Gallstone prevention in prairie dogs: comparison of chow vs. semisynthetic diets

The effects of a standard rodent chow were compared with those of a semisynthetic diet of known composition (with and without added cholesterol) in the prairie dog model of cholesterol cholelithiasis. Gallstone incidence was 40% higher in animals fed a semisynthetic diet plus cholesterol compared to chow plus cholesterol. The semisynthetic diet plus cholesterol caused significant increases in tissue cholesterol levels (serum, liver and bile) and lithogenic index, but significant decreases in the activity of hepatic 3-hydroxy-3-methyl-glutaryl coenzyme A reductase and cholesterol 7 alpha-hydroxylase compared to chow plus cholesterol. Histologic study of liver sections revealed that the semisynthetic diet plus cholesterol resulted in moderate to marked portal tract changes characterized by bile duct proliferation, inflammatory infiltration and fibrosis, whereas the cholesterol-supplemented chow diet caused only slight bile duct proliferation with minimal inflammation and fibrosis in the portal areas. Dietary hyodeoxycholic acid prevented cholesterol gallstones and biliary cholesterol crystals when added to either chow plus cholesterol or semisynthetic plus cholesterol diets. The hyodeoxycholic acid supplements also prevented the development of severe histopathologic alterations along the portal tracts. Biliary cholesterol levels were elevated in prairie dogs fed cholesterol plus hyodeoxycholic acid; these animals had liquid crystals in the bile, and hyodeoxycholic acid and its 6 beta-isomer became the major biliary bile acids. A semisynthetic diet plus cholesterol is superior to a high cholesterol chow diet for gallstone formation and prevention studies, but in prolonged feeding experiments, the potential hepatotoxicity of this diet in the prairie dog must be appreciated.

[Ultrasonic scanning of the bile ducts in preventive examinations]

The results of the first experience in the use of ultrasonic investigation for primary diagnosis of some diseases of the gall bladder during mass screenings are analysed. Of 900 workers engaged in a factory diseases of the gall bladder (chronic cholecystitis, calculi and polyps of the gall bladder) were diagnosed in 171 (19%), of them in 15.5% the disease was first diagnosed, of these 8.7% without clinical signs. The method of ultrasonic investigation of the hepatoduodenal zone was discussed. A sonographic picture and the most typical sonographic signs of some diseases of the gall bladder were described.

Effect of lactulose on biliary lipid composition

It has been reported that lactulose can reduce biliary secondary bile acid (deoxycholate) composition and by this action can decrease biliary cholesterol saturation in patients with supersaturated bile. We tried to confirm this by feeding 60 g of lactulose per day during a period of 12 weeks to 8 healthy females with colonic adenomatous polyps and slightly elevated biliary cholesterol saturation. Although a 38% reduction of biliary deoxycholate was noted--38% after 4 weeks, and 32% after 12 weeks of lactulose feeding (P less than 0.01)--at the expense of a rise in both primary bile acids, cholate and chenodeoxycholate, no significant change in biliary cholesterol saturation was found after 4 nor after 12 weeks of lactulose feeding. These results do not support the concept that colonic bacterial metabolites of bile acids play a major role in the production of supersaturated bile and cholesterol gallstone formation.

Prophylactic cholecystectomy during splenectomy for beta thalassemia homozygous in Greece

The impact of prophylactic cholecystectomy upon early mortality and morbidity of splenectomy for patients with beta TH H was investigated. The results of our study suggested that it is a safe procedure that is not associated with any increase in operative mortality and postoperative complications. This was true even when beta TH H was complicated by pigment cirrhosis and ascites. In view of increasing longevity of those patients with beta TH H, as well as the increased risk for gallstones even after splenectomy, we recommend the use of prophylactic cholecystectomy as a standard approach for all patients undergoing splenectomy for beta thalassemia homozygous.

