title: Longitudinal changes in tear fluid lipidome brought about by eyelid-warming treatment in a cohort of meibomian gland dysfunction.
abstract: Meibomian gland dysfunction (MGD) is a leading cause of evaporative dry eye and ocular discomfort characterized by an unstable tear film principally attributed to afflicted delivery of lipids to the ocular surface. Herein, we elucidated longitudinal tear lipid alterations associated with disease alleviation and symptom improvement in a cohort of MGD patients undergoing eyelid-warming treatment for 12 weeks. Remarkably, eyelid-warming resulted in stark reductions in lysophospholipids (P < 0.001 for lyso-plasmalogen phosphatidylethanolamine, lysophosphatidylcholine, and lysophosphatidylinositol), as well as numerous PUFA-containing diacylglyceride species in tears, accompanied by significant increases in several PUFA-containing phospholipids. These changes in tear lipidomes suggest that eyelid-warming leads to diminished activity of tear phospholipases that preferentially target PUFA-containing phospholipids. In addition, treatment led to appreciable increases (P < 0.001) in O-acyl-ω-hydroxy-FAs (OAHFAs), which are lipid amphiphiles critical to the maintenance of tear film stability. Longitudinal changes in the tear lipids aforementioned also significantly (P < 0.05) correlated with reduced rate of ocular evaporation and improvement in ocular symptoms. The foregoing data thus indicate that excess ocular surface phospholipase activity detrimental to tear film stability could be alleviated by eyelid warming alone without application of steroids and identify tear OAHFAs as suitable markers to monitor treatment response in MGD.
authors.affiliation: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China Department of Biological Sciences, National University of Singapore, Singapore.
authors.forename: Sin Man
authors.initials: SM
authors.lastname: Lam
authors.affiliation: Singapore Eye Research Institute, Singapore Singapore National Eye Centre, Singapore Duke-National University of Singapore Graduate Medical School, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
authors.affiliation: Life Sciences Institute, National University of Singapore, Singapore.
authors.forename: Xinrui
authors.initials: X
authors.lastname: Duan
authors.affiliation: Biomedical Engineering Department, Ngee Ann Polytechnic, Singapore.
authors.forename: U Rajendra
authors.initials: UR
authors.lastname: Acharya
authors.affiliation: Biomedical Engineering Department, Ngee Ann Polytechnic, Singapore.
authors.forename: Jen Hong
authors.initials: JH
authors.lastname: Tan
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Andrea
authors.initials: A
authors.lastname: Petznick
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore.
authors.forename: Markus R
authors.initials: MR
authors.lastname: Wenk
authors.affiliation: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Guanghou
authors.initials: G
authors.lastname: Shui
mesh_terms: D015352:Dry Eye Syndromes / Q000378:metabolism* / Q000628:therapy; D006801:Humans; D006979:Hyperthermia, Induced; D050356:Lipid Metabolism; D008137:Longitudinal Studies; D008537:Meibomian Glands / Q000378:metabolism* / Q000503:physiopathology; D055442:Metabolome; D013666:Tears / Q000378:metabolism*; D008055:Lipids
chemical_list: D008055:Lipids
keywords: O-acyl-omega-hydroxy fatty acids; dry eye; lysophospholipids; tear lipidomics