Advances in pharmacotherapy for allergic conjunctivitis

Trans-eyelid distribution of epinastine to the conjunctiva following eyelid application in rabbits

PURPOSE

To reveal the penetration of epinastine, an anti-allergic ophthalmic agent, into the eyelid and its distribution to the conjunctiva after administration of a cream formulation on rabbit eyelid skin.

STUDY DESIGN

Experimental study.

METHODS

Rabbits were treated with 0.5% epinastine cream on hair-shaved eyelids, followed by preparation of eyelid tissue slices to determine spatial tissue distribution of epinastine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantification using laser-microdissected tissues and desorption electrospray ionization mass spectrometry imaging (DESI-MSI). In addition, following either eyelid application of 0.5% epinastine cream or ocular instillation of 0.1% epinastine eye drops, concentration-time profiles of epinastine in the palpebral conjunctiva and bulbar conjunctiva were determined using LC-MS/MS.

RESULTS

Laser microdissection coupled with LC-MS/MS analysis detected high concentrations of epinastine around the outermost layer of the eyelid at 0.5 h post-administration that gradually diffused deeper into the eyelid and was distributed in the conjunctival layer at 8 and 24 h post-administration. Similar time-dependent drug distribution was observed in high-spatial-resolution images obtained using DESI-MSI. Epinastine concentrations in the conjunctival tissues peaked at 4-8 h after administration of 0.5% epinastine cream and then decreased slowly over 72 h post-administration. In contrast, epinastine concentrations peaked quickly and decreased sharply after epinastine eye drop administration.

CONCLUSION

After the application of epinastine cream to the eyelid skin, epinastine gradually permeated the eyelid. The compound was retained in the conjunctiva for 8-24 h post-administration, indicating that epinastine cream is a promising long-acting formulation for treating allergic conjunctivitis.

Allergic Conjunctivitis: Review of Current Types, Treatments, and Trends

Allergic conjunctivitis is an allergen-induced immune response secondary to the binding of immunoglobulin-E (IgE) to sensitized mast cells. Approximately 40% of North Americans and 20% of the world's population are impacted by some form of allergy and it continues to increase in prevalence, especially among children. Specified IgE antibodies can be found in almost all cases of exposure to seasonal or perennial allergens. Activation and degranulation of mast cells lead to increased tear levels of histamine, tryptase, leukotrienes, cytokines, and prostaglandins. The release of these factors initiates the recruitment of inflammatory cells in the conjunctival mucosa, which causes the late-phase reaction. Signs and symptoms of ocular allergies include itching, tearing, chemosis, and hyperemia, which can lead to decreased productivity and poor quality of life. Many treatment options are available to improve symptoms, including, mast cell stabilizers, antihistamines, dual-acting agents, steroids, nonsteroidal anti-inflammatory drugs (NSAIDS), and other off-label treatment modalities. This review article provides an overview of different types of allergic conjunctivitis, its pathology and immunology, and recommended methods of treatment.

Epinastine Cream: A Novel Once-Daily Therapeutic Agent for Allergic Conjunctivitis

Purpose: To investigate the in vivo efficacy of epinastine cream in type I allergic models. Methods: The dose, timing, and antiallergic effect of epinastine cream on the conjunctiva were evaluated postapplication to the eyelid skin of guinea pigs with histamine- or ovalbumin-induced allergic conjunctivitis. Additionally, we assessed its antiallergic effects on the skin postapplication to the dorsal skin of guinea pigs with ovalbumin-induced passive cutaneous anaphylaxis. Efficacy was estimated by determining the amount of dye that leaked from conjunctival or dorsal skin tissue vessels as a measure of vascular permeability, scoring the severity of allergic symptoms, and observing the scratching behaviors using clinical parameters. Results: In the histamine-induced conjunctivitis model, epinastine cream strongly inhibited conjunctival vascular permeability in a dose-dependent manner. The inhibitory effect of 0.5% epinastine cream 24 h postapplication was significantly higher than that of 0.1% epinastine hydrochloride ophthalmic solution 8 h postadministration. Additionally, the 0.5% epinastine cream inhibited conjunctival vascular permeability 15 min postapplication, and the effect was sustained over 24 h. Furthermore, the 0.5% epinastine cream effectively suppressed clinical symptom scores and exhibited ameliorated scratching bouts in conjunctival allergic reactions in the experimental allergic conjunctivitis model. Additionally, it significantly inhibited vascular permeability in skin allergic reactions in the passive cutaneous anaphylaxis model. Conclusions: The results suggest that epinastine cream is a strong, long-lasting, and skin-penetrating inhibitor of type I allergic reactions. The 0.5% epinastine cream applied once daily could be a promising, potent, and long-acting therapeutic agent for allergic conjunctivitis.

