Beneficial Effect Of Ursodeoxycholic Acid Research Articles

Diagnosis and therapy of intrahepatic cholestasis of pregnancy.

Intrahepatic cholestasis of pregnancy (ICP) is characterized by the occurrence of pruritus mostly in the third trimenon. Diagnosis is based on the presence of pruritus and elevated levels of serum bile acids in the absence of pruritic skin diseases. There is strong evidence of a genetic predisposition for ICP. Numerous studies have investigated the association of known cholestasis genes such as ABCB4 (also designated MDR3), ABCB11 ( BSEP) and ATP8B1 ( FIC1) with ICP. The results of these studies implicate a heterogeneous etiology of this syndrome. ICP increases the risk of preterm delivery and fetal loss. Furthermore, intense pruritus may necessitate premature induction of labor with its known higher frequency of complications for mother and child. Therefore, ICP pregnancies should be managed as high-risk pregnancies. Pharmaceuticals to alleviate pruritus or improve cholestasis like antihistamines, phenobarbital, anion exchange resins, dexamethasone or S-adenosylmethionine are not widely accepted because of questionable efficacy or side effects. Recent randomized studies have shown beneficial effects of ursodeoxycholic acid (UDCA) on laboratory data and pruritus in patients with ICP. Improved knowledge about the diagnostic classification of different types and pathophysiological mechanisms of ICP may allow for a more targeted treatment of this disease in future.

Effects of Ursodeoxycholic Acid on Splanchnic and Systemic Hemodynamics

Background: Recently, the beneficial effects of ursodeoxycholic acid (UDCA) on the portal hypertensive state have been demonstrated in patients with primary biliary cirrhosis. However, it is not known whether UDCA has direct or indirect effects on the vascular smooth muscles in humans, thereby leading to a change in splanchnic or systemic hemodynamics. Aims: We therefore evaluated the hemodynamic effects of UDCA as to its established effect on gallbladder motility under fasting and postprandial conditions in healthy volunteers. Methods: In a double-blind, cross-over study of 20 healthy volunteers, placebo or UDCA (750 mg/d) were randomly administered over 4 weeks with an interim 4-week washout period. Portal blood flow, cardiac output and gallbladder motility were measured using echo-Doppler and b-mode sonography before and after placebo and verum, respectively. ECG, blood pressure, heart rate and blood chemistry were also measured. Results: UDCA did not significantly change fasting portal flow or meal-induced portal hyperemia. Both fasting and postprandial gallbladder volumes increased (26.5 ± 6.0 vs. 40.7 ± 13.8 ml, p < 0.05, and 11.2 ± 6.2 vs. 14.8 ± 6.7 ml, p < 0.05). Diastolic blood pressure decreased under UDCA (71.2 ± 8.7 vs. 66.5 ± 6.5 mm Hg, p < 0.05). Serum levels of chloride and γ-glutamyltransferase decreased slightly, while alkaline phosphatase increased. Conclusions: UDCA affected systemic but not portal hemodynamics. The increase in gallbladder volume is obviously mediated by factors that do not influence the splanchnic vascular bed.

