Ground squirrel model for cholelithiasis: role of epithelial glycoproteins

The cholesterol-fed Richardson's ground squirrel (Spermophilus richardsonii) has proven to be an effective animal model in which to study factors that influence cholesterol gallstone formation and associated alterations in the gallbladder epithelium. Ground squirrels of either sex, fed a 2% cholesterol-enriched diet, exhibit cholesterol monohydrate crystal precipitation within 24 hours and macroscopically visible cholesterol stones by 3 weeks. Data on bile chemistry, biliary cholesterol precipitation, and various mucosal alterations occurring prior to, during, and after stone formation were collected using sampling intervals from 6 hours to 20 weeks on the diet. The results indicate that mucin hypersecretion appears to be more closely related to the initiation of nucleation than does either bile calcium of pH. Mucus hypersecretion begins within 18 hours of diet initiation and continues throughout the 20 week experimental period. Apical excrescences became more common and were larger in size during the early stages of cholelithiasis. Administration of aspirin during the experimental period demonstrated an inhibition of mucin synthesis and release. Gallstones were not formed in these aspirin-treated animals. A lectin-binding panel for 10 epithelial glycoprotein-related sugars indicated the mucin secreted by the gallbladder epithelium of 7 day experimental animals differed from that of controls. The most obvious difference was the abolition of WGA binding in the experimental animals, suggesting an absence of sialic acid expression in the mucin during the lithogenic process. Ultrastructural histochemistry indicated that both sulphomucin and sialomucin were present in the secretory granules and within the surface mucus layer of both experimental and control animals. Experimental animals, however, exhibited a significant predominance for sulphomucin. This pattern varies from that typically seen in other regions of the gastrointestinal tract where sialomucins predominate during pathologic processes.

Exercise and gall bladder function

Epidemiological research has demonstrated protective effects of varying strength from physical activity against the risk for several chronic diseases such as coronary heart disease, hypertension, non-insulin-dependent diabetes mellitus and osteoporosis. Epidemiological studies have been supported by experimental research showing that exercise training improves coronary heart disease risk factors and other health-related factors. In contrast, the association between physical activity, exercise and gall stone disease has not yet been firmly established. This paper presents the theoretical role of aerobic exercise: (i) in the primary prevention of gall stone disease; and (ii) as a potential prokinetic agent in high risk gall stone disease groups. Primary risk factors in the pathogenesis of gall stone formation include cholesterol supersaturation in the solutes that precipitate from bile, hypernucleation (measured as "crystal appearance time') and finally hypomotility of the gall bladder which allows bile stasis and crystal formation. While the results of epidemiological studies suggest that physical activity may be inversely associated with gall stone disease, the mechanisms by which exercise may influence gall stone disease pathogeneses are poorly understood. In this paper the association between physical activity and exercise to gall bladder function and gall stone disease will be examined. Recommendations for future research and the implications for the primary prevention of gall stone disease will also be discussed.

[A new theoretical and experimental validation of the treatment and prevention of cholelithiasis]

Approaches are proposed, new in principle, toward breaking biliary calculi into pieces, as well as toward prophylaxis of cholelithiasis. Exposure of the concrements to ultrasound with varying resonance frequency in a contact medium containing litholytic substances permits bringing about their reduction to fragments being safe for their evacuation from the biliary system. Prevention of cholelithiasis involves identification of precalculous period and exposure of the gallbladder region to vibration along with adopting conventional therapy.

