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

Abstract

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.

Meibomian Gland Dysfunction: The Past, Present, and Future

“…Other groups of abnormal meibum such as seborrheic alone or seborrheic with meibomian seborrhea did not show a significant difference in the fatty acid chain composition of meibum compared with normal. 10 These results are contrary to those of Joffre et al 47 who showed a 60% decrease in saturated fatty acids and a 50% increase in hydrocarbon chain branching in meibum from MGD. Such large changes are well above the detection limit of infrared spectroscopy and yet, we did not observe them.…”

“…Shine and McCulley 10 have shown that meibum from donors with meibomian keratoconjunctivitis contains waxes and cholesterol esters and triglycerides 45 that are more saturated and contain less monounsaturated hydrocarbons 46 and branched hydrocarbon chains compared with meibum from normal donors. In contrast, Joffre et al 47 have shown that meibum from donors with MGD contains less saturation and more branching. Meibomian gland dysfunction meibum also contains higher levels of phosphatidylcholine, 48 phospholipid unsaturation, 49 wax esters, 25 and lower levels of phosphatidylethanolamine, sphingo- …”

The International Workshop on Meibomian Gland Dysfunction: Report of the Subcommittee on Tear Film Lipids and Lipid–Protein Interactions in Health and Disease

“…Infrared studies have shown that lipid order and phase transition temperatures are higher in meibum of donors with meibomian gland disease. 44 Recently, Joffre et al 74 demonstrated that the fatty acid profile of the excreta collected by Schirmer test strips in people with blepharitis is significantly different from controls. Total saturated fatty acids were 9.3% in those with blepharitis versus 24.6% in controls, with lower quantities of palmitic (C 16:0 ) and stearic (C 18:0 ) acids.…”

“…Only the mitochondrial dehydrogenase activity was significantly decreased in relation to the isoC 20 concentration increase. 74 Ocular rosacea has been associated with MGD. 97 The concentration of triglycerides and FFA, especially the mono-and polyunsaturated forms, is increased and may be responsible for the activation of neutrophils and inflammatory mediators.…”

“…Interestingly, small differences were observed in fatty acid composition between those with blepharitis and those with dry eye, with 50% more linoleic acid in the dry eye group. 74 The TF lipid layer changes secondary to MGD have a negative effect on the quality of vision measured as contrast sensitivity 94 and on evaporation of tears from the ocular surface. Gilbard et al 95 demonstrated in rabbits that meibomian occlusion resulted in a rise of tear osmolarity, possibly as a consequence of an increased evaporation rate of water from the TF.…”