miR-21 ablation and obeticholic acid ameliorate nonalcoholic steatohepatitis in mice

This corrects the article DOI: 10.1038/cddis.2017.172.

The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease

Background

Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD.

Aim

The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone.

Methods

Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry.

Results

The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD.

Conclusions

Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.

miR-21 ablation and obeticholic acid ameliorate nonalcoholic steatohepatitis in mice

microRNAs were recently suggested to contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD), a disease lacking specific pharmacological treatments. In that regard, nuclear receptors are arising as key molecular targets for the treatment of nonalcoholic steatohepatitis (NASH). Here we show that, in a typical model of NASH-associated liver damage, microRNA-21 (miR-21) ablation results in a progressive decrease in steatosis, inflammation and lipoapoptosis, with impairment of fibrosis. In a complementary fast food (FF) diet NASH model, mimicking features of the metabolic syndrome, miR-21 levels increase in both liver and muscle, concomitantly with decreased expression of peroxisome proliferator-activated receptor α (PPARα), a key miR-21 target. Strikingly, miR-21 knockout mice fed the FF diet supplemented with farnesoid X receptor (FXR) agonist obeticholic acid (OCA) display minimal steatosis, inflammation, oxidative stress and cholesterol accumulation. In addition, lipoprotein metabolism was restored, including decreased fatty acid uptake and polyunsaturation, and liver and muscle insulin sensitivity fully reinstated. Finally, the miR-21/PPARα axis was found amplified in liver and muscle biopsies, and in serum, of NAFLD patients, co-substantiating its role in the development of the metabolic syndrome. By unveiling that miR-21 abrogation, together with FXR activation by OCA, significantly improves whole body metabolic parameters in NASH, our results highlight the therapeutic potential of nuclear receptor multi-targeting therapies for NAFLD.

Nanoformulations of a potent copper-based aquaporin inhibitor with cytotoxic effect against cancer cells

AIM

Development of liposomal formulations of Cuphen, a potent copper-based aquaporin inhibitor with therapeutic potential against melanoma and colon cancer.

MATERIALS & METHODS

Cuphen was incorporated into liposomes using the dehydration-rehydration method. The ability of Cuphen to induce cancer cell death was evaluated by MTS and ViaCount assays. In vivo toxicity studies were performed in BALB/c mice.

RESULTS

In vitro studies illustrated the antiproliferative effects of Cuphen in different cancer cell lines, in free form or after incorporation into liposomes. In vivo studies revealed no toxic effects after parenteral administration of Cuphen liposomes.

CONCLUSIONS

Cuphen liposomes are highly attractive to be further tested in murine models due to the possibility of stabilizing and specifically deliver this metallodrug to tumor sites.

Tauroursodeoxycholic acid increases neural stem cell pool and neuronal conversion by regulating mitochondria-cell cycle retrograde signaling

The low survival and differentiation rates of stem cells after either transplantation or neural injury have been a major concern of stem cell-based therapy. Thus, further understanding long-term survival and differentiation of stem cells may uncover new targets for discovery and development of novel therapeutic approaches. We have previously described the impact of mitochondrial apoptosis-related events in modulating neural stem cell (NSC) fate. In addition, the endogenous bile acid, tauroursodeoxycholic acid (TUDCA) was shown to be neuroprotective in several animal models of neurodegenerative disorders by acting as an anti-apoptotic and anti-oxidant molecule at the mitochondrial level. Here, we hypothesize that TUDCA might also play a role on NSC fate decision. We found that TUDCA prevents mitochondrial apoptotic events typical of early-stage mouse NSC differentiation, preserves mitochondrial integrity and function, while enhancing self-renewal potential and accelerating cell cycle exit of NSCs. Interestingly, TUDCA prevention of mitochondrial alterations interfered with NSC differentiation potential by favoring neuronal rather than astroglial conversion. Finally, inhibition of mitochondrial reactive oxygen species (mtROS) scavenger and adenosine triphosphate (ATP) synthase revealed that the effect of TUDCA is dependent on mtROS and ATP regulation levels. Collectively, these data underline the importance of mitochondrial stress control of NSC fate decision and support a new role for TUDCA in this process.

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ‘accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. ‘Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death.

IL-17 and IL-22 serum cytokine levels in patients with squamous intraepithelial lesion and invasive cervical carcinoma

PURPOSE

Several works correlate the synthesis of IL-17 and IL-22 with tumoral progression. However, there are no studies of these cytokines on cervical cancer. The authors studied the concentration of IL-17 and IL-22 on serum obtained from patients with different grades of squamous intraepithelial lesions (SILs) and invasive cervical carcinoma.

MATERIALS AND METHODS

Eighty-one women were enrolled in this study, including 23 in the healthy control (with no history of infection or lesions), 11 with low-grade squamous intraepithelial lesion (LSIL), 36 with high-grade squamous intraepithelial lesion (HSIL), and 11 who were diagnosed anatomo-pathologically with invasive carcinoma. Levels of the IL-17 and IL-22 cytokines were measured in the serum obtained from these patients using the enzyme-linked immunoabsorbent assay (ELISA) method.

RESULTS

IL-17 and IL-22 displayed a similar pattern of results, with an increase in the serum level of LSIL patients, when compared with serum from HSIL patients (respectively, mean- pg/ml: 22.50 vs 12.20, and 168.2 vs 61.48, p < 0.05).

CONCLUSION

Concentrations of IL-17 and IL-22 in the peripheral blood of patients with LSIL were increased compared to HSIL patients.

A bile acid protects against motor and cognitive deficits and reduces striatal degeneration in the 3-nitropropionic acid model of Huntington's disease

There is currently no effective treatment for Huntington's disease (HD), a progressive, fatal, neurodegenerative disorder characterized by motor and cognitive deterioration. It is well established that HD is associated with perturbation of mitochondrial energy metabolism. Tauroursodeoxycholic acid (TUDCA), a naturally occurring bile acid, can stabilize the mitochondrial membrane, inhibit the mitochondrial permeability transition, decrease free radical formation, and derail apoptotic pathways. Here we report that TUDCA significantly reduced 3-nitropropionic acid (3-NP)-mediated striatal neuronal cell death in cell culture. In addition, rats treated with TUDCA exhibited an 80% reduction in apoptosis and in lesion volumes associated with 3-NP administration. Moreover, rats which received a combination of TUDCA + 3-NP exhibited sensorimotor and cognitive task performance that was indistinguishable from that of controls, and this effect persisted at least 6 months. Bile acids have traditionally been used as therapeutic agents for certain liver diseases. This is the first demonstration, however, that a bile acid can be delivered to the brain and function as a neuroprotectant and thus may offer potential therapeutic benefit in the treatment of certain neurodegenerative diseases.