Reduced cholesterol absorption in hamsters by crilvastatin, a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor

Crilvastatin, a new drug from the pyrrolidone family, has been previously shown to inhibit the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, in vitro and in vivo, to reduce the absorption of dietary cholesterol and to stimulate the activity of cholesterol 7 alpha-hydroxylase in the rat. The aim of this study was to evaluate the effects of crilvastatin on cholesterol and bile acid metabolism in the hamster. In hamsters fed on a lithogenic diet for 8 weeks, crilvastatin treatment (200 mg/day per kg body weight) did not change plasma lipid levels, failed to improve bile parameters and did not prevent gallstone formation. In hamsters fed on a basal cholesterol-rich (0.2%) diet for 8 weeks, crilvastatin at the same dose reduced the cholesterol level in the plasma by 20%, with a decrease of both low-density and high-density lipoprotein cholesterol. The drug did not significantly stimulate the biliary secretion of bile acids but significantly decreased the activity of acyl coenzyme A:cholesterol acyltransferase in the small intestine by 64%. This effect was enhanced when cholestyramine, a bile acid-sequestering resin, was given in combination with crilvastatin. Crilvastatin alone did not change the activity of cholesterol 7 alpha-hydroxylase in the liver, despite the marked reduction in both hepatic cholesterogenesis and intestinal absorption of dietary cholesterol (the absorption coefficient was 44 +/- 2% in treated hamsters vs. 61 +/- 7% in controls).

Differences in diet and food habits between patients with gallstones and controls

OBJECTIVE

To compare the food, energy, macronutrient and micronutrient intake of patients with gallstones to those of a control group of similar demographic characteristics.

DESIGN

Patient-control study.

SUBJECTS

54 gallstone patients and 46 control subjects.

METHODS

Two 24-hour dietary recalls and a "food frequency intake" questionnaire were obtained from patients and controls. In both groups, the presence/absence of gallstones was confirmed by ultrasonography. Participants answered a questionnaire on their physical activity patterns.

RESULTS

Gallstone patients consumed less food per day (g/day) and less fish and fruits than did control subjects. They also showed greater intakes of cereals, oils, sugars and meats than did control subjects and ate fewer meals per day, tending to omit evening snacks and more substantial evening meals. Further, patients spent less time walking and slept more than did control subjects. They also experienced fluctuations in body weight with greater frequency. Patients consumed more total calories (energy) and fats (especially monounsaturated fatty acids and saturated fatty acids), and less fiber, folate and magnesium than did control subjects. Women with gallstones were shown to have significantly higher intakes of total fats, monounsaturated fatty acids, saturated fatty acids and cholesterol, and significantly lower intakes of fiber, folate, magnesium, calcium and vitamin C than control women. For all vitamins and minerals studied, patients showed a greater percentage of intakes below those recommended.

CONCLUSIONS

Dietary intervention might provide a method of avoiding the recurrence of gallstones as well as a method of prevention control subjects.

[Galvanization of the liver in the prevention of cholelithiasis in patients with chronic cholecystitis]

It is shown in 22 patients with chronic noncalculous cholecystitis that hepatic exposure of such patients to constant current changes chemical composition of bile components in such a way that bile lithogenic characteristics make formation of choleliths less probable.

Effect of lactulose and fiber-rich diets on bile in relation to gallstone disease: an update

The primum movens in cholesterol gallstone formation is hepatic cholesterol hypersecretion and chronic supersaturation of bile. From this event a cascade of contributing factors can be differentiated: (i) Motility defects with impaired gallbladder contractility and gallbladder stasis, but also with small and large intestinal hypomotility. (ii) Multiple biochemical defects in gallbladder bile with increased biliary proteins, increased deoxycholic acid and rapid crystallization of biliary cholesterol from supersaturated unstable vesicles. There is considerable evidence that slow intestinal and colonic transit can increase the deoxycholic acid pool size and biliary cholesterol saturation. Changes in intestinal transit influence the anaerobic bacterial enzymatic biotransformation of conjugated cholate to more hydrophobic deoxycholate. This leads to biliary cholesterol hypersecretion and gallstone formation. Prokinetic drugs or administration of lactulose or fiber products like bran can change the slow intestinal transit favourably with subsequent reduction in deoxycholic acid formation and cholesterol saturation of bile. Whether these applications are indeed of value in the long-term prevention of gallstone disease, however, is doubtful, since fiber-rich diet in prevention of gallstone recurrence after complete gallstone dissolution was not successful.

