胆固醇结石病人肝脏胆小管侧膜ATP基因表达差异的研究

目的:本研究旨在测定比较胆石病人与对照组肝脏胆小管侧膜转运蛋白表达差异,以探讨胆石病发生的分子生物学机制。方法:研究包括20例胆囊胆固醇结石病人和11例无胆石症的对照。测定血清胆固醇和甘油三酯、胆汁胆固醇、胆汁酸和磷脂含量,采用Carey表计算胆汁胆固醇饱和指数。实时定量PCR法测定肝脏胆小管侧膜转运蛋白(ABCG5、ABCG8、ABCBll和ABCB4)mRNA的表达量。结果:胆石组血清胆固醇低于对照组(P<0.05)。胆石组胆汁胆固醇摩尔百分比和胆固醇饱和指数较对照组显著升高(P<0.01)。胆石组肝脏胆小管侧膜胆固醇转运蛋白ABCG5和ABCG8表达高于对照组,且后者差异具有统计学显著性(ABCG5:31.44±3.17Vs25.72±3.27,ABCG8:27.53±3.06vs17.81±2.23)。ABCBll和ABCB4表达在两组间差异无显著性。结论:本研究显示,胆石病主要病理生理异常为胆汁胆固醇过饱和,与肝脏胆小管侧膜胆固醇转运蛋白ABCG5和ABCG8的mRNA表达增加有关。

胆固醇结石病人肝脏脂质代谢异常的分子生物学研究

目的:研究导致胆石病人胆汁胆固醇过饱和的肝脏胆固醇和胆汁酸代谢途径中的分子生物学改变。方法:收集22例胆石病人和13例无胆石病的对照病人肝脏活检组织、胆囊胆汁和血浆。采用实时定量PCR检测肝脏基因表达,采用Western印迹法测定蛋白含量。结果:胆石病人较对照组ABCG5/ABCG8和LXRα基因的mRNA表达水平分别增加51%、59%和102%。肝脏SRBI的mRNA和蛋白含量均增加。结论:胆石病人ABCG5/ABCG8基因表达上调,可能与LXRα表达增加促进相关,这些异常是导致胆汁胆固醇过饱和的原因。此外,胆汁中过多的胆固醇可能来源于经肝脏高密度脂蛋白受体SRBI的摄取,而不是由于肝脏合成和酯化的异常。

High level of deoxycholic acid in human bile does not promote cholesterol gallstone formation

AIM: To study whether patients with excess deoxycholic acid (DCA) differ from those with normal percentage of DCA with respect to biliary lipid composition and cholesterol saturation of gallbladder bile.METHODS: Bile was collected during operation through puncturing into the gallbladder from 122 cholesterol gallstone patients and 46 gallstone-free subjects undergoing cholecystectomy. Clinical data, biliary lipids, bile acid composition,presence of crystals and nucleation time were analyzed.RESULTS: A subgroup of gallstone patients displayeda higher proportion of DCA in bile than gallstone free subjects.By choosing a cut-off level of the 90th percentile, a group of 13 gallstone patients with high DCA levels (mean 50percent of total bile acids) and a large group of 109 patients with normal DCA levels (mean 21 percent of total bile acids)were obtained. The mean age of the patients with high DCA levels was higher than that of the group with normal levels (mean age: 62 years vs45 years) and so was the mean BMI (28.3 vs. 24.7). Plasma levels of cholesterol and triglycerides were slightly higher in the DCA excess groups compared with those in the normal DCA group. There was no difference in biliary lipid composition, cholesterol saturation, nucleation time or occurrence of cholesterol crystals in bile between patients with high and normal levels of DCA.CONCLUSION: Gallstone patients with excess DCA were of older age and had higher BMI than patients with normal DCA. The two groups of patients did not differ with respect to biliary lipid composition, cholesterol saturation, nucleation time or occurrence of cholesterol crystals. It is concluded that DCA in bile does not seem to contribute to gallstone formation in cholesterol gallstone patients.

