Autologous serum eye drops for the treatment of ocular surface disease

Serum-derived extracellular vesicles for the treatment of severe ocular surface disease

PURPOSE

Autologous serum is widely used for the treatment of severe ocular surface disease with mixed efficacy. Extracellular vesicles (EVs) are small membrane bound structures present in all body fluids, including serum. This study compared the proteomic, metabolomic, and inflammatory cytokine composition of serum-derived EVs (SDEVs) to that of the soluble free protein fraction and the subsequent capacity of SDEVs to induce corneal epithelial cell migration and inflammation.

METHODS

SDEVs were isolated from human serum using size exclusion chromatography. SDEVs were analyzed using nanoparticle tracking analysis, transmission electron microscopy, and western blotting. The effects of SDEVs on corneal epithelial cell migration were tested using a standard scratch assay. Inflammatory cytokines in SDEVs and the free protein fraction were quantified using a microarray. A mutli-omics approach was further used to define SDEV cargo. The ability of SDEVs to modulate inflammation in corneal epithelial cells was quantified using ELISAs.

RESULTS

Western blot and TEM confirmed the presence of SDEVs. Proinflammatory cytokines, along with complement proteins and TGF-β, were decreased in SDEVs compared to serum. Metabolites present in SDEVs were mostly involved in amino acid biosynthesis, the TCA cycle and oxidative phosphorylation. SDEVs exhibited pro-migratory effects similar to serum however, SDEVs did not induce secretion of IL-6 or IL-8.

CONCLUSIONS

SDEVs exhibit reduced levels of pro-inflammatory cytokines while retaining the beneficial wound healing properties of serum. Unlike serum, SDEVs do not induce inflammation. SDEVs may represent an alternative option for patients with severe ocular surface disease where traditional autologous serum has failed.

Immunophenotypical Characterization of Limbal Mesenchymal Stromal Cell Subsets during In Vitro Expansion

Limbal mesenchymal stromal cells (LMSCs) reside in the limbal niche, supporting corneal integrity and facilitating regeneration. While mesenchymal stem/stromal cells (MSCs) are used in regenerative therapies, there is limited knowledge about LMSC subpopulations and their characteristics. This study characterized human LMSC subpopulations through the flow cytometric assessment of fifteen cell surface markers, including MSC, wound healing, immune regulation, ASC, endothelial, and differentiation markers. Primary LMSCs were established from remnant human corneal transplant specimens and passaged eight times to observe changes during subculture. The results showed the consistent expression of typical MSC markers and distinct subpopulations with the passage-dependent expression of wound healing, immune regulation, and differentiation markers. High CD166 and CD248 expressions indicated a crucial role in ocular surface repair. CD29 expression suggested an immunoregulatory role. Comparable pigment-epithelial-derived factor (PEDF) expression supported anti-inflammatory and anti-angiogenic roles. Sustained CD201 expression indicated maintained differentiation capability, while VEGFR2 expression suggested potential endothelial differentiation. LMSCs showed higher VEGF expression than fibroblasts and endothelial cells, suggesting a potential contribution to ocular surface regeneration through the modulation of angiogenesis and inflammation. These findings highlight the heterogeneity and multipotent potential of LMSC subpopulations during in vitro expansion, informing the development of standardized protocols for regenerative therapies and improving treatments for ocular surface disorders.

Corneal neuropathic pain: a review to inform clinical practice

Corneal neuropathic pain (CNP) is a poorly defined disease entity characterised by an aberrant pain response to normally non-painful stimuli and categorised into having peripheral and central mechanisms, with the former responding to instillation of topical anaesthetic. CNP is a challenging condition to diagnose due to numerous aetiologies, an absence of clinical signs and ancillary tests (in vivo confocal microscopy and esthesiometry), lacking the ability to confirm the diagnosis and having limited availability. Symptomatology maybe mirrored by severe and chronic forms of dry eye disease (DED), often leading to misdiagnosis and inadequate treatment. In practice, patients with suspected CNP can be assessed with questionnaires to elicit symptoms. A thorough ocular assessment is also performed to exclude any co-existent ocular conditions. A medical and mental health history should be sought due to associations with autoimmune disease, chronic pain syndromes, anxiety and depression. Management begins with communicating to the patient the nature of their condition. Ophthalmologists can prescribe topical therapies such as autologous serum eyedrops to optimise the ocular surface and promote neural regeneration. However, a multi-disciplinary treatment approach is often required, including mental health support, particularly when there are central mechanisms. General practitioners, pain specialists, neurologists and psychologists may be needed to assist with oral and behavioural therapies. Less data is available to support the safety and efficacy of adjuvant and surgical therapies and the long-term natural history remains to be determined. Hence clinical trials and registry studies are urgently needed to fill these data gaps with the aim to improve patient care.

[Experimental evaluation of the efficacy of tissue-engineered constructs in the treatment of limbal stem cell deficiency]

Limbal stem cell deficiency (LSCD) is one of the leading factors negatively affecting the success of keratoplasty, and its treatment remains an urgent problem in ophthalmology. With the development of regenerative medicine, one of the promising approaches is the transplantation of tissue-engineered constructs from cultured limbal stem cells (LSCs) in biopolymer carriers.

PURPOSE

This study was conducted to develop an experimental model of LSCD and evaluate the effectiveness of transplantation of a tissue-engineered construct consisting of cultured cells containing a population of LSCs and a collagen carrier.

MATERIAL AND METHODS

The study was performed on 12 rabbits and included several stages. At the first stage, the physiological effects of collagen matrix implantation into the limbal zone were studied. At the second stage, tissue-engineered constructs consisting of LSCs on a collagen matrix were formed and their effect on the regeneration processes in the experimental LSCD model was analyzed. The animals were divided into 2 groups: surgical treatment (transplantation of the tissue-engineered construct) was used in the experimental group, and conservative treatment was used in the control group. Slit-lamp biomicroscopy with photo-registration, fluorescein corneal staining, optical coherence tomography of the anterior segment of the eye, and impression cytology were used to assess the results.