Dermatophagoides Pteronyssinus 1 (DerP1) May Trigger NLRP3-Mediated Corneal Epithelial Cell Pyroptosis by Elevating Interleukin-33 Expression Levels

PURPOSE

To characterize the in vivo effects of Dermatophagoides pteronyssinus 1 (DerP1) in mice and determine the underlying NLRP3 inflammasome-mediated pyroptosis signaling mechanisms in the human corneal epithelial cells (HCECs).

METHODS

DerP1 was used to induce allergic conjunctivitis in C57 mice. HCECs were sensitized with DerP1 in vitro to mimic their condition observed in allergic conjunctivitis in vivo. Transmission electron microscopy was used to evaluate pyroptosis in the HCECs, enzyme-linked immunosorbent assays to assess interleukin (IL)-33, IL-1β and IL-4 levels, flow cytometry to detect the proportion of Th2 cells, MTT assays to assess cell metabolic activity, immunofluorescence to evaluate the effects of DerP1 on functional HCEC phenotypes, and Western blot assays to detect the expression of NOD-like receptor family pyrin domain-containing 3 (NLRP3), gasdermin D (GSDMD), N-terminal fragment of GSDMD (GSDMD-N), pro-caspase-1, cleaved caspase-1, IL-1β, and IL-33. IL-33 expression in the HCECs was knocked down via lentivirus transfection.

RESULTS

In vivo, DerP1 promotes pyroptosis, production of Th2 inflammatory cytokines and IL-33, and NLRP3 activation in mouse corneas. In vitro, pyroptotic bodies were found in the HCECs after sensitization with DerP1. Various concentrations of DerP1 increased the expression levels of NLRP3, GSDMD, GSDMD-N, pro-caspase-1, cleaved caspase-1, and IL-1β in the HCECs, with the largest increase observed after exposure to 20 µM DerP1. In vitro, recombinant human IL-33 mediated the expression of pyroptotic biomarkers in the HCECs, whereas IL-33 silencing diminished 20 µM DerP1-induced increase in their expression levels.

CONCLUSIONS

DerP1 induces pyroptosis and allergic conjunctivitis, the expression of Th2 inflammatory cytokines, NLRP3 activation, and IL-33 in mouse corneas in our model. These effects would attribute to its activating NLRP3-GSDMD signaling pathway axis via enhancing IL-33 expression in HCECs.

The Protective Effects of KAT5 Inhibition on Ocular Inflammation by Mediating the PI3K/AKT Pathway in a Murine Model of Allergic Conjunctivitis

Purpose

We aimed to explore the effect of lysine acetyltransferase KAT5 on allergic conjunctivitis (AC).

Methods

The effect of KAT5 on inflammatory response during AC progression was analyzed in the experimental allergic conjunctivitis (EAC) mouse model.

Results

The clinical score, permeability, total IgE, ovalbumin (OVA)-specific IgE, and IgG1/IgG2a were induced in the EAC mice, in which the overexpression of KAT5 could further enhance but KAT5 inhibitor NU9056 reduce the phenotypes. The eosinophilic infiltration was induced in EAC mice, in which the overexpression of KAT5 was able to further promote but NU9056 attenuate the phenotype. The expression of Eotaxin and RANTES and the inflammatory factors were upregulated in EAC mice and KAT5 overexpression increased, but NU9056 decreased the expression in the model. Significantly, the CD11c+ dendritic cells and CD4+ T cells infiltration in the conjunctiva was enhanced in EAC mice, whereas KAT5 overexpression induced but NU9056 suppressed the effect in the model. Mechanically, the phosphorylation of PI3K and Akt and the levels of histone H3 lysine 27 acetylation (H3K27ac) were enhanced in EAC mice, whereas the overexpression of KAT5 promoted and NU9056 repressed the phenotype in the mice. The enrichment of KAT5 and H3K27ac on PI3K promoter was increased in EAC mice, and the overexpression of KAT5 further enhanced the enrichment in the mice. Significantly, we observed similar results in the KAT5 knockout mice as well. Moreover, PI3K/AKT signaling inhibitor LY294002 reversed KAT5 overexpression-mediated phenotypes and inflammatory response after induction AC in vivo.

