Subconjunctival sirolimus in the treatment of autoimmune non-necrotizing anterior scleritis: results of a phase I/II clinical trial

The mTOR signalling in corneal diseases: A recent update

Corneal diseases affect 4.2 million people worldwide and are a leading cause of vision impairment and blindness. Current treatments for corneal diseases, such as antibiotics, steroids, and surgical interventions, have numerous disadvantages and challenges. Thus, there is an urgent need for more effective therapies. Although the pathogenesis of corneal diseases is not fully understood, it is known that injury caused by various stresses and postinjury healing, such as epithelial renewal, inflammation, stromal fibrosis, and neovascularization, are highly involved. Mammalian target of rapamycin (mTOR) is a key regulator of cell growth, metabolism, and the immune response. Recent studies have revealed that activation of mTOR signalling extensively contributes to the pathogenesis of various corneal diseases, and inhibition of mTOR with rapamycin achieves promising outcomes, supporting the potential of mTOR as a therapeutic target. In this review, we detail the function of mTOR in corneal diseases and how these characteristics contribute to disease treatment using mTOR-targeted drugs.

Pharmacokinetics of Sirolimus in a Novel Liposome Delivery System in Selected Ocular Tissues and Plasma Following a Single Subconjunctival Injection in Dutch Belted Rabbits

Purpose: To determine the pharmacokinetics of a proprietary liposomal sirolimus (LS) formulation in ocular tissues and plasma following a single subconjunctival (SCJ) injection in Dutch belted rabbits (DBR). Analytical methods for detection of LS in plasma, aqueous humor (AH), vitreous humor (VH), retina, combined retina/choroid/retinal pigment epithelium, sclera, and iris/ciliary body were developed to examine samples. Methods: Thirty male DBR were subconjunctivally injected in both eyes with 0.1 mL of LS of 1,000 μg/mL. At selected times post-injection, ocular tissues and whole blood samples were obtained. Sirolimus concentrations were measured using liquid chromatography/tandem mass spectrometry. Results: No LS was detected in serum or AH at any time. All other examined ocular tissues had quantifiable amounts of LS at all times. LS levels were highest in sclera and lowest in VH, suggesting LS followed the supraciliary and suprachoroidal spaces to reach the posterior segment. Vitreous peak of sirolimus levels occurred at 2 h, and the sclera adjacent to the injection peaked at both 2 and 96 h. LS levels in remaining ocular tissues peaked at 6 h and decreased with time, persisting at presumed therapeutic levels on day 22. Conclusions: LS can quickly diffuse into posterior intraocular tissues after SCJ injection without reaching quantifiable levels in AH or serum in DBR. Peak levels occurred in posterior intraocular tissues at 6 h and persisted in all tissues after 3 weeks. SCJ LS in DBR is safe, has a stable pharmacokinetic profile, and should be considered for further study in human trials for autoimmune ophthalmopathies.

Management of noninfectious scleritis

Scleritis is a manifestation of inflammatory eye disease that involves the sclera. It can be divided into multiple subtypes, including diffuse anterior, nodular anterior, necrotizing, and posterior scleritis. In many cases, scleritis is restricted to the eye; however, it can occur in the context of systemic illness, particularly autoimmune and infectious conditions. Patients with autoimmune conditions, such as rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, and polyangiitis with granulomatosis, may develop scleritis flares that may require topical and systemic therapy. Initial therapy typically involves oral nonsteroidal anti-inflammatory drugs (NSAIDs); however, it is important to address the underlying condition, particularly if systemic. Other treatment regimens typically involve either local or systemic steroids or the use of immunomodulatory agents, which have a wide range of efficacy and documented use in the literature. There is a myriad of immunomodulatory agents used in the treatment of scleritis including antimetabolites, calcineurin inhibitors, biologics, and alkylating agents. In this review, we highlight the various subtypes of noninfectious scleritis and explore each of the mainstay agents used in the management of this entity. We explore the use of steroids and NSAIDs in detail and discuss evidence for various immunomodulatory agents.