RESULTS

No side reactions were observed after implantation of the collagen matrix into the limbal zone. One month after surgical treatment of the LSCD model in the experimental group, complete epithelization with minor manifestations of epitheliopathy was observed. In the control group, erosion of the corneal epithelium was noted. The time of corneal epithelization in the experimental and control groups was 9.2±2.95 and 46.20±12.07 days, respectively (p=0.139). According to the data of impression cytology, in the experimental group there were no goblet cells in the central part of the cornea, which indicates the restoration of corneal type epithelial cells, in contrast to the control group.

CONCLUSION

Transplantation of a tissue-engineered construct from cultured limbal cells on a collagen membrane should be considered as a promising method for the treatment of limbal stem cell deficiency.

Randomized controlled trial on the efficacy and safety of autologous serum eye drops in dry eye syndrome

BACKGROUND

Autologous serum eye drops (ASEDs), a novel treatment derived from blood serum, have emerged as a groundbreaking solution for managing dry eye syndrome (DES). These drops have shown significant promise in relieving the distressing symptoms of DES. This study aimed to evaluate the safety and effectiveness of ASEDs compared to traditional treatments, which often prove inadequate or result in unwanted side effects, particularly in individuals with moderate-to-severe DES.

AIM

To evaluate whether ASEDs are safer and more effective than conventional artificial tears in the treatment of moderate-to-severe DES.

METHODS

This multi-centered randomized controlled trial included 240 patients with moderate-to-severe DES from three ophthalmology clinics in China. They were randomly assigned to receive either ASEDs or artificial tears for 12 wk. The primary outcome was the change in the ocular surface disease index (OSDI) score, with secondary outcomes including tear break-up time (TBUT), Schirmer I test, corneal fluorescein staining (CFS), and conjunctival impression cytology (CIC). Statistics analysis was performed using an analysis of covariance with adjustments made for baseline values.

RESULTS

Our findings revealed that both ASEDs and artificial tears significantly improved the OSDI score, TBUT, Schirmer I test, CFS, and CIC from baseline to week 12. The ASEDs group showed significantly greater improvement in all these measures than the artificial tears group (all P values < 0.05). The average difference in the OSDI score between the two cohorts was -10.3 (95% confidence interval: -13.6 to -7.0), indicating a substantial improvement in the ASEDs group. The occurrence of adverse events was comparable between cohorts, with no reports of severe adverse events.

CONCLUSION

ASEDs are more effective and safer than artificial tears for mitigating symptoms of moderate-to-severe DES. ASEDs could be an alternative/supplementary therapy for patients with DES less responsive to traditional treatments.

Pterygium combined with corneal perforation: a case report

BACKGROUND

Pterygium is a common ocular surface disease. Pterygium combined with corneal perforation is rare.

CASE PRESENTATION

A 28-year-old female patient visited our outpatient clinic due to sudden onset of blurred vision and increased tearing in her left eye. The visual acuity was 1.0 OD and intraocular pressure (IOP) of 19.5 mmHg for the right eye with no significant abnormalities found in the anterior and posterior segments. The visual acuity of her left eye was 0.06, and IOP was 6.2 mmHg. A triangular vascular membranous tissue was seen in her left eye below the nose growing into the cornea and the pupil area was not touched. Slit-lamp examination revealed a tiny round corneal perforation in 8 o'clock position of the lesion area. Hospital diagnosis was given as pterygium combined with corneal perforation. The patient was treated with levofloxacin eye drops and autologous serum-based eye drops.

CONCLUSIONS

We report a rare case of pterygium combined with corneal perforation. Perforation is a very rare complication of pterygium. This patient received proper treatment and good result was seen. This article aimed to improve clinicians' understanding of pterygium.

Highly stable fibronectin-mimetic-peptide-based supramolecular hydrogel to accelerate corneal wound healing

Without timely treatment, poor wound healing in corneal injuries can seriously impair vision and lead to blindness. Thus, it is vital to develop a therapeutic strategy to accelerate corneal re-epithelialization. The conjugation of self-assembled motifs with a fibronectin-mimetic peptide sequence (PHSRN) drastically improves the chemical stability of PHSRN against protease hydrolysis and minimally affects its biological activity to promote the migration of corneal epithelial cells. The optimized Nap-FFPHSRN self-assembled into bioactive supramolecular hydrogels increases cell motility by remolding F-actin and boosts the tight junction of the corneal epithelium by increasing the expression of zonula occludens-1 (ZO-1). An in vivo experiment showed that a Nap-FFPHSRN hydrogel provided extended precorneal retention with good ocular tolerance after topical instillation. An animal model of corneal scrape showed that a single daily dose of Nap-FFPHSRN hydrogel had a superior therapeutic effect in facilitating corneal re-epithelialization with complete morphological and architectural recovery. With a rational approach to mimic bioactive proteins, this study presents a new strategy to demonstrate the potential of peptide-based supramolecular hydrogels for use in clinical treatment of corneal injury. STATEMENT OF SIGNIFICANCE: Here we systematically investigate the self-assembly behavior and chemical stability of designed peptide amphiphiles (Nap-FPHRSN, Nap-FFPHSRN and Nap-FFFPHSRN). The introduction of self-assembled motifs (Nap-F, Nap-FF and Nap-FFF) drastically enhances the chemical stability of fibronectin-mimetic peptide (PHSRN). Moreover, topical instillation of Nap-FFPHSRN hydrogel once daily, exhibits a better in vivo effect than PHSRN and the same in vivo effect as fibronectin, both of which are instilled three times daily, for promoting full morphological and architectural recovery after corneal re-epithelialization. As a rational design of conjugating bioactive peptides with self-assembled motifs to mimic bioactive proteins, this work may lead to a new approach that improves the in vivo therapeutic effect for treating corneal injury in clinic settings.