Conclusions

Therefore we concluded that KAT5 inhibition protected against ocular inflammation by mediating the PI3K/AKT pathway in EAC mouse model.

Efficacy of N-acetyl aspartyl glutamic acid versus fluorometholone for treating allergic conjunctivitis in an environmental exposure chamber

Background

Topical mast cell stabilizers were previously shown to treat the signs and symptoms of seasonal and perennial allergic conjunctivitis safely and effectively in active and placebo‐controlled trials. However, mast cell stabilizers have not been compared to topical corticosteroids for efficacy. We tested the non‐inferiority of a topical mast cell stabilizer, N‐acetyl aspartyl glutamic acid (4.9%, NAAGA), compared to fluorometholone (0.1%, FM) during controlled exposures to the airborne birch pollen allergen, Bet v 1, in an environmental exposure chamber (EEC).

Methods

This randomized, cross‐over, investigator‐blinded study included 24 patients with a history of birch pollen allergic conjunctivitis. Patients were randomized to 5 days of treatment with NAAGA, then FM (n = 12) or FM, then NAAGA (n = 12). After each treatment, patients were exposed to a fixed airborne concentration of Bet v 1 in ALYATEC EEC. The primary endpoint was the amount of allergen required to trigger a conjunctival response (Abelson score ≥5). Groups were compared with a linear model for cross‐over studies. Non‐inferiority was assumed, when the lower bound of the risk ratio confidence interval (CI) was >0.5.

Results

At screening, the mean time‐to‐conjunctival response was 72.5 ± 35.9 min. NAAGA and FM extended the response time to 114.8 ± 55.0 and 116.6 ± 51.5 min respectively. The mean amounts of allergen required to trigger a conjunctival response were 1.165 ng after NAAGA and 1.193 ng after FM treatment. The risk ratio for the conjunctival response was 0.977 (95% CI: 0.812; 1.174), which indicated non‐inferiority. Adverse events occurred less frequently with NAAGA (29.2%) than with FM (58.3%).

Conclusion

In patients with allergic conjunctivitis to birch pollen, NAAGA was non‐inferior to FM in exposures to airborne Bet v 1. The EEC was a good model for simulating real‐life airborne allergen exposure and for demonstrating the efficacy and safety of eye drops for treating allergic conjunctivitis.

Trial registration

Not registered.

Characterization of Conjunctival Sac Microbiome from Patients with Allergic Conjunctivitis

Conjunctival sac microbiome alterations have been reported to be closely associated with many ocular diseases. However, the characteristic of conjunctival sac microbiome in allergic conjunctivitis (AC) was scarcely described. In this study, we aimed to identify the differences of the conjunctival sac microbiome composition in AC patients compared with normal controls (NCs) using high-throughput 16S rDNA sequencing metagenomic analysis. The conjunctival sac microbiome samples from 28 AC patients and 39 NC patients were collected. The V3-V4 region of 16S rRNA gene high-throughput sequencing was performed on the illumina MiSeq platform. Alpha diversity, beta diversity and the relative abundance at the phylum and genus levels were analyzed using QIIME. Alpha diversity demonstrated by Chao1, Observed_species and PD_whole_tree indexes did not show significant difference between the AC and NC groups, while the Shannon index was higher in the AC group. Beta diversity showed divergent microbiome composition in different groups (p < 0.005). The top five abundant phyla were Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota and Cyanobacteria in both groups. The top five abundant genera were Bacillus, Staphylococcus, Corynebacterium, Acinetobacter and Ralstonia in the AC group and Acinetobacter, Staphylococcus, Bacillus, Clostridium_sensu_stricto_1, Corynebacterium and Geobacillus in the NC group. The Firmicutes/Bacteroidetes (F/B) ratio at the phylum level was similar between groups (p = 0.144). The Bacillus/Acinetobacter (B/A) ratio at the genus level was higher in the AC group (p = 0.021). The dysbiosis detected in this study might provide further evidence to investigate the mechanism and treatment methods for allergic conjunctivitis.