Cholecystokinin increases bile acid synthesis with total parenteral nutrition but does not prevent stone formation

Total parenteral nutrition (TPN) is associated with cholestasis and gallstones. Gallbladder stasis may be important in the development of gallstones, and cholecystokinin (CCK) to stimulate gallbladder contraction has been proposed as a treatment to prevent this complication. We studied in vivo bile acid synthesis and bile acid output in miniswine on TPN to test whether daily CCK improves bile acid output and normalizes bile acid profiles with TPN. Nine miniswine were nutritionally maintained with TPN for 4 weeks; four pigs received CCK (0.1 mg/kg) iv daily. In vivo bile acid synthesis was measured with injection of 7 alpha-tritiated cholesterol. An increase in tritiated water reflects the activity of 7 alpha-hydroxylation, the rate-limiting step in bile acid synthesis. At the end of 4 weeks, bile was collected and bile acid output and bile salt profiles were determined. One of five animals on TPN developed gallstones while two of four receiving daily CCK developed stones. In vivo bile acid synthesis decreased with TPN (controls, 63 +/- 9 mg/24 hr versus TPN, 13 +/- 4 mg/24 hr) and increased in TPN animals with CCK treatment (TPN-CCK, 105 +/- 35 mg/24 hr). Bile acid profiles are changed with TPN with more secondary bile acids, this was not improved with CCK. CCK improved bile acid synthesis and bile acid output but failed to prevent gallstone formation or normalize bile salt profiles. In addition to promoting gallbladder contraction, CCK may have a stimulatory effect on bile acid synthesis. CCK alone did not prevent gallstone formation.

Gallbladder contraction induced by intravenous erythromycin administration. Relation to body mass index

BACKGROUND/AIMS

To study the action of intravenously administered erythromycin lactobionate on human gallbladder volume, as a possible preventive method against gallbladder stone formation, in high risk patients such as those in sepsis, long standing fasting periods or those receiving prolonged total parenteral nutrition or octreotide.

MATERIALS AND METHODS

Twenty-two volunteers randomized to receive intravenously either erythromycin lactobionate 7 mg per kg (study group) or normal saline (controls). We measured ultrasonographically the gallbladder volume before and at 5, 15, 35, 55, 90, 120 and 180 min after the infusion.

RESULTS

Erythromycin induced a biphasic gallbladder contraction, with maximum contractility at 15 min (10.2%) and between 120 and 180 min (22.6%), compared to normal saline controls. Late contractility was correlated to body mass index (BMI).

CONCLUSIONS

Erythromycin activity on gallbladder contraction is proved. Its biphasic action needs further investigation to find the involved mechanism(s). Long term administration is also necessary to test its efficacy in preventing gallbladder dilatation.

A novel 5-lipoxygenase inhibitor prevents gallstone formation in a lithogenic prairie dog model

Gallstone formation is dependent on biliary cholesterol supersaturation, the pronucleating effects of gallbladder mucin, and inflammation. We evaluated the effect of aspirin (ASA) and a 5-Lipoxygenase inhibitor (FLAPI) on cholesterol precipitation and leukotriene levels in an animal model of cholesterol gallstone formation. Male prairie dogs were divided into four dietary groups: normal chow controls, 1.2 per cent cholesterol (XOL), 1.2 per cent cholesterol plus ASA (XOL + ASA, 100 mg/kg/d), and cholesterol plus FLAPI (XOL + FLAPI, 100 mg/kg/12h). At 3 weeks the subjects were anesthetized, cholecystectomy performed, and the common duct cannulated for bile sampling. Cholesterol precipitation, lithogenic indices, and leukotriene content were analyzed. The group XOL + FLAPI did not form cholesterol crystals, whereas the group XOL + ASA did (P < 0.05, Fisher's exact test). All cholesterol-fed groups had significantly increased lithogenic indices when compared to controls. The XOL + FLAPI group showed a significant and paradoxical increase in LTB4 compared to the other groups (P < 0.05, ANOVA, Fisher's PLSD). This study has shown a significant decrease in the rate of cholesterol stone formation through the use of a novel leukotriene inhibitor at high doses, despite a high cholesterol diet.