Hyodeoxycholic acid: a new approach to gallstone prevention

Hyodeoxycholic acid and its isomer, 6 beta-hyodeoxycholic acid, when added to a lithogenic diet prevented the formation of cholesterol gallstones and crystals in prairie dogs. This beneficial effect occurred in the presence of bile supersaturated with cholesterol. Hyodeoxycholic acid abolished the feedback inhibition of hepatic hydroxymethylglutaryl coenzyme A reductase activity, the rate-limiting enzyme of cholesterol synthesis, and prevented elevations in serum and liver cholesterol observed in animals fed a 0.4 percent cholesterol diet. The gallbladder bile of the animals fed hyodeoxycholic acid and 6 beta-hyodeoxycholic acid contained abundant liquid crystals. This suggests that these bile acids prevented the transition of cholesterol from its liquid crystalline phase to solid crystals and stones.

Simplification of cryoprecipitate coagulum choledocholithotomy by deletion of thrombin. Prevention of retained biliary duct stones

Conventional removal of stones from the biliary ducts can be difficult and may result in retained stones. We developed a modified tenacious coagulum that entraps biliary duct stones, resulting in a more complete extraction. Coagulum choledocholithotomy was simplified by mixing 20 parts of cryoprecipitate with one part of 10% calcium chloride solution without thrombin. Tenacious coagula were generated that had a tensile strength of 106 to 140 g/sq cm within three to six minutes and were 106% to 300% stronger than coagula with thrombin. This technique was performed on six patients. In each case, an intact coagulum that entrapped more calculi than were seen on the cholangiogram was extracted. This modified technique is simple, safe, nontraumatic, and achieves a more complete extraction of stones.

[Lithogenicity of bile in patients after ileal resection]

Biliary lipid composition and lithogenicity were studied in 40 patients after ileal resection of different extent. The lithogenic index increased in extended ileal resection and ileostomy groups. There was a significant positive correlation between the lithogenic index and the length of ileal resection (r = 0.65, p less than 0.001). Total bile acid concentration and the proportion of deoxycholic acid were decreased after ileal resections as compared to controls. Especially these changes were remarkable in the extended ileal resection and ileostomy groups (p less than 0.001). Nine out of 40 patients were restudied after one month of oral ursodeoxycholic acid administration (300mg/day). Ursodeoxycholic acid consistently reduced the lithogenicity by decreasing the proportion of cholesterol in bile. Ursodeoxycholic acid was useful reducing bile lithogenicity in patients whose bile was supersaturated after ileal resection.

[Wheat bran-type roughage reduces the lithogenicity of bile]

The effect of 30 g wheat bran on the lithogenic potency of bile was studied in ten healthy males (age 25.5 +/- 0.76 years; height 182.9 +/- 2.1 cm, weight 76.8 +/- 2.3 kg). Wheat bran was taken for over six weeks, at 15 g twice daily. Bile fluid was sucked out from the prepapilla after bile stimulation. Contraction of the gallbladder was checked by ultrasound. Concentration of total bile acids and bile acid spectrum, as well as the concentration of phospholipids, remained unchanged for the six weeks of increased wheat bran intake. Cholesterol concentration in bile decreased from 3.27 +/- 0.89 mmol/l to 2.50 +/- 0.67 mmol/l. The lithogenic index fell from 1.01 +/- 0.14 to 0.67 +/- 0.11. Concentrations and composition of lipids and lipoproteins in serum remained unchanged. An increased intake of wheat bran was thus shown to be a decisive dietary measure in the prevention and treatment of cholesterol gallstones.

