Ocular surface toll like receptors in ageing

BACKGROUND: To evaluate changes in Toll Like Receptors (TLRs) expression at the ocular surface of healthy volunteers within different age groups. METHODS: Fifty-one healthy volunteers were enrolled in a pilot observational study. Clinical function tests (OSDI questionnaire, Schirmer test type I and Break Up time) were assessed in all subjects. Temporal Conjunctival imprints were performed for molecular and immunohistochemical analysis to measure TLRs expression (TLR2, 4, 3, 5, 7, 8, 9 and MyD88). RESULTS: Immunofluorescence data showed an increased TLR2 and decreased TLR7 and TLR8 immunoreactivity in old conjunctival imprints. Up-regulation of TLR2 and down-regulation of TLR7, TLR8 and MyD88 transcripts expression corroborated the data. A direct correlation was showed between increasing ICAM-1 and increasing TLR2 changes with age. Within the age OSDI score increases, T-BUT values decrease, and goblet cells showed a decreasing trend. CONCLUSION: Changes in TLRs expression are associated with ageing, suggesting physiological role of TLRs in modulating ocular surface immunity. TLRs age related changes may participate to the changes of ocular surface homeostatic mechanisms which lead to inflammAging.