MEIBOMIAN GLAND STUDIES - COMPARISON OF STEER AND HUMAN LIPIDS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 20  (4) , 522-536
Abstract
Simple surgery gave whole meibomian glands of steer yielding .apprx. 47 mg of lipid/pair of lids. This lipid gave a TLC pattern similar to that of steer or human excreta. Column chromatography of pooled steer gland lipids and pooled human lipid (excreta) gave 0.06 and 7.54% hydrocarbons, respectively, containing no squalene. Excluding human hydrocarbons (as exogenous material) the percentage composition of steer and human lipids were, respectively, sterol esters 31.7 and 29.5; wax esters 31.2 and 35.0; material in the diester region 11.4 and 8.4; triacyl glycerols 1.6 and 4.0; material in the post-triacyl glycerol region 2.8 and 3.2; free sterols 3.0 and 1.8; free fatty acids 5.1 and 2.1; and polar lipids 13.3 and 16.0. Glass capillary gas-liquid chromatography revealed the following: a series of normal odd- and even-chain hydrocarbons (C16-C32) for the steer and a complex pattern for the human samples; unsubstituted fatty acids in total lipids and various lipid classes ranging from C12-C31 with n-even, n-odd, iso-even and iso-odd and anteiso-odd chains for both samples; and fatty alcohols in total lipids and wax esters ranging from C18-C31. Anteiso structures predominated in the steer and iso structures in the human samples. Steer fatty acids favored anteiso branching and saturation; human acids favored iso branching and unsaturation. Fatty acids of sterol esters in both samples showed a wider range of chain lengths than did other lipid classes. Similarity of the fatty acid patterns suggests that the free fatty acids are derived from the triacyl glycerols as in human sebum. Identification of saturated fatty acids was confirmed by a GLC-mass spectrometry-data system (GLC-MS-DS). Meibum and meibocyte are defined as the meibomian gland equivalent of sebum and sebocyte.