Marcelo C L, Duell E A, Rhodes L M, Dunham W R
University of Michigan Medical School, Department of Dermatology, Ann Arbor 48109-0528.
J Invest Dermatol. 1992 Dec;99(6):703-8. doi: 10.1111/1523-1747.ep12614196.
The polyunsaturated fatty acids linoleic acid (18:2, n-6) and arachidonic acid (20:4, n-6) are essential for normal skin function and structure, both as eicosanoid precursors and as components of lipids forming cell membranes. Adult human keratinocytes grow optimally in serum-free medium (MCDB 153) that contains no fatty acids. These keratinocytes expand rapidly and produce normal epidermis upon in vivo grafting. Analysis of lipid extracts of epidermis and of cultured keratinocytes was done to determine the fatty acid composition of cells grown in essential fatty acid (EFA)-deficient medium. Gas chromatography and high-performance liquid chromatography analyses were done of the fatty acids in the entire cell and in a thin-layer chromatography separated fraction containing those lipids that form cellular membranes. Comparison of snap-frozen epidermis and epidermal basal cell suspensions to passage 1 to 4 cultures shows that the cells are in an extreme essential fatty acid-deficient state by the first passage. The amount of the saturated fatty acids 16:0, 18:0, and 14:0 is unchanged by culture. The polyunsaturated fatty acids are found to be significantly decreased, the cells balancing their lack with a significant increase in the relative abundance of the monounsaturated fatty acids, 18:1 and 16:1. Greater than 85-90% of the fatty acids was found in lipids associated with membranes and no unusual fatty acids were detected. Because the serum-free medium is fatty acid free and the cells cannot synthesize essential fatty acids, the rapid division of the cells results in the predominance of an extreme EFA-deficient cell type. The essential fatty acid-deficient keratinocyte is an excellent adult, normal epidermal cell model that can be used to study EFA deficiency and the effect of the eicosanoid and fatty acids on cell function and structure.
多不饱和脂肪酸亚油酸（18:2，n-6）和花生四烯酸（20:4，n-6）对于正常皮肤功能和结构至关重要，它们既是类二十烷酸前体，也是构成细胞膜的脂质成分。成人角质形成细胞在不含脂肪酸的无血清培养基（MCDB 153）中生长最佳。这些角质形成细胞在体内移植后能迅速增殖并形成正常表皮。对表皮和培养的角质形成细胞的脂质提取物进行分析，以确定在缺乏必需脂肪酸（EFA）的培养基中生长的细胞的脂肪酸组成。对整个细胞以及通过薄层色谱分离的含有构成细胞膜脂质的部分进行了气相色谱和高效液相色谱分析。将速冻表皮和表皮基底细胞悬液与传代1至4代的培养物进行比较，结果表明细胞在首次传代时就处于极度必需脂肪酸缺乏状态。饱和脂肪酸16:0、18:0和14:0的含量在培养过程中未发生变化。发现多不饱和脂肪酸显著减少，细胞通过显著增加单不饱和脂肪酸18:1和16:1的相对丰度来平衡其缺乏。超过85%-90%的脂肪酸存在于与膜相关的脂质中，未检测到异常脂肪酸。由于无血清培养基不含脂肪酸且细胞无法合成必需脂肪酸，细胞的快速分裂导致极度缺乏必需脂肪酸的细胞类型占主导。缺乏必需脂肪酸的角质形成细胞是一种优秀的成人正常表皮细胞模型，可用于研究必需脂肪酸缺乏以及类二十烷酸和脂肪酸对细胞功能和结构的影响。