Selective recovery of solutes from ionic liquids by pervaporation--a novel approach for purification and green processing

Non-porous membranes with the selective layer consisting of hydrophilic or hydrophobic polymers have been applied for the quantitative and selective recovery of solutes with different physico-chemical properties from a room-temperature ionic liquid, ([bmim][PF6]).

The therapeutic effects of ursodeoxycholic acid as an anti-apoptotic agent

The dihydroxy bile acid, ursodeoxycholic acid (UDCA), has been in widespread clinical use in the Western world since the mid 1980s, when it was initially used for gallstone dissolution [1,2] and subsequently for the treatment of chronic cholestatic liver diseases [3,4]. Many clinical trials of UDCA in a variety of cholestatic disorders established biochemical and clinical improvements, and most importantly showed a significant prolongation of transplant-free survival after four years of treatment with UDCA in patients with primary biliary cirrhosis [5]. Despite its clinical efficacy, the precise mechanism(s) by which UDCA improves liver function during cholestasis is still a matter of debate [6]. It was initially considered that the choleretic effect of UDCA, coupled with its ability to cause a marked shift in the composition of the bile acid pool towards hydrophilicity, accounted for its mechanism of action. In recent years, however, it has become evident that UDCA and its conjugated derivatives are capable of exerting direct effects at the cellular, subcellular, and molecular levels by stabilising cell membranes, affecting signal transduction pathways, and regulating immune responses. In addition, we have shown that UDCA plays a unique role in modulating the apoptotic threshold in both hepatic and non-hepatic cells [7-10]. The purpose of this article is to examine the mechanism(s) by which UDCA prevents apoptotic cell death associated with cholestasis. In addition, we will also review a potentially novel and, heretofore, unrecognised role of UDCA as a therapeutic agent in the treatment of non-liver diseases associated with increased levels of apoptosis as a pathogenesis of the disorder.

Mechanism of charged pollutants removal in an ion exchange membrane bioreactor: drinking water denitrification

The mechanism of anionic pollutant removal in an ion exchange membrane bioreactor (IEMB) was studied for drinking water denitrification. This hybrid process combines continuous ion exchange transport (Donnan dialysis) of nitrate and its simultaneous bioreduction to gaseous nitrogen. A nonporous mono-anion permselective membrane precludes direct contact between the polluted water and the denitrifying culture and prevents secondary pollution of the treated water with dissolved nutrients and metabolic products. Complete denitrification may be achieved without accumulation of NO3(-) and NO2(-) ions in the biocompartment. Focus was given to the effect of the concentration of co-ions, counterions, and ethanol on the IEMB performance. The nitrate overall mass transfer coefficient in this hybrid process was found to be 2.8 times higher compared to that in a pure Donnan dialysis process without denitrification. Furthermore, by adjusting the ratio of co-ions between the biocompartment and the polluted water compartment, the magnitude and direction of each individual anion flux can be easily regulated, allowing for flexible process operation and control. Synthetic groundwater containing 135-350 mg NO3(-) L(-1) was treated in the IEMB system. A surface denitrification rate of 33 g NO3(-) per square meter of membrane per day was obtained at a nitrate loading rate of 360 g NO3(-) m(-3)d(-1), resulting in a nitrate removal efficiency of 85%.

Creatine-supplemented diet extends Purkinje cell survival in spinocerebellar ataxia type 1 transgenic mice but does not prevent the ataxic phenotype

It is not known why expression of a protein with an expanded polyglutamine region is pathogenic in spinocerebellar ataxia, Huntington's disease and several other neurodegenerative diseases. Dietary supplementation with creatine improves survival and motor performance and delays neuronal atrophy in the R6/2 transgenic mouse model of Huntington's disease. These effects may be due to improved energy and calcium homeostasis, enhanced presynaptic glutamate uptake, or protection of mitochondria from the mitochondrial permeability transition. We tested the effects of a 2% creatine-supplemented diet and treatment with taurine-conjugated ursodeoxycholic acid, a bile constituent that can inhibit the mitochondrial permeability transition, on ataxia and Purkinje cell survival in a transgenic model of spinocerebellar ataxia type 1. After 24 weeks, transgenic mice on the 2% creatine diet had cerebellar phosphocreatine levels that were 72.5% of wildtype controls, compared to 26.8% in transgenic mice fed a control diet. The creatine diet resulted in maintenance of Purkinje cell numbers in these transgenic mice at levels comparable to wildtype controls, while transgenic mice fed a control diet lost over 25% of their Purkinje cell population. Nevertheless, the ataxic phenotype was neither improved nor delayed. Repeated s.c. ursodeoxycholic acid injections markedly elevated ursodeoxycholic acid levels in the brain without adverse effects, but provided no improvement in phenotype or cell survival in spinocerebellar ataxia type 1 mice. These results demonstrate that preserving neurons from degeneration is insufficient to prevent a behavioral phenotype in this transgenic model of polyglutamine disease. In addition, we suggest that the means by which creatine mitigates against the neurodegenerative effects of an ataxin-1 protein containing an expanded polyglutamine region is through mechanisms other than stabilization of mitochondrial membranes.

Modulation of steady-state messenger RNA levels in the regenerating rat liver with bile acid feeding

Liver regeneration after two thirds partial hepatectomy (PH) is an orchestrated hyperplastic growth process requiring coordinated expression of many genes. The synchronous progression of 95% of the remnant hepatocytes through the cell cycle provides an in vivo model for examining the influence of bile acids on the molecular regulation of hepatocyte replication and growth. In this study, we examined the effects of endogenous deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) on messenger RNA (mRNA) expression and growth rate during liver regeneration. Rats were fed diets containing no addition, 0.4% DCA, UDCA, or both for 14 days; they then underwent 70% PH and were maintained on the diets for an additional 14 days. mRNA transcript levels for a variety of cell cycle-regulated genes were examined post-PH by Northern blot analysis. Bile acid concentrations were determined in liver, isolated nuclei, and plasma by gas chromatography and mass spectrometry. The results indicated that the addition of DCA and UDCA to the diet markedly shifted the bile-acid compositions of liver and plasma. In addition, DCA dramatically altered the abundance of many transcripts post-PH, whereas coadministration of UDCA suppressed the effect. DCA feeding significantly inhibited liver growth through day 3; however, by day 8, it induced an approximately 20% increase in mass compared with controls, UDCA-fed, or combination-fed animals. UDCA was concentrated greater than 20-fold in nuclei compared with whole liver in controls and DCA-fed animals and greater than 2-fold with UDCA feeding. These data suggest that bile acids may have a key role in liver regeneration, which is significantly altered by modulation of the bile-acid pool.

Bilirubin-induced apoptosis in cultured rat neural cells is aggravated by chenodeoxycholic acid but prevented by ursodeoxycholic acid

BACKGROUND/AIMS

Unconjugated bilirubin (UCB) can be neurotoxic in jaundiced neonates and in patients with Crigler-Najjar syndrome. UCB toxicity may culminate in cell death, however, the occurrence of apoptosis has never been investigated. Ursodeoxycholic acid (UDCA) is a strong modulator of the apoptotic threshold in both hepatic and nonhepatic cells. The aims of this study were to determine whether apoptosis plays a role in neural cell death induced by UCB, and to investigate the ability of UDCA to prevent cell death.

