The metabolism of bile acids with special reference to liver injury

The changing metabolic landscape of bile acids - keys to metabolism and immune regulation

Bile acids regulate nutrient absorption and mitochondrial function, they establish and maintain gut microbial community composition and mediate inflammation, and they serve as signalling molecules that regulate appetite and energy homeostasis. The observation that there are hundreds of bile acids, especially many amidated bile acids, necessitates a revision of many of the classical descriptions of bile acids and bile acid enzyme functions. For example, bile salt hydrolases also have transferase activity. There are now hundreds of known modifications to bile acids and thousands of bile acid-associated genes, especially when including the microbiome, distributed throughout the human body (for example, there are >2,400 bile salt hydrolases alone). The fact that so much of our genetic and small-molecule repertoire, in both amount and diversity, is dedicated to bile acid function highlights the centrality of bile acids as key regulators of metabolism and immune homeostasis, which is, in large part, communicated via the gut microbiome.

Lithocholic Acid Activates Mas-Related G Protein-Coupled Receptors, Contributing to Itch in Mice

The present study focused on lithocholic acid (LCA), a secondary bile acid that contributes to cholestatic pruritus. Although recent studies have found that LCA acts on MAS-related G protein-coupled receptor family member X4 (MRGPRX4) in humans, it is unclear which subtypes of MRGPRs are activated by LCA in mice since there is no precise ortholog of human MRGPRX4 in the mouse genome. Using calcium imaging, we found that LCA could activate mouse Mrgpra1 when transiently expressed in HEK293T cells. Moreover, LCA similarly activates mouse Mrgprb2. Importantly, LCA-induced responses showed dose-dependent effects through Mrgpra1 and Mrgprb2. Moreover, treatment with QWF (an antagonist of Mrgpra1 and Mrgprb2), YM254890 (Gα_q inhibitor), and U73122 (an inhibitor of phospholipase C) significantly suppressed the LCA-induced responses, implying that the LCA-induced responses are indeed mediated by Mrgpra1 and Mrgprb2. Furthermore, LCA activated primary cultures of mouse sensory neurons and peritoneal mast cells, suggesting that Mrgpra1 and Mrgprb2 contribute to LCA-induced pruritus. However, acute injection of LCA did not induce noticeable differences in scratching behavior, implying that the pruritogenic role of LCA may be marginal in non-cholestatic conditions. In summary, the present study identified for the first time that LCA can activate Mrgpra1 and Mrgprb2. The current findings provide further insight into the similarities and differences between human and mouse MRGPR families, paving a way to understand the complex roles of these pruriceptors.

Targeted bile acids and gut microbiome profiles reveal the hepato-protective effect of WZ tablet (Schisandra sphenanthera extract) against LCA-induced cholestasis

Cholestasis is caused by the obstacle of bile formation or secretion and can develop into severe liver diseases. We previously reported the ethanol extract of Schisandra sphenanthera (Wuzhi tablet, WZ) can significantly protect against lithocholic acid (LCA)-induced intrahepatic cholestasis in mice, partially due to the activation of PXR pathway and promotion of liver regeneration. However, the effect of WZ on the bile acids profile and gut microbiome in cholestastic mice remain unknown. In this study, the effect of WZ against LCA-induced liver injury was evaluated and its effect on the bile acids metabolome and gut microbiome profiles in cholestastic mice was further investigated. Targeted metabolomics analysis was performed to examine the change of bile acids in the serum, liver, intestine and feces. The change of intestinal flora were detected by the genomics method. Targeted metabolomics analysis revealed that WZ enhanced the excretion of bile acids from serum and liver to intestine and feces. Genomics analysis of gut microbiome showed that WZ can reverse LCA-induced gut microbiome disorder to the normal level. In conclusion, WZ protects against LCA-induced cholestastic liver injury by reversing abnormal bile acids profiles and alteration of gut microbiome.

