Evaluation of the effects of 15(S)-HETE on corneal epithelial cells: an electrophysiological and cytochemical study

Allergic eye disease

Ocular allergy is one of the most common conditions encountered by pediatricians and ophthalmologists and is characterized by bilateral injection with itching as the predominant symptom. Risk factors include history of atopy (asthma, eczema, seasonal allergies). Basic and clinical research have provided insight into the immunologic mechanisms, clinical presentation, differential diagnosis, and pharmacologicmanagement of this condition. New pharmacologic agents have improved the efficacy and safety of ocularallergy treatment. This article discusses the classification of ocular allergy diagnosis and management, and addresses clinical symptoms and signs that indicate more severe allergic disease or alternative diagnosis that should prompt expeditious referral to an ophthalmologist.

Allergic conjunctivitis: a comprehensive review of the literature

Ocular allergy represents one of the most common conditions encountered by allergists and ophthalmologists. Allergic conjunctivitis is often underdiagnosed and consequently undertreated. Basic and clinical research has provided a better understanding of the cells, mediators, and immunologic events, which occur in ocular allergy. New pharmacological agents have improved the efficacy and safety of ocular allergy treatment. An understanding of the immunologic mechanisms, clinical features, differential diagnosis, and treatment of ocular allergy may be useful to all specialists who deal with these patients. The purpose of this review is to systematically review literature underlining all the forms classified as ocular allergy: seasonal allergic conjunctivitis, perennial allergic conjunctivitis, vernal keratoconjunctivitis, atopic keratocongiuntivitis, contact allergy, and giant papillary conjunctivitis.

Effect of short-term diphenhydramine administration on aqueous tear production in normal dogs

OBJECTIVE

To perform a randomized, placebo-controlled, masked clinical trial using a cross-over design to determine the effect of oral diphenhydramine on aqueous tear production in normal dogs.

ANIMALS STUDIED

Seventeen dogs with normal ophthalmic examinations.

PROCEDURES

Baseline tear production was established for each dog by performing Schirmer tear test I (STT I). Dogs received 20-day treatment courses of both oral diphenhydramine and placebo solutions with a 10-day washout period between treatment periods. Each dog was randomly assigned to receive diphenhydramine or placebo at the outset of the study. Measurements of STT I values were measured at regular intervals during the study and were conducted at the same time of day throughout the study to control for diurnal variations in tear production. The significance of the impact of diphenhydramine treatment on the quantity of aqueous tear production, as determine by STT results over time, was evaluated using regression analysis with appropriate transformation.

RESULTS

Statistical comparisons at each measurement time, including baseline measurements between control and treatment groups, revealed no significant differences. Mean STT I levels also did not differ significantly at any measurement time compared to baseline for treatment or control groups.

CONCLUSIONS

Short-term administration of oral diphenhydramine does not result in a significant decrease in aqueous tear production in normal dogs.

Bepotastine besilate ophthalmic solution for the relief of nonocular symptoms provoked by conjunctival allergen challenge

BACKGROUND

Bepotastine besilate is a selective histamine1-receptor antagonist and mast cell stabilizer with inhibitory effects on eosinophilic activity.

OBJECTIVE

To evaluate the safety and efficacy of 1.5% bepotastine besilate ophthalmic solution in alleviating nonocular symptoms induced by a conjunctival allergen challenge (CAC), a clinical model of allergic conjunctivitis.

METHODS

This was a single-center, double-masked, randomized, placebo-controlled clinical trial performed from March 1 to April 4, 2007. Patients 10 years or older with a history of allergic conjunctivitis and a reproducible, positive, clinical response to a CAC were eligible. Patients received either placebo or 1.5% bepotastine besilate, 1 drop in each eye. After 15 minutes, 8 hours, or 16 hours after dosing, a CAC was performed and patients evaluated nonocular symptoms using standardized grading scales.

RESULTS

Seventy-one patients were enrolled in the study, and 66 comprised the per protocol population. A clinically meaningful reduction (> or = 1.0 unit) compared to placebo was achieved for rhinorrhea and nasal congestion at most time points after 1.5% bepotastine besilate instillation at 8 hours before a CAC test. Significant reductions (P < or = .05) in mean values were seen with 1.5% bepotastine besilate at 15 minutes and 8 hours after dosing for CAC-induced nasal congestion, rhinorrhea, ear or palate pruritus, nasal pruritus, and summed nonocular composite symptom (NOCS) scores and also at 16 hours after dosing for nasal congestion and rhinorrhea.

CONCLUSIONS

The 1.5% bepotastine besilate formulation produced statistically significant reductions after a CAC in individual nonocular symptoms and NOCS scores at onset of allergic response and for at least 8 hours after instillation, with the greatest reduction seen for nasal congestion and rhinorrhea.

