Saturation of cholesteryl esters produced by human meibomian gland epithelial cells after treatment with rosiglitazone.

PURPOSE: The purpose of this study was to compare the cholesteryl ester (CE) profiles expressed from human meibomian gland epithelial cells (HMGECs) in response to rosiglitazone-induced differentiation to that of normal human meibum. METHODS: HMGECs were cultured with rosiglitazone (vehicle control, 20 μM, or 50 μM) and fetal bovine serum (FBS, 2% or 10%) for 2 days or 5 days. Following culture, lipid extracts were processed and analyzed by ESI-MSMS(ALL) in positive ion mode. CEs were identified using both LipidView 1.2 and PeakView 2.2 (SCIEX, Framingham, MA) and compared to literature reports of CEs in normal human meibum. RESULTS: There were 34 CEs with carbon number ranging from 14 to 34 detected from HMGECs. Across all conditions, HMGECs provided a CE profile that was 14.0% saturated, 60.6% monounsaturated, and 25.4% polyunsaturated. Culturing with 50 μM rosiglitazone and 2% FBS for 2 days resulted in the greatest number of upregulated saturated and monounsaturated CEs and downregulated polyunsaturated CEs. Five CEs were identified as being the most responsive to 50 μM rosiglitazone: CE 24:1, CE 28:1, CE 26:1, CE 18:1, and CE 22:1. CONCLUSION: Although differences in the CE profile exist between meibum and HMGECs, rosiglitazone promotes upregulation of highly expressed meibum-relevant CEs and shifts the saturation level toward a more meibum-like profile. The use of rosiglitazone as a differentiating agent is recommended in HMGEC research, and analysis by ESI-MSMS(ALL) is encouraged to differentiate meibum-relevant CEs from other nonpolar distractors detected by vital stains.