Caffeine prevents cholesterol gallstone formation

Methylxanthines are known to inhibit in vitro gallbladder absorption. Increased gallbladder absorption has been observed during formation of cholesterol gallstones. Therefore we tested the hypothesis that caffeine would inhibit in vivo gallbladder absorption and thus prevent formation of cholesterol gallstones. Sixteen adult male prairie dogs received a control nonlithogenic diet, and 16 were fed a diet containing 1.2% cholesterol. Half of the animals in each group received caffeine in their drinking water. Gallbladder and hepatic bile were examined microscopically and analyzed for biliary lipids and electrolytes. The gallbladder/hepatic bile ratios of bile acids and sodium were calculated as indices of gallbladder absorption. All eight animals receiving the 1.2% cholesterol diet formed cholesterol gallstones, whereas none of the eight animals fed the cholesterol diet plus caffeine formed gallstones. The cholesterol saturation index was similar, however, in both groups. In animals fed a control diet, the administration of caffeine significantly increased hepatic bile flow and decreased the gallbladder/hepatic bile ratio for both bile acids (5.4 +/- 0.9 vs 3.6 +/- 0.3; p less than 0.05) and sodium (1.26 +/- 0.03 vs 1.12 +/- 0.03; p less than 0.01). In animals fed the high-cholesterol diet, caffeine significantly decreased the ratios for both bile acids (9.0 +/- 1.6 vs 5.3 +/- 0.6; p less than 0.05) and sodium (1.37 +/- 0.06 vs 1.21 +/- 0.01; p less than 0.05), lowered gallbladder bile protein levels, normalized gallbladder stasis, and lowered serum cholesterol levels. In summary, caffeine prevented formation of cholesterol gallstones in this experimental model. The effect of caffeine may be the result of alterations in multiple biliary parameters including the inhibition of gallbladder absorption.     

Oral calcium promotes pigment gallstone formation

Dietary calcium supplementation has been recommended for prevention of osteoporosis and has become a standard component of most "health food" diets. Biliary calcium has been recognized to play a central role in the formation of pigment gallstones. We have recently demonstrated that 5 days of oral calcium supplementation significantly increases biliary calcium in the prairie dog (K. D. Lillemoe, T. H. Magnuson, G. E. Peoples, et al., Gastroenterology 94: A563, 1988). We hypothesized, therefore, that long-term oral calcium supplementation would promote pigment gallstone formation. Sixteen adult male prairie dogs were maintained on a standard nonlithogenic diet. Eight animals received calcium supplementation (2.5 x control levels) in their water, while the remaining eight animals served as controls. After 8 weeks, cholecystectomy was performed, and the common bile duct was cannulated. Bile was examined microscopically and analyzed for ionized calcium, bilirubin, glycoprotein, and biliary lipids. The cholesterol saturation index (CSI) was calculated. Pigment stones and calcium bilirubinate sludge were present in all animals receiving calcium supplementation. Only one control animal had evidence of pigment stones (P less than 0.001). Biochemical analysis of gallbladder bile demonstrated a significant increase in total bilirubin and bilirubin monoglucuronide (P less than 0.01) as well as bile glycoprotein content (P less than 0.05) after oral calcium supplementation. Gallbladder bile ionized calcium was also increased although not significantly. These data suggest that oral calcium supplementation promotes gallbladder sludge and pigment gallstone formation in the prairie dog. This observation raises concern that oral calcium supplementation, especially in the older female population, may enhance gallstone formation.     

载脂蛋白E与胆囊胆固醇结石关系的研究

目的 探讨载脂蛋白Ｅ（ａｐｏｌｉｐｏｐｒｏｔｅｉｎ Ｅ）基因多态性与胆囊胆固醇结石形成的关系。方法 应用聚合酶链反应（ＰＣＲ）技术检测６０例健康人和４０例胆囊胆固醇结石患者的Ａｐｏ Ｅ基因多态性及等位基因频率。结果 胆囊胆固醇结石患者Ａｐｏ Ｅ基因型Ｅ３／４的频率２３％（９／４０）明显高于健康对照组７％（４／６０）（Ｐ〈０．０５）,胆囊胆固醇结石患者组ε４等位基因频率为１５％（１２／８０）,明显高     

Alcohol protects against cholesterol gallstone formation.