METHODS

Cultured rat astrocytes were incubated with UCB (17 and 86 microM) plus albumin (5.7 and 28.7 microM) for 4-22 h. In addition, astrocytes and neurones were treated with either UCB, 50 microM UDCA, or their combination for 4 h. Cultures were scored for nonviable cells by trypan blue dye exclusion. Apoptosis was assessed by Hoechst staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling assay.

RESULTS

UCB induced a concentration- and time-dependent decrease in astrocyte viability. Apoptosis was 4- and 7-fold increased after 4 h exposure to 17 and 86 microM UCB, respectively (P < 0.01). UDCA reduced apoptosis to <7%, which represents a appoximately 60% protection (P < 0.01). Cholic acid was not protective, and chenodeoxyholic acid aggravated UCB toxicity (P < 0.05). Finally, neurones showed a 1.5-fold greater sensitivity than astrocytes to UCB, while UDCA was still protective.

CONCLUSIONS

UCB is toxic to both astrocytes and neurones, causing cell death through an apoptotic process. Moreover, UDCA inhibits UCB-induced apoptosis in neural cells and this could not be mimicked by other bile acids.

Amyloid beta-peptide disrupts mitochondrial membrane lipid and protein structure: protective role of tauroursodeoxycholate

Mitochondria have been implicated in the cytotoxicity of amyloid beta-peptide (A beta), which accumulates as senile plaques in the brain of Alzheimer's disease patients. Tauroursodeoxycholate (TUDC) modulates cell death, in part, by preventing mitochondrial membrane perturbation. Using electron paramagnetic resonance spectroscopy analysis of isolated mitochondria, we tested the hypothesis that A beta acts locally in mitochondrial membranes to induce oxidative injury, leading to increased membrane permeability and subsequent release of caspase-activating factors. Further, we intended to determine the role of TUDC at preventing A beta-induced mitochondrial membrane dysfunction. The results demonstrate oxidative injury of mitochondrial membranes during exposure to A beta and reveal profound structural changes, including modified membrane lipid polarity and disrupted protein mobility. Cytochrome c is released from the intermembrane space of mitochondria as a consequence of increased membrane permeability. TUDC, but not cyclosporine A, almost completely abrogated A beta-induced perturbation of mitochondrial membrane structure. We conclude that A beta directly induces cytochrome c release from mitochondria through a mechanism that is accompanied by profound effects on mitochondrial membrane redox status, lipid polarity, and protein order. TUDC can directly suppress A beta-induced disruption of the mitochondrial membrane structure, suggesting a neuroprotective role for this bile salt.

Tauroursodeoxycholic acid partially prevents apoptosis induced by 3-nitropropionic acid: evidence for a mitochondrial pathway independent of the permeability transition

Ursodeoxycholic acid (UDCA) has been shown to be a strong modulator of the apoptotic threshold in both hepatic and nonhepatic cells. 3-Nitropropionic acid (3-NP), an irreversible inhibitor of succinate dehydrogenase, appears to cause apoptotic neuronal cell death in the striatum, reminiscent of the neurochemical and anatomical changes associated with Huntington's disease (HD). This study was undertaken (a) to characterize further the mechanism by which 3-NP induces apoptosis in rat neuronal RN33B cells and (b) to determine if and how the taurine-conjugated UDCA, tauroursodeoxycholic acid (TUDCA), inhibits apoptosis induced by 3-NP. Our results indicate that coincubation of cells with TUDCA and 3-NP was associated with an approximately 80% reduction in apoptosis (p < 0.001), whereas neither taurine nor cyclosporin A, a potent inhibitor of the mitochondrial permeability transition (MPT), inhibited cell death. Moreover, TUDCA, as well as UDCA and its glycine-conjugated form, glycoursodeoxycholic acid, prevented mitochondrial release of cytochrome c (p < 0.001), which probably accounts for the observed inhibition of DEVD-specific caspase activity and poly(ADP-ribose) polymerase cleavage. 3-NP decreased mitochondrial transmembrane potential (p < 0.001) and increased mitochondrial-associated Bax protein levels (p < 0.001). Coincubation with TUDCA was associated with significant inhibition of these mitochondrial membrane alterations (p < 0.01). The results suggest that TUDCA inhibits 3-NP-induced apoptosis via direct inhibition of mitochondrial depolarization and outer membrane disruption, together with modulation of Bax translocation from cytosol to mitochondria. In addition, cell death by 3-NP apparently occurs through pathways that are independent of the MPT.

Bilirubin and amyloid-beta peptide induce cytochrome c release through mitochondrial membrane permeabilization

BACKGROUND

The pathogenesis of bilirubin encephalopathy and Alzheimer's disease appears to result from accumulation of unconjugated bilirubin (UCB) and amyloid-beta (Abeta) peptide, respectively, which may cause apoptosis. Permeabilization of the mitochondrial membrane, with release of intermembrane proteins, has been strongly implicated in cell death. Inhibition of the mitochondrial permeability is one pathway by which ursodeoxycholate (UDC) and tauroursodeoxycholate (TUDC) protect against apoptosis in hepatic and nonhepatic cells. In this study, we further characterize UCB- and Abeta-induced cytotoxicty in isolated neural cells, and investigate membrane perturbation during incubation of isolated mitochondria with both agents. In addition, we evaluate whether the anti-apoptotic drugs UDC and TUDC prevent any changes from occurring.

MATERIALS AND METHODS

Primary rat neuron and astrocyte cultures were incubated with UCB or Abeta peptide, either alone or in the presence of UDC. Apoptosis was assessed by DNA fragmentation and nuclear morphological changes. Isolated mitochondria were treated with each toxic, either alone or in combination with UDC, TUDC, or cyclosporine A. Mitochondrial swelling was measured spectrophotometrically and cytochrome c protein levels determined by Western blot.

RESULTS

Incubation of neural cells with both UCB and Abeta induced apoptosis (p < 0.01). Coincubation with UDC reduced apoptosis by > 50% (p < 0.05). Both toxins caused membrane permeabilization in isolated mitochondria (p < 0.001); whereas, pretreatment with UDC was protective (p < 0.05). TUDC was even more effective at preventing matrix swelling mediated by Abeta (p < 0.01). UDC and TUDC markedly reduced cytochrome c release associated with mitochondrial permeabilization induced by UCB and Abeta, respectively (p < 0.05). Moreover, cyclosporine A significantly inhibited mitochondrial swelling and cytochrome c efflux mediated by UCB (p < 0.05).