Management and Therapy of Dry Eye Disease: Report of the Management and Therapy Subcommittee of the International Dry Eye WorkShop (2007)

The members of the Management and Therapy Subcommittee assessed current dry eye therapies. Each member wrote a succinct evidence-based review on an assigned aspect of the topic, and the final report was written after review by and with consensus of all subcommittee members and the entire Dry Eye WorkShop membership. In addition to its own review of the literature, the Subcommittee reviewed the Dry Eye Preferred Practice Patterns of the American Academy of Ophthalmology and the International Task Force (ITF) Delphi Panel on Dry Eye. The Subcommittee favored the approach taken by the ITF, whose recommended treatments were based on level of disease severity. the recommendations of the Subcommittee are based on a modification of the ITF severity grading scheme, and suggested treatments were chosen from a menu of therapies for which evidence of therapeutic effect had been presented.

Ocular toxicity of systemic asthma and allergy treatments

Systemic medications, such as antihistaminic and anti-inflammatory agents used in the treatment of asthma and allergy, may have adverse effects on the eye. The major adverse effects on the eye have included cataracts, glaucoma, and tear-film dysfunction (dry-eye syndrome). The use of inhaled corticosteroids (bronchial and nasal) has been associated with mild systemic effects when compared with oral corticosteroids. The development of cataracts and glaucoma has been more commonly associated with earlier "hard" oral and inhaled steroids that affected individuals with an inherent high susceptibility or those who used them for several years. Whereas oral antihistamines commonly have an effect on allergies within hours, they also may exacerbate dry-eye complaints that commonly complicate symptoms with various forms of tear film dysfunction or conjunctival hyperreactivity. Clinicians should be aware that other systemic agents may complicate their attempts to maximize the treatment of ocular allergies.

Mast cell stabilization and anti-histamine effects of olopatadine ophthalmic solution: a review of pre-clinical and clinical research

BACKGROUND

Histamine receptor activation and degranulation of mast cells are the mechanisms by which the ocular itching, hyperemia, chemosis, eyelid swelling, and tearing of seasonal allergic conjunctivitis are induced. Some of the topical solutions available as anti-allergy therapies are intended to interfere with these mechanisms, and the body of research regarding the capabilities of these therapeutic molecules continues to expand.

OBJECTIVE

To review the currently available literature regarding one topical ophthalmic anti-allergy agent, olopatadine (Patanol), and its anti-histaminic and mast cell stabilizing actions, both in pre-clinical and clinical settings.

DESIGN AND METHODS

Relevant research of laboratory, animal model, and clinical trial studies performed using olopatadine was reviewed. MEDLINE literature searches were conducted and supplemented by additional reports which furthered relevant discussion or were necessary to verify the information resulting from original searches.

RESULTS

Olopatadine demonstrates unique properties both pre-clinically and clinically which differentiate it from other therapeutic molecules in its class of dual action mast cell stabilizer/anti-histamine. Its non-perturbation of cell membranes, human conjunctival mast cell stabilization in vivo and in vitro, and superior efficacy as compared to other topical anti-allergic medications including mast cell stabilizers, anti-histamines, and dual action agents, all contribute to olopatadine's profile.

CONCLUSIONS

Peer-reviewed literature suggests that olopatadine is clinically superior to the other anti-allergic molecules because of its strong anti-histaminic qualities and its unique ocular mast cell stabilizing properties.

Short-chain fatty acids alter tight junction permeability in intestinal monolayer cells via lipoxygenase activation

OBJECTIVE

Involvement of lipoxygenase (LOX) and cyclo-oxygenase (COX) on cellular differentiation or apoptosis induced by butyrate has been reported recently, but the effect on tight junction (TJ) permeability has not been reported. One major activity of butyrate and, to a lesser extent, propionate is to modulate gene transcription via histone acetylation by their histone deacetylase inhibitor activity. In this study, we evaluated the activation of LOX and COX in TJ permeability changes by short-chain fatty acids, butyrate, propionate, and acetate in intestinal monolayer cells and their possible mechanism by histone acetylation.

METHODS

The effects of LOX and COX inhibitors on TJ permeability and the expression of LOX or COX mRNA induced by short-chain fatty acids were investigated in Caco-2 cells using Transwell chambers. The effects of hydroxyeicosatetraenoic acid (a product of LOX) on TJ permeability were also evaluated. The effects of short-chain fatty acids were compared with those of trichostatin A (histone deacetylase inhibitor).

RESULTS

A LOX inhibitor clearly inhibited the effect of butyrate on TJ permeability, whereas COX inhibitors did not. The LOX and COX inhibitors partly inhibited the effects of propionate but not of acetate. Butyrate increased LOX mRNA expression, and hydroxyeicosatetraenoic acid and trichostatin A mimicked its effect.

CONCLUSION

These results suggest that short-chain fatty acids, especially butyrate, induce TJ permeability changes through LOX activation through histone acetylation.