Sömjen G J, Marikovsky Y, Wachtel E, Harvey P R, Rosenberg R, Strasberg S M, Gilat T
Department of Gastroenterology, Ichilov Hospital, Tel-Aviv University, Israel.
Biochim Biophys Acta. 1990 Jan 16;1042(1):28-35. doi: 10.1016/0005-2760(90)90052-y.
Cholesterol solubility and precipitation in bile are major factors in the pathogenesis of cholesterol gallstones. At present, mixed micelles and phospholipid vesicles are considered to be the only cholesterol carriers in bile. In this study we present evidence showing that phospholipid lamellae are major cholesterol carriers in human bile. Lamellae are a known aggregational form in pure phospholipid model systems. In the present study, lamellae were demonstrated by electron microscopy after negative staining and by small-angle X-ray diffraction in all human gallbladder bile samples examined. During diffraction experiments, cholesterol was found to crystallize from these lamellae. Cholesterol carriers in bile were separated by high-resolution chromatography and by prolonged ultracentrifugation. Lamellae were shown to solubilize most of the biliary cholesterol; vesicles solubilized a lesser amount; while micelles solubilized only a minor portion. Our data suggest that phospholipid aggregates are the main cholesterol carriers in bile. Bile salts may control the equilibrium between the various aggregational forms of cholesterol-carrying phospholipids.
胆固醇在胆汁中的溶解性和沉淀是胆固醇胆结石发病机制的主要因素。目前，混合微胶粒和磷脂囊泡被认为是胆汁中仅有的胆固醇载体。在本研究中，我们提供证据表明磷脂片层是人类胆汁中的主要胆固醇载体。片层是纯磷脂模型系统中一种已知的聚集形式。在本研究中，通过负染色后的电子显微镜和所有检测的人类胆囊胆汁样本中的小角X射线衍射证实了片层的存在。在衍射实验过程中，发现胆固醇从这些片层中结晶出来。通过高分辨率色谱法和长时间超速离心法分离胆汁中的胆固醇载体。结果显示，片层可溶解大部分胆汁胆固醇；囊泡溶解的量较少；而微胶粒仅溶解一小部分。我们的数据表明磷脂聚集体是胆汁中的主要胆固醇载体。胆盐可能控制携带胆固醇的磷脂各种聚集形式之间的平衡。
