Inhibitory effects of FK506 on the development of experimental allergic/immune-mediated blepharoconjunctivitis in Lewis rats by systemic but not by topical administration

Incremental Concentrations of Tacrolimus Eye Drops as a Strategy for the Management of Severe Vernal Keratoconjunctivitis

Purpose: To assess the effect of different concentrations of tacrolimus eye suspension on the epithelium and stromal keratocytes of human corneas and investigate whether it can be safely used for severe cases of vernal keratoconjunctivitis (VKC).

Methods: Tacrolimus eye suspension was prepared in a range of concentrations of 0.005%, 0.01%, 0.05%, 0.1%, and 0.2%. Molecular analysis was performed ex vivo on human corneas (n = 18), obtained from the eye bank. Transparency and thickness of each cornea were measured while live/dead staining was performed using a triple labeling assay. An incremental concentration approach was then tested on three severe cases of VKC.

Results: All tested tacrolimus concentrations showed no significant changes in corneal thickness or transparency. In corneas treated with 0.1%, rare scattered dead cells were observed, while the folds of corneal surfaces were mostly viable, unlike concentrations higher than 0.1% and lower than 0.05%. Stromal cell densities were highest in the 0.1% tacrolimus treatment condition. Incremental concentrations of tacrolimus suspension were shown to significantly improve VKC cases, where the concentration used for each case depended on the severity of the case.

Conclusions: Topical administration of tacrolimus was not toxic to human corneal cells at all tested concentrations, and the 0.1% concentration has shown the best viability of the corneal tissue. Tacrolimus eye suspension was shown to be safe and effective for use in severe VKC and is proposed as a topical ocular immunosuppressant drug enabling clinicians to incrementally increase the drug concentration according to the clinical severity of the disease to achieve the optimal therapeutic response.

Ocular redness - II: Progress in development of therapeutics for the management of conjunctival hyperemia

Conjunctival hyperemia is one of the most common causes for visits to primary care physicians, optometrists, ophthalmologists, and emergency rooms. Despite its high incidence, the treatment options for patients with conjunctival hyperemia are restricted to over-the-counter drugs that provide symptomatic relief due to short duration of action, tachyphylaxis and rebound redness. As our understanding of the immunopathological pathways causing conjunctival hyperemia expands, newer therapeutic targets are being discovered. These insights have also contributed to the development of animal models for mimicking the pathogenic changes in microvasculature causing hyperemia. Furthermore, this progress has catalyzed the development of novel therapeutics that provide efficacious, long-term relief from conjunctival hyperemia with minimal adverse effects.

Trametinib Attenuates Delayed Rejection and Preserves Thymic Function in Rat Lung Transplantation

Delayed immunological rejection after human lung transplantation causes chronic lung allograft dysfunction, which is associated with high mortality. Delayed rejection may be attributable to indirect alloantigen presentation by host antigen-presenting cells; however, its pathophysiology is not fully understood. The mitogen-activated protein kinase pathway is activated in T cells upon stimulation, and we previously showed that the MEK inhibitor, trametinib, suppresses graft-versus-host disease after murine bone marrow transplantation. We investigated whether trametinib suppresses graft rejection after two types of rat lung transplantation and analyzed its immunological mode of action. Major histocompatibility complex-mismatched transplantation from brown Norway rats into Lewis rats and minor histocompatibility antigen-mismatched transplantation from Fischer 344 rats into Lewis rats were performed. Cyclosporine (CsA) and/or trametinib were administered alone or consecutively. Acute and delayed rejection, lymphocyte infiltration, and pulmonary function were evaluated. Administration of trametinib after CsA suppressed delayed rejection, reduced inflammatory cell infiltration and fibrosis within the graft, and preserved pulmonary functions at Day 28. Trametinib suppressed functional differentiation of T and B cells in the periphery but preserved thymic T cell differentiation. Donor B cells within the graft disappeared by Day 14, indicating that delayed graft rejection at Day 28 was mainly due to indirect presentation by host antigen-presenting cells. Finally, trametinib administration without CsA preconditioning suppressed rejection after minor histocompatibility antigen-mismatched transplantation. Trametinib attenuates delayed rejection upon major histocompatibility complex-mismatched transplantation by suppressing indirect presentation and is a promising candidate to treat chronic lung allograft dysfunction in humans.

