Deoxycholic Acid Excretion Research Articles

Free Deoxycholic Acid Exacerbates Vascular Calcification in CKD through ER Stress-Mediated ATF4 Activation.

Our metabolome approach found that levels of circulating, free deoxycholic acid (DCA) is associated with the severity of vascular calcification in patients with CKD. However, it is not known whether DCA directly causes vascular calcification in CKD. Using various chemicals and animal and cell culture models, we investigated whether the modulation of DCA levels influences vascular calcification in CKD. CKD increased levels of DCA in mice and humans by decreasing urinary DCA excretion. Treatment of cultured VSMCs with DCA but no other bile acids (BAs) induced vascular calcification and osteogenic differentiation through endoplasmic reticulum (ER) stress-mediated activating transcription factor-4 (ATF4) activation. Treatment of mice with Farnesoid X receptor (FXR)-specific agonists selectively reduced levels of circulating cholic acid-derived BAs, such as DCA, protecting from CKD-dependent medial calcification and atherosclerotic calcification. Reciprocal FXR deficiency and DCA treatment induced vascular calcification by increasing levels of circulating DCA and activating the ER stress response. This study demonstrates that DCA plays a causative role in regulating CKD-dependent vascular diseases through ER stress-mediated ATF4 activation.

Black, pinto and white beans lower hepatic lipids in hamsters fed high fat diets by excretion of bile acids

Hypolipidemic and anti-obesity properties of extruded black, pinto and white beans were examined in male Syrian hamsters fed high fat diets for 3 weeks. The efficiency and effectiveness of extruder processing to eliminate heat-labile antinutrients were also determined. Hamsters fed a high fat diet containing 40% extruded black beans gained the same amount of weight as animals on a low-fat chow diet (based on AIN-93G). Total plasma cholesterol of the hamsters fed bean flour- based diets tended to be lower, ranging between 298 and 356 mg/dL, compared to 365 mg/dL for the control group and total and free liver cholesterol was about 50 and 33% lower, respectively, in the livers (freeze-dried) of hamsters fed the black turtle bean (BB) and pinto bean (PB) diets. The nitrogen content of the feces from hamsters fed the PB and white bean (WB) diets were 2.6x higher than the control and the excretion of deoxycholic acid (DCA) and lithocholic acid (LCA) was higher in all legume fed hamsters The results show that extrusion efficiently and economically reduces anti-nutritive factors that inhibit the digestion and absorption of proteins and carbohydrates.Graphical abstract

Long-Term β-galacto-oligosaccharides Supplementation Decreases the Development of Obesity and Insulin Resistance in Mice Fed a Western-Type Diet.

ScopeThe gut microbiota might critically modify metabolic disease development. Dietary fibers such as galacto‐oligosaccharides (GOS) presumably stimulate bacteria beneficial for metabolic health. This study assesses the impact of GOS on obesity, glucose, and lipid metabolism.Methods and resultsFollowing Western‐type diet feeding (C57BL/6 mice) with or without β‐GOS (7% w/w, 15 weeks), body composition, glucose and insulin tolerance, lipid profiles, fat kinetics and microbiota composition are analyzed. GOS reduces body weight gain (p < 0.01), accumulation of epididymal (p < 0.05), perirenal (p < 0.01) fat, and insulin resistance (p < 0.01). GOS‐fed mice have lower plasma cholesterol (p < 0.05), mainly within low‐density lipoproteins, lower intestinal fat absorption (p < 0.01), more fecal neutral sterol excretion (p < 0.05) and higher intestinal GLP‐1 expression (p < 0.01). Fecal bile acid excretion is lower (p < 0.01) in GOS‐fed mice with significant compositional differences, namely decreased cholic, α‐muricholic, and deoxycholic acid excretion, whereas hyodeoxycholic acid increased. Substantial changes in microbiota composition, conceivably beneficial for metabolic health, occurred upon GOS feeding.ConclusionGOS supplementation to a Western‐type diet improves body weight gain, dyslipidemia, and insulin sensitivity, supporting a therapeutic potential of GOS for individuals at risk of developing metabolic syndrome.