Concise Review: Bioengineering of Limbal Stem Cell Niche

The corneal epithelium is composed of nonkeratinized stratified squamous cells and has a significant turnover rate. Limbal integrity is vital to maintain the clarity and avascularity of the cornea as well as regeneration of the corneal epithelium. Limbal epithelial stem cells (LESCs) are located in the basal epithelial layer of the limbus and preserve this homeostasis. Proper functioning of LESCs is dependent on a specific microenvironment, known as the limbal stem cell niche (LSCN). This structure is made up of various cells, an extracellular matrix (ECM), and signaling molecules. Different etiologies may damage the LSCN, leading to limbal stem cell deficiency (LSCD), which is characterized by conjunctivalization of the cornea. In this review, we first summarize the basics of the LSCN and then focus on current and emerging bioengineering strategies for LSCN restoration to combat LSCD.

Corneal stem cells niche and homeostasis impacts in regenerative medicine; concise review

The limbal stem cells niche (LSCN) is an optimal microenvironment that provides the limbal epithelial stem cells (LESCs) and strictly regulates their proliferation and differentiation. Disturbing the LSCN homeostasis can lead to limbal stem cell dysfunction (LSCD) and subsequent ocular surface aberrations, such as corneal stromal inflammation, persistent epithelial defects, corneal neovascularisation, lymphangiogenesis, corneal opacification, and conjunctivalization. As ocular surface disorders are considered the second main cause of blindness, it becomes crucial to explore different therapeutic strategies for restoring the functions of the LSCN. A major limitation of corneal transplantation is the current shortage of donor tissue to meet the requirements worldwide. In this context, it becomes mandatory to find an alternative regenerative medicine, such as using cultured limbal epithelial/stromal stem cells, inducing the production of corneal like cells by using other sources of stem cells, and using tissue engineering methods aiming to produce the three-dimensional (3D) printed cornea. Limbal epithelial stem cells have been considered the magic potion for eye treatment. Epithelial and stromal stem cells in the limbal niche hold the responsibility of replenishing the corneal epithelium. These stem cells are being used for transplantation to maintain corneal epithelial integrity and ultimately sustain optimal vision. In this review, we summarised the characteristics of the LSCN and their current and future roles in restoring corneal homeostasis in eyes with LSCD.

[Corneal regeneration: is there a place for tissues of perinatal origin?]

The article reviews the main properties of the cornea and the mechanisms of its physiological regeneration and repair in response to damage and describes the most promising methods of treatment aimed at stimulating limbal stem cells and based on the use of native tissues of perinatal origin, umbilical cord mesenchymal stromal cells, and cell-free therapeutic products.

Short-term Efficacy and Safety of Biological Tear Substitutes and Topical Secretagogues for Dry Eye Disease: A Systematic Review and Network Meta-analysis

PURPOSE

The purpose of this study was to assess short-term efficacy and safety of tear promotion eye drops (biological tear substitutes and topical secretagogues) for treating dry eye disease.

METHODS

Randomized controlled trials comparing short-term effects of biological tear substitutes or topical secretagogues versus placebo or other topical dry eye treatments in adults with dry eye disease were identified from the MEDLINE, Embase, Scopus, ClinicalTrials.gov , and World Health Organization International Clinical Trials Registry Platform databases. Pairwise meta-analysis and network meta-analysis were performed. Outcomes were ocular symptoms, ocular surface staining, tear break-up time, Schirmer test, and adverse events. The certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Thirty-nine randomized controlled trials (3693 patients) were eligible. Using artificial tears as a reference, autologous platelet lysate was the most effective treatment for lowering ocular surface disease index (unstandardized mean difference [USMD] -31.85; 95% confidence interval [CI]: -43.19 to -20.51) and platelet rich plasma showed the most reduction in corneal fluorescein staining scores (standardized mean difference -2.52; 95% CI: -3.23 to -1.82). Cord blood serum was the most effective treatment for increasing tear break-up time (USMD 2.67; 95% CI: 0.53-4.82), and eledoisin was superior to others in improving Schirmer scores (USMD 2.28; 95% CI: 0.14-4.42). Most interventions did not significantly increase ocular adverse events compared with artificial tears.

CONCLUSIONS

Biological tear substitutes, including autologous serum, autologous platelet lysate, platelet rich plasma, and cord blood serum, might be the most effective treatment among tear promotion eye drops in relieving dry eye symptoms without increasing adverse events. However, there remains uncertainty around these findings because of low/very low certainty of evidence.

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.

Clinical Outcomes of Minimally Invasive Corneal Neurotization after Cerebellopontine Angle (CPA) Neurosurgical Procedures

PURPOSE

To report 12 patients with neurotrophic keratopathy (NK) due to the trigeminal nerve injury after intracranial tumor surgeries underwent minimally invasive corneal neurotization (MICN) and evaluate the outcomes of corneal reinnervation.

METHODS

12 patients (12 eyes) with NK caused by the trigeminal nerve injury after intracranial surgeries received MICN. All the preoperative central corneal sensation (CCS) was under 5mm and MICN was performed over 6 months after the intracranial surgery. Follow-up was conducted 1 week and 1 month after the surgery, and then every 3 months. Twelve healthy age-matched participants were enrolled as controls. The indicators included corneal sensation, best-corrected visual acuity (BCVA), corneal nerve fiber length and branch density, diameter of nerve trunk, corneal ulcer lesion ratio and sensation of the contralateral forehead.

RESULTS

Mean follow-up was 24.7 ± 7.1 months. Mean CCS rose from 0.4 ± 1.4 to 31.7 ± 21.8 mm. Corneal nerve fiber length improved from 9.56 ± 5.00 to 14.96 ± 4.65 mm/mm² and corneal nerve branch density and diameter of nerve trunk both increased (p < 0.01 and p < 0.05 respectively). Corneal lesion ratio decreased from 0.17 ± 0.12 to 0.10 ± 0.10 (p < 0.01).

