Improving the anti-inflammatory effect of serum eye drops using allogeneic serum permissive for regulatory T cell induction

Allogeneic serum-based eye drops may give better results than autologous drops in Sjögren's syndrome dry eye

PURPOSE

Sjögren's syndrome (SS) may cause severe dry eye symptoms. One of the therapeutic option known for almost 40 years are autologous serum eye drops (ASEDs). Due to the presence of many pro-inflammatory factors in the autologous serum of SS patients, the use of allogeneic serum is often considered a better option. In our facility almost one-fifth of the patients using allogeneic serum-based eye drops (alloSEDs) suffered from autoimmune diseases, including SS. The study aim was to compare the effectiveness of both ASEDs and alloSEDs in SS patients.

METHODS

From the group of SS patients using alloSEDs, five female SS patients aged 39-73 years were selected. They had the longest history of the use of the product. The analysis was based on OSDI forms and internal questionnaires which compared the effects of ASEDs and alloSEDs application. The patients used alloSEDs for a period of 5-28 months. All had previously used ASEDs for at least 2 years.

RESULTS

For all five patients the mean OSDI after application of ASEDs and before introducing alloSEDs was 68.71, while the mean OSDI after the use of alloSEDs was 30.49.

CONCLUSION

In SS the treatment results are better with alloSEDs than with ASEDs. Almost all SS patients who applied both autologous and allogeneic drops reported better effects with the latter as also confirmed by the study cases.

Correlation between serum cytokine levels and the effect of allogeneic serum-based eye drops

INTRODUCTION

The Institute of Hematology and Transfusion Medicine (IHTM) in Warsaw has produced autologous serum eye drops (ASEDs) for the treatment of Dry Eye Syndrome (DES) since 1991. In 2019, IHTM introduced allogeneic tears (alloSEDs) for patients on long-term treatment.

MATERIALS AND METHODS

114 patients who applied alloSEDs were included in the study.They were asked to complete the OSDI questionnaire before and after using ASEDs and 100 units of alloSEDs drops from each donation. The OSDI index rates DES severity (0 no symptoms; 100 severe). We also compared the content of IL-1β, IL-2, IL- 6, IL-10 and VEGF in ASEDs (38 samples) and alloSEDs (15 serum samples). The study data covered the 2019-2022 period.

RESULTS

114 patients participated in the study. We compared the the effectiveness of ASEDs and alloSEDs. The average, OSDI dropped from 68.42 ± 5,86 (before application) to 51.05 ± 19,06 (after application). Data from the questionnaires (prepared at IHTM) completed and returned (41/114) present the most common indications for the use of serum drops, including DES with no underlying disease, DES secondary to GvHD (Graft versus Host Disease), Sjögren's Syndrome (SS). The study reported higher cytokine levels associated with disease entities such as SS. After application of drops with high cytokine levels, patients reported adverse reactions such as sand under the eyelids, impaired visual acuity, and worse eye lubrication.

CONCLUSIONS

AlloSEDs with acceptably low values of pro-inflammatory cytokines and sufficiently high levels of VEGF growth factor may contribute to alleviation of inflammatory eye symptoms.

Current Advances in Regenerative Strategies for Dry Eye Diseases: A Comprehensive Review

Dry eye disease (DED) is an emerging health issue affecting millions of individuals annually. Ocular surface disorders, such as DED, are characterized by inflammation triggered by various factors. This condition can lead to tear deficiencies, resulting in the desiccation of the ocular surface, corneal ulceration/perforation, increased susceptibility to infections, and a higher risk of severe visual impairment and blindness. Currently, the clinical management of DED primarily relies on supportive and palliative measures, including the frequent and lifelong use of different lubricating agents. While some advancements like punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts have been attempted, they have shown limited effectiveness. Recently, there have been promising developments in the treatment of DED, including biomaterials such as nano-systems, hydrogels, and contact lenses for drug delivery, cell-based therapies, biological approaches, and tissue-based regenerative therapy. This article specifically explores the different strategies reported so far for treating DED. The aim is to discuss their potential as long-term cures for DED while also considering the factors that limit their feasibility and effectiveness. These advancements offer hope for more effective and sustainable treatment options in the future.