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.

To evaluate the efficacy and safety of olopatadine 0.1% ophthalmic solution and bepotastine 1.5% ophthalmic solution in patients with vernal keratoconjunctivitis in a tertiary care hospital

INTRODUCTION

Vernal conjunctivitis comprises 0.5% of allergic eye diseases. The study is intended to collate the effectiveness of drugs by observing the reduction in signs and symptoms.

OBJECTIVES

The objective of the study is to evaluate the effectiveness and safety of olopatadine 0.1% ophthalmic drops with bepotastine besilate 1.5% ophthalmic drops in patients with vernal keratoconjunctivitis (VKC).

MATERIALS AND METHODS

A randomized, open-label, comparative study conducted in Sarojini Devi Eye Hospital, Telangana. The study included 50 patients diagnosed with VKC, of which Group A and Group B were given olopatadine 0.1% ophthalmic drops and bepotastine besilate 1.5% ophthalmic drops, respectively, twice a day for 8 weeks. The reduction in signs and symptoms in both groups was compared. The observations and results were tabulated accordingly, and data were analyzed using the SPSS. The unpaired t-test is used as the test of significance in between two groups. P value is statistically significant when it is less than 0.05.

RESULTS

Overall, 50 cases were included in the study, 72% of total patients were in the age group of 5-10 years, and 28% were in the age group of 11-15 years. There were 39 males and 11 females. After 8 weeks of follow-up, the mean reduction in the scoring of symptoms and signs provided better and quicker relief of watering, ocular discomfort, and conjunctival hyperemia with bepotastine 1.5% eye drops. Olopatadine 0.1% eye drops provided faster improvement in papillary hypertrophy. Both drugs were equally effective in reducing itching. Laboratory findings of absolute eosinophil count had no statistical significance in between the two groups.

CONCLUSIONS

In this study, based on the evaluation of therapeutic performance, bepotastine eye drops proved quicker relief of symptoms and signs compared to olopatadine eye drops but was not statistically significant which would prove beneficial for the patients.

Discovery to Launch of Anti-allergy (Emadine; Patanol/Pataday/Pazeo) and Anti-glaucoma (Travatan; Simbrinza) Ocular Drugs, and Generation of Novel Pharmacological Tools Such as AL-8810

The eye and eyesight are exquistly designed and are precious, and yet we often take them for granted. Good vision is critical for our long-term survival and for humanity's enduring progress. Unfortunately, since ocular diseases do not culminate in life-and-death scenarios, awareness of the plight of millions of people suffering from such eye ailments is not publicized as other diseases. However, losing eyesight or falling victim to visual impairment is a frightening outlook for most people. Glaucoma, a collection of chronic optic neuropathies, of which the most prevalent form, primary open-angle glaucoma (POAG), is the second leading cause of irreversible blindness. POAG currently afflicts >70 million people worldwide and is an insidious, progressive, silent thief of sight that is asymptomatic. On the other hand, allergic conjunctivitis (AC), and the associated rhinitis ("hay-fever"), frequently victimizes a huge number of people worldwide, especially during seasonal changes. While not life-threatening, sufferers of AC soon learn the value of drugs to treat their signs and symptoms of AC as they desire rapid relief to overcome the ocular itching/pain, redness, and tearing AC causes. Herein, I will describe the collective efforts of many researchers whose industrious, diligent, and dedicated team work resulted in the discovery, biochemical/pharmacological characterization, development and eventual launch of drugs to treat AC (e.g., olopatadine [Patanol/Pataday/Pazeo] and emedastine [Emedine]), and for treating ocular hypertension and POAG (e.g., travoprost [Travatan ] and Simbrinza). This represents a personal perspective.

The Role of Th17 Cells and IL-17 in Th2 Immune Responses of Allergic Conjunctivitis

Allergic conjunctivitis (AC) is a common allergic disease that is often associated with the onset of rhinitis or asthma. The incidence of AC has increased significantly in recent years possibly due to air pollution and climate warming. AC seriously affects patients' quality of life and work efficiency. Th (T-helper) 2 immune responses and type I hypersensitivity reactions are generally considered the basis of occurrence of AC. It has been found that new subpopulations of T-helper cells, Th17 cells that produce interleukin-17 (IL-17), play an important role in the Th2-mediated pathogenesis of conjunctivitis. Studies have shown that Th17 cells are involved in a variety of immune inflammation, including psoriasis, rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, and asthma. However, the role of Th17 and IL-17 in AC is unclear. This paper will focus on how T-helper 17 cells and interleukin-17 are activated in the Th2 immune response of allergic conjunctivitis and how they promote the Th2 immune response of AC.