Oxidative stress markers, secondary bile acids and sulfated bile acids classify the clinical liver injury type: Promising diagnostic biomarkers for cholestasis

Clinicians sometimes encounter difficulty in choosing a therapeutic strategy due to the uncertainty regarding the type of liver injury. In particular, cholestasis is difficult to diagnose by conventional markers at an early stage of disease. The aim of this study was to identify promising biomarkers for distinguishing the symptom-based types of liver injury (e.g. hepatocellular injury, cholestasis), which was derived from a rigorously statistical perspective. The associations between diagnostic biomarkers (e.g. bile acid components, oxidative stress markers and liver fibrosis markers) and the liver injury types were assessed by a multiple logistic regression analysis using 304 blood samples from patients with liver disease. As a result, reductions in the lithocholic acid (LCA) and deoxycholic acid (DCA) levels, and elevation of the serum sulfated bile acid (SSBA), liver fibrosis marker IV collagen (type IV collagen), hyaluronic acid (HA) and reactive oxygen species (ROS) levels were all significantly associated with cholestasis. On the other hand, elevations in the LCA and type IV collagen levels, and a reduction in the ursodeoxy cholic acid (UDCA) level, were significantly associated with hepatocellular injury. The receiver operating characteristic (ROC) analyses showed that the largest area under the ROC curve (AUC) was found for ROS, followed by DCA, HA, LCA, SSBA and type IV collagen in the cholestatic-type cases. These results indicated that ROS, the secondary bile acid levels such as DCA and LCA, and SSBA are promising biomarkers for cholestasis and for classifying the type of liver injuries. This comprehensive approach will allow for an accurate diagnosis, which will facilitate the selection of an appropriate therapy at the onset of disease.

Key discoveries in bile acid chemistry and biology and their clinical applications: history of the last eight decades

During the last 80 years there have been extraordinary advances in our knowledge of the chemistry and biology of bile acids. We present here a brief history of the major achievements as we perceive them. Bernal, a physicist, determined the X-ray structure of cholesterol crystals, and his data together with the vast chemical studies of Wieland and Windaus enabled the correct structure of the steroid nucleus to be deduced. Today, C24 and C27 bile acids together with C27 bile alcohols constitute most of the bile acid "family". Patterns of bile acid hydroxylation and conjugation are summarized. Bile acid measurement encompasses the techniques of GC, HPLC, and MS, as well as enzymatic, bioluminescent, and competitive binding methods. The enterohepatic circulation of bile acids results from vectorial transport of bile acids by the ileal enterocyte and hepatocyte; the key transporters have been cloned. Bile acids are amphipathic, self-associate in solution, and form mixed micelles with polar lipids, phosphatidylcholine in bile, and fatty acids in intestinal content during triglyceride digestion. The rise and decline of dissolution of cholesterol gallstones by the ingestion of 3,7-dihydroxy bile acids is chronicled. Scientists from throughout the world have contributed to these achievements.

Low dose of oleanolic acid protects against lithocholic acid-induced cholestasis in mice: potential involvement of nuclear factor-E2-related factor 2-mediated upregulation of multidrug resistance-associated proteins

Oleanolic acid (OA) is a natural triterpenoid and has been demonstrated to protect against varieties of hepatotoxicants. Recently, however, OA at high doses was reported to produce apparent cholestasis in mice. In this study, we characterized the protective effect of OA at low doses against lithocholic acid (LCA)-induced cholestasis in mice and explored further mechanisms. OA cotreatment (5, 10, and 20 mg/kg, i.p.) significantly improved mouse survival rate, attenuated liver necrosis, and decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase; more importantly, serum total bile acids and bilirubin, as well as hepatic total bile acids were also remarkably reduced. Gene and protein expression analysis showed that hepatic expression of multidrug resistance-associated protein 2 (Mrp2), Mrp3, and Mrp4 was significantly increased by OA cotreatment, whereas other bile acid metabolism- and transport-related genes, including Na+/taurocholate cotransporter, organic anion transporter 1b2, bile salt export pump, multidrug resistance protein 3, Cyp3a11, Cyp2b10, Sulfotransferase 2a1 (Sult2a1), and UDP-glucuronosyltransferase 1a1 (Ugt1a1), were only slightly changed. OA also caused increased nuclear factor-E2-related factor (Nrf2) mRNA expression and nuclear protein accumulation, whereas nuclear receptors farnesoid X receptor (FXR), pregnane X receptor (PXR), and constitutive androstane receptor were not significantly influenced by OA. Luciferase (Luc) assays performed in HepG2 cells illustrated that OA was a strong Nrf2 agonist with moderate PXR and weak FXR agonism. Finally, in mouse primary cultured hepatocytes, OA dose- and time-dependently induced expression of Mrp2, Mrp3, and Mrp4; however, this upregulation was abrogated when Nrf2 was silenced. In conclusion, OA produces a protective effect against LCA-induced hepatotoxicity and cholestasis, possibly due to Nrf2-mediated upregulation of Mrp2, Mrp3, and Mrp4.