Rheumatoid Arthritis Associated Episcleritis and Scleritis: An Update on Treatment Perspectives

Episcleritis and scleritis are the most common ocular inflammatory manifestation of rheumatoid arthritis. Rheumatoid arthritis (RA) accounts for 8% to 15% of the cases of scleritis, and 2% of patients with RA will develop scleritis. These patients are more likely to present with diffuse or necrotizing forms of scleritis and have an increased risk of ocular complications and refractory scleral inflammation. In this review we provide an overview of diagnosis and management of rheumatoid arthritis-associated episcleritis and scleritis with a focus on recent treatment perspectives. Episcleritis is usually benign and treated with oral non-steroidal anti- inflammatory drugs (NSAIDs) and/or topical steroids. Treatment of scleritis will classically include oral NSAIDs and steroids but may require disease-modifying anti-rheumatic drugs (DMARDs). In refractory cases, treatment with anti TNF biologic agents (infliximab, and adalimumab) is now recommended. Evidence suggests that rituximab may be an effective option, and further studies are needed to investigate the potential role of gevokizumab, tocilizumab, abatacept, tofacitinib, or ACTH gel. A close cooperation is needed between the rheumatology or internal medicine specialist and the ophthalmologist, especially when scleritis may be the first indicator of an underlying rheumatoid vasculitis.

Toxicity Evaluation of a Novel Rapamycin Liposomal Formulation After Subconjunctival and Intravitreal Injection

Purpose: Safety and toxicity evaluation of a novel, liposome-encapsulated rapamycin formulation, intended for autoimmune ocular disorders. Methods: The formulation was assessed by micronucleus polychromatic erythrocyte production, irritability by Hen's Egg Test-Chorioallantoic Membrane (HET CAM), sterility, and pyrogenicity testing. Subconjunctival (SCJ) and intravitreal (IVT) administration of the formulation were performed to evaluate subacute and acute toxicity, respectively. Differences between groups in biochemical and hematological parameters were evaluated by analysis of variance and t-tests. Numeric score was assigned to histopathological classification. Electroretinography (ERG) testing was also performed. Data were analyzed by a 1 way no parametric Kruskal-Wallis and the Mann-Whitney tests. Significance was considered when P < 0.05. Results: No significant toxicity directly related to the preparation was detected. Micronucleus count, mucous irritation score, and pyrogenicity results were negative. Pathology demonstrated no damage related to the formulation after SCJ injection. After IVT injection, only lens injury associated with technique was observed. Retinal function was also conserved in ERG. Conclusions: The preparation evaluated offers a good toxicity and safety profile when injected in a SCJ or IVT manner in an animal model. A clinical trial conducted in humans is highly warranted, as it could reveal an alternative immunosuppressive treatment for ophthalmological immune-mediated pathologies.

Remission of Non-Infectious Anterior Scleritis: Incidence and Predictive Factors

PURPOSE

To assess how often non-infectious anterior scleritis remits and identify predictive factors.

METHODS

Our retrospective cohort study at four ocular inflammation subspecialty centers collected data for each affected eye/patient at every visit from center inception (1978, 1978, 1984, 2005) until 2010. Remission was defined as inactivity of disease off all suppressive medications at all visits spanning at least three consecutive months or at all visits up to the last visit (to avoid censoring patients stopping follow-up after remission). Factors potentially predictive of remission were assessed using Cox regression models.

RESULTS

During 1,906 years' aggregate follow-up of 832 affected eyes, remission occurred in 214 (170 of 584 patients). Median time-to-remission of scleritis = 7.8 years (95% confidence interval [CI]: 5.7, 9.5). More remissions occurred earlier than later during follow-up. Factors predictive of less scleritis remission included scleritis bilaterality (adjusted hazard ratio [aHR] = 0.46, 95% CI: 0.32-0.65); and diagnosis with any systemic inflammatory disease (aHR = 0.36, 95% CI: 0.23-0.58), or specifically with Rheumatoid Arthritis (aHR = 0.22), or Granulomatosis with Polyangiitis (aHR = 0.08). Statin treatment (aHR = 1.53, 95% CI: 1.03-2.26) within ≤90 days was associated with more remission incidence.