CONCLUSION

UCB and Abeta peptide activate the apoptotic machinery in neural cells. Toxicity occurs through a mitochondrial-dependent pathway, which in part involves opening of the permeability transition pore. Furthermore, membrane permeabilization is required for cytochrome c release from mitochondria and can be prevented by UDC or TUDC. These data suggest that the mitochondria is a pharmacological target for cytoprotection during unconjugated hyperbilirubinemia and neurodegenerative disorders, and that UDC or TUDC may be potential therapeutic agents.

Genomic organization and promoter characterization of the rat cyclin B1 gene

Cyclin B1 is a key regulatory protein involved in cellular mitosis. We have cloned 1.8kb of DNA sequence upstream of the rat cyclin B1 gene translation start site from Rattus norvegicus liver genomic DNA and a commercial rat testis genomic library. The mRNA transcription start point (tsp) was determined by primer extension and mRNA end ligation followed by RT-PCR across the ligated 3' and 5' ends. An authentic tsp was confirmed approximately 100bp upstream of the translation start site. A second potential tsp was also detected approximately 32bp downstream from the first. RT-PCR analysis of rat liver poly(A)(+) RNA using 5'-derived oligonucleotide primers indicated that the 5' end sequence was present in both the 1.6 and 2. 4kb rat liver cyclin B1 mRNA species. Like many other cyclin promoters, there was no apparent TATA box upstream of the transcription initiation sites. However, computer analysis of the promoter region identified a group of consensus transcription factor binding sites, some of which are also reported in other cyclin promoters. These include those for p53, p21, Ap-1, Ap-2, Ets-1, CAATT, E-Box and Yi. We also performed luciferase reporter assays using a set of promoter deletion constructs in human HuH-7 hepatoma and HeLa carcinoma cell lines. Our results suggest that an E-Box and/or CCAAT binding sites are important for transcription, and that there may be negative regulatory elements present between 1800 and 1100bp upstream of the translation start site.

Apoptotic cell death does not parallel other indicators of liver damage in chronic hepatitis C patients

The mechanisms of hepatocyte damage and the events that lead to high rates of chronic liver disease in hepatitis C virus (HCV) infection remain unclear. Recent in vitro studies have suggested that the HCV core protein may disrupt specific signalling pathways of apoptosis. This prompted us to study patients with chronic HCV infection to: determine the extent of apoptosis in the liver; evaluate whether clinical and biochemical data are correlated with histological findings; and to investigate if apoptosis is related to the histological activity of the disease. Twelve patients with chronic hepatitis C were included in the study. Liver histology was scored by using the histological activity index (HAI) of Knodell et al. DNA fragmentation was assessed in liver tissue by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling (TUNEL) assay. Routine methods were used to determine serum markers of liver disease. Bile acids were measured in serum and liver by gas chromatography. Patients were placed, according to their HAI score, into group A (3.8 +/- 0.3) or group B (7.8 +/- 0.8) (P < 0.01). Liver enzymes tended to be higher in group B patients than in patients of group A. Levels of toxic bile acids in serum were greater in patients than in controls (P < 0.01). Chenodeoxycholic acid values were slightly higher in serum and liver of patients in group A. Liver biopsies with low HAI scores showed an increased rate of apoptosis (18.0 +/- 4.0 apoptotic cells per field) compared to those with higher HAI scores (6.6 +/- 2.1, P < 0.05) or to controls (3.5 +/- 0.4, P < 0.01). Hence, less severe liver disease, associated with lower histological grades and biochemistries, as well as increased levels of chenodeoxycholic acid, induces an expanded apoptotic response. The lower apoptotic rate in advanced liver disease may be associated with the high incidence of hepatocellular dysplasia/neoplasia.

Bile acid patterns in meconium are influenced by cholestasis of pregnancy and not altered by ursodeoxycholic acid treatment

BACKGROUND

Data on meconium bile acid composition in newborn babies of patients with intrahepatic cholestasis of pregnancy (ICP) are relatively scant, and changes that occur on ursodeoxycholic acid (UDCA) administration have not been evaluated.

AIMS

To investigate bile acid profiles in meconium of neonates from untreated and UDCA treated patients with ICP. Maternal serum bile acid composition was also analysed both at diagnosis and delivery to determine whether this influences the concentration and proportion of bile acids in the meconium.

PATIENTS/METHODS

The population included eight healthy pregnant women and 16 patients with ICP, nine of which received UDCA (12.5-15.0 mg/kg body weight/day) for 15+/-4 days until parturition. Bile acids were assessed in the meconium by gas chromatography-mass spectrometry and in maternal serum by high performance liquid chromatography.

RESULTS

Total bile acid and cholic acid concentrations in the meconium were increased (p<0.01) in newborns from patients with ICP (13.5 (5.1) and 8.4 (4.1) micromol/g respectively; mean (SEM)) as compared with controls (2.0 (0.5) and 0.8 (0.3) micromol/g respectively), reflecting the total bile acid and cholic acid levels in the maternal serum (r = 0.85 and r = 0.84, p<0.01). After UDCA administration, total bile acid concentrations decreased in the mother ( approximately 3-fold, p<0. 05) but not in the meconium. UDCA concentration in the meconium showed only a 2-fold increase after treatment, despite the much greater increase in the maternal serum (p<0.01). Lithocholic acid concentration in the meconium was not increased by UDCA treatment.

CONCLUSIONS

UDCA administration does not influence the concentration and proportion of bile acids in the meconium, which in turn are altered by ICP. Moreover, this beneficial treatment for the mother does not increase meconium levels of potentially toxic metabolites of UDCA such as lithocholic acid.

Ursodeoxycholic acid prevents cytochrome c release in apoptosis by inhibiting mitochondrial membrane depolarization and channel formation

The hydrophilic bile salt ursodeoxycholic acid (UDCA) is a potent inhibitor of apoptosis. In this paper, we further characterize the mechanism by which UDCA inhibits apoptosis induced by deoxycholic acid, okadaic acid and transforming growth factor beta1 in primary rat hepatocytes. Our data indicate that coincubation of cells with UDCA and each of the apoptosis-inducing agents was associated with an approximately 80% inhibition of nuclear fragmentation (P<0.001). Moreover, UDCA prevented mitochondrial release of cytochrome c into the cytoplasm by 70 - 75% (P<0.001), thereby, inhibiting subsequent activation of DEVD-specific caspases and cleavage of poly(ADP-ribose) polymerase. Each of the apoptosis-inducing agents decreased mitochondrial transmembrane potential and increased mitochondrial-associated Bax protein levels. Coincubation with UDCA was associated with significant inhibition of these mitochondrial membrane alterations. The results suggest that the mechanism by which UDCA inhibits apoptosis involves an interplay of events in which both depolarization and channel-forming activity of the mitochondrial membrane are inhibited.