GUDC Inhibits CytochromecRelease from Human Cholangiocyte Mitochondria

Although ursodeoxycholic acid (UDC) is considered effective treatment for primary biliary cirrhosis (PBC), its mechanism of action is unclear. We tested the hypothesis that UDC is taken up by cholangiocytes and inhibits caspase 3-dependent apoptosis. We used the human cholangiocyte cell line (H69) and assessed it for expression and function of an apical sodium-dependent bile acid transporter (ASBT) by RT-PCR and uptake of tritiated taurocholic acid. We experimentally induced apoptosis in H69 cells using beauvericin (BV) and determined caspase 3 activation using a fluorogenic substrate and mitochondrial cytochromecrelease (CC) into the cytosol by immunoblot analysis. We found that a functional ASBT is expressed by H69 cells as demonstrated by RT-PCR and bile acid uptake studies. Exposure of H69 cells to BV induced apoptosis in 39.4 ± 1.3% of cells at 2 h (0.23 ± 0.2% in controls). In contrast, when H69 cells were preincubated with GUDC (50 mM) for 24 h and then exposed to BV, apoptosis was inhibited by 23% (P< 0.03). In cholangiocytes pretreated with GUDC for 24 h and those treated with BV for 2 h, caspase 3-like activity was reduced by 79% and mitochondrial CC release was inhibited. In summary, the human cholangiocyte cell line H69 possesses a functional bile acid transporter, and GUDC decreases BV-induced apoptosis and inhibits activity of caspase 3 protease by blocking CC release from mitochondria. These preliminary results are consistent with our hypothesis that the beneficial effect of UDC on PBC may involve decreased apoptosis after GUDC uptake by cholangiocytes.

Beneficial effect of ursodeoxycholic acid on serum gamma-GTP in patients with biliary atresia following living related liver transplantation.

Beneficial effect of ursodeoxycholic acid on serum gamma-GTP in patients with biliary atresia following living related liver transplantation.

Beneficial effect of ursodeoxycholic acid on alterations induced by cholestasis of pregnancy in bile acid transport across the human placenta

Background/Aims: The existence of impairment in bile acid transport across the placenta during intrahepatic cholestasis of pregnancy and the effect of ursodeoxycholic acid treatment (1 g/day) were investigated. Methods: Kinetic parameters were calculated from experiments carried out on membrane vesicles obtained from basal (TPMb, fetal-facing) and apical (TPMa, maternal-facing) trophoblast plasma membranes. Bile acid uptake was measured using varying concentrations of [ 14C]-glycocholate and a rapid filtration technique. Results: The maximal velocity of transport (Vmax), the apparent affinity constant (Kt) and the efficiency (Ef) of transport (Vmax/Kt) of the anion:bile acid exchanger located at the TPMb were reduced in intrahepatic cholestasis of pregnancy. Ursodeoxycholic acid induced a reversal of Vmax, Kt and Ef to normal values. Owing to the 3-fold increase in Vmax, with no change in Kt, intrahepatic cholestasis of pregnancy induced an enhancement in Ef of ATP-independent bile acid transport across TPMa. Both Vmax and Ef were restored to normal values by ursodeoxycholic acid. Finally, in ATP-dependent bile acid transport across TPMa, a reduction in the Ef due to an increase in Vmax together with a more pronounced increase in Kt was found. This impairment was also reversed by ursodeoxycholic acid. Conclusions: These results suggest that placenta bile acid transport systems are impaired in intrahepatic cholestasis of pregnancy. Moreover, together with the confirmed beneficial effect for intrahepatic cholestasis of pregnancy patients, such as the relief of pruritus and the improvement in biochemical markers of cholestasis, ursodeoxycholic acid treatment restores the ability of the placenta to carry out vectorial bile acid transfer.

Effect of deoxycholic acid and ursodeoxycholic acid on lipid peroxidation in cultured macrophages.

Kupffer cells are essential for normal hepatic homeostasis and when stimulated, they secrete reactive oxygen species, nitric oxide, eicosanoids, and cytokines. Some of these products are cytotoxic and attack nucleic acids, thiol proteins, or membrane lipids causing lipid peroxidation. Hydrophobic bile acids, such as deoxycholic acid (DCA), can damage hepatocytes by solubilising membranes and impairing mitochondrial function, as well as increasing the generation of reactive oxygen species. The hypothesis that hydrophobic bile acids could stimulate Kupffer cells to increase their capacity to generate reactive oxygen species by measuring cellular lipid peroxidation was tested. Because the hydrophilic bile acid, ursodeoxycholic acid (UDCA) can block hydrophobic bile acid induced cellular phenomena, it was also hypothesised that UDCA could antagonise macrophage activation by hydrophobic bile acids to blunt their capacity to generate reactive oxygen species. J-774A.1 murine macrophages were incubated for 24 hours with either 10(-5) M and 10(-4) M (final concentration) DCA alone, or 10(-4) M UDCA alone, or a mixture of 10(-4) M 1:1 molar ratio of DCA and UDCA. At the end of the incubation period, the culture medium was collected for determination of cellular lipid peroxidation by measuring the malondialdehyde (MDA) content in the medium with the thiobarbituric acid reactive substances assay. 10(-5) M and 10(-4) M DCA increased MDA generation by cultured macrophages. 10(-4) M UDCA alone did not increase MDA generation but blocked the peroxidative actions of DCA. Hydrophobic bile acids, after their hepatic retention, can oxidatively activate Kupffer cells to generate reactive oxygen species. Because UDCA can block this action, the beneficial effect of UDCA is, in part, related to its ability to act as an antioxidant.