New developments in the management of persistent corneal epithelial defects

A persistent epithelial defect (PED) is a corneal epithelial defect that failed to heal after 2weeks. It is a condition that carries much morbidity, and our understanding of PED remains poor, with current treatment methods often having unsatisfactory outcomes. With PEDs becoming more prevalent, more efforts are required to establish reliable treatment modalities. Our reviews describe the causes of PEDs and the different approaches developed to manage them, as well as their associated limitations. Emphasis is placed on understanding various advances in the development of new treatment modalities. We have also described a case of a woman with a background of graft-versus-host disease on long-term topical corticosteroids who developed complicated PED involving both eyes. The current approach to managing PEDs generally involves exclusion of an active infection, followed by treatment modalities that aim to encourage corneal epithelial healing. Success rates, however, remain far from desirable, as treatment remains challenging due to multiple underlying etiologies. In summary, advances in the development of new therapies may be able to facilitate progress in the understanding and treatment of PED.

Use of allogeneic platelet-rich plasma for the treatment of autoimmune ocular surface disorders: case series

Purpose

To assess the effectiveness of topical allogeneic platelet-rich plasma (PRP) eye drops for the treatment of symptoms and clinical signs in patients with severe dry eye disease as a secondary condition caused by Sjögren's syndrome (SS).

Design

Case series and literature review.

Methods

Six eyes from three consecutive patients with severe dry eye from SS were evaluated. The eyes were treated with allogeneic topical PRP eye drops, with one drop applied six times daily for 3 months. A post-treatment follow-up evaluation was conducted 3 months after treatment suspension. We evaluated subjective symptoms, visual acuity, tear breakup time, the results of Schirmer's I test, fluorescein corneal and conjunctival staining, and corneal sensitivity.

Results

The symptoms and visual acuity improved significantly in all patients. There was a significant improvement in corneal sensitivity and a decrease or disappearance of fluorescein corneal staining.

Conclusion

The treatment with allogenic PRP eye drops of patients with SS-related severe dry eye disease has proven to be very effective, with an improvement in symptoms and main clinical signs.

Proteomic Characterization of Plasma Rich in Growth Factors and Undiluted Autologous Serum

Over the last three decades, there has been special interest in developing drugs that mimic the characteristics of natural tears for use it in the treatment of several ocular surface disorders. Interestingly, the composition of blood plasma is very similar to tears. Therefore, different blood-derived products like autologous serum (AS) and plasma rich in growth factors (PRGF) have been developed for the treatment of diverse ocular pathologies. However, scarce studies have been carried out to analyze the differences between both types of blood-derived products. In the present study, blood from three healthy donors was drawn and processed to obtain AS and PRGF eye drops. Then, human corneal stromal keratocytes (HK) were treated with PRGF or undiluted AS. Proteomic analysis was carried out to analyze and characterize the differential protein profiles between PRGF and AS, and the differentially expressed proteins in HK cells after PRGF and AS treatment. The results obtained in the present study show that undiluted AS induces the activation of different pathways related to an inflammatory, angiogenic, oxidative stress and scarring response in HK cells regarding PRGF. These results suggest that PRGF could be a better alternative than AS for the treatment of ocular surface disorders.

A Review of Ocular Graft-versus-Host Disease: Pathophysiology, Clinical Presentation and Management

Graft-versus-host disease is a common complication following allogeneic hematopoetic stem cell transplantation that can affect multiple organ systems, including the eyes. Ocular GVHD (oGVHD) is characterized by a T cell-mediated immune response that leads to immune cell infiltration and inflammation of ocular structures, including the lacrimal glands, eyelids, cornea and conjunctiva. oGVHD has a significant negative impact on visual function and quality of life and successful management requires a multi-disciplinary approach with frequent monitoring. Here, we review the pathophysiology and clinical presentation of oGVHD, along with current therapeutic strategies based on our clinical experience and the reported literature.