CONCLUSIONS

MICN promotes corneal reinnervation for patients with NK induced by the trigeminal nerve injury after intracranial surgeries. The process of corneal reinnervation after MICN often lasts over 12 months and it takes about 18 months to return to a higher level. Corneal sensation and corneal nerve fiber length are related to clinical outcomes such as corneal ulcer lesion and BCVA. The effect on the sensation of the contralateral side forehead is temporary and most patients can restore normal forehead sensation of the contralateral side.

Effect of Autologous Serum Eye Drops on Corneal Haze after Corneal Cross-linking

SIGNIFICANCE

Corneal haze remains a frequent post-operative finding in patients undergoing corneal cross-linking. It has been shown that autologous serum tears promote epithelial healing and reduce post-operative pain; however, the role in the prevention of corneal haze has not been reported.

PURPOSE

This study aimed to compare the effect of autologous serum tears versus preservative-free artificial tears on the prevention and resolution of post-cross-linking corneal haze.

METHODS

A retrospective cohort study was conducted in a sample population from one surgeon at a tertiary eye center from 2016 to 2019. Seventy-six eyes of consecutive patients who underwent cross-linking were included. Records were reviewed for corneal Scheimpflug densitometry values and maximum keratometry, epithelial healing time, and the use of either autologous serum tears or preservative-free artificial tears. Corneal densitometry values, expressed in standardized grayscale units (GSU), were recorded for the anterior 150-μm corneal stroma and in the 0.0 to 2.0 mm and 2.0 to 6.0 mm zones.

RESULTS

Forty-four eyes received autologous serum tears, whereas 32 eyes received preservative-free artificial tears. The baseline GSU of the anterior stromal 0 to 2 mm annulus and the 2 to 6 mm annulus did not significantly differ between groups (P = .50 and P = .40, respectively). There was a statistically significant increase in mean GSU for both anterior 0 to 2 mm and 2 to 6 mm zones between baseline and 1 month (P < .001) and 3 months (P < .001). When comparing the two groups, no statistically significant difference was found post-operatively between the mean GSU at 1 month for the anterior 0 to 2 mm (P = .38) nor the 2 to 6 mm zone (P = .12), or for the third month (P = .60 and P = .44, respectively).

CONCLUSIONS

Using Scheimpflug densitometry, we did not find a significant difference in the post-cross-linking corneal haze at 1 and 3 post-operative months between patients who use autologous serum tears and those who use preservative-free artificial tears.

OUP accepted manuscript

The corneal epithelium serves to protect the underlying cornea from the external environment and is essential for corneal transparency and optimal visual function. Regeneration of this epithelium is dependent on a population of stem cells residing in the basal layer of the limbus, the junction between the cornea and the sclera. The limbus provides the limbal epithelial stem cells (LESCs) with an optimal microenvironment, the limbal niche, which strictly regulates their proliferation and differentiation. Disturbances to the LESCs and/or their niche can lead to the pathologic condition known as limbal stem cell deficiency (LSCD) whereby the corneal epithelium is not generated effectively. This has deleterious effects on the corneal and visual function, due to impaired healing and secondary corneal opacification. In this concise review, we summarize the characteristics of LESCs and their niche, and present the current and future perspectives in the management of LSCD with an emphasis on restoring the function of the limbal niche.

The Limbal Niche and Regenerative Strategies

The protective function and transparency provided by the corneal epithelium are dependent on and maintained by the regenerative capacity of limbal epithelial stem cells (LESCs). These LESCs are supported by the limbal niche, a specialized microenvironment consisting of cellular and non-cellular components. Disruption of the limbal niche, primarily from injuries or inflammatory processes, can negatively impact the regenerative ability of LESCs. Limbal stem cell deficiency (LSCD) directly hampers the regenerative ability of the corneal epithelium and allows the conjunctival epithelium to invade the cornea, which results in severe visual impairment. Treatment involves restoring the LESC population and functionality; however, few clinically practiced therapies currently exist. This review outlines the current understanding of the limbal niche, its pathology and the emerging approaches targeted at restoring the limbal niche. Most emerging approaches are in developmental phases but show promise for treating LSCD and accelerating corneal regeneration. Specifically, we examine cell-based therapies, bio-active extracellular matrices and soluble factor therapies in considerable depth.

Corneal Epithelial Stem Cells-Physiology, Pathophysiology and Therapeutic Options

In the human cornea, regeneration of the epithelium is regulated by the stem cell reservoir of the limbus, which is the marginal region of the cornea representing the anatomical and functional border between the corneal and conjunctival epithelium. In support of this concept, extensive limbal damage, e.g., by chemical or thermal injury, inflammation, or surgery, may induce limbal stem cell deficiency (LSCD) leading to vascularization and opacification of the cornea and eventually vision loss. These acquired forms of limbal stem cell deficiency may occur uni- or bilaterally, which is important for the choice of treatment. Moreover, a variety of inherited diseases, such as congenital aniridia or dyskeratosis congenita, are characterized by LSCD typically occurring bilaterally. Several techniques of autologous and allogenic stem cell transplantation have been established. The limbus can be restored by transplantation of whole limbal grafts, small limbal biopsies or by ex vivo-expanded limbal cells. In this review, the physiology of the corneal epithelium, the pathophysiology of LSCD, and the therapeutic options will be presented.

Corneal Epithelial Stem Cell Supernatant in the Treatment of Severe Dry Eye Disease: A Pilot Study

PURPOSE

To report the subjective assessment of topical self-administered, cadaver-derived corneal epithelial stem cell supernatant for treatment of severe dry eye disease (DED).