Epidemiologic studies have suggested that alcohol intake may protect against cholelithiasis. Gallstone formation was studied in 20 prairie dogs fed a 0.4% cholesterol-supplemented liquid diet. In ten animals, ethanol provided 35% of total calories. In ten pair-fed controls, ethanol was replaced with isocaloric maltose. After 3 months the gallbladders were inspected for gallstones, and gallbladder bile was analyzed. Cholesterol macroaggregates were present in all controls and pigment concretions were noted in five. No stones were observed in ethanol-fed animals. Bile in the ethanol group contained less cholesterol than the controls (5.60 +/- 0.71 vs. 9.16 +/- 0.61 mmol/L, p less than 0.05) while phospholipids, total bile acids, and bilirubin were unchanged. The resulting cholesterol saturation index was reduced in the ethanol group (0.81 vs. 1.22, p less than 0.05). The ratios of trihydroxy to dihydroxy bile acids were also different (2.07 +/- 0.25 in ETOH vs. 3.29 in controls, p less than 0.05). The bile calcium concentration was higher in control animals presumably secondary to the use of complex sugars (5.36 +/- 0.37 vs. 3.77 +/- 0.32 mmol/L, p less than 0.05). These results confirm that ethanol inhibits cholesterol gallstone formation. They further suggest that this effect is dependent on reductions of biliary cholesterol and selective changes in bile acid concentrations.     

胆囊结石中胆固醇代谢变化的实验研究

目的　探讨胆囊结石的胆固醇代谢变化。方法　采用高胆固醇膳食诱发兔胆囊结石模型 ,对进食高胆固醇膳食后 1,2 ,3,4周实验组和对照组血清脂蛋白胆固醇、肝脏总胆固醇 (HTC)、胆汁中胆固醇 (BC)和甘氨胆酸 (GCA) ,肝细胞低密度脂蛋白受体活性变化进行了动态研究。结果　高胆固醇膳食后 ,1周开始出现胆囊结石 ,2 ,3和 4周分别有 40 % ,6 0 % ,70 %出现胆囊结石。血清总胆固醇 (TC) ,甘油三酯 (TG ) ,磷脂 (PL) ,低密度脂蛋白胆固醇(LDL C)和极低密度脂蛋白胆固醇 (VLDL C) ,HTC ,BC均逐渐明显升高 (与对照组比较P均<0 .0 5 ) ;高密度脂蛋白胆固醇及其亚组分 (HDL C ,HDL2 C ,HDL3 C)有降低趋势 ,但无显著性差异 (P >0 .0 5 ) ;GCA逐渐降低 ,以 3周和 4周时明显 (P <0 .0 5 ) ;12 5I LDL与肝细胞低密度脂蛋白受体 (LDLr)最大结合力 (Bmax)在 1周组略升高 (P <0 .0 5 ) ,2周组逐渐下降 ,3周和 4周组时明显下降 (P <0 .0 5 ) ,解离常数Kd值逐渐升高 ,以 3周和 4周组明显 (P <0 .0 5 )。结论　随着高胆固醇膳食进食时间延长 ,血清及肝脏中胆固醇均增加 ,胆汁中胆固醇增加 ,肝细胞低密度脂蛋白受体活性下降 ,可能致胆汁中甘氨胆酸合成减少 ,成石性胆汁形成。提示胆固醇代谢中不同环节的变化均可在胆囊结石中     

Gallbladder absorption increases during early cholesterol gallstone formation

The hypothesis that the presence of cholelithogenic bile during the early stages of cholesterol gallstone formation promotes gallbladder absorption of water and electrolytes was tested in a prairie dog gallstone model. An increase in gallbladder transport of water and sodium was observed in cholesterol-fed prairie dogs at a time when cholesterol crystals were present, but before gallstone formation. These data suggest that in the presence of cholesterol-saturated bile, in vivo gallbladder absorption is increased during the early stages of cholesterol gallstone formation. The resulting increase in the solute concentration may promote nucleation and, therefore, be an important etiologic factor in cholesterol gallstone formation.     