Chronic ischemia and neurocognition

Cognitive impairment from a major stroke as a consequence of carotid disease is an acknowledged clinical outcome; however, cognitive impairment without major stroke is open to discussion. The three recognized mechanisms for cognitive dysfunction from internal carotid artery are microembolization, white-matter disease, and hypoperfusion. The last has been most difficult to characterize physiologically. In this article, the authors review evidence supporting the existence of chronic ischemia in the brain and its direct impact on cognitive functions. By incorporating the pathophysiology of chronic ischemia into the algorithm of the management of carotid artery disease, we may be able to extend the goals of carotid artery revascularization beyond merely preventing stroke to include preventing or reversing cognitive decline.

ME3738 protects against lithocholic acid-induced hepatotoxicity, which is associated with enhancement of biliary bile acid and cholesterol output

ME3738 (22beta-methoxyolean-12-ene-3beta, 24(4beta)-diol), a derivative of soyasapogenol, attenuates liver disease in several models of chronic liver inflammation. In the present study, we have investigated a protective effect of ME3738 in a typical bile acid-induced cholestatic liver model, lithocholate (LCA) feeding mouse. Co-administration of ME3738 resulted in decreases in plasma alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities and hepatic bile acid level, and increases in biliary outputs of bile acid and cholesterol, as compared with the results in mice treated with LCA alone. LCA sulfation by hydroxysteroid sulfotransferase 2a and hydroxylation have been reported to be involved in protection against LCA-induced hepatotoxicity. ME3738-treatment, however, had no clear influence on the hydroxysteroid sulfotransferase 2a protein level and LCA 6alpha-, 6beta- and 7alpha-hydroxylase activities, but increased biliary cholesterol output. Cholate (CA)-treatment has been shown to induce hepatotoxicity in farnesoid X receptor-null mice, which is scarcely dependent on bile acid sulfation and hydroxylation but associated with decreased biliary bile acid output. Co-administration of ME3738 decreased the ALT and ALP activities and hepatic bile acid level, and increased biliary outputs of bile acid and cholesterol in farnesoid X receptor-null mice, as compared with the results in the mice treated with CA. Moreover, a clear correlation between biliary outputs of cholesterol and bile acid was observed in these two bile acid-induced hepatotoxicity mouse models. These results suggest that ME3738 protects against bile acid-induced hepatotoxicity through increased biliary bile acid output that is not related to bile acid metabolism but associated with cholesterol output.

Serum biochemical evaluation of patients with functional pouches ten to 20 years after restorative proctocolectomy

BACKGROUND

Restorative proctocolectomy with an ileal pouch-anal anastomosis is a surgical treatment of choice for ulcerative colitis and familial adenomatous polyposis (FAP). Pouchitis is a significant enigmatic morbidity. In the long-term, these patients, we anticipated, would experience biochemical profiling alterations after years of retaining functionally acceptable pouches. This pilot study was aimed at assessing results of essential biochemical variables more than 10 years after surgery.

METHODS

The investigation was carried out in 91 patients; 39 were women. Eight-eight had ulcerative colitis, while three had FAPs. The hand-sewn ileal reservoirs after mucoso-proctocolectomy were 66 S and 25 J. The analyses were compared short-term vs long-term. Patients were investigated and were their own control.