Effects of bile acids on human hepatic mitochondria

Objectives: The mechanisms underlying hepatic damage in cholestasis and the beneficial effect of ursodeoxycholic acid (UDCA) are unclear. It has been hypothesized that hydrophobic bile acids retained in the hepatocytes damage mitochondria, but that UDCA is less damaging and even directly protective. We examined the effect of taurine conjugates of UDCA and other bile acids on the electron transport chain of human hepatic mitochondria to determine whether tauro-UDCA can modulate the potentially toxic effects of more hydrophobic bile acids. Methods: Wedge liver biopsies (n = 6) were obtained from individuals without liver disease

Ursodeoxycholic Acid Therapy in Treatment of Primary Sclerosing Cholangitis

The beneficial effects of ursodeoxycholic acid (UDCA) in patients with primary biliary cirrhosis led to therapeutic trials with this bile acid for the treatment of PSC. In two prospective placebo-controlled trials, UDCA led to a significant improvement of AP, GGT, ALT, AST, and, in one study, also of serum bilirubin. In both studies liver histology improved significantly, mainly due to a decrease of cellular infiltrates in portal triads. Pruritus and fatigue improved in approximately one-third of the patients, but, compared to placebo, this effect was not significant. In a follow-up study after on average 3.1 years of UDCA treatment, 7/43 of the patients with stages I-IV disease developed a stenosis of the common bile duct which was effectively treated by endoscopic dilatations. Of 57 patients with PSC included since 1987 in the study, 14 dropped out and of these in 10 information on the outcome is available. In patients treated by UDCA and, whenever necessary, by endoscopic dilatations, the frequency of transplantations was significantly reduced in comparison to patients who dropped out of the study. Bile duct carcinoma developed in 5% of our patients. The data indicate that treatment of patients with PSC with UDCA and by endoscopic dilatations of common duct stenoses is promising. In patients with endstage disease, the only effective therapy is liver transplantation. Therefore, the early diagnosis of the disease seems very important.

Tauroursodeoxycholic acid stimulates hepatocellular exocytosis and mobilizes extracellular Ca++ mechanisms defective in cholestasis.

To assess the effects of tauroursodeoxycholic acid (TUDCA) on bile excretory function, we examined whether TUDCA modulates vesicular exocytosis in the isolated perfused liver of normal rats in the presence of high (1.9 mM) or low (0.19 mM) extracellular Ca++ and in cholestatic rats 24 h after bile duct ligation. In addition, the effects of TUDCA on Ca++ homeostasis were compared in normal and in cholestatic hepatocytes. In the isolated perfused rat liver, TUDCA (25 microM) stimulated a sustained increase in the biliary excretion of horseradish peroxidase, a marker of the vesicular pathway, in the presence of high, but not low extracellular Ca++ or in the cholestatic liver. In contrast, TUDCA stimulated bile flow to the same extent regardless of the concentration of extracellular Ca++ or the presence of cholestasis. In indo-1-loaded hepatocytes, basal cytosolic free Ca++ ([Ca++]i) levels were not different between normal and cholestatic cells. However, in cholestatic cells [Ca++]i increases induced by TUDCA (10 microM) and its 7 alpha-OH epimer taurochenodeoxycholic acid (50 microM) were reduced to 22% and 26%, respectively, compared to normal cells. The impairment of TUDCA-induced [Ca++]i increase in cholestatic cells could be mimicked by exposing normal cells to low extracellular Ca++ (21%) or to the Ca++ channel blocker NiCl2 (23%). These data indicate that (a) dihydroxy bile acid-induced Ca++ entry may be of functional importance in the regulation of hepatocellular vesicular exocytosis, and (b) this Ca++ entry mechanism across the plasma membrane is impaired in cholestatic hepatocytes. We speculate that the beneficial effect of ursodeoxycholic acid in cholestatic liver diseases may be related to the Ca+(+)-dependent stimulation of vesicular exocytosis by its conjugate.

