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.
“…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.…”
Section: Gn Foulks and D Borchmancontrasting
confidence: 85%
“…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- …”
Section: Changes In Meibum With Meibomian Gland Dysfunctionmentioning
Improved methods of spectroscopic and chemical analysis of the meibomian gland secretion in health and disease are providing a better understanding of the physical and chemical abnormalities of the meibomian gland secretions and are allowing better evaluation of medical therapies.
“…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.…”
Section: Gn Foulks and D Borchmancontrasting
confidence: 85%
“…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- …”
Section: Changes In Meibum With Meibomian Gland Dysfunctionmentioning
Improved methods of spectroscopic and chemical analysis of the meibomian gland secretion in health and disease are providing a better understanding of the physical and chemical abnormalities of the meibomian gland secretions and are allowing better evaluation of medical therapies.
“…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.…”
Section: Meibum Lipid Changes In Diseasementioning
confidence: 98%
“…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.…”
Section: Meibum Lipid Changes In Diseasementioning
confidence: 99%
“…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.…”
Section: Meibum Lipid Changes In Diseasementioning
Saturated branched chain fatty acids (BCFA) terminating with either a prop‐2‐yl (iso) or sec‐butan‐2‐yl (anteiso) group are common bioactive food components consumed from beef, fish, and dairy products. Little is known about the endogenous metabolism of BCFA and the enzymes mediating their interconversions. By using transient transfection studies, we report for the first time the substrate specificity of the elongase of very long chain fatty acids (ELOVL)1‐7 toward anteiso‐15:0 and iso‐18:0, and assessed competition between BCFA and normal saturated fatty acids (n‐SFA). ELOVL6 mediates elongation of anteiso‐15:0→anteiso‐17:0, while ELOVL3 is active toward iso‐18:0→iso‐20:0. Competition studies reveal n‐16:0 competes with anteiso‐15:0 for ELOVL6, while n‐18:0 competes with iso‐18:0 for ELOVL3. These competitions for elongation may have implications in specialized tissues where both BCFA and n‐SFA are present at comparable levels.
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