RESULTS

Long-term, incidence of acute and chronic pouchitis was 2 and 13%. Eleven and 4% of patients had hypomagnesaemia and hypocalcaemia. Mean levels were significantly enhanced (p<0.01 and p<0.0002). Hypomagnesaemia corresponded to episodes of pouchitis and was corrected with oral magnesium and antibiotics. Hypoferric anaemia was diagnosed in 7% and treated with oral iron tablets. Chronic pouchitis and recurrent pouch mucosa bleeding were the cause. Hypohemoglobinemia and hypocyanocobalaminemia were noted in 5% and 5%, respectively. Erythrocyte sedimentation rate and white blood cells were supra-normal in 13 and 10%, which corresponded with pouchitis. A significant (p<0.03) steady rise of mean serum immunoglobulin G without correlation to pouchitis was noted.

CONCLUSION

Long-term functional results did not deteriorate. Pouchitis was a significant enigmatic morbidity. Severe or chronic pouchitis complicated hypoferric and vitamin B(12) anemia and hypomagnesaemia.

Detoxification of lithocholic acid, a toxic bile acid: relevance to drug hepatotoxicity

Lithocholic acid, a monohydroxy, secondary bile acid, is formed by bacterial 7-dehydroxylation of the primary bile acid chenodeoxycholic acid (CDCA) and of the secondary bile acid ursodeoxycholic acid (UDCA). Lithocholic acid and its precursor CDCA are toxic when fed to the rabbit, rhesus monkey, and baboon, but not when CDCA, as well as UDCA, is used for therapeutic purposes in man. Older studies showed that the species specific toxicity of lithocholic acid could be explained by efficient sulfation of lithocholic acid in man and in chimpanzee, but not in the rabbit, rhesus monkey, or baboon. Rodents detoxify lithocholic acid by hydroxylation, but this does not occur in species in which it is toxic. Recent studies suggest that lithocholic acid induces its own detoxification by activating nuclear receptors to promote transcription of genes encoding sulfotransferase. In addition, work with CaCo2 cells suggest that lithocholic acid may undergo sulfation in the enterocyte and be effluxed back into the intestinal lumen. The evolution of trihydroxy bile acids in vertebrates may have occurred to decrease the formation of lithocholic acid. Lithocholic acid is a rare example of a toxic endobiotic; a variety of mechanisms have evolved to solve the problem of efficient detoxification.

Fatty liver hepatitis (steatohepatitis) and obesity: an autopsy study with analysis of risk factors

Steatohepatitis (fatty liver hepatitis), histologically identical to alcoholic disease, occurs in some obese patients after jejunoileal bypass. A similar lesion occurs rarely in obese patients without bypass surgery, but the risk factors are poorly understood. Hepatic steatosis, steatohepatitis and fibrosis were sought in 351 apparently nonalcoholic patients at autopsy and various risk factors were evaluated. Incidence of steatosis and steatohepatitis correlated with the degree of obesity. Steatohepatitis was found in 18.5% of markedly obese patients and 2.7% of lean patients. Additional risk factors for steatohepatitis were type II diabetes, weight loss in the preterminal period shortly before death and intravenous glucose therapy in the last week of life. Severe fibrosis was found in 13.8% of markedly obese patients and in 6.6% of lean patients; this difference was largely explained by the higher prevalence of diabetes in obese groups. The risk factors defined in this study are known to be associated with abnormalities of free fatty acid metabolism. Obesity, type II diabetes and intravenous glucose therapy are associated with hyperinsulinemia, which may inhibit fatty acid oxidation. Obesity and weight loss increase the presentation of fatty acids to the liver. Similar metabolic changes may occur in obese patients after jejunoileal bypass surgery. Thus this study supports the hypothesis that fatty acids have a role in the hepatocellular necrosis found in some obese individuals.