Gallbladder bile composition in patients with Crohn's disease

瞄准：进一步阐明高度的致病和机制在 Crohn 的疾病胆石冒形成的风险。方法：胆囊胆汁与 Crohn 的疾病从病人被获得为选任的外科被招收(17 与 ileal/ileocolonic 疾病并且 7 与 Crohn 的大肠炎) 。十四个胆石病人用作控制。十二指肠的胆汁与 ursodeoxycholic 酸在治疗前后从十个健康题目被获得。胆汁为胆汁的类脂化合物，胆汁酸，胆红素，晶体，和水晶察觉时间(CDT ) 被分析。胆固醇浸透索引是计算的。结果：胆红素的胆汁的集中比在有胆固醇胆石的病人在有 Crohn 的疾病的病人更高是大约 50% 。有 Crohn 包含回肠的疾病的十个病人和三那些与 Crohn 的大肠炎把胆固醇浸透胆汁。与 i 一起的四个病人忠实疾病并且那些之一在他们的胆汁与结肠的疾病显示了胆固醇晶体。大约有 Crohn 的疾病的病人的 1/3 有短 CDT。有 ursodeoxycholic 酸的健康题目的治疗没在十二指肠的胆汁增加胆红素的集中。有 Crohn 的疾病的几个病人，与或没有 i 忠实切除术 / 疾病把胆囊胆汁与胆固醇和短 CDT 使过饱和并且包含了胆固醇晶体。胆红素的胆汁的集中也不由于胆汁酸吸收不良可能与 Crohn 的大肠炎在病人被增加。结论：几个因素可能具有为与 Crohn 的疾病在病人开发胆固醇和颜料类型的胆石的高风险的重要性。

Bile acid formation in primary human hepatocytes

AIM To evaluate a culture system for bile acidformation in primary human hepatocytes incomparison with HepG2 cells.METHODS Hepatocytes were isolated fromnormal human liver tissue and were cultured inserum-free William’s E medium.The medium wascollected and renewed every 24 h.Bile acids andtheir precursors in media were finally analysed bygas chromatography-mass spectrometry.RESULTS Cholic acid(CA)andchenodeoxycholic acid(CDCA)conjugated withglycine or taurine accounted for 70% and 25% oftotal steroids.A third of CDCA was alsoconjugated with sulphuric acid.Dexamethasoneand thyroid hormone alone or in combination didnot significantly effect bile acid formation.Theaddition of cyclosporin A(10 μmol/L)inhibited thesynthesis of CA and CDCA by about 13% and30%,respectively.CONCLUSION Isolated human hepatocytes inprimary culture behave as in the intact liver byconverting cholesterol to conjugated CA andCDCA.This is in contrast to cultured HepG2 cells,which release large amounts of bile acidprecursors and unconjugated bile acids into themedium.

Analysis of ileal sodium/bile acid cotransporter and related nuclear receptor genes in a family with multiple cases of idiopathic bile acid malabsorption

The etiology of most cases of idiopathic bile acid malabsorption (IBAM) is unknown. In this study, a Swedish family with bile acid malabsorption in three consecutive generations was screened for mutations in the ileal apical sodium-bile acid cotransporter gene (ASBT; gene symbol, SLC10A2) and in the genes for several of the nuclear receptors known to be important for ASBT expression: the farnesoid X receptor (FXR) and peroxisome proliferator activated receptor alpha (PPARa). The patients presented with a clinical history of idiopathic chronic watery diarrhea, which was responsive to cholestyramine treatment and consistent with IBAM. Bile acid absorption was determined using 75Se-homocholic acid taurine (SeHCAT); bile acid synthesis was estimated by measuring the plasma levels of 7a-hydroxy-4-cholesten-3-one (C4). The ASBT, FXR, and PPARa genes in the affected and unaffected family members were analyzed using single stranded conformation polymorphism (SSCP), denaturing HPLC, and direct sequencing. No ASBT mutations were identified and the ASBT gene did not segregate withthe bile acid malabsorption phenotype. Similarly, no mutations or polymorphisms were identified in the FXR or PPARa genes associated with the bile acid malabsorption phenotype. These studies indicate that the intestinal bile acid malabsorption in these patients cannot be attributed to defects in ASBT. In the absence of apparent ileal disease, alternative explanations such as accelerated transit through the small intestine may be responsible for the IBAM.