Prevention of cholesterol cholelithiasis by dietary unsaturated fats in hormone-treated female hamsters

We examined the effect of diet on gallstone incidence and the composition of biliary phosphatidylcholines in methyltestosterone-treated female hamsters. These hamsters were fed a nutritionally adequate purified lithogenic diet containing 2% corn oil, 4% butterfat, 0.3% cholesterol, and 0.05% methyltestosterone, resulting in a cholesterol gallstone incidence of 86%. This incidence was lowered when mono- and polyunsaturated fats or fatty acids were added to the diet: 2.5% oleic acid resulted in total prevention of cholesterol cholelithiasis, 2.5% linoleic acid, and 4% safflower oil (78% linoleic acid content) reduced gallstone incidence to 26 and 8%, respectively. An additional 4% butterfat (29% oleic acid content) produced gallstones in 50% of the animals. At the end of the 6-wk feeding period, the bile of all hamsters was supersaturated with cholesterol. The major biliary phosphatidylcholine species in all groups were (sn-1-sn-2): 16:0-18:2, 16:0-18:1, 18:0-18:2, 16:0-20:4, and 18:2-18:2. The safflower oil- and linoleic acid-fed hamsters exhibited an enrichment of 16:0-18:2 (16-18%); added butterfat or oleic acid increased the proportion of 16:0-18:1 (9 and 25%, respectively). We conclude that the phosphatidylcholine molecular species in female hamster bile can be altered by dietary fats/fatty acids and that mono- and polyunsaturated fatty acids play a role in suppressing the induced cholelithiasis.

The role of prophylactic cholecystectomy in the short-bowel syndrome

OBJECTIVES

To determine the factors associated with cholelithiasis and define the role of prophylactic cholecystectomy in the short-bowel syndrome.

DESIGN

Retrospective clinical review of cohort of consecutive patients.

SETTING

Tertiary care, academic medical center.

PATIENTS

Fifty adult (age, > 16 years) patients with intestinal remnants less than 180 cm were evaluated over a 15-year period.

MAIN OUTCOME MEASURES

Incidence and natural history of cholelithiasis, postoperative morbidity, and mortality rates.

RESULTS

Prophylactic cholecystectomy was performed in 5 patients (10%). Ten patients (20%) died within 20 days without evidence of gallstones. Eleven (31%) of the other 35 patients at risk developed biliary disease; 6 of these patients had inflammatory complications or common bile duct stones. Biliary disease was more likely (P < .05) in patients with intestinal remnant length less than 120 cm (47% vs 13%), an absent ileocecal junction (41% vs 0%), long-term total parenteral nutrition (45% vs 13%), and Crohn's disease (67% vs 24%). Patients with mesenteric vascular disease had high initial mortality (50%) and a 38% incidence of biliary disease. Patients with cancer and/or irradiation had a lower initial mortality (7%) and no biliary disease. Patients with benign conditions had a significant incidence of cholelithiasis (57%).

CONCLUSIONS

Patients with the short-bowel syndrome have a significant risk for cholelithiasis if the intestinal remnant length is less than 120 cm, total parenteral nutrition is required, and the terminal ileum is resected. Prophylactic cholecystectomy is indicated in patients with benign conditions and anticipated long-term survival. It should also be considered in patients with mesenteric vascular disease who, despite significantly shortened survival, may have a high incidence of early biliary problems.

IV chenodeoxycholate prevents calcium bilirubinate gallstones during total parenteral nutrition in the prairie dog

BACKGROUND

The purpose of this study was to determine whether IV chenodeoxycholate (CDC) could prevent total parenteral nutrition (TPN)-associated pigmented gallstones in the prairie dog.