Immunomodulatory effects of ursodeoxycholic acid on immune responses.

Ursodeoxycholic acid was recently recognized as an effective agent in the treatment of primary biliary cirrhosis. Experimental evidence supporting the usefulness of ursodeoxycholic acid as a potentially beneficial therapeutic agent for primary biliary cirrhosis has been reported from the biochemical and physiological aspects. In this study, we investigated the direct effects of ursodeoxycholic acid on immunoglobulin and cytokine production in vitro using plaque-forming cell assay and enzyme-linked immunosorbent assay. It was demonstrated that ursodeoxycholic acid suppressed the production of IgM, IgG and IgA induced by Staphylococcus aureus Cowan I in peripheral blood mononuclear cells derived from healthy subjects and patients with primary biliary cirrhosis and also in human B lymphoma cell lines. Furthermore, ursodeoxycholic acid suppressed interleukin-2 and interleukin-4 production induced by concanavalin A and interferon-gamma production induced by polyinosinic-polycytidylic acid, but it did not affect interleukin-1 and interleukin-6 production induced by lipopolysaccharide in peripheral blood mononuclear cells. In addition, ursodeoxycholic acid suppressed the concanavalin A-induced thymocyte proliferation mediated by interleukin-1. Cytotoxicity against lymphocytes was not observed at the concentrations of ursodeoxycholic acid used. These results suggest that the beneficial effect of ursodeoxycholic acid in primary biliary cirrhosis is mediated in part by immunosuppression.

Effect of ursodeoxycholic acid on the kinetics of the major hydrophobic bile acids in health and in chronic cholestatic liver disease.

Beneficial effects of ursodeoxycholic acid in chronic cholestatic liver diseases have been attributed to displacement of hydrophobic bile acids from the endogenous bile acid pool. To test this hypothesis, we determined pool sizes, fractional turnover rates, synthesis/input rates and serum levels of deoxycholic acid and chenodeoxycholic acid before and 1 mo after the start of treatment with ursodeoxycholic acid (13 to 15 mg/kg body wt/day) in four healthy volunteers and five patients with chronic cholestatic liver diseases (three with primary biliary cirrhosis and two with primary sclerosing cholangitis). Bile acid kinetics were determined by combined capillary gas chromatography-isotope ratio mass spectrometry in serum samples after administration of [2H4] deoxycholic acid and [13C]chenodeoxycholic acid. In healthy volunteers, deoxycholic acid pool sizes decreased during administration of ursodeoxycholic acid by 72%. In patients with cholestatic liver diseases, deoxycholic acid pool sizes before ursodeoxycholic acid treatment were only 13% of those in healthy volunteers and were unaffected by ursodeoxycholic acid treatment. Chenodeoxycholic acid pool sizes were not different in healthy volunteers and in patients with cholestatic liver disease, and were not altered by ursodeoxycholic acid treatment. In both healthy volunteers and patients with cholestatic liver disease, synthesis/input rates and serum levels of deoxycholic acid and chenodeoxycholic acid were not altered by ursodeoxycholic acid treatment. Because in our patients improvement of serum liver tests during short-term ursodeoxycholic acid treatment was noted without a decrease of the pool sizes of the major hydrophobic bile acids, we conclude that displacement of hydrophobic endogenous bile acids is not the mechanism of action of ursodeoxycholic acid in chronic cholestatic liver disease.