Long-term follow-up of tacrolimus ointment for treatment of atopic keratoconjunctivitis

PURPOSE

To evaluate the long-term clinical outcomes of 0.1% tacrolimus dermatologic ointment (Protopic) in cases of refractory atopic keratoconjunctivitis (AKC).

DESIGN

Prospective, nonrandomized, noncontrolled case series.

METHODS

Twenty-two eyes from 11 patients with severe AKC who were treated with 0.1% tacrolimus ointment were followed prospectively. The mean age of the patients was 32.27 ± 12.7 years (range, 19-61 years). Each patient completed a follow-up period of at least 48 months, during which the signs and symptoms of AKC were assessed. Changes in the total scores of signs and symptoms from baseline were recorded at each visit, and the main outcome measure was the clinical response to topical tacrolimus treatment.

RESULTS

Dramatic improvements in clinical signs and symptoms were achieved 1 week after starting topical tacrolimus treatment, and complete clinical resolution was observed in almost all patients 6 weeks after starting treatment. Treatment was gradually reduced, with increasing intervals between applications. Eight patients remained asymptomatic for up to 3 years, although recurrence occurred in 3 patients who attempted to discontinue treatment. All patients complained of a mild burning sensation upon application of the ointment. No additional medications were required to provide relief, and no patient discontinued treatment because of adverse drug effects. No drug-related ocular complications were encountered, and no significant changes in visual acuity or refraction were documented.

CONCLUSIONS

Tacrolimus dermatologic ointment is a potentially safe and effective treatment for AKC cases refractory to standard treatment and may substitute for steroid treatments aimed at controlling disease activity.

Heparin treatment for allergic conjunctivitis in the experimental BALB/c model

PURPOSE

To compare the inhibitory effects of dexamethasone and heparin on the infiltration of mast cells in the conjunctiva by using a mouse allergic conjunctivitis model.

METHODS

24 Balb/c mice were divided into four groups: allergy group (positive control), dexamethasone group, heparin group, and negative control group, as groups 1, 2, 3, and 4, respectively. Each group comprised 6 mice, and experimental allergic conjunctivitis was developed in groups 1, 2, and 3. The mice in group 2 were treated with topical 0.1% dexamethasone eye ointment, and the mice in group 3 were treated topically with 5,000 IU/ml standard heparin. Both dexamethasone and heparin were instilled once a day for 4 days. Hanks' balanced salt solution was dropped into both eyes of the mice in group 4 instead of dexamethasone or heparin. Eyeballs and eyelids were removed from the mice in all groups while one eye of each animal was used for histopathological, the other for molecular biological examination.

RESULTS

Mast cells, infiltrating the subconjunctival tissue, were significantly lower in group 2 (p < 0.0001), group 3 (p < 0.0001) and group 4 (p < 0.0001) when compared to group 1.

CONCLUSIONS

Topical heparin could be a viable option in treating IgE-induced allergic eye disease since it is found to be as effective as topical dexamethasone in experimental acute allergic eye disease.

Topical 0.005% tacrolimus eye drop for refractory vernal keratoconjunctivitis

PURPOSE

To evaluate the efficacy and safety of topical 0.005% tacrolimus eye drop for treatment of refractory vernal keratoconjunctivitis (VKC).

METHODS

This prospective study included 20 eyes of 10 patients with refractory VKC, who had active symptomatic disease despite conventional medications including topical steroids. After discontinuing all other medications, patients were treated with topical 0.005% tacrolimus eye drop four times a day. Changes in subjective symptoms and objective signs after treatment were evaluated, and development of possible complications was assessed.

RESULTS

Mean age of patients was 21.3±7.4 years and mean duration of VKC was 12.1±5.8 years. After starting tacrolimus eye drop, patients were followed for a mean duration of 10.7±3.7 months (range, 6-15 months). All symptoms including itching, redness, photosensitivity, foreign body sensation, and mucus discharge improved after the treatment; itching was the first symptom to show dramatic relief. In addition, there was improvement in objective signs including conjunctival hyperaemia, conjunctival papillary hypertrophy, giant papillae, limbal hypertrophy, corneal punctate epithelial erosions, and corneal pannus; conjunctival hyperaemia was the first sign to show improvement. No patient required addition of other medications including steroids for further relief. Any attempt to discontinue tacrolimus eye drop was associated with recurrence of patients' symptoms and signs, necessitating continued use of the medication during the entire follow-up time. No ocular complication related to tacrolimus was noted.