Elevated levels of bile acids in colostrum of patients with cholestasis of pregnancy are decreased following ursodeoxycholic acid therapy [see comemnts]

BACKGROUND/AIMS

Intrahepatic cholestasis of pregnancy is characterised by increased levels of serum bile acids. Ursodeoxycholic acid therapy corrects the serum bile acid profile. The aims of this study were: (i) to investigate bile acid excretion into colostrum of women with intrahepatic cholestasis of pregnancy; (ii) to compare concentrations of bile acids in serum and colostrum of non-treated and ursodeoxycholic acid-treated patients; and (iii) to clarify whether ursodeoxycholic acid is eliminated into colostrum following treatment.

METHODS

Bile acids were assessed by gas chromatography and high-performance liquid chromatography in serum collected at delivery, and in colostrum obtained at 2+/-1 days after labour, from patients with intrahepatic cholestasis of pregnancy, non-treated (n=9) and treated (n=7) with ursodeoxycholic acid (14 mg/kg bw per day, for 14+/-7 days) until parturition.

RESULTS

The concentration of total bile acids in colostrum from patients with intrahepatic cholestasis of pregnancy was higher than in normals (23.3+/-14.8 micromol/l vs. 0.7+/-0.2 micromol/l, p<0.01) and cholic acid was a major species (19.0+/-13.1 micromol/l), reflecting the elevated concentrations in maternal serum (48.9+/-21.0 micromol/l, total bile acids; 33.9+/-16.7 micromol/l, cholic acid. Following ursodeoxycholic acid administration, total bile acids and cholic acid levels in colostrum diminished to 5.7+/-2.5 micromol/l and 3.6+/-1.5 micromol/l, respectively; the proportion of cholic acid decreased (60.6+/-8.0% vs. 76.8+/-5.0%, p<0.05). The ursodeoxycholic acid concentration in colostrum was maintained following treatment; its increased percentage (9.4+/-3.2% vs. 1.0+/-0.2%, p<0.01) was still lower than in maternal serum (20.8+/-3.6%, p<0.05). Only a small proportion (<1%) of lithocholic acid was found in colostrum following therapy.

CONCLUSIONS

Bile acid concentrations are elevated and cholic acid is the major species accumulating in colostrum, reflecting serum bile acid profiles in intrahepatic cholestasis of pregnancy. Ursodeoxycholic acid therapy decreases endogenous bile acid levels in colostrum.

Relevance of serum bile acid profile in the diagnosis of intrahepatic cholestasis of pregnancy in an high incidence area: Portugal

OBJECTIVE(S)

The present work was conducted to clarify the relevance of usual liver function tests, and define the most predictive serum bile acid profile for diagnosis of intrahepatic cholestasis of pregnancy (ICP).

STUDY DESIGN

This study comprised 20 healthy nonpregnant women and 77 pregnant women in the last trimester of pregnancy, from which 38 were normal pregnancies, and 39 suffered from ICP. Liver function tests were evaluated by routine laboratory techniques, conjugated bile acids were analysed by high-performance liquid chromatography, and unconjugated forms were measured by an enzymatic-fluorimetric assay.

RESULTS

During the third trimester in normal pregnancy, increased concentration of conjugated species affected all primary bile acids, although only significantly for glycocholic acid. Moreover, deoxycholic acid proportion decreased when compared with healthy nonpregnant women. Important ICP-induced changes in serum profiles of amidated bile acids were observed, involving both a marked increase in cholic acid concentration and a shift towards a higher proportion of taurine-conjugated species. Among routine liver tests, alanine aminotransferase and conjugated bilirubin were the most common indicators of ICP.

CONCLUSION(S)

In the early diagnosis and follow-up of ICP, the most predictive and accurate markers (efficiency 100%) were: (i) TBA concentration in serum >11.0 micromol(-1): (ii) cholic/chenodeoxycholic acid ratio >1.5 and cholic acid percentage >42%: (iii) glycine/taurine bile acid ratio <1.0 or glycocholic acid concentration >2.0 micromol(-1). Accurate diagnosis based on sensitive biochemical markers followed by appropriate treatment may improve both pregnancy outcome and newborn prognosis.

A novel role for ursodeoxycholic acid in inhibiting apoptosis by modulating mitochondrial membrane perturbation

The hydrophilic bile salt ursodeoxycholic acid (UDCA) protects against the membrane-damaging effects associated with hydrophobic bile acids. This study was undertaken to (a) determine if UDCA inhibits apoptosis from deoxycholic acid (DCA), as well as from ethanol, TGF-beta1, Fas ligand, and okadaic acid; and to (b) determine whether mitochondrial membrane perturbation is modulated by UDCA. DCA induced significant hepatocyte apoptosis in vivo and in isolated hepatocytes determined by terminal transferase-mediated dUTP-digoxigenin nick end-labeling assay and nuclear staining, respectively (P < 0.001). Apoptosis in isolated rat hepatocytes increased 12-fold after incubation with 0.5% ethanol (P < 0.001). HuH-7 cells exhibited increased apoptosis with 1 nM TGF-beta1 (P < 0. 001) or DCA at >/= 100 microM (P < 0.001), as did Hep G2 cells after incubation with anti-Fas antibody (P < 0.001). Finally, incubation with okadaic acid induced significant apoptosis in HuH-7, Saos-2, Cos-7, and HeLa cells. Coadministration of UDCA with each of the apoptosis-inducing agents was associated with a 50-100% inhibition of apoptotic changes (P < 0.001) in all the cell types. Also, UDCA reduced the mitochondrial membrane permeability transition (MPT) in isolated mitochondria associated with both DCA and phenylarsine oxide by > 40 and 50%, respectively (P < 0.001). FACS(R) analysis revealed that the apoptosis-inducing agents decreased the mitochondrial transmembrane potential and increased reactive oxygen species production (P < 0.05). Coadministration of UDCA was associated with significant prevention of mitochondrial membrane alterations in all cell types. The results suggest that UDCA plays a central role in modulating the apoptotic threshold in both hepatocytes and nonliver cells, and inhibition of MPT is at least one pathway by which UDCA protects against apoptosis.

Ursodeoxycholic acid may inhibit deoxycholic acid-induced apoptosis by modulating mitochondrial transmembrane potential and reactive oxygen species production

BACKGROUND

The hydrophilic bile salt ursodeoxycholate (UDCA) inhibits injury by hydrophobic bile acids and is used to treat cholestatic liver diseases. Interestingly, hepatocyte cell death from bile acid-induced toxicity occurs more frequently from apoptosis than from necrosis. However, both processes appear to involve the mitochondrial membrane permeability transition (MPT). In this study, we determined the inhibitory effect of UDCA on deoxycholic acid (DCA)-induced MPT in isolated mitochondria by measuring changes in transmembrane potential (delta psi m) and production of reactive oxygen species (ROS). In addition, we examined the expression of apoptosis-associated proteins in mitochondria isolated from livers of bile acid-fed animals.