Determination of Secondary Bile Acids in the Mice Feces. Controversies on their Involvment in the Pathogenesis of Colorectal Cancer

Abstract Objectives: The aim of the study was to determine the level of secondary bile acids (SBA) in the diets and feces of mice and the variation of amount ingested/excreted if these SBA are administered as monotherapy or in 1:1 dose. Methods: The mice were divided into 4 groups and fed for 140 days with different diets. The control lot received a normal diet and the others received diets supplemented with 0.25% deoxycholic acid (DCA), 0.25% lithocholic acid (LCA) and 0.125% DCA+0.125% LCA. After 140 days, the mice feces were collected and homogenized to obtain a mixture for each lot from which the determinations of the studied SBA were performed. For the mice food evaluation, portions of 10 g from each of the 4 diets were subjected to the SBA determination. Results: The daily ingestion over more than 4 months of DCA or LCA added to the diet and administered as monotherapy determine a significantly increase of the SBA eliminated into the feces (the DCA level was 11x higher, and of the LCA 233x higher). If half of the LCA dose is replaced with DCA, the level of LCA in the feces gets comparable with that of the DCA (their combined amounts represents only 13x higher increase of these two bile acids in feces). Conclusions: The simultaneous ingestion and excretion of DCA and LCA can be considered as a particular situation ruled by endogenous mechanisms. This behavior represents an important observation, knowing that the bile acids effects in the colorectal cancer are dose dependent.

Effect of colesevelam on faecal bile acids and bowel functions in diarrhoea-predominant irritable bowel syndrome.

About one-third of patients with IBS-diarrhoea (irritable bowel syndrome-D) have evidence of increased bile acid synthesis or excretion. To assess effects of the bile acid sequestrant, colesevelam, on faecal excretion of BAs, hepatic BA synthesis and diarrhoea in IBS-D; to appraise whether individual or random stool samples accurately reflect 48-h total faecal bile acid excretion and proportions of the main bile acids excreted and to study the faecal fat excretion in response to colesevelam. A single-centre, unblinded, single-dose trial of effects of colesevelam, 1875mg [3 tablets (625mg tablets)] orally, twice daily, for 10days on total 48-h faecal bile acid excretion and fasting serum C4 (7α-hydroxy-4-cholesten-3-one; surrogate of hepatic bile acid synthesis). Stool diaries documented bowel functions for 8days prior and 8days during colesevelam treatment. Stool 48-h samples and fasting serum were collected for faecal fat, faecal bile acid and serum C4. Colesevelam was associated with significantly increased faecal total bile acid excretion and deoxycholic acid excretion, increased serum C4 and more solid stool consistency. There was a significant inverse correlation between number of bowel movements per week and the total bile acid sequestered into stool during the last 48h of treatment. Random stool samples did not accurately reflect 48-h total or individual faecal bile acid excretion. Sequestration of bile acids by colesevelam did not increase faecal fat. Colesevelam increases delivery of bile acids to stool while improving stool consistency, and increases hepatic bile acid synthesis, avoiding steatorrhoea in patients with IBS-D. Overall effects are consistent with luminal bile acid sequestration by colesevelam.

Amaranth Grain Brings Health Benefits to Young Normolipidemic Rats

This paper reports the impact of an extruded amaranth (Amaranthus spp) supplement on intestinal bile and fatty acids of normolipidemic rats. Forty-eight rats were fed either a control diet AIN 93-G (12 or 18% protein), or one of two levels of supplemental extruded amaranth flour for 48 days. Plasma glucose, insulin, total cholesterol, their fractions, and triacylglycerols, liver weight and lipid content, cecum short-chain fatty acids and fecal excretion of bile acids were determined. While no significant differences in the levels of plasma triacylglycerols, glucose or insulin, and liver parameters due to the diet were detected. Although amaranth promotes reduction of both total and LDL serum cholesterol, increased production of butyric acid in cecum and fecal excretion of deoxycholic acid in the feces. These results suggest that amaranth used routinely as a supplement to the standard casein diet could have a health-promoting value in the normal rat.

Docosahexaenoic acid-rich fish oil and pectin have a hypolipidemic effect, but pectin increases risk factor for colon cancer in rats