The bile acid composition of gastric contents from neonates with high intestinal obstruction

The study was designed to identify 'atypical' bile acids in gastric contents from three neonates with high intestinal obstruction on the basis that this was likely to represent a rich source of primary bile acids. Cholic acid was the major component, and related 'atypical' bile acids included its C-3 and C-7 oxidation products, its 3 beta-epimer and 2 beta- and 6 alpha-hydroxylation products. Allocholic acid was the only 5 alpha-cholanic acid derivative identified. 7 alpha, 12 alpha-Dihydroxy-3-oxochol-4-en-24-oic acid was found in all three specimens and might be an intermediate in a biosynthetic pathway from cholesterol to cholic acid in which side-chain oxidation precedes at least some of the nuclear changes. Side-chain-hydroxylated derivatives of trihydroxycoprostanic acid were also detected and these may represent intermediates in biosynthetic pathways from cholesterol to cholic acid via 5 beta-cholestan-3 alpha, 7 alpha, 12 alpha-triol. The most abundant bile acid of this type was (25 epsilon)-3 alpha, 7 alpha, 12 alpha, 25-tetrahydroxy-5 beta-cholestan-26-oic acid, which suggested that C-25 hydroxylation may be an important step in the shortening of the C8 side chain of the cholestane triol to the C5 side chain of cholic acid in the neonatal period. Bile acids lacking a substituent at C-12 included chenodeoxycholic acid, its C-3 and C-7 oxidation products, its 3 beta-epimer and its 6 alpha-hydroxylation product (hyocholic acid).

Intestinal bacterial metabolism of protein and bile acids: role in pathogenesis of hepatic disease after jejuno-ileal bypass surgery

Jejunal bacterial colonization and intestinal metabolism of bile acids and protein by bacteria have been investigated in 12 patients with abnormal liver histology following jeujno-ileal bypass surgery for obesity. Aerobic and/or anaerobic colonic flora was present in jejunal aspirates from 8 of 12 bypass patients, but in none of the controls. Intestinal protein metabolism and bile acid deconjugation (measured by urinary indican excretion and 14C-glycocholic acid breath test) was significantly enhanced in bypass patients. Intestinal bacterial overgrowth, with abnormal intestinal metabolism by bacteria of ingested nutrients and bile acids, could contribute to hepatic disease after bypass surgery via the production of endogenous hepatotoxins.

Bile salt metabolism. II. Bile salts and disease

Alterations of bile salt metabolism have been shown in numerous diseases. Liver damage results in elevated serum bile salt concentrations which may be useful as a sensitive index of hepatocellular disease. Changes in the relative proportions of the individual bile salts in serum occur with cholestasis. Urinary excretion of bile salts, largely in the form of sulphates, increases as a compensatory mechanism. Ileal disease or resection causes bile salt melabsorption. The increase in colonic bile salts produces a watery diarrhoea while the decrease in duodenal levels may cause steatorrhoea. Cholelithiasis may result from alteration in the relative proportions of cholesterol, lecithin and bile salts in bile. The mechanism apparently differs in various conditions predisposing to gallstone formation. A primary alteration of bile salt metabolism has been postulated in several other conditions. Considerable interest centres on the importance of metabolites of bile salts in the pathogenesis of colonic carcinoma. Chenodeoxycholic acid is a successful though costly treatment for selected patients with cholesterol gallstones. Bile salt binding agents, such as cholestyramine, are extremely useful especially in the control of pruritus in patients with cholestasis.

Bile salt metabolism. I. The physiology of bile salts

Bile salts are synthesized in the liver from cholesterol, conjugated with glycine or taurine and secreted in bile with cholesterol and lecithin. The molar concentrations of these three lipids determine solubility of cholesterol in bile. Within the gastrointestinal lumen bile salts play an essential role in lipid absorption and faty transport. An efficienct entero-hepatic circulation maintains hepatic bile salt secretion and provides a "feed-back" control of the bile salt and cholesterol metabolism. Potentially hepatotoxic lithocholic acid formed in the intestinal lumen by bacterial action on chenodeoxycholic acid is sulphated in the liver thus decreasing intestinal reabsorption. The total faecal excretion of bile salts balances hepatic synthesis and represents a major catabolic path in cholesterol metabolism.