Effects of bile acid oxazolines on gallstone formation in prairie dogs

The effects of 2 bile acid analogs, chenodeoxy-oxazoline [2-(3 alpha, 7 alpha-dihydroxy-24-nor-5 beta-cholanyl)-4,4-dimethyl-2-oxazoline] and ursodeoxy-oxazoline [2-(3 alpha, 7 beta-dihydroxy-24-nor-5 beta-cholanyl)-4,4-dimethyl-2-oxazoline] were examined in the prairie dog model of cholesterol cholelithiasis. Gallstones and biliary cholesterol crystals were induced in 5 out of 6 male prairie dogs fed a semisynthetic diet containing 0.4% cholesterol for 8 weeks. Six animals maintained on a low cholesterol control diet (0.08% cholesterol) exhibited neither gallstones nor biliary cholesterol crystals. The addition of 0.06% chenodeoxy-oxazoline to the lithogenic diet did not prevent induced cholelithiasis or the appearance of cholesterol crystals in bile. In contrast, 0.06% dietary ursodeoxy-oxazoline prevented gallstones in 5 out of 6 prairie dogs (but cholesterol crystals were present in the bile of 4 of these animals). Histologically, most of the livers from the prairie dogs fed the cholesterol-supplemented semisynthetic diet showed bile duct proliferation, inflammatory infiltration and fibrosis along the portal tracts. These pathologic changes were generally not ameliorated by adding chenodeoxy-oxazoline or chenodeoxy-oxazoline plus chenodeoxycholic acid to the diet. Portal tract pathology was markedly reduced in most animals by adding ursodeoxy-oxazoline to the cholesterol-supplemented diet. The pathologic changes overall could best be correlated with the presence of gallstones, but not with the incidence of biliary cholesterol crystals.

Prevention of cholesterol-induced gallstones by hyodeoxycholic acid in the prairie dog

Prairie dogs of both sexes were fed a semisynthetic diet containing 0.35% cholesterol for a period of 8 weeks. This lithogenic diet induced cholesterol gallstones in ten "lithogenic control animals", five males and five females. Three animals maintained with a high glucose, fat-free diet did not develop gallstones although the cholesterol saturation of their bile approached unity. The formation of gallstones was prevented in four out of five males and all five females fed the lithogenic diet plus 0.1% hyodeoxycholic acid (30 mg per kg body weight per day). The biles of the prairie dogs receiving hyodeoxycholic acid were abnormally colored, cloudy, and highly saturated with cholesterol but contained neither cholesterol crystals nor gallstones (with the exception of one male). Feeding the relatively hydrophilic bile acid, hyodeoxycholic acid, was associated with an increase in hepatic microsomal HMG-CoA reductase activity. Cholesterol 7 alpha-hydroxylase, on the other hand, was inhibited by the administered bile acid. The dietary hyodeoxycholic acid was transformed, in part, to 3 alpha, 6 beta-dihydroxy-5-beta-cholanoic acid and hyocholic acid. It is concluded that hyodeoxycholic acid and its metabolites did not prevent the induced cholelithiasis by causing a decrease in the concentration of biliary cholesterol. Instead, this hydrophilic bile acid apparently increases the amount of cholesterol in the bile, probably in the form of a liquid crystalline mesophase. Hyodeoxycholic acid apparently prevents gallstones by preventing the nucleation and aggregation of cholesterol crystals. The lithogenic diet induced moderate to marked bile duct proliferation together with portal fibrosis and inflammatory infiltration. The addition of hyodeoxycholic acid to the lithogenic diet reduced all of the portal tract changes.

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. There was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).

Effects of chenodeoxycholic and ursodeoxycholic acids on lipid metabolism and gallstone formation in the prairie dog