Establishment of functional epithelial organoids from human lacrimal glands

Background

Tear deficiency due to lacrimal gland (LG) dysfunction is one of the major causes of dry eye disease (DED). Therefore, LG stem cell-based therapies have been extensively reported to regenerate injured lacrimal tissue; however, the number of stem cells in the LG tissue is low, and 2D long-term cultivation reduces the differentiation capacity of stem cells. Nevertheless, 3D LG organoids could be an alternative for a DED therapy because it is capable of prolonged growth while maintaining the characteristics of the LG tissue. Here, we report the development of LG organoids and their application as cell therapeutics.

Methods

Digested cells from human LG tissue were mixed with Matrigel and cultured in five different media modified from human prostate/salivary organoid culture media. After organoid formation, the growth, specific marker expression, and histological characteristics were analyzed to authenticate the formation of LG organoids. The secretory function of LG organoids was confirmed  through calcium influx or proteomics analysis after pilocarpine treatment. To explore the curability of the developed organoids, mouse-derived LG organoids were fabricated and transplanted into the lacrimal tissue of a mouse model of DED.

Results

The histological features and specific marker expression of LG organoids were similar to those of normal LG tissue. In the pilocarpine-treated LG organoid, levels of internal Ca²⁺ ions and β-hexosaminidase, a lysosomal protein in tear fluid, were increased. In addition, the secreted proteins from pilocarpine-treated lacrimal organoids were identified through proteomics. More than 70% of the identified proteins were proven to exosome through gene ontology analysis. These results indicate that our developed organoid was pilocarpine reactive, demonstrating the function of LG. Additionally, we developed LG organoids from patients with Sjogren’s syndrome patients (SS) and confirmed that their histological features were similar to those of SS-derived LG tissue. Finally, we confirmed that the mouse LG organoids were well engrafted in the lacrimal tissue two weeks after transplantation.

Conclusion

This study demonstrates that the established LG organoids resemble the characteristics of normal LG tissue and may be used as a therapy for patients with DED.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02133-y.

Amniotic membrane extract eye drops for ocular surface diseases: use and clinical outcome in real-world practice

PURPOSE

To study the indications and clinical outcomes, in a real-word setting, of amniotic membrane extract eye drops (AMEED) use for ocular surface disease (OSD).

METHODS

A retrospective study of patients treated with topical AMEED between January 2018 and January 2020 was conducted. Patients were classified in two groups according to specific OSD-dry eye disease (DED) and wound healing delay (WHD) groups. Demographics, comorbidities, treatment duration and clinical outcomes were analysed.

RESULTS

A total of 50 eyes of 36 patients with or without previous treatments were included. Patients in the DED group presented more systemic comorbidities (83 vs 22%; p < 0.001) and spent more mean time under AMEED treatment (10 vs 7.2 months average) than the WHD group (p = 0.0104). In four patients, long-term treatment (more than 24 months) was reported. Global similar symptomatic improvement was reported for both groups (DED 88.9% vs WHD 100%; p = 0.486), with the WHD group especially consisting in general relief (78%) and the DED group reporting more pain improvement (44%) (p = 0.011). Regarding patients with autologous serum as a previous treatment, no statistical differences were found in subjective or objective improvement. An overall success was achieved in 94.4% of the cases and no adverse events were found.

CONCLUSION

AMEED administration is a promising mean to treat OSD such as dry eye, persistent epithelial defect and corneal ulcers. Although AMEED may be effective in the treatment of severe DED and persistent epithelial defect or corneal ulcers, conclusions are limited owing to the absence of controlled clinical trials.

Quantification of Growth Factors and Fibronectin in Diverse Preparations of Platelet-Rich Plasma for the Treatment of Ocular Surface Disorders (E-PRP)

Purpose

The purpose of this study was to quantify the presence of growth factors (GFs) and fibronectin in autologous platelet-rich plasma for topical ocular use (E-PRP) comparing their concentration when different preparation and preservation procedures were applied.