The effectiveness of olopatadine hydrochloride eye drops for allergic conjunctivitis: Protocol for a systematic review

BACKGROUND

Allergic conjunctivitis (AC) is a multifactorial and common type of ocular surface disease that affects many people. The quality of life for AC patients can be significantly decreased caused by symptoms of ocular itching, swelling, redness, and tearing. Topical antihistaminics, mast cell stabilizers, non-steroidal anti-inflammatory drugs (NSAIDs), and steroids have been widely used to treat AC. Many clinical trials have indicated that olopatadine hydrochloride eye drops can provide quick relief of symptoms and signs. The purpose of this review is to evaluate systematically the effectiveness of olopatadine hydrochloride eye drops for treating AC.

METHODS

A systematic review of all of the randomized controlled trials on the effectiveness and safety of olopatadine hydrochloride eye drops for AC will be conducted. We will search PubMed, Web of Science (WOS), EMBASE (OVID), the Cochrane Library, Google Scholar, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal database (VIP), Wanfang Database, and CBM, from the database inception date to October 31, 2019. There are no language or publication status restrictions. Registers of clinical trials, potential gray literature, reference lists of studies, and conference abstracts will also be searched. Two reviewers will independently read the articles, extract the data information, and assess the quality of the studies. Data will be synthesized by a heterogeneity test. The primary outcomes include the main symptom and sign scores before and after treatment, the eye redness index, the presence of eosinophils in the conjunctival scraping. Quality of life, the total treatment efficacy, and safety will be evaluated as the secondary outcomes. RevMan V.5.3 software will be used for the meta-analysis.

RESULTS

The study will provide an objective and normative systematic review to evaluate the effectiveness and safety of olopatadine hydrochloride eye drops for the treatment of AC.

CONCLUSION

Our review will provide useful information to judge whether olopatadine hydrochloride eye drops is an effective intervention for patients with AC.

ETHICS AND DISSEMINATION

It is not necessary to obtain ethical approval as participants are not involved patients. The protocol and results will be published in a peer-reviewed journal. The systematic review will also be disseminated electronically and in print to help guide health care practice and policy.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019132232.

Phase III trials examining the efficacy of cetirizine ophthalmic solution 0.24% compared to vehicle for the treatment of allergic conjunctivitis in the conjunctival allergen challenge model

Purpose

The purpose of these Phase III studies was to evaluate the efficacy and safety of cetirizine ophthalmic solution 0.24% compared with vehicle in the treatment of allergen-induced conjunctivitis using the Ora conjunctival allergen challenge (CAC)^® model.

Methods

The single-center (Study 1) and multi-center (Study 2), double-masked, randomized, vehicle-controlled, parallel group, CAC studies were conducted over ~5 weeks and four study visits. The study design only differed in entry criteria: Study 2 required more severe allergic conjunctivitis symptoms. Subjects were screened for an allergen response at Visits 1 and 2 and then randomized at Visit 3. Approximately 100 subjects were randomized in each study. The primary efficacy endpoints were ocular itching and conjunctival redness 15 minutes and 8 hours post-treatment, post-CAC.

Results

Cetirizine treatment administered 15 minutes or 8 hours prior to CAC resulted in significantly lower ocular itching at all time points post-CAC (P<0.0001) compared to vehicle in both studies. Conjunctival redness measured by the investigator was significantly lower after cetirizine treatment compared to vehicle at 7 minutes post-CAC at both 15 minutes and 8 hours post-treatment in both studies (P<0.05). All secondary endpoints were in favor and confirmatory of cetirizine efficacy with significant improvement in chemosis, eyelid swelling, tearing, ciliary redness, and episcleral redness, as well as nasal symptoms (rhinorrhea, nasal pruritus, ear or palatal pruritus, and nasal congestion) post-CAC. The most robust treatment differences were observed in Study 2 where more severe symptoms were required for study entry (P<0.05). No safety concerns for cetirizine ophthalmic solution 0.24% were identified.