METHODS

Thirty-four eyes of 17 patients with advanced DED as defined by Standardized Patient Evaluation of Eye Dryness (SPEEDTM) questionnaire ≥14, Ocular Surface Disease Index (OSDI©) score ≥40 and documented attempt of at least six conventional dry eye therapies were enrolled into a prospective clinical trial at a single private practice institution. Treatment consisted of patient self-administered topical instillation of the corneal epithelial stem cell-derived product four times daily in both eyes for 12 weeks. Patient-reported outcome measures (PROMs) were taken with the SPEEDTM questionnaire (the main outcome variable), OSDI© score and visual analog score (VAS; UNC Dry Eye Management Scale©), and objective clinical measurements were taken with best-corrected visual acuity (BCVA), corneal topographic index measurements and tear film osmolarity. These measurements were compared at baseline versus the endpoint at completion of the 12-week treatment.

RESULTS

All 34 eyes tolerated the treatment without any adverse events or significant side effects. Compared with baseline, both the SPEEDTM questionnaire and the VAS significantly improved at the conclusion of the 12-week treatment (p = 0.0054 and p = 0.0202, respectively). The OSDI© improved by an average of 10.9 points after the treatment but was not statistically significant (p = 0.1409). There were no significant changes in any of the objective clinical measurements. None of the study subjects failed to complete the treatment course, experienced decrease in any of the PROMs or lost one or more lines of BCVA during the follow-up period.

CONCLUSION

Topical corneal epithelial stem cell-derived supernatant that can be self-administered by the patient shows promise at improving patient symptoms and quality of life in the setting of severe DED that is unresponsive to conventional therapies.

The Use of Autologous Serum to Reverse Severe Contact Lens-induced Limbal Stem Cell Deficiency

PURPOSE

To describe the efficacy of autologous serum (AS) eye drops to reverse severe contact lens (CL)-induced limbal stem cell (LSC) deficiency (LSCD).

METHODS

This is a prospective, uncontrolled, interventional case series that enrolled 20 eyes of 14 consecutive patients diagnosed with severe CL-induced LSCD at presentation, based on clinical examination, at a tertiary referral center for the period December 2016 to December 2018. All eyes underwent AS treatment for at least 2 weeks with a follow-up for at least 2 months. Demographic data and treatment outcomes were collected and analyzed.

RESULTS

The mean patient age at presentation was 30.5 years (range, 19-49 years). The mean duration of soft contact lens wear was 15.6 years (SD, 7.58 years; range, 5-31 years). All study eyes had pain and blurred vision at presentation. All eyes had recurrent or persistent corneal epithelial defect, stromal scarring and opacity, and superficial vascularization and peripheral pannus at presentation. Aggressive treatment with AS succeeded in all eyes. Signs and symptoms of LSCD stabilized in all eyes within 2 weeks and resolved in 6 eyes (30.0%) in 2 weeks, 9 eyes (45.0%) in 4 weeks, and 5 eyes (25.0%) in 8 weeks. The mean follow-up time was 9.45 ± 1.79 weeks (range, 8-24 weeks).

CONCLUSIONS

Early identification and aggressive treatment of the ocular surface disease with AS can medically reverse severe CL-induced LSCD and prevent the need for surgical intervention.

Fingerprick Autologous Blood in the Treatment of Severe Dry Eyes and Ocular Surface Disease

PURPOSE

To evaluate the efficacy of autologous blood eye drops in patients diagnosed with severe ocular surface disease and dry eye who were unresponsive to conventional therapy and who would otherwise be considered for autologous serum eye drops.

METHODS

A total of 38 eyes of 19 patients (15 women and 4 men) with ocular surface disease and severe dry eye refractory to conventional treatment were treated with fingerprick autologous blood 4 times daily for 6 months. Follow-up visits occurred at 1-, 3-, and 6-month intervals. At each visit, visual acuity, Oxford Grading Scheme score, tear film break-up time, Schirmer test, and ocular surface disease index were measured.

RESULTS

There was a significant improvement in the ocular surface staining score at all time gates. The mean score at presentation was 2.13, and this improved to 1.50 at 1 month (P < 0.001), 1.29 at 3 months (P < 0.01), and 1.42 at 6 months (P < 0.01). There was an improvement in tear film break-up time from 4.75 seconds at baseline to 6.79 seconds at 3 months (P < 0.01) and 7.0 seconds at 6 months (P < 0.001). An improvement in the Schirmer test was only found at 6 months with an improvement from 3.67 mm to 13.33 mm (P < 0.05). There was no statistical change in visual acuity at any time gate or ocular surface disease index score, although 83% of patients reported an improvement in their symptoms at 6 months. There were no adverse events reported.

CONCLUSIONS

Fingerprick autologous blood is an effective, readily accessible, and safe therapy for the treatment of recalcitrant cases of severe ocular surface disease and dry eye unresponsive to conventional therapy.

Assessment of response to multimodal management of neurotrophic corneal disease

PURPOSE

To characterize patients with neurotrophic keratopathy (NK) and describe treatment outcomes.

METHODS

Setting: Two institutional tertiary cornea clinics.

PATIENTS

Medical record review of 37 consecutive patients (37 eyes) with NK.

INTERVENTION

Management of NK.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), epithelial defects (ED), re-epithelialization time, number of perforations, need for penetrating keratoplasty and tarsorrhaphy.

RESULTS

Average age was 64.4 ± 15.0 years, with 59.5% male patients. Average follow up time was 20.8 ± 32.6 months. Moderate to severe NK (Mackie Stage) was present in 62.1% of patients. Herpetic, neurosurgical and pars plana vitrectomy were the top three causes in each Mackie Stage. 72.9% used topical steroids to treat inflammatory ocular disease. Mean number of EDs was 1.6 per patient averaging 85 days to heal. Persistent EDs affected 56.7%. Corneal perforation (18.9%) was more likely with advanced age, herpetic cause and Stage 3 presentation. Tarsorrhaphy was performed in 35% of patients and were more likely with Stage 3 presentation. Referral for neurotization occurred in 10.8%. Evisceration was required in 2 eyes. BCVA of 20/40 or better was achieved in 21.6% of eyes at last follow up.