Methods

E-PRP was prepared with blood from healthy volunteers. The count of platelets, leukocytes, and red blood cells in the whole blood and E-PRP were performed. The concentration of the GFs platelet-derived growth factor BB (PDGF-BB), transforming growth factor β1 (TGF-β1), epidermal growth factor (EGF), vascular endothelial growth factor A (VEGF-A), and fibronectin was determined in each of the four procedures applied including fresh, frozen at −20°C for 3 months, fresh-spin, and frozen-spin at −20°C E-PRP samples. Posterior statistical analysis was performed to establish significant differences between groups and between GFs in relation to the amounts of platelets.

Results

Platelets in the E-PRP doubled in the number of basal values of whole blood (P ≤ 0.01). The blood cells in the E-PRP decreased drastically in red cells (99%) and also in leukocytes (82%). The concentration of PDGF-BB and EGF was significantly higher (P < 0.01) when the E-PRP samples were frozen at −20°C. However, no significant differences were observed for TGF-β1, VEGF-A, and fibronectin (P > 0.05). The concentration of GFs in the E-PRP did not necessarily correlate with the number of platelets.

Conclusions

Freezing the E-PRP for 3 months at −20°C increased the concentration of important proteins, such as PDGF-BB and EGF, and maintained the levels of others. These findings are essential because treatments, such as E-PRP, used by patients with ocular surface dysfunctions tend to prolong it in time. In addition, subsequent centrifugation of the E-PRP decreased the values of TFG-β1, but not the other GFs, which would allow adjusting the concentration of TFG-β1, as necessary. This procedure guarantees their correct conservation and viability.

Translational Relevance

This work demonstrates how clinical application can be improved by starting from basic research. The quantification of GFs and fibronectin in platelet-rich plasma (PRP) helps to clarify which is the best mode of preparation and preservation of PRP for clinical applications. This allows to optimize the product that is delivered to the patients as a treatment for the dysfunctions of the ocular surface, guaranteeing that the conservation does not affect at all the quality of the PRP that it is going to be used.

Development and Optimization of Freeze-Dried Eye Drops Derived From Plasma Rich in Growth Factors Technology

Purpose

To investigate whether plasma rich in growth factors (PRGF) eye drops maintain their biological potential after a freeze drying process. The addition of a lyoprotectant like trehalose was also evaluated.

Methods

Blood from three healthy donors was collected to obtain eye drops by PRGF technology. The resultant eye drops were divided in four groups: PRGF, freeze-dried PRGF (PRGF lyo), and PRGF lyophilized mixed with 2,5% trehalose (PRGF lyo+2.5T) or 5% trehalose (PRGF lyof+5T). Chemical and biological characteristics were evaluated. Photorefractive keratectomy was performed on C57BL/6 mice which were divided in three treatment groups: control, PRGF, and PRGF lyo. Corneal wound healing and haze formation were evaluated macroscopically. Eyes were collected at 1, 2, 3, and 7 days after surgery, and were processed for histologic studies.

Results

The pH values of PRGF samples increased significantly after the lyophilization process. Osmolarity levels increased significantly in PRGF samples mixed with trehalose in comparison with PRGF samples without protectants. The freeze drying process maintained growth factors levels as well as the biological properties of PRGF eye drops even without the use of lyoprotectants. PRGF lyo treatment significantly decreased the re-epithelialization time and haze formation in photorefractive keratectomy-treated corneas regarding PRGF and control groups. Furthermore, the PRGF lyo group significantly decreased the number of smooth muscle actin-positive cells in comparison with the control group at each time of the study and at days 2 and 3 in the PRGF group.

Conclusions

The freeze drying process preserves the protein and growth factor content as well as the biological properties of PRGF eye drops, even without the use of protectants. Freeze-dried PRGF eye drops accelerate corneal tissue regeneration after photorefractive keratectomy in comparison with the control group.

Translational Relevance

Our study shows the feasibility to preserve the biological capability of PRGF eye drops as freeze-dried formulation, avoiding the addition of protectants.