Conclusion

Cetirizine ophthalmic solution 0.24% was shown to be efficacious in the treatment of ocular and nasal signs and symptoms associated with allergic conjunctivitis and demonstrated a favorable safety profile. Clinical efficacy was demonstrated with a 15-minute onset of action and añ8-hour duration of action.

α4β7 integrin inhibitors: a patent review

INTRODUCTION

The α₄β₇ integrin is heterodimeric cell surface receptors expressed on most leukocytes. Mucosal addressing cell adhesion molecule 1(MAdCAM-1) is an exclusive ligand for α₄β₇ integrin. Areas covered: This article will highlight the progress that has been made in the discovery and development of α₄β₇ integrin inhibitors, and their use in the treatment of inflammatory bowel diseases, multiple sclerosis, asthma, hepatic disorders, human immunodeficiency virus, allergic conjunctivitis and type 1 diabetes. Expert opinion: α₄β₇ integrin inhibitors have attracted much interest for their clinical implication. Natalizumab and Vedolizumab are monoclonal antibodies (mAbs) successfully utilized clinically. Natalizumab is a mAbs of α₄-subunit blocking both α₄β₁ and α₄β₇ integrin. Vedolizumab selectively targets the α₄β₇ integrin. Several mAbs are still in the process of research and development. Among these mAbs, etrolizumab selectively against the β₇-subunit and AMG-181 specifically against the α₄β₇ integrin are the most promising anti-α₄β₇ integrin antibodies. Despite the unclear development stage of TR-14035 and R411, several low molecular compounds show bright future of further development, such as AJM300 and CDP323. In addition, results from laboratory data show that peptide inhibitors, such as peptide X, are effective α₄β₇ integrin inhibitors.

DS-70, a novel and potent α4 integrin antagonist, is an effective treatment for experimental allergic conjunctivitis in guinea pigs

BACKGROUND AND PURPOSE

Allergic conjunctivitis is an eye inflammation that involves the infiltration of immune cells into the conjunctiva via cell surface-adhesion receptors, such as integrin α₄ β₁ . These receptors interact with adhesion molecules expressed on the conjunctival endothelium and may be a target to treat this disease. We synthesized DS-70, a novel α/β-peptidomimetic α₄ integrin antagonist, to prevent the conjunctival infiltration of immune cells and clinical symptoms in a model of allergic conjunctivitis.

EXPERIMENTAL APPROACH

In vitro, DS-70 was pharmacologically characterized using a scintillation proximity procedure to measure its affinity for α₄ β₁ integrin, and its effect on cell adhesion mediated by different integrins was also evaluated. The effects of DS-70 on vascular cell adhesion molecule-1 (VCAM-1)-mediated degranulation of a human mast cell line and an eosinophilic cell line, which both express α₄ β₁ , and on VCAM-1-mediated phosphorylation of ERK 1/2 in Jurkat E6.1 cells were investigated. Effects of DS-70 administered in the conjunctival fornix of ovalbumin-sensitized guinea pigs were evaluated.

KEY RESULTS

DS-70 bound to integrin α₄ β₁ with nanomolar affinity, prevented the adhesion of α₄ integrin-expressing cells, antagonized VCAM-1-mediated degranulation of mast cells and eosinophils and ERK 1/2 phosphorylation. Only 20% was degraded after an 8 h incubation with serum. DS-70 dose-dependently reduced the clinical symptoms of allergic conjunctivitis, conjunctival α₄ integrin expression and conjunctival levels of chemokines and cytokines in ovalbumin-sensitized guinea pigs.

CONCLUSIONS AND IMPLICATIONS

These findings highlight the role of α₄ integrin in allergic conjunctivitis and suggest that DS-70 is a potential treatment for this condition.

Sublingual immunotherapy for pediatric allergic conjunctivitis: a meta-analysis of randomized controlled trials

BACKGROUND

Allergic conjunctivitis (AC) is a common chronic condition, especially in children. Ocular symptoms are often overlooked during treatment of allergic rhinoconjunctivitis (ARC). Pediatric ARC can be effectively treated using sublingual immunotherapy (SLIT), which is a guideline-recommended safe treatment approach. However, the therapeutic efficacy of SLIT in terms of ameliorating eye symptoms has not been effectively evaluated.