Tauro β-muricholate is as effective as tauroursodeoxycholate in preventing taurochenodeoxycholate-induced liver damage in the rat

Cholestasis and enhanced biliary leakage of proteins such as lactate dehydrogenase (LDH) and albumin are known to be induced by infusions of relatively toxic bile salts such as taurocholate (TC) and taurochenodeoxycholate (TCDC). Tauroursodeoxycholate (TUDC) was previously shown to prevent these bile abnormalities when simultaneously infused (1–5). In the present study, we examined whether tauro β-muricholate (T β-MC) has a similar effect. The enhanced biliary excretion of LDH and albumin induced by the infusion of TCDC at a rate of 0.4 umol/min/100 g was markedly prevented by the simultaneous infusion of T β-MC or TUDC at a rate one-fourth that of TCDC. Increased LDH level in plasma and hemolysis caused by the infusion of TCDC were also reduced by either T β-MC or TUDC. These results indicate that T β-MC has a preventive effect on TCDC-induced hepatobiliary changes, which is as efficient as that of TUDC as shown previously, suggesting that the 7 β-hydroxy group is important for this hepatoprotective effect. Furthermore, our results suggest that β-muricholic acid may also have clinical value since current reports demonstrate a beneficial effect of ursodeoxycholic acid on a variety of cholestatic conditions, including primary biliary cirrhosis.

Characterization of serum and urinary bile acids in patients with primary biliary cirrhosis by gas-liquid chromatography-mass spectrometry: effect of ursodeoxycholic acid treatment.

We have studied the effect of ursodeoxycholic acid on the serum and urinary bile acids in seven patients with moderate to severe primary biliary cirrhosis. Bile acids were characterized by gas-liquid chromatography-mass spectrometry and quantified by capillary gas-liquid chromatography. Serum bile acids were elevated 26-fold over control values, with 2.2 times more cholic acid than chenodeoxycholic acid. Urinary bile acid output was elevated 22-fold over control values with a cholic acid:chenodeoxycholic acid ratio of 1.6. In addition, lithocholic acid, deoxycholic acid, ursodeoxycholic acid, 1 beta-hydroxycholic acid, 1 beta-hydroxydeoxycholic acid, and hyocholic acid were identified in both serum and urine; the proportions of the 1- and 6-hydroxylated bile acids were much higher in urine than in serum of the patients (32.1% versus 4.2%). Three months of placebo administration did not change the serum and urinary bile acid composition. In contrast, ursodeoxycholic acid feeding (12-15 mg/kg body weight per day) for 6 months resulted in a 25% decline in the total serum bile acid concentration from the pretreatment values. The proportion of ursodeoxycholic acid increased from 2.1 to 41.2% of total bile acids, so that total fasting serum endogenous bile acid levels decreased 62.4%. Ursodeoxycholic acid feeding substantially increased urinary bile acid output, with ursodeoxycholic acid comprising 58.1%. The proportion of 1- and 6- hydroxylated endogenous bile acids was reduced by 45.5% from pretreatment levels and approximately 4.5% of the urinary bile acids were omega-muricholic acid, 1 beta-hydroxyursodeoxycholic acid, and 21-hydroxyursodeoxycholic acid. These results demonstrate significant changes in the serum and urinary bile acid pattern in primary biliary cirrhosis during ursodeoxycholic acid treatment. The beneficial effect of ursodeoxycholic acid may be due to reduction of the hydroxylated derivatives of endogenous bile acids together with the appearance of hydroxylated derivatives of ursodeoxycholic acid or it may be due to displacement of the more hydrophobic endogenous bile acids by the hydrophilic ursodeoxycholic acid.