Abstract：
Purpose: Changes in meibum composition and quantity in meibomian gland dysfunction (MGD) result in tear film instability and dry eye. This exploratory study aimed to identify changes in (O-acyl)-ω-hydroxy fatty acid (OAHFA) and hydrocarbon chain (HC) unsaturation levels in meibum related to the presence and severity of MGD. Methods: Meibum samples were collected from 3 cohorts of adults with no MGD, mild-to-moderate MGD, and severe MGD in a noninterventional clinical trial (NCT01979887). OAHFAs, cholesterol esters (CE), HC unsaturation, and HC length in the meibum samples were quantified with 1H-nuclear magnetic resonance spectroscopy using 2 methods of normalization. Results: Meibum samples from 62 subjects were analyzed: 21 non-MGD, 21 mild-to-moderate MGD, and 20 severe MGD. Meibum OAHFA and CE levels and HC unsaturation were reduced with increasing severity of MGD, with most pairwise comparisons significant (P < 0.05, t-tests), following the order non-MGD > mild-to-moderate MGD > severe MGD. Regardless of the resonances used for normalization, each pairwise comparison of OAHFA, CE, and HC unsaturation levels in MGD (combined severities) versus non-MGD samples was significant (P < 0.01, t-test). Analysis using various normalization equations showed reductions of 20%-22% for OAHFAs, 51%-57% for CE, and 36%-66% for HC unsaturation in MGD (combined severities) compared with non-MGD. HC length was not altered in MGD (combined severities) compared with non-MGD samples (t-test). Conclusions: Meibum OAHFA, CE, and HC unsaturation levels were reduced in MGD and were lowest in the severe MGD cohort. These findings may contribute to the understanding of the pathophysiology of MGD.
摘要：
目的：睑板腺功能障碍（MGD）中睑脂成分和数量的变化会导致泪膜不稳定和干眼。这项探索性研究旨在确定与MGD的存在和严重程度有关的meibum中（O-酰基）-ω-羟基脂肪酸（OAHFA）和烃链（HC）不饱和水平的变化。方法：从3个没有MGD的成人队列中收集了美脂样本，轻度至中度MGD，和严重MGD在一项非介入临床试验（NCT01979887）。OAHFAs,胆固醇酯（CE），HC不饱和度,使用2种归一化方法，通过1H-核磁共振波谱对meibum样品中的HC长度进行定量。结果：分析了62名受试者的美脂样本：21名非MGD，21轻度至中度MGD，和20个严重的MGD。OAHFA和CE水平和HC不饱和度随着MGD严重程度的增加而降低，大多数成对比较显著(P<0.05，t检验)，遵循非MGD>轻中度MGD>重度MGD的顺序。不管用于归一化的共振，OAHFA的每个成对比较，CE,MGD样品中的HC不饱和度水平(组合严重度)与非MGD样品中的HC不饱和度水平显著(P<0.01,t检验)。使用各种归一化方程的分析显示，OAHFAs的降低了20%-22%，51%-57%的CE，与非MGD相比，MGD中HC不饱和度(综合严重度)为36%-66%。与非MGD样品(t检验)相比,MGD(组合严重度)中的HC长度没有改变。结论:OAHFA,CE,和HC不饱和度水平在MGD中降低，在严重MGD队列中最低。这些发现可能有助于了解MGD的病理生理学。