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) evaluating the use of SLIT for infants, children, and adolescents (aged from 3 to 18 years) with AC or ARC. We searched the Cochrane Library database, EMBASE, and Medline from November 1990 to 2017 to find papers dealing with the effects of SLIT on pediatric AC or ARC. We used standardized mean differences (SMDs) to assess therapeutic effects, employing a random effects model. Subgroup and sensitivity analyses were also conducted. The I² metric was used to evaluate heterogeneity.

RESULTS

In total, 13 clinical RCTs were included in our meta-analysis. SLIT reduced ocular symptoms to a level below that of controls (SMD = -0.21; 95% confidence interval [CI], -0.41 to -0.01; p = 0.04; I² = 55%). Notably, on subgroup analysis, SLIT clearly reduced pollen-induced pediatric AC (SMD = -0.36; 95% CI, -0.53 to -0.19; p < 0.0001; I² = 25%) but not mite-induced AC (SMD = 0.20; 95% CI, -0.20 to 0.60; p = 0.34; I² = 46%).

CONCLUSION

SLIT relieved ocular symptoms in children with ARC or AC. To confirm these results, future meta-analyses should evaluate high-quality, large-scale population-based trials.

Clinical implications of mast cell involvement in allergic conjunctivitis

The conjunctiva is a common site for the allergic inflammatory response due to it being highly vascularized, having constant exposure to environmental pollutants and allergenic pollens and having a unique conjunctival associated lymphoid tissue. The primary morbidity of anterior surface conjunctival disorders that include allergic conjunctivitis and tear film disorders is associated with its high frequency of involvement rather than its severity, although the more chronic forms can involve the cornea and lead to sight-threatening conditions. Ocular allergy is associated with IgE-mediated mast cell activation in conjunctival tissue leading to the release of preformed mediators including histamine and proteases and subsequent de novo formation of lipid-derived mediators and cytokines that trigger a cascade of cellular and molecular events leading to extensive migration and infiltration of inflammatory cells to the ocular surface. The trafficking of neutrophils, eosinophils, and lymphocytes to the ocular surface is due to establishing various chemokine gradients (mainly CCL11, CCL24, CCL5, MCP-3, and MCP-4), cell surface expression of adhesion molecules (such as VCAM-1 the ligand for VLA-4), and leukocyte adhesion to vascular endothelium. The release of preformed mediators underlies the acute ocular surface response while the secondary influx of inflammatory cells leading to the recruitment and activation of eosinophils and the subsequent activation of Th2 and Th1 lymphocytes at the level of the conjunctiva reflects the late-phase reaction.

Skullcapflavone II attenuates ovalbumin-induced allergic rhinitis through the blocking of Th2 cytokine production and mast cell histamine release

Allergic rhinitis is a common heterogeneous chronic upper airway disorder and is an IgE-mediated inflammation characterized by one or more nasal symptoms such as sneezing, itching, nasal discharge, rhinorrhea, post nasal drainage and nasal blockage. In the present study, the effects of skullcapflavone II (SCFII) on upper airway inflammation, Th2 cytokines, and NF-κB signaling in an ovalbumin (OVA)-induced allergic rhinitis (AR) murine model in vivo were investigated. OVA-induced AR mice increased nasal symptoms, eosinophils and mast cells infiltration into nasal cavity, OVA-specific IgE/IgG1 and histamine in serum, Th2 cytokines including IL-13 and GATA3, and NF-κB signaling in NALF and lung homogenate. Interestingly, treatment of SCFII reduced the levels of OVA-specific IgE/IgG1 and histamine in serum, of Th2 cytokines and of NF-κB signaling in the NALF and the lung homogenate, and histopathological changes in the nasal tissue and the lung. Also, dexamethasone suppressed such increases. The results of this study suggested that SCFII may ameliorate allergic inflammation of upper airway in AR mice model by blocking the Th2 cytokine production, the NF-κB signal pathway and the mast cell histamine release. Taken together, we suggest that SCFII may be used as a therapeutic agent for patients with Th2-mediated or mast cell-mediated allergic diseases.