CONCLUSIONS

Our results suggest scleritis remission occurs more slowly in anterior scleritis than in newly diagnosed anterior uveitis or chronic anterior uveitis, suggesting that attempts at tapering suppressive medications is warranted after long intervals of suppression. Remission is less frequently achieved when systemic inflammatory diseases are present. Confirmatory studies of whether adjunctive statin treatment truly can enhance scleritis remission (as suggested here) are needed.

New therapies in development for the management of non-infectious uveitis: A review

Uveitis is a spectrum of inflammatory disorders characterized by ocular inflammation and is one of the leading causes of preventable visual loss. The main aim of the treatment of uveitis is to control the inflammation, prevent recurrences of the disease and preserve vision while minimizing the adverse effects associated with the therapeutic agents. Initial management of uveitis relies heavily on the use of corticosteroids. However, monotherapy with high-dose corticosteroids is associated with side effects and cannot be maintained long term. Therefore, steroid-sparing agents are needed to decrease the burden of steroid therapy. Currently, the therapeutic approach for non-infectious uveitis (NIU) consists of a step-ladder strategy with the first-line option being corticosteroids in various formulations followed by the use of first-, second- and third-line agents in cases with suboptimal steroid response. Unfortunately, the agents currently at our disposal have limitations such as having a narrow therapeutic window along with their own individual potential side-effect profiles. Therefore, research has been targeted to identify newer drugs as well as new uses for older drugs that target specific pathways in the inflammatory response. Such efforts are made in order to provide targeted and safer therapy with reduced side effects and greater efficacy. Several specially designed molecular antibodies are currently in various phases of investigations that can potentially halt the inflammation in patients with NIU. In the review, we have provided a comprehensive overview of the current and upcoming therapeutic options for patients with NIU.

Safety and efficacy of tacrolimus-coated silicone plates as an alternative to mitomycin C in a rabbit model of conjunctival fibrosis

Purpose

To find safer and more effective drugs than mitomycin C to prevent conjunctival fibrosis in a rabbit model.

Methods

Twenty-four rabbits were involved and randomly divided into four groups. Limbus-based peritomy was performed at the superior cornea, and normal saline (NS group), mitomycin C (MMC group), SR (SR group), or TC (TC group)-coated silicone plate was inserted at the sub-Tenon’s space in each group. Conjunctival congestion was evaluated at 1 and 4 weeks postoperatively. At 4 weeks, the numbers of inflammatory cells, fibroblasts, myofibroblasts, blood vessels, and goblet cells were counted in the conjunctiva and Tenon’s capsule around the silicone plate.

Results

At 4 weeks, conjunctival congestion was significantly less than that observed at 1 week in the SR and TC groups (p < 0.05), whereas the number of myofibroblasts was significantly lower in the MMC and TC groups (p < 0.05). The conjunctiva was significantly less congested in the TC group versus the other groups at 1 week and 4 weeks (p < 0.05). The TC group had the lowest number of inflammatory cells and MMC group had the lowest number of goblet cells among all groups (p < 0.05).

Conclusions

The TC-coated silicone plate was more effective in inhibiting inflammation and fibrosis versus the MMC-coated silicone plate and was associated with fewer adverse effects in the rabbit model.

Ocular Manifestations of Rheumatoid Arthritis: Implications of Recent Clinical Trials

While rheumatoid arthritis (RA) typically presents with synovitis of the small and medium joints of the hands, ocular manifestations of the disease are generally overlooked and largely underdiagnosed. These complications usually present in longstanding RA population and occasionally represents the first manifestation of the disease and generally affect the anterior chamber of the eye, leading to keratoconjunctivitis sicca, episcleritis, scleritis, peripheral ulcerative keratitis and anterior uveitis. In this review, we present the current understanding of the pathophysiologic mechanisms for ocular disease in RA, including the role of oxidative stress, cytokine imbalance, chronic inflammation, vascular permeability, immune complex deposition and the role of T-cells as well as the contribution of tear hyperosmolarity among other factors. We also discuss the clinical presentation and diagnosis of each of the ocular disease entities highlighting the latest strategies in the management of this serious disorders that could potentially lead to blindness and the implications of recently completed and ongoing clinical trials in the field. While RA disease control is the cornerstone in the management of RA-associated ocular manifestations, early recognition of ocular pathology with prompt referral to ophthalmology is of paramount importance in order to prevent blindness and improve the quality of life in this patient population.