MATERIALS AND METHODS

Adult male rats were maintained on standard diet supplemented with DCA and/or UDCA for 10 days. Mitochondria were isolated from livers by sucrose/percoll gradient centrifugation and MPT was measured using spectrophotometric and fluorimetric assays. delta psi m and ROS generation were determined by FACScan analysis. Cytoplasmic and mitochondrial protein abundance were determined by Western blot analysis.

RESULTS

DCA increased mitochondrial swelling 25-fold over controls (p < 0.001); UDCA reduced the swelling by > 40% (p < 0.001). Similarly, UDCA inhibited DCA-mediated release of calcein-loaded mitochondria by 50% (p < 0.001). delta psi m was significantly decreased in mitochondria incubated with DCA but not with UDCA. delta psi m disruption was followed closely by increased superoxide anion and peroxides production (p < 0.01). Coincubation of mitochondria with UDCA significantly inhibited the changes associated with DCA (p < 0.05). In vivo, DCA feeding was associated with a 4.5-fold increase in mitochondria-associated Bax protein levels (p < 0.001); combination feeding with UDCA almost totally inhibited this increase (p < 0.001).

CONCLUSION

UDCA significantly reduces DCA-induced disruption of delta psi m, ROS production, and Bax protein abundance in mitochondria, suggesting both short- and long-term mechanisms in preventing MPT. The results suggest a possible role for UDCA as a therapeutic agent in the treatment of both hepatic and nonhepatic diseases associated with high levels of apoptosis.

Unusual case of severe cholestasis of pregnancy with early onset, improved by ursodeoxycholic acid administration

An exceptional case of early onset and prolonged postpartum course of intrahepatic cholestasis of pregnancy is described. Contrary to other drugs tested, ursodeoxycholic acid administered after the 29th week of gestation improved pruritus and decreased bile acid levels both in serum and amniotic fluid. Labour was induced at 36 weeks, and a female weighing 2.050 g and with an Apgar score of nine was born. Ursodeoxycholic acid, by decreasing the passage of bile acids to the foetus, may have improved the outcome of the pregnancy.

Correction of maternal serum bile acid profile during ursodeoxycholic acid therapy in cholestasis of pregnancy

BACKGROUND/AIMS

Intrahepatic cholestasis of pregnancy is characterized by pruritus and increased levels of serum bile acids, and is often associated with premature delivery, fetal distress, and perinatal mortality. The aims of the present study were: (i) to better define the serum bile acid profile in intrahepatic cholestasis of pregnancy and its potential usefulness for differential diagnosis; (ii) to investigate the effect of ursodeoxycholic acid treatment on the bile acid pool; and (iii) to investigate possible adverse effects of therapy.

METHODS

Fifteen patients with intrahepatic cholestasis of pregnancy were enrolled in this study. Ursodeoxycholic acid (14 mg/kg body weight per day) was administered for 13 +/- 5 days. Twenty normal pregnant women served as controls. Serum bile acid profile was analyzed by high-performance liquid chromatography.

RESULTS

Patients with cholestasis of pregnancy showed significant alterations in the proportion of primary bile acids, with an increase in cholic acid (64.0 +/- 3.0% vs. 32.2 +/- 1.8%, p < 0.01), and a decrease in chenodeoxycholic acid (20.8 +/- 1.4% vs. 31.9 +/- 1.3%, p < 0.01), as compared to controls, resulting in a marked elevation in the cholic/chenodeoxycholic acid ratio (3.4 +/- 0.5 vs. 1.1 +/- 0.1, p < 0.01). The glycine/taurine ratio was reduced in cholestasis of pregnancy (0.8 +/- 0.1 vs. 1.4 +/- 0.1, p < 0.01). During ursodeoxycholic acid administration its proportion in serum increased from 1.4 +/- 0.6% (0.6 +/- 0.2 micromol/l) at baseline to 24.7 +/- 2.3% (5.9 +/- 1.9 micromol/l) with therapy (p < 0.01). This increment was accompanied by a significant decrease in the percentage of cholic acid (28.2 +/- 2.6%, p < 0.01) and an elevation in chenodeoxycholic acid proportion (25.0 +/- 1.9%, N.S.). Although lithocholic acid concentration in serum was maintained with treatment (1.2 +/- 0.2 micromol/l vs. 1.7 +/- 0.5 micromol/l), there was a significant increase in lithocholic acid proportion (p < 0.01) from 3.3 +/- 0.5% at baseline to 7.4 +/- 1.3% during therapy. The glycine/taurine ratio of serum bile acid pool returned to normal after ursodeoxycholic acid administration (1.7 +/- 0.3).

CONCLUSIONS

These results establish the importance of ursodeoxycholic acid treatment for the correction of maternal serum bile acid profile in cholestasis of pregnancy, indicating that ursodeoxycholic acid may improve fetal prognosis.

Bile acid concentrations in human and rat liver tissue and in hepatocyte nuclei

BACKGROUND & AIMS

Bile acids exert cellular and molecular effects in the liver, but little is known about tissue concentrations. The aim of this study was to characterize bile acid composition in human and rat liver tissue and hepatocyte nuclei and examine the effects of experimental cholestasis and bile acid administration.

METHODS

Bile acids were measured by gas chromatography-mass spectrometry.

RESULTS

Liver tissue concentrations of sham-operated rats were 130.8 +/- 21.3 nmol/g, representing 2%-4% of the bile acid pool; cholic and delta 22-beta-muricholic acids were the major bile acids identified. Concentrations increased 7-8-fold with bile duct ligation; deoxycholate and hyodeoxycholate disappeared. Lithocholate concentrations were higher in ligated rats (6.4 +/- 0.4 vs. 3.9 +/- 0.5 nmol/g for sham-operated). Total bile acid concentrations in human liver tissue were 61.6 +/- 29.7 nmol/g and comprised mainly chenodeoxycholic and cholic acids. Concentrations were higher during ursodeoxycholate or tauroursodeoxycholate administration (157.2 +/- 45.6 and 161.6 +/- 43.4 nmol/g, respectively), and liver tissue was enriched 30% in ursodeoxycholate at the expense of hydrophobic bile acids. Bile acids were identified in rat hepatic nuclei (50-110 pmol/4 x 10(7) nuclei), accounting for < 0.1% of liver tissue levels.

CONCLUSIONS

Human and rat liver tissue bile acid concentrations are low, increase with bile acid administration or bile duct ligation, and account for only a small fraction of the bile acid pool.