Biliary lipids alter ion transport during cholesterol gallstone formation

Recent studies indicate that gallbladder absorption increases during the early stages of experimentally induced cholesterol gallstone formation. The purpose of the present study was to ascertain whether this change results from an alteration in gallbladder mucosal function per se or is a response of an otherwise healthy mucosa to the presence of cholelithogenic bile. Prairie dogs were fed either a control chow or a 1.2% cholesterol-enriched chow for 9 (Pre-GS) or 21 (Chronic-GS) days. Gallbladders were mounted in an Ussing-type chamber and electrophysiologic indices of ion transport were determined. Mucosal function was assessed independently by exposing the gallbladder to Ringer's solution in the absence of biliary lipids. Ion transport was similar in control and Pre-GS gallbladders but was significantly reduced in Chronic-GS animals. Gallbladders were subsequently exposed to model bile solutions containing bile acids and phospholipids in concentrations selected so as to reflect the relative concentration of bile salts and phospholipids in normal and cholesterol gallstone animals. The cross-comparison of control gallbladders exposed to nonlithogenic bile with Pre-GS gallbladders exposed to model cholelithogenic bile, therefore, simulates the in vivo situation and directly assesses the role of biliary lipids as a determinant of ion transport. When this comparison was performed there was a significant increase in short-circuit current (P less than 0.05) and potential difference (P less than 0.05) in Pre-GS animals as compared to controls. We propose that the increase in gallbladder absorptive function results from exposure of an otherwise healthy, functioning mucosa to cholelithogenic bile, and not from a change in mucosal function per se.     

Soluble dietary fiber protects against cholesterol gallstone formation.

BACKGROUND: Epidemiological studies have suggested that soluble dietary fibers are hypocholesterolemic and may inhibit cholelithiasis. METHODS: Thirty prairie dogs were placed on a cholesterol-supplemented lithogenic diet. Ten animals received 5% psyllium (PSY) and 10 animals received 5% cellulose. After 6 weeks all gallbladders were inspected for stones; blood and bile were collected for analysis. RESULTS: Cholesterol stones were present in 8 of 10 of the control animals, in 6 of 10 of the cellulose group, and 3 of 10 of the PSY animals (P <0.05). Concentrations of cholesterol and chenodeoxycholic acid (CDCA) were significantly lower in the PSY group compared with controls (0.49 versus 0.88 mM and 4.2 versus 9.2 mM, respectively) leading to a significant reduction in the cholesterol saturation index (0.62 versus 1.2). CONCLUSIONS: A dietary soluble fiber (PSY) inhibits cholesterol stone formation by reducing the biliary cholesterol saturation index. This protective effect is associated with a selective decrease in biliary cholesterol and CDCA.     

Effects of cholecystokinin on gallbladder stasis and cholesterol gallstone formation

Recent studies suggest an etiologic role for gallbladder stasis in the genesis of cholesterol gallstones. The effect of periodic gallbladder emptying on stone prevention is not clear. Using the prairie dog model, we tested the hypothesis that daily cholecystokinin-octapeptide (CCK-OP) prevents gallbladder stasis and cholesterol gallstone formation. Prairie dogs were fed either a control or a 0.4% cholesterol-enriched chow for 6 weeks. Cholesterol-fed animals received a daily intramuscular injection of either saline, CCK-OP, 0.2 μg/kg or CCK-OP, 1.0 μg/kg. Gallbladder bile lithogenic index (LI), bile salt pool size (BSPS), and the degree of radioisotope equilibration between gallbladder and hepatic bile (Rsa-an index of stasis) were determined. The more physiologic dose of CCK-OP (0.2) significantly reduced BSPS and bile lithogenicity, prevented stasis and reduced the incidence of gallstones. Our data suggest that (1) periodic gallbladder emptying decreases bile lithogenicity, prevents stasis, and reduces the incidence of cholelithiasis, (2) stasis is essential to gallstone formation and (3) daily physiologic doses of CCK-OP may be useful for gallstone prophylaxis in high-risk patients.     

胆汁中氨肽酶N的分离提纯及其成核作用的研究

目的 从胆石症病人胆汁中分离,提纯氨肽麦Ｎ（ａｍｉｎｏｐｅｐｔｉｄａｓｅ ｎ,ＡＰＮ）,观察其成核活性,并探讨熊去氧胆酸对ＡＰＮ的影响。方法 应用ＣｏｎＡ亲和层析法、羟基磷灰石柱层析及高压液相离子交换柱法分离提纯胆汁中的ＡＰＮ,并用模拟胆汁系统观察ＡＰＮ的成核活性及比较胆固醇结石组、熊去氧胆酸（ｕｒｓｏｄｅｏｘｙｃｈｏｌｉｃ ａｃｉｄ,ＵＤＣＡ）组及对照组胆汁中各种成分的变化。结果 ＡＰＮ的纯化倍     