METHODS

Twelve prairie dogs were divided into two equal groups, each receiving an identical TPN regimen. Each animal received 92 kcal/d with 61% of the calories from carbohydrate. The total volume of infusate delivered to each animal was 59 mL/d. Animals in one group, termed the TPN + CDC group, received a daily bolus injection of CDC at a dose of 15 mg/kg. Prairie dogs in the second group, termed the TPN group, received water (vehicle carrier) 1 mL/kg/d. The TPN and TPN + CDC groups received TPN for 40.3 +/- 1.3 and 42.5 +/- 0.6 days, respectively.

RESULTS

There was no statistical difference in the initial and final weights between the two groups. None of the TPN + CDC-treated animals had gallstones or calcium bilirubinate crystals. In contrast, all of the TPN-treated animals had calcium bilirubinate crystals (p = .002), and five of six had macroscopic black pigmented gallstones (p = .015). Cholesterol crystals were not observed in either group of animals. The amount of biliary bilirubin and ionized calcium was significantly greater in the TPN group (both p < .001); however, both groups had a similar total biliary calcium concentration.

CONCLUSION

IV CDC is effective in preventing TPN-associated gallstones in the prairie dog.

Methionine, but not taurine, protects against formation of canine pigment gallstones

Dogs fed a marginal protein, high carbohydrate diet containing borderline amounts of methionine consistently develop pigment gallstones, marked taurine deficiency, and abnormal secretion of unconjugated bile salts. Since taurine is essential for normal secretion of bile salts in the dog, a species that cannot use glycine for bile salt conjugation, we hypothesized that taurine deficiency plays an important role in the pathogenesis of canine pigment gallstones. The rates of formation of pigment gallstones at 6 weeks were compared in dogs fed normal dog chow, lithogenic diet alone, and lithogenic diet supplemented with either taurine or methionine (45-55 mg/kg/day). No dog fed normal dog chow, but 11 of 12 dogs fed lithogenic diet, formed pigment gallstones and sludge. Supplementation of the lithogenic diet with taurine did not protect against pigment gallstones; five of six dogs developed gallstones and sludge. However, supplementation with methionine was protective, only one of six dogs was found to have a few flecks of pigmented material in its gallbladder. Interestingly, neither taurine nor methionine protected against previously observed increases in the concentrations of biliary calcium and bile salt profile indicating that at least some of the abnormalities previously observed in this model are not related to methionine/taurine deficiency. These results disprove our initial hypothesis that taurine deficiency plays an important role in the pathogenesis of pigment gallstones, but did show that a lack of methionine is linked to the formation and growth of canine pigment gallstones. The mechanism(s) leading to the formation of gallstones in dogs that are methionine deficient are is not clear from these studies.

Different protective effects of tauroursodeoxycholate, ursodeoxycholate, and 23-methyl-ursodeoxycholate against taurolithocholate-induced cholestasis

The coinfusion of tauroursodeoxycholate (TUDC) prevents taurolithocholate (TLC) -induced cholestasis. 23-Methyl-ursodeoxycholate (MUDC) is a side-chain derivative of ursodeoxycholate (UDC). If conjugation with taurine is important for the protective effect of UDC, the MUDC may not be as able as TUDC to prevent TLC-induced cholestasis since it is poorly amidated by the liver. To answer this question, isolated livers of adult Sprague-Dawley rats were coinfused with MUDC (UDC, TUDC) and TLC. After 15 min, inflow rates of the bile acids were doubled. In further experiments taurine in excess was added to the coinfused bile acids. The uptake of bile acids was >90% in all groups, irrespective of whether they were perfused alone or in combination. Single perfusion of TLC caused a rapid decrease in bile flow. UDC and MUDC were hypercholeretic; TUDC moderately choleretic. During coinfusion experiments, TUDC not only completely abolished cholestasis but in addition increased bile flow and biliary bile acid secretion. UDC did prevent TLC cholestasis at the lower inflow rates. At high inflow rates, bile flow decreased significantly. Addition of taurine to this bile acid combination did not significantly improve the anticholestatic effect of UDC. At low and high infusion rates of MUDC, cholestasis induced by TLC was reduced very little. Cumulative bile flow over 30 min fell by approximately 70% as compared to that of singly perfused MUDC. Addition of taurine to the coinfused MUDC/TLC slightly, but less significantly, improved the anticholestatic effect of MUDC. Since MUDC is by far less protective than UDC (and TUDC) despite similar physiochemical properties, it is concluded that taurine conjugation of UDC seems to be a prerequisite to prevent TLC-induced cholestasis. The results imply that treatment of cholestatic liver diseases with taurine-conjugated UDC might be more appropriate than with unconjugated UDC in cases where taurine conjugation is defective or where taurine depletion has occurred.

