Pharmacokinetic evaluation of topical calcineurin inhibitors for treatment of allergic conjunctivitis

Efficacy and Safety of 0.1% Cyclosporine versus 2% Cyclosporine in the Treatment of Severe Vernal Keratoconjunctivitis in Children

INTRODUCTION

Vernal keratoconjunctivitis (VKC) is an inflammatory condition in children that can cause severe eye complications. Treatment is based on corticosteroid therapy during flare-ups, then antihistamines and cyclosporine in calmer periods. The dosage and posology of cyclosporine are subject to debate.

METHODS

The aim of the study is to compare the evolution in symptomatic and clinical scores, and need for topical corticosteroid treatment in a population of children with severe VKC treated with two dosages of cyclosporine treatment (0.1% and 2%). Data were compiled on inclusion then every three months from March, with a total follow-up duration of 12 months. Data concerning patient evolutions and complications were collected for the two treatment groups.

RESULTS

The mean age of the 46 children was 8.8 ±2.4 years with age at onset of symptoms of 5.1 ± 0.9 years. The cohort was predominantly (65%) male. Corticosteroid dependence on inclusion was present in 52% of the children included. A significant improvement in the various symptomatic and clinical scores was observed following treatment with cyclosporine (0.1% and 2%). Use of topical corticosteroid treatment reduced from 19 drops per month on inclusion to 4 drops per month at 12 months. Safety was comparable for the two groups.

CONCLUSION

Treatments with cyclosporine 0.1% and 2% lead to a favourable evolution in clinical and symptomatic scores and reduced corticosteroid use. Cyclosporine 0.1% is an interesting alternative to the 2% dosage, particularly due to its availability and ease of handling.

Executive summary: Japanese guidelines for allergic conjunctival diseases 2021

Allergic conjunctival disease (ACD) is an inflammatory disease of the conjunctiva that is mainly caused by type I hypersensitivity response to allergens and accompanied by subjective symptoms and other findings induced by antigens. ACD is classified as allergic conjunctivitis, atopic keratoconjunctivitis, vernal keratoconjunctivitis, and giant papillary conjunctivitis. This article summarizes the third edition of the Japanese guidelines for allergic conjunctival diseases published in 2021 and outlines the diagnosis, pathogenesis, and treatment of ACD. Since the introduction of immunosuppressive eye drops, the treatment strategies for severe ACDs have significantly changed. To clarify the recommended standard treatment protocols for ACD, the advantages and disadvantages of these treatments were assessed using clinical questions, with a focus on the use of steroids and immunosuppressive drugs. This knowledge will assist healthcare providers and patients in taking an active role in medical decision making.

Therapeutic efficacy of tacrolimus in vernal keratoconjunctivitis: a meta-analysis of randomised controlled trials

Background and objective

Tacrolimus has been widely used in recent years for treating allergic conjunctivitis, but there is currently no available meta-analysis regarding its therapeutic efficacy. This study systematically evaluated the effectiveness of tacrolimus in the treatment of allergic conjunctivitis.

Methods

Data obtained from literature searches of the PubMed, Cochrane Library, Embase, CNKI, and Wanfang databases were retrieved by combining medical subject words and free words. Literature was selected on the basis of established inclusion and exclusion criteria, and the extracted data were evaluated for risk of bias using RevMan 5.3 for meta-analysis.

Results

A total of 177 articles were retrieved, of which 5 articles were eventually selected, all of which involved tacrolimus treatment for vernal keratoconjunctivitis. A total of 203 samples were analysed. Results of the meta-analysis showed that the tacrolimus treatment group had significantly lower ocular objective sign scores (SMD −1.39, 95% CI −2.50 to −0.27; p<0.05) and had a significantly lower subjective symptom evaluation score (SMD −0.92, 95% CI −1.59 to −0.24; p<0.05) than the control group.

Conclusion

Current evidence shows that tacrolimus is effective in treating vernal keratoconjunctivitis.

Emerging Therapeutics for Ocular Surface Disease

PURPOSE OF REVIEW

The purpose of this article is to review treatment advances in ocular allergy that include the treatment of the various signs and symptoms of the allergic inflammatory response of the ocular surface.