[Morphologic investigations on the toxicity of orally applied CDCA in the liver, gastro intestinal tract, kidney and adrenal gland of the rat (author's transl)]

Light- and electron microscopic alterations of the liver and light microscopic findings in the gastro intestinal tract, the kidney and adrenal gland of 80 female Wistar-Rats under CDCA therapy are reported. CDCA was applied by means of an endopharnygeal tube over a period of 60 days in doses of 150, 250, 500 and 1000 mg/kg body weight. The organs were examined at different times. We compared the achieved findings to results obtained already beforehand by light- and electron microscopy after application of 20, 50 and 90 mg/kg body weight and day: Up to a dosage of 90 mg/kg morphological changes of the liver were only visible electron optically, from 150 mg/kg onward they could be seen light optically as well. After 60 days a cirrhosis-like picture had developed. The lethal dose was established at 1000 mg/kg. There were no pathological alterations in the gastrointestinal tract and no definite ones in the kidneys. The adrenal glands were unchanged.--Since there are in the rats, in spite of potent mechanisms of detoxication of CDCA and LCA, even at low doses morphological alterations to be seen, the existence of other toxic, at this moment still unknown metabolites is being discussed.

Taurolithocholate inhibits taurocholate uptake by isolated hepatocytes at low concentrations

The cholestatic bile acid taurolithocholate inhibits taurocholate uptake by isolated liver cells non-competitively. Inhibition is instantaneous and inversely related to the cell number in the incubate. The Ki amounts to 7 micron in the presence of 2 mg cellular protein per ml. Secretion of taurocholate by isolated liver cells is not affected by taurolithocholate up to a concentration of 50 micron. This indicates a difference between the carrier for taurocholate uptake and the carrier for taurocholate secretion. Inhibition of bile acid uptake of liver cells may be involved in the pathogenesis of lithocholate-induced cholestasis.

Cholestatic liver disease associated with diphenylhydantoin therapy. Possible pathogenic importance of altered bile salt metabolism

A ten-year-old boy persented with a prolonged cholestatic liver disease 5 weeks after starting diphenylhydantoin therapy. The initial phase of his illness was characterized by hepatocellular damage with swollen liver cells and centrilobular cholestasis. Severe hyperlipoproteinemia with eruptive xanthomata developed within 3 weeks of his initial jaundice. The second phase of his illness was characterized by portal tract inflammation with bile ductular proliferation and chronic cholestasis gradually resolving over a period of 15 months. It is postulated that diphenylhydantoin sensitivity produced swollen hepatocytes with hypertrophy of the smooth endoplasmic reticulum, reducing hepatic sinusoidal blood flow and the clearance of secondary bile salts. A fall in clearance of lipoproteins, including the cholesterol precursor of primary bile acid synthesis, may have been responsible for a reduction in serum bile acid concentration. High levels of serum lithocholic acid, largely unsulfated presumably due to decreased hepatic uptake, may have produced the prolonged second phase of this illness when histological changes resembled that seen in experimental animals following lithocholic acid administration.

Liver structure and function in cholelithiasis: effect of chenodeoxycholic acid

Although, in suitable patients, oral chenodeoxycholic acid (CDCA) dissolves gallstones, the results of recent animal studies suggest that it might be hepatotoxic. Liver function was therefore studied in patients with gallstones before and during treatment with CDCA and liver biopsies were carried out both in patients with cholelithiasis given bile acid therapy and in those who had been given no medical treatment. In 25 patients treated with 0.5-1.5 g CDCA/day (7-20 mg kg body weight(-1) day(-1)) there was no significant change in serum bilirubin, albumin, globulin, transaminase, isocitric dehydrogenase, alkaline phosphatase, and gamma glutamyl transpeptidase levels before and at monthly intervals during six months' treatment. The kinetics of bromsulphthalein (BSP) clearance and its apparent transport maximum were not significantly changed during CDCA therapy. The mean fasting serum bile acid concentrations of 18.0 +/- SEM 1.2 mumoles/litre before and 20.0 +/- 3.5 mumoles/litre during treatment were both significantly greater than control values. Liver histology was not appreciably different in 11 patients treated with CDCA from that in eight patients with untreated cholelithiasis and in three patients who had received CDCA three to four months before biopsy. These results suggest that in doses of 0.5 to 1.5 g/day CDCA is not hepatotoxic in man.