This study was designed to compare the effect of fish oil rich in DHA and pectin on the level of plasma lipids, hepatic HMG CoA reductase activity, microsomal membrane fluidity, colonic luminal content of short chain fatty acids (SCFA) and fecal excretion of bile acids and neutral sterols in rats. Male SD rats (7wks) were divided into three groups according to dietary fat sources, beef tallow (BT), corn oil (CO), fish oil (FO) and each group was subdivided into cellulose and pectin groups. The rats were fed for 25 wks the experimental diet containing 15% fat and 6% fiber and all rats were intramuscularly injected. with DMH. FO significantly reduced the levels of plasma Chol, TG, LDL-C, VLDL-C and hepatic HMG CoA reductase activity and increased membrane fluidity as compared with BT and CO. Pectin significantly reduced the levels of plasma Chol, VLDL-C and LDL-C, but increased HDL-C, HMG CoA reductase activity and membrane fluidity (p<0.05). However, pectin significantly increased the luminal content of butyrate and propionate in CO-fed rats and increased fecal excretion of deoxycholic acid and lithocholic acid in BT and CO-fed rats (p<0.05). Overall, fish oil had a protective effect against CVD by inhibiting hepatic HMG CoA reductase activity and increasing hepatic microsomal fluidity, thus leading to a reduction in plasma lipids. Pectin also had a protective effect against CVD by increasing fecal excretion of neutral sterols and hepatic microsomal fluidity. Pectin, however, increased risk factors for colon cancer by increasing the production of secondary bile acids and SCFA in the colon.

Dietary Stearic Acid Reduces Plasma and Hepatic Cholesterol Concentrations without Increasing Bile Acid Excretion in Cholesterol-Fed Hamsters1–4

Although there is general agreement that saturated fatty acids elevate plasma cholesterol concentrations, the relative effects of individual fatty acids on cholesterol and bile acid metabolism are less clear. In this study, cholesterol and bile acid responses to diets enriched in different saturated fatty acids were investigated in hamsters. The six diets examined were as follows: 5% fat (g/100 g) enriched in palmitic acid (16:0) with no cholesterol, 5% fat 16:0-enriched, 0.05% cholesterol (wt/wt), and four diets containing 0.05% cholesterol and 15% fat with each diet enriched in lauric (12:0), myristic (14:0), palmitic (16:0), or stearic acid (18:0). Total plasma cholesterol concentration was significantly greater in hamsters fed the 14:0-enriched diet relative to those fed the 18:0-enriched diet (P < 0.05). Both plasma and liver cholesterol concentrations of hamsters fed 18:0 did not differ from those of the group fed no dietary cholesterol. In all instances, differences in total plasma cholesterol were accounted for within the HDL fraction; no significant treatment differences in VLDL or LDL cholesterol were found. Total daily fecal bile acid excretion was higher in hamsters fed the 15% fat 16:0 diet compared with those fed no dietary cholesterol (P < 0.05), but not significantly different from other treatment groups. There was greater deoxycholic acid excretion (P < 0.05) from hamsters fed the 14:0 and 16:0 diets compared with those fed the 18:0-enriched diet. Small intestinal + gallbladder bile acids, an index of pool size, did not differ significantly among the groups. The observed relative hypocholesterolemic effect of stearic acid was not mediated by increased bile acid excretion.

Bile acid excretion and cholesterol 7 alpha-hydroxylase expression in hypercholesterolemia-resistant rabbits

We have developed a partially inbred substrain of New Zealand white rabbits (CRT/mlo) that are resistant to the hypercholesterolemia that accompanies cholesterol feeding to normal rabbits. The plasma cholesterol concentration of normal rabbits increases dramatically from about 30 mg/dl to > 300 mg/dl after they are fed a 0.1% cholesterol-enriched diet for 3-4 months. Cholesterol-fed CRT/mlo animals, however, maintain a cholesterol level of about 30 mg/dl during the entire cholesterol feeding period. In addition to the low plasma cholesterol level, measurements of cellular cholesterol indicate that the hepatic cholesterol content of the cholesterol-fed resistant rabbit remains markedly lower than it does in normal animals fed the same diet. The only mechanism for removal of significant quantities of cholesterol carbon from the body is via the fecal excretion of cholesterol, neutral sterol metabolites, and bile acids. In comparison to the basal, low-cholesterol diet, we observed that cholesterol-fed resistant rabbits had increased excretion of lithocholic acid, while excretion of this bile acid by cholesterol-fed normal rabbit remained similar to basal diet levels. Deoxycholic acid excretion, the other main bile acid excreted in the feces of rabbits, was decreased in response to cholesterol challenge in animals with either resistant or normal phenotypes, but the decrease was significantly less in the resistant rabbits. Thus, the resistant rabbits excreted relatively more lithocholic and deoxycholic acid than did the cholesterol-fed normal rabbit. The difference in bile acid excretion was also manifest by a higher than normal level of cholesterol 7 alpha-hydroxylase activity and cholesterol 7 alpha-hydroxylase mRNA in the livers from resistant versus normal rabbits. As cholesterol 7 alpha-hydroxylase is the putative rate-limiting step of bile acid synthesis, we believe that the increased excretion of bile acids by resistant animals is due, at least in part, to increased levels of cholesterol 7 alpha-hydroxylase expression.

