Tear Function and Ocular Surface MUC5AC, MUC16 mRNA Alterations in Patients With Atopic Keratoconjunctivitis

Abstract

Purpose:: To investigate the alterations in tear functions and ocular surface MUC5AC and MUC16 mRNA expression in patients with atopic keratoconjunctivitis (AKC) and healthy control subjects

Methods:: Thirty-six eyes of 18 patients (16 males, 2 females; mean age:29.5 years) with AKC were studied. 32 eyes of 16 healthy control subjects (8 males, 2 females; mean age: 27.5 years) with no history of contact lens wear and ocular disease were also investigated. All subjects underwent measurements of tear film break up, Cochet-Bonnet corneal sensitivity, fluorescein and Rose Bengal vital stainings, conjunctival impression cytology for PAS staining and MUC 5AC and MUC16 immunohistochemistry stainings. Conjunctival brush cytology was also performed to assess the percentages of inflammatory cells and MUC5AC ,MUC16 mRNA expressions in Real Time RT-PCR. Ethic board review and Informed consents were obtained and the study followed the Guidelines of the Tenets and Declaration of Helsinki.

Results:: The mean corneal sensitivity and BUT values were significantly lower in AKC compared to controls. Vital staining scores were significantly higher in AKC compared to the control subjects (p<0.01).Brush cytology specimens revealed significantly higher inflammatory cell infiltration in AKC. Impression cytology showed higher grade of squamous metaplasia and a significant decrease of goblet cell density in AKC compared to controls (p<0.01) .MUC5ACmRNA expression was significantly decreased with a significant concomitant increase in MUC 16 mRNA expression in AKC relative to controls.

Conclusions:: The ocular surface disease in AKC was characterized with a considerable degree of tear instability and ocular surface epithelial damage. MUC 16 mRNA was thought to be upregulated in response to the downregulation goblet cell MUC5ACmRNA with an attempt to protect the ailing ocular surface health.

Keywords: cornea: surface mucins • cornea: tears/tear film/dry eye • cornea: clinical science