Cord Blood Platelet Rich Plasma Derivatives for Clinical Applications in Non-transfusion Medicine

Cord blood platelet rich plasma (CB-PRP) derivatives have been investigated as potential therapeutic agents for the treatment of diverse conditions including ocular surface disease and skin ulcers. We have developed processes for the formulation of several CB-PRP preparations, which have different composition and attributes. Here we describe the molecular characteristics of these preparations and we make recommendations as to their most appropriate clinical application based on functional and immunomodulatory profiles. We show that incubation of adult peripheral blood mononuclear cells (PBMCs) with all three preparations dramatically reduced the production of INFγ and the expression of NKG2D and CD107a in NK, NKT, and T cells thus diminishing their activation, we propose that the likely mechanism is the high levels of soluble NKG2D ligands present in plasma. Of the three preparations we investigated, CB platelet lysate (PL) and platelet releaseate (PR) have higher concentrations of trophic and pro-angiogenic factors, CB platelet poor plasma (PPP) has the lowest concentration of all analytes measured. Based on these finding we propose that CB-PR is the most suitable raw material for skin wound patches, while CB-PL and PPP can be used to prepare eye drops for severe ocular surface pathologies and inflammatory conditions such as corneal ulcers or severe dry eye disease, respectively.

The effect of human platelet lysate on corneal nerve regeneration

AIM

This study aimed to test whether human platelet lysate (HPL) has neurotrophic ability for corneal nerve regeneration.

METHODS

We measured the neurotrophic factors in human peripheral serum (HPS) and two commercially available HPLs, UltraGRO and PLTMax. In vitro, we compared the growth rates, neuronal differentiation and immunostaining of neuron markers in mouse neuroblastoma cell line (Neuro-2a) and primary culture of mouse trigeminal ganglion cells that were cultivated in different concentrations of fetal bovine serum, HPS and HPL. In vivo, we created corneal wounds on Sprague Dawley rats with a rotating burr and evaluated the effects of topical HPL on wound healing and corneal nerve regeneration by in vivo confocal microscopy and corneal aesthesiometry.

RESULTS

HPLs had significantly higher concentrations of various neurotrophic factors compared with HPS (p<0.05). In Neuro-2a cells, 3% HPL was better at promoting neuronal growth and differentiation compared with HPS at the same concentration. HPL was also found to have superior neurotrophic effects compared with HPS in primary cultures of mouse trigeminal ganglion cells. In vivo, HPL-treated eyes had better corneal epithelial wound healing rate, nerve regeneration length and corneal touch threshold compared with eyes treated with artificial tears (p<0.05).

CONCLUSION

HPL has significantly higher concentrations of neurotrophic factors compared with HPS. It showed not only in vitro but also in vivo corneal neurotrophic abilities. Our results suggest that HPL may have a potential role in the treatment of diseases related to corneal nerve damage or degeneration.

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.

Hyaluronic Acid as an Alternative to Autologous Human Serum Eye Drops: Initial Clinical Results with High-Molecular-Weight Hyaluronic Acid Eye Drops

Introduction

Autologous serum eye drops (ASED) are used in the treatment of most severe stages of dry eye. Once introduced, it is currently considered impossible to return to other lubricating eye drops or other commercially available therapeutic regimen.

Materials and Methods

In a randomized study, non-preserved high-molecular-weight hyaluronic acid eye drops were offered as an alternative to 11 patients using autologous serum treatment for at least 3 months. The control group (n = 5) continued their treatment with ASED. The verum group (n = 6) used very-high-molecular-weight hyaluronic eye drops (Comfort Shield®) instead of the ASED.

Results

From four of initially six patients in the verum group that finished the study, 2 (50%) preferred to stay with the very-high-molecular-weight hyaluronic acid eye drops beyond the trial period, the other two returned to the earlier therapy with ASED. The control group continued their treatment as before and finished the study after 8 weeks.

Conclusion

For the first time, artificial eye drops, i.e., high-molecular-weight hyaluronic acid eye drops, offered an acceptable alternative to ASED. Some patients perceived these drops as even better than the patient's own serum. This is the first evidence that optimization of the molecular structure of hyaluronic acid can be used to create eye drops that are perceived to be better than other tested tear substitutes and even patients' own serum. This offers a new treatment perspective for patients with very severe dry eye disease.