Clinical pharmacokinetics of therapeutic bile acids

The pharmacokinetics of chenodeoxycholic and ursodeoxycholic acids are reviewed in this article. Chenodeoxycholic acid is well absorbed by the intestine, whereas the absorption of ursodeoxycholic acid is incomplete. They are extracted efficiently by the liver, conjugated with glycerine and taurine, secreted in bile, and then undergo enterohepatic circulation with the endogenous bile acids. Therapeutic bile acids are metabolised by intestinal bacteria to lithocholic acid which is mainly excreted with faeces. Since the large majority of bile acid is confined within the enterohepatic circulation (resulting in low serum concentrations) their volume of distribution is relatively high. Despite the high hepatic extraction, the clearance of therapeutic bile acids is relatively low because of the highly efficient enterohepatic recirculation. Elimination of therapeutic bile acids mainly occurs in the faeces either unmodified or after biotransformation. At present the main clinical indication for therapeutic bile acids is ursodeoxycholic acid treatment for chronic cholestatic liver disease. In these patients, ursodeoxycholic acid is efficiently absorbed but its hepatic uptake and biliary secretion are impaired, thus leading to reduced biliary enrichment and high serum concentrations of this exogenous bile acid. In patients with cystic fibrosis-associated liver disease, bile acid malabsorption also occurs, thus indicating the need for higher dosages. The volume of distribution and clearance of ursodeoxycholic acid reduced in the presence of liver disease. Also in this case, elimination mainly occurs with the faeces but, in the presence of severe cholestasis, renal clearance may become relevant. Sulphation or conjugation with glucose and N-acetylglucosamine facilitate urinary excretion.

Metabolism of orally administered tauroursodeoxycholic acid in patients with primary biliary cirrhosis

The metabolism of tauroursodeoxycholic acid orally administered and its effects on the bile acid pool of patients with asymptomatic/mildly symptomatic primary biliary cirrhosis is described. Patients were randomly assigned 500, 1000, or 1500 mg/day of tauroursodeoxycholate for six months. Biliary and serum bile acids were measured before and during treatment by gas chromatography-mass spectrometry and by high performance liquid chromatography. During tauroursodeoxycholate administration, the proportion of total ursodeoxycholate in bile reached mean (SEM) 34.4 (4.5)%, 32.8 (2.8)%, and 41.6 (3.0)% with doses of 500, 1000, and 1500 mg/day, respectively. Significant decreases in the proportions of chenodeoxycholate and cholate resulted. The glycine/taurine ratio of the biliary bile acid pool decreased from 1.9 at baseline, to 1.1 with the highest dose. Ursodeoxycholate in bile was conjugated with glycine and taurine, indicating that tauroursodeoxycholate undergoes significant deconjugation and reconjugation during its enterohepatic recycling. The proportion of lithocholate in bile remained unchanged. Fasting serum conjugated ursodeoxycholate concentration positively correlated with the tauroursodeoxycholate dose, and the increased proportion of ursodeoxycholate was accompanied by substantial decreases in the endogenous bile acids. Compared with previously published data for ursodeoxycholic acid therapy, these findings indicate that the shift toward a more hydrophilic bile acid pool is greater and potentially more favourable with tauroursodeoxycholate, and this is because of the reduced intestinal biotransformation of tauroursodeoxycholate.

Formation of delta 22-bile acids in rats is not gender specific and occurs in the peroxisome

We recently demonstrated that the formation of delta 22-bile acids is a quantitatively major pathway for normal bile acid synthesis in the adult male Sprague-Dawley rat. This pathway is specific for 7 beta-hydroxy bile acids and, when ursodeoxycholic acid is administered, delta 22-ursodeoxycholic acid appears as a major metabolite in the liver tissue, bile, intestinal contents, and plasma. The aims of this study were, therefore, to determine whether this metabolic pathway was gender specific, and to establish that the peroxisome is a site of formation of delta 22-bile acids. Bile acids were determined by gas chromatography-mass spectrometry in liver tissue, jejunum, and plasma of adult female rats and in animals fed a diet containing 0.4% and 1% ursodeoxycholic acid. Bile acid metabolism in female rats was found to be similar to that of male rats, and delta 22-beta-muricholic acid, rather than beta-muricholate, was likewise confirmed as the major muricholic acid synthesized. Ursodeoxycholic acid administration resulted in the appearance of delta 22-ursodeoxycholic acid as a major metabolite. When adult male Sprague-Dawley rats were treated with clofibrate, a drug that induces peroxisomal proliferation, liver weight increased 40-60% and total bile acid synthesis decreased markedly, but the relative composition of individual bile acids was unchanged. When ursodeoxycholic acid was added to the diet, the proportion of delta 22-bile acids relative to the corresponding saturated analogues increased significantly compared with untreated rats, indicating that clofibrate had "amplified" the pathway for formation of delta 22-bile acids. When UDCA was incubated in vitro with a peroxisomal-enriched fraction from normal adult male rat liver, delta 22-ursodeoxycholic acid was formed in proportions comparable to that observed in vivo when this bile acid was given orally. These studies establish that the pathway for the formation of delta 22-bile acids is not gender specific and mainly occurs in hepatic peroxisomes.

Performance characteristics of reversed-phase bonded silica cartridges for serum bile acid extraction

The quantitative extraction of bile acids and their conjugates from serum was investigated using different commercially available reversed-phase bonded silica cartridges. Serum was diluted with 0.1 M sodium hydroxide or 0.5 M triethylamine sulphate, pH 7.0, and heated at 64 degrees C for 20-30 min prior to application to the cartridge. Bile acids were adsorbed to the bonded silica particles, and recovered by elution with a small volume of methanol. Dilution of serum with triethylamine sulphate gave quantitative extraction of bile acids from serum using Bond-Elut C18 cartridges, but the milder conditions of the applied sample compared with dilution with sodium hydroxide permitted re-use of the cartridges with no loss in performance, and gave relatively clean extracts. Large variations in the recovery of bile acids were observed using sorbents from different manufacturers. These studies highlight the need to evaluate critically the performance characteristics of solid-phase cartridges when the manufacturer or batch lot is changed.

Posttranscriptional regulation of mRNA levels in rat liver associated with deoxycholic acid feeding

We investigated the effects of bile acid feeding on the mRNA levels and transcriptional activity of genes involved in various facets of hepatic cell function. Rats were maintained for 10 days on standard diet supplemented with combinations of 1 and 0.4% deoxycholic acid and ursodeoxycholic acid. Significant reductions in mRNA levels for liver fatty acid binding protein, albumin, the asialoglycoprotein receptor, connexins 32 and 26, and cytochromes P-450IIB1 and P-450IIE1 were associated with 1% deoxycholic acid feeding. Conversely, the 1% deoxycholic acid-fed animals exhibited increased mRNA levels for cholesterol 7 alpha-hydroxylase, 3-hydroxy-3-methylglutaryl-CoA reductase, multidrug resistance, procollagens, extracellular matrix, protooncogenes, tumor suppressors, and cyclins. The 0.4% deoxycholic acid-fed animals exhibited increased mRNA levels for c-jun, H-ras, p53, cyclins D1 and D3, fibronectin, and procollagens alpha 1(I) and alpha 1(III). Transcriptional rate changes could not account for the observed changes in steady-state mRNA levels. Ursodeoxycholic acid feeding had no significant effect on gene expression and almost completely inhibited the changes associated with 1% deoxycholic acid when coadministered. The results indicate that dietary ingestion of deoxycholic acid profoundly affects hepatic gene expression in the rat, and regulation occurs primarily at the posttranscriptional level.

