Growth of Intestinal Epithelial Cells and Isoprenoid Pathway -Synthesis and Absorption of Sterol in Diabetes Mellitus-

1)与对照组大鼠相比，糖尿病大鼠配对喂食植物甾醇饲料后血浆植物甾醇水平升高，且与肠道形态学标志物以及肝素后血浆二胺氧化酶活性显著相关。由于植物甾醇在动物体内不能合成，这些结果表明肠道肥大和饮食因素在糖尿病高脂血症的病理生理中起重要作用。2）膜滤器上培养的Caco-2细胞胆固醇从顶侧向基底侧的转运受胰岛素调节，但不受酯化胆固醇积累的影响，表明肠上皮细胞中脂蛋白的组装和/或加工对于调节固醇的吸收是重要的。3）本文报告1例新诊断的谷甾醇血症伴发疹性黄瘤。HMG-CoA还原酶抑制剂可降低高胆固醇血症受试者的血浆植物甾醇水平，而胆汁螯合树脂则不能，这表明胆固醇生物合成速率的变化可能不会直接导致谷甾醇血症中血浆植物甾醇水平的升高。

1) Plasma levels of plant sterols were increased in diabetic rats pair-fed with plant sterol chow compared with control rats, and were significantly correlated with morphological markers of intestine as well as plasma post-heparin diamine oxidase activity. Since plant sterols are not synthesized in animals, these results suggest that hypertrophy of intestine and dietary factors play important roles in pathophysiology of hyperlipidemia in diabetic mellitus. Cholesterol synthetic rates were markedly increased in the intestine from diabetic rats fed with plant sterol chow.2) Cholesterol transport from apical side to basolateral side of Caco-2 cells cultured on membrane filter were regulated by insulin but not increased by accumulation of esterified cholesterol, suggesting that assembly and/or processing of lipoprotein in epithelial cells of gut is important for the regulation of absorption of sterols.3) A case of sitosterolemia with eruptive xanthoma was newly diagnosed. Administration of HMG-CoA reductase inhibitors decreased plasma plant sterol levels in hypercholesterolemic subjects, where bile sequestering resin did not, suggesting that changes of cholesterol biosynthetic rates may not directly rink to the increased levels of plasma plant sterol in sitosterolemia.