Ocular surface system alterations in ocular graft-versus-host disease: all the pieces of the complex puzzle

PURPOSE

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cells transplantation, occurring in about half of transplanted patients. This condition seems to be the result of a progressive immune-mediated damage that can involve various tissues, including the eyes. The ocular surface system is the ocular structure most frequently impaired, and dry eye disease is considered the hallmark of ocular GVHD. Given the increasing prevalence and the frequent severe involvement of the ocular surface with vision-threatening complications, ocular GVHD represents a current diagnostic and therapeutic challenge. The purpose of this literature review is to describe all the clinical manifestations occurring in the setting of ocular GVHD, and to further report the outcomes of conventional and novel therapies.

METHODS

A literature search about ocular GVHD was performed in PubMed, Scopus, Medline databases, and ClinicalTrials.gov as well as through the reference lists of identified publications until January 2019. We have included RCTs, prospective observational studies, prospective and retrospective cohort studies, pilot studies, and review articles.

RESULTS

Overall, 107 articles, 3 book chapters, and 6 ongoing registered clinical trials were collected and analyzed. Ocular GVHD can affect all the structures of the entire ocular surface system, including lacrimal and meibomian glands, cornea, conjunctiva, eyelids, nasolacrimal duct, and tears. Current medical treatment is mainly focused on lubrication and control of drainage, tear evaporation, and ocular surface inflammation. Surgical treatment may be necessary in severe, recalcitrant, or complicated cases. Amniotic membrane and tectonic keratoplasty can be valid options to restore the integrity of the cornea. Recently, conjunctival and limbal transplantation from the same living-related bone marrow donor has been proposed to manage both dry eye and limbal stem cell deficiency, without any risk of immunologic rejection.

CONCLUSION

This review provides an up-to-date analysis on clinical findings and current and future management of ocular GVHD. A correct and prompt diagnosis along with an appropriate and aggressive treatment are fundamental for avoiding the occurrence of vision-threatening complications.

Comparison of growth factor and interleukin content of adult peripheral blood and cord blood serum eye drops for cornea and ocular surface diseases

INTRODUCTION

Various blood-derived products have been proposed for the topical treatment of ocular surface diseases. The aim of the study was to compare the different content of Growth Factors (GFs) and Interleukins (ILs) in peripheral blood (PB-S) and Cord Blood (CB-S) sera.

MATERIALS AND METHODS

Sera were obtained from 105 healthy adult donors (PB-S) and 107 umbilical/placental veins at the time of delivery (CB-S). The levels of epithelial-GF (EGF), fibroblast-GF (FGF), platelet-derived-GF (PDGF), insulin-GF (IGF), transforming-GF alpha (TGF-α,) and beta 1-2-3 (TGF-β1-β2-β3), vascular endothelial-GF (VEGF), nerve-GF (NGF), Interleukin (IL)-1β,IL-4,IL-6,IL-10, and IL-13 were assessed by Bio-Plex Protein Array System (Bio-Rad Laboratories, CA, USA). The Mann-Whitney test for unpaired data was applied to compare GFs and ILs levels in the two sources. The associations among each GF/IL level and the obstetric data for CB-S and hematological characteristics for PB-S were also investigated.

RESULTS

The levels of EGF, TGF-α, TGF-β2, FGF, PDGF, VEGF, NGF, IL-1B, IL-4, IL-6, IL-10, and IL-13 were significantly higher in CB-S compared to PB-S. Conversely, the levels of IGF-1, IGF-2, and TGF-β1 were significantly higher in PB-S. The female sex and the weight of the child showed a significant association in predicting EGF and PDGF levels.

CONCLUSION

A significantly different content in those GFs and ILs was demonstrated in the two blood sources. Since each GF/IL selectively regulates different cellular processes involved in corneal healing, the use of PB-S or CB-S should be chosen on the basis of the cellular mechanism to be promoted in each clinical case.