The prevention of cholesterol cholelithiasis by dietary chenodeoxycholic and ursodeoxycholic acids was studied in the male prairie dog (Cynomys ludovicianus). Gallstones were induced by administration of a semisynthetic diet containing 0.4% cholesterol for a period of 8 weeks. Groups of 5 or 6 animals received the lithogenic diet with added chenodeoxycholic or ursodeoxycholic acid (0.03% "low dose" or 0.06% "high dose"). Under the conditions used, the incidence of gallstones was reduced with the high dose of chenodeoxycholic acid and the low dose of ursodeoxycholic acid, but cholesterol crystals were detected in the biles of 20 of the 22 animals fed these bile acids. A control group maintained on a low (0.08%) cholesterol semisynthetic diet exhibited neither crystals nor stones and was the only group with a lithogenic index below 1.0. The administered bile acids tended to reduce the accumulation of cholesterol in liver and plasma. The activity of hepatic HMG-CoA reductase was significantly inhibited with all cholesterol-supplemented diets. Cholesterol 7 alpha-hydroxylase activity was elevated 83% in prairie dogs fed 0.4% cholesterol, but tended to return to normal levels when bile acids were added to this diet. Histologically, the livers of all animals on the semisynthetic (cholesterol-supplemented) diet exhibited bile duct proliferation, as well as portal fibrosis and inflammatory infiltration. These morphologic alterations were ameliorated by low dose supplementation with either chenodeoxycholic or ursodeoxycholic acid, but high dose bile acid supplementation failed to reduce these pathologic changes.

Influence of DL-2-phenyl[6-ethoxybenzothiazolyl-(2)-thio]propionic acid (EMD 34853) on gallstone formation in hamsters

The effects of two levels (50 and 167 mg/kg) of a new hypocholesterolemic drug (EMD 34853) on gallstone formation in hamsters were investigated. Lithogenicity was inhibited by 28-45%. Levels of biliary lipids (cholesterol, phospholipid, bile acids) were reduced in the drug-treated animals.

Moderate alcohol intake reduces bile cholesterol saturation and raises HDL cholesterol

The effect of alcohol on plasma high-density lipoprotein (HDL) cholesterol and on bile cholesterol saturation was measured in 12 healthy volunteers with a very low initial alcohol intake who drank 39 g alcohol daily for six weeks, and then abstained from alcohol for 6 weeks. HDL cholesterol (mean +/- SEM) rose significantly from 1.07 +/- 0.05 to 1.25 +/- 0.08 mmol/l (41.4 +/- 1.9 to 48.3 +/- 3.1 mg/dl) when alcohol was being consumed and fell to 1.04 +/- 0.06 mmol/l (40.2 +/- 2.3 mg/dl) during abstention. Bile cholesterol saturation index fell from 1.31 +/- 0.06 to 1.08 +/- 0.06 during the period of alcohol consumption and rose to 1.27 +/- 0.09 during abstention. There was a significant inverse correlation between bile saturation index and HDL cholesterol (r = -0.56). These data provide further evidence of a biochemical link between cardiovascular disease and cholesterol gallstones and suggest that moderate alcohol intake has some protective effect against both diseases.

[Recurrence and prevention of recurrence after dissolution of gallbladder lithiasis by chenodeoxycholic acid in 22 patients]

Dissolution of gallstones was observed 33 times in 22 patients. For 11 of them a recurrent lithiasis was dissolved by means of a second or third medical treatment. 21 patients have been followed for 3 to 6 years (median over 4 years). Without longstanding treatment the recurrence rate was 50 p. 100 in 3 years and 87.5 p. 100 in 6 years. Most of the patients should have relapsed in less than 9 years. Recurrences were always successfully treated with the same treatment but relapsed if the treatment was stopped (21 recurrences in 14 patients). A-1 month every 4 months-long standing treatment did not prevent recurrences in 8 patients whereas treatment every other month prevented recurrences in 5. It is therefore suggested to give long treatment after dissolution of gallstones to avoid recurrences. Its duration should be undefinite. Alternatives might include: 1) repeated dissolving treatments in case of recurrences, if relapses occur lately; 2) or longstanding treatment in case of early recurrences.

Influence of beclobrate on gallstone formation in hamsters

Three groups of male Syrian hamsters were fed a lithogenic diet (L), L plus 0.04% ethyl-2-[4-(p-chlorophenyl) methylphenoxy]-2-methylbutyrate (beclobrate); or L plus 0.17% beclobrate. After 60 days, the percentage of hamsters with gallstones on the three diets was 28, 16 and 12, respectively. Biliary phospholipid was not affected, but biliary cholesterol and bile acid were reduced significantly in both test groups.