[Scleritis and systemic diseases: What should know the internist?]

Scleritis is an inflammatory disease of the sclera; outer tunic of the eye on which the oculomotor muscles are inserted. It can be associated with a systemic disease up to one time out of 3. These associated diseases are mainly rheumatoid arthritis, vasculitis, including granulomatosis with polyangiitis in the first line and spondyloarthropathies. Before mentioning such an etiology, it is necessary to eliminate an infectious cause, mainly herpetic, which is regularly underestimated. The classification of scleritis is clinical. We distinguish between anterior scleritis and posterior scleritis. Anterior scleritis is diffuse or nodular, usually of good prognosis. Anterior necrotizing scleritis with inflammation is often associated with an autoimmune disease, necrotizing scleritis without inflammation usually reflects advanced rheumatoid arthritis. The treatment of these conditions requires close collaboration between internists and ophthalmologists to decide on the use of corticosteroid therapy with or without immunosuppressors or biotherapies.

Rapamycin Eye Drops Suppress Lacrimal Gland Inflammation In a Murine Model of Sjögren's Syndrome

Purpose

To evaluate the efficacy of topical rapamycin in treating autoimmune dacryoadenitis in a mouse model of Sjögren's syndrome.

Methods

We developed rapamycin in a poly(ethylene glycol)-distearoyl phosphatidylethanolamine (PEG-DSPE) micelle formulation to maintain solubility. Rapamycin or PEG-DSPE eye drops (vehicle) were administered in a well-established Sjögren's syndrome disease model, the male nonobese diabetic (NOD) mice, twice daily for 12 weeks starting at 8 weeks of age. Mouse tear fluid was collected and tear Cathepsin S, a putative tear biomarker for Sjögren's syndrome, was measured. Lacrimal glands were retrieved for histological evaluation, and quantitative real-time PCR of genes associated with Sjögren's syndrome pathogenesis. Tear secretion was measured using phenol red threads, and corneal fluorescein staining was used to assess corneal integrity.

Results

Lymphocytic infiltration of lacrimal glands from rapamycin-treated mice was significantly (P = 0.0001) reduced by 3.8-fold relative to vehicle-treated mice after 12 weeks of treatment. Rapamycin, but not vehicle, treatment increased tear secretion and decreased corneal fluorescein staining after 12 weeks. In rapamycin-treated mice, Cathepsin S activity was significantly reduced by 3.75-fold in tears (P < 0.0001) and 1.68-fold in lacrimal gland lysates (P = 0.003) relative to vehicle-treated mice. Rapamycin significantly altered the expression of several genes linked to Sjögren's syndrome pathogenesis, including major histocompatibility complex II, TNF-α, IFN-γ, and IL-12a, as well as Akt3, an effector of autophagy.

Conclusions

Our findings suggest that topical rapamycin reduces autoimmune-mediated lacrimal gland inflammation while improving ocular surface integrity and tear secretion, and thus has potential for treating Sjögren's syndrome–associated dry eye.

Ocular Pharmacology for Scleritis: Review of Treatment and a Practical Perspective

Scleritis is defined as an infectious or noninfectious inflammation of the sclera that can be broadly categorized according to anatomic location (ie, anterior or posterior) and whether the process is necrotizing or non-necrotizing. Treatment for scleritis is dictated by the etiology of the inflammation, with infectious forms requiring treatment of the inciting agent and noninfectious forms requiring treatment of the underlying inflammation with immunosuppression. Pharmacotherapy for noninfectious scleritis can be classified according to delivery route (eg, local or systemic) and mechanism of action (eg, biologic or nonbiologic). This review will briefly summarize the classification scheme for scleritis before reviewing in depth both systemic and local pharmacotherapies that can be used to effectively treat an eye afflicted by either infectious or noninfectious scleritis. Traditional anti-inflammatory agents such as nonsteroidal anti-inflammatory drugs, steroids, and immunomodulatory therapy will be discussed, as well as newer biologic therapies such as antitumor necrosis factor alpha and anti-CD20 agents.