Branched-chain fatty acids, increased in tears of blepharitis patients, are not toxic for conjunctival cells

Abstract

AIM: The composition of the meibum of blepharitis patients is characterised by increased levels of branched-chain fatty acids (BCFAs) that return to normal values in patients treated with cyclins and lid hygiene. The aim of this study was to determine if BCFAs had toxic effects on conjunctival cells related to the disease. METHODS: Chang and IOBA-NHC conjunctival human cells were treated with BCFAs (isoC16 and isoC20) or palmitic acid as a control for 4 h or 24 h at 50 microM or 100 microM. Morphological and functional changes were investigated by measuring mitochondrial dehydrogenase activity, cell permeability, mitochondrial depolarisation, chromatin condensation, IL-1beta and reactive oxygen species production. RESULTS: None of the fatty acids modified the parameters of cytotoxicity in conjunctival cells in Chang or IOBA-NHC cell lines. Only the mitochondrial dehydrogenase activity was significantly decreased in relation to the isoC20 concentration increase. CONCLUSIONS: The increase in BCFAs in the tears of blepharitis patients does not consistently participate in the conjunctival cell changes throughout the course of the disease. Instead, it is likely an adaptive response of the ocular surface to the lack of tears, possibly increasing meibum fluidity, thus enhancing lacrimal film stability.