thymosin-beta(4) and Dry-Eye-Syndromes

Thymosin beta 4 (Tβ4) has important applications in ocular repair and Phase 3 clinical trials using Tβ4 to treat dry eye and neurotrophic keratopathy are currently ongoing. These exciting clinical possibilities for Tβ4 in the eye are the result of seminal basic scientific discoveries and contributions from so many talented investigators. Areas covered: My personal Tβ4 journey began at the NIH in 1998 and propelled my career as a clinician scientist. As a tribute to the amazing individuals who have guided and supported me along with my brilliant colleagues and students who have contributed and collaborated with me over the years, this review will tell the cumulative story of how Tβ4 became a major potential new therapy for corneal wound healing disorders. The journey has been marked by the thrilling exhilaration from fundamental breakthroughs in the laboratory and clinic, combined with the challenging and often harsh realities of submitting grants and obtaining funding. Expert opinion: The electrifying possibility of Tβ4 as a revolutionary novel dry eye therapy is something that could have only been dreamed about just a few years ago. We believe that Tβ4 eyedrops will help many patients suffering from several ocular surface related disorders.

Topics: Animals; Corneal Diseases; Corneal Keratocytes; Dry Eye Syndromes; Eye; Humans; Ocular Physiological Phenomena; Thymosin; Translational Research, Biomedical; Wound Healing

Chronic ocular surface diseases such as dry eye, blepharitis, and neurotrophic keratopathies represent a significant and a growing therapeutic challenge. The basis of this expanding prevalence is multifactorial and may due to issues such as an aging population, an increasing use of video display terminals, and increases in frequency of refractive surgeries. The growing incidence of diseases such as diabetes may also be a contributing factor. Current treatments for ocular surface disease include artificial tears, lubricants, tear duct plugs, steroids, antibiotics, cyclosporine, scleral lenses, and serum tears. Treatment choices depend on the type and severity of the disease, but in general positive outcomes are limited because many of these treatments do not fully address the underlying disease process or promote mechanisms that facilitate long-term wound repair. From minor corneal injuries to more severe inflammatory-mediated pathologies, clinicians need agents that promote corneal healing and reduce the inflammatory response to prevent visual disturbances and improve quality of life. A focus on treatments that reduce the inflammatory responses while accelerating corneal epithelial growth would represent a major step forward from current treatment options. Increasing evidence suggests that thymosin beta 4 (Tβ4), a naturally occurring polypeptide, can elicit this spectrum of therapeutic responses: a rapid corneal reepithelialization and a reduction in corneal inflammation. This chapter serves as a review of standard therapies as well as recent advancements in the development of newer therapies that includes the use of Tβ4 that is proving to be an exciting new agent for the management of ocular surface disease.

Topics: Animals; Anti-Inflammatory Agents; Corneal Diseases; Disease Models, Animal; Dry Eye Syndromes; Humans; Thymosin; Wound Healing

Dry eye disorders are becoming more common due to many causes, including an aging population, increased pollution, and postrefractive surgery. Current treatments include artificial tears; gels; lubricants; tear duct plugs; and anti-inflammatory agents such as steroids, doxycycline, and cyclosporine. For more severe forms of the disease, serum tears and scleral contact lenses are employed. Despite these therapies, successful resolution of the problem is limited because none of these treatments fully addresses the underlying causes of dry eye to promote ocular surface repair. Thymosin β4 (Tβ4), a small, naturally occurring protein, promotes complete and faster corneal healing than saline alone or prescription agents (doxycycline and cyclosporine) in various animal models of eye injury. In human trials, it improves both the signs and symptoms of moderate to severe dry eye with effects lasting beyond the treatment period. This review will cover the multiple activities of Tβ4 on cell migration, inflammation, apoptosis, cytoprotection, and gene expression with a focus on mechanisms of cell migration, including laminin-332 synthesis and degradation, that account for this paradigm-shifting potential new treatment for dry eye disorders. We will also speculate on additional mechanisms that might promote eye repair based on data from other tissue injury models. Such studies provide the rationale for use of Tβ4 in other types of eye disorders beyond dry eye. Finally, we will identify the gaps in our knowledge and propose future research avenues.