Ezetimibe抑制胆固醇结石形成的实验研究

目的 探讨ezetimibe（Eze）对胆囊胆固醇结石形成的抑制作用。方法 将30只雄性成年C57BL/6小鼠随机分为普通饲料喂养(chow)组、成石饲料喂养(LD)组和成石饲料加Eze组[Eze 5 mg/（kg·d）灌胃]。饲养8周后收集血清、肝脏、小肠和胆囊。观察胆囊内胆固醇结石形成情况。采用酶法测定血清、胆汁成分、肝组织胆固醇含量。采用实时定量PCR测定肝脏和小肠胆固醇代谢相关基因mRNA相对表达量。结果 chow组小鼠胆囊内未发现结石形成。LD组小鼠胆囊结石形成率为100%。Eze组完全无结石形成。Eze组小鼠小肠胆固醇吸收率(9.29%±4.32%),较LD组(58.62%±3.10%)和chow组(56.42%±2.67%)均显著降低（P<0.01）。LD组血清胆固醇[(4.99±0.50) mmol/L]和肝组织胆固醇含量[(22.92±2.39) mg/g]均较chow组[(2.87±0.06) mmol/L和(2.45±0.08) mg/g]显著增加（P<0.05）。Eze组血清胆固醇[(1.11±0.10） mmol/L]和肝组织胆固醇含量[(2.70±0.07) mg/g]均较LD组显著降低（P<0.05）。LD组小鼠胆汁胆固醇含量[LD组(10.87±1.46) mmol/L比chow组(3.67±0.58) mmol/L]和胆固醇饱和指数[LD组(1.42±0.19)比chow组(0.59±0.02)]显著增加。Eze组胆汁胆固醇含量[(2.72±0.29) mmol/L]和胆固醇饱和指数(0.57±0.07)均较LD组显著降低（P<0.01）。结论 Eze抑制小肠胆固醇肠道摄取,具有预防胆囊胆固醇结石形成的作用。     

The effects of amiloride on biliary calcium and cholesterol gallstone formation.

Recent studies indicate that gallbladder absorption increases during the early stages of experimentally-induced cholesterol gallstone formation. The purpose of the present study was to ascertain whether pharmacologic inhibition of gallbladder ion transport and absorption reduces the incidence of experimentally-induced cholesterol gallstones. Prairie dogs were fed either a control chow or a 1.2% cholesterol-enriched chow for 15 days. One group of cholesterol-fed animals received saline via an orogastric tube; another group received amiloride, a drug known to inhibit in vitro ion transport in the prairie dog gallbladder. The incidence of gallstones in cholesterol-fed animals was reduced from 83% to 13% (p less than 0.025) when the animals were treated with amiloride; this occurred despite a cholesterol-saturation index comparable to that observed in gallstone animals. Additionally, although biliary calcium decreased in the gallbladder, hepatic bile did not in the amiloride-treated animals. These data provide further evidence that altered gallbladder absorption and increased biliary calcium are important factors in the pathogenesis of cholesterol gallstones.     

肠道菌群通过影响胆汁酸代谢参与胆囊胆固醇结石形成

胆囊结石是一种常见病、多发病,据统计约10%～15%的成年人患有胆囊结石。大多数（90%）胆囊结石属于胆固醇结石,目前胆固醇结石的发生机制仍不十分清楚,有研究认为肠道微生态失调在胆固醇结石形成中发挥了重要作用。正常情况下,肠道菌群保持稳态与宿主是互利共生的关系,参与物质与能量的代谢,促进免疫系统发育与成熟,形成屏障保护宿主免受病原体的攻击,有助于人体内稳态调节。然而,一旦这种平衡被打破,就可能引起疾病的发生,包括结肠炎、结肠癌和胆囊结石等。近年来研究发现胆囊结石患者的肠道微生态处于失衡状态,这种菌群失衡影响胆汁酸的肝肠循环,导致胆汁酸和胆固醇代谢紊乱,这可能是胆固醇结石发生的重要一环。本文主要概括了胆固醇结石形成与肠道微生态的关系以及肠道菌群如何影响胆汁酸代谢。     

Altered bile composition during cholesterol gallstone formation: cause or effect?