CONCLUSION

Topical 0.005% tacrolimus eye drop seemed to be a safe and effective treatment for steroid-resistant refractory VKC; however, long-term use was needed to control the disease.

Use of systemic T-lymphocyte signal transduction inhibitors in the treatment of atopic keratoconjunctivitis

PURPOSE

Topical immunomodulators such as tacrolimus have revolutionized the treatment of atopic dermatitis. Because T lymphocytes are integral to the pathogenesis of atopic dermatitis, systemic treatment with T-lymphocyte signal transduction inhibitors should ameliorate both the dermatologic and ocular manifestations. We describe the successful treatment of 6 patients with severe atopic keratoconjunctivitis (AKC) resistant to conventional therapies.

METHODS

Retrospective observational case series. The charts of patients with AKC assessed by 1 of the authors were reviewed to identify those treated with systemic T-cell signal transduction inhibitors. Visual acuities, previous treatments, and the response to systemic signal transduction inhibitors were observed and reported in 6 patients.

RESULTS

The patients had a mean duration of AKC of 21 years. Topical corticosteroids and antihistamines had failed to control signs and symptoms of the disease in all patients, and in some patients, systemic corticosteroids and topical cyclosporine were ineffective. Three patients were treated with systemic cyclosporine, and 3 were treated with systemic tacrolimus. One patient was subsequently treated with daclizumab in addition to tacrolimus. All 6 patients experienced complete remission of their AKC and an increase in visual acuity.

CONCLUSIONS

Selective systemic immunosuppression of T lymphocytes with cyclosporine or tacrolimus has proved effective in the treatment of both atopic dermatitis and atopic keratoconjunctivitis. We advocate the consideration of systemic therapy in cases that are resistant to conventional treatment to resolve inflammation and preserve vision. Further studies in this area are advocated.

Systemic tacrolimus in the treatment of severe atopic keratoconjunctivitis

PURPOSE

Severe atopic keratoconjunctivitis (AKC) forms part of the spectrum of allergic eye disease and is often refractory to conventional topical treatment. Topical cyclosporin A and tacrolimus have been shown to reduce immunologic activation, symptoms, and signs of patients suffering from AKC, but there are no reports on safety and efficacy of systemic tacrolimus for this condition.

METHODS

We report on a retrospective study of 3 patients with severe AKC, where the disease did not respond to conventional therapy, and they were therefore treated with low-dose systemic tacrolimus for at least 1 year as an adjunct to their existing treatment.

RESULTS

There was a good clinical response in all patients to low-dose systemic tacrolimus, with a low incidence of side effects and no relapse of symptoms after discontinuation of treatment.

CONCLUSION

Low-dose systemic tacrolimus is a safe and effective treatment of some patients with severe AKC, which is refractory to conventional treatment. Such patients need careful monitoring for side effects, and the long-term benefits need to be assessed as part of a clinical trial.

Animal models of allergic and inflammatory conjunctivitis

Allergic eye diseases are complex inflammatory conditions of the conjunctiva with an increasing prevalence and incidence. The diseases are often concomitant with other allergic diseases such as allergic rhinitis, atopic dermatitis and allergic asthma. Despite the disabling and prominent symptoms of ocular allergies, they are less well studied and further insights into the molecular basics are still required. To establish new therapeutic approaches and assess immunological mechanisms, animal models of ocular allergies have been developed in the past years. The major forms of allergic ocular diseases, seasonal and perennial allergic conjunctivitis, vernal and atopic keratoconjunctivitis and giant papillary conjunctivitis, each have different pathophysiological and immunological components. In contrast to these distinct entities, the current animal models are based on the sensitization against a small number of allergens such as ovalbumin, ragweed pollen or major cat allergens and consecutive challenge. Different animal species have been used so far. Starting with guinea-pig models of allergic conjunctivitis to assess pharmacological aspects, new models including rats and mice have been developed which mimic major features of ocular allergy. The presently preferred species for the investigation of the immunological basis of the disease is represented by murine models of allergic conjunctivitis. In the future, combined ocular, nasal and aerosolic challenges with allergens may provide a model of allergy that encompasses simultaneously the target organs eye, nose and airways with conjunctivitis, rhinitis and asthma.