Increased expression of Filaggrin and Claudin‐1 in the ocular surface of patients with atopic dermatitis

Abstract

Background Atopic dermatitis (AD) is an itchy, chronic and inflammatory skin condition, with dysfunctional immune response and skin barrier defects. Reduction of filaggrin (FLG) and tight junctions (TJ) proteins, such as claudin-1 (CLDN-1), expression in cutaneous epithelial barrier is remarkable in AD pathogenesis. Ocular involvement occurs in approximately 40% of AD patients leading to changes in the structure of the conjunctiva.Objectives We aimed to evaluate the expression of FLG and CLDN-1 in the ocular surface of adults with AD, analysing bulbar conjunctival cells collected by a novel non-invasive cellular imprint.Methods Bulbar conjunctival epithelial cells were collected by cellular imprint technique, and FLG and CLDN-1 expression were assessed by immunofluorescence (IF) and real-time polymerase chain reaction (RT-PCR). ResultsWe detected increased expression of FLG and CLDN-1, as well as their transcript levels in AD patients compared with healthy controls (HC). There was a positive correlation between tear film break-up time (TBUT) and FLG expression. Fluorescein staining was inversely associated with FLG expression. Conclusions Our results may reflect a reactive response of the ocular surface to AD-related ocular inflammation and associated dry eye disease. Further investigations focusing on the role of FLG and TJ expression in the ocular surface of AD patients may increment the understanding of the pathophysiology of extracutaneous AD and developing future targeted therapies.

Association of atopic dermatitis with conjunctivitis and other ocular surface diseases: A bidirectional two‐sample Mendelian randomization study

“…27 A study revealed that patients with AD had lower tear film breakup time (TBUT) values and impaired conjunctival epithelial barrier integrity, significantly different from the control group. 28 Ocular surface barrier lesion increases the penetration of allergens, bacteria and other substances, which increases susceptibility of AD patients to conjunctivitis. Furthermore, bacterial colonization of eyelids and conjunctival sac in AD patients was significantly higher, especially for Staphylococcus aureus.…”

“…Toll‐like receptor‐2 gene −16,934 A > T polymorphism, an important genetic predictor, was found to be involved in the occurrence of allergic conjunctivitis and AD with higher Total serum IgE 27 . A study revealed that patients with AD had lower tear film breakup time (TBUT) values and impaired conjunctival epithelial barrier integrity, significantly different from the control group 28 . Ocular surface barrier lesion increases the penetration of allergens, bacteria and other substances, which increases susceptibility of AD patients to conjunctivitis.…”

Highlights from the Journal of the European Academy of Dermatology and Venereology in 2022

“…Treatment with biologics such as Dupilumab often leads to ocular adverse effects including conjunctivitis. Many patients affected by atopic dermatitis, however, had ocular problems prior to commencing biological treatment, as evidenced by increased expression of filaggrin and claudin‐1 on the ocular surface of atopic dermatitis patients 22 …”

“…Many patients affected by atopic dermatitis, however, had ocular problems prior to commencing biological treatment, as evidenced by increased expression of filaggrin and claudin-1 on the ocular surface of atopic dermatitis patients. 22 Current research on atopic dermatitis is also focusing on the role of the cutaneous microbiome and a Swiss group has recently discovered an increased fungal diversity in severe atopic dermatitis. 23 Additionally, topical application of commensal bacteria, such as Vitreoscilla filiformis, appears to be beneficial for certain patients.…”

Biological Role of Chemerin in Inflammatory Skin Disease: Review Article

“…It is estimated that between 7 and 20% of children and 7 to 14% of adults are affected by this globally. 80% of individuals develop symptoms within the first five years of life, and 60% of them suffer a recurrence in maturity (4) .…”