Allergic diseases in the elderly: biological characteristics and main immunological and non-immunological mechanisms

Life expectancy and the number of elderly people are progressively increasing around the world. Together with other pathologies, allergic diseases also show an increasing incidence in geriatric age. This is partly due to the growing emphasis on a more accurate and careful diagnosis of the molecular mechanisms that do not allow to ignore the real pathogenesis of many symptoms until now unknown, and partly to the fact that the allergic people from 20 years ago represent the elderly population now. Moreover, environmental pollution predisposes to the onset of allergic asthma and dermatitis which are the result of internal pathologies more than the expression of allergic manifestations. At the same time the food contamination permits the onset of allergic diseases related to food allergy. In this review we provide the state of the art on the physiological changes in the elderly responsible for allergic diseases, their biological characteristics and the major immunological and extra immunological mechanisms. Much emphasis is given to the management of several diseases in the elderly, including anaphylactic reactions. Moreover, some new features are discussed, such as management of asthma with the support of physical activity and the use of the AIT as prevention of respiratory diseases and for the purpose of a real and long lasting benefit. The mechanisms of adverse reactions to drugs are also discussed, due to their frequency in this age, especially in polytherapy regimens. Study of the modifications of the immune system is also of great importance, as regards to the distribution of the lymphocytes and also the presence of a chronic inflammatory disease related to the production of cytokines, especially in prevision of all the possible therapies to be adopted to allow an active and healthy aging.

Topical Olopatadine in the Treatment of Allergic Conjunctivitis: A Systematic Review and Meta-analysis

PURPOSE

To assess the safety and efficacy of topical olopatadine versus placebo and other topical anti-allergic medications in treating allergic conjunctivitis.

METHODS

We systematically searched the literature for randomized-controlled trials that included patients with allergic conjunctivitis, compared olopatadine versus placebo or alternative anti-allergic medications, and examined itch, conjunctival hyperemia, composite symptom or sign scores, and/or occurrence of adverse events. We assessed the safety and efficacy of topical olopatadine when compared with placebo or alternative anti-allergic medications using meta-analysis.

RESULTS

When compared with placebo, topical olopatadine is associated with a pooled-mean difference (MD) in ocular itch of -1.33 (p < 0.00001) and ocular hyperemia of -0.92 (p < 0.00001). When compared with other agents, olopatadine was inferior to alcaftadine on ocular itch (pooled-MD = 0.39; p < 0.00001) but comparable with epinastine and ketotifen.

CONCLUSIONS

Topical olopatadine is a safe and effective treatment modality for allergic conjunctivitis, whereas alcaftadine appears to be superior to olopatadine in reducing ocular itch.

Update and clinical utility of alcaftadine ophthalmic solution 0.25% in the treatment of allergic conjunctivitis

Allergic disorders of the ocular surface are primarily characterized as IgE- and/or T-lymphocyte-mediated disorders that affect the cornea, conjunctiva, and eyelid. Approximately 40% of individuals in the developed countries have allergic conjunctivitis, and as such, it is the most common form of ocular allergy. Seasonal allergic conjunctivitis is the most prevalent type of allergic conjunctivitis that impacts the quality of life of patients. This article reviews the pharmacology, pharmacodynamics, pharmacokinetics, clinical trials, clinical efficacy, and safety of alcaftadine. Histamine and the pathological mechanism of ocular allergy will be briefly reviewed with the intent of providing a background for the detailed discussion on the clinical utility of alcaftadine in allergic conjunctivitis. The Medline PubMed, Elsevier Science Direct, and Google Scholar databases were used to search for evidence-based literature on histamine and immunopathological mechanism of allergic conjunctivitis, as well as on pharmacology, pharmacodynamics, pharmacokinetics, clinical trials, and clinical efficacy of alcaftadine. The treatment and management goals of allergic conjunctivitis are to prevent or minimize the inflammatory cascade associated with allergic response in the early stages of the pathological mechanism. It is of note that activation of histamine receptors on immune and nonimmune cells are associated with allergen-induced inflammation of the conjunctiva and its associated ocular allergic manifestations, including itching, edema, hyperemia, and tearing. Alcaftadine is an efficacious multiple action antiallergic therapeutic agent with inverse agonist activity on H1, H2, and H4 receptors, as well as anti-inflammatory and mast cell stabilizing effects that could provide therapeutic benefits to patients with allergic conjunctivitis.