Dry eye disease and oxidative stress

Dry eye, an age-related condition, is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance and tear film instability. Environmental factors are also often implicated in dry eye including exposure to pollutants, ultraviolet (UV) radiation and ozone as well as the chronic use of preserved eyedrops such as in the treatment of glaucoma. These factors increase oxidative stress and ocular surface inflammation. Here, we reviewed the cellular, animal and clinical studies that point to the role of oxidative stress in dry eye disease. The biomarkers used to indicate oxidative damage in ocular surface tissues include 8-hydroxy-2 deoxyguanosine (8-OHdG), 4-hydroxynonenal (HNE) and malondialdehyde (MDD). Antioxidative defences in the ocular surface occur in the form of tear proteins such as lactoferrin and S100A proteins, and enzymes such as superoxide dismutase (SOD), peroxidase, catalase and mitochondrial oxidative enzymes. An imbalance between the level of reactive oxygen species (ROS) and the action of protective enzymes will lead to oxidative damage, and possibly inflammation. A small number of interventional studies suggest that oxidative stress may be directly targeted in topical therapy of dry eye treatment. For example, in vitro studies suggest that L-carnitine and pterostilbene, a blueberry component may reduce oxidative stress, and in animal studies, alpha-lipoic acid (ALP) and selenoprotein P may be helpful. Examples of treatments used in clinical trials include vitamin B12 eyedrops and iodide iontophoresis. With recent emphasis on ageing medicine and preventive holistic health, as well as the role of environmental science, research on oxidative stress in the ocular surface is likely to have increasing impact in the coming years.

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.

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.

The corneal epitheliotrophic abilities of lyophilized powder form human platelet lysates

Purpose

To evaluate whether lyophilized human platelet lysate (HPL) powder can preserve the growth factor concentrations and epitheliotrophic properties of liquid HPL, and potentially be used as a clinically-friendly treatment option.

Methods

Two commercialized liquid HPLs, UltraGRO TM (Helios, Atlanta, GA) and PLTMax (Mill Creek, Rochester, MI), were obtained and converted to lyophilized powder. After redissolution, lyophilized powder HPLs were compared with liquid HPLs, as well as human peripheral serum (HPS) and fetal bovine serum (FBS) in liquid or redissolved lyophilized powder forms. Concentrations of epidermal growth factor (EGF), transforming growth factor-β1 (TGF-β1), platelet-derived growth factor-AB (PDGF-AB) and platelet-derived growth factor-BB (PDGF-BB) were evaluated by enzyme-linked immunosorbent assay (ELISA). Human corneal epithelial cell line was incubated with the blood derivatives and evaluated for cell migration with scratch-induced directional wounding and proliferation with MTS assays. Cell differentiation was examined by transepithelial electrical resistance (TEER). Fluorescein staining and in vivo confocal microscopy were used to evaluate in vivo corneal epithelial wound healing in Sprague-Dawley rats that underwent corneal debridement and topical application of liquid and redissolved powder HPLs.

Results

Liquid form and redissolved lyophilized powder form HPLs had similar concentrations of EGF, TGF-β1, PDGF-AB and PDGF-BB. In vitro experiments on cell migration, proliferation and differentiation and rat models on wound healing demonstrated no significant difference between the liquid and redissolved lyophilized powder forms for HPLs, HPS and FBS. In vivo confocal microscopy revealed similar wound healing process at different layers of cornea after corneal epithelial debridement between liquid form and redissolved lyophilized power form of HPLs.

Conclusions

The redissolved lyophilized powder form of both commercialized HPLs showed similar growth factor concentrations and corneal epitheliotrophic abilities compared to the liquid form. Results suggest that the properties of liquid HPLs can be retained despite lyophilization and that lyophilized HPLs can be a treatment option for corneal epithelial disorders.

Regenerative Therapies in Dry Eye Disease: From Growth Factors to Cell Therapy

Dry eye syndrome is a complex and insidious pathology with a high level of prevalence among the human population and with a consequently high impact on quality of life and economic cost. Currently, its treatment is symptomatic, mainly based on the control of lubrication and inflammation, with significant limitations. Therefore, the latest research is focused on the development of new biological strategies, with the aim of regenerating affected tissues, or at least restricting the progression of the disease, reducing scar tissue, and maintaining corneal transparency. Therapies range from growth factors and cytokines to the use of different cell sources, in particular mesenchymal stem cells, due to their multipotentiality, trophic, and immunomodulatory properties. We will review the state of the art and the latest advances and results of these promising treatments in this pathology.