Topics: Animals; Dry Eye Syndromes; Eye Injuries; Humans; Thymosin; Wound Healing

The purpose of this manuscript is to review the clinical entity of dry eye syndrome (DES) and to provide a scientific basis and rationale for the usage of thymosin beta 4 (Tβ4) as a novel therapy for DES. DES is a common disorder affecting an estimated 25-30 million people in the United States alone and is characterized by inflammation of the ocular surface. Consequently, patients can suffer from burning, irritation, severe discomfort, foreign body sensation, and blurry and decreased vision. Recent animal studies of DES demonstrate that Tβ4 eye drops significantly reduce corneal fluorescein staining, indicating improved wound healing. Based on previous studies, there is clear support for further clinical investigation and development of Tβ4 as a novel, safe, and effective agent to treat dry eye. Herein, we discuss the scientific and clinical rationales that make Tβ4 a potential ideal candidate therapeutic for DES.

Topics: Animals; Cornea; Dry Eye Syndromes; Humans; Thymosin; Wound Healing

Standard therapies for severe dry eye are limited and fail to resolve the problem. The purpose of this study was to evaluate the safety and efficacy of Thymosin β4 eye drops (RGN-259) as a novel therapy for severe dry eye disease (including that associated with graft vs. host disease).. A small, multicenter, randomized, double-masked, placebo-controlled 56-day phase 2 clinical trial including a 28-day follow-up at 2 US sites. Nine patients with severe dry eye were treated with either RGN-259 (0.1%) or vehicle control 6 times daily over a period of 28 days. Dry eye sign and symptom assessments, such as ocular discomfort (using the OSDI questionnaire) and corneal fluorescein staining (using the NEI workshop grading system), were evaluated at various time points.. Statistically significant differences in both symptom and sign assessments, were seen at various time points throughout the study. Of particular note at day 56, the RGN-259-treated group (12 eyes) had 35.1% reduction of ocular discomfort compared with vehicle control (6 eyes) (P = 0.0141), and 59.1% reduction of total corneal fluorescein staining compared with vehicle control (P = 0.0108). Other improvements seen in the RGN-259-treated patients included tear film breakup time and increased tear volume production.. In this small trial, RGN-259 eye drops were safe and well tolerated and met key efficacy objectives with statistically significant symptom and sign improvements, compared with vehicle control, at various time intervals, including 28-days posttreatment. CLINICAL TRIAL REGISTRATION--URL: http://www.clinicaltrials.gov. Unique identifier: NCT01393132.

Topics: Adult; Aged; Cornea; Double-Blind Method; Dry Eye Syndromes; Female; Fluorescein; Fluorescent Dyes; Fluorophotometry; Follow-Up Studies; Graft vs Host Disease; Humans; Male; Microfilament Proteins; Middle Aged; Ophthalmic Solutions; Surveys and Questionnaires; Tears; Thymosin

We investigated the therapeutic effect of recombinant thymosin β4 (rTβ4) on rabbit autoimmune dacryoadenitis, an animal model of SS dry eye, and explore its mechanisms.. Rabbits were treated topically with rTβ4 or PBS solution after disease onset for 28 days, and clinical scores were determined by assessing tear secretion, break-up time, fluorescein, hematoxylin and eosin staining, and periodic acid-Schiff. The expression of inflammatory mediators in the lacrimal glands were measured by real-time PCR. The expression of T helper 17 (Th17) cell-related transcription factors and cytokines were detected by real-time PCR and Western blotting. The molecular mechanism underlying the effects of rTβ4 on Th17 cell responses was investigated by Western blotting.. Topical administration of rTβ4 after disease onset efficiently ameliorated the ocular surface inflammation and relieved the clinical symptoms. Further analysis revealed that rTβ4 treatment significantly inhibited the expression of Th17-related genes (RORC, IL-17A, IL-17F, IL-1R1, IL-23R, and granulocyte-macrophage colony-stimulating factor) and IL-17 protein in lacrimal glands, and meanwhile decreased the inflammatory mediators expression. Mechanistically, we demonstrated that rTβ4 repressed the phosphorylation of signal transducer and activator of transcription 3 (STAT3) both in vivo and in vitro. Activation of the STAT3 signal pathway by Colivelin partly reversed the suppressive effects of rTβ4 on IL-17 expression in vitro.. rTβ4 could alleviate ongoing autoimmune dacryoadenitis in rabbits, probably by suppressing Th17 response via partly affecting the STAT3 pathway. These data may provide a new insight into the therapeutic effect and mechanism of rTβ4 in dry eye associated with Sjögren's syndrome.

