Poster Presentation 14th Lorne Infection and Immunity 2024

The plight of the metabolite- metabolipidomic changes to the ocular surface in ocular allergy sufferers across seasons in Victoria, Australia (#107)

Esrin Aydin 1 2 , Moneisha Gokhale 2 , Serap Azizoglu 2 , Luke Chong 2 , Cenk Suphioglu 1
  1. NeuroAllergy Research Laboratory (NARL), School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
  2. School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia

Background: Ocular allergy (OA) is a localised subset of allergy characterised by ocular surface itchiness, redness and inflammation. Inflammation and eye-rubbing, due to allergy-associated itchiness, are common in OA sufferers and may trigger changes to the ocular surface biochemistry. The primary aim of this study is to assess differences in human tear metabolome and lipidome between OA sufferers and healthy controls (HC) across peak allergy (Spring-Summer) and off-peak season (Autumn-Winter) in Victoria, Australia.

Methods: 31 participants (22 OA sufferers, 9 healthy controls) aged 18-45 were recruited. Participants were grouped based on allergy symptom assessment questionnaire scoring. Metabolites and lipids were extracted from human tear samples and analysed using Mass Spectrometry. Data was analysed using TraceFinder, Metaboanalyst and IBM SPSS softwares.

Results: Metabolomics analysis showed 12 Differentially Expressed (DE) metabolites between OA and HC during peak allergy season, and 24 DE in off-peak season. Expression of niacinamide was significantly upregulated in OA vs HC across both seasons (p<0.05, Log2 fold-change>1.5). Lipidomics analysis showed 6 DE lipids between OA and HC during peak season, and 24 between OA and HC in off-peak season. In the off-peak season, (O-acyl) ω-hydroxy fatty acids (OAHFA) had a Log2 fold-changes up to 5.6 times higher in OA than HC. Comparison of HC across seasons showed 19 DE lipids (p<0.05, Log2 fold-change>1.5), including OAHFA, wax esters, phosphatidylcholines, sphingomyelins and lysophosphatidylethanolamines.

Conclusions: Tear metabolomics showed dysregulation of metabolites involved in cell structure, inflammation, and homeostasis between OA and HC across seasons, suggesting a possible link between OA-associated itch and ocular surface damage via eye-rubbing. Tear lipidome changes were minimal between OA and HC in peak season, but HC data across seasons suggested a protective role of the tear film on the ocular surface that may reduce the effects of airborne allergens on the lipidome during peak allergy season.