CONCLUSIONS

NK is chronic, frequently visually disabling with multiple contributing factors requiring different treatment modalities. Herpetic, pars plana vitrectomy and neurosurgical causes constitute a significant proportion of NK. Persistent epithelial defects should be rapidly managed as corneal perforation is a serious complication. Advanced age, herpetic cause and Mackie Stage 3 at diagnosis are significant risk factors for corneal perforation.

Corneal graft melting: a systematic review

Corneal graft melting is a severe complication of keratoplasty. This review is to summarize the incidence, the pathogenesis, the risk factors, the prognosis and the prevention of corneal graft melting after keratoplasty. We systematically searched PubMed, Web of Science and WanFang database to retrieve potentially eligible articles about relevant clinical reports and animal experiments. We read the full texts to identify eligible articles. The selection of studies and data extraction were performed independently by two reviewers. In conclusion, the pathogenesis of corneal graft melting is complicated, and many risk factors are closely related to corneal graft melting. Analysis of pathogenesis and risk factors of corneal graft melting can facilitate the development of targeted therapies to better guide clinical practice.

The Role of Multisystem Disease in Composition of Autologous Serum tears and ocular surface symptom improvement

PURPOSE

Autologous serum tears (AST) contain growth factors and vitamins similar to those in healthy tears and are an effective treatment option for ocular surface disease. This study determined the differences in composition of AST in patients with systemic diseases versus patients with localized ocular surface diseases and the effects on ocular surface symptom improvement.

METHOD

An observational study was performed on 53 patients with either systemic diseases (Group I) or localized ocular surface diseases (Group II) who were prescribed AST. Concentrations of epidermal growth factor (EGF), interleukin 8 (IL-8), fibronectin, vitamin A, and tumor necrosis factor-α (TNF-α) were determined through ELISA assays from patients in both groups. The Ocular Surface Disease Index (OSDI) scores were calculated prior to and 6 weeks after initiation of treatment with AST for new patients.

RESULTS

The average concentration of EGF in Group I (29.39 pg/ml ± 52.85 pg/ml) was significantly lower than in Group II (88.04 pg/ml ±113.75 pg/ml) (p < 0.05). Levels of fibronectin, IL-8, and vitamin A were similar in both groups. There was a 24% reduction in OSDI score 6 weeks after initiation in Group I compared to a 36% reduction reported in Group II (p = 0.065). The OSDI score was reduced significantly after the treatment in all subjects (p = 0.002).

CONCLUSION

Serum tears are a promising therapy for management of ocular surface disease and associated symptoms. The differences between levels of EGF in patients with localized ocular surface disease and systemic inflammatory disease may account for differences in therapeutic outcome.

Emerging Approaches for Ocular Surface Regeneration

Purpose of review

In this manuscript, the recent advancements and novel approaches for regeneration of the ocular surface are summarized.

Recent findings

Following severe injuries, persistent inflammation can alter the rehabilitative capability of the ocular surface environment. Limbal stem cell deficiency (LSCD) is one of the most characterized ocular surface disorders mediated by deficiency and/or dysfunction of the limbal epithelial stem cells (LESCs) located in the limbal niche. Currently, the most advanced approach for revitalizing the ocular surface and limbal niche is based on transplantation of limbal tissues harboring LESCs. Emerging approaches have focused on restoring the ocular surface microenvironment using (1) cell-based therapies including cells with capabilities to support the LESCs and modulate the inflammation, e.g., mesenchymal stem cells (MSCs), (2) bio-active extracellular matrices from decellularized tissues, and/or purified/synthetic molecules to regenerate the microenvironment structure, and (3) soluble cytokine/growth factor cocktails to revive the signaling pathways.

Summary

Ocular surface/limbal environment revitalization provide promising approaches for regeneration of the ocular surface.

Strategies for reconstructing the limbal stem cell niche

The epithelial cell layer that covers the surface of the cornea provides a protective barrier while maintaining corneal transparency. The rapid and effective turnover of these epithelial cells depends, in part, on the limbal epithelial stem cells (LESCs) located in a specialized microenvironment known as the limbal niche. Many disorders affecting the regeneration of the corneal epithelium are related to deficiency and/or dysfunction of LESCs and the limbal niche. Current approaches for regenerating the corneal epithelium following significant injuries such as burns and inflammatory attacks are primarily aimed at repopulating the LESCs. This review summarizes and assesses the clinical feasibility and efficacy of current and emerging approaches for reconstruction of the limbal niche. In particular, the application of mesenchymal stem cells along with appropriate biological scaffolds appear to be promising strategies for long-term revitalization of the limbal niche.

Application of autologous serum eye drops after pterygium surgery: a prospective study

PURPOSE

The study aims to determine the effect of 50% autologous serum drops (ASD) on corneal healing and patient comfort following pterygium surgery.

METHODS

Fifty eyes of 50 patients who underwent pterygium excision combined with autologous conjunctival graft were included in this prospective randomized study: in 25 eyes, 50% ASD. In the remaining 25 eyes, conventional artificial tears (CAT) were applied postoperatively until corneal epithelium had completely epithelialized. Corneal epithelium healing speed, visual analog scale (VAS) for postoperative pain assessment, conjunctival inflammation, and recurrences were evaluated. Patients were followed up for 6 months.

RESULTS

Mean corneal epithelium closure time was 3.16 ± 0.37 days (range 3 and 4 days) in ASD group and 4.96 ± 0.84 days in CAT group (range 4 and 6 days), and the difference was statistically significant (p < 0.001). VAS scores were significantly lower in ASD group than CAT group in the first 5 days after surgery. In 9 of 50 eyes, moderate conjunctival inflammation continued 1 month: 4 (16%) in ASD group and 5 (20%) in CAT group (p = 0.713). In total, pterygium recurrence was seen in 5 (10%) eyes: 2 eyes (8%) in ASD group and 3 eyes (12%) in CAT group (p = 0.637).