An analysis of lipoproteins, bile acids, and red cell membranes associated with target cells and spur cells in patients with liver disease

Most patients with stable cirrhosis of the alcoholic have "target" red cells; however, a minority have "spur" cells and severe hemolytic anemia. These two syndromes were studied in 27 patients with target cells and 17 patients with spur cells, all of whom had advanced cirrhosis. The cholesterol and phospholipid content of red cell membranes effectively distinguished target cells from spur cells. Target cells alone were rich in lecithin, and both the cholesterol/phospholipid and cholesterol/lecithin mole ratios were greater in spur cells. The cholesterol/phospholipid mole ratio of both types of red cells correlated closely with the free cholesterol saturation of serum lipoproteins, as defined by the amount of free cholesterol relative to phospholipid and protein in these lipoproteins. Lecithin: cholesterol acyltransferase (LCAT) activity was decreased in most patients with target cells and spur cells; however, the relationship between this activity and the lipid abnormalities observed was weak. Serum bile acid levels also correlated poorly with serum and cell lipids. However, in patients with target cells the amount of cholic and deoxycholic acids in serum was approximately equal to the amount of chenodeoxycholic acid, whereas in patients with spur cells chenodeoxycholic acid (the precursor of lithocholic acid) predominated.

Bile salt secretion in cirrhosis of the liver

Secretion of bile salts into the duodenum was studied in eight normal subjects, in 10 patients with cirrhosis, and in two cholecystectomized subjects. Duodenal juice was aspirated continuously through a double-lumen tube during an unstimulated period, after an intravenous injection of pancreozymin/cholecystokinin, and during a continuous intravenous infusion of secretin given at a rate of 3 units per kilogram body weight per hour. Precautions were taken to try to ensure quantitative recovery during the studies, and recovery of an infused nonabsorbable marker was greater than 80% in all subjects. Secretin induced a flow of a greater volume of juice in the cirrhotic patients than in the normal group (49 to 57 ml per 10 minutes compared with 28 to 49 ml per 10 minutes). This change may have resulted from a higher effective dose of secretin if it is assumed that the cirrhotic liver fails to catabolize secretin. The bile acid response to pancreozymin/cholecystokinin followed by secretin in the cirrhotic subjects resembled that seen in patients after cholecystectomy in whom pancreozymin/cholecystokinin induces only a slight increase in bile salt output but in whom the output of bile salts during rest and secretin stimulation is markedly greater than normal. This response in cirrhosis is probably best interpreted as due to impaired function of the gallbladder. The total amount of bile salt liberated over the two hours of the test in the cirrhotic patients was similar to normal The concentration of bile salt after pancreozymin/cholecystokinin was less than in normal subjects, but similar to that in cholecystectomized patients. It is unlikely therefore that deficient output or concentration of bile salt can be held responsible for steatorrhea in cirrhosis. THERE WAS A MARKED DECREASE IN THE DEOXYCHOLATE CONJUGATES AND A REDUCTION IN THE GLYCINE: taurine ratio in the bile of cirrhotic patients. The former change may reflect a change in bacterial flora and the latter a defect in hepatic conjugating mechanisms.

Chronic cholangitides: aetiology, diagnosis, and treatment

A number of different chronic diseases affect the intrahepatic bile radicles or cholangioles. They include primary and secondary sclerosing cholangitis, primary biliary cirrhosis, chronic cholestatic drug jaundice, atresia, and carcinoma. Aetiological factors include infection, immunological changes, hormones, and congenital defects.Patients with chronic cholestasis have decreased bile salts in the intestinal contents and suffer from a bile salt deficiency syndrome. Failure to absorb dietary fat is managed by a low-fat diet and by medium-chain trigly-cerides which are absorbed in the absence of intestinal bile salts. Fat-soluble vitamin deficiencies are prevented by parenteral vitamins A, D, and K(1). Calcium absorption is defective, and improvement may follow intramuscular vitamin D, medium-chain triglycerides, a low-fat diet, and oral calcium supplements.In partial intestinal bile salt deficiency the anionic bile-salt-chelating resin cholestyramine controls pruritus though steatorrhoea increases. Pruritus associated with total lack of intestinal bile salts is managed by methyl-testosterone or norethandrolone, though the jaundice increases.