Effects of ursodiol or ibuprofen on contraction of gallbladder and bile among obese patients during weight loss

Rapid loss of weight in obese patients is associated with increased saturation of bile with cholesterol, increased nucleation and growth of cholesterol crystals, and gallstones. The aims of this study were to determine the effects of rapid weight loss on contraction of the gallbladder and to evaluate the effects of ursodiol and ibuprofen on saturation, nucleation and growth, and contraction. Forty-seven obese patients entering a very low calorie dietary program were randomized to receive ursodiol, 1200 mg/day, ibuprofen, 1600 mg/day, or placebo for 12 weeks. Contraction of the gallbladder to a liquid meal was evaluated by ultrasonography, and duodenal bile was collected initially and after six and 12 weeks. Diet caused reduced contraction of the gallbladder, increased cholesterol saturation, and increased nucleation and growth of crystals. Ursodiol reduced saturation and prevented increases in nucleation and growth and contraction. Ibuprofen prevented the increase in saturation and the reduction in contraction with a trend opposing the increase in nucleation and growth. In conclusion, during dieting, contractility of the gallbladder to meals is reduced. The effectiveness of ursodiol in preventing gallstones may be explained partially by effects on contraction. Ibuprofen deserves further study because of its effects on saturation, nucleation and growth, and contraction.

Gallstone recurrence after successful dissolution therapy

After successful dissolution therapy of cholesterol gallbladder stones bile again becomes supersaturated and recurrent gallstones may develop. Three different postdissolution treatments [500 mg ursodeoxycholic acid (UDCA) per day (N = 14, group I), 100 mg aspirin per day (N = 14, group II) and diet (N = 15, group III) versus a control group (no treatment, N = 15, group IV) aimed at preventing recurrence of gallstones were investigated in a prospective, randomized study in 58 gallstone patients (33 female, 25 male) after complete stone clearance. Bile samples (prior to dissolution therapy and at stone recurrence) were investigated for biliary cholesterol (C), phospholipids (PL), total bile acid concentration (BA), cholesterol saturation index (CSI), total lipid concentration (TLC), total biliary protein concentration (TP), and nucleation time (NT). In group IV multiple gallstones tended to recur more often than solitary stones (66.7% vs 16.7%) whereas in groups I-III only solitary stones recurred. Recurrent gallbladder stones were detectable in 10 patients (eight patients in group IV and one each in groups I and II, respectively) within one year after dissolution and in two patients (one each in groups III and IV, respectively) after 15 months. Furthermore, the probability of stone recurrence was significantly higher in untreated patients as compared to treated patients. In nine (group IV) of 12 patients with recurrent stones NT, C, CSI, PL, BA, TLC, TP, and bile acid spectrum remained nearly unchanged as compared to their pretreatment values, whereas in three (groups I-III) of 12 cases a decrease in C, CSI, and TP was observed during therapy. However, in each of these three patients, initial and after-treatment TP was significantly higher and NT shorter as compared to groups I-IV. Furthermore, in these cases (N = 3) NT was prolonged, whereas no significant changes were found in PL, BA, TLC, and bile acid spectrum. Recurrence of gallstones, which seems to occur more likely in patients with multiple stones as compared to solitary stones, will happen in the early stage after stone clearance, again causing biliary pain. UDCA, aspirin or diet will reduce the probability for recurrent stones after complete gallstone dissolution.

