Liu Lei, Wang Zhen, Park Hui Gyu, Xu Chuang, Lawrence Peter, Su Xueli, Wijendran Vasuki, Walker W Allan, Kothapalli Kumar S D, Brenna J Thomas
College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan 410128, China; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
Prostaglandins Leukot Essent Fatty Acids. 2017 Jan;116:32-39. doi: 10.1016/j.plefa.2016.12.002. Epub 2016 Dec 10.
Branched chain fatty acids (BCFA) are constituents of gastrointestinal (GI) tract in healthy newborn human infants, reduce the incidence of necrotizing enterocolitis (NEC) in a neonatal rat model, and are incorporated into small intestine cellular lipids in vivo. We hypothesize that BCFA are taken up, metabolized and incorporated into human fetal cells in vitro.
Human H4 cells, a fetal non-transformed primary small intestine cell line, were incubated with albumin-bound non-esterified anteiso-17:0, iso-16:0, iso-18:0 and/or iso-20:0, and FA profiles in lipid fractions were analyzed.
All BCFA were readily incorporated as major constituents of cellular lipids. Anteiso-17:0 was preferentially taken up, and was most effective among BCFA tested in displacing normal (n-) FA. The iso BCFA were preferred in reverse order of chain length, with iso-20:0 appearing at lowest level. BCFA incorporation in phospholipids (PL) followed the same order of preference, accumulating 42% of FA as BCFA with no overt morphological signs of cell death. Though cholesterol esters (CE) are at low cellular concentration among lipid classes examined, CE had the greatest affinity for BCFA, accumulating 65% of FA as BCFA. BCFA most effectively displaced lower saturated FA. Iso-16:0, iso-18:0 and anteiso-17:0 were both elongated and chain shortened by ±C2. Iso-20:0 was chain shortened to iso-18:0 and iso-16:0 but not elongated.
Nontransformed human fetal intestinal epithelial cells incorporate high levels of BCFA when they are available and metabolize them in a structure specific manner. These findings imply that specific pathways for handling BCFA are present in the lumen-facing cells of the human fetal GI tract that is exposed to vernix-derived BCFA in late gestation.
支链脂肪酸（BCFA）是健康新生人类婴儿胃肠道的组成成分，可降低新生大鼠模型中坏死性小肠结肠炎（NEC）的发病率，并在体内被整合到小肠细胞脂质中。我们假设BCFA在体外可被人类胎儿细胞摄取、代谢并整合进去。
将人类H4细胞（一种胎儿非转化原代小肠细胞系）与白蛋白结合的非酯化反异-17:0、异-16:0、异-18:0和/或异-20:0一起孵育，并分析脂质组分中的脂肪酸谱。
所有BCFA都很容易作为细胞脂质的主要成分被整合进去。反异-17:0优先被摄取，并且在测试的BCFA中，它在取代正常（n-）脂肪酸方面最有效。异BCFA的优先顺序与链长相反，异-20:0出现的水平最低。BCFA在磷脂（PL）中的整合遵循相同的优先顺序，积累了42%的脂肪酸作为BCFA，且没有明显的细胞死亡形态学迹象。尽管在所检测的脂质类别中胆固醇酯（CE）的细胞浓度较低，但CE对BCFA的亲和力最大，积累了65%的脂肪酸作为BCFA。BCFA最有效地取代了较低的饱和脂肪酸。异-16:0、异-18:0和反异-17:0都通过±C2进行了链延长和链缩短。异-20:0链缩短为异-18:0和异-16:0，但没有链延长。
当有非转化的人类胎儿肠道上皮细胞时，它们会摄取高水平的BCFA并以结构特异性方式对其进行代谢。这些发现表明，在妊娠后期暴露于胎脂来源的BCFA的人类胎儿胃肠道面向管腔的细胞中存在处理BCFA的特定途径。
