. These include autologous and umbilical cord serum preparations, platelet-rich plasma, amniotic membrane transplantation, limbal stem-cell transplantation, and anti-angiogenic agents.

Effect of epidermal growth factor ointment on persistent epithelial defects of the cornea

Background

Healthy corneal epithelium acts as a barrier against damage to the deeper structures in the eye. Failure in the mechanisms of corneal epithelization can lead to persistent epithelial defects of the cornea (PEDs) and can compromise its function. Epidermal growth factor (EGF) promotes the proliferation, migration, and differentiation of epithelial cells, endothelial cells, and fibroblasts during wound healing and may be beneficial in treating patients with PEDs. We, therefore, investigated the effect of EGF ointment on patients with PEDs.

Methods

Fifteen patients with PEDs refractory to conventional treatment were treated twice a day with EGF ointment. Patient demographics and comorbidities were noted. The epithelial healing time was determined along with the primary outcome measures in the areas of the epithelial defects, visual acuity, visual analog scale (VAS) scores, and esthesiometer scores 1 month and 2 months after treatment.

Results

Five eyes of herpetic keratitis (33.3%), 3 eyes of dry eye disease (20.0%), 3 eyes of bacterial keratitis (20.0%), 2 eyes of limbal stem cell deficiency (13.3%), 1 eye of diabetic neurotrophic keratitis (6.7%), and 1 eye of filamentary keratitis (6.7%) were associated with PEDs, respectively. Two months following treatment with EGF ointment, there was a reduction in the area of the epithelial defects (5.7 ± 3.9 to 0.1 ± 0.3 mm²) as well as a significant improvement in best-corrected visual acuity (0.9 ± 0.8 to 0.6 ± 0.5 LogMAR) and VAS scores (4.5 ± 1.2 to 2.5 ± 0.7) in 12 eyes (80%). Among these cases, the mean epithelial healing time was 5.5 ± 1.8 weeks. Amniotic membrane transplantation was performed on the remaining 3 (20.0%) patients that did not respond to EGF treatment.

Conclusions

EGF ointment could reduce symptoms and promotes corneal epithelialization of refractory PEDs. It may, therefore, be well-tolerated and a potentially beneficial addition in the management of refractory PEDs.

Umbilical Cord Blood and Serum for the Treatment of Ocular Diseases: A Comprehensive Review

Several blood derivatives have been proposed for the treatment of various ocular diseases that affect either the anterior or the posterior segment of the eye. Blood sources may range from the patient’s own peripheral blood (autologous) to donor tissues, mainly allogeneic peripheral blood and umbilical cord blood (UCB). The utilization of the latter permits the collection of a large amount of serum all at once, and is characterized by therapeutic feasibility in patients with a poor general condition or anemia and blood dyscrasia. Products derived from UCB have two potential uses. First, serum in the form of eye drops can be applied topically onto the ocular surface to efficiently treat anterior segment disorders such as dry eye syndrome or corneal epithelial defects with different etiologies. The rationale for and efficacy of this application derive from the high concentrations of biologically active components and growth factors in UCB, which can nourish the ocular surface. Second, UCB is a source of stem cells, which are used in the field of regenerative medicine because they differentiate into various mature cells, including corneal and retinal cells. Therefore, UCB-derived stem cells have been proposed as a replacement therapy for the treatment of retinal and optic nerve diseases, given that current standard treatments often fail. The present review explores the clinical results that have been obtained using UCB-derived products in the field of ophthalmology, as well as the current limitations of those products in this field. Furthermore, given the promising development of UCB-based therapies, possible future directions in this area are discussed.

Blood derived treatment from two allogeneic sources for severe dry eye associated to keratopathy: a multicentre randomised cross over clinical trial

AIM

To compare the efficacy of cord blood and peripheral adult donor blood serum eyedrops, controlled for growth factor content, in the treatment of severe dry eye diseases (DED) resistant to conventional therapy.

METHODS

This was a multicentre randomised, double-masked, cross-over clinical trial. Sixty patients diagnosed as severe DED, associated to persistent corneal epithelial defects were randomised and equally assigned to group A (treated with cord blood serum (CBS)) or group B (treated with PBS), eyedrops administered eight times/day for 1 month. Primary outcome was the pretreatment and post-treatment change in corneal fluorescein staining. Secondary outcomes included the pretreatment and post-treatment change in Ocular Surface Disease Index (OSDI) questionnaire and Visual Analogue Score (VAS) of subjective symptoms, Schirmer I test, tear break-up time and conjunctival staining. Patients with relapse in signs or symptoms after further 2 months switched to the remaining group for one additional month. Data were statistically analysed (p<0.05).