Topics: Animals; Dacryocystitis; Disease Models, Animal; Dry Eye Syndromes; Interleukin-17; Rabbits; Tears; Th17 Cells

Dry eye disease (DED) is a multifactorial ocular disorder that interferes with daily living and reduces quality of life. However, there is no most ideal therapeutic treatment to address all the deleterious defects of DED. The purpose of this study was to investigate the ability of recombinant human thymosin β4 (rhTβ4) to promote healing in a benzalkonium chloride (BAC)-induced mice DED model and the anti-inflammatory effects involved in that process. Eye drops consisting of 0.05% and 0.1% rhTβ4 were used for treatment of DED. Tear volume and corneal staining scores were measured after 7 days. Periodic acid-Schiff staining for gobleT cells in conjunctiva, immunohistochemical staining for CD4

Topics: Animals; Anti-Inflammatory Agents; Benzalkonium Compounds; Cytokines; Disease Models, Animal; Dry Eye Syndromes; Humans; Mice; NF-kappa B; Ophthalmic Solutions; Quality of Life; Thymosin

Thymosin β4 (Tβ4) is a multifunctional N-acetylated peptide with distinct activities important at various stages. Due to its potential multiple therapeutic uses in many fields, there is an increasing need of Tβ4 at lower costs than with the use of chemical synthesis. In this research, we developed a method to produce rhTβ4 with N-acetylation in E. coli. Firstly, the E. coli strain whose chromosome being integrated by the specific N-terminal acetyltransferase ssArd1 was constructed. Secondly, the rhTβ4-Intein was constructed, in which rhTβ4 was fused to the N-terminus of the smallest mini-intein Spl DnaX. The rhTβ4 could be fully acetylated when the rhTβ4-Intein was expressed in the engineering strain. After purification, the rhTβ4-Intein fusion protein was induced with dithiothreitol (DTT) to release rhTβ4 through intein-mediated N-terminal cleavage. Under the optimal conditions, the N-terminal serine residue was shown to be 100% acetylated and the yield of N-acetylated rhTβ4 can reach 200 mg per litre. The N-acetylated rhTβ4 could be stable at 2-8 °C for 24 months in PBS buffer without protein degradation and concentration change. The N-acetylated rhTβ4 also showed the activity of binding with actins from different sources and excellent therapeutic effect on the rats with moderate to severe dry eye disease.

Topics: Acetylation; Animals; Disease Models, Animal; Dry Eye Syndromes; Escherichia coli; Female; Humans; Rats; Rats, Wistar; Recombinant Fusion Proteins; Thymosin

This study evaluated the clinical activity of RGN-259 (thymosin β4) in comparison with cyclosporine A (CsA), diquafosol (DQS), and lifitegrast (LFA) in a murine model of dry eye. The model was NOD.B10-H2

Topics: Animals; Conjunctiva; Cornea; Cyclosporine; Disease Models, Animal; Dry Eye Syndromes; Female; Goblet Cells; Humans; Inflammation Mediators; Lacrimal Apparatus; Male; Mice; Mice, Inbred NOD; Mucins; Ophthalmic Solutions; Phenylalanine; Polyphosphates; Prescription Drugs; Scopolamine; Sulfones; Tears; Thymosin; Treatment Outcome; Uracil Nucleotides

Dry eye syndrome is a common condition that affects up to 20% of the population aged 45 and older. There are no successful treatments to date. The goal of this research was to determine the efficacy of various doses and the optimal frequency of thymosin β4 (Tβ4) treatment in a murine severe dry eye model.. The study was performed using a controlled adverse environment chamber (CAE) in combination with scopolamine to induce moderate to severe dry eye in mice. The study included five mice per group and tested six different doses of Tβ4 twice per day for 12 days. Tβ4 at 0.1% was also administered 2 - 4 times per day for 12 days. Healing was measured by fluorescein staining.. Tβ4 significantly reduced the signs of dry eye relative to controls. The treatment effect was more pronounced than the positive controls, doxycycline and Restasis (cyclosporine 0.05%). Active doses of 0.1 and 0.5% were determined, and it was found that the frequency of dosing at 2 times per day was the most effective for healing.. Tβ4 has the potential to be an important new effective therapeutic for dry eye.

Topics: Administration, Topical; Animals; Cyclosporine; Disease Models, Animal; Dose-Response Relationship, Drug; Dry Eye Syndromes; Environment, Controlled; Female; Humans; Mice; Mice, Inbred C57BL; Ophthalmic Solutions; Thymosin; Wound Healing