Gallbladder stasis, increased gallbladder absorption, and elevated biliary levels of calcium, hydrogen ion, and bilirubin have been implicated as factors potentially critical to cholesterol crystal precipitation. Previous studies, however, have analyzed bile only when crystals or gallstones have already formed. Therefore, we tested the hypothesis that changes in bile composition are a late effect, occurring only after crystal formation. Adult male prairie dogs were fed a standard nonlithogenic control diet (n = 7) or a lithogenic 1.2% cholesterol diet for 5, 9, or 14 days to cause cholesterol saturation (n = 7), cholesterol monohydrate crystals (n = 7), or gallstones (n = 7). Gallbladder bile was examined microscopically for crystals, and analyzed for ionized calcium, bilirubin, pH, total protein, and biliary lipids. The ratio of gallbladder to hepatic bile radiolabeled cholic acid specific activity (Rsa) was calculated as an index of gallbladder stasis. Cholesterol saturation index was calculated. The results demonstrate that increased gallbladder bile cholesterol saturation and total protein concentration precede cholesterol monohydrate crystal precipitation. However, changes in gallbladder ionized calcium, unconjugated bilirubin, pH, stasis, and absorption were noted only after crystals and gallstones had already formed. These data indicate that alterations in gallbladder bile calcium, bilirubin, pH, stasis, and absorption are not early changes, but occur simultaneously with or after crystal formation. Increased biliary protein, however, which was elevated prior to nucleation, may be an important mediator of cholesterol precipitation in cholesterol-saturated bile.     

胆固醇对胆固醇结石形成和胆囊离体肌条的影响

目的 探讨胆固醇与胆囊动力的关系及其在胆固醇结石形成中的作用.方法 构造豚鼠胆固醇结石模型,检测各组豚鼠血清胆固醇(TC)及胆汁胆固醇(BC)含量;利用灌流法加药,张力换能器记录胆囊收缩素对各组离体胆囊肌条张力的变化,并初步探讨胆固醇对胆囊肌条的作用机制.结果 A组(正常豚鼠)无结石发生,B、C两组(致石饲料4周、8周)共有13例结石发生;B、C两组TC和BC升高(与A组相比P<0.05),加入CCK后收缩振幅均增加,呈浓度依赖性.且与TC、BC相关(P<0.05);同A组相比,B、C及D(胆固醇孵育后胆囊肌条)三组对CCK效应值变小,起作用时间慢(P<0.05);CCK对胆囊离体肌条的作用可以部分被胆固醇抑制(变化为69.2%,P<0.05),而胆固醇的影响可以部分被阿托品、尼莫地平抑制(变化分别为64.2%、62.1%,P<0.05),不被TTX影响(P>0.05).结论 TC及BC增高的同时胆囊肌条肌张力降低及对CCK的敏感性降低,成石率增高;胆固醇孵育后肌条肌张力降低及对CCK的敏感性降低;胆固醇可能与胆囊动力及胆固醇结石形成相关.     

胆固醇对胆固醇结石形成和胆囊离体肌条的影响

目的 探讨胆固醇与胆囊动力的关系及其在胆固醇结石形成中的作用.方法 构造豚鼠胆固醇结石模型,检测各组豚鼠血清胆固醇(TC)及胆汁胆固醇(BC)含量;利用灌流法加药,张力换能器记录胆囊收缩素对各组离体胆囊肌条张力的变化,并初步探讨胆固醇对胆囊肌条的作用机制.结果 A组(正常豚鼠)无结石发生,B、C两组(致石饲料4周、8周)共有13例结石发生;B、C两组TC和BC升高(与A组相比P<0.05),加入CCK后收缩振幅均增加,呈浓度依赖性.且与TC、BC相关(P<0.05);同A组相比,B、C及D(胆固醇孵育后胆囊肌条)三组对CCK效应值变小,起作用时间慢(P<0.05);CCK对胆囊离体肌条的作用可以部分被胆固醇抑制(变化为69.2%,P<0.05),而胆固醇的影响可以部分被阿托品、尼莫地平抑制(变化分别为64.2%、62.1%,P<0.05),不被TTX影响(P>0.05).结论 TC及BC增高的同时胆囊肌条肌张力降低及对CCK的敏感性降低,成石率增高;胆固醇孵育后肌条肌张力降低及对CCK的敏感性降低;胆固醇可能与胆囊动力及胆固醇结石形成相关.     

绞股蓝预防豚鼠胆囊胆固醇结石形成

目的 探讨胆固醇结石的预防。方法 采用豚鼠为实验对象，随机分为三组，设置了空白组、对照组、预防组。结果 药物预防组较对照组成石率显著降低（P＜0．05），药物预防组胆汁中胆固醇含量较对照组显著降低（P＜0．05），胆汁酸含量较对照组显著升高（P＜0．05）。结论 绞股蓝能改善肝功能细胞，降低胆汁中胆固醇含量，提高胆汁酸含量，达到预防胆固醇结石形成的目的。