Differential effects of ursodeoxycholic acid and ursocholic acid on the formation of biliary cholesterol crystals in mice

The preventive effect of 3 alpha, 7 beta, 12 alpha-trihydroxy-5 beta-cholanoic acid (ursocholic acid) and ursodeoxycholic acid on the formation of biliary cholesterol crystals was studied in mice. Cholesterol crystals developed with 80% incidence after feeding for five weeks a lithogenic diet containing 0.5% cholesterol and 0.25% sodium cholate. When 0.25% ursocholic acid or ursodeoxycholic acid was added to the lithogenic diet, the incidence as well as the grade (severity) of the gallstones were reduced. Plasma and liver cholesterol levels were decreased by ursodeoxycholic acid but not by ursocholic acid. Gallbladder cholesterol and phospholipid levels were decreased by both bile acids. The biliary bile acid level was decreased by ursocholic acid but not by ursodeoxycholic acid. After feeding ursocholic acid, its level in the bile was about 25% and the levels of cholic acid and beta-muricholic acid decreased. Fecal sterol excretion was not changed by ursocholic acid, but was increased by ursodeoxycholic acid. After feeding ursocholic acid, fecal excretion of deoxycholic acid, cholic acid, and ursocholic acid increased. No differences were found between mice, with or without gallstones, in plasma and liver cholesterol levels, biliary phospholipid and bile acid levels, fecal sterol and bile acid levels, and biliary and fecal bile acid composition. The results suggest that the lower incidence of crystal formation after treatment with ursocholic acid is probably by a different mechanism than with ursodeoxycholic acid. In the mouse model, ursodeoxycholic acid exerts its effect at least partially, by decreasing cholesterol absorption. Ursocholic acid is well absorbed and excreted into bile and transformed into deoxycholic acid by the intestinal microflora in mice.

The prevention of experimental cholesterol gallstones by ileectomy in mice.

After a lithogenic diet containing 0.5 per cent cholesterol and 0.25 per cent sodium cholate was fed to a group of normal Crj-ICR male mice for 10 days, cholesterol gallstones developed. No formation of gallstones occurred, however, in a group of mice from which 20 cms of terminal ileum had been removed prior to the feeding of the lithogenic diet. The biliary concentrations of cholesterol, phospholipids and bile acids were markedly lower in the ileectomized mice, with the decrease in cholesterol concentration being most significant. On the other hand, fecal excretion of sterols and bile acids increased in the ileectomized mice. The pool size of bile acids increased after the feeding of the lithogenic diet, but ileectomy decreased the pool size in mice fed the ordinary or lithogenic diets. The biliary concentration of cholic acid increased after the feeding of the lithogenic diet, but decreased with ileectomy. The biliary concentration and fecal excretion of deoxycholic acid markedly increased, while those of beta-muricholic acid and its secondary bile acids, omega-muricholic acid and hyodeoxycholic acid, decreased. The increase in plasma and liver cholesterol levels after the feeding of the lithogenic diet was prevented by ileectomy. These data suggest that ileectomy prevents the formation of cholesterol gallstones after the feeding of a lithogenic diet due to a decrease in cholic acid absorption.

Fecal bile acid excretion pattern in cholecystectomized patients

The fecal bile acid excretion pattern was investigated in 25 cholecystectomized and 26 noncholecystectomized patients as a measure for the exposure of the colonic mucosa to bile acids. Separation of free, conjugated, and sulfated bile acids was achieved by liquid-gel chromatography using DEAP Sephadex LH-20 and quantification of individual bile acids by gas-liquid chromatography. Total bile acid concentration was higher in cholecystectomized (5.33 +/- 0.71 mg/g) than in noncholecystectomized patients (3.69 +/- 0.65 mg/g). Deoxycholic acid excretion was elevated in cholecystectomized patients in three aspects: the concentration of deoxycholic acid was higher (2.92 +/- 0.39 mg/g and 1.71 +/- 0.35 mg/g, respectively), its percentage proportion of total bile acids was increased (53.9 +/- 2.8% and 41.4 +/- 3.1%, respectively), and its daily output was twice as large as that in patients without previous cholecystectomy (63.2 +/- 11.5 and 32.9 +/- 5.9 mg/day, respectively).

Faecal bile acids and the irritable colon syndrome.