RECENT FINDINGS

Recent studies have demonstrated improved pharmacological effect of topical agents with artificial tears and cold compresses; brimonidine, a new ophthalmic decongestant which has demonstrated decreased rebound conjunctivitis; and potential use of contact lens and other novel delivery instruments to increase medication retention time. Currently, there have been limited advances in novel ophthalmic treatments. Non-pharmacological interventions have demonstrated in a randomized control study that artificial tears and the use cold compresses alone or in combination with ophthalmic antihistamines can enhance the effectiveness of a traditional pharmacological therapy. The primary advances have been the start of head-to-head studies comparing various agents actively being used in the treatment of ocular allergy. In addition, there has been increasing interest in the development of novel delivery systems to increase residence time of pharmacological agents in the ocular surface such as nanoparticles, microfilms; examining novel pathways of controlling the allergic inflammatory response of the ocular surface such as modulation of cytokines, transcription factors, and immunophilins.

The Immunosuppressant Macrolide Tacrolimus Activates Cold-Sensing TRPM8 Channels

TRPM8 is a polymodal, nonselective cation channel activated by cold temperature and cooling agents that plays a critical role in the detection of environmental cold. We found that TRPM8 is a pharmacological target of tacrolimus (FK506), a macrolide immunosuppressant with several clinical uses, including the treatment of organ rejection following transplants, treatment of atopic dermatitis, and dry eye disease. Tacrolimus is an inhibitor of the phosphatase calcineurin, an action shared with cyclosporine. Tacrolimus activates TRPM8 channels in different species, including humans, and sensitizes their response to cold temperature by inducing a leftward shift in the voltage-dependent activation curve. The effects of tacrolimus on purified TRPM8 in lipid bilayers demonstrates conclusively that it has a direct gating effect. Moreover, the lack of effect of cyclosporine rules out the canonical signaling pathway involving the phosphatase calcineurin. Menthol (TRPM8-Y745H)- and icilin (TRPM8-N799A)-insensitive mutants were also activated by tacrolimus, suggesting a different binding site. In cultured mouse DRG neurons, tacrolimus evokes an increase in intracellular calcium almost exclusively in cold-sensitive neurons, and these responses were drastically blunted in Trpm8 KO mice or after the application of TRPM8 antagonists. Cutaneous and corneal cold thermoreceptor endings are also activated by tacrolimus, and tacrolimus solutions trigger blinking and cold-evoked behaviors. Together, our results identify TRPM8 channels in sensory neurons as molecular targets of the immunosuppressant tacrolimus. The actions of tacrolimus on TRPM8 resemble those of menthol but likely involve interactions with other channel residues.SIGNIFICANCE STATEMENT TRPM8 is a polymodal TRP channel involved in cold temperature sensing, thermoregulation, and cold pain. TRPM8 is also involved in the pathophysiology of dry eye disease, and TRPM8 activation has antiallodynic and antipruritic effects, making it a prime therapeutic target in several cutaneous and neural diseases. We report the direct agonist effect of tacrolimus, a potent natural immunosuppressant with multiple clinical applications, on TRPM8 activity. This interaction represents a novel neuroimmune interface. The identification of a clinically approved drug with agonist activity on TRPM8 channels could be used experimentally to probe the function of TRPM8 in humans. Our findings may explain some of the sensory and anti-inflammatory effects described for this drug in the skin and the eye surface.

In vitro study of cyclosporine A 0.05 % on primary and recurrent pterygium fibroblasts

To compare the cyclosporine 0.05 % exposure effect on fibroblasts from primary and recurrent pterygium. Primary culture of fibroblasts from primary and recurrent pterygium was performed until the third passage, which was exposed to cyclosporine 0.05 % in a group and the other remaining unexposed (control group), in triplicates. After 3, 6, 12, and 17 days of exposure the viable cell counting was performed by hemocytometer. The results were statistically analyzed using the technique of analysis of non-parametric variance model for repeated measures with three factors. There was a significant reduction in both fibroblast proliferation, in primary as in the recurrent pterygium cultures exposed to cyclosporine when compared not exposed cultures, with statistical significance (P < 0.05). Comparing primary and recurrent pterygium that received the drug, there was no significant difference in cell proliferation in relation to primary or recurrent pterygium. Cyclosporine 0.05 % is effective in inhibiting fibroblast proliferation in culture, both in primary and as in recurrent pterygium.