[Occupational-social influence in the course of cholelithiasis]

The aim of the study was to examine the relationship between the work load, evaluated by the occupational activity, and the incidence of cholelithiasis. In total 372 subjects (169 cholelithiasis patients examined using USG, and 203 controls), hospitalised in 1993 in the Department of Gastroenterology, Regional Hospital, Białystok, completed the questionnaire. Attention was also given to age, sex, permanent residence, education and physical activities after work. A moderate physical effort, both occupational and non-occupational, seemed to reduce the risk of cholelithasis.

Symptoms of gallstone disease in a Swedish population

OBJECTIVE

To assess the significance of symptoms of gallbladder stones.

DESIGN

A population-based screening study to identify patients with gallbladder stones and to investigate their symptoms. To compare these results with symptoms in gallstone-free individuals and in patients with clinically diagnosed gallbladder stones, in order to find out which symptoms are associated with gallbladder stones.

METHODS

Five hundred and fifty-six men and women, aged 40 and 60 years, were screened with ultrasonography to find subjects with gallbladder stones and those already cholecystectomized. One hundred clinically diagnosed gallstone patients were investigated for symptoms and compared to individuals in the survey.

RESULTS

There was no symptom that occurred significantly more frequently in patients with incidental gallbladder stones than in individuals without. Patients with clinically diagnosed gallstones suffered significantly more often from most of the symptoms that were assessed.

CONCLUSION

The majority of people with incidental gallbladder stones are asymptomatic. A large minority of gallstone-free individuals in the general population have abdominal symptoms. Combinations of different symptoms may increase their predictive value to a level with clinical utility.

Antilithiasic and hypocholesterolemic effects of diets containing autoclaved amylomaize starch in hamster

The prevention of cholelithiasis by dietary manipulation was investigated in hamsters receiving a fat-free lithogenic (L) diet or this diet in which sucrose was replaced by 12 (group AS12), 36 (group AS36), 48 (group AS48), or 72.5% (group AS72.5) of autoclaved amylomaize starch for seven weeks. All hamsters (6/6) had cholesterol gallstones in groups L and AS12, while only 3/6 hamsters in group AS36 had gallstones. None were present in groups AS48 and AS72.5. Except in group AS12, biliary cholesterol level and lithogenic index (LI) decreased significantly in hamsters receiving amylomaize starch. Plasma cholesterol concentration was reduced by 31 and 54%, respectively, in groups AS48 and AS72.5 as compared to group L. The concentration of esterified cholesterol in the liver was also reduced significantly in all groups receiving amylomaize starch. Hepatic cholesterogenesis was decreased by 74 and 65%, respectively, in groups AS48 and AS72.5 as compared to group L. The transformation of cholesterol to bile acids was increased in group AS72.5 (+152%) as compared to L, while fecal cholesterol excretion was strongly lowered (-31%). Amylomaize starch reduced the microbial transformation of cholesterol to coprosterol and epicoprosterol, and in group AS72.5 it decreased the degradation of cholic acid. Thus, this autoclaved amylomaize starch, which could be used in human nutrition, prevents cholelithiasis and lowers cholesterolemia.

A radical view of gallstone aetiogenesis

It is proposed that gallstones stem from insufficiency of micronutrient antioxidants relative to the load of oxidants and/or oxidation-prone substrates within hepatocytes in such a way that ancillary hepatobiliary resources, including bilirubin with lactoferrin and mucin, are mobilized to combat oxidative stress but inadvertently promote lithogenesis. Aberrant activities of hepatic cytochrome P450 mono-oxygenases and of haem oxygenase are integral to this template, because differential inhibition or activation of these enzymes would help to rationalize the spectrum of human gallstone composition and also the different outcomes when animals are fed the same lithogenic diets. The hypothesis is based on a decade of work on another lithogenic disease, chronic pancreatitis. It accommodates observations on human and experimental gallstones, it is testable and, as shown by studies of chronic pancreatitis, has implications for primary disease prevention.