CONCLUSION

ASD accelerated corneal epithelial healing following pterygium surgery. ASD group had lesser pain that was seem to be related with accelerated corneal epithelial healing.

Effects of 20% Human Serum on Corneal Epithelial Toxicity Induced by Benzalkonium Chloride: In Vitro and Clinical Studies

PURPOSE

Benzalkonium chloride (BAK), the most commonly used preservative in ophthalmic solutions, is known to cause toxicity in the corneal epithelium. In this study, we investigated the effects of 20% human serum in cultures of BAK-damaged human corneal epithelial cells (hCECs) and in patients with toxic corneal epitheliopathy induced by BAK-containing eye drops.

METHODS

hCECs were exposed to various concentrations of BAK (0%, 0.002%, 0.02%, and 0.2%) in the presence or absence of 20% human serum. After 24 hours, the metabolic activity, proliferation, apoptosis, and proinflammatory cytokine expression were evaluated in the cells. Also, cell migration was assessed using a scratch test. In the clinical study, 24 patients with toxic corneal epitheliopathy secondary to BAK-containing antiglaucoma eye drops were treated with topical application of 20% autologous serum, and corneal epithelial integrity was evaluated.

RESULTS

BAK induced cytotoxicity in hCECs by inhibiting the metabolic activity, proliferation, and migration and by increasing apoptosis in a concentration-dependent manner. The level of proinflammatory cytokine IL-8 was elevated in BAK-treated cells. Addition of 20% human serum to the cultures significantly promoted the cell metabolic activity, proliferation, and migration while markedly reducing apoptosis. In line with the in vitro results, corneal punctate epithelial erosions were decreased from a National Eye Institute scale score of 4.2 ± 2.1 to 1.3 ± 1.7 in 20 of 24 patients (84%) after treatment with 20% autologous serum.

CONCLUSIONS

Data demonstrate that 20% human serum is effective in treating BAK-induced cytotoxicity in hCECs and provides a basis for using 20% autologous serum for patients with preservative-induced corneal epitheliopathy.

Systematic review of randomized controlled trials in the treatment of dry eye disease in Sjogren syndrome

Primary Sjögren’s syndrome is an autoimmune disease characterized by dry eye and dry mouth. We systematically reviewed all the randomized controlled clinical trials published in the last 15 years that included ocular outcomes. We found 22 trials involving 9 topical, 10 oral, 2 intravenous and 1 subcutaneous modalities of treatment. Fluoromethalone eye drops over 8 weeks were more effective than topical cyclosporine in the treatment of dry eye symptoms and signs; similarly, indomethacin eye drops over 1 month were more efficacious than diclofenac eye drops. Oral pilocarpine 5 mg twice daily over 3 months was superior to use of lubricants or punctal plugs for treating dry eye, but 5% of participants had gastrointestinal adverse effects from pilocarpine, though none discontinued treatment. In contrast, etanercept, a TNF-alpha blocking antibody, administered as subcutaneous injections twice weekly, did not improve dry eye significantly compared to placebo injections. In conclusion, topical corticosteroids have been shown to be effective in dry eye associated with Sjögren’s syndrome. As some topical non-steroidal anti-inflammatory drugs may be more effective than others, these should be further evaluated. Systemic secretagogues like pilocarpine have a role in Sjögren’s syndrome but the adverse effects may limit their clinical use. It is disappointing that systemic cytokine therapy did not produce encouraging ocular outcomes but participants should have assessment of cytokine levels in such trials, as those with higher baseline cytokine levels may respond better.

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Autologous serum eye-drops and enhanced epithelial healing time after photorefractive keratectomy

BACKGROUND

The aim of the study is to test whether use of autologous serum eye-drops can provide earlier epithelial healing following the application of photorefractive keratectomy.

METHOD

Sixty patients (60 eyes) underwent photorefractive keratectomy for myopia. Thirty eyes received autologous serum drops (Study group) while 30 eyes received conventional artificial tears (Control group) after photorefractive keratectomy. An 8 mm epithelial opening was prepared with the application of 18 per cent alcohol for 20 seconds. Photorefractive keratectomy was performed using ESIRIS excimer laser (SCHWIND, Kleinostheim, Germany) with an optic zone of 6.5 mm. Total duration of epithelial healing was monitored as the main outcome measure. The comparisons were done with chi-square test and independent samples t-test. Statistical significance was considered at p < 0.05.

RESULTS

Preoperative myopic spherical refraction and ablation depths were similar in the study and control groups. The mean duration for epithelial healing was about one day shorter in the eyes receiving autologous serum compared to the eyes receiving conventional treatment (2.2 ± 0.25 days versus 3 ± 0 days, p = 0.001). All eyes achieved 6/7.5 or better uncorrected visual acuity in six months. In both groups, more than 90 per cent of eyes were within ±0.50 D of emmetropia in 12 months. No significant difference was noted for the incidence of +1 haze.

CONCLUSION

Use of autologous serum drops reduces epithelial healing duration following surface ablation for two days.

Undiluted Serum Eye Drops for the Treatment of Persistent Corneal Epitheilal Defects

Several studies found that 50–100% serum eye drops provided greater benefits without inducing detrimental effects on the corneal epithelial healing. This study assessed the efficacy of undiluted serum eye drops for the treatment of persistent corneal epithelial defects (PED). A total of 109 eyes received 100% serum eye drops for PED were recruited into this study. The data were compared with an historical control group of 79 eyes with PED who received conventional treatments from 2006–2011 at the same institution. Main outcome measures were complete healing of PED and incidence of adverse events. No significant difference in demographics between the 2 groups was noted. The success rate of the treatment and control groups were 87.16% (95% CI 0.79–0.93) and 69.62% (95% CI 0.59–0.80) (P = 0.001), respectively. The median time to complete epithelialization was 14 days (95% CI 12–21) in the treatment group and 28 days (95% CI 21–59) in the control group (P = 0.001). Serum treatment, primary diagnosis of non-limbal stem cell deficiency etiology, and prior contact lens wear significantly correlated with the corneal re-epithelialization. There were no serious side effects encountered during the study period. In conclusion, undiluted serum therapy is effective and safe for treating PED.