Faecal bile acid excretion and rectosigmoid myoelectrical activity were measured on three separate occasions over a 12-month period in 21 patients with the irritable colon syndrome. The results were compared with those of a group of normal subjects. Deoxycholic acid excretion was statistically significantly lower in patients with the irritable colon syndrome. In addition, these patients had a persistently high incidence of 0.03-0.06 Hz (2-4 c/m) rectosigmoid slow-wave electrical activity. These abnormal values persisted throughout the period of the study.

Effect of Dietary Wheat Bran, Alfalfa, Pectin and Carrageenan on Plasma Cholesterol and Fecal Bile Acid and Neutral Sterol Excretion in Rats

The effect of dietary wheat bran, alfalfa, pectin and undegraded carrageenan at a level of 15% on the composition of fecal bile acids and neutral sterols and on the plasma and liver cholesterol levels was studied in Fischer female rats fed a semi-purified diet based on soybean protein, cornstarch, dextrose and corn oil. The diets differed not only in type of fiber but also in amount of fiber. Plasma cholesterol levels were reduced in rats fed pectin or carrageenan diet but were not altered by the addition of wheat bran or alfalfa to the diet. Liver cholesterol levels were comparable in all groups. Diets containing wheat bran, alfalfa and carrageenan caused a significant increase in feces weight. The concentration (mg/g dry feces) of fecal bile acids, particularly hyodeoxycholic acid, β-muricholic acid, deoxycholic acid and lithocholic acid, and of neutral sterols, mainly coprostanol, was lower in rats fed wheat bran compared to those fed a control diet, but the daily output of these constituents was the same in both groups. Alfalfa had no effect on the concentration of fecal bile acids, but the daily excretion of deoxycholic acid, lithocholic acid and 12-ketolithocholic acid was increased compared to the control diet. Addition of pectin to the diet increased the concentration and daily output of fecal neutral sterols and bile acids compared to that of control diet. Carrageenan markedly increased the concentration and daily output of fecal cholesterol, deoxycholic acid and lithocholic acid, as well as the daily output of total bile acids. It is concluded that the plasma cholesterol-lowering effect and fecal bile acid and neutral sterol excretion vary with type and amount of fiber.

Effects of acute caloric restriction on cholesterol metabolism in man

The effects of acute caloric restriction on cholesterol balance and kinetics of plasma cholesterol specific activity were investigated in five hyperlipemic subjects with varying degrees of obesity. Caloric restriction decreased plasma triglycerides by 41 +/- 12%, plasma cholesterol by 11 +/- 9%, and the ratio of esterified to free cholesterol by 12 +/- 7+. Immediately on institution of caloric restriction there appeared to be an influx of tissue cholesterol into plasma and a reduction in endogenous synthesis of cholesterol. The cholesterol balance decreased from 1,469 +/- 441 to 1,212 +/- 349 mg/day and the rate of decay of plasma cholesterol specific activity decreased 62 +/- 3%. The effect of caloric restriction on hepatic synthesis of bile acids was also very prompt. The total fecal bile acids were reduced immediately by 36 +/- 7%. Because the effect on fecal excretion of deoxycholic acid was greater than that on fecal lithocholic acid, it was suggested that hepatic synthesis of cholic acid was reduced more than the synthesis of chenodeoxycholic acid. Caloric restriction did not cause any change in the percentage of absorption of dietary cholesterol (40 +/- 2% versus 42 +/- 3%). These observations are in accord with our model relating cholesterol metabolism with the metabolism of plasma lipoproteins in man.

Effect of glucose administration on cholesterol and bile acid metabolism in rats.

Glucose administered to fasted rats caused a marked stimulation in hepatic cholesterogenesis and cholesterol 7 alpha-hydroxylation, and an increase in biliary excretion of cholesterol and total bile acids. The excretion of cholic acid was not incluenced during the first few hr after glucose administration, but was significantly increased after 5 hr. Chenodeoxycholic acid showed a similar change, but the increase was only ca. one tenth of that of cholic acid. The excretion of deoxycholic acid was markedly increased by 1 hr, but gradually decreased thereafter. Pretreatment with neomycin abolished the increase in deoxycholic acid by fasting and glucose administration. Other bile acid components showed no significant change. It thus was presumed that cholesterol endogenously synthesized in the liver was metabolized mainly to cholic acid. In contrast, exogenous cholesterol was metabolized mainly to chenodeoxycholic acid. During the period of the acute enhancement of cholic acid formation from the endogenous cholesterol, biliary excretion of deoxycholic acid was increased. This probably occurred through the depression of 7 alpha-rehydroxylation of deoxycholic acid, or through the enhancement of microbial formation of deoxycholic acid in the lumen, and through the increase of intestinal absorption.