Comparison of corneal epitheliotrophic capacities among human platelet lysates and other blood derivatives

PURPOSE

To evaluate the corneal epitheliotropic abilities of two commercialized human platelet lysates (HPLs) and to compare the results with other blood derivatives, including human peripheral serum (HPS) and bovine fetal serum (FBS).

METHODS

In vitro, human corneal epithelial cells were incubated in various concentrations (0%, 3%, 5% and 10%) of blood derivatives. Two commercialized HPLs, including UltraGRO TM (Helios, Atlanta, GA) and PLTMax (Mill Creek, Rochester, MI), were tested and compared with HPS and FBS. Scratch-induced directional wounding assay was performed to evaluate cellular migration. MTS assay was used to evaluate cellular proliferation. Cellular differentiation was examined by scanning electron microscopy, inverted microscopy and transepithelial electrical resistance. Sprague-Dawley rats were used to evaluate the effects of the blood derivatives on corneal epithelial wound healing in vivo. Different blood derivatives were applied topically every 2 hours for 2 days after corneal epithelial debridement. The concentrations of epidermal growth factor (EGF), transforming growth factor -β1 (TGF-β1), fibronectin, platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, and hyaluronic acid in different blood derivatives were evaluated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

In vitro experiments demonstrated statistically comparable epitheliotropic characteristics in cellular proliferation, migration, and differentiation for the two commercialized HPLs compared to FBS and HPS. Cells cultured without any serum were used as control group. The epitheliotropic capacities were statistically higher in the two commercialized HPLs compared to the control group (p<0.05). Among the different concentrations of blood derivatives, the preparations with 3% yielded better outcomes compared to 5% and 10%. In rats, HPLs also caused improved but not statistically significant wound healing compared to HPS. All the blood derivatives had better wound healing ratios than the control group (p<0.05). In the quantification of epitheliotropic factors, UltraGRO and PLTMax had significantly higher levels of EGF, TGF- β1, fibronectin than human peripheral serum (p<0.05).

CONCLUSIONS

Both commercialized HPLs showed comparable corneal epitheliotropic abilities and wound healing rates compared to HPS and FBS in the in vivo and in vitro studies. Our results suggest that HPLs may have the potential to replace HPS in the treatment of corneal epithelial problems.

Serum components and clinical efficacies of autologous serum eye drops in dry eye patients with active and inactive Sjogren syndrome

PURPOSE:

Autologous serum eye drops are considered safe and efficient for the treatment of various ocular surface disorders, including dry eye diseases (DED) caused by the primary and secondary Sjogren syndrome (SS). However, the serum components in patients of SS may be different from those of normal patients and can thus lead to unpredictable therapeutic effects. This study divided the SS patients into active and inactive types based on the erythrocyte sedimentation rate and the presence or absence of active rheumatoid arthritis.

METHODS:

We compared the serum components of these two groups with standard and multiplex enzyme linked immunosorbent assay arrays and predicted the therapeutic effects of topical autologous serum for the treatment of DED with ocular surface disease index (OSDI) and Oxford Schema scale (OSS).

RESULTS:

Hyaluronic acid and transforming growth factor b1 levels were significantly higher in the active SS group compared to the inactive SS group (P < 0.01), whereas epidermal growth factors, insulin growth factor 1, and fibroblast growth factor b had no significant differences between these two groups. Active SS group had significantly higher expressions of interleukin (IL) 1 beta, IL 6, and tumor necrosis factor alpha compared to inactive SS patients (P < 0.05). There were no statistical differences in therapeutic effects between these two groups, as measured with the OSDI or OSS.

CONCLUSION:

Dividing the Sjogren dry eye patients into active and inactive groups may appear as a reasonable method to predict the quality of autologous serum eye drops, but there seems to be no significant predictability to the therapeutic effects.