Solvent/Detergent Virally Inactivated Serum Eye Drops Restore Healthy Ocular Epithelium in a Rabbit Model of Dry-Eye Syndrome

Application of autologous serum eye drops (SEDs) is a recognized means to treat severe dry-eye syndrome (DES). Due to the inconvenience and difficulty of preparing SEDs from some patients, producing SEDs from allogeneic blood donations is gaining popularity. A major safety concern associated with allogeneic blood is virus transmission. We therefore herein evaluated the possibility of applying a solvent/detergent (S/D) treatment to inactivate viruses and studied the impacts of such treatment of SEDs to resolve DES in a rabbit model. Sera prepared from the blood of five rabbits were pooled and divided into two sub-pools. One was untreated (SEDs), while the other was virally-inactivated with 1% Tri-n-butyl phosphate/1% Triton X-45 at 31°C for 1 h (S/D-SEDs). DES was induced in rabbits using 0.1% benzalkonium chloride (BAC). Rabbits were divided into five groups of two rabbits each. One group was untreated (control), three were treated twice daily for 3 weeks using PBS, SEDs, or S/D-SEDs, and the last received an additional 0.1% BAC (as the negative control). The DES condition was determined by measuring aqueous tear secretion (Schirmer’s test), corneal fluorescein staining, a corneal histologic examination, TUNEL stain apoptosis, and corneal inflammatory marker (tumor necrosis factor-α, interleukin (IL)-1β, IL-8, and IL-6) expressions. We first confirmed that SEDs and S/D-SEDs had similar protein profiles and transforming growth factor (TGF)-β contents. Animal experiments showed that tear secretion did not significantly differ between the SED and S/D-SED groups but was significantly higher than in the PBS group. Eye fluorescein staining revealed dramatic improvements in epithelial defects in groups treated with SEDs or S/D-SEDs, and hematoxylin/eosin staining revealed microscopic epithelial layers similar to those of the untreated controls. Inflammatory markers and TUNEL studies showed that healthy epithelium had been restored in groups treated with SEDs or S/D-SEDs. In conclusion, this preclinical study supports the possibility of using S/D virally inactivated SEDs to treat DES and restore a normal epithelium.

Human Serum Eye Drops in Eye Alterations: An Insight and a Critical Analysis

Human serum contains a physiological plethora of bioactive elements naturally released by activated platelets which might have a significant effect on the regeneration of corneal layers by stimulating the cell growth. This mechanism supported the use of human serum eye drops in some ocular diseases associated with dystrophic changes and alterations of the tear film, such as persistent corneal epithelial defects and dry eye syndrome. We focused our effort on potential benefits and limitations of the use of human serum eye drops when conventional therapies failed. We reviewed the recent literature by reporting published studies from 2010 to 2014. Despite the limited evaluated study populations, most of the clinical studies have confirmed that serum eye drop therapy is effective in corneal healing by reducing ocular symptom, particularly during the short-term follow-up. In addition, three recent published studies have shown the efficacy of the serum eye drop therapy in comparison to traditional ones in intractable patients. Besides, reported ongoing clinical studies confirmed the open debate regarding the use of biologic tools for cornea regeneration. Results from these studies might open novel challenges and perspectives in the therapy of such refractory patients.

Degeneration and Regeneration of Subbasal Corneal Nerves after Infectious Keratitis: A Longitudinal In Vivo Confocal Microscopy Study

PURPOSE

To investigate the longitudinal alterations of subbasal corneal nerves in patients with infectious keratitis (IK) during the acute phase, cessation of treatment, and the recovery phase by in vivo confocal microscopy (IVCM).

DESIGN

Prospective, longitudinal, case-control, single-center study.

PARTICIPANTS

Fifty-six eyes of 56 patients with the diagnosis of bacterial (n=28), fungal (n=15), or Acanthamoeba (n=13) keratitis were included in the study. Thirty eyes of 30 normal volunteers constituted the control group.

METHODS

Corneal sensation and serial IVCM of the central cornea were performed prospectively using the Heidelberg Retina Tomograph 3/Rostock Cornea Module (Heidelberg Engineering, Heidelberg, Germany). The IVCM images were assessed at 3 time points: at the acute phase (first visit to the cornea service), at cessation of antimicrobial treatment, and up to 6 months after the resolution of infection.

MAIN OUTCOME MEASURES

Total nerve number and length, main nerve trunks, branching, and corneal sensation were assessed during the follow-up period.

RESULTS

Corneal nerves were reduced significantly during the acute phase in eyes with IK compared with controls across all subgroups, with total nerve length of 5.47±0.69 mm/mm2 versus 20.59±1.06 mm/mm2 (P<0.0001). At the cessation of treatment, corneal nerves in patients with IK had regenerated, including total nerve length (8.49±0.94 mm/mm2; P=0.02) and nerve branch length (4.80±0.37 mm/mm2; P=0.005). During the recovery phase, after resolution of infection, corneal nerves regenerated further, including total nerve length (12.13±1.97 mm/mm2; P=0.005), main nerve trunk length (5.80±1.00 mm/mm2; P=0.01), and nerve branch length (6.33±0.76 mm/mm2; P=0.003) as compared with the acute phase, but were still significantly lower when compared with controls (P<0.05 for all parameters). Corneal degeneration and regeneration correlated with corneal sensation (r=0.47; P=0.0009).

CONCLUSIONS

Patients with IK who sustain profound loss of corneal nerves during the acute phase of infection demonstrate increased corneal nerve density during the first 6 months after the resolution of infection. However, despite significant nerve regeneration, corneal nerve density does not recover fully and remains low compared to controls. By providing an objective methodology to monitor corneal re-innervation, IVCM adds potentially important findings that may have implications for clinical management and surgical planning.