RESULTS

Corneal staining was more significantly reduced after the CBS treatment, both VAS and OSDI score reduction was observed in both groups, but group A reported significantly less grittiness and pain. Nineteen patients shifted in the crossover period, the within individual comparison confirmed a better recovery in the CBS treatment period. Reduction in epithelial damage was positively associated with epidermal growth factor, transforming growth factorα and platelet-derived growth factor content. Levels of interleukins (IL-13) were positively associated with symptom decrease.

CONCLUSIONS

Overall, DED signs improved after both CBS and PBS treatments, with potential advantages of CBS for subjective symptoms and corneal damage reduction.

CLINICAL TRIAL REGISTRATION

NCT03064984.

Blood-Based Treatments for Severe Dry Eye Disease: The Need of a Consensus

The use of blood-based eye drops as therapy for various diseases of the ocular surface has become increasingly popular in ophthalmic practice during recent years. The rationale for their use is based on the promotion of cellular proliferation and migration thanks to the supply of metabolically active substances, in particular growth factors. Blood-derived eye drops have been used for the treatment of several ocular surface disorders, such as dry eye disease, corneal ulcer, persistent epithelial defect, neurotrophic keratitis, ocular surface burn, recurrent corneal erosion, and limbal stem-cell deficiency. Both autologous (from patients themselves) and heterologous (from adult donors or from cord blood sampled at birth)-derived products exist, and each source has specific pros and cons. Despite an extensive literature, several issues are still under debate and the aim of this manuscript is to review the indications, preparation methods and storage, characterization of content, rationale for clinical outcomes, patient stratification, length of treatment, and rationale for repeated treatments at disease relapse. A rationale based on a "5 Ws and 2 Hs" protocol is proposed as a way of thinking, with the attempt to clarify Who, Why, When, Where, What, and How to use these treatment options.

Therapeutic effects of three human-derived materials in a mouse corneal alkali burn model

Purpose: To compare the therapeutic effects of human derivatives in a mouse alkali burn model. Methods: The right eyes of mice were injured using NaOH. After alkali injury, one of the following agents was topically administered for 7 d: human amniotic membrane (hAM) suspension, human umbilical cord serum (hUCS), and human peripheral blood serum (hPBS), or saline. The epithelial defect areas on days 1, 2, and 3 degrees of opacity on days 2, 3, and 7, and corneal neovascularization (NV) areas on day 7 were evaluated. Histologic examination and mRNA expression levels of tumour necrosis factor (TNF)-α, interleukin (IL)-6, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, MMP-8, and MMP-9 were also evaluated on day 7. Results: The epithelial defect areas in the hUCS group were smaller than those in the control and hPBS groups on day 3 (p < .05, respectively). The epithelial defect areas in the hAM suspension group showed smaller than those in the control and hPBS groups on days 1 and 2 (p < .05, respectively). The degrees of opacity were lower in all treatment groups than that of the saline control group on day 7 (p < .05, respectively). Corneal NV areas were not different among groups on day 7 (p = 0.20). The expression levels of TNF-α, IL-6, MMP-8, and MMP-9 mRNA and the infiltration of the inflammatory cells in all treatment groups were lesser than those in the control group on day 7 (p< .05, respectively). Conclusions: All treatments reduced inflammatory reactions and corneal opacity development. Corneal reepithelialization was faster in the hUCS group.

Post-herpes neurotrophic keratopathy: Aetiopathogenesis, clinical signs and current therapies

Neurotrophic keratopathy (NK) is a degenerative corneal disease caused by damage of trigeminal innervation. This leads to epithelial defects, ulceration and, eventually, perforation. Both herpes simplex and varicella zoster keratitis are reported to be the main causes of NK. Furthermore, prognosis in this type of NK is poor. Classic clinical findings in post-herpes NK are spontaneous epithelial breakdown, round and central epithelial defects with smooth edges, stromal melting and thinning, scarring, and neovascularisation. Although several medical and surgical treatments have been reported, no therapies are currently available to definitely restore corneal sensitivity. Therefore, NK remains a challenging disease to treat. In this review a summary is presented of the pathogenesis, manifestations, and current management of post-herpes NK. The role of antiviral treatment and varicella-zoster vaccination is also discussed. A description is also presented on both medical and surgical novel therapies, such as regenerative drugs and corneal neurotization.