The site-specific delivery of ursodeoxycholic acid to the rat colon by sulfate conjugation

BACKGROUND & AIMS

Because ursodeoxycholate has been shown to act as a tumor-suppressive agent in the colon, the absorption and metabolism of its sulfate conjugates were examined in rats to show that sulfation would facilitate the site-specific delivery of ursodeoxycholate to the colon.

METHODS

Bile acids were measured in intestinal contents, feces, urine, plasma, and liver tissue after oral administration of ursodeoxycholate and its C-3, C-7, and C-3,7 sulfate derivatives.

RESULTS

Ursodeoxycholate was found in the jejunum after administration of all bile acids, but the mass was greatest for ursodeoxycholic acid administration. In the colon, lithocholic acid, normally found in negligible amounts, became the major bile acid after ursodeoxycholate administration. In contrast, reductions in mass and proportions of lithocholate and deoxycholate occurred after administering the C-7 sulfates. The fecal lithocholate/deoxycholate ratio, a risk marker for colon cancer, increased markedly after administration of ursodeoxycholate and its C-3 sulfate, but did not change after administering the C-7 sulfates. Unlike ursodeoxycholate or its C-3 sulfate, which increased liver concentrations of lithocholate and ursodeoxycholate, the C-7 sulfates had the opposite effect, which was consistent with poor absorption.

CONCLUSIONS

Sulfation of ursodeoxycholate, specifically at the C-7 position, protects the molecule from bacterial degradation and inhibits its intestinal absorption, thereby facilitating delivery to the colon.

Tauroursodeoxycholate increases rat liver ursodeoxycholate levels and limits lithocholate formation better than ursodeoxycholate

BACKGROUND & AIMS

To explain the greater hepatoprotective effect of tauroursodeoxycholic acid vs. ursodeoxycholic acid, the absorption, hepatic enrichment, and biotransformation of these bile acids (250 mg/day) were compared in rats.

METHODS

Bile acids were determined in intestinal contents, feces, urine, plasma, and liver by gas chromatography-mass spectrometry.

RESULTS

The concentration of ursodeoxycholate in the liver of animals administered tauroursodeoxycholic acid (175 +/- 29 nmol/g) was greater (P < 0.05) than in animals administered ursodeoxycholic acid (79 +/- 19 nmol/g). Hepatic lithocholate was substantially higher after ursodeoxycholic acid administration (21 +/- 10 nmol/g) than after tauroursodeoxycholic acid administration (12 +/- 1 nmol/g). A concomitant reduction in the proportion of hydrophobic bile acids occurred that was greatest during tauroursodeoxycholic acid administration. In the intestinal tract, the mass of ursodeoxycholate and its specific metabolites was greater in rats administered tauroursodeoxycholic acid (27.2 mg) than those administered ursodeoxycholic acid (13.2 mg). In feces, the proportion of lithocholate was 21.9% +/- 4.9% and 5.4% +/- 4.0% after ursodeoxycholic acid and tauroursodeoxycholic acid administration, respectively.

CONCLUSIONS

Compared with ursodeoxycholic acid, tauroursodeoxycholic acid induces a greater decrease in the percent composition of more hydrophobic bile acids within the pool, limits lithocholate formation, and increases hepatic ursodeoxycholate concentration. These differences are explained by increased hepatic extraction and reduced intestinal biotransformation and not by enhanced absorption of the amidated species.

delta 22-Ursodeoxycholic acid, a unique metabolite of administered ursodeoxycholic acid in rats, indicating partial beta-oxidation as a major pathway for bile acid metabolism

We describe for the first time the identification of 3 alpha, 7 beta-dihydroxy-5 beta-chol-22-en-24-oic acid (delta 22-UDCA) in the plasma, bile, intestinal contents, and liver tissue of Sprague-Dawley rats after intravenous and oral administration of ursodeoxycholic acid (UDCA). Infusion of [2,2,4,4-2H4]UDCA confirmed delta 22-UDCA to be a specific metabolite of UDCA. Definitive confirmation of this unique and major metabolite was established by liquid secondary ionization mass spectrometry and gas chromatography-mass spectrometry by comparison of the retention index and mass spectrum with an authentic standard of delta 22-UDCA. When rats were fed a diet containing 1.0% UDCA, high concentrations of delta 22-UDCA were found in the plasma (40.3 +/- 11.8 mumol/L) and liver tissue (300.9 +/- 64.2 nmol/g of tissue), and these represented 36% and 57%, respectively, of the UDCA concentration. In animals fed 0.4% and 1.0% UDCA, the mass of delta 22-UDCA in the jejunum was high (7.5 +/- 0.9 and 6.6 +/- 0.6 mg, respectively), accounting for 50-60% of the total UDCA, but diminished markedly along the intestine, accounting for < 3% of the total UDCA in the colon. Although delta 22-UDCA was not found in biological samples from control rats, delta 22-beta-muricholic and delta 22-omega-muricholic acids were normal constituents of plasma and intestinal contents and were major muricholate isomers in liver tissue and bile. Synthesis of delta 22-bile acids appears to be highly specific toward bile acids possessing a functional 7 beta-hydroxyl group. We presume that, in common with pathways for endogenous bile acid synthesis, partial side-chain oxidation of UDCA occurs in the peroxisome with formation of alpha/beta unsaturation; since UDCA has only a 5-carbon side chain, release of propionic or acetic acid is not possible, beta-oxidation proceeds no further, and delta 22-UDCA is formed. While the mechanism of formation and physiological significance of delta 22-bile acids remain to be established, our data indicate that partial beta-oxidation is a quantitatively important pathway for endogenous bile acid synthesis and for UDCA metabolism in this species.

Sterilization approval and follow-through in Brazil

The purpose of this study was to examine the factors that affect approval for and completion of sterilization in Rio de Janeiro. Of 2,186 new female family planning clients, 1,256 requested sterilization and 925 were approved for surgery. Among the approved women, 639 scheduled surgery and, of these, 595 were sterilized within three months of approval. While approval is dependent mainly on demographic variables, especially age and parity, follow-through by a woman is related to her education and income. The steps that a woman must complete to obtain a sterilization also affect whether she ultimately undergoes surgery. Almost no women were scheduled for sterilization during their initial clinic visit. Women who were not scheduled because they lacked certain documentation were more likely to follow through than women who, in addition to lacking documentation, were asked to switch from an inefficient contraceptive method (or no method) to a more modern one. The lessons to be learned from this study provide useful information to programs in other countries that are concerned about maintaining high standards but do not want to discourage women in their efforts to be sterilized.