Meibomian gland dysfunction (MGD) represents a major cause of dry eye and ocular discomfort. Lipid mediators, often termed oxylipins, can be produced enzymatically or non-enzymatically, and may modulate inflammatory processes in MGD. Here, we aimed to assess the longitudinal changes of lipid mediators after various eyelid treatments (eyelid warming and thermopulsation) over 12 weeks. Secondly, we aimed to assess the chirality of mono-hydroxyl lipid mediators from tears of MGD and healthy participants.

Tears lipid mediators were extracted from Schirmer's strips and levels were quantified by liquid chromatography mass spectrometry (LC–MS) techniques. We quantified 33 lipid mediators in the tear, 18 of which (including 11-HETE, 20−OH-LTB₄, and 15-oxoETE) were reduced significantly after treatment. Changes in concentrations of 10-HDoHE (r = 0.54) and 15-oxoETE (r = 0.54) were correlated to the number of meibomian gland plugs at baseline, so increased severity of MGD was associated with treatment-induced change in lipid mediators.

The chiral analysis demonstrated that 5(S)-HETE, 12(S)-HETE, 15(S)-HETE, 14(S)-HDoHE, 17(S)-HDoHE and 11(R)-HETE were produced with significant enantiomeric excess (ee %) in controls compared to patients, due to enantiomer selective enzymatic action, whereas most lipid mediators were racemates in patients, due to dominance of oxidative effects which have no enantiomeric preference. Treatment of MGD restored the concentrations of 15(S)-HETE, 14(S)-HDoHE and 17(S)-HDoHE with significant ee values, suggesting reduction in oxidative action. Overall, MGD therapy reduced pro-inflammatory molecules generated by lipoxygenase and oxidative stress.

睑板腺功能障碍（MGD）是干眼和眼部不适的主要原因。脂质介质，通常称为氧脂素，可以通过酶促或非酶促方式产生，并且可以调节 MGD 中的炎症过程。在这里，我们的目的是评估 12 周内各种眼睑治疗（眼睑升温和热脉冲）后脂质介质的纵向变化。其次，我们的目的是评估 MGD 和健康参与者眼泪中单羟基脂质介质的手性。

从 Schirmer 试纸中提取泪液脂质介质，并通过液相色谱质谱 (LC-MS) 技术对泪液脂质介质进行定量。我们定量了泪液中的 33 种脂质介质，其中 18 种（包括 11-HETE、20−OH-LTB ₄和 15-oxoETE）在治疗后显着减少。 10-HDoHE (r = 0.54) 和 15-oxoETE (r = 0.54) 浓度的变化与基线时睑板腺栓的数量相关，因此 MGD 严重程度的增加与治疗引起的脂质介质的变化相关。

手性分析表明，5( S )-HETE、12( S )-HETE、15( S )-HETE、14( S )-HDoHE、17( S )-HDoHE 和 11( R )-HETE 的生成具有显着的产率。与患者相比，由于对映体选择性酶促作用，对照组中的对映体过量（ee%），而由于没有对映体偏好的氧化作用占主导地位，大多数脂质介质在患者中是外消旋体。 MGD 处理恢复了 15( S )-HETE、14( S )-HDoHE 和 17( S )-HDoHE 的浓度，并具有显着的 ee 值，表明氧化作用减少。总体而言，MGD 疗法减少了脂氧合酶和氧化应激产生的促炎分子。