Effect of D-Panthenol on Corneal Epithelial Healing after Surface Laser Ablation

Purpose

To study the effect of D-panthenol (provitamin B5) on corneal epithelial healing, in cases of surface laser ablation. Patients and Methods: 45 eyes, of 45 patients undergoing laser surface ablation, received D-panthenol 2% in one eye and artificial tear drops of similar composition not containing D-panthenol in the other eye, postoperatively, for 2 months. Patients were examined daily for 3 days after the procedure. They were then examined weekly for 1 month. An additional examination was made after 2 months. Visual acuity (Log MAR) was assessed at every visit. Rate of healing (% of covered area) and subjective sensation of discomfort (scale 0–5) were assessed in the 1st 3 visits. Residual manifest cylinder (D) (as a parameter of corneal irregularity) and corneal clarity (epithelial and stromal haze) were assessed from week 1 to month 2.

Results

During the first 3 days, both groups showed statistically nonsignificant (P > 0.05) results. From week 1 to month 2, eyes receiving D-panthenol showed better vision and less residual cylinder (P < 0.05) at week 1. For all other parameters, and at different examinations, both groups showed a statistically nonsignificant (P > 0.05) difference. Still, eyes receiving D-panthenol showed better values at the majority of the parameters tested.

Conclusion

D-Panthenol effect on corneal epithelial regeneration is of minimal clinical relevance. A different dosage and a larger sample of patients might reveal a statistical relevance. This trial is registered with https://doi.org/10.1186/ISRCTN81441126.

Plasma derived from human umbilical cord blood: Potential cell-additive or cell-substitute therapeutic for neurodegenerative diseases

Limited efficacy of current therapeutic approaches for neurodegenerative disease has led to increased interest in alternative therapies. Cord blood plasma (CBP) derived from human umbilical cord blood (hUCB) may be a potential therapeutic. Benefits of CBP injection into rodent models of aging or ischaemic stroke have been demonstrated, though how benefits are elicited is still unclear. The present study evaluated various factors within the same samples of CBP and human adult blood plasma/sera (ABP/S). Also, autologous CBP effects vs. ABP/S or foetal bovine serum supplements on mononuclear cells from hUCB (MNC hUCB) in vitro were determined. Results showed significantly low concentrations of pro-inflammatory cytokines (IL-2, IL-6, IFN-γ, and TNF-α) and elevated chemokine IL-8 in CBP. Significantly higher levels of VEGF, G-CSF, EGF and FGF-basic growth factors were determined in CBP vs. ABP/S. Autologous CBP media supplements significantly increased MNC hUCB viability and decreased apoptotic cell activity. We are first to demonstrate the unique CBP composition of cytokines and growth factors within the same CBP samples derived from hUCB. Also, our novel finding that autologous CBP promoted MNC hUCB viability and reduced apoptotic cell death in vitro supports CBP's potential as a sole therapeutic or cell-additive agent in developing therapies for various neurodegenerative diseases.

Neurotrophic keratitis: current challenges and future prospects

Neurotrophic keratitis (NK) is a degenerative corneal disease caused by damage of trigeminal corneal innervation, which leads to spontaneous epithelial breakdown and corneal ulceration. The impairment of corneal sensory innervation causes the reduction of both protective reflexes and trophic neuromodulators that are essential for the vitality, metabolism, and wound healing of ocular surface tissues. A wide range of ocular and systemic conditions, including herpetic keratitis, ocular chemical burns, corneal surgery, diabetes, multiple sclerosis, and neurosurgical procedures, can cause NK by damaging trigeminal innervation. Diagnosis of NK requires careful investigation of any ocular and systemic condition associated with the disease, complete ocular surface examination, and quantitative measurement of corneal sensitivity. The clinical stages of NK range from corneal epithelial alterations (stage 1) to persistent epithelial defect (stage 2) and ulcer (stage 3), which may progress to corneal perforation. Management of NK is based on clinical severity, and the aim of the therapy is to halt the progression of corneal damage and promote epithelial healing. Although several medical and surgical treatments have been proposed, no therapies are currently available to restore corneal sensitivity, and thus, NK remains difficult and challenging to treat. The purpose of this review is to summarize available evidence on the pathogenesis, diagnosis, and treatment of NK. Novel medical and surgical therapies including the topical administration of nerve growth factor and corneal neurotization are also described.

Application of Novel Drugs for Corneal Cell Regeneration

Corneal transplantation has been the only treatment method for corneal blindness, which is the major cause of reversible blindness. However, despite the advancement of surgical techniques for corneal transplantation, demand for the surgery can never be met due to a global shortage of donor cornea. The development of bioengineering and pharmaceutical technology provided us with novel drugs and biomaterials that can be used for innovative treatment methods for corneal diseases. In this review, the authors will discuss the efficacy and safety of pharmacologic therapies, such as Rho-kinase (ROCK) inhibitors, blood-derived products, growth factors, and regenerating agent on corneal cell regeneration. The promising results of these agents suggest that these can be viable options for corneal reconstruction and visual rehabilitation.

Effects of subtenon-injected autologous platelet-rich plasma on visual functions in eyes with retinitis pigmentosa: preliminary clinical results

PURPOSE

One of the main reasons for apoptosis and dormant cell phases in degenerative retinal diseases such as retinitis pigmentosa (RP) is growth factor withdrawal in the cellular microenvironment. Growth factors and neurotrophins can significantly slow down retinal degeneration and cell death in animal models. One possible source of autologous growth factors is platelet-rich plasma. The purpose of this study was to determine if subtenon injections of autologous platelet-rich plasma (aPRP) can have beneficial effects on visual function in RP patients by reactivating dormant photoreceptors.

MATERIAL AND METHODS

This prospective open-label clinical trial, conducted between September 2016 and February 2017, involved 71 eyes belonging to 48 RP patients with various degrees of narrowed visual field. Forty-nine eyes belonging to 37 patients were injected with aPRP. A comparison group was made up of 11 patients who had symmetrical bilateral narrowed visual field (VF) of both eyes. Among these 11 patients, one eye was injected with aPRP, while the other eye was injected with autologous platelet-poor plasma (aPPP) to serve as a control. The total duration of the study was 9 weeks: the aPRP or aPPP subtenon injections were applied three times, with 3-week intervals between injections, and the patients were followed for three more weeks after the third injection. Visual acuity (VA) tests were conducted on all patients, and VF, microperimetry (MP), and multifocal electroretinography (mfERG) tests were conducted on suitable patients to evaluate the visual function changes before and after the aPRP or aPPP injections.

RESULTS

The best-corrected visual acuity values in the ETDRS chart improved by 11.6 letters (from 70 to 81.6 letters) in 19 of 48 eyes following aPRP application; this result, however, was not statistically significant (p = 0.056). Following aPRP injections in 48 eyes, the mean deviation of the VF values improved from - 25.3 to - 23.1 dB (p = 0.0001). Results regarding the mfERG P1 amplitudes improved in ring 1 from 24.4 to 38.5 nv/deg² (p = 0.0001), in ring 2 from 6.7 to 9.3 nv/deg² (p = 0.0301), and in ring 3 from 3.5 to 4.5 nv/deg² (p = 0.0329). The mfERG P1 implicit times improved in ring 1 from 40.0 to 34.4 ms (p = 0.01), in ring 2 from 42.5 to 33.2 ms (p = 0.01), and in ring 3 from 42.1 to 37.9 ms (p = 0.04). The mfERG N1 amplitudes improved in ring 1 from 0.18 to 0.25 nv/deg² (p = 0.011) and in ring 2 from 0.05 to 0.08 nv/deg² (p = 0.014). The mfERG N1 implicit time also improved in ring 1 from 18.9 to 16.2 ms (p = 0.040) and in ring 2 from 20.9 to 15.5 ms (p = 0.002). No improvement was seen in the 11 control eyes into which aPPP was injected. In the 23 RP patients with macular involvement, the MP average threshold values improved with aPRP injections from 15.0 to 16.4 dB (p = 0.0001). No ocular or systemic adverse events related to the injections or aPRP were observed during the follow-up period.

CONCLUSION

Preliminary clinical results are encouraging in terms of statistically significant improvements in VF, mfERG values, and MP. The subtenon injection of aPRP seems to be a therapeutic option for treatment and might lead to positive results in the vision of RP patients. Long-term results regarding adverse events are unknown. There have not been any serious adverse events and any ophthalmic or systemic side effects for 1 year follow-up. Further studies with long-term follow-up are needed to determine the duration of efficacy and the frequency of application.

Evaluation of the Role of Umbilical Cord Serum and Autologous Serum Therapy in Reepithelialization After Keratoplasty: A Randomized Controlled Clinical Trial

PURPOSE

To evaluate the role of umbilical cord serum (UCS) and autologous serum (AS) therapy in reepithelialization of corneal graft after keratoplasty in a randomized controlled trial.

METHODS

A total of 105 eyes with epithelial defect (ED) after keratoplasty (penetrating keratoplasty-67 and anterior lamellar keratoplasty-38) on the first postoperative day were included in the study. The eyes were randomized into three groups: UCS (n=35), AS (n=35), and artificial tears (AT) (n=35). All patients received standard postoperative medical therapy. The primary outcome measure was time to epithelialization, and secondary outcome measures were best-corrected visual acuity and graft clarity.

RESULTS

The ED healed completely in 103 eyes. The mean time for complete reepithelialization was 2.5±2.1, 3.1±2.2, and 4.5±1.4 days in UCS, AS, and AT groups, respectively. The mean percentage decrease in the size of the ED was significantly better in the UCS and AS groups as compared with the AT group (P=0.001). The rate of reepithelialization was comparable between the AS and UCS groups (P=0.3). On bivariate analysis, significant correlation was found between the mean size of postoperative ED, grade of the donor cornea (P=0.001), and the presence of preoperative ED (P=0.001). No complications were associated with the use of serum therapy.

CONCLUSION

Most of the cases of postkeratoplasty corneal ED can be managed with AT only. The serum therapy (AS/UCS) helps in the faster reepithelialization of postkeratoplasty ED as compared with AT and may be considered as a treatment option for early epithelial healing.

Corneal nerve regeneration after herpes simplex keratitis: A longitudinal in vivo confocal microscopy study

PURPOSE

To evaluate the long-term alterations of corneal nerves in patients with herpes simplex virus (HSV) keratitis using in vivo confocal microscopy (IVCM).

DESIGN

Prospective, longitudinal, cross sectional.

METHODS

This study included 16 patients with a history of HSV keratitis and 15 age-matched normal controls. Slit-scanning IVCM was performed in all subjects at baseline and then after a mean follow-up of 37.3 ± 1.7 months in the patient group. Corneal subbasal nerve density and corneal sensation were compared between groups at baseline and follow-up.

RESULTS

At baseline, the mean subbasal nerve density was significantly lower in both affected eyes (1.4 ± 0.6 mm/mm²) and contralateral unaffected eyes (6.4 ± 0.7 mm/mm²) compared with the controls (14.1 ± 1.6 mm/mm²; all P < .001). At the end of follow-up, the mean nerve density in affected eyes increased to 2.8 ± 0.7 mm/mm² (P = .006), with no significant change in contralateral unaffected eyes (6.5 ± 1.0 mm/mm², P = .72). However, both eyes had lower nerve density than controls (all P < .001). Corneal sensation was significantly lower in affected eyes (2.6 ± 0.6 cm) than in the control group (6.0 ± 0.0, P < .001) and showed no significant change at the end of follow-up (2.5 ± 0.6 cm, P = .80). Corneal sensation in contralateral unaffected eyes was not different in comparison with controls at both baseline and follow up (all p > .05).

CONCLUSIONS

Our results demonstrate that although corneal nerve regeneration occurs in patients with HSV keratitis, this change is not clinically significant and does not results in changes of corneal sensation. Therefore, these patients need to be followed closely for complications of neurotrophic keratopathy and might benefit from neuro-regenerative therapies.

Treatment of acute ocular chemical burns

Ocular chemical burns are an ophthalmic emergency and are responsible for 11.5%-22.1% of ocular injuries. Immediate copious irrigation is universally recommended in acute ocular burns to remove the offending agent and minimize damage. Conventional medical therapy consists of the use of agents that promote epithelialization, minimize inflammation, and prevent cicatricial complications. Biological fluids such as autologous serum, umbilical cord blood serum, platelet-rich plasma, and amniotic membrane suspension are a rich source of growth factors and promote healing when used as adjuncts to conventional therapy. Surgical treatment of acute ocular burns includes the debridement of the necrotic tissue, application of tissue adhesives, tenoplasty, and tectonic keratoplasty. Amniotic membrane transplantation is a novel surgical treatment that is increasingly being used as an adjunct to conventional treatment to promote epithelial healing, minimize pain, and restore visual acuity. Various experimental treatments that aim to promote wound healing and minimize inflammation are being evaluated such as human mesenchymal and adipose stem cells, beta-1,3 glucan, angiotensin-converting enzyme inhibitors, cultivated fibroblasts, zinc desferrioxamine, antifibrinolytic agents, antioxidants, collagen cross-linking